Systems and methods for enhancing optical information

DOEpatents

DeVore, Peter Thomas Setsuda; Chou, Jason T.

2018-01-02

An Optical Information Transfer Enhancer System includes a first system for producing an information bearing first optical wave that is impressed with a first information having a first information strength wherein the first optical wave has a first shape. A second system produces a second optical wave. An information strength enhancer module receives the first and said second optical waves and impresses the first optical wave upon the second optical wave via cross-phase modulation (XPM) to produce an information-strength-enhanced second optical wave having a second information strength that is greater than the first information strength of the first optical wave. Following a center-wavelength changer by an Optical Information Transfer Enhancer System improves its performance.

Advanced optical fiber communication systems

NASA Astrophysics Data System (ADS)

Kazovsky, Leonid G.

1994-03-01

Our research is focused on three major aspects of advanced optical fiber communication systems: dynamic wavelength division multiplexing (WDM) networks, fiber nonlinearities, and high dynamic range coherent analog optical links. In the area of WDM networks, we have designed and implemented two high-speed interface boards and measured their throughput and latency. Furthermore, we designed and constructed an experimental PSK/ASK transceiver that simultaneously transmits packet-switched ASK data and circuit-switched PSK data on the same optical carrier. In the area of fiber nonlinearities, we investigated the theoretical impact of modulation frequency on cross-phase modulation (XPM) in dispersive fibers. In the area of high dynamic range coherent analog optical links, we developed theoretical expressions for the RF power transfer ratio (or RF power gain) and the noise figure (NF) of angle-modulated links. We then compared the RF power gains and noise figures of these links to that of an intensity modulated direct detection (DD) link.

Effect of control-beam polarization and power on optical time-domain demultiplexing in a new nonlinear optical loop mirror design

NASA Astrophysics Data System (ADS)

Grendár, Drahomír; Pottiez, Olivier; Dado, Milan; Müllerová, Jarmila; Dubovan, Jozef

2009-05-01

A new scheme of a control-beam-driven nonlinear optical loop mirror (NOLM) with a birefringent twisted fiber and a symmetrical coupler designed for optical time division demultiplexing (OTDM) is analyzed. The theoretical model of the proposed NOLM scheme considers the evolution of polarization states of data and control beams and the mutual interactions of the data and control beams due to the cross-phase modulation (XPM). Attention is given to the optical switching commanded by the control-beam power and by the manipulation of nonlinear polarization rotation of the data and control beam. The simulations of NOLM transmissions demonstrate that the cross talk between demultiplexed and nondemultiplexed beams as an important parameter for optical switching by the presented NOLM can be significantly reduced. The results show that the device can be of interest for all-optical signal manipulations in optical communication networks.

Five-order SRSs and supercontinuum generation from a tapered tellurite microstructured fiber with longitudinally varying dispersion.

PubMed

Liao, Meisong; Yan, Xin; Gao, Weiqing; Duan, Zhongchao; Qin, Guanshi; Suzuki, Takenobu; Ohishi, Yasutake

2011-08-01

We try to obtain stable supercontinuum (SC) generation with broad bandwidth under relative simple pump conditions. We use a 1.3-m-long highly nonlinear tellurite microstructured fiber and pump it by a 15 ps 1064 nm fiber laser. One segment of the fiber is tapered from a core diameter of 3.4 μm to 1.3 μm. For the first time five-order stimulated Raman scatterings (SRSs) are observed for soft glass fibers. SC covering 730-1700 nm is demonstrated with the pump-pulse-energy of several nJ. The mechanisms of SC broadening are mainly SRS, self-phase modulation (SPM) and cross phase modulation (XPM). The tapered segment has two advantages. Firstly it increases the nonlinearity of fiber by several times. Secondly, it acts as a compensation for the dispersion of the untapered segment, and mitigates the walk-off between pump pulse and SRS peaks.

A Novel Dynamic Physical Layer Impairment-Aware Routing and Wavelength Assignment (PLI-RWA) Algorithm for Mixed Line Rate (MLR) Wavelength Division Multiplexed (WDM) Optical Networks

NASA Astrophysics Data System (ADS)

Iyer, Sridhar

2016-12-01

The ever-increasing global Internet traffic will inevitably lead to a serious upgrade of the current optical networks' capacity. The legacy infrastructure can be enhanced not only by increasing the capacity but also by adopting advance modulation formats, having increased spectral efficiency at higher data rate. In a transparent mixed-line-rate (MLR) optical network, different line rates, on different wavelengths, can coexist on the same fiber. Migration to data rates higher than 10 Gbps requires the implementation of phase modulation schemes. However, the co-existing on-off keying (OOK) channels cause critical physical layer impairments (PLIs) to the phase modulated channels, mainly due to cross-phase modulation (XPM), which in turn limits the network's performance. In order to mitigate this effect, a more sophisticated PLI-Routing and Wavelength Assignment (PLI-RWA) scheme needs to be adopted. In this paper, we investigate the critical impairment for each data rate and the way it affects the quality of transmission (QoT). In view of the aforementioned, we present a novel dynamic PLI-RWA algorithm for MLR optical networks. The proposed algorithm is compared through simulations with the shortest path and minimum hop routing schemes. The simulation results show that performance of the proposed algorithm is better than the existing schemes.

Optical analog-to-digital converter

DOEpatents

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

2009-07-21

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

Pump RIN-induced impairments in unrepeatered transmission systems using distributed Raman amplifier.

PubMed

Cheng, Jingchi; Tang, Ming; Lau, Alan Pak Tao; Lu, Chao; Wang, Liang; Dong, Zhenhua; Bilal, Syed Muhammad; Fu, Songnian; Shum, Perry Ping; Liu, Deming

2015-05-04

High spectral efficiency modulation format based unrepeatered transmission systems using distributed Raman amplifier (DRA) have attracted much attention recently. To enhance the reach and optimize system performance, careful design of DRA is required based on the analysis of various types of impairments and their balance. In this paper, we study various pump RIN induced distortions on high spectral efficiency modulation formats. The vector theory of both 1st and higher-order stimulated Raman scattering (SRS) effect using Jones-matrix formalism is presented. The pump RIN will induce three types of distortion on high spectral efficiency signals: intensity noise stemming from SRS, phase noise stemming from cross phase modulation (XPM), and polarization crosstalk stemming from cross polarization modulation (XPolM). An analytical model for the statistical property of relative phase noise (RPN) in higher order DRA without dealing with complex vector theory is derived. The impact of pump RIN induced impairments are analyzed in polarization-multiplexed (PM)-QPSK and PM-16QAM-based unrepeatered systems simulations using 1st, 2nd and 3rd-order forward pumped Raman amplifier. It is shown that at realistic RIN levels, negligible impairments will be induced to PM-QPSK signals in 1st and 2nd order DRA, while non-negligible impairments will occur in 3rd order case. PM-16QAM signals suffer more penalties compared to PM-QPSK with the same on-off gain where both 2nd and 3rd order DRA will cause non-negligible performance degradations. We also investigate the performance of digital signal processing (DSP) algorithms to mitigate such impairments.

Determination of spectral limits imposed by four-wave mixing and amplified spontaneous emission in the 1550 nm region

NASA Astrophysics Data System (ADS)

Alvarez-Chavez, J. A.; Sanchez-Lara, R.; Martinez-Piñon, F.; Mendez-Martinez, F.; de la Cruz-May, L.; Perez-Sanchez, G. G.

2015-04-01

Dense wavelength division multiplexing (DWDM) systems are normally limited by stimulated Brillouin scattering (SBS), stimulated Raman scattering (SRS), self-phase modulation (SPM), cross-phase modulation (XPM) and four-wave mixing (FWM) besides amplified spontaneous emission (ASE) noise from erbium-doped fiber amplifiers (EDFAs). In this paper, theoretical calculation of FWM-based limits and noise from EDFAs in the 1535-1565 nm region, are reported. Results show that FWM power per channel extended from -55 to -20 dBm for dispersion values of 0.0, 0.5, 1.0 and 1.5 ps (nmṡkm)-1. In a similar manner, for negative dispersion coefficient (D) values ranging from 0.0 to -1.5 ps (nmṡkm)-1, the FWM power per channel extended from -60 to -30 dBm. As for the maximum span length, the calculations demonstrated a rigorous limitation due to noise, suggesting error compensation techniques. A full set of results for the design of multi-span links is included.

Exact modelling of the optical bistability in ferroelectics via two-wave mixing: A system with full nonlinearity

NASA Astrophysics Data System (ADS)

Khushaini, Muhammad Asif A.; Ibrahim, Abdel-Baset M. A.; Choudhury, P. K.

2018-05-01

In this paper, we provide a complete mathematical model of the phenomenon of optical bistability (OB) resulting from the degenerate two-wave mixing (TWM) process of laser beams interacting with a single nonlinear layer of ferroelectric material. Starting with the electromagnetic wave equation for optical wave propagating in nonlinear media, a nonlinear coupled wave (CW) system with both self-phase modulation (SPM) and cross-phase modulation (XPM) sources of nonlinearity are derived. The complete CW system with full nonlinearity is solved numerically and a comparison between both the cases of with and without SPM at various combinations of design parameters is given. Furthermore, to provide a reliable theoretical model for the OB via TWM process, the results obtained theoretically are compared with the available experimental data. We found that the nonlinear system without SPM fails to predict the bistable response at lower combinations of the input parameters. However, at relatively higher values, the solution without SPM shows a reduction in the switching contrast and period in the OB response. A comparison with the experimental results shows better agreement with the system with full nonlinearity.

Light curing through glass ceramics with a second- and a third-generation LED curing unit: effect of curing mode on the degree of conversion of dual-curing resin cements.

PubMed

Flury, Simon; Lussi, Adrian; Hickel, Reinhard; Ilie, Nicoleta

2013-12-01

The aim of this study was to measure the degree of conversion (DC) of five dual-curing resin cements after different curing modes with a second- and a third-generation light-emitting diode (LED) curing unit. Additionally, irradiance of both light curing units was measured at increasing distances and through discs of two glass ceramics for computer-aided design/manufacturing (CAD/CAM). Irradiance and spectra of the Elipar FreeLight 2 (Standard Mode (SM)) and of the VALO light curing unit (High Power Mode (HPM) and Xtra Power Mode (XPM)) were measured with a MARC radiometer. Irradiance was measured at increasing distances (control) and through discs (1.5 to 6 mm thickness) of IPS Empress CAD and IPS e.max CAD. DC of Panavia F2.0, RelyX Unicem 2 Automix, SpeedCEM, BisCem, and BeautiCem SA was measured with an attenuated total reflectance-Fourier transform infrared spectrometer when self-cured (negative control) or light cured in SM for 40 s, HPM for 32 s, or XPM for 18 s. Light curing was performed directly (positive control) or through discs of either 1.5- or 3-mm thickness of IPS Empress CAD or IPS e.max CAD. DC was analysed with Kruskal-Wallis tests followed by pairwise Wilcoxon rank sum tests (α = 0.05). Maximum irradiances were 1,545 mW/cm(2) (SM), 2,179 mW/cm(2) (HPM), and 4,156 mW/cm(2) (XPM), and all irradiances decreased by >80 % through discs of 1.5 mm, ≥95 % through 3 mm, and up to >99 % through 6 mm. Generally, self-curing resulted in the lowest DC. For some cements, direct light curing did not result in higher DC compared to when light cured through ceramic discs. For other cements, light curing through ceramic discs of 3 mm generally reduced DC. Light curing was favourable for dual-curing cements. Some cements were more susceptible to variations in curing mode than others. When light curing a given cement, the higher irradiances of the third-generation LED curing unit resulted in similar DC compared to the second-generation one, though at shorter light curing times.

Silicon Photonics: All-Optical Devices for Linear and Nonlinear Applications

NASA Astrophysics Data System (ADS)

Driscoll, Jeffrey B.

Silicon photonics has grown rapidly since the first Si electro-optic switch was demonstrated in 1987, and the field has never grown more quickly than it has over the past decade, fueled by milestone achievements in semiconductor processing technologies for low loss waveguides, high-speed Si modulators, Si lasers, Si detectors, and an enormous toolbox of passive and active integrated devices. Silicon photonics is now on the verge of major commercialization breakthroughs, and optical communication links remain the force driving integrated and Si photonics towards the first commercial telecom and datacom transceivers; however other potential and future applications are becoming uncovered and refined as researchers reveal the benefits of manipulating photons on the nanoscale. This thesis documents an exploration into the unique guided-wave and nonlinear properties of deeply-scaled high-index-contrast sub-wavelength Si waveguides. It is found that the tight confinement inherent to single-mode channel waveguides on the silicon-on-insulator platform lead to a rich physics, which can be leveraged for new devices extending well beyond simple passive interconnects and electro-optic devices. The following chapters will concentrate, in detail, on a number of unique physical features of Si waveguides and extend these attributes towards new and interesting devices. Linear optical properties and nonlinear optical properties are investigated, both of which are strongly affected by tight optical confinement of the guided waveguide modes. As will be shown, tight optical confinement directly results in strongly vectoral modal components, where the electric and magnetic fields of the guided modes extend into all spatial dimensions, even along the axis of propagation. In fact, the longitudinal electric and magnetic field components can be just as strong as the transverse fields, directly affecting the modal group velocity and energy transport properties since the longitudinal fields are shown to contribute no time-averaged momentum. Furthermore, the vectoral modal components, in conjunction with the tensoral nature of the third-order susceptibility of Si, lead to nonlinear properties which are dependent on waveguide orientation with respect to the Si parent crystal and the construction of the modal electric field components. This consideration is used to maximize effective nonlinearity and realize nonlinear Kerr gratings along specific waveguide trajectories. Tight optical confinement leads to a natural enhancement of the intrinsically large effective nonlinearty of Si waveguides, and in fact, the effective nonlinearty can be made to be almost 106 times greater in Si waveguides than that of standard single-mode fiber. Such a large nonlinearity motivates chip-scale all-optical signal processing techniques. Wavelength conversion by both four-wave-mixing (FWM) and cross-phase-modulation (XPM) will be discussed, including a technique that allows for enhanced broadband discrete FWM over arbitrary spectral spans by modulating both the linear and nonlinear waveguide properties through periodic changes in waveguide geometry. This quasi-phase-matching approach has very real applications towards connecting mature telecom sources detectors and components to other spectral regimes, including the mid-IR. Other signal processing techniques such as all-optical modulation format conversion via XPM will also be discussed. This thesis will conclude by looking at ways to extend the bandwidth capacity of Si waveguide interconnects on chip. As the number of processing cores continues to scale as a means for computational performance gains, on-chip link capacity will become an increasingly important issue. Metallic traces have severe limitations and are envisioned to eventually bow to integrated photonic links. The aggregate bandwidth supported by a single waveguide link will therefore become a crucial consideration as integrated photonics approaches the CPU. One way to increase aggregate bandwidth is to utilize different eigen-modes of a multimode waveguide, and integrated waveguide mode-muxes and demuxes for achieving simultaneous mode-division-multiplexing and wavelength-division-multiplexing will be demonstrated.

The Kinematics Parameters of the Galaxy Using Data of Modern Astrometric Catalogues

NASA Astrophysics Data System (ADS)

Akhmetov, V. S.; Fedorov, P. N.; Velichko, A. B.; Shulga, V. M.

Based on the Ogorodnikov-Milne model, we analyze the proper motions of XPM2, UCAC4 and PPMXL stars. To estimate distances to the stars we used the method of statistical parallaxes herewith the random errors of the distance estimations do not exceed 10%. The method of statistical parallaxes was used to estimate the distances to stars with random errors no larger than 14%. The linear solar velocity relative to the local standard of rest, which is well determined for the local entroid (d 150 p), was used as a reference. We have established that the model component that describes the rotation of all stars under consideration about the Galactic Y axis differs from zero. For the distant (d < 1000 pc) PPMXL and UCAC4 stars, the mean rotation about the Galactic Y axis has been found to be M-13 = -0.75± 0.04 mas yr-1. As for distances greater than 1 kpc M-13>derived from the data of only XPM2 catalogue becomes positive and exceeds 0.5 mas yr-1. We interpret this rotation found using the distant stars as a residual rotation of the ICRS/Tycho-2 system relative to the inertial reference frame.

Future optical communication networks beyond 160 Gbit/s based on OTDM

NASA Astrophysics Data System (ADS)

Prati, Giancarlo; Bogoni, Antonella; Poti, Luca

2005-01-01

The virtually unlimited bandwidth of optical fibers has caused a great increase in data transmission speed over the past decade and, hence, stimulated high-demand multimedia services such as distance learning, video-conferencing and peer to peer applications. For this reason data traffic is exceeding telephony traffic, and this trend is driving the convergence of telecommunications and computer communications. In this scenario Internet Protocol (IP) is becoming the dominant protocol for any traffic, shifting the attention of the network designers from a circuit switching approach to a packet switching approach. A role of paramount importance in packet switching networks is played by the router that must implement the functionalities to set up and maintain the inter-nodal communications. The main functionalities a router must implement are routing, forwarding, switching, synchronization, contention resolution, and buffering. Nowadays, opto-electronic conversion is still required at each network node to process the incoming signal before routing that to the right output port. However, when the single channel bit rate increases beyond electronic speed limit, Optical Time Division Multiplexing (OTDM) becomes a forced choice, and all-optical processing must be performed to extract the information from the incoming packet. In this paper enabling techniques for ultra-fast all-optical network will be addressed. First a 160 Gbit/s complete transmission system will be considered. As enabling technique, an overview for all-optical logics will be discussed and experimental results will be presented using a particular reconfigurable NOLM based on Self-Phase-Modulation (SPM) or Cross-Phase-Modulation (XPM). Finally, a rough experiment on label extraction, all-optical switching and packet forwarding is shown.

Handbook for Strategic Air Command (SAC) Management Engineering Officers (MEOs)

DTIC Science & Technology

1985-04-01

JACK D. MARTIN, USAF FACULTY ADVISOR« MAJOR ROBERT M. WEIS, ACSC/ EDX SPONSOR« COLONEL DENNIS D. GRAVES, HQ SAC/XPM Submitted to the...8217^^^!^^^’T^^T^^TTT^"?,^w, Fr ’,^’TTrT^TTrTT,Tr,T^’ in AFR 25-5, then close the book and perform the task satisfac- tcsrily? The key to...Command and Staff College, Air University (ATC), Maxwell AFB, Alabama, 1981. 130 o.V ^^^^^^ WWW ^^^^T^^^^^^^I^^^^^^^^^^^^^W»^»>T»>il)’»M’j MJM ■iii.ii

Single pulse two-photon fluorescence lifetime imaging (SP-FLIM) with MHz pixel rate and an all fiber based setup

NASA Astrophysics Data System (ADS)

Eibl, Matthias; Karpf, Sebastian; Hakert, Hubertus; Weng, Daniel; Pfeiffer, Tom; Kolb, Jan Philip; Huber, Robert

2017-07-01

Newly developed microscopy methods have the goal to give researches in bio-molecular science a better understanding of processes ongoing on a cellular level. Especially two-photon excited fluorescence (TPEF) microscopy is a readily applied and widespread modality. Compared to one photon fluorescence imaging, it is possible to image not only the surface but also deeper lying structures. Together with fluorescence lifetime imaging (FLIM), which provides information on the chemical composition of a specimen, deeper insights on a molecular level can be gained. However, the need for elaborate light sources for TPEF and speed limitations for FLIM hinder an even wider application. In this contribution, we present a way to overcome this limitations by combining a robust and inexpensive fiber laser for nonlinear excitation with a fast analog digitization method for rapid FLIM imaging. The applied sub nanosecond pulsed laser source is perfectly suited for fiber delivery as typically limiting non-linear effects like self-phase or cross-phase modulation (SPM, XPM) are negligible. Furthermore, compared to the typically applied femtosecond pulses, our longer pulses produce much more fluorescence photons per single shot. In this paper, we show that this higher number of fluorescence photons per pulse combined with a high analog bandwidth detection makes it possible to not only use a single pulse per pixel for TPEF imaging but also to resolve the exponential time decay for FLIM. To evaluate our system, we acquired FLIM images of a dye solution with single exponential behavior to assess the accuracy of our lifetime determination and also FLIM images of a plant stem at a pixel rate of 1 MHz to show the speed performance of our single pulse two-photon FLIM (SP-FLIM) system.

Polarization-insensitive all-optical dual pump-phase transmultiplexing from 2 x 10-GBd OOKs to 10-GBd RZ-QPSK using cross-phase modulation in a passive nonlinear birefringent photonic crystal fiber

NASA Astrophysics Data System (ADS)

Mahmood, Tanvir

Considering the network size, bit rate, spectral and channel capacity limitations, different modulation formats may be selectively used in future optical networks. Although the traditional metropolitan area networks (MANs) still uses the non-return-to-zero on-off keying (NRZ-OOK) modulation format due to its technical simplicity and therefore low cost, QPSK format is more advantageous in spectrally efficient long-haul fiber optic transmission systems because of its constant power envelope, and robustness to various transmission impairments. Consequently, an important problem may arise, in particular how to route the OOK-data streams from MANs to long-haul backbone networks when the state of polarization (SOP) of the remotely generated OOK is unpredictable. Hence, the focus of this dissertation was to investigate a polarization insensitive (PI) all-optical nonlinear optical signal processing (NOSP) method that can be implemented at the network cross-connect (X-connect) to transfer data from a remotely and a locally generated OOK data simultaneously to more effectual QPSK format for long-haul transmission. By utilizing cross-phase modulation (XPM) and inherent birefringence of the device, the work demonstrated, for the first time, PI all-optical data transfer utilizing dual pump-phase transmultiplexing (DPTM) from 2 x 10-GBd OOKs to 10-GBd RZ-QPSK in a passive nonlinear birefringent photonic crystal fiber (PCF). Polarization insensitivity was achieved by scrambling the SOP of the remotely generated OOK pump and launching the locally generated OOK pump and the probe off-axis. To mitigate polarization induced power fluctuations and detrimental effects due to nearby partially degenerate and non-degenerate four wave mixings, an optimum pump-probe detuning was also utilized. The PI DPTM RZ-QPSK demonstrated a pre-amplified receiver sensitivity penalty < 5.5 dB at 10--9 bit-error-rate (BER), relative to relative to the FPGA-precoded RZ-DQPSK baseline in ASE-limited transmission system. The effect of the remotely generated OOK pump OSNR degradation on PI DPTM RZ-QPSK was also investigated and it was established that 10 -9 BER metric was attainable till the remotely generated OOK pump reached the threshold OSNR limit of 34 dB/0.1nm. Finally, DWDM transmission performance of the PI DPTM RZ-QPSK signal was evaluated using 138-km long recirculating loop and it was demonstrated that the PI DPTM RZ-QPSK can be transmitted over 1,500 km before it reached ITU-T G.709 7% HD-FEC overhead limit. This propagation distance was well beyond the transmission requisites of any typical metro network (≈ 600 km). Furthermore, it was demonstrated that, within the threshold limit, OSNR degradation of the remotely generated OOK pump had minimal impact on the transmission distance of the PI DPTM RZ-QPSK before it reached 7% HD-FEC overhead limit.

Generation and Amplification of Tunable Multicolored Femtosecond Laser Pulses by Using Cascaded Four-Wave Mixing in Transparent Bulk Media

PubMed Central

Liu, Jun; Kobayashi, Takayoshi

2010-01-01

We have reviewed the generation and amplification of wavelength-tunable multicolored femtosecond laser pulses using cascaded four-wave mixing (CFWM) in transparent bulk media, mainly concentrating on our recent work. Theoretical analysis and calculations based on the phase-matching condition could explain well the process semi-quantitatively. The experimental studies showed: (1) as many as fifteen spectral up-shifted and two spectral down-shifted sidebands were obtained simultaneously with spectral bandwidth broader than 1.8 octaves from near ultraviolet (360 nm) to near infrared (1.2 μm); (2) the obtained sidebands were spatially separated well and had extremely high beam quality with M2 factor better than 1.1; (3) the wavelengths of the generated multicolor sidebands could be conveniently tuned by changing the crossing angle or simply replacing with different media; (4) as short as 15-fs negatively chirped or nearly transform limited 20-fs multicolored femtosecond pulses were obtained when one of the two input beams was negatively chirped and the other was positively chirped; (5) the pulse energy of the sideband can reach a μJ level with power stability better than 1% RMS; (6) broadband two-dimensional (2-D) multicolored arrays with more than ten periodic columns and more than ten rows were generated in a sapphire plate; (7) the obtained sidebands could be simultaneously spectra broadened and power amplified in another bulk medium by using cross-phase modulation (XPM) in conjunction with four-wave optical parametric amplification (FOPA). The characterization showed that this is interesting and the CFWM sidebands generated by this novel method have good enough qualities in terms of power stability, beam quality, and temporal features suited to various experiments such as ultrafast multicolor time-resolved spectroscopy and multicolor-excitation nonlinear microscopy. PMID:22399882

Commission 8: Astrometry

NASA Astrophysics Data System (ADS)

Evans, Dafydd Wyn; Zacharias, Norbert; Kumkova, Irina; Andrei, Alexandre; Brown, Anthony; Gouda, Naoteru; Popescu, Petre; Souchay, Jean; Unwin, Stephen; Zhu, Zi

2012-04-01

Gaia is continuing well with its development and construction and is expected to achieve parallax accuracies of about 10 to 300 μas for 6 to 20 mag. It is scheduled to launch in 2013. The ICRF2 was adopted by the IAU in 2009 as the new fundamental celestial reference frame. The UCAC project concluded with the publication of its 4th data release (all-sky, over 100 million stars). The JASMINE project will launch the Nano-JASMINE satellite in 2012 and continues with the development of its other satellites which will complement the Gaia project. The PPMXL (Heidelberg) and XPM (Ukraine) catalogues provide improved astrometric accuracies from new reductions of USNO-B (USNO-A) and 2MASS data. It is disappointing that the SIM project was cancelled during this triennium. It would have further complemented the above two satellite projects and would have gone even beyond Gaia in astrometric accuracy.

Optimization of TiO2/Cu/TiO2 multilayers as a transparent composite electrode deposited by electron-beam evaporation at room temperature

NASA Astrophysics Data System (ADS)

Sun, Hong-Tao; Wang, Xiao-Ping; Kou, Zhi-Qi; Wang, Li-Jun; Wang, Jin-Ye; Sun, Yi-Qing

2015-04-01

Highly transparent indium-free composite electrodes of TiO2/Cu/TiO2 are deposited by electron-beam evaporation at room temperature. The effects of Cu thickness and annealing temperature on the electrical and optical properties of the multilayer film are investigated. The critical thickness of Cu mid-layer to form a continuous conducting layer is found to be 11 nm. The multilayer with a mid-Cu thickness of 11 nm is optimized to obtain a resistivity of 7.4×10-5 Ω·cm and an average optical transmittance of 86% in the visible spectral range. The figure of merit of the TiO2/Cu(11 nm)/TiO2 multilayer annealed at 150 °C reaches a minimum resistivity of 5.9×10-5 Ω·cm and an average optical transmittance of 88% in the visible spectral range. The experimental results indicate that TiO2/Cu/TiO2 multilayers can be used as a transparent electrode for solar cell and other display applications. Project supported by the Research Innovation Key Project of Education Committee of Shanghai, China (Grant No. 14ZZ137) and the National Cultivation Fund from University of Shanghai for Science and Technology (Grant No. 14XPM04).

[Quality control of laser imagers].

PubMed

Winkelbauer, F; Ammann, M; Gerstner, N; Imhof, H

1992-11-01

Multiformat imagers based on laser systems are used for documentation in an increasing number of investigations. The specific problems of quality control are explained and the persistence of film processing in these imager systems of different configuration with (Machine 1: 3M-Laser-Imager-Plus M952 with connected 3M Film-Processor, 3M-Film IRB, X-Rax Chemical Mixer 3M-XPM, 3M-Developer and Fixer) or without (Machine 2: 3M-Laser-Imager-Plus M952 with separate DuPont-Cronex Film-processor, Kodak IR-Film, Kodak Automixer, Kodak-Developer and Fixer) connected film processing unit are investigated. In our checking based on DIN 6868 and ONORM S 5240 we found persistence of film processing in the equipment with directly adapted film processing unit according to DIN and ONORM. The checking of film persistence as demanded by DIN 6868 in these equipment could therefore be performed in longer periods. Systems with conventional darkroom processing comparatively show plain increased fluctuation, and hence the demanded daily control is essential to guarantee appropriate reaction and constant quality of documentation.

Study of the $${X^\\pm(5568)}$$ state with semileptonic decays of the $${B_s^0}$$ meson

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abazov, Victor Mukhamedovich; et al.

2018-05-19

We present a study of the X±(5568) using semileptonic decays of the Bs0 meson using the full run II integrated luminosity of 10.4  fb-1 in proton-antiproton collisions at a center of mass energy of 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. We report evidence for a narrow structure, X±(5568), in the decay sequence X±(5568)→Bs0π± where Bs0→μ∓Ds±X, Ds±→ϕπ± which is consistent with the previous measurement by the D0 Collaboration in the hadronic decay mode, X±(5568)→Bs0π± where Bs0→J/ψϕ. The mass and width of this state are measured using a combined fit of the hadronic and semileptonic data, yielding m=5566.9-3.1+3.2(stat)-1.2+0.6(syst)  MeV/c2,more » Γ=18.6-6.1+7.9(stat)-3.8+3.5(syst)  MeV/c2 with a significance of 6.7σ.« less

An isotopic approach to measuring nitrogen balance in caribou

USGS Publications Warehouse

Gustine, David D.; Barboza, Perry S.; Adams, Layne G.; Farnell, Richard G.; Parker, Katherine L.

2011-01-01

Nutritional restrictions in winter may reduce the availability of protein for reproduction and survival in northern ungulates. We refined a technique that uses recently voided excreta on snow to assess protein status in wild caribou (Rangifer tarandus) in late winter. Our study was the first application of this non‐invasive, isotopic approach to assess protein status of wild caribou by determining dietary and endogenous contributions of nitrogen (N) to urinary urea. We used isotopic ratios of N (δ15N) in urine and fecal samples to estimate the proportion of urea N derived from body N (p‐UN) in pregnant, adult females of the Chisana Herd, a small population that ranged across the Alaska‐Yukon border. We took advantage of a predator‐exclosure project to examine N status of penned caribou in April 2006. Lichens were the primary forage (>40%) consumed by caribou in the pen and δ15N of fiber tracked the major forages in their diets. The δ15N of urinary urea for females in the pen was depleted relative (−1.3 ± 1.0 parts per thousand [‰], ${\\bar {x}}\\pm {\\rm SD}$) to the δ15N of body N (2.7 ± 0.7‰). A similar proportion of animals in the exclosure lost core body mass (excluding estimates of fetal and uterine tissues; 55%) and body protein (estimated by isotope ratios; 54%). This non‐invasive technique could be applied at various spatial and temporal scales to assess trends in protein status of free‐ranging populations of northern ungulates. Intra‐ and inter‐annual estimates of protein status could help managers monitor effects of foraging conditions on nutritional constraints in ungulates, increase the efficiency and efficacy of management actions, and help prepare stakeholders for potential changes in population trends.

Novel fusion for hybrid optical/microcomputed tomography imaging based on natural light surface reconstruction and iterated closest point

NASA Astrophysics Data System (ADS)

Ning, Nannan; Tian, Jie; Liu, Xia; Deng, Kexin; Wu, Ping; Wang, Bo; Wang, Kun; Ma, Xibo

2014-02-01

In mathematics, optical molecular imaging including bioluminescence tomography (BLT), fluorescence tomography (FMT) and Cerenkov luminescence tomography (CLT) are concerned with a similar inverse source problem. They all involve the reconstruction of the 3D location of a single/multiple internal luminescent/fluorescent sources based on 3D surface flux distribution. To achieve that, an accurate fusion between 2D luminescent/fluorescent images and 3D structural images that may be acquired form micro-CT, MRI or beam scanning is extremely critical. However, the absence of a universal method that can effectively convert 2D optical information into 3D makes the accurate fusion challengeable. In this study, to improve the fusion accuracy, a new fusion method for dual-modality tomography (luminescence/fluorescence and micro-CT) based on natural light surface reconstruction (NLSR) and iterated closest point (ICP) was presented. It consisted of Octree structure, exact visual hull from marching cubes and ICP. Different from conventional limited projection methods, it is 360° free-space registration, and utilizes more luminescence/fluorescence distribution information from unlimited multi-orientation 2D optical images. A mouse mimicking phantom (one XPM-2 Phantom Light Source, XENOGEN Corporation) and an in-vivo BALB/C mouse with implanted one luminescent light source were used to evaluate the performance of the new fusion method. Compared with conventional fusion methods, the average error of preset markers was improved by 0.3 and 0.2 pixels from the new method, respectively. After running the same 3D internal light source reconstruction algorithm of the BALB/C mouse, the distance error between the actual and reconstructed internal source was decreased by 0.19 mm.

Silicon photonics: Design, fabrication, and characterization of on-chip optical interconnects

NASA Astrophysics Data System (ADS)

Hsieh, I.-Wei

In recent years, the research field of silicon photonics has been developing rapidly from a concept to a demonstrated technology, and has gathered much attention from both academia and industry communities. Its many potential applications in long-haul telecommunication, mid-range data-communication, on-chip optical interconnection networks, and nano-scale sensing as well as its compatibility with electronic integrated circuits have driven much effort in realizing silicon photonics both as a disruptive technology for existing markets and as an enabling technology for new ones. Despite the promising future of silicon photonics, many fundamental issues still remain to be understood---both in the linear- and nonlinear-optical regimes. There are also many engineering challenges to make silicon photonics the gold standard in photonic integrated circuits. In this thesis, we focus on the design, fabrication, and characterization of active and passive silicon-on-insulator (SOI) photonic devices. The SOI material system differs from most conventional optical material platforms because of its high-refractive-index-contrast, which enables engineers to design very compact integrated photonic networks with sub-micron transverse waveguide dimensions and sharp bends. On the other hand, because most analytical formulas for designing waveguide devices are valid only in low-index-contrast cases, SOI photonic devices need to be analyzed numerically for accurate results. The second chapter of this thesis describes some common numerical methods such as Beam Propagation Method (BPM) and Finite Element Method (FEM) for waveguide-design simulations, and presents two design studies based on these methods. The compatibility of silicon photonic integrated circuits with conventional CMOS fabrication technology is another important aspect that distinguishes silicon photonics from others such as III-V materials and lithium niobate. However, the requirements for fabricating silicon photonic devices are quite different from those of electronic devices. Minimizing propagation losses by reducing sidewall roughness to nanometer scale over a device length of several millimeters or even centimeters has prompted researchers in academia and industry to refine the fabrication process. Chapter 3 of this thesis summarizes our efforts in fabricating silicon photonic devices using standard CMOS technology. Chapter 4 describes the characterization of nonlinear effects, including self-phase modulation (SPM), cross-phase modulation (XPM), and supercontinuum generation in silicon-wire waveguides. Silicon-wire waveguides are strip waveguides with submicron transverse dimensions, which allow strong light confinement inside the silicon core. This strong optical confinement, in addition to the large third-order nonlinear optical susceptibility of crystalline silicon, leads to a net nonlinearity which is several orders of magnitude higher than the nonlinearity of silica fiber. Significant nonlinear effects can be observed and characterized over a device length of only several millimeters in silicon wires with very small input power. These effects provide opportunities for engineers to design active silicon photonic devices which are compact and energy-efficient. Chapter 5 presents a realization of an integrated SOI optical isolator, which is a critical yet often overlooked component in photonic integrated circuits. This study shows the feasibility to make a hybrid garnet/SOI active device with very promising results. Finally, Chapter 6 summarizes our demonstration of transmitting terabit-scale data streams in silicon-wire waveguides, which is an important first-step towards enabling intra-chip interconnection networks with ultra-high bandwidths. Although the scope of this thesis is limited to providing only fractional views of the whole silicon photonics area, it provides enough references for interested readers to conduct further literature research in other aspects of silicon photonics. It is the author's hope that the thesis would convey to its readers the significance and potential of this exciting emerging technology.

Automated and comprehensive link engineering supporting branched, ring, and mesh network topologies

NASA Astrophysics Data System (ADS)

Farina, J.; Khomchenko, D.; Yevseyenko, D.; Meester, J.; Richter, A.

2016-02-01

Link design, while relatively easy in the past, can become quite cumbersome with complex channel plans and equipment configurations. The task of designing optical transport systems and selecting equipment is often performed by an applications or sales engineer using simple tools, such as custom Excel spreadsheets. Eventually, every individual has their own version of the spreadsheet as well as their own methodology for building the network. This approach becomes unmanageable very quickly and leads to mistakes, bending of the engineering rules and installations that do not perform as expected. We demonstrate a comprehensive planning environment, which offers an efficient approach to unify, control and expedite the design process by controlling libraries of equipment and engineering methodologies, automating the process and providing the analysis tools necessary to predict system performance throughout the system and for all channels. In addition to the placement of EDFAs and DCEs, performance analysis metrics are provided at every step of the way. Metrics that can be tracked include power, CD and OSNR, SPM, XPM, FWM and SBS. Automated routine steps assist in design aspects such as equalization, padding and gain setting for EDFAs, the placement of ROADMs and transceivers, and creating regeneration points. DWDM networks consisting of a large number of nodes and repeater huts, interconnected in linear, branched, mesh and ring network topologies, can be designed much faster when compared with conventional design methods. Using flexible templates for all major optical components, our technology-agnostic planning approach supports the constant advances in optical communications.

Model Development of Degradation of PV Modules Backsheet with Locating Place of Module

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kempe, Michael D; Wang, Yu; Fairbrother, Andrew

Performance of a photovoltaic (PV) module is related to the micro-environment around the module. The position of photovoltaic modules in an array row have a large effect on the yellowing and gloss of PV module backsheet exposed in Dfa climatic zone (Gaithersburg, MD) with a polyethylene naphthalate (PEN) outer layer. Stress/Response models of yellowing and gloss-losing as function of location parameters of module, including the shed, row, measurement position in a same module and the distance of module location to the row center, are under development. The module installation height had the greatest influence on degradation of PEN PV backsheetmore » in the Dfa climatic zone. The module backsheets at the end of an array have higher degradation rate (edge effect). The edge effect decreases with increasing of module installation heights.« less

SU-E-T-671: Range-Modulation Effects of Carbon Ion Beams in Lung Tissue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Witt, M; Weber, U; Simeonov, Y

Purpose: When particles traversing inhomogeneous materials like lung they show a characteristic range modulation which cannot be observed in homogeneous materials. It is possible to describe the range modulation by a convolution of an unperturbed Bragg-Curve and a normal distribution. The sigma of the normal distribution is a parameter for the strength of the modulation effect. A new material parameter (modulation power, P-mod) is introduced which is independent of the material thickness. It is defined as the square of sigma divided by the mean water equivalent thickness of the target (µ). Methods: The modulation power of lung tissue was determinedmore » by actual Bragg-peak measurements after traversing an ex-vivo porcine lung and by Monte-Carlo simulations with micro-CT data of human lung tissue. The determined modulation powers were used to show the effect of range modulation effects in a simplified treatment situation. A four centimeter spread-out Bragg-peak after traversing eight centimeter of lung tissue was simulated in FLUKA. The SOBP with and without consideration of range modulation effects were compared. Results: As well in the measurements as in the MC simulations range modulation effects of lung tissue were observed. The determined modulation powers showed a great range from 0.05 mm, in the micro-CT data, to 0.7 mm in the lung measurements. The SOBP comparison showed that range modulation effects Result in over- and underdosages at the distal and proximal edge of the SOBP. In the investigated case, the last 0.5 cm of the SOBP showed an underdosage of up to 50% at the distal edge, while 0.5 cm distal to the SOBP an overdosage of up to 50% was observed. Conclusion: Range modulation effects occur in inhomogeneous materials like lung. These modulation effects may Result in clinically relevant over- and underdosages but are currently not considered in commercially available treatment planning systems.« less

Dynamic range in BOLD modulation: lifespan aging trajectories and association with performance.

PubMed

Kennedy, Kristen M; Boylan, Maria A; Rieck, Jenny R; Foster, Chris M; Rodrigue, Karen M

2017-12-01

Alteration of dynamic range of modulation to cognitive difficulty has been proposed as a salient predictor of cognitive aging. Here, we examine in 171 adults (aged 20-94 years) the effects of age on dynamic modulation of blood oxygenation-level dependent activation to difficulty in parametrically increasing working memory (WM) load (0-, 2-, 3-, and 4-back conditions). First, we examined parametric increases and decreases in activation to increasing WM load (positive modulation effect and negative modulation effect). Second, we examined the effect of age on modulation to difficulty (WM load) to identify regions that differed with age as difficulty increased (age-related positive and negative modulation effects). Weakened modulation to difficulty with age was found in both the positive modulation (middle frontal, superior/inferior parietal) and negative modulation effect (deactivated) regions (insula, cingulate, medial superior frontal, fusiform, and parahippocampal gyri, hippocampus, and lateral occipital cortex). Age-related alterations to positive modulation emerged later in the lifespan than negative modulation. Furthermore, these effects were significantly coupled in that greater upmodulation was associated with lesser downmodulation. Importantly, greater fronto-parietal upmodulation to difficulty and greater downmodulation of deactivated regions were associated with better task accuracy and upmodulation with better WM span measured outside the scanner. These findings suggest that greater dynamic range of modulation of activation to cognitive challenge is in service of current task performance, as well as generalizing to cognitive ability beyond the scanner task, lending support to its utility as a marker of successful cognitive aging. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of synthetic jet modulation schemes on the reduction of a laminar separation bubble

NASA Astrophysics Data System (ADS)

Seo, J. H.; Cadieux, F.; Mittal, R.; Deem, E.; Cattafesta, L.

2018-03-01

The response of a laminar separation bubble to synthetic jet forcing with various modulation schemes is investigated via direct numerical simulations. A simple sinusoidal waveform is considered as a reference case, and various amplitude modulation schemes, including the square-wave "burst" modulation, are employed in the simulations. The results indicate that burst modulation is less effective at reducing the length of the flow separation than the sinusoidal forcing primarily because burst modulation is associated with a broad spectrum of input frequencies that are higher than the target frequency for the flow control. It is found that such high-frequency forcing delays vortex roll-up and promotes vortex pairing and merging, which have an adverse effect on reducing the separation bubble length. A commonly used amplitude modulation scheme is also found to have reduced effectiveness due to its spectral content. A new amplitude modulation scheme which is tailored to impart more energy at the target frequency is proposed and shown to be more effective than the other modulation schemes. Experimental measurements confirm that modulation schemes can be preserved through the actuator and used to enhance the energy content at the target modulation frequency. The present study therefore suggests that the effectiveness of synthetic jet-based flow control could be improved by carefully designing the spectral content of the modulation scheme.

Bridging the gap between modules in isolation and as part of networks: A systems framework for elucidating interaction and regulation of signalling modules

NASA Astrophysics Data System (ADS)

Menon, Govind; Krishnan, J.

2016-07-01

While signalling and biochemical modules have been the focus of numerous studies, they are typically studied in isolation, with no examination of the effects of the ambient network. In this paper we formulate and develop a systems framework, rooted in dynamical systems, to understand such effects, by studying the interaction of signalling modules. The modules we consider are (i) basic covalent modification, (ii) monostable switches, (iii) bistable switches, (iv) adaptive modules, and (v) oscillatory modules. We systematically examine the interaction of these modules by analyzing (a) sequential interaction without shared components, (b) sequential interaction with shared components, and (c) oblique interactions. Our studies reveal that the behaviour of a module in isolation may be substantially different from that in a network, and explicitly demonstrate how the behaviour of a given module, the characteristics of the ambient network, and the possibility of shared components can result in new effects. Our global approach illuminates different aspects of the structure and functioning of modules, revealing the importance of dynamical characteristics as well as biochemical features; this provides a methodological platform for investigating the complexity of natural modules shaped by evolution, elucidating the effects of ambient networks on a module in multiple cellular contexts, and highlighting the capabilities and constraints for engineering robust synthetic modules. Overall, such a systems framework provides a platform for bridging the gap between non-linear information processing modules, in isolation and as parts of networks, and a basis for understanding new aspects of natural and engineered cellular networks.

Bridging the gap between modules in isolation and as part of networks: A systems framework for elucidating interaction and regulation of signalling modules.

PubMed

Menon, Govind; Krishnan, J

2016-07-21

While signalling and biochemical modules have been the focus of numerous studies, they are typically studied in isolation, with no examination of the effects of the ambient network. In this paper we formulate and develop a systems framework, rooted in dynamical systems, to understand such effects, by studying the interaction of signalling modules. The modules we consider are (i) basic covalent modification, (ii) monostable switches, (iii) bistable switches, (iv) adaptive modules, and (v) oscillatory modules. We systematically examine the interaction of these modules by analyzing (a) sequential interaction without shared components, (b) sequential interaction with shared components, and (c) oblique interactions. Our studies reveal that the behaviour of a module in isolation may be substantially different from that in a network, and explicitly demonstrate how the behaviour of a given module, the characteristics of the ambient network, and the possibility of shared components can result in new effects. Our global approach illuminates different aspects of the structure and functioning of modules, revealing the importance of dynamical characteristics as well as biochemical features; this provides a methodological platform for investigating the complexity of natural modules shaped by evolution, elucidating the effects of ambient networks on a module in multiple cellular contexts, and highlighting the capabilities and constraints for engineering robust synthetic modules. Overall, such a systems framework provides a platform for bridging the gap between non-linear information processing modules, in isolation and as parts of networks, and a basis for understanding new aspects of natural and engineered cellular networks.

Estimating the Effects of Module Area on Thin-Film Photovoltaic System Costs: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horowitz, Kelsey A; Fu, Ran; Silverman, Timothy J

We investigate the potential effects of module area on the cost and performance of photovoltaic systems. Applying a bottom-up methodology, we analyzed the costs associated with thin-film modules and systems as a function of module area. We calculate a potential for savings of up to 0.10 dollars/W and 0.13 dollars/W in module manufacturing costs for CdTe and CIGS respectively, with large area modules. We also find that an additional 0.04 dollars/W savings in balance-of-systems costs may be achieved. Sensitivity of the dollar/W cost savings to module efficiency, manufacturing yield, and other parameters is presented. Lifetime energy yield must also bemore » maintained to realize reductions in the levelized cost of energy; the effects of module size on energy yield for monolithic thin-film modules are not yet well understood. Finally, we discuss possible non-cost barriers to adoption of large area modules.« less

Design and Implementation of a Cooperative Learning System for Digital Content Design Curriculum: Investigation on Learning Effectiveness and Social Presence

ERIC Educational Resources Information Center

Huang, Ming-Shang; Hsiao, Wei-Hung; Chang, Tsung-Sheng; Hu, Mei-Huei

2012-01-01

The purpose of this paper is to investigate the learning effectiveness of cooperative learning system based on social presence theory. We develop a web-based cooperative learning system which contains personal module, admin module, course module, communication module, and learning records module to support the implementation of cooperative…

Aging and sequential modulations of poorer strategy effects: An EEG study in arithmetic problem solving.

PubMed

Hinault, Thomas; Lemaire, Patrick; Phillips, Natalie

2016-01-01

This study investigated age-related differences in electrophysiological signatures of sequential modulations of poorer strategy effects. Sequential modulations of poorer strategy effects refer to decreased poorer strategy effects (i.e., poorer performance when the cued strategy is not the best) on current problem following poorer strategy problems compared to after better strategy problems. Analyses on electrophysiological (EEG) data revealed important age-related changes in time, frequency, and coherence of brain activities underlying sequential modulations of poorer strategy effects. More specifically, sequential modulations of poorer strategy effects were associated with earlier and later time windows (i.e., between 200- and 550 ms and between 850- and 1250 ms). Event-related potentials (ERPs) also revealed an earlier onset in older adults, together with more anterior and less lateralized activations. Furthermore, sequential modulations of poorer strategy effects were associated with theta and alpha frequencies in young adults while these modulations were found in delta frequency and theta inter-hemispheric coherence in older adults, consistent with qualitatively distinct patterns of brain activity. These findings have important implications to further our understanding of age-related differences and similarities in sequential modulations of cognitive control processes during arithmetic strategy execution. Copyright © 2015 Elsevier B.V. All rights reserved.

Numerical investigation of output beam quality in efficient broadband optical parametric chirped pulse amplification

NASA Astrophysics Data System (ADS)

Liu, Xiao-Di; Xu, Lu; Liang, Xiao-Yan

2017-01-01

We theoretically analyzed output beam quality of broad bandwidth non-collinear optical parametric chirped pulse amplification (NOPCPA) in LiB3O5 (LBO) centered at 800 nm. With a three-dimensional numerical model, the influence of the pump intensity, pump and signal spatial modulations, and the walk-off effect on the OPCPA output beam quality are presented, together with conversion efficiency and the gain spectrum. The pump modulation is a dominant factor that affects the output beam quality. Comparatively, the influence of signal modulation is insignificant. For a low-energy system with small beam sizes, walk-off effect has to be considered. Pump modulation and walk-off effect lead to asymmetric output beam profile with increased modulation. A special pump modulation type is found to optimize output beam quality and efficiency. For a high-energy system with large beam sizes, the walk-off effect can be neglected, certain back conversion is beneficial to reduce the output modulation. A trade-off must be made between the output beam quality and the conversion efficiency, especially when the pump modulation is large since. A relatively high conversion efficiency and a low output modulation are both achievable by controlling the pump modulation and intensity.

Suggestibility and suggestive modulation of the Stroop effect.

PubMed

Kirsch, Irving

2011-06-01

Although the induction of a hypnotic state does not seem necessary for suggestive modulation of the Stroop effect, this important phenomenon has seemed to be dependent on the subject's level of hypnotic suggestibility. Raz and Campbell's (2011) study indicates that suggestion can modulate the Stroop effect substantially in very low suggestible subjects, as well as in those who are highly suggestible. This finding casts doubt on the presumed mechanism by which suggestive modulation is brought about. Research aimed at uncovering the means by which low suggestible individuals are able to modulate the Stroop effect would be welcome, as would assessment of this effect in moderately suggestible people. Copyright © 2010 Elsevier Inc. All rights reserved.

Receiver bandwidth effects on complex modulation and detection using directly modulated lasers.

PubMed

Yuan, Feng; Che, Di; Shieh, William

2016-05-01

Directly modulated lasers (DMLs) have long been employed for short- and medium-reach optical communications due to their low cost. Recently, a new modulation scheme called complex modulated DMLs has been demonstrated showing a significant optical signal to noise ratio sensitivity enhancement compared with the traditional intensity-only detection scheme. However, chirp-induced optical spectrum broadening is inevitable in complex modulated systems, which may imply a need for high-bandwidth receivers. In this Letter, we study the impact of receiver bandwidth effects on the performance of complex modulation and coherent detection systems based on DMLs. We experimentally demonstrate that such systems exhibit a reasonable tolerance for the reduced receiver bandwidth. For 10 Gbaud 4-level pulse amplitude modulation signals, the required electrical bandwidth is as low as 8.5 and 7.5 GHz for 7% and 20% forward error correction, respectively. Therefore, it is feasible to realize DML-based complex modulated systems using cost-effective receivers with narrow bandwidth.

Network analysis of the genomic basis of the placebo effect

PubMed Central

Wang, Rui-Sheng; Hall, Kathryn T.; Giulianini, Franco; Passow, Dani; Kaptchuk, Ted J.

2017-01-01

The placebo effect is a phenomenon in which patients who are given an inactive treatment (e.g., inert pill) show a perceived or actual improvement in a medical condition. Placebo effects in clinical trials have been investigated for many years especially because placebo treatments often serve as the control arm of randomized clinical trial designs. Recent observations suggest that placebo effects may be modified by genetics. This observation has given rise to the term “placebome,” which refers to a group of genome-related mediators that affect an individual’s response to placebo treatments. In this study, we conduct a network analysis of the placebome and identify a placebome module in the comprehensive human interactome using a seed-connector algorithm. The placebome module is significantly enriched with neurotransmitter signaling pathways and brain-specific proteins. We validate the placebome module using a large cohort of the Women’s Genome Health Study (WGHS) trial and demonstrate that the placebome module is significantly enriched with genes whose SNPs modify the outcome in the placebo arm of the trial. To gain insights into placebo effects in different diseases and drug treatments, we use a network proximity measure to examine the closeness of the placebome module to different disease modules and drug target modules. The results demonstrate that the network proximity of the placebome module to disease modules in the interactome significantly correlates with the strength of the placebo effect in the corresponding diseases. The proximity of the placebome module to molecular pathways affected by certain drug classes indicates the existence of placebo-drug interactions. This study is helpful for understanding the molecular mechanisms mediating the placebo response, and sets the stage for minimizing its effects in clinical trials and for developing therapeutic strategies that intentionally engage it. PMID:28570268

Features of anti-inflammatory effects of modulated extremely high-frequency electromagnetic radiation.

PubMed

Gapeyev, Andrew B; Mikhailik, Elena N; Chemeris, Nikolay K

2009-09-01

Using a model of acute zymosan-induced paw edema in NMRI mice, we test the hypothesis that anti-inflammatory effects of extremely high-frequency electromagnetic radiation (EHF EMR) can be essentially modified by application of pulse modulation with certain frequencies. It has been revealed that a single exposure of animals to continuous EHF EMR for 20 min reduced the exudative edema of inflamed paw on average by 19% at intensities of 0.1-0.7 mW/cm(2) and frequencies from the range of 42.2-42.6 GHz. At fixed effective carrier frequency of 42.2 GHz, the anti-inflammatory effect of EHF EMR did not depend on modulation frequencies, that is, application of different modulation frequencies from the range of 0.03-100 Hz did not lead to considerable changes in the effect level. On the contrary, at "ineffective" carrier frequencies of 43.0 and 61.22 GHz, the use of modulation frequencies of 0.07-0.1 and 20-30 Hz has allowed us to restore the effect up to a maximal level. The results obtained show the critical dependence of anti-inflammatory action of low-intensity EHF EMR on carrier and modulation frequencies. Within the framework of this study, the possibility of changing the level of expected biological effect of modulated EMR by a special selection of combination of carrier and modulation frequencies is confirmed.

Aging effects on DNA methylation modules in human brain and blood tissue

PubMed Central

2012-01-01

Background Several recent studies reported aging effects on DNA methylation levels of individual CpG dinucleotides. But it is not yet known whether aging-related consensus modules, in the form of clusters of correlated CpG markers, can be found that are present in multiple human tissues. Such a module could facilitate the understanding of aging effects on multiple tissues. Results We therefore employed weighted correlation network analysis of 2,442 Illumina DNA methylation arrays from brain and blood tissues, which enabled the identification of an age-related co-methylation module. Module preservation analysis confirmed that this module can also be found in diverse independent data sets. Biological evaluation showed that module membership is associated with Polycomb group target occupancy counts, CpG island status and autosomal chromosome location. Functional enrichment analysis revealed that the aging-related consensus module comprises genes that are involved in nervous system development, neuron differentiation and neurogenesis, and that it contains promoter CpGs of genes known to be down-regulated in early Alzheimer's disease. A comparison with a standard, non-module based meta-analysis revealed that selecting CpGs based on module membership leads to significantly increased gene ontology enrichment, thus demonstrating that studying aging effects via consensus network analysis enhances the biological insights gained. Conclusions Overall, our analysis revealed a robustly defined age-related co-methylation module that is present in multiple human tissues, including blood and brain. We conclude that blood is a promising surrogate for brain tissue when studying the effects of age on DNA methylation profiles. PMID:23034122

Accumulation effects in modulation spectroscopy with high-repetition-rate pulses: Recursive solution of optical Bloch equations

NASA Astrophysics Data System (ADS)

Osipov, Vladimir Al.; Pullerits, Tõnu

2017-10-01

Application of the phase-modulated pulsed light for advance spectroscopic measurements is the area of growing interest. The phase modulation of the light causes modulation of the signal. Separation of the spectral components of the modulations allows to distinguish the contributions of various interaction pathways. The lasers with high repetition rate used in such experiments can lead to appearance of the accumulation effects, which become especially pronounced in systems with long-living excited states. Recently it was shown that such accumulation effects can be used to evaluate parameters of the dynamical processes in the material. In this work we demonstrate that the accumulation effects are also important in the quantum characteristics measurements provided by modulation spectroscopy. In particular, we consider a model of quantum two-level system driven by a train of phase-modulated light pulses, organized in analogy with the two-dimensional spectroscopy experiments. We evaluate the harmonics' amplitudes in the fluorescent signal and calculate corrections appearing from the accumulation effects. We show that the corrections can be significant and have to be taken into account at analysis of experimental data.

Effect of Career Education Module on Career Development of Community College Students

ERIC Educational Resources Information Center

Talib, Jasmi A.; Salleh, Amla; Amat, Salleh; Ghavifekr, Simin; Ariff, Azlinda M.

2015-01-01

Using a pre-post and control group design, we examined the effect of a career education module on career development among a group of 122 community college students in Malaysia. The effect of gender and the interaction effect of gender and career education module on career development were also investigated. MANOVA analyses showed significant…

Analysis of multiple internal reflections in a parallel aligned liquid crystal on silicon SLM.

PubMed

Martínez, José Luis; Moreno, Ignacio; del Mar Sánchez-López, María; Vargas, Asticio; García-Martínez, Pascuala

2014-10-20

Multiple internal reflection effects on the optical modulation of a commercial reflective parallel-aligned liquid-crystal on silicon (PAL-LCoS) spatial light modulator (SLM) are analyzed. The display is illuminated with different wavelengths and different angles of incidence. Non-negligible Fabry-Perot (FP) effect is observed due to the sandwiched LC layer structure. A simplified physical model that quantitatively accounts for the observed phenomena is proposed. It is shown how the expected pure phase modulation response is substantially modified in the following aspects: 1) a coupled amplitude modulation, 2) a non-linear behavior of the phase modulation, 3) some amount of unmodulated light, and 4) a reduction of the effective phase modulation as the angle of incidence increases. Finally, it is shown that multiple reflections can be useful since the effect of a displayed diffraction grating is doubled on a beam that is reflected twice through the LC layer, thus rendering gratings with doubled phase modulation depth.

Electro-Optic Modulator and Method

DTIC Science & Technology

An optical intensity modulator which uses a Sagnac interferometer having an electro - optic phase modulator therein. An electric modulation signal is...modulating the optical signals by the electrical signal, the electro - optic effect in the modulator phase shifts the optical signals with respect to one another

Basic characteristics of high-frequency Stark-effect modulation of CO2 lasers.

NASA Technical Reports Server (NTRS)

Claspy, P. C.; Pao, Y. H.

1971-01-01

The molecular Stark effect and its application to the modulation of infrared laser radiation have been investigated both theoretically and experimentally. Using a density matrix approach, a quantum mechanical description of the effect of a time-varying electric field on the absorption coefficient and refractive index of a molecular gas near an absorption line has been formulated. For modulation applications a quantity known as the ?modulation depth' is of prime importance. Theoretical expressions for the frequency dependence of the modulation depth show that the response to the frequency of a time-varying Stark field is separated into a nondispersive and a dispersive region, depending on whether the modulating frequency is less than or greater than the homogeneous absorption linewidth. Experimental results showing nondispersive modulation at frequencies to 30 MHz are presented. In addition it is shown that the response of modulation depth to Stark field amplitude is separated into linear and nonlinear regions, the field at which nonlinearities begin being determined by the absorption spectrum of the molecule being used.

[Pulse-modulated Electromagnetic Radiation of Extremely High Frequencies Protects Cellular DNA against Damaging Effect of Physico-Chemical Factors in vitro].

PubMed

Gapeyev, A B; Lukyanova, N A

2015-01-01

Using a comet assay technique, we investigated protective effects of. extremely high frequency electromagnetic radiation in combination with the damaging effect of X-ray irradiation, the effect of damaging agents hydrogen peroxide and methyl methanesulfonate on DNA in mouse whole blood leukocytes. It was shown that the preliminary exposure of the cells to low intensity pulse-modulated electromagnetic radiation (42.2 GHz, 0.1 mW/cm2, 20-min exposure, modulation frequencies of 1 and 16 Hz) caused protective effects decreasing the DNA damage by 20-45%. The efficacy of pulse-modulated electromagnetic radiation depended on the type of genotoxic agent and increased in a row methyl methanesulfonate--X-rays--hydrogen peroxide. Continuous electromagnetic radiation was ineffective. The mechanisms of protective effects may be connected with an induction of the adaptive response by nanomolar concentrations of reactive oxygen species formed by pulse-modulated electromagnetic radiation.

Enhancing quantum effects via periodic modulations in optomechanical systems

NASA Astrophysics Data System (ADS)

Farace, Alessandro; Giovannetti, Vittorio

2012-07-01

Parametrically modulated optomechanical systems have been recently proposed as a simple and efficient setting for the quantum control of a micromechanical oscillator: relevant possibilities include the generation of squeezing in the oscillator position (or momentum) and the enhancement of entanglement between mechanical and radiation modes. In this paper we further investigate this modulation regime, considering an optomechanical system with one or more parameters being modulated over time. We first apply a sinusoidal modulation of the mechanical frequency and characterize the optimal regime in which the visibility of purely quantum effects is maximal. We then introduce a second modulation on the input laser intensity and analyze the interplay between the two. We find that an interference pattern shows up, so that different choices of the relative phase between the two modulations can either enhance or cancel the desired quantum effects, opening new possibilities for optimal quantum control strategies.

Multiplicative and additive modulation of neuronal tuning with population activity affects encoded information

PubMed Central

Arandia-Romero, Iñigo; Tanabe, Seiji; Drugowitsch, Jan; Kohn, Adam; Moreno-Bote, Rubén

2016-01-01

Numerous studies have shown that neuronal responses are modulated by stimulus properties, and also by the state of the local network. However, little is known about how activity fluctuations of neuronal populations modulate the sensory tuning of cells and affect their encoded information. We found that fluctuations in ongoing and stimulus-evoked population activity in primate visual cortex modulate the tuning of neurons in a multiplicative and additive manner. While distributed on a continuum, neurons with stronger multiplicative effects tended to have less additive modulation, and vice versa. The information encoded by multiplicatively-modulated neurons increased with greater population activity, while that of additively-modulated neurons decreased. These effects offset each other, so that population activity had little effect on total information. Our results thus suggest that intrinsic activity fluctuations may act as a `traffic light' that determines which subset of neurons are most informative. PMID:26924437

Thermal and other tests of photovoltaic modules performed in natural sunlight

NASA Technical Reports Server (NTRS)

Stultz, J. W.

1979-01-01

The nominal operating cell temperature (NOCT), an effective way to characterize the thermal performance of a photovoltaic module in natural sunlight, is developed. NOCT measurements for more than twenty different modules are presented. Changes in NOCT reflect changes in module design, residential roof mounting, and dirt accumulation. Other test results show that electrical performance is improved by cooling modules with water and by use of a phase change wax. Electrical degradation resulting from the marriage of photovoltaic and solar water heating modules is demonstrated. Cost-effectiveness of each of these techniques is evaluated.

Negative Emotion Does Not Modulate Rapid Feature Integration Effects

PubMed Central

Trübutschek, Darinka; Egner, Tobias

2012-01-01

Emotional arousal at encoding is known to facilitate later memory recall. In the present study, we asked whether this emotion-modulation of episodic memory is also evident at very short time scales, as measured by “feature integration effects,” the moment-by-moment binding of relevant stimulus and response features in episodic memory. This question was motivated by recent findings that negative emotion appears to potentiate first-order trial sequence effects in classic conflict tasks, which has been attributed to emotion-modulation of conflict-driven cognitive control processes. However, these effects could equally well have been carried by emotion-modulation of mnemonic feature binding processes, which were perfectly confounded with putative control processes in these studies. In the present experiments, we tried to shed light on this question by testing explicitly whether feature integration processes, assessed in isolation of conflict–control, are in fact susceptible to negative emotion-modulation. For this purpose, we adopted a standard protocol for assessing the rapid binding of stimulus and response features in episodic memory (Experiment 1) and paired it with the presentation of either neutral or fearful background face stimuli, shown either at encoding only (Experiment 2), or at both encoding and retrieval (Experiment 3). Whereas reliable feature integration effects were observed in all three experiments, no evidence for emotion-modulation of these effects was detected, in spite of significant effects of emotion on response times. These findings suggest that rapid feature integration of foreground stimulus and response features is not subject to modulation by negative emotional background stimuli and further suggest that previous reports of emotion-modulated trial–transition effects are likely attributable to the effects of emotion on cognitive control processes. PMID:22509172

High extinction ratio integrated optical modulator for quantum telecommunication systems

NASA Astrophysics Data System (ADS)

Tronev, A.; Parfenov, M.; Agruzov, P.; Ilichev, I.; Shamray, A.

2018-01-01

A method for increasing the extinction ratio of integrated optical Mach-Zehnder modulators based on LiNbO3 via the photorefractive effect is proposed. The influence of the photorefractive effect on the X- and Y-splitters of intensity modulators is experimentally studied. An increase in the modulator extinction ratio by 17 dB (from 30 to 47 dB) is obtained. It is shown that fabricated modulators with a high extinction ratio are important for quantum key distribution systems.

Amplitude Modulations of Acoustic Communication Signals

NASA Astrophysics Data System (ADS)

Turesson, Hjalmar K.

2011-12-01

In human speech, amplitude modulations at 3 -- 8 Hz are important for discrimination and detection. Two different neurophysiological theories have been proposed to explain this effect. The first theory proposes that, as a consequence of neocortical synaptic dynamics, signals that are amplitude modulated at 3 -- 8 Hz are propagated better than un-modulated signals, or signals modulated above 8 Hz. This suggests that neural activity elicited by vocalizations modulated at 3 -- 8 Hz is optimally transmitted, and the vocalizations better discriminated and detected. The second theory proposes that 3 -- 8 Hz amplitude modulations interact with spontaneous neocortical oscillations. Specifically, vocalizations modulated at 3 -- 8 Hz entrain local populations of neurons, which in turn, modulate the amplitude of high frequency gamma oscillations. This suggests that vocalizations modulated at 3 -- 8 Hz should induce stronger cross-frequency coupling. Similar to human speech, we found that macaque monkey vocalizations also are amplitude modulated between 3 and 8 Hz. Humans and macaque monkeys share similarities in vocal production, implying that the auditory systems subserving perception of acoustic communication signals also share similarities. Based on the similarities between human speech and macaque monkey vocalizations, we addressed how amplitude modulated vocalizations are processed in the auditory cortex of macaque monkeys, and what behavioral relevance modulations may have. Recording single neuron activity, as well as, the activity of local populations of neurons allowed us to test both of the neurophysiological theories presented above. We found that single neuron responses to vocalizations amplitude modulated at 3 -- 8 Hz resulted in better stimulus discrimination than vocalizations lacking 3 -- 8 Hz modulations, and that the effect most likely was mediated by synaptic dynamics. In contrast, we failed to find support for the oscillation-based model proposing a coupling between 3 -- 8 Hz oscillations and gamma band amplitude. In a behavioral experiment, we found that 3 -- 8 amplitude modulations improved auditory detection in noise. In conclusion, our results suggest that, as in human speech, 3 -- 8 Hz amplitude modulations have a behaviorally important effect, and that this effect probably is mediated by synaptic dynamics.

Surface modulation of dental hard tissues

NASA Astrophysics Data System (ADS)

Tantbirojn, Daranee

Tooth surfaces play a central role in the equilibrium of dental hard tissues, in which contrasting processes lead to loss or deposition of materials. The central interest of this Thesis was the modulation of tooth surfaces to control such equilibrium. Four specific studies were carried out to investigate different classes of surface modulating agents. These are: (1) Ionic modulation of the enamel surface to enhance stain removal . Dental stain is the most apparent form of tooth surface deposit. The nature of extrinsic stain in terms of spatial chemical composition was studied by using electron probe microanalysis. An ionic surface modulating agent, sodium tripolyphosphate (STPP), was evaluated. Image analysis methodologies were developed and the ability of STPP in stain removal was proved. (2) Thin film modulation with substantive polymeric coating and the effect on in vitro enamel de/re-mineralization . A novel polymeric coating that formed a thin film on the tooth surface was investigated for its inhibitory effect on artificial enamel caries, without interfering with the remineralization process. The preventive effect was distinct, but the mineral redeposition was questionable. (3) Thick film modulation with fluoride containing sealants and the effect on in vitro enamel and root caries development. Fluoride incorporated into resin material is an example of combining different classes of surface modulating agents to achieve an optimal outcome. A proper combination, such as in resin modified glass ionomer, showed in vitro caries inhibitory effect beyond the material boundary in both enamel and dentin. (4) Thick film modulation with dental adhesives and the determination of adhesion to dentin. Dentin adhesives modulate intracoronal tooth surfaces by enhancing adhesion to restorative materials. Conventional nominal bond tests were inadequate to determine the performance of current high strength adhesives. It was shown that interfacial fracture toughness test was more appropriate. In general, this Thesis evaluates diverse tooth surface modulations, for which several experimental methodologies had to be developed. These will be invaluable for the development of succeeding generations of surface modulating agents.

Assessment of ultrasound modulation of near infrared light on the quantification of scattering coefficient.

PubMed

Singh, M Suheshkumar; Yalavarthy, Phaneendra K; Vasu, R M; Rajan, K

2010-07-01

To assess the effect of ultrasound modulation of near infrared (NIR) light on the quantification of scattering coefficient in tissue-mimicking biological phantoms. A unique method to estimate the phase of the modulated NIR light making use of only time averaged intensity measurements using a charge coupled device camera is used in this investigation. These experimental measurements from tissue-mimicking biological phantoms are used to estimate the differential pathlength, in turn leading to estimation of optical scattering coefficient. A Monte-Carlo model based numerical estimation of phase in lieu of ultrasound modulation is performed to verify the experimental results. The results indicate that the ultrasound modulation of NIR light enhances the effective scattering coefficient. The observed effective scattering coefficient enhancement in tissue-mimicking viscoelastic phantoms increases with increasing ultrasound drive voltage. The same trend is noticed as the ultrasound modulation frequency approaches the natural vibration frequency of the phantom material. The contrast enhancement is less for the stiffer (larger storage modulus) tissue, mimicking tumor necrotic core, compared to the normal tissue. The ultrasound modulation of the insonified region leads to an increase in the effective number of scattering events experienced by NIR light, increasing the measured phase, causing the enhancement in the effective scattering coefficient. The ultrasound modulation of NIR light could provide better estimation of scattering coefficient. The observed local enhancement of the effective scattering coefficient, in the ultrasound focal region, is validated using both experimental measurements and Monte-Carlo simulations.

Modulation-Frequency-Specific Adaptation in Awake Auditory Cortex

PubMed Central

Beitel, Ralph E.; Vollmer, Maike; Heiser, Marc A.; Schreiner, Christoph E.

2015-01-01

Amplitude modulations are fundamental features of natural signals, including human speech and nonhuman primate vocalizations. Because natural signals frequently occur in the context of other competing signals, we used a forward-masking paradigm to investigate how the modulation context of a prior signal affects cortical responses to subsequent modulated sounds. Psychophysical “modulation masking,” in which the presentation of a modulated “masker” signal elevates the threshold for detecting the modulation of a subsequent stimulus, has been interpreted as evidence of a central modulation filterbank and modeled accordingly. Whether cortical modulation tuning is compatible with such models remains unknown. By recording responses to pairs of sinusoidally amplitude modulated (SAM) tones in the auditory cortex of awake squirrel monkeys, we show that the prior presentation of the SAM masker elicited persistent and tuned suppression of the firing rate to subsequent SAM signals. Population averages of these effects are compatible with adaptation in broadly tuned modulation channels. In contrast, modulation context had little effect on the synchrony of the cortical representation of the second SAM stimuli and the tuning of such effects did not match that observed for firing rate. Our results suggest that, although the temporal representation of modulated signals is more robust to changes in stimulus context than representations based on average firing rate, this representation is not fully exploited and psychophysical modulation masking more closely mirrors physiological rate suppression and that rate tuning for a given stimulus feature in a given neuron's signal pathway appears sufficient to engender context-sensitive cortical adaptation. PMID:25878263

Vulnerability of Space Station Freedom Modules: A Study of the Effects of Module Perforation on Crew and Equipment. Volume 2; Analytical Modeling of Internal Debris Cloud Effects

NASA Technical Reports Server (NTRS)

Schonberg, William P.; Davenport, Quint

1995-01-01

In this part of the report, a first-principles based model is developed to predict the overpressure and temperature effects of a perforating orbital debris particle impact within a pressurized habitable module. While the effects of a perforating debris particles on crew and equipment can be severe, only a limited number of empirical studies focusing on space vehicles have been performed to date. Traditionally, crew loss or incapacitation due to a perforating impact has primarily been of interest to military organizations and as such have focused on military vehicles and systems. The module wall considered in this study is initially assumed to be a standard Whippletype dual-wall system in which the outer wall protects the module and its inhabitants by disrupting impacting particles. The model is developed in a way such that it sequentially characterizes the phenomena comprising the impact event, including the initial impact, the creation and motion of a debris cloud within the dual-wall system, the impact of the debris cloud on the inner wall, the creation and motion of the debris cloud that enters the module interior, and the effects of the debris cloud within the module on module pressure and temperature levels. This is accomplished through the application of elementary shock physics and thermodynamic theory.

GABAA receptor positive allosteric modulators modify the abuse-related behavioral and neurochemical effects of methamphetamine in rhesus monkeys.

PubMed

Berro, Laís F; Andersen, Monica L; Tufik, Sergio; Howell, Leonard L

2017-09-01

GABA A receptor positive allosteric modulators (GABA A receptor modulators) are commonly used for the treatment of insomnia. Nevertheless, the effects of these compounds on psychostimulant-induced sleep impairment are poorly understood. Because GABA A receptor modulators have been shown to decrease the abuse-related effects of psychostimulants, the aim of the present study was to evaluate the effects of temazepam (0.3, 1.0 or 3.0 mg/kg) and eszopiclone (0.3, 1.0 or 3.0 mg/kg), two GABA A receptor modulators, on the behavioral neuropharmacology of methamphetamine in adult rhesus macaques (n = 5). Sleep-like measures and general daytime activity were evaluated with Actiwatch monitors. Methamphetamine self-administration (0.03 mg/kg/inf) was evaluated during morning sessions. Methamphetamine-induced dopamine overflow was assessed through in vivo microdialysis targeting the nucleus accumbens. Nighttime treatment with either temazepam or eszopiclone was ineffective in improving sleep-like measures disrupted by methamphetamine self-administration. Acute pretreatment with a low dose of temazepam before self-administration sessions increased methamphetamine self-administration without affecting normal daytime home-cage activity. At a high dose, acute temazepam pretreatment decreased methamphetamine self-administration and attenuated methamphetamine-induced increases in dopamine in the nucleus accumbens, without decreasing general daytime activity. Acute eszopiclone treatment exerted no effects on methamphetamine intake or drug-induced increases in dopamine. Our study suggests that treatments based on GABA A receptor modulators are not effective for the treatment of sleep disruption in the context of psychostimulant use. In addition, distinct GABA A receptor modulators differentially modulated the abuse-related effects of methamphetamine, with acute treatment with the high efficacy GABA A receptor modulator temazepam decreasing the behavioral and neurochemical effects of methamphetamine. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of estrogen receptor modulators on cytoskeletal proteins in the central nervous system.

PubMed

Segura-Uribe, Julia J; Pinto-Almazán, Rodolfo; Coyoy-Salgado, Angélica; Fuentes-Venado, Claudia E; Guerra-Araiza, Christian

2017-08-01

Estrogen receptor modulators are compounds of interest because of their estrogenic agonistic/antagonistic effects and tissue specificity. These compounds have many clinical applications, particularly for breast cancer treatment and osteoporosis in postmenopausal women, as well as for the treatment of climacteric symptoms. Similar to estrogens, neuroprotective effects of estrogen receptor modulators have been described in different models. However, the mechanisms of action of these compounds in the central nervous system have not been fully described. We conducted a systematic search to investigate the effects of estrogen receptor modulators in the central nervous system, focusing on the modulation of cytoskeletal proteins. We found that raloxifene, tamoxifen, and tibolone modulate some cytoskeletal proteins such as tau, microtuble-associated protein 1 (MAP1), MAP2, neurofilament 38 (NF38) by different mechanisms of action and at different levels: neuronal microfilaments, intermediate filaments, and microtubule-associated proteins. Finally, we emphasize the importance of the study of these compounds in the treatment of neurodegenerative diseases since they present the benefits of estrogens without their side effects.

Effects of estrogen receptor modulators on cytoskeletal proteins in the central nervous system

PubMed Central

Segura-Uribe, Julia J.; Pinto-Almazán, Rodolfo; Coyoy-Salgado, Angélica; Fuentes-Venado, Claudia E.; Guerra-Araiza, Christian

2017-01-01

Estrogen receptor modulators are compounds of interest because of their estrogenic agonistic/antagonistic effects and tissue specificity. These compounds have many clinical applications, particularly for breast cancer treatment and osteoporosis in postmenopausal women, as well as for the treatment of climacteric symptoms. Similar to estrogens, neuroprotective effects of estrogen receptor modulators have been described in different models. However, the mechanisms of action of these compounds in the central nervous system have not been fully described. We conducted a systematic search to investigate the effects of estrogen receptor modulators in the central nervous system, focusing on the modulation of cytoskeletal proteins. We found that raloxifene, tamoxifen, and tibolone modulate some cytoskeletal proteins such as tau, microtuble-associated protein 1 (MAP1), MAP2, neurofilament 38 (NF38) by different mechanisms of action and at different levels: neuronal microfilaments, intermediate filaments, and microtubule-associated proteins. Finally, we emphasize the importance of the study of these compounds in the treatment of neurodegenerative diseases since they present the benefits of estrogens without their side effects. PMID:28966632

Acupuncture induce the different modulation patterns of the default mode network: an fMRI study

NASA Astrophysics Data System (ADS)

Liu, Peng; Qin, Wei; Tian, Jie; Zhang, Yi

2009-02-01

According to Traditional Chinese Medicine (TCM) theory and certain clinical treatment reports, the sustained effects of acupuncture indeed exist, which may last several minutes or hours. Furthermore, increased attention has fallen on the sustained effects of acupuncture. Recently, it is reported that the sustained acupuncture effects may alter the default mode network (DMN). It raises interesting questions: whether the modulations of acupuncture effects to the DMN are still detected at other acupoints and whether the modulation patterns are different induced by different acupoints. In the present study, we wanted to investigate the questions. An experiment fMRI design was carried out on 36 subjects with the electroacupuncture stimulation (EAS) at the three acupoints: Guangming (GB37), Kunlun (BL60) and Jiaoxin (KI8) on the left leg. The data sets were analyzed by a data driven method named independent component analysis (ICA). The results indicated that the three acupoints stimulations may modulate the DMN. Moreover, the modulation patterns were distinct. We suggest the different modulation patterns on the DMN may attribute to the distinct functional effects of acupoints.

Effects of the GABAB Receptor-Positive Modulators CGP7930 and rac-BHFF in Baclofen- and γ-Hydroxybutyrate-Discriminating Pigeons

PubMed Central

France, Charles P.; Cheng, Kejun; Rice, Kenner C.

2012-01-01

In vivo effects of GABAB receptor-positive modulators suggest them to have therapeutic potential to treat central nervous system disorders such as anxiety and drug abuse. Although these effects are thought to be mediated by positive modulation of GABAB receptors, such modulation has been examined primarily in vitro. This study further examined the in vivo properties of the GABAB receptor-positive modulators 2,6-di-tert-butyl-4-(3-hydroxy-2,2-dimethylpropyl) phenol (CGP7930) and (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one (rac-BHFF). In pigeons discriminating baclofen from saline, γ-hydroxybutyrate (GHB) produced 100% baclofen-appropriate responding, and the GABAB antagonist 3-aminopropyl(dimethoxymethyl) phosphinic acid (CGP35348) blocked the effects of both drugs. CGP7930 and rac-BHFF produced at most 41 and 74% baclofen-appropriate responding, respectively, and enhanced the discriminative stimulus effects of baclofen, but not of GHB. In pigeons discriminating GHB from saline, CGP7930 and rac-BHFF produced at most 1 and 49% GHB-appropriate responding, respectively, and enhanced the effects of baclofen, but not of GHB. Enhancement of the discriminative stimulus effects of baclofen by rac-BHFF and CGP7930 is further evidence of their effectiveness as GABAB receptor-positive modulators in vivo. Furthermore, lack of complete substitution of the positive modulators rac-BHFF and CGP7930 for baclofen and GHB suggests that their discriminative stimulus effects differ from those of GABAB receptor agonists. Finally, together with converging evidence that the GABAB receptor populations mediating the effects of baclofen and GHB are not identical, the present findings suggest that these populations differ in their susceptibility to positive modulatory effects. Such differences could allow for more selective therapeutic targeting of the GABAB system. PMID:22319197

The Effect of Specific Training And Intervention Upon The Performance Of Classroom Teacher Collaboration Activity In Teacher Education.

ERIC Educational Resources Information Center

Smith, Howard W., Jr.

This report evaluates the effectiveness of a module for classroom teachers. The development of this module was an attempt to assist teachers in functioning more effectively in the education decision making process. This module focused on teacher participation and roles in teacher education programs and gave special attention to competency based…

Cystic fibrosis transmembrane conductance regulator modulators: precision medicine in cystic fibrosis.

PubMed

Burgener, Elizabeth B; Moss, Richard B

2018-06-01

The aim of this study was to describe the newest development in cystic fibrosis (CF) care, CF transmembrane conductance regulator (CFTR) modulator therapies. Phase II results showing CFTR modulator triple therapies are more effective than current CFTR modulators. CFTR modulator therapy targets the protein defective in CF and boosts its function, but the drug must match mutation pathobiology. Ivacaftor, a CFTR potentiator, was the first modulator approved in 2012, with impressive improvement in lung function and other measures of disease in patients with gating and other residual function mutations (∼10% of CF patients). In 2015, the combination of lumacaftor, a CFTR corrector, and ivacaftor was approved for patients homozygous for the F508del mutation (∼40-50% of the CF population) with positive but less impressive clinical response and 10-20% incidence of intolerance. A next-generation CFTR corrector, tezacaftor, with ivacaftor equally effective and better tolerated than lumacaftor, has also received US Food and Drug Administration approval. Novel CFTR correctors, entering Phase 3 trials in triple modulator combination with tezacaftor-ivacaftor, appear substantially more effective for patients who are homozygous for the F508del mutation and can provide benefit for patients with a single F508del mutation. This offers promise of effective CFTR modulator therapy for nearly 90% of CF patients.

Comparing the effects of age on amplitude modulation and frequency modulation detection.

PubMed

Wallaert, Nicolas; Moore, Brian C J; Lorenzi, Christian

2016-06-01

Frequency modulation (FM) and amplitude modulation (AM) detection thresholds were measured at 40 dB sensation level for young (22-28 yrs) and older (44-66 yrs) listeners with normal audiograms for a carrier frequency of 500 Hz and modulation rates of 2 and 20 Hz. The number of modulation cycles, N, varied between 2 and 9. For FM detection, uninformative AM at the same rate as the FM was superimposed to disrupt excitation-pattern cues. For both groups, AM and FM detection thresholds were lower for the 2-Hz than for the 20-Hz rate, and AM and FM detection thresholds decreased with increasing N. Thresholds were higher for older than for younger listeners, especially for FM detection at 2 Hz, possibly reflecting the effect of age on the use of temporal-fine-structure cues for 2-Hz FM detection. The effect of increasing N was similar across groups for both AM and FM. However, at 20 Hz, older listeners showed a greater effect of increasing N than younger listeners for both AM and FM. The results suggest that ageing reduces sensitivity to both excitation-pattern and temporal-fine-structure cues for modulation detection, but more so for the latter, while sparing temporal integration of these cues at low modulation rates.

Cost-effective bidirectional digitized radio-over-fiber systems employing sigma delta modulation

NASA Astrophysics Data System (ADS)

Lee, Kyung Woon; Jung, HyunDo; Park, Jung Ho

2016-11-01

We propose a cost effective digitized radio-over-fiber (D-RoF) system employing a sigma delta modulation (SDM) and a bidirectional transmission technique using phase modulated downlink and intensity modulated uplink. SDM is transparent to different radio access technologies and modulation formats, and more suitable for a downlink of wireless system because a digital to analog converter (DAC) can be avoided at the base station (BS). Also, Central station and BS share the same light source by using a phase modulation for the downlink and an intensity modulation for the uplink transmission. Avoiding DACs and light sources have advantages in terms of cost reduction, power consumption, and compatibility with conventional wireless network structure. We have designed a cost effective bidirectional D-RoF system using a low pass SDM and measured the downlink and uplink transmission performance in terms of error vector magnitude, signal spectra, and constellations, which are based on the 10MHz LTE 64-QAM standard.

Highly Sensitive Electro-Optic Modulators

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeVore, Peter S

2015-10-26

There are very important diagnostic and communication applications that receive faint electrical signals to be transmitted over long distances for capture. Optical links reduce bandwidth and distance restrictions of metal transmission lines; however, such signals are only weakly imprinted onto the optical carrier, resulting in low fidelity transmission. Increasing signal fidelity often necessitates insertion of radio-frequency (RF) amplifiers before the electro-optic modulator, but (especially at high frequencies) RF amplification results in large irreversible distortions. We have investigated the feasibility of a Sensitive and Linear Modulation by Optical Nonlinearity (SALMON) modulator to supersede RF-amplified modulators. SALMON uses cross-phase modulation, a manifestationmore » of the Kerr effect, to enhance the modulation depth of an RF-modulated optical wave. This ultrafast process has the potential to result in less irreversible distortions as compared to a RF-amplified modulator due to the broadband nature of the Kerr effect. Here, we prove that a SALMON modulator is a feasible alternative to an RFamplified modulator, by demonstrating a sensitivity enhancement factor greater than 20 and significantly reduced distortion.« less

Studies on transmitted beam modulation effect from laser induced damage on fused silica optics.

PubMed

Zheng, Yi; Ma, Ping; Li, Haibo; Liu, Zhichao; Chen, Songlin

2013-07-15

UV laser induced damage (LID) on exit surface of fused silica could cause modulation effect to transmitted beam and further influence downstream propagation properties. This paper presents our experimental and analytical studies on this topic. In experiment, a series of measurement instruments are applied, including beam profiler, interferometer, microscope, and optical coherent tomography (OCT). Creating and characterizing of LID on fused silica sample have been implemented. Morphological features are studied based on their particular modulation effects on transmitted beam. In theoretical investigation, analytical modeling and numerical simulation are performed. Modulation effects from amplitude, phase, and size factors are analyzed respectively. Furthermore, we have novelly designed a simplified polygon model to simulate actual damage site with multiform modulation features, and the simulation results demonstrate that the modeling is usable and representative.

EFFECTS OF CONTINUOUS-WAVE, PULSED, AND SINUSOIDAL-AMPLITUDE-MODULATED MICROWAVES ON BRAIN ENERGY METABOLISM

EPA Science Inventory

A comparison of the effects of continuous wave, sinusoidal-amplitude modulated, and pulsed square-wave-modulated 591-MHz microwave exposures on brain energy metabolism was made in male Sprague Dawley rats (175-225g). Brain NADH fluorescence, adensine triphosphate (ATP) concentrat...

Modulation Index Adjustment for Recovery of Pure Wavelength Modulation Spectroscopy Second Harmonic Signal Waveforms.

PubMed

Wei, Wei; Chang, Jun; Wang, Qiang; Qin, Zengguang

2017-01-15

A new technique of modulation index adjustment for pure wavelength modulation spectroscopy second harmonic signal waveforms recovery is presented. As the modulation index is a key parameter in determining the exact form of the signals generated by the technique of wavelength modulation spectroscopy, the method of modulation index adjustment is applied to recover the second harmonic signal with wavelength modulation spectroscopy. By comparing the measured profile with the theoretical profile by calculation, the relationship between the modulation index and average quantities of the scanning wavelength can be obtained. Furthermore, when the relationship is applied in the experimental setup by point-by-point modulation index modification for gas detection, the results show good agreement with the theoretical profile and signal waveform distortion (such as the amplitude modulation effect caused by diode laser) can be suppressed. Besides, the method of modulation index adjustment can be used in many other aspects which involve profile improvement. In practical applications, when the amplitude modulation effect can be neglected and the stability of the detection system is limited by the sampling rate of analog-to-digital, modulation index adjustment can be used to improve detection into softer inflection points and solve the insufficient sampling problem. As a result, measurement stability is improved by 40%.

Modulation Index Adjustment for Recovery of Pure Wavelength Modulation Spectroscopy Second Harmonic Signal Waveforms

PubMed Central

Wei, Wei; Chang, Jun; Wang, Qiang; Qin, Zengguang

2017-01-01

A new technique of modulation index adjustment for pure wavelength modulation spectroscopy second harmonic signal waveforms recovery is presented. As the modulation index is a key parameter in determining the exact form of the signals generated by the technique of wavelength modulation spectroscopy, the method of modulation index adjustment is applied to recover the second harmonic signal with wavelength modulation spectroscopy. By comparing the measured profile with the theoretical profile by calculation, the relationship between the modulation index and average quantities of the scanning wavelength can be obtained. Furthermore, when the relationship is applied in the experimental setup by point-by-point modulation index modification for gas detection, the results show good agreement with the theoretical profile and signal waveform distortion (such as the amplitude modulation effect caused by diode laser) can be suppressed. Besides, the method of modulation index adjustment can be used in many other aspects which involve profile improvement. In practical applications, when the amplitude modulation effect can be neglected and the stability of the detection system is limited by the sampling rate of analog-to-digital, modulation index adjustment can be used to improve detection into softer inflection points and solve the insufficient sampling problem. As a result, measurement stability is improved by 40%. PMID:28098842

Ultra-low power, Zeno effect based optical modulation in a degenerate V-system with a tapered nano fiber in atomic vapor.

PubMed

Salit, K; Salit, M; Krishnamurthy, Subramanian; Wang, Y; Kumar, P; Shahriar, M S

2011-11-07

We demonstrate an ultra-low light level optical modulator using a tapered nano fiber embedded in a hot rubidium vapor. The control and signal beams are co-propagating but orthogonally polarized, leading to a degenerate V-system involving coherent superpositions of Zeeman sublevels. The modulation is due primarily to the quantum Zeno effect for the signal beam induced by the control beam. For a control power of 40 nW and a signal power of 100 pW, we observe near 100% modulation. The ultra-low power level needed for the modulation is due to a combination of the Zeno effect and the extreme field localization in the evanescent field around the taper.

Heterostructure Quantum Confined Stark Effect Electrooptic Modulators Operating at 938 nm

DTIC Science & Technology

1993-12-01

type of modulator, suitable for use in optical interconnects, is an asymmetric Fabry-Perot reflection modulator (ARM). This type of an intensity ...calibrated spectrometer/diode array (Princeton Instruments Model ST-100) used in conjunction with an optical multichannel analyzer (OMA). The transmission...AD-A279 342 -" RL-TR-93-259 In -House Report December 1993N~I HETEROSTRUCTURE QUANTUM CONFINED STARK EFFECT ELECTRO- OPTIC MODULATORS OPERATING AT 938

Beam combining and SBS suppression in white noise and pseudo-random modulated amplifiers

NASA Astrophysics Data System (ADS)

Anderson, Brian; Flores, Angel; Holten, Roger; Ehrenreich, Thomas; Dajani, Iyad

2015-03-01

White noise phase modulation (WNS) and pseudo-random binary sequence phase modulation (PRBS) are effective techniques for mitigation of nonlinear effects such as stimulated Brillouin scattering (SBS); thereby paving the way for higher power narrow linewidth fiber amplifiers. However, detailed studies comparing both coherent beam combination and the SBS suppression of these phase modulation schemes have not been reported. In this study an active fiber cutback experiment is performed comparing the enhancement factor of a PRBS and WNS broadened seed as a function of linewidth and fiber length. Furthermore, two WNS and PRBS modulated fiber lasers are coherently combined to measure and compare the fringe visibility and coherence length as a function of optical path length difference. Notably, the discrete frequency comb of PRBS modulation provides a beam combining re-coherence effect where the lasers periodically come back into phase. Significantly, this may reduce path length matching complexity in coherently combined fiber laser systems.

Blind equalization and automatic modulation classification based on subspace for subcarrier MPSK optical communications

NASA Astrophysics Data System (ADS)

Chen, Dan; Guo, Lin-yuan; Wang, Chen-hao; Ke, Xi-zheng

2017-07-01

Equalization can compensate channel distortion caused by channel multipath effects, and effectively improve convergent of modulation constellation diagram in optical wireless system. In this paper, the subspace blind equalization algorithm is used to preprocess M-ary phase shift keying (MPSK) subcarrier modulation signal in receiver. Mountain clustering is adopted to get the clustering centers of MPSK modulation constellation diagram, and the modulation order is automatically identified through the k-nearest neighbor (KNN) classifier. The experiment has been done under four different weather conditions. Experimental results show that the convergent of constellation diagram is improved effectively after using the subspace blind equalization algorithm, which means that the accuracy of modulation recognition is increased. The correct recognition rate of 16PSK can be up to 85% in any kind of weather condition which is mentioned in paper. Meanwhile, the correct recognition rate is the highest in cloudy and the lowest in heavy rain condition.

Effect of modulator sorption on gradient shape in ion-exchange chromatography

NASA Technical Reports Server (NTRS)

Velayudhan, A.; Ladisch, M. R.; Mitchell, C. A. (Principal Investigator)

1995-01-01

Mobile phase additives, or modulators, are used in gradient elution chromatography to facilitate separation and reduce separation time. The modulators are usually assumed to be linearly adsorbed or unadsorbed. Here, the consequences of nonlinear modulator adsorption are examined for ion-exchange gradient elution through a series of simulations. Even when the buffer salt is identical to the modulator salt, gradient deformation is observed; the extent of deformation increases as the volume of the feed is increased. When the modulator salt is different from the buffer salt, unusual effects are observed, and the chromatograms are quite different from those predicted by classical gradient elution theory. In particular, local increases in the buffer concentration are found between feed bands, and serve to improve the separation. These effects become more pronounced as the feed volume increases, and could therefore prove valuable in preparative applications.

Observation of the Self-Modulation Instability via Time-Resolved Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gross, M.; Engel, J.; Good, J.

Self-modulation of an electron beam in a plasma has been observed. The propagation of a long (several plasma wavelengths) electron bunch in an overdense plasma resulted in the production of multiple bunches via the self-modulation instability. Using a combination of a radio-frequency deflector and a dipole spectrometer, the time and energy structure of the self-modulated beam was measured. The longitudinal phase space measurement showed the modulation of a long electron bunch into three bunches with an approximatelymore » $$200\\text{ }\\text{ }\\mathrm{keV}/c$$ amplitude momentum modulation. Demonstrating this effect is a breakthrough for proton-driven plasma accelerator schemes aiming to utilize the same physical effect.« less

Observation of the Self-Modulation Instability via Time-Resolved Measurements

DOE PAGES

Gross, M.; Engel, J.; Good, J.; ...

2018-04-06

Self-modulation of an electron beam in a plasma has been observed. The propagation of a long (several plasma wavelengths) electron bunch in an overdense plasma resulted in the production of multiple bunches via the self-modulation instability. Using a combination of a radio-frequency deflector and a dipole spectrometer, the time and energy structure of the self-modulated beam was measured. The longitudinal phase space measurement showed the modulation of a long electron bunch into three bunches with an approximatelymore » $$200\\text{ }\\text{ }\\mathrm{keV}/c$$ amplitude momentum modulation. Demonstrating this effect is a breakthrough for proton-driven plasma accelerator schemes aiming to utilize the same physical effect.« less

Classroom modules for nanotechnology undergraduate education: development, implementation and evaluation

NASA Astrophysics Data System (ADS)

Shabani, R.; Massi, L.; Zhai, L.; Seal, S.; Cho, H. J.

2011-05-01

In order to address the challenges and restrictions given by a traditional classroom lecture environment, the top-down and bottom-up nanotechnology teaching modules were developed, implemented and evaluated. Then based on the hypothesis that instructors could further develop students' interest in this emerging area through the introduction of the teaching modules and a career module, an early stage evaluation of the effectiveness of the modules in selected engineering courses was conducted. The data suggested that adoption of modular lectures in regular engineering courses influenced attitude towards nanotechnology - overall, the teaching modules did a better job of piquing student's interest (albeit in the short term) in the subject, but there were also positive gains in interest in nanotechnology as a career. There was some evidence that the hands-on demonstration teaching modules with visual elements and the career module were more effective than traditional lecture presentations in the classroom.

A Comparative Study on Selective PPAR Modulators through Quantitative Structure-activity Relationship, Pharmacophore and Docking Analyses.

PubMed

Nandy, Ashis; Roy, Kunal; Saha, Achintya

2018-01-01

Metabolic syndrome is a matrix of different metabolic disorders which are the leading cause of death in human beings. Peroxysome proliferated activated receptor (PPAR) is a nuclear receptor involved in metabolism of fats and glucose. In order to explore structural requirements for selective PPAR modulators to control lipid and carbohydrate metabolism, the multi-cheminformatics studies have been performed. In silico modeling studies have been performed on a diverse set of PPAR modulators through quantitative structure-activity relationship (QSAR), pharmacophore mapping and docking studies. It is observed that the presence of an amide fragment (-CONHRPh) has a detrimental effect while an aliphatic ether linkage has a beneficial effect on PPARα modulation. On the other hand, the presence of an amide fragment has a positive effect on PPARδ modulation, but the aliphatic ether linkage and substituted aromatic ring in the molecular scaffold are very much essential for imparting potent and selective PPARγ modulation. Negative ionizable features (i.e. polar fragments) must be present in PPARδ and α modulators, but a hydrophobic feature is the prime requirement for PPARγ modulation. Here, the essential structural features have been explored for selective modulation of each subtype of PPAR in order to design new modulators with improved activity/selectivity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Evaluation and modeling of the potential effects of a module manufacturing anomaly

DOE PAGES

Kempe, Michael D.; Jordan, Dirk C.

2017-07-13

Photovoltaic lifetime predictions are in great demand, but are exceedingly difficult to achieve with uncertainties small enough to be useful. During the construction of photovoltaic modules, small unplanned variability in materials or processes can have profound effects on module durability. Thus, continual monitoring of production quality is needed. In the subject production run, module quality, as monitored by damp heat testing, revealed a subset of modules that were prone to higher degradation rates. An assessment of the potential long-term power loss and mitigation strategies was needed. To do this, modules were exposed to variable levels of humidity and temperature withmore » periodic monitoring. The analysis takes into account the kinetics of the degradation and the spatially and temporally varying humidity content within the module during accelerated stress testing. This is an important aspect for extrapolating laboratory results to field exposure because moisture ingress is diffusion limited in most laboratory module tests but not limited in these fielded modules. This analysis predicted that although a solder flux induce degradation mechanism is significant in accelerated stress test, this is probably an artifact of a process with a very large acceleration factor that is not likely to be significant for deployed modules. The degradation mechanism affected a limited area around the tabbing helping to minimize the effect. Furthermore, three years after the system was commissioned, the fielded modules indeed show no significant power loss.« less

Evaluation and modeling of the potential effects of a module manufacturing anomaly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kempe, Michael D.; Jordan, Dirk C.

Photovoltaic lifetime predictions are in great demand, but are exceedingly difficult to achieve with uncertainties small enough to be useful. During the construction of photovoltaic modules, small unplanned variability in materials or processes can have profound effects on module durability. Thus, continual monitoring of production quality is needed. In the subject production run, module quality, as monitored by damp heat testing, revealed a subset of modules that were prone to higher degradation rates. An assessment of the potential long-term power loss and mitigation strategies was needed. To do this, modules were exposed to variable levels of humidity and temperature withmore » periodic monitoring. The analysis takes into account the kinetics of the degradation and the spatially and temporally varying humidity content within the module during accelerated stress testing. This is an important aspect for extrapolating laboratory results to field exposure because moisture ingress is diffusion limited in most laboratory module tests but not limited in these fielded modules. This analysis predicted that although a solder flux induce degradation mechanism is significant in accelerated stress test, this is probably an artifact of a process with a very large acceleration factor that is not likely to be significant for deployed modules. The degradation mechanism affected a limited area around the tabbing helping to minimize the effect. Furthermore, three years after the system was commissioned, the fielded modules indeed show no significant power loss.« less

The need for a comprehensive medication safety module in medical education.

PubMed

Chandy, Sujith John

2016-10-01

A rising number of medicines and minimal emphasis on rational prescribing in the medical curriculum may compromise medication safety. There is no focused module in the curriculum dealing with factors affecting safety such as quality, medicines management, rational use, and approach to adverse effects. Creating awareness of these issues would hopefully plant a seed of safe prescribing and encourage pharmacovigilance. A study was therefore done to determine the need for such a module. A quasi-experimental pre-post module study. Medical students ( n = 88) completing pharmacology term were recruited after informed consent. A questionnaire containing 20 questions on various themes was administered and scored. Subsequently a module was developed and relevant safety themes taught to the students. After one month, the questionnaire was re-administered. The pre module score was 9.52/20. Knowledge about the various themes, adverse effects, medication management, quality issues and rational use were similar though poor knowledge was evident in specific areas such as clinical trials, look alike-sound alike medicines (LASA) and medicine storage. The post module score was 12.24/20. The improvement of score was statistically significant suggesting the effectiveness of the module. The relatively poor knowledge and improvement with a specific educational module emphasizes the need of such a module within the medical curriculum to encourage safe use of medicines by Indian Medical Graduates (IMG). It is hoped that the policy makers in medical education will introduce such a module within the medical curriculum.

The effect of ligation method on friction in sliding mechanics.

PubMed

Hain, Max; Dhopatkar, Ashish; Rock, Peter

2003-04-01

During orthodontic tooth movement with the preadjusted edgewise system, friction generated at the bracket/archwire interface tends to impede the desired movement. The method of ligation is an important contributor to this frictional force. This in vitro study investigated the effect of ligation method on friction and evaluated the efficacy of the new slick elastomeric modules from TP Orthodontics (La Porte, Ind), which are claimed to reduce friction at the module/wire interface. Slick modules were compared with regular nonslick modules, stainless steel ligatures, and the SPEED self-ligating bracket system (Strite Industries, Cambridge, Ontario, Canada). The effect of using slick modules with metal-reinforced ceramic (Clarity, 3M Unitek, Monrovia, Calif) and miniature brackets (Minitwin, 3M Unitek) was also examined. Results showed that, when considering tooth movement along a 0.019 x 0.025-in stainless steel archwire, saliva-lubricated slick modules can reduce static friction at the module/archwire interface by up to 60%, regardless of the bracket system. The SPEED brackets produced the lowest friction compared with the 3 other tested bracket systems when regular modules were used. The use of slick modules, however, with all of the ligated bracket types tested significantly reduced friction to below the values recorded in the SPEED groups. Loosely tied stainless steel ligatures were found to generate the least friction.

Temporal modulation transfer functions in cochlear implantees using a method that limits overall loudness cues

PubMed Central

Fraser, Matthew; McKay, Colette M.

2012-01-01

Temporal modulation transfer functions (TMTFs) were measured for six users of cochlear implants, using different carrier rates and levels. Unlike most previous studies investigating modulation detection, the experimental design limited potential effects of overall loudness cues. Psychometric functions (percent correct discrimination of modulated from unmodulated stimuli versus modulation depth) were obtained. For each modulation depth, each modulated stimulus was loudness balanced to the unmodulated reference stimulus, and level jitter was applied in the discrimination task. The loudness-balance data showed that the modulated stimuli were louder than the unmodulated reference stimuli with the same average current, thus confirming the need to limit loudness cues when measuring modulation detection. TMTFs measured in this way had a low-pass characteristic, with a cut-off frequency (at comfortably loud levels) similar to that for normal-hearing listeners. A reduction in level caused degradation in modulation detection efficiency and a lower-cut-off frequency (i.e. poorer temporal resolution). An increase in carrier rate also led to a degradation in modulation detection efficiency, but only at lower levels or higher modulation frequencies. When detection thresholds were expressed as a proportion of dynamic range, there was no effect of carrier rate for the lowest modulation frequency (50 Hz) at either level. PMID:22146425

The Interaction between Sytactic and Semantic Modules in Chinese Learners' English Spotaneous Speech

ERIC Educational Resources Information Center

Gang, Xu

2014-01-01

According to modular theory, there are interactive effects between the central modules and language modules. The central cognition may deploy and redeploy resources from language modules. Moreover, the language modules can activate the cognitive ability. So this paper studies the spontaneous speech of students who learn English as a foreign…

Evaluation of Mismatch Losses due to Shunts in industrial Silicon Photovoltaic Modules

NASA Astrophysics Data System (ADS)

Somasundaran, P.; Shilpi, M.; Gupta, R.

2017-05-01

In order to achieve higher efficiencies in photovoltaic module technology, it is important to characterize the shunts and other defects which degrade the performance of cells and modules as well as decrease their efficiency. These shunts also affect the reliability of cells and modules. It is important to understand how much fill factor and power loss is caused by the presence of shunts in the module. Shunts not only reduce the module power output, but also affect the I-V characteristics of the cell and hence the characteristics of the shunted cells are different from those of the shunt-free cells connected in the module leading to the mismatch effect. This is an interesting effect which has been systematically investigated in the present work. Moreover, the flow of increased shunt current will give rise to increased temperature in the region of shunt, which will affect the cell and hence module performance. In the present study, the distributed diode model has been extended to the module level and applied to evaluate the electrical mismatch losses and thermal mismatch losses due to shunts in industrial Silicon PV modules.

Generation and transmission of multilevel quadrature amplitude modulation formats using only one optical modulator: MATLAB Simulink simulation models

NASA Astrophysics Data System (ADS)

Binh, Le Nguyen

2009-04-01

A geometrical and phasor representation technique is presented to illustrate the modulation of the lightwave carrier to generate quadrature amplitude modulated (QAM) signals. The modulation of the amplitude and phase of the lightwave carrier is implemented using only one dual-drive Mach-Zehnder interferometric modulator (MZIM) with the assistance of phasor techniques. Any multilevel modulation scheme can be generated, but we illustrate specifically, the multilevel amplitude and differential phase shift keying (MADPSK) signals. The driving voltage levels are estimated for driving the traveling wave electrodes of the modulator. Phasor diagrams are extensively used to demonstrate the effectiveness of modulation schemes. MATLAB Simulink models are formed to generate the multilevel modulation formats, transmission, and detection in optically amplified fiber communication systems. Transmission performance is obtained for the multilevel optical signals and proven to be equivalent or better than those of binary level with equivalent bit rate. Further, the resilience to nonlinear effects is much higher for MADPSK of 50% and 33% pulse width as compared to non-return-to-zero (NRZ) pulse shaping.

Peroxisome Proliferators-Activated Receptor (PPAR) Modulators and Metabolic Disorders

PubMed Central

Cho, Min-Chul; Lee, Kyoung; Paik, Sang-Gi; Yoon, Do-Young

2008-01-01

Overweight and obesity lead to an increased risk for metabolic disorders such as impaired glucose regulation/insulin resistance, dyslipidemia, and hypertension. Several molecular drug targets with potential to prevent or treat metabolic disorders have been revealed. Interestingly, the activation of peroxisome proliferator-activated receptor (PPAR), which belongs to the nuclear receptor superfamily, has many beneficial clinical effects. PPAR directly modulates gene expression by binding to a specific ligand. All PPAR subtypes (α, γ, and σ) are involved in glucose metabolism, lipid metabolism, and energy balance. PPAR agonists play an important role in therapeutic aspects of metabolic disorders. However, undesired effects of the existing PPAR agonists have been reported. A great deal of recent research has focused on the discovery of new PPAR modulators with more beneficial effects and more safety without producing undesired side effects. Herein, we briefly review the roles of PPAR in metabolic disorders, the effects of PPAR modulators in metabolic disorders, and the technologies with which to discover new PPAR modulators. PMID:18566691

Effectively teaching self-assessment: preparing the dental hygiene student to provide quality care.

PubMed

Jackson, Sarah C; Murff, Elizabeth J Tipton

2011-02-01

Literature on self-assessment presents substantial evidence regarding the impact of self-assessment on dental practitioners and quality of care. Related dental hygiene research documents a need to enhance self-assessment curricula; however, no published curriculum module exists to effectively teach self-assessment. The purpose of this study was to explore the impact of a self-assessment educational module for dental hygiene curricula designed using adult learning principles. This module was implemented with thirty-three dental hygiene students in their junior year using a one-group, pretest-posttest design. Results analyzed using matched pairs Wilcoxon signed-rank test indicated the self-assessment module was effective (p<0.01 corresponding to a Bonferroni FWER of 0.20) in improving some aspects of the students' perceptions and voluntary clinical application of self-assessment. No statistically significant relationship was found between the students' perceptions and their application of self-assessment using Pearson's correlation. The quality of self-assessment comments on the students' daily clinical evaluation forms was also enhanced after module implementation (p<0.05). This change in quality after module implementation was demonstrated by a quantitative analysis using a self-designed rubric and a qualitative thematic analysis of student comments to identify predominant themes. Students also were surveyed to determine which module components were most effective. Findings indicate a self-assessment educational module enhanced these dental hygiene students' self-assessment perceptions and skills.

Effects of Scene Modulation Image Blur and Noise Upon Human Target Acquisition Performance.

DTIC Science & Technology

1997-06-01

AFRL-HE-WP-TR-1998-0012 UNITED STATES AIR FORCE RESEARCH LABORATORY EFFECTS OF SCENE MODULATION IMAGE BLUR AND NOISE UPON HUMAN TARGET...COVERED INTERIM (July 1996 - August 1996) TITLE AND SUBTITLE Effects of Scene Modulation Image Blur and Noise Upon Human Target Acquisition...dilemma in image transmission and display is that we must compromise between die conflicting constraints of dynamic range and noise . Three target

The effect of small-wave modulation on the electromagnetic bias

NASA Technical Reports Server (NTRS)

Rodriguez, Ernesto; Kim, Yunjin; Martin, Jan M.

1992-01-01

The effect of the modulation of small ocean waves by large waves on the physical mechanism of the EM bias is examined by conducting a numerical scattering experiment which does not assume the applicability of geometric optics. The modulation effect of the large waves on the small waves is modeled using the principle of conservation of wave action and includes the modulation of gravity-capillary waves. The frequency dependence and magnitude of the EM bias is examined for a simplified ocean spectral model as a function of wind speed. These calculations make it possible to assess the validity of previous assumptions made in the theory of the EM bias, with respect to both scattering and hydrodynamic effects. It is found that the geometric optics approximation is inadequate for predictions of the EM bias at typical radar altimeter frequencies, while the improved scattering calculations provide a frequency dependence of the EM bias which is in qualitative agreement with observation. For typical wind speeds, the EM bias contribution due to small-wave modulation is of the same order as that due to modulation by the nonlinearities of the large-scale waves.

All-optical intensity modulation based on graphene-coated microfibre waveguides

NASA Astrophysics Data System (ADS)

Wang, Ruiduo; Li, Diao; Jiang, Man; Wu, Hao; Xu, Xiang; Ren, Zhaoyu

2018-03-01

We investigate graphene-covered microfibre (GCM) waveguides, and analyse the microfibres' evanescent field distributions in different diameters and lengths by numerically simulation. According to the simulation results, we designed a graphene-based all-optical modulator using 980 nm and Amplified Spontaneous Emission (ASE) lasers, employing the microfibre's evanescent field induced light-graphene interaction. We studied the modulation effect that is influenced by the microfibre's diameter, number of graphene layers, and effective graphene length. Compared to a single graphene layer of shorter length, the double graphene layer with longer length presents stronger absorption and higher modulation depth. Using a 2- μm diameter microfibre covered by ∼0.3 cm double graphene sheets, we achieved a modulation depth of 8.45 dB. This modulator features ease of fabrication, low cost, and a controllable modulation depth.

Spectral changes induced by a phase modulator acting as a time lens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plansinis, B. W.; Donaldson, W. R.; Agrawal, G. P.

2015-07-06

We show both numerically and experimentally that a phase modulator, acting as a time lens in the Fourier-lens configuration, can induce spectral broadening, narrowing, or shifts, depending on the phase of the modulator cycle. These spectral effects depend on the maximum phase shift that can be imposed by the modulator. In our numerical simulations, pulse spectrum could be compressed by a factor of 8 for a 30 rad phase shift. Experimentally, spectral shifts over a 1.35 nm range and spectral narrowing and broadening by a factor of 2 were demonstrated using a lithium niobate phase modulator with a maximum phasemore » shift of 16 rad at a 10 GHz modulation frequency. All spectral changes were accomplished without employing optical nonlinear effects such as self- or cross-phase modulation.« less

Advanced space system analysis software. Technical, user, and programmer guide

NASA Technical Reports Server (NTRS)

Farrell, C. E.; Zimbelman, H. F.

1981-01-01

The LASS computer program provides a tool for interactive preliminary and conceptual design of LSS. Eight program modules were developed, including four automated model geometry generators, an associated mass properties module, an appendage synthesizer module, an rf analysis module, and an orbital transfer analysis module. The existing rigid body controls analysis module was modified to permit analysis of effects of solar pressure on orbital performance. A description of each module, user instructions, and programmer information are included.

Research of Modulation of Bilateral Frequency Difference Based on Load Mode

NASA Astrophysics Data System (ADS)

Lin, Shenghong; Mao, Chizu; Zhu, Jianquan; Lu, Junyu

2017-05-01

Owning to high reliability, simple operation and easy acquirement of signals, modulation of bilateral frequency difference (MBFD) in HVDC is worthy for application in practical engineering. With the example of an AC/DC hybrid network and the software PSD-BPA, this paper analyses the effect of MBFD to DC block. The modulators parameters are setting by means of simulation. Two types of loads modes are considered to research the impact of them on simulation. The results indicate that in cooperation with operation modes adjusting at AC system, MBFD will effectively release the impact from DC block and shortage of reactive power caused by rapid variation of DC power owning to modulation. To achieve the best effect, only modulators of some HVDC systems instead of all of them are opened.

The large-scale modulation of cosmic rays in mid-1982: Its dependence on heliospheric longitude and radius

NASA Technical Reports Server (NTRS)

Pyle, K. R.; Simpson, J. A.

1985-01-01

Near solar maximum, a series of large radial solar wind shocks in June and July 1982 provided a unique opportunity to study the solar modulation of galactic cosmic rays with an array of spacecraft widely separated both in heliocentric radius and longitude. By eliminating hysteresis effects it is possible to begin to separate radial and azimuthal effects in the outer heliosphere. On the large scale, changes in modulation (both the increasing and recovery phases) propagate outward at close to the solar wind velocity, except for the near-term effects of solar wind shocks, which may propagate at a significantly higher velocity. In the outer heliosphere, azimuthal effects are small in comparison with radial effects for large-scale modulation at solar maximum.

Hepatic Hemodynamics and Portal Flow Modulation: The A2ALL Experience.

PubMed

Emond, Jean C; Goodrich, Nathan P; Pomposelli, James J; Baker, Talia B; Humar, Abhinav; Grant, David R; Abt, Peter; Friese, Chris E; Fisher, Robert A; Kam, Igal; Sherker, Averell H; Gillespie, Brenda W; Merion, Robert M

2017-10-01

A principal aim of the Adult-to-Adult Living Donor Liver Transplantation Cohort Study was to study hepatic blood flow and effect of portal flow modulation on graft outcomes in the setting of increasing use of smaller and left lobe grafts. Recipients of 274 living donor liver transplant were enrolled in the Adult-to-Adult Living Donor Liver Transplantation Cohort Study, including 233 (85.0%) right lobes, 40 (14.6%) left lobes, and 1 (0.5%) left lateral section. Hepatic hemodynamics were recorded after reperfusion. A total of 57 portal flow modulations were performed on 52 subjects. Modulation lowered portal pressure in 68% of subjects with inconsistent effects on hepatic arterial and portal flow. A higher rate of graft dysfunction was observed in modulated vs. unmodulated subjects (31% vs. 18%; P = 0.03); however, graft survival in modulated subjects was not different from unmodulated subjects at 3 years. These results suggest the need for a study using a prespecified portal flow modulation protocol with defined indications to better define the effects of these interventions.

Investigation of a GaAlAs Mach-Zehnder electro-optic modulator. M.S. Thesis. Final Contractor Report

NASA Technical Reports Server (NTRS)

Materna, David M.

1987-01-01

A GaAs modulator operating at 0.78 to 0.88 micron wavelength has the potential to be integrated with a GaAs/GaAlAs laser diode for an integrated fiber-optic transmitter. A travelling-wave Mach-Zehnder modulator using the electro-optic effect of GaAs and operating at a wavelength of 0.82 microns has been investigated for the first time. A four layer Strip-loaded ridge optical waveguide has been analyzed using the effective index method and single mode waveguides have been designed. The electro-optic effect of GaAs has also been analyzed and a modulator using the geometry producing the maximum phase shift has been designed. A coplanar transmission line structure is used in an effort to tap the potentially higher bandwidth of travelling-wave electrodes. The modulator bandwidth has been calculated at 11.95 GHz with a required drive power of 2.335 Watts for full intensity modulation. Finally, some preliminary experiments were performed to characterize a fabrication process for the modulator.

Grape seed procyanidin extract modulates proliferation and apoptosis of pancreatic beta-cells.

PubMed

Cedó, Lídia; Castell-Auví, Anna; Pallarès, Victor; Blay, Mayte; Ardévol, Anna; Arola, Lluís; Pinent, Montserrat

2013-05-01

Grape seed procyanidin extract (GSPE) modulates glucose homeostasis and insulinemia in several animal models. Under pathological conditions, insulin levels are dependent on pancreatic beta-cell functionality, as well as on the beta-cell mass expansion or apoptosis in the pancreas. In this study, we analysed the effects of GSPE on modulating apoptosis and proliferation in beta-cells. We tested the effects of GSPE in the INS-1E pancreatic beta-cell line, either under basal or altered conditions with high glucose, insulin or palmitate levels. GSPE enhanced the pro-apoptotic effect of high glucose and showed clear antiproliferative effects under high glucose, insulin and palmitate conditions. These antiproliferative effects are likely due to high molecular weight compounds contained in the extract. GSPE also modulated pro- and anti-apoptotic markers in the pancreas of rats fed a cafeteria diet, with the effect depending on the dose of GSPE and duration of treatment. Thus, GSPE is able to modulate apoptosis and proliferation of beta-cells under altered, but not basal, conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Modulation-doped β-(Al0.2Ga0.8)2O3/Ga2O3 field-effect transistor

NASA Astrophysics Data System (ADS)

Krishnamoorthy, Sriram; Xia, Zhanbo; Joishi, Chandan; Zhang, Yuewei; McGlone, Joe; Johnson, Jared; Brenner, Mark; Arehart, Aaron R.; Hwang, Jinwoo; Lodha, Saurabh; Rajan, Siddharth

2017-07-01

Modulation-doped heterostructures are a key enabler for realizing high mobility and better scaling properties for high performance transistors. We report the realization of a modulation-doped two-dimensional electron gas (2DEG) at the β-(Al0.2Ga0.8)2O3/Ga2O3 heterojunction by silicon delta doping. The formation of a 2DEG was confirmed using capacitance voltage measurements. A modulation-doped 2DEG channel was used to realize a modulation-doped field-effect transistor. The demonstration of modulation doping in the β-(Al0.2Ga0.8)2O3/Ga2O3 material system could enable heterojunction devices for high performance electronics.

Equity and Urban Service Distribution, Package XVIII. Module 1; Module 2: Handbook for Analyzing the Distribution of Solid Waste Collection Services; Module 3: Handbook for Analyzing the Distribution of Library Services; Module 4: Handbook for Analyzing the Distribution of Park Services; Module 5: Handbook for Analyzing the Distribution of Police Services.

ERIC Educational Resources Information Center

Lucy, William H.; Mladenka, Kenneth R.

This package contains the student materials for five modules which comprise a portion of the National Training and Development Service Urban Management Curriculum Development Project. These modules focus on the distribution of services in urban areas. Module One presents chapters on service distribution and equity, effectiveness, decision making,…

Colour changes of orthodontic elastomeric module materials exposed to in vitro dietary media.

PubMed

Ardeshna, Anil P; Vaidyanathan, Tritala K

2009-09-01

To evaluate the colour stability of orthodontic elastomeric module material exposed to dietary media. An in vitro laboratory study. Coloured and clear orthodontic elastomeric modules from four companies were exposed to coffee, cola, tea and spices for 72 h. The difference in colour components was measured with a Minolta chromameter before and after exposure. Significant changes in colour, including grey level and chromaticity, both as a function of colour and company of elastomeric ligature module were found following exposure to beverages and spices. Colour change was most affected by Deltab* (yellowness) and most significant in clear modules. Modules made using injection mouldings were more resistant to colour change than those by extrusion. Spice mix had the most effect and cola beverage the least. Clinically, these changes compromised both colour stability and esthetics of the elastomeric module. Clinicians should make patients aware of the effect of consuming beverages and spices on the colour stability of their selected ligature modules. Clinicians should favour modules made with injection moulding. Darker colour modules may be preferred to clear modules to avoid excessive colour degradation through dietary media such as beverages and food spices. Patients consuming large amounts of spices or coffee should avoid clear modules made by extrusion processing because of their tendency to discolour.

Large current modulation and tunneling magnetoresistance change by a side-gate electric field in a GaMnAs-based vertical spin metal-oxide-semiconductor field-effect transistor.

PubMed

Kanaki, Toshiki; Yamasaki, Hiroki; Koyama, Tomohiro; Chiba, Daichi; Ohya, Shinobu; Tanaka, Masaaki

2018-05-08

A vertical spin metal-oxide-semiconductor field-effect transistor (spin MOSFET) is a promising low-power device for the post scaling era. Here, using a ferromagnetic-semiconductor GaMnAs-based vertical spin MOSFET with a GaAs channel layer, we demonstrate a large drain-source current I DS modulation by a gate-source voltage V GS with a modulation ratio up to 130%, which is the largest value that has ever been reported for vertical spin field-effect transistors thus far. We find that the electric field effect on indirect tunneling via defect states in the GaAs channel layer is responsible for the large I DS modulation. This device shows a tunneling magnetoresistance (TMR) ratio up to ~7%, which is larger than that of the planar-type spin MOSFETs, indicating that I DS can be controlled by the magnetization configuration. Furthermore, we find that the TMR ratio can be modulated by V GS . This result mainly originates from the electric field modulation of the magnetic anisotropy of the GaMnAs ferromagnetic electrodes as well as the potential modulation of the nonmagnetic semiconductor GaAs channel layer. Our findings provide important progress towards high-performance vertical spin MOSFETs.

Sniffer patch laser uncaging response (SPLURgE): an assay of regional differences in allosteric receptor modulation and neurotransmitter clearance

PubMed Central

Christian, Catherine A.

2013-01-01

Allosteric modulators exert actions on neurotransmitter receptors by positively or negatively altering the effective response of these receptors to their respective neurotransmitter. γ-Aminobutyric acid (GABA) type A ionotropic receptors (GABAARs) are major targets for allosteric modulators such as benzodiazepines, neurosteroids, and barbiturates. Analysis of substances that produce similar effects has been hampered by the lack of techniques to assess the localization and function of such agents in brain slices. Here we describe measurement of the sniffer patch laser uncaging response (SPLURgE), which combines the sniffer patch recording configuration with laser photolysis of caged GABA. This methodology enables the detection of allosteric GABAAR modulators endogenously present in discrete areas of the brain slice and allows for the application of exogenous GABA with spatiotemporal control without altering the release and localization of endogenous modulators within the slice. Here we demonstrate the development and use of this technique for the measurement of allosteric modulation in different areas of the thalamus. Application of this technique will be useful in determining whether a lack of modulatory effect on a particular category of neurons or receptors is due to insensitivity to allosteric modulation or a lack of local release of endogenous ligand. We also demonstrate that this technique can be used to investigate GABA diffusion and uptake. This method thus provides a biosensor assay for rapid detection of endogenous GABAAR modulators and has the potential to aid studies of allosteric modulators that exert effects on other classes of neurotransmitter receptors, such as glutamate, acetylcholine, or glycine receptors. PMID:23843428

Sniffer patch laser uncaging response (SPLURgE): an assay of regional differences in allosteric receptor modulation and neurotransmitter clearance.

PubMed

Christian, Catherine A; Huguenard, John R

2013-10-01

Allosteric modulators exert actions on neurotransmitter receptors by positively or negatively altering the effective response of these receptors to their respective neurotransmitter. γ-Aminobutyric acid (GABA) type A ionotropic receptors (GABAARs) are major targets for allosteric modulators such as benzodiazepines, neurosteroids, and barbiturates. Analysis of substances that produce similar effects has been hampered by the lack of techniques to assess the localization and function of such agents in brain slices. Here we describe measurement of the sniffer patch laser uncaging response (SPLURgE), which combines the sniffer patch recording configuration with laser photolysis of caged GABA. This methodology enables the detection of allosteric GABAAR modulators endogenously present in discrete areas of the brain slice and allows for the application of exogenous GABA with spatiotemporal control without altering the release and localization of endogenous modulators within the slice. Here we demonstrate the development and use of this technique for the measurement of allosteric modulation in different areas of the thalamus. Application of this technique will be useful in determining whether a lack of modulatory effect on a particular category of neurons or receptors is due to insensitivity to allosteric modulation or a lack of local release of endogenous ligand. We also demonstrate that this technique can be used to investigate GABA diffusion and uptake. This method thus provides a biosensor assay for rapid detection of endogenous GABAAR modulators and has the potential to aid studies of allosteric modulators that exert effects on other classes of neurotransmitter receptors, such as glutamate, acetylcholine, or glycine receptors.

Dynamic carrier transport modulation for constructing advanced devices with improved performance by piezotronic and piezo-phototronic effects: a brief review

NASA Astrophysics Data System (ADS)

Guo, Zhen; Pan, Haixi; Li, Chuanyu; Zhang, Lili; Yan, Shuai; Zhang, Wei; Yao, Jia; Tang, Yuguo; Yang, Hongbo; Wu, Yihui; Feng, Liping; Zhou, Lianqun

2017-08-01

Carrier generation, transport, separation, and recombination behaviors can be modulated for improving the performance of semiconductor devices by using piezotronic and piezo-phototronic effects with creating piezopotential in crystals based on non-centrosymmetric semiconductor materials such as group II-VI and III-V semiconductors and transition metal dichalcogenides (TMDCs), which have emerged as attractive materials for electronic/photonic applications because of their novel properties. Until now, much effort has been devoted to improving the performance of devices based on the aforementioned materials through modulation of the carrier behavior. However, due to existing drawbacks, it has been difficult to further enhance the device performance for a built structure. However, effective exploration of the piezotronic and piezo-phototronic effects in these semiconducting materials could pave the way to the realization of high-performance devices. In general, the effective modulation of carrier behavior dynamically in devices such as light-emitting diodes, photodetectors, solar cells, nanogenerators, and so on, remains a key challenge. Due to the polarization of ions in semiconductor materials with noncentral symmetry under external strain, a piezopotential is created considering piezotronic and piezo-photoronic effects, which could dynamically modulate charge carrier transport behaviors across p-n junctions or metal-semiconductor interfaces. Through a combination of these effects and semiconductor properties, the performance of the related devices could be improved and new types of devices such as piezoelectric field-effect transistors and sensors have emerged, with potential applications in self-driven devices for effective energy harvesting and biosensing with high sensitivity, which are different from those traditionally designed and may have potential applications in strained triggered devices. The objective of this review is to briefly introduce the corresponding mechanisms for modulating carrier behavior on the basis of piezotronic and piezo-phototronic effects in materials such as group II-VI and group III-V semiconductors and TMDCs, as well as to discuss possible solutions to effectively enhance the performance of the devices via carrier modulation.

Auditory sensitivity to spectral modulation phase reversal as a function of modulation depth

PubMed Central

Grose, John

2018-01-01

The present study evaluated auditory sensitivity to spectral modulation by determining the modulation depth required to detect modulation phase reversal. This approach may be preferable to spectral modulation detection with a spectrally flat standard, since listeners appear unable to perform the task based on the detection of temporal modulation. While phase reversal thresholds are often evaluated by holding modulation depth constant and adjusting modulation rate, holding rate constant and adjusting modulation depth supports rate-specific assessment of modulation processing. Stimuli were pink noise samples, filtered into seven octave-wide bands (0.125–8 kHz) and spectrally modulated in dB. Experiment 1 measured performance as a function of modulation depth to determine appropriate units for adaptive threshold estimation. Experiment 2 compared thresholds in dB for modulation detection with a flat standard and modulation phase reversal; results supported the idea that temporal cues were available at high rates for the former but not the latter. Experiment 3 evaluated spectral modulation phase reversal thresholds for modulation that was restricted to either one or two neighboring bands. Flanking bands of unmodulated noise had a larger detrimental effect on one-band than two-band targets. Thresholds for high-rate modulation improved with increasing carrier frequency up to 2 kHz, whereas low-rate modulation appeared more consistent across frequency, particularly in the two-band condition. Experiment 4 measured spectral weights for spectral modulation phase reversal detection and found higher weights for bands in the spectral center of the stimulus than for the lowest (0.125 kHz) or highest (8 kHz) band. Experiment 5 compared performance for highly practiced and relatively naïve listeners, and found weak evidence of a larger practice effect at high than low spectral modulation rates. These results provide preliminary data for a task that may provide a better estimate of sensitivity to spectral modulation than spectral modulation detection with a flat standard. PMID:29621338

Interdisciplinary Integration of the CVS Module and Its Effect on Faculty and Student Satisfaction as Well as Student Performance

PubMed Central

2012-01-01

Background Beyond the adoption of the principles of horizontal and vertical integration, significant planning and implementation of curriculum reform is needed. This study aimed to assess the effect of the interdisciplinary integrated Cardiovascular System (CVS) module on both student satisfaction and performance and comparing them to those of the temporally coordinated CVS module that was implemented in the previous year at the faculty of Medicine of the King Abdulaziz University, Saudi Arabia. Methods This interventional study used mixed method research design to assess student and faculty satisfaction with the level of integration within the CVS module. A team from the medical education department was assembled in 2010/2011 to design a plan to improve the CVS module integration level. After delivering the developed module, both student and faculty satisfaction as well as students performance were assessed and compared to those of the previous year to provide an idea about module effectiveness. Results Many challenges faced the medical education team during design and implementation of the developed CVS module e.g. resistance of faculty members to change, increasing the percentage of students directed learning hours from the total contact hour allotted to the module and shifting to integrated item writing in students assessment, spite of that the module achieved a significant increase in both teaching faculty and student satisfaction as well as in the module scores. Conclusion The fully integrated CVS has yielded encouraging results that individual teachers or other medical schools who attempt to reformulate their curriculum may find valuable. PMID:22747781

The utility of adaptive eLearning in cervical cytopathology education.

PubMed

Samulski, T Danielle; Taylor, Laura A; La, Teresa; Mehr, Chelsea R; McGrath, Cindy M; Wu, Roseann I

2018-02-01

Adaptive eLearning allows students to experience a self-paced, individualized curriculum based on prior knowledge and learning ability. The authors investigated the effectiveness of adaptive online modules in teaching cervical cytopathology. eLearning modules were created that covered basic concepts in cervical cytopathology, including artifacts and infections, squamous lesions (SL), and glandular lesions (GL). The modules used student responses to individualize the educational curriculum and provide real-time feedback. Pathology trainees and faculty from the authors' institution were randomized into 2 groups (SL or GL), and identical pre-tests and post-tests were used to compare the efficacy of eLearning modules versus traditional study methods (textbooks and slide sets). User experience was assessed with a Likert scale and free-text responses. Sixteen of 17 participants completed the SL module, and 19 of 19 completed the GL module. Participants in both groups had improved post-test scores for content in the adaptive eLearning module. Users indicated that the module was effective in presenting content and concepts (Likert scale [from 1 to 5], 4.3 of 5.0), was an efficient and convenient way to review the material (Likert scale, 4.4 of 5.0), and was more engaging than lectures and texts (Likert scale, 4.6 of 5.0). Users favored the immediate feedback and interactivity of the module. Limitations included the inability to review prior content and slow upload time for images. Learners demonstrated improvement in their knowledge after the use of adaptive eLearning modules compared with traditional methods. Overall, the modules were viewed positively by participants. Adaptive eLearning modules can provide an engaging and effective adjunct to traditional teaching methods in cervical cytopathology. Cancer Cytopathol 2018;126:129-35. © 2017 American Cancer Society. © 2017 American Cancer Society.

The Effect of Dynamic Pitch on Speech Recognition in Temporally Modulated Noise

ERIC Educational Resources Information Center

Shen, Jung; Souza, Pamela E.

2017-01-01

Purpose: This study investigated the effect of dynamic pitch in target speech on older and younger listeners' speech recognition in temporally modulated noise. First, we examined whether the benefit from dynamic-pitch cues depends on the temporal modulation of noise. Second, we tested whether older listeners can benefit from dynamic-pitch cues for…

Trial-to-Trial Modulations of the Simon Effect in Conditions of Attentional Limitations : Evidence from Dual Tasks

ERIC Educational Resources Information Center

Fischer, Rico; Plessow, Franziska; Kunde, Wilfried; Kiesel, Andrea

2010-01-01

Interference effects are reduced after trials including response conflict. This sequential modulation has often been attributed to a top-down mediated adaptive control mechanism and/or to feature repetition mechanisms. In the present study we tested whether mechanisms responsible for such sequential modulations are subject to attentional…

Reduction of conditioned pain modulation in humans by naltrexone: an exploratory study of the effects of pain catastrophizing

PubMed Central

Goodin, Burel; Kindler, Lindsay L.; Caudle, Robert M.; Edwards, Robert R.; Gravenstein, Nikolaus; Riley, Joseph L.; Fillingim, Roger B.

2013-01-01

The current study tested the hypothesis that conditioned pain modulation is mediated by the release of endogenous opioids with a placebo-controlled (sugar pill) study of naltrexone (50 mg) in 33 healthy volunteers over two counter-balanced sessions. Pain modulation consisted of rating of heat pain (palm) during concurrent cold water immersion (foot). Compared to baseline heat pain ratings, concurrent foot immersion lowered pain intensity ratings, which suggests an inhibitory effect, was reduced with naltrexone, suggesting at least partial dependence of inhibition on endogenous opioids. An exploratory analysis revealed that individual differences in catastrophizing moderated the effects of naltrexone; endogenous opioid blockade abolished modulation in subjects lower in catastrophizing while modulation was unaffected by naltrexone among high catastrophizers. The results suggest a role of endogenous opioids in endogenous analgesia, but hint that multiple systems might contribute to conditioned pain modulation, and that these systems might be differentially activated as a function of individual differences in responses to pain. PMID:22534819

Ketamine induces a robust whole-brain connectivity pattern that can be differentially modulated by drugs of different mechanism and clinical profile.

PubMed

Joules, R; Doyle, O M; Schwarz, A J; O'Daly, O G; Brammer, M; Williams, S C; Mehta, M A

2015-11-01

Ketamine, an N-methyl-D-aspartate receptor (NMDAR) antagonist, has been studied in relation to the glutamate hypothesis of schizophrenia and increases dissociation, positive and negative symptom ratings. Ketamine effects brain function through changes in brain activity; these activity patterns can be modulated by pre-treatment of compounds known to attenuate the effects of ketamine on glutamate release. Ketamine also has marked effects on brain connectivity; we predicted that these changes would also be modulated by compounds known to attenuate glutamate release. Here, we perform task-free pharmacological magnetic resonance imaging (phMRI) to investigate the functional connectivity effects of ketamine in the brain and the potential modulation of these effects by pre-treatment of the compounds lamotrigine and risperidone, compounds hypothesised to differentially modulate glutamate release. Connectivity patterns were assessed by combining windowing, graph theory and multivariate Gaussian process classification. We demonstrate that ketamine has a robust effect on the functional connectivity of the human brain compared to saline (87.5 % accuracy). Ketamine produced a shift from a cortically centred, to a subcortically centred pattern of connections. This effect is strongly modulated by pre-treatment with risperidone (81.25 %) but not lamotrigine (43.75 %). Based on the differential effect of these compounds on ketamine response, we suggest the observed connectivity effects are primarily due to NMDAR blockade rather than downstream glutamatergic effects. The connectivity changes contrast with amplitude of response for which no differential effect between pre-treatments was detected, highlighting the necessity of these techniques in forming an informed view of the mechanistic effects of pharmacological compounds in the human brain.

The Implications of Encoder/Modulator/ Phased Array Designs for Future Broadband LEO Communications

NASA Technical Reports Server (NTRS)

Vanderaar, Mark; Jensen, Chris A.; Terry, John D.

1997-01-01

In this paper we summarize the effects of modulation and channel coding on the design of wide angle scan, broadband, phased army antennas. In the paper we perform several trade studies. First, we investigate the amplifier back-off requirement as a function of variability of modulation envelope. Specifically, we contrast constant and non-constant envelope modulations, as well as single and multiple carrier schemes. Additionally, we address the issues an(f concerns of using pulse shaping filters with the above modulation types. Second, we quantify the effects of beam steering on the quality of data, recovery using selected modulation techniques. In particular, we show that the frequency response of the array introduces intersymbol interference for broadband signals and that the mode of operation for the beam steering controller may introduce additional burst or random errors. Finally, we show that the encoder/modulator design must be performed in conjunction with the phased array antenna design.

Thermal imaging of spin Peltier effect

NASA Astrophysics Data System (ADS)

Daimon, Shunsuke; Iguchi, Ryo; Hioki, Tomosato; Saitoh, Eiji; Uchida, Ken-Ichi

2016-12-01

The Peltier effect modulates the temperature of a junction comprising two different conductors in response to charge currents across the junction, which is used in solid-state heat pumps and temperature controllers in electronics. Recently, in spintronics, a spin counterpart of the Peltier effect was observed. The `spin Peltier effect' modulates the temperature of a magnetic junction in response to spin currents. Here we report thermal imaging of the spin Peltier effect; using active thermography technique, we visualize the temperature modulation induced by spin currents injected into a magnetic insulator from an adjacent metal. The thermal images reveal characteristic distribution of spin-current-induced heat sources, resulting in the temperature change confined only in the vicinity of the metal/insulator interface. This finding allows us to estimate the actual magnitude of the temperature modulation induced by the spin Peltier effect, which is more than one order of magnitude greater than previously believed.

Side-gate modulation effects on high-quality BN-Graphene-BN nanoribbon capacitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yang; Chen, Xiaolong; Ye, Weiguang

High-quality BN-Graphene-BN nanoribbon capacitors with double side-gates of graphene have been experimentally realized. The double side-gates can effectively modulate the electronic properties of graphene nanoribbon capacitors. By applying anti-symmetric side-gate voltages, we observed significant upward shifting and flattening of the V-shaped capacitance curve near the charge neutrality point. Symmetric side-gate voltages, however, only resulted in tilted upward shifting along the opposite direction of applied gate voltages. These modulation effects followed the behavior of graphene nanoribbons predicted theoretically for metallic side-gate modulation. The negative quantum capacitance phenomenon predicted by numerical simulations for graphene nanoribbons modulated by graphene side-gates was not observed,more » possibly due to the weakened interactions between the graphene nanoribbon and side-gate electrodes caused by the Ga{sup +} beam etching process.« less

Monitoring the Recovery of c-Si Modules from Potential-Induced Degradation Using Suns-Voc Curves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilterdink, Harrison; Sinton, Ronald; Hacke, Peter

2016-11-21

Potential-induced degradation (PID) has recently been shown as an important failure mode in c-Si modules. We demonstrate the utility of Suns-Voc analysis for measuring shunt effects caused by PID at the module level. Our results show module shunt resistance increasing in step with module power during recovery from the degraded state.

Performance losses in rooftop-mounted PV modules from long-term environmental exposure at Las Cruces, New Mexico

NASA Astrophysics Data System (ADS)

Rosenthal, Andrew L.; Czanderna, A. W.; Pern, F. J.

1999-03-01

Forty-eight PV modules of four different types were instrumented and tested monthly for 3 years to measure and record the performance effects of environmental exposure. Two modules were removed from each set of 12 as a control and for "initial" characterization. As a secondary goal, the effects of mounting topology (open rack, integrated roof, conventional standoff mount) were also closely monitored. Current-voltage (I-V) curve data were archived and normalized according to accepted methods. The EVA pottant in all modules monitored was discolored to a deep yellow-to-brown color from prior exposures before the monitoring was begun. Modules showing observable performance degradation were removed from their mounts and prepared for in-depth analysis. During the 3-year monitoring period, 4 of the 10 Solarex a-Si modules stopped producing, 3 of the 10 Solarex MIT pc-Si modules lost from 5% to 10% efficiency, and 1 Mobil Ra-180 pc-Si module lost about 10% efficiency. For all of the other modules, a loss of less than 1% per year was recorded, which included all 10 of the Sovonics P-101 a-Si modules.

The effect of interference on delta modulation encoded video signals

NASA Technical Reports Server (NTRS)

Schilling, D. L.

1979-01-01

The results of a study on the use of the delta modulator as a digital encoder of television signals are presented. The computer simulation was studied of different delta modulators in order to find a satisfactory delta modulator. After finding a suitable delta modulator algorithm via computer simulation, the results are analyzed and then implemented in hardware to study the ability to encode real time motion pictures from an NTSC format television camera. The effects were investigated of channel errors on the delta modulated video signal and several error correction algorithms were tested via computer simulation. A very high speed delta modulator was built (out of ECL logic), incorporating the most promising of the correction schemes, so that it could be tested on real time motion pictures. The final area of investigation concerned itself with finding delta modulators which could achieve significant bandwidth reduction without regard to complexity or speed. The first such scheme to be investigated was a real time frame to frame encoding scheme which required the assembly of fourteen, 131,000 bit long shift registers as well as a high speed delta modulator. The other schemes involved two dimensional delta modulator algorithms.

Interference Resilient Sigma Delta-Based Pulse Oximeter.

PubMed

Shokouhian, Mohsen; Morling, Richard; Kale, Izzet

2016-06-01

Ambient light and optical interference can severely affect the performance of pulse oximeters. The deployment of a robust modulation technique to drive the pulse oximeter LEDs can reduce these unwanted effects and increases the resilient of the pulse oximeter against artificial ambient light. The time division modulation technique used in conventional pulse oximeters can not remove the effect of modulated light coming from surrounding environment and this may cause huge measurement error in pulse oximeter readings. This paper presents a novel cross-coupled sigma delta modulator which ensures that measurement accuracy will be more robust in comparison with conventional fixed-frequency oximeter modulation technique especially in the presence of pulsed artificial ambient light. Moreover, this novel modulator gives an extra control over the pulse oximeter power consumption leading to improved power management.

Predictors of adherence among community users of a cognitive behavior therapy website

PubMed Central

Batterham, Philip J; Neil, Alison L; Bennett, Kylie; Griffiths, Kathleen M; Christensen, Helen

2008-01-01

Objective To investigate the predictors of early and late dropout among community users of the MoodGYM website, a five module online intervention for reducing the symptoms of depression. Method Approximately 82,000 users accessed the site in 2006, of which 27% completed one module and 10% completed two or more modules. Adherence was modeled as a trichotomous variable representing non-starters (0 modules), early dropouts (1 module) and late dropouts (2–5 modules). Predictor variables included age, gender, education, location, referral source, depression severity, anxiety severity, dysfunctional thinking, and change in symptom count. Results Better adherence was predicted by higher depression severity, higher anxiety severity, a greater level of dysfunctional thinking, younger age, higher education, being female, and being referred to the site by a mental health professional. In addition, users whose depression severity had improved or remained stable after the first intervention module had higher odds of completing subsequent modules. Conclusions While the effect of age and the null effect of location were in accordance with prior adherence research, the significant effects of gender, education and depression severity were not, and may reflect user characteristics, the content of the intervention and unique aspects of online interventions. Further research directions are suggested to investigate the elements of open access online interventions that facilitate adherence. PMID:19920949

Interactions between amplitude modulation and frequency modulation processing: Effects of age and hearing loss.

PubMed

Paraouty, Nihaad; Ewert, Stephan D; Wallaert, Nicolas; Lorenzi, Christian

2016-07-01

Frequency modulation (FM) and amplitude modulation (AM) detection thresholds were measured for a 500-Hz carrier frequency and a 5-Hz modulation rate. For AM detection, FM at the same rate as the AM was superimposed with varying FM depth. For FM detection, AM at the same rate was superimposed with varying AM depth. The target stimuli always contained both amplitude and frequency modulations, while the standard stimuli only contained the interfering modulation. Young and older normal-hearing listeners, as well as older listeners with mild-to-moderate sensorineural hearing loss were tested. For all groups, AM and FM detection thresholds were degraded in the presence of the interfering modulation. AM detection with and without interfering FM was hardly affected by either age or hearing loss. While aging had an overall detrimental effect on FM detection with and without interfering AM, there was a trend that hearing loss further impaired FM detection in the presence of AM. Several models using optimal combination of temporal-envelope cues at the outputs of off-frequency filters were tested. The interfering effects could only be predicted for hearing-impaired listeners. This indirectly supports the idea that, in addition to envelope cues resulting from FM-to-AM conversion, normal-hearing listeners use temporal fine-structure cues for FM detection.

32 CFR 179.6 - Procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Chemical Warfare Materiel Hazard Evaluation (CHE) module. (1) The CHE module provides an evaluation of the chemical hazards associated with the physiological effects of CWM. The CHE module is used only when CWM are... used for evaluating the potential hazards posed by MC and other chemical contaminants. The HHE module...

76 FR 78313 - Crystalline Silicon Photovoltaic Cells and Modules From China

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-16

...)] Crystalline Silicon Photovoltaic Cells and Modules From China Determinations On the basis of the record \\1... injured by reason of imports from China of crystalline silicon photovoltaic cells and modules, provided... imports of crystalline silicon photovoltaic cells and modules from China. Accordingly, effective October...

Electro-Optic Effect in the PESO Acousto-Optic Modulator

DTIC Science & Technology

1994-11-09

AD-A286 355 NAIC-ID(RS)T-0395-94 NATIONAL AIR INTELLIGENCE CENTER ELECTRO - OPTIC EFFECT IN THE PESO ACOUSTO-OPTIC MODULATOR by Tai Renzhong, Lu Futun...owing to coupling.betw;ee.elecuc grazing" and "acou- tic grating". Linear electro - optic effect in PESO modulator is helpful to the diffraction and...crystaO A-l/Am,ARjAb, anl / ar:.. thtta=30 and theta=900 . Along these two orientations. th;- electro - optic effect is restricted tcŽ the rn :-t m:,n e

Effect of the incidence angle to free space optical communication based on cat-eye modulating retro-reflector

NASA Astrophysics Data System (ADS)

Zhang, Lai-xian; Sun, Hua-yan; Zhao, Yan-zhong; Zheng, Yong-hui; Shan, Cong-miao

2013-08-01

Based on the cat-eye effect of optical system, free space optical communication based on cat-eye modulating retro-reflector can build communication link rapidly. Compared to classical free space optical communication system, system based on cat-eye modulating retro-reflector has great advantages such as building communication link more rapidly, a passive terminal is smaller, lighter and lower power consuming. The incident angle is an important factor of cat-eye effect, so it will affect the retro-reflecting communication link. In this paper, the principle and work flow of free space optical communication based on cat-eye modulating retro-reflector were introduced. Then, using the theory of geometric optics, the equivalent model of modulating retro-reflector with incidence angle was presented. The analytical solution of active area and retro-reflected light intensity of cat-eye modulating retro-reflector were given. Noise of PIN photodetector was analyzed, based on which, bit error rate of free space optical communication based on cat-eye modulating retro-reflector was presented. Finally, simulations were done to study the effect of incidence angle to the communication. The simulation results show that the incidence angle has little effect on active area and retro-reflected light intensity when the incidence beam is in the active field angle of cat-eye modulating retro-reflector. With certain system and condition, the communication link can rapidly be built when the incidence light beam is in the field angle, and the bit error rate increases greatly with link range. When link range is smaller than 35Km, the bit error rate is less than 10-16.

Frequency characteristics of standing-wave acoustooptic modulators

NASA Astrophysics Data System (ADS)

Apolonskii, A. A.; Shchebetov, S. D.

1991-10-01

Experimental data are presented on the performance of wide-aperture standing-wave acoustooptic modulators used as laser mode lockers. In particular, attention is given to the acoustooptic and electrical frequency characteristics of the modulators. The existence of a large effective diffraction frequency region below the fundamental frequency is demonstrated. Individual frequency regions of effective diffraction do not correspond to the even and odd harmonics.

Selective Influence of Circadian Modulation and Task Characteristics on Motor Imagery Time

ERIC Educational Resources Information Center

Debarnot, Ursula; Sahraoui, Djafar; Champely, Stephane; Collet, Christian; Guillot, Aymeric

2012-01-01

In this study, we examined the effect of circadian modulation on motor imagery (MI) time while also considering the effects of task complexity and duration. The ability to imagine in real time was influenced by circadian modulation in a simple walking condition, with longer MI times in the morning and evening sessions. By contrast, there was no…

The Effectiveness of a Virtual Field Trip (VFT) Module in Learning Biology

ERIC Educational Resources Information Center

Haris, Norbaizura; Osman, Kamisah

2015-01-01

Virtual Field Trip is a computer aided module of science developed to study the Colonisation and Succession in Mangrove Swamps, as an alternative to the real field trip in Form for Biology. This study is to identify the effectiveness of the Virtual Field Trip (VFT) module towards the level of achievement in the formative test for this topic. This…

The effectiveness of web-programming module based on scientific approach to train logical thinking ability for students in vocational high school

NASA Astrophysics Data System (ADS)

Nashiroh, Putri Khoirin; Kamdi, Waras; Elmunsyah, Hakkun

2017-09-01

Web programming is a basic subject in Computer and Informatics Engineering, a program study in a vocational high school. It requires logical thinking ability in its learning activities. The purposes of this research were (1) to develop a web programming module that implement scientific approach that can improve logical thinking ability for students in vocational high school; and (2) to test the effectiveness of web programming module based on scientific approach to train students' logical thinking ability. The results of this research was a web-programming module that apply scientific approach for learning activities to improve logical thinking ability of students in the vocational high school. The results of the effectiveness test of web-programming module give conclusion that it was very effective to train logical thinking ability and to improve learning result, this conclusion was supported by: (1) the average of posttest result of students exceeds the minimum criterion value, it was 79.91; (2) the average percentage of students' logical thinking score is 82,98; and (3) the average percentage of students' responses to the web programming module was 81.86%.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Atmaram, G.H.; Ventre, G.G.; Maytrott, C.W.

This study evaluates the long-term effects of outdoor exposure and high voltage operation on the performance and reliability of flat-plate crystalline silicon photovoltaic modules. The photovoltaic modules selected for this study were employed in the arrays of grid-connected residential photovoltaic prototype systems for over ten years at the Southeast Regional Experiment Station (SE RES) in Cape Canaveral, Florida. The modules included Mobil Ra-180 EFG ribbon silicon modules, Photowatt MU-7061 and ARCO 16-2000 single-crystal silicon modules with round cells. The Mobil and Photowatt modules were Block 5 generation, while the ARCO modules were Block 4 generation type. In all three typesmore » of photovoltaic modules (Mobil, Photowatt and ARCO), no significant power loss occurred over more than ten years of outdoor operation in the warm, humid and ocean-salt environments of coastal Florida. However, the wet insulation resistance values of a majority of the modules in all three types were lower than the values recommended in IEEE Standard 1262. This indicates potential future safety, reliability and lifetime related problems. The visual defects were more pronounced in the ARCO modules, which were manufactured in 1980 than in the Mobil and Photowatt modules, both of which were fabricated in 1983. The ARCO modules showed significant damage to the back surface tedlar in the form of tearing of the tedlar. All of the Mobil and most of the ARCO modules showed significant browning of the encapsulant, while only about half of the Photowatt modules showed significant encapsulant browning. The encapsulant discoloration generally did not appear to have any effect on the modules` power generation.« less

33 CFR 149.641 - What are the structural fire protection requirements for accommodation spaces and modules?

Code of Federal Regulations, 2011 CFR

2011-07-01

... protection requirements for accommodation spaces and modules? 149.641 Section 149.641 Navigation and... the structural fire protection requirements for accommodation spaces and modules? (a) Accommodation spaces and modules must be designed, located, and constructed so as to minimize the effects of flame...

POEM: Identifying Joint Additive Effects on Regulatory Circuits.

PubMed

Botzman, Maya; Nachshon, Aharon; Brodt, Avital; Gat-Viks, Irit

2016-01-01

Expression Quantitative Trait Locus (eQTL) mapping tackles the problem of identifying variation in DNA sequence that have an effect on the transcriptional regulatory network. Major computational efforts are aimed at characterizing the joint effects of several eQTLs acting in concert to govern the expression of the same genes. Yet, progress toward a comprehensive prediction of such joint effects is limited. For example, existing eQTL methods commonly discover interacting loci affecting the expression levels of a module of co-regulated genes. Such "modularization" approaches, however, are focused on epistatic relations and thus have limited utility for the case of additive (non-epistatic) effects. Here we present POEM (Pairwise effect On Expression Modules), a methodology for identifying pairwise eQTL effects on gene modules. POEM is specifically designed to achieve high performance in the case of additive joint effects. We applied POEM to transcription profiles measured in bone marrow-derived dendritic cells across a population of genotyped mice. Our study reveals widespread additive, trans-acting pairwise effects on gene modules, characterizes their organizational principles, and highlights high-order interconnections between modules within the immune signaling network. These analyses elucidate the central role of additive pairwise effect in regulatory circuits, and provide computational tools for future investigations into the interplay between eQTLs. The software described in this article is available at csgi.tau.ac.il/POEM/.

POEM: Identifying Joint Additive Effects on Regulatory Circuits

PubMed Central

Botzman, Maya; Nachshon, Aharon; Brodt, Avital; Gat-Viks, Irit

2016-01-01

Motivation: Expression Quantitative Trait Locus (eQTL) mapping tackles the problem of identifying variation in DNA sequence that have an effect on the transcriptional regulatory network. Major computational efforts are aimed at characterizing the joint effects of several eQTLs acting in concert to govern the expression of the same genes. Yet, progress toward a comprehensive prediction of such joint effects is limited. For example, existing eQTL methods commonly discover interacting loci affecting the expression levels of a module of co-regulated genes. Such “modularization” approaches, however, are focused on epistatic relations and thus have limited utility for the case of additive (non-epistatic) effects. Results: Here we present POEM (Pairwise effect On Expression Modules), a methodology for identifying pairwise eQTL effects on gene modules. POEM is specifically designed to achieve high performance in the case of additive joint effects. We applied POEM to transcription profiles measured in bone marrow-derived dendritic cells across a population of genotyped mice. Our study reveals widespread additive, trans-acting pairwise effects on gene modules, characterizes their organizational principles, and highlights high-order interconnections between modules within the immune signaling network. These analyses elucidate the central role of additive pairwise effect in regulatory circuits, and provide computational tools for future investigations into the interplay between eQTLs. Availability: The software described in this article is available at csgi.tau.ac.il/POEM/. PMID:27148351

Modulatory mechanisms of cortisol effects on emotional learning and memory: novel perspectives.

PubMed

van Ast, Vanessa A; Cornelisse, Sandra; Marin, Marie-France; Ackermann, Sandra; Garfinkel, Sarah N; Abercrombie, Heather C

2013-09-01

It has long been known that cortisol affects learning and memory processes. Despite a wealth of research dedicated to cortisol effects on learning and memory, the strength or even directionality of the effects often vary. A number of the factors that alter cortisol's effects on learning and memory are well-known. For instance, effects of cortisol can be modulated by emotional arousal and the memory phase under study. Despite great advances in understanding factors that explain variability in cortisol's effects, additional modulators of cortisol effects on memory exist that are less widely acknowledged in current basic experimental research. The goal of the current review is to disseminate knowledge regarding less well-known modulators of cortisol effects on learning and memory. Since several models for the etiology of anxiety, such as post-traumatic stress disorder (PTSD), incorporate stress and the concomitant release of cortisol as important vulnerability factors, enhanced understanding of mechanisms by which cortisol exerts beneficial as opposed to detrimental effects on memory is very important. Further elucidation of the factors that modulate (or alter) cortisol's effects on memory will allow reconciliation of seemingly inconsistent findings in the basic and clinical literatures. The present review is based on a symposium as part of the 42nd International Society of Psychoneuroendocrinology Conference, New York, USA, that highlighted some of those modulators and their underlying mechanisms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Modulation aware cluster size optimisation in wireless sensor networks

NASA Astrophysics Data System (ADS)

Sriram Naik, M.; Kumar, Vinay

2017-07-01

Wireless sensor networks (WSNs) play a great role because of their numerous advantages to the mankind. The main challenge with WSNs is the energy efficiency. In this paper, we have focused on the energy minimisation with the help of cluster size optimisation along with consideration of modulation effect when the nodes are not able to communicate using baseband communication technique. Cluster size optimisations is important technique to improve the performance of WSNs. It provides improvement in energy efficiency, network scalability, network lifetime and latency. We have proposed analytical expression for cluster size optimisation using traditional sensing model of nodes for square sensing field with consideration of modulation effects. Energy minimisation can be achieved by changing the modulation schemes such as BPSK, 16-QAM, QPSK, 64-QAM, etc., so we are considering the effect of different modulation techniques in the cluster formation. The nodes in the sensing fields are random and uniformly deployed. It is also observed that placement of base station at centre of scenario enables very less number of modulation schemes to work in energy efficient manner but when base station placed at the corner of the sensing field, it enable large number of modulation schemes to work in energy efficient manner.

Method for the substantial reduction of quenching effects in luminescence spectrometry

DOEpatents

Demas, James N.; Jones, Wesley M.; Keller, Richard A.

1989-01-01

Method for reducing quenching effects in analytical luminescence measurements. Two embodiments of the present invention are described which relate to a form of time resolution based on the amplitudes and phase shifts of modulated emission signals. In the first embodiment, the measured modulated emission signal is substantially independent of sample quenching at sufficiently high frequenices. In the second embodiment, the modulated amplitude and the phase shift between the emission signal and the excitation source are simultaneously measured. Using either method, the observed modulated amplitude may reduced to tis unquenched value.

Amplitudes of solar modulation of low energy cosmic rays

NASA Technical Reports Server (NTRS)

Von Rosenvinge, T. T.; Paizis, C.

1982-01-01

There have been differences of opinion regarding the origin and behavior of the solar modulation of galactic cosmic rays. It has been shown that the return to solar maximum intensity levels beginning in early 1978 was dominated by Forbush decreases. These Forbush decreases were caused by radially moving interplanetary shocks resulting from large solar flares. The present investigation is concerned with solar modulation effects which were observed during the previous solar minimum. The effects were associated with high-speed streams in the solar wind. These streams caused the formation of corotating interaction regions with both forward and reverse shocks. The modulation effects seen near earth are intimately connected with these shocks.

Thermal and other tests of photovoltaic modules performed in natural sunlight

NASA Technical Reports Server (NTRS)

Stultz, J. W.

1978-01-01

The bulk of the testing was the characterization of twenty-nine modules according to their nominal operating cell temperature (NOCT) and the effect on NOCT of changes in module design, various residential roof mounting configurations, and dirt accumulation. Other tests, often performed parallel with the NOCT measurements, evaluated the improvement in electrical performance by cooling the modules with water and by channeling the waste heat into a phase change material (wax). Electrical degradation resulting from the natural marriage of photovoltaic and solar water heating modules was also demonstrated. Cost effectiveness of each of these techniques are evaluated in light of the LSA cost goal of $0.50 per watt.

Improvement of modulation bandwidth in electroabsorption-modulated laser by utilizing the resonance property in bonding wire.

PubMed

Kwon, Oh Kee; Han, Young Tak; Baek, Yong Soon; Chung, Yun C

2012-05-21

We present and demonstrate a simple and cost-effective technique for improving the modulation bandwidth of electroabsorption-modulated laser (EML). This technique utilizes the RF resonance caused by the EML chip (i.e., junction capacitance) and bonding wire (i.e, wire inductance). We analyze the effects of the lengths of the bonding wires on the frequency responses of EML by using an equivalent circuit model. To verify this analysis, we package a lumped EML chip on the sub-mount and measure its frequency responses. The results show that, by using the proposed technique, we can increase the modulation bandwidth of EML from ~16 GHz to ~28 GHz.

Effect of Electrode Loss on the Dynamic Range of Linearized Directional Coupler Modulators

DTIC Science & Technology

2006-02-01

Coupler Modulators George A. Brost , Richard Michalak, Paul Payson, and Kevin Magde Abstract—Numerical simulations were used to study the effect of...RANGE OF LINEARIZED DIRECTIONAL COUPLER MODULATORS In-House N/A 62204F LINKI SN 01 George A. Brost , Richard Michalak, Paul Payson and Kevin Magde AFRL...Fazio Nash BROST et al.: EFFECT OF ELECTRODE LOSS ON THE DYNAMIC RANGE OF LINEARIZED DCMs 515 Fig. 1. Frequency dependence of SFDR for the 1 2 DCM (s

Evaluation of Temperature-Dependent Effective Material Properties and Performance of a Thermoelectric Module

NASA Astrophysics Data System (ADS)

Chien, Heng-Chieh; Chu, En-Ting; Hsieh, Huey-Lin; Huang, Jing-Yi; Wu, Sheng-Tsai; Dai, Ming-Ji; Liu, Chun-Kai; Yao, Da-Jeng

2013-07-01

We devised a novel method to evaluate the temperature-dependent effective properties of a thermoelectric module (TEM): Seebeck coefficient ( S m), internal electrical resistance ( R m), and thermal conductance ( K m). After calculation, the effective properties of the module are converted to the average material properties of a p- n thermoelectric pillar pair inside the module: Seebeck coefficient ( S TE), electrical resistivity ( ρ TE), and thermal conductivity ( k TE). For a commercial thermoelectric module (Altec 1091) chosen to verify the novel method, the measured S TE has a maximum value at bath temperature of 110°C; ρ TE shows a positive linear trend dependent on the bath temperature, and k TE increases slightly with increasing bath temperature. The results show the method to have satisfactory measurement performance in terms of practicability and reliability; the data for tests near 23°C agree with published values.

Heritability and molecular genetic basis of acoustic startle eye blink and affectively modulated startle response: A genome-wide association study

PubMed Central

VAIDYANATHAN, UMA; MALONE, STEPHEN M.; MILLER, MICHAEL B.; McGUE, MATT; IACONO, WILLIAM G.

2014-01-01

Acoustic startle responses have been studied extensively in relation to individual differences and psychopathology. We examined three indices of the blink response in a picture-viewing paradigm—overall startle magnitude across all picture types, and aversive and pleasant modulation scores—in 3,323 twins and parents. Biometric models and molecular genetic analyses showed that half the variance in overall startle was due to additive genetic effects. No single nucleotide polymorphism was genome-wide significant, but GRIK3 did produce a significant effect when examined as part of a candidate gene set. In contrast, emotion modulation scores showed little evidence of heritability in either biometric or molecular genetic analyses. However, in a genome-wide scan, PARP14 did produce a significant effect for aversive modulation. We conclude that, although overall startle retains potential as an endophenotype, emotion-modulated startle does not. PMID:25387708

Strain-Modulated Bandgap and Piezo-Resistive Effect in Black Phosphorus Field-Effect Transistors

NASA Astrophysics Data System (ADS)

Zhang, Zuocheng; Li, Likai; Horng, Jason; Wang, Nai Zhou; Yang, Fangyuan; Yu, Yijun; Zhang, Yu; Chen, Guorui; Watanabe, Kenji; Taniguchi, Takashi; Chen, Xian Hui; Wang, Feng; Zhang, Yuanbo

2017-10-01

Energy bandgap largely determines the optical and electronic properties of a semiconductor. Variable bandgap therefore makes versatile functionality possible in a single material. In layered material black phosphorus, the bandgap can be modulated by the number of layers; as a result, few-layer black phosphorus has discrete bandgap values that are relevant for opto-electronic applications in the spectral range from red, in monolayer, to mid-infrared in the bulk limit. Here, we further demonstrate continuous bandgap modulation by mechanical strain applied through flexible substrates. The strain-modulated bandgap significantly alters the charge transport in black phosphorus at room temperature; we for the first time observe a large piezo-resistive effect in black phosphorus field-effect transistors (FETs). The effect opens up opportunities for future development of electro-mechanical transducers based on black phosphorus, and we demonstrate strain gauges constructed from black phosphorus thin crystals.

Strain-Modulated Bandgap and Piezo-Resistive Effect in Black Phosphorus Field-Effect Transistors.

PubMed

Zhang, Zuocheng; Li, Likai; Horng, Jason; Wang, Nai Zhou; Yang, Fangyuan; Yu, Yijun; Zhang, Yu; Chen, Guorui; Watanabe, Kenji; Taniguchi, Takashi; Chen, Xian Hui; Wang, Feng; Zhang, Yuanbo

2017-10-11

Energy bandgap largely determines the optical and electronic properties of a semiconductor. Variable bandgap therefore makes versatile functionality possible in a single material. In layered material black phosphorus, the bandgap can be modulated by the number of layers; as a result, few-layer black phosphorus has discrete bandgap values that are relevant for optoelectronic applications in the spectral range from red, in monolayer, to mid-infrared in the bulk limit. Here, we further demonstrate continuous bandgap modulation by mechanical strain applied through flexible substrates. The strain-modulated bandgap significantly alters the density of thermally activated carriers; we for the first time observe a large piezo-resistive effect in black phosphorus field-effect transistors (FETs) at room temperature. The effect opens up opportunities for future development of electromechanical transducers based on black phosphorus, and we demonstrate an ultrasensitive strain gauge constructed from black phosphorus thin crystals.

Strategy difficulty effects in young and older adults' episodic memory are modulated by inter-stimulus intervals and executive control processes.

PubMed

Burger, Lucile; Uittenhove, Kim; Lemaire, Patrick; Taconnat, Laurence

2017-04-01

Efficient execution of strategies is crucial to memory performance and to age-related differences in this performance. Relative strategy complexity influences memory performance and aging effects on memory. Here, we aimed to further our understanding of the effects of relative strategy complexity by looking at the role of cognitive control functions and the time-course of the effects of relative strategy complexity. Thus, we manipulated inter-stimulus intervals (ISI) and assessed executive functions. Results showed that (a) performance as a function of the relative strategy difficulty of the current and previous trial was modulated by ISI, (b) these effects were modulated by inhibition capacities, and (c) significant age differences were found in the way ISI modulates relative strategy difficulty. These findings have important implications for understanding the relationships between aging, executive control, and strategy execution in episodic memory. Copyright © 2017 Elsevier B.V. All rights reserved.

In-situ comparison of thermal measurement technologies for interpretation of PV module temperature de-rating effects

NASA Astrophysics Data System (ADS)

Elwood, Teri; Bennett, Whit; Lai, Teh; Simmons-Potter, Kelly

2016-09-01

It is well known that the efficiency of a photovoltaic (PV) module is strongly impacted by its temperature such that higher temperatures lead to lower energy conversion efficiencies. An accurate measurement of the temperature de-rating effect, therefore, is vital to the correct interpretation of PV module performance under varied environmental conditions. The current work investigates and compares methods for performing measurements of module temperature both in the lab and in field-test environments. A comparison of several temperature measurement devices was made in order to establish the ideal sensor configuration for quantifying module operating temperature. Sensors were also placed in various locations along a string of up to eight photovoltaic modules to examine the variance in operating temperature with position in the string and within a larger array of strings.

Large Advanced Space Systems (LASS) computer-aided design program additions

NASA Technical Reports Server (NTRS)

Farrell, C. E.

1982-01-01

The LSS preliminary and conceptual design requires extensive iteractive analysis because of the effects of structural, thermal, and control intercoupling. A computer aided design program that will permit integrating and interfacing of required large space system (LSS) analyses is discussed. The primary objective of this program is the implementation of modeling techniques and analysis algorithms that permit interactive design and tradeoff studies of LSS concepts. Eight software modules were added to the program. The existing rigid body controls module was modified to include solar pressure effects. The new model generator modules and appendage synthesizer module are integrated (interfaced) to permit interactive definition and generation of LSS concepts. The mass properties module permits interactive specification of discrete masses and their locations. The other modules permit interactive analysis of orbital transfer requirements, antenna primary beam n, and attitude control requirements.

The role of optoelectronic feedback on Franz-Keldysh voltage modulation of transistor lasers

NASA Astrophysics Data System (ADS)

Chang, Chi-Hsiang; Chang, Shu-Wei; Wu, Chao-Hsin

2016-03-01

Possessing both the high-speed characteristics of heterojunction bipolar transistors (HBTs) and enhanced radiative recombination of quantum wells (QWs), the light-emitting transistor (LET) which operates in the regime of spontaneous emissions has achieved up to 4.3 GHz modulation bandwidth. A 40 Gbit/s transmission rate can be even achieved using transistor laser (TL). The transistor laser provides not only the current modulation but also direct voltage-controlled modulation scheme of optical signals via Franz-Keldysh (FK) photon-assisted tunneling effect. In this work, the effect of FK absorption on the voltage modulation of TLs is investigated. In order to analyze the dynamics and optical responses of voltage modulation in TLs, the conventional rate equations relevant to diode lasers (DLs) are first modified to include the FK effect intuitively. The theoretical results of direct-current (DC) and small-signal alternating-current (AC) characteristics of optical responses are both investigated. While the DC characteristics look physical, the intrinsic optical response of TLs under the FK voltage modulation shows an AC enhancement with a 20 dB peak, which however is not observed in experiment. A complete model composed of the intrinsic optical transfer function and an electrical transfer function fed back by optical responses is proposed to explain the behaviors of voltage modulation in TLs. The abnormal AC peak disappears through this optoelectronic feedback. With the electrical response along with FK-included photon-carrier rate equations taken into account, the complete voltage-controlled optical modulation response of TLs is demonstrated.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, Jeffrey Wayne; Pratt, Richard M

A modulated backscatter radio frequency identification device includes a diode detector configured to selectively modulate a reply signal onto an incoming continuous wave; communications circuitry configured to provide a modulation control signal to the diode detector, the diode detector being configured to modulate the reply signal in response to be modulation control signal; and circuitry configured to increase impedance change at the diode detector which would otherwise not occur because the diode detector rectifies the incoming continuous wave while modulating the reply signal, whereby reducing the rectified signal increases modulation depth by removing the reverse bias effects on impedance changes.more » Methods of improving depth of modulation in a modulated backscatter radio frequency identification device are also provided.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalavagunta, C; Lin, M; Snider, J

Purpose: To quantify the factors leading to thermoplastic mask bolus-associated-increased skin dose in head and neck IMRT/VMAT using EBT2 film. Methods: EBT2 film placed beneath a dual layer 3-point ORFIT head, neck and shoulder mask was used to test the effect of mask thickness, beam modulation, air gap, and beam obliquity on bolus effect. Mask thickness was varied based on the distribution of 1.6mm Orfilight layer on top of 2 mm Efficast layer. Beam modulation was varied by irradiating the film with an open field (no beam modulation) and a step and shoot field (beam modulation). Air gap between maskmore » and film was varied from 0 to 5mm. Beam obliquity was varied by irradiating the film at gantry angles of 0°, 35°, and 70°.Finally, film strips placed on a Rando phantom under an Orfit mask, in regions of expected high dose, were irradiated using 5 IMRT and 5 VMAT plans with various modulation levels (modulation factor 2 to 5) and the results were compared with those obtained placing OSLDs at the same locations. Results: An 18–34% increase in mask bolus effect was observed for three factors where the effect of beam obliquity ≥ beam modulation > mask thickness. No increase in mask bolus effect was observed for change in air gap. A 6–13% increase in dose due to mask bolus effect was observed on film strips. Conclusion: This work underlines the role of beam obliquity and beam modulation combined with thermoplastic mask thickness in increasing mask bolus-associated skin dose in head and neck IMRT/VMAT. One possible method of dose reduction, based on knowledge gained from this work, is inclusion of skin as an avoidance structure in treatment planning. Another approach is to design a mask with the least amount of thermoplastic material necessary for immobilization.« less

Aging effects in sequential modulations of poorer-strategy effects during execution of memory strategies.

PubMed

Hinault, Thomas; Lemaire, Patrick; Touron, Dayna

2017-02-01

In this study, we asked young adults and older adults to encode pairs of words. For each item, they were told which strategy to use, interactive imagery or rote repetition. Data revealed poorer-strategy effects in both young adults and older adults: Participants obtained better performance when executing better strategies (i.e., interactive-imagery strategy to encode pairs of concrete words; rote-repetition strategy on pairs of abstract words) than with poorer strategies (i.e., interactive-imagery strategy on pairs of abstract words; rote-repetition strategy on pairs of concrete words). Crucially, we showed that sequential modulations of poorer-strategy effects (i.e., poorer-strategy effects being larger when previous items were encoded with better relative to poorer strategies), previously demonstrated in arithmetic, generalise to memory strategies. We also found reduced sequential modulations of poorer-strategy effects in older adults relative to young adults. Finally, sequential modulations of poorer-strategy effects correlated with measures of cognitive control processes, suggesting that these processes underlie efficient trial-to-trial modulations during strategy execution. Differences in correlations with cognitive control processes were also found between older adults and young adults. These findings have important implications regarding mechanisms underlying memory strategy execution and age differences in memory performance.

Effects of radial envelope modulations on the collisionless trapped-electron mode in tokamak plasmas

NASA Astrophysics Data System (ADS)

Chen, Hao-Tian; Chen, Liu

2018-05-01

Adopting the ballooning-mode representation and including the effects of radial envelope modulations, we have derived the corresponding linear eigenmode equation for the collisionless trapped-electron mode in tokamak plasmas. Numerical solutions of the eigenmode equation indicate that finite radial envelope modulations can affect the linear stability properties both quantitatively and qualitatively via the significant modifications in the corresponding eigenmode structures.

An Analysis of the Cost and Performance of Photovoltaic Systems as a Function of Module Area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horowitz, Kelsey A.W.; Fu, Ran; Silverman, Tim

We investigate the potential effects of module area on the cost and performance of photovoltaic systems. Applying a bottom-up methodology, we analyzed the costs associated with mc-Si and thin-film modules and systems as a function of module area. We calculate a potential for savings of up to $0.04/W, $0.10/W, and $0.13/W in module manufacturing costs for mc-Si, CdTe, and CIGS respectively, with large area modules. We also find that an additional $0.05/W savings in balance-of-systems costs may be achieved. However, these savings are dependent on the ability to maintain efficiency and manufacturing yield as area scales. Lifetime energy yield mustmore » also be maintained to realize reductions in the levelized cost of energy. We explore the possible effects of module size on efficiency and energy production, and find that more research is required to understand these issues for each technology. Sensitivity of the $/W cost savings to module efficiency and manufacturing yield is presented. We also discuss non-cost barriers to adoption of large area modules.« less

Development of training modules for magnetic particle inspection

NASA Astrophysics Data System (ADS)

Kosaka, Daigo; Eisenmann, David J.; Enyart, Darrel; Nakagawa, Norio; Lo, Chester; Orman, David

2015-03-01

Magnetic particle inspection (MPI) is a nondestructive evaluation technique used with ferromagnetic materials. Although the application of this method may appear straightforward, MPI combines the complicated nature of electromagnetics, metallurgical material effects, fluid-particle motion dynamics, and physiological human factors into a single inspection. To fully appreciate industry specifications such as ASTM E-1444, users should develop a basic understanding of the many factors that are involved in MPI. We have developed a series of MPI training modules that are aimed at addressing this requirement. The modules not only offer qualitative explanations, but also show quantitative explanations in terms of measurement and numerical simulation data in many instances. There are five modules in all. Module ♯1 shows characteristics of waveforms and magnetizing methods. This allows MPI practitioners to make optimum choice of waveform and magnetizing method. Module ♯2 explains how material properties relate to the magnetic characteristics. Module ♯3 shows the strength of the excitation field or the flux leakage from a crack and how it compares to the detectability of a crack by MPI. Module ♯4 shows how specimen status may influence defect detection. Module ♯5 shows the effects of particle properties on defect detection.

The Efficacy of IRIS "STAR Legacy" Modules under Different Instructional Conditions

ERIC Educational Resources Information Center

Sayeski, Kristin L.; Hamilton-Jones, Bethany; Oh, Susan

2015-01-01

The vast majority of special education teacher preparation programs in the United States incorporate the IRIS Center's "STAR Legacy" modules into their coursework. Given the diversity of module content and ways in which the modules are employed, the purpose of this study was to explore the potential mediating effects of instructional…

Hands-On Learning Modules for Interdisciplinary Environments: An Example with a Focus on Weather Radar Applications

ERIC Educational Resources Information Center

Chilson, P. B.; Yeary, M. B.

2012-01-01

Learning modules provide an effective means of encouraging cognition and active learning. This paper discusses several such modules that have been developed within a course on weather radar applications intended for students from Electrical Engineering and Meteorology. The modules were designed both to promote interdisciplinary exchange between…

47 CFR 90.242 - Travelers' information stations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the modulation limiter and the modulated stage. At audio frequencies between 3 kHz and 20 kHz this...' information stations. (a) The frequencies 530 through 1700 kHz in 10 kHz increments may be assigned to the... consideration of possible cross-modulation and inter-modulation interference effects which may result from the...

Enhanced spatial near-infrared modulation of graphene-loaded perfect absorbers using plasmonic nanoslits.

PubMed

Cai, Yijun; Zhu, Jinfeng; Liu, Qing Huo; Lin, Timothy; Zhou, Jianyang; Ye, Longfang; Cai, Zhiping

2015-12-14

Modulating spatial near-infrared light for ultra-compact electro-optic devices is a critical issue in optical communication and imaging applications. To date, spatial near-infrared modulators based on graphene have been reported, but they showed limited modulation effects due to the relatively weak light-graphene interaction. In combination with graphene and metallic nanoslits, we design a kind of ultrathin near-infrared perfect absorber with enhanced spatial modulation effects and independence on a wide range of incident angles. The modulated spectral shift of central wavelength is up to 258.2 nm in the near-infrared range, which is more promising in applications than state-of-the-art devices. The modulation enhancement is attributed to the plasmonic nanoslit mode, in which the optical electric field is highly concentrated in the deep subwavelength scale and the light-graphene interaction is significantly strengthened. The physical insight is deeply revealed by a combination of equivalent circuit and electromagnetic field analysis. The design principles are not only crucial for spatial near-infrared modulators, but also provide a key guide for developing active near-infrared patch nanoantennas based on graphene.

Low cost solar array project production process and equipment task. A Module Experimental Process System Development Unit (MEPSDU)

NASA Technical Reports Server (NTRS)

1981-01-01

Technical readiness for the production of photovoltaic modules using single crystal silicon dendritic web sheet material is demonstrated by: (1) selection, design and implementation of solar cell and photovoltaic module process sequence in a Module Experimental Process System Development Unit; (2) demonstration runs; (3) passing of acceptance and qualification tests; and (4) achievement of a cost effective module.

Extension of wavelength-modulation spectroscopy to large modulation depth for diode laser absorption measurements in high-pressure gases

NASA Astrophysics Data System (ADS)

Li, Hejie; Rieker, Gregory B.; Liu, Xiang; Jeffries, Jay B.; Hanson, Ronald K.

2006-02-01

Tunable diode laser absorption measurements at high pressures by use of wavelength-modulation spectroscopy (WMS) require large modulation depths for optimum detection of molecular absorption spectra blended by collisional broadening or dense spacing of the rovibrational transitions. Diode lasers have a large and nonlinear intensity modulation when the wavelength is modulated over a large range by injection-current tuning. In addition to this intensity modulation, other laser performance parameters are measured, including the phase shift between the frequency modulation and the intensity modulation. Following published theory, these parameters are incorporated into an improved model of the WMS signal. The influence of these nonideal laser effects is investigated by means of wavelength-scanned WMS measurements as a function of bath gas pressure on rovibrational transitions of water vapor near 1388 nm. Lock-in detection of the magnitude of the 2f signal is performed to remove the dependence on detection phase. We find good agreement between measurements and the improved model developed for the 2f component of the WMS signal. The effects of the nonideal performance parameters of commercial diode lasers are especially important away from the line center of discrete spectra, and these contributions become more pronounced for 2f signals with the large modulation depths needed for WMS at elevated pressures.

Coherent modulation of stimulus colour can affect visually induced self-motion perception.

PubMed

Nakamura, Shinji; Seno, Takeharu; Ito, Hiroyuki; Sunaga, Shoji

2010-01-01

The effects of dynamic colour modulation on vection were investigated to examine whether perceived variation of illumination affects self-motion perception. Participants observed expanding optic flow which simulated their forward self-motion. Onset latency, accumulated duration, and estimated magnitude of the self-motion were measured as indices of vection strength. Colour of the dots in the visual stimulus was modulated between white and red (experiment 1), white and grey (experiment 2), and grey and red (experiment 3). The results indicated that coherent colour oscillation in the visual stimulus significantly suppressed the strength of vection, whereas incoherent or static colour modulation did not affect vection. There was no effect of the types of the colour modulation; both achromatic and chromatic modulations turned out to be effective in inhibiting self-motion perception. Moreover, in a situation where the simulated direction of a spotlight was manipulated dynamically, vection strength was also suppressed (experiment 4). These results suggest that observer's perception of illumination is critical for self-motion perception, and rapid variation of perceived illumination would impair the reliabilities of visual information in determining self-motion.

Recovery of Large Angular Scale CMB Polarization for Instruments Employing Variable-Delay Polarization Modulators

NASA Technical Reports Server (NTRS)

Miller, N. J.; Chuss, D. T.; Marriage, T. A.; Wollack, E. J.; Appel, J. W.; Bennett, C. L.; Eimer, J.; Essinger-Hileman, T.; Fixsen, D. J.; Harrington, K.;

Opposite Effects of Stress on Pain Modulation Depend on the Magnitude of Individual Stress Response.

PubMed

Geva, Nirit; Defrin, Ruth

2018-04-01

The effect of acute stress on pain threshold and intolerance threshold are reported as producing either hypoalgesia or hyperalgesia. Yet, the contribution of individual stress reactivity in this respect has not been established. The aim was to test 2 pain modulation paradigms under acute stress manipulation, to our knowledge, for the first time, to study whether stress differentially affects pain modulation, and whether the effect is related to individual stress response. Participants were 31 healthy subjects. Conditioned pain modulation (CPM) and pain adaptation were measured before and after inducing an acute stress response using the Montreal Imaging Stress Task. Subjects' stress response was evaluated according to salivary cortisol, autonomic function, and perceived stress and anxiety. The Montreal Imaging Stress Task induced a validated stress response. On a group level, stress induced reduction in CPM magnitude and increase in pain adaptation compared with baseline. These responses correlated with stress reactivity. When the group was subdivided according to stress reactivity, only high stress responders exhibited reduced CPM whereas only low stress responders exhibited increased pain adaptation. The results suggest that acute stress may induce opposite effects on pain modulation, depending on individual stress reactivity magnitude, with an advantage to low stress responders. This study evaluated the effect of acute stress on pain modulation. Pain modulation under stress is affected by individual stress responsiveness; decreased CPM occurs in high stress responders whereas increased pain adaptation occurs in low stress responders. Identification of high stress responders may promote better pain management. Copyright © 2017 The American Pain Society. Published by Elsevier Inc. All rights reserved.

Wide-field imaging through scattering media by scattered light fluorescence microscopy

NASA Astrophysics Data System (ADS)

Zhou, Yulan; Li, Xun

2017-08-01

To obtain images through scattering media, scattered light fluorescence (SLF) microscopy that utilizes the optical memory effect has been developed. However, the small field of view (FOV) of SLF microscopy limits its application. In this paper, we have introduced a re-modulation method to achieve wide-field imaging through scattering media by SLF microscopy. In the re-modulation method, to raster scan the focus across the object plane, the incident wavefront is re-modulated via a spatial light modulator (SLM) in the updated phase compensation calculated using the optimized iterative algorithm. Compared with the conventional optical memory effect method, the re-modulation method can greatly increase the FOV of a SLF microscope. With the phase compensation theoretically calculated, the process of updating the phase compensation of a high speed SLM is fast. The re-modulation method does not increase the imaging time. The re-modulation method is, therefore, expected to make SLF microscopy have much wider applications in biology, medicine and physiology.

Modulation of high frequency noise by engine tones of small boats.

PubMed

Pollara, Alexander; Sutin, Alexander; Salloum, Hady

2017-07-01

The effect of modulation of high frequency ship noise by propeller rotation frequencies is well known. This modulation is observed with the Detection of Envelope Modulation on Noise (DEMON) algorithm. Analysis of the DEMON spectrum allows the revolutions per minute and number of blades of the propeller to be determined. This work shows that the high frequency noise of a small boat can also be modulated by engine frequencies. Prior studies have not reported high frequency noise amplitude modulated at engine frequencies. This modulation is likely produced by bubbles from the engine exhaust system.

Method for the substantial reduction of quenching effects in luminescence spectrometry

DOEpatents

Demas, J.N.; Jones, W.M.; Keller, R.A.

1987-06-26

Method for reducing quenching effects in analytical luminescence measurements. Two embodiments of the present invention are described which relate to a form of time resolution based on the amplitudes and phase shifts of modulated emission signals. In the first embodiment, the measured modulated emission signal is substantially independent of sample quenching at sufficiently high frequencies. In the second embodiment, the modulated amplitude and the phase shift between the emission signal and the excitation source are simultaneously measured. Using either method, the observed modulated amplitude may be reduced to its unquenched value. 3 figs.

The Intensity Modulation of the Fluorescent Line by a Finite Light Speed Effect in Accretion-powered X-Ray Pulsars

NASA Astrophysics Data System (ADS)

Yoshida, Yuki; Kitamoto, Shunji; Hoshino, Akio

2017-11-01

The X-ray line diagnostic method is a powerful tool for an investigation of plasma around accretion-powered X-ray pulsars. We point out an apparent intensity modulation of emission lines, with their rotation period of neutron stars, due to the finite speed of light (we call this effect the “finite light speed effect”) if the line emission mechanism is a kind of reprocessing, such as fluorescence or recombination after ionization by X-ray irradiation from pulsars. The modulation amplitude is determined by the size of the emission region, which is in competition with the smearing effect by the light crossing time in the emission region. This is efficient if the size of the emission region is roughly comparable to that of the rotation period multiplied by the speed of light. We apply this effect to a symbiotic X-ray pulsar, GX 1+4, where a spin modulation of the intense iron line of which has been reported. The finite light speed effect can explain the observed intensity modulation if its fluorescent region is the size of ˜ {10}12 cm.

Engineered TAL Effector modulators for the large-scale gain-of-function screening

PubMed Central

Zhang, Hanshuo; Li, Juan; Hou, Sha; Wang, Gancheng; Jiang, Mingjun; Sun, Changhong; Hu, Xiongbing; Zhuang, Fengfeng; Dai, Zhifei; Dai, Junbiao; Xi, Jianzhong Jeff

2014-01-01

Recent effective use of TAL Effectors (TALEs) has provided an important approach to the design and synthesis of sequence-specific DNA-binding proteins. However, it is still a challenging task to design and manufacture effective TALE modulators because of the limited knowledge of TALE–DNA interactions. Here we synthesized more than 200 TALE modulators and identified two determining factors of transcription activity in vivo: chromatin accessibility and the distance from the transcription start site. The implementation of these modulators in a gain-of-function screen was successfully demonstrated for four cell lines in migration/invasion assays and thus has broad relevance in this field. Furthermore, a novel TALE–TALE modulator was developed to transcriptionally inhibit target genes. Together, these findings underscore the huge potential of these TALE modulators in the study of gene function, reprogramming of cellular behaviors, and even clinical investigation. PMID:24939900

Attentional Modulation of Emotional Conflict Processing with Flanker Tasks

PubMed Central

Zhou, Pingyan; Liu, Xun

2013-01-01

Emotion processing has been shown to acquire priority by biasing allocation of attentional resources. Aversive images or fearful expressions are processed quickly and automatically. Many existing findings suggested that processing of emotional information was pre-attentive, largely immune from attentional control. Other studies argued that attention gated the processing of emotion. To tackle this controversy, the current study examined whether and to what degrees attention modulated processing of emotion using a stimulus-response-compatibility (SRC) paradigm. We conducted two flanker experiments using color scale faces in neutral expressions or gray scale faces in emotional expressions. We found SRC effects for all three dimensions (color, gender, and emotion) and SRC effects were larger when the conflicts were task relevant than when they were task irrelevant, suggesting that conflict processing of emotion was modulated by attention, similar to those of color and face identity (gender). However, task modulation on color SRC effect was significantly greater than that on gender or emotion SRC effect, indicating that processing of salient information was modulated by attention to a lesser degree than processing of non-emotional stimuli. We proposed that emotion processing can be influenced by attentional control, but at the same time salience of emotional information may bias toward bottom-up processing, rendering less top-down modulation than that on non-emotional stimuli. PMID:23544155

Attentional modulation of emotional conflict processing with flanker tasks.

PubMed

Zhou, Pingyan; Liu, Xun

2013-01-01

Emotion processing has been shown to acquire priority by biasing allocation of attentional resources. Aversive images or fearful expressions are processed quickly and automatically. Many existing findings suggested that processing of emotional information was pre-attentive, largely immune from attentional control. Other studies argued that attention gated the processing of emotion. To tackle this controversy, the current study examined whether and to what degrees attention modulated processing of emotion using a stimulus-response-compatibility (SRC) paradigm. We conducted two flanker experiments using color scale faces in neutral expressions or gray scale faces in emotional expressions. We found SRC effects for all three dimensions (color, gender, and emotion) and SRC effects were larger when the conflicts were task relevant than when they were task irrelevant, suggesting that conflict processing of emotion was modulated by attention, similar to those of color and face identity (gender). However, task modulation on color SRC effect was significantly greater than that on gender or emotion SRC effect, indicating that processing of salient information was modulated by attention to a lesser degree than processing of non-emotional stimuli. We proposed that emotion processing can be influenced by attentional control, but at the same time salience of emotional information may bias toward bottom-up processing, rendering less top-down modulation than that on non-emotional stimuli.

Binaural Interaction Effects of 30-50 Hz Auditory Steady State Responses.

PubMed

Gransier, Robin; van Wieringen, Astrid; Wouters, Jan

Auditory stimuli modulated by modulation frequencies within the 30 to 50 Hz region evoke auditory steady state responses (ASSRs) with high signal to noise ratios in adults, and can be used to determine the frequency-specific hearing thresholds of adults who are unable to give behavioral feedback reliably. To measure ASSRs as efficiently as possible a multiple stimulus paradigm can be used, stimulating both ears simultaneously. The response strength of 30 to 50Hz ASSRs is, however, affected when both ears are stimulated simultaneously. The aim of the present study is to gain insight in the measurement efficiency of 30 to 50 Hz ASSRs evoked with a 2-ear stimulation paradigm, by systematically investigating the binaural interaction effects of 30 to 50 Hz ASSRs in normal-hearing adults. ASSRs were obtained with a 64-channel EEG system in 23 normal-hearing adults. All participants participated in one diotic, multiple dichotic, and multiple monaural conditions. Stimuli consisted of a modulated one-octave noise band, centered at 1 kHz, and presented at 70 dB SPL. The diotic condition contained 40 Hz modulated stimuli presented to both ears. In the dichotic conditions, the modulation frequency of the left ear stimulus was kept constant at 40 Hz, while the stimulus at the right ear was either the unmodulated or modulated carrier. In case of the modulated carrier, the modulation frequency varied between 30 and 50 Hz in steps of 2 Hz across conditions. The monaural conditions consisted of all stimuli included in the diotic and dichotic conditions. Modulation frequencies ≥36 Hz resulted in prominent ASSRs in all participants for the monaural conditions. A significant enhancement effect was observed (average: ~3 dB) in the diotic condition, whereas a significant reduction effect was observed in the dichotic conditions. There was no distinct effect of the temporal characteristics of the stimuli on the amount of reduction. The attenuation was in 33% of the cases >3 dB for ASSRs evoked with modulation frequencies ≥40 Hz and 50% for ASSRs evoked with modulation frequencies ≤36 Hz. Binaural interaction effects as observed in the diotic condition are similar to the binaural interaction effects of middle latency responses as reported in the literature, suggesting that these responses share a same underlying mechanism. Our data also indicated that 30 to 50 Hz ASSRs are attenuated when presented dichotically and that this attenuation is independent of the stimulus characteristics as used in the present study. These findings are important as they give insight in how binaural interaction affects the measurement efficiency. The 2-ear stimulation paradigm of the present study was, for the most optimal modulation frequencies (i.e., ≥40 Hz), more efficient than a 1-ear sequential stimulation paradigm in 66% of the cases.

Effects of nicotine in combination with drugs described as positive allosteric nicotinic acetylcholine receptor modulators in vitro: discriminative stimulus and hypothermic effects in mice.

PubMed

Moerke, Megan J; de Moura, Fernando B; Koek, Wouter; McMahon, Lance R

2016-09-05

Some drugs that are positive allosteric nAChR modulators in vitro, desformylflustrabromine (dFBr), PNU-120596 and LY 2087101, have not been fully characterized in vivo. These drugs were examined for their capacity to share or modify the hypothermic and discriminative stimulus effects of nicotine (1mg/kg s.c.) in male C57Bl/6J mice. Nicotine, dFBr, and PNU-120596 produced significant hypothermia, whereas LY 2087101 (up to 100mg/kg) did not. Nicotine dose-dependently increased nicotine-appropriate responding and decreased response rate; the respective ED50 values were 0.56mg/kg and 0.91mg/kg. The modulators produced no more than 38% nicotine-appropriate responding up to doses that disrupted operant responding. Rank order potency was the same for hypothermia and rate-decreasing effects: nicotine>dFBr>PNU-120596=LY 2087101. Mecamylamine and the α4β2 nAChR antagonist dihydro-β-erythroidine, but not the α7 antagonist methyllycaconitine, antagonized the hypothermic effects of nicotine. In contrast, mecamylamine did not antagonize the hypothermic effects of the modulators. The combined discriminative stimulus effects of DFBr and nicotine were synergistic, whereas the combined hypothermic effects of nicotine with either dFBr or PNU-120596 were infra-additive. PNU-120596 did not modify the nicotine discriminative stimulus, and LY 2087101 did not significantly modify either effect of nicotine. Positive modulation of nicotine at nAChRs by PNU-120596 and LY 2087101 in vitro does not appear to confer enhancement of the nAChR-mediated hypothermic or discriminative stimulus effects of nicotine. However, dFBr appears to be a positive allosteric modulator of some behavioral effects of nicotine at doses of dFBr smaller than the doses producing unwanted effects (e.g. hypothermia) through non-nAChR mechanisms. Copyright © 2016 Elsevier B.V. All rights reserved.

Sequential Modulations in a Combined Horizontal and Vertical Simon Task: Is There ERP Evidence for Feature Integration Effects?

PubMed Central

Hoppe, Katharina; Küper, Kristina; Wascher, Edmund

2017-01-01

In the Simon task, participants respond faster when the task-irrelevant stimulus position and the response position are corresponding, for example on the same side, compared to when they have a non-corresponding relation. Interestingly, this Simon effect is reduced after non-corresponding trials. Such sequential effects can be explained in terms of a more focused processing of the relevant stimulus dimension due to increased cognitive control, which transfers from the previous non-corresponding trial (conflict adaptation effects). Alternatively, sequential modulations of the Simon effect can also be due to the degree of trial-to-trial repetitions and alternations of task features, which is confounded with the correspondence sequence (feature integration effects). In the present study, we used a spatially two-dimensional Simon task with vertical response keys to examine the contribution of adaptive cognitive control and feature integration processes to the sequential modulation of the Simon effect. The two-dimensional Simon task creates correspondences in the vertical as well as in the horizontal dimension. A trial-by-trial alternation of the spatial dimension, for example from a vertical to a horizontal stimulus presentation, generates a subset containing no complete repetitions of task features, but only complete alternations and partial repetitions, which are equally distributed over all correspondence sequences. In line with the assumed feature integration effects, we found sequential modulations of the Simon effect only when the spatial dimension repeated. At least for the horizontal dimension, this pattern was confirmed by the parietal P3b, an event-related potential that is assumed to reflect stimulus–response link processes. Contrary to conflict adaptation effects, cognitive control, measured by the fronto-central N2 component of the EEG, was not sequentially modulated. Overall, our data provide behavioral as well as electrophysiological evidence for feature integration effects contributing to sequential modulations of the Simon effect. PMID:28713305

Effects of nicotine in combination with drugs described as positive allosteric nicotinic acetylcholine receptor modulators in vitro: discriminative stimulus and hypothermic effects in mice

PubMed Central

Moerke, Megan J.; de Moura, Fernando B.; Koek, Wouter; McMahon, Lance R.

2016-01-01

Some drugs that are positive allosteric nAChR modulators in vitro, desformylflustrabromine (dFBr), PNU-120596 and LY 2087101, have not been fully characterized in vivo. These drugs were examined for their capacity to share or modify the hypothermic and discriminative stimulus effects of nicotine (1 mg/kg s.c.) in male C57Bl/6J mice. Nicotine, dFBr, and PNU-120596 produced significant hypothermia, whereas LY 2087101 (up to 100 mg/kg) did not. Nicotine dose-dependently increased nicotine-appropriate responding and decreased response rate; the respective ED50 values were 0.56 mg/kg and 0.91 mg/kg. The modulators produced no more than 38% nicotine-appropriate responding up to doses that disrupted operant responding. Rank order potency was the same for hypothermia and rate-decreasing effects: nicotine>dFBr>PNU-120596=LY 2087101. Mecamylamine and the α4β2 nAChR antagonist dihydro-β-erythroidine, but not the α7 antagonist methyllycaconitine, antagonized the hypothermic effects of nicotine. In contrast, mecamylamine did not antagonize the hypothermic effects of the modulators. The combined discriminative stimulus effects of DFBr and nicotine were synergistic, whereas the combined hypothermic effects of nicotine with either dFBr or PNU-120596 were infra-additive. PNU-120596 did not modify the nicotine discriminative stimulus, and LY 2087101 did not significantly modify either effect of nicotine. Positive modulation of nicotine at nAChRs by PNU-120596 and LY 2087101 in vitro does not appear to confer enhancement of the nAChR-mediated hypothermic or discriminative stimulus effects of nicotine. However, dFBr appears to be a positive allosteric modulator of some behavioral effects of nicotine at doses of dFBr smaller than the doses producing unwanted effects (e.g. hypothermia) through non-nAChR mechanisms. PMID:27238974

Sequential Modulations in a Combined Horizontal and Vertical Simon Task: Is There ERP Evidence for Feature Integration Effects?

PubMed

Hoppe, Katharina; Küper, Kristina; Wascher, Edmund

2017-01-01

In the Simon task, participants respond faster when the task-irrelevant stimulus position and the response position are corresponding, for example on the same side, compared to when they have a non-corresponding relation. Interestingly, this Simon effect is reduced after non-corresponding trials. Such sequential effects can be explained in terms of a more focused processing of the relevant stimulus dimension due to increased cognitive control, which transfers from the previous non-corresponding trial (conflict adaptation effects). Alternatively, sequential modulations of the Simon effect can also be due to the degree of trial-to-trial repetitions and alternations of task features, which is confounded with the correspondence sequence (feature integration effects). In the present study, we used a spatially two-dimensional Simon task with vertical response keys to examine the contribution of adaptive cognitive control and feature integration processes to the sequential modulation of the Simon effect. The two-dimensional Simon task creates correspondences in the vertical as well as in the horizontal dimension. A trial-by-trial alternation of the spatial dimension, for example from a vertical to a horizontal stimulus presentation, generates a subset containing no complete repetitions of task features, but only complete alternations and partial repetitions, which are equally distributed over all correspondence sequences. In line with the assumed feature integration effects, we found sequential modulations of the Simon effect only when the spatial dimension repeated. At least for the horizontal dimension, this pattern was confirmed by the parietal P3b, an event-related potential that is assumed to reflect stimulus-response link processes. Contrary to conflict adaptation effects, cognitive control, measured by the fronto-central N2 component of the EEG, was not sequentially modulated. Overall, our data provide behavioral as well as electrophysiological evidence for feature integration effects contributing to sequential modulations of the Simon effect.

Plasma based optical guiding of an amplitude-modulated electromagnetic beam

NASA Astrophysics Data System (ADS)

Singh, Mamta; Gupta, D. N.

2015-06-01

We propose the stronger optical guiding of an electromagnetic beam in a plasma by considering the amplitude modulation of the fundamental beam. With the advent of high power source of electromagnetic radiation, the electron velocity in a plasma may become quite large (comparable to the light velocity in free space). Thus, the effect of relativistic mass variation must be taken into account. The relativistic effect of the laser propagation in a plasma leads to self-focusing because of the dielectric constant of a plasma being an increasing function of the intensity. The ponderomotive force of the laser beam pushes the electrons out of the region of high intensity, which reduces the local electron density and increases the plasma dielectric function further, leading to even more selffocusing of the laser. In this work, we consider a short pulse laser of finite spot size as an amplitude modulation in time. Our findings show an efficient optical guiding mechanism based on amplitude modulation signal propagation in plasmas. Medium nonlinearity becomes stronger if an amplitude modulated beam is introduced, which contributes significantly in laser guiding in plasmas. Furthermore, the rate of laser self-focusing is increased with modulation index due the fact of stronger Kerr effect. The study related to amplitude modulated optical signal may be useful for communication technology.

Development of a Flipped Medical School Dermatology Module.

PubMed

Fox, Joshua; Faber, David; Pikarsky, Solomon; Zhang, Chi; Riley, Richard; Mechaber, Alex; O'Connell, Mark; Kirsner, Robert S

2017-05-01

The flipped classroom module incorporates independent study in advance of in-class instructional sessions. It is unproven whether this methodology is effective within a medical school second-year organ system module. We report the development, implementation, and effectiveness of the flipped classroom methodology in a second-year medical student dermatology module at the University of Miami Leonard M. Miller School of Medicine. In a retrospective cohort analysis, we compared attitudinal survey data and mean scores for a 50-item multiple-choice final examination of the second-year medical students who participated in this 1-week flipped course with those of the previous year's traditional, lecture-based course. Each group comprised nearly 200 students. Students' age, sex, Medical College Admission Test scores, and undergraduate grade point averages were comparable between the flipped and traditional classroom students. The flipped module students' mean final examination score of 92.71% ± 5.03% was greater than that of the traditional module students' 90.92% ± 5.51% ( P < 0.001) score. Three of the five most commonly missed questions were identical between the two cohorts. The majority of students preferred the flipped methodology to attending live lectures or watching previously recorded lectures. The flipped classroom can be an effective instructional methodology for a medical school second-year organ system module.

Down-modulation of receptors for phorbol ester tumor promoter in primary epidermal cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Solanki, V.; Slaga, T.J.

1982-01-01

The specific (20-/sup 3/H)phorbol 12,13-dibutyrate ((/sup 3/H)PDBu) binding to intact epidermal cells displayed the phenomenon of down-modulation, i.e., the specific binding of (/sup 3/H)PDBu to its receptors on primary epidermal cells reached a maximum within 1 h and steadily declined thereafter. The apparent down-modulation of radiolabel resulted from a partial loss in the total number of receptors; the affinity of receptors for the ligand was essentially unchanged. A number of agents such as chloroquine, methylamine, or arginine which are known to prevent clustering, down-modulation, and/or internalization of several hormone receptors did not affect the down-modulation of phorbol ester receptors. Furthermore,more » cycloheximide had no effect either on down-modulation or on the binding capacity of cells. The surface binding capacity of down-modulated cells following a 90-min incubation with unlabeled ligand was almost returned to normal within 1 h. The effect of the antidepressant drug chlorpromazine, which is known to interact with calmodulin, on (/sup 3/H)PDBu binding was also investigated. Our data indicate that the effect of chlorpromazine on (/sup 3/H)PDBu binding is probably unrelated to its calmodulin-binding activity.« less

A Module-Based Environmental Science Course for Teaching Ecology to Non-Majors

ERIC Educational Resources Information Center

Smith, Geoffrey R.

2010-01-01

Using module-based courses has been suggested to improve undergraduate science courses. A course based around a series of modules focused on major environmental issues might be an effective way to teach non-science majors about ecology and ecology's role in helping to solve environmental problems. I have used such a module-based environmental…

Liquid-crystals electro-optic modulator based on electrohydrodynamic effects.

PubMed

Muriel, M A; Martin-Pereda, J A

1980-11-01

A new method of light modulation is reported. This method is based on the electro-optical properties of nematic materials and on the use of a new wedge structure. The advantages of this structure are the possibility of modulating nonpolarized light and the improved signal-to-noise ratio. The highest modulating frequency obtained is 25 kHz.

Effects of a Science Education Module on Attitudes towards Modern Biotechnology of Secondary School Students

ERIC Educational Resources Information Center

Klop, Tanja; Severiens, Sabine E.; Knippels, Marie-Christine P. J.; van Mil, Marc H. W.; Ten Dam, Geert T. M.

2010-01-01

This article evaluated the impact of a four-lesson science module on the attitudes of secondary school students. This science module (on cancer and modern biotechnology) utilises several design principles, related to a social constructivist perspective on learning. The expectation was that the module would help students become more articulate in…

The influence of plan modulation on the interplay effect in VMAT liver SBRT treatments.

PubMed

Hubley, Emily; Pierce, Greg

2017-08-01

Volumetric modulated arc therapy (VMAT) uses multileaf collimator (MLC) leaves, gantry speed, and dose rate to modulate beam fluence, producing the highly conformal doses required for liver radiotherapy. When targets that move with respiration are treated with a dynamic fluence, there exists the possibility for interplay between the target and leaf motions. This study employs a novel motion simulation technique to determine if VMAT liver SBRT plans with an increase in MLC leaf modulation are more susceptible to dosimetric differences in the GTV due to interplay effects. For ten liver SBRT patients, two VMAT plans with different amounts of MLC leaf modulation were created. Motion was simulated using a random starting point in the respiratory cycle for each fraction. To isolate the interplay effect, motion was also simulated using four specific starting points in the respiratory cycle. The dosimetric differences caused by different starting points were examined by subtracting resultant dose distributions from each other. When motion was simulated using random starting points for each fraction, or with specific starting points, there were significantly more dose differences in the GTV (maximum 100cGy) for more highly modulated plans, but the overall plan quality was not adversely affected. Plans with more MLC leaf modulation are more susceptible to interplay effects, but dose differences in the GTV are clinically negligible in magnitude. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Effects of particle drifts on the solar modulation of galactic cosmic rays

NASA Technical Reports Server (NTRS)

Jokipii, J. R.; Levy, E. H.

1977-01-01

Gradient and curvature drifts in an Archimedean-spiral magnetic field are shown to produce a significant effect on the modulation of galactic cosmic rays by the solar wind. The net modulation, heliocentric radial gradient, and average energy change of particles which reach the inner solar system are significantly reduced. The effects of drifts are due to the fact that cosmic rays for which the drift velocity is comparable to the wind velocity or larger, have more rapid access to the inner solar system than in the absence of drifts.

[Study for lung sound acquisition module based on ARM and Linux].

PubMed

Lu, Qiang; Li, Wenfeng; Zhang, Xixue; Li, Junmin; Liu, Longqing

2011-07-01

A acquisition module with ARM and Linux as a core was developed. This paper presents the hardware configuration and the software design. It is shown that the module can extract human lung sound reliably and effectively.

VIBRATING PERVAPORATION MODULES: EFFECT OF MODULE DESIGN ON PERFORMANCE

EPA Science Inventory

A third commercial-scale vibrating pervaporation membrane module was fabricated and evaluated for the separation of volatile organic compounds (VOCs) from aqueous solutions. Experiments with surrogate solutions of four hydrophobic VOCs (1,1,1-trichloroethane (TCA), trichloroethy...

Integrated modular teaching in dermatology for undergraduate students: A novel approach

PubMed Central

Karthikeyan, Kaliaperumal; Kumar, Annapurna

2014-01-01

Context: Undergraduate teaching in dermatology comprises didactic lectures and clinical classes. Integrated modular teaching is a novel approach, which integrates basic sciences with dermatology in the form of a module. Further the module also incorporates various teaching modalities, which facilitate active participation from students and promotes learning. The pre- and post-test values showed the effectiveness of the integrated module. The students feedback was encouraging. Aims: The aim of this study was to determine the acceptance and opinion of undergraduate students regarding integrated modular teaching as a new teaching aid in dermatology. Settings and Design: This was a descriptive study. Varied teaching methodologies involving multiple disciplines were undertaken in six major undergraduate topics in dermatology for seventh and eighth semester students. Materials and Methods: A total of six modules were conducted over a period of 12 months for students of seventh and eighth semesters. The topics for the various modules were sexually transmitted diseases, acquired immunodeficiency syndrome, oral ulcers, leprosy, connective tissue disorders and psoriasis. Faculty members from different disciplines participated. Pre- and post-test were conducted before and after the modules respectively to gauge the effectiveness of the modules. Results: It was found that almost every student had a better score on the posttest as compared to the pretest. General feedback obtained from the students showed that all of them felt that modular teaching was a more interesting and useful teaching learning experience than conventional teaching. Conclusions: Integrated modular teaching can be an effective adjunct in imparting theoretical and practical knowledge to the students. Further, various teaching methodologies can be used in integrated modules effectively with active student participation. Thus integrated modular teaching addresses two important issues in medical education, namely integration and active student participation. PMID:25165641

Integrated modular teaching in dermatology for undergraduate students: A novel approach.

PubMed

Karthikeyan, Kaliaperumal; Kumar, Annapurna

2014-07-01

Undergraduate teaching in dermatology comprises didactic lectures and clinical classes. Integrated modular teaching is a novel approach, which integrates basic sciences with dermatology in the form of a module. Further the module also incorporates various teaching modalities, which facilitate active participation from students and promotes learning. The pre- and post-test values showed the effectiveness of the integrated module. The students feedback was encouraging. The aim of this study was to determine the acceptance and opinion of undergraduate students regarding integrated modular teaching as a new teaching aid in dermatology. This was a descriptive study. Varied teaching methodologies involving multiple disciplines were undertaken in six major undergraduate topics in dermatology for seventh and eighth semester students. A total of six modules were conducted over a period of 12 months for students of seventh and eighth semesters. The topics for the various modules were sexually transmitted diseases, acquired immunodeficiency syndrome, oral ulcers, leprosy, connective tissue disorders and psoriasis. Faculty members from different disciplines participated. Pre- and post-test were conducted before and after the modules respectively to gauge the effectiveness of the modules. It was found that almost every student had a better score on the posttest as compared to the pretest. General feedback obtained from the students showed that all of them felt that modular teaching was a more interesting and useful teaching learning experience than conventional teaching. Integrated modular teaching can be an effective adjunct in imparting theoretical and practical knowledge to the students. Further, various teaching methodologies can be used in integrated modules effectively with active student participation. Thus integrated modular teaching addresses two important issues in medical education, namely integration and active student participation.

Effects of dopamine D1-like and D2-like antagonists on cocaine discrimination in muscarinic receptor knockout mice.

PubMed

Thomsen, Morgane; Caine, Simon Barak

2016-04-05

Muscarinic and dopamine brain systems interact intimately, and muscarinic receptor ligands, like dopamine ligands, can modulate the reinforcing and discriminative stimulus (S(D)) effects of cocaine. To enlighten the dopamine/muscarinic interactions as they pertain to the S(D) effects of cocaine, we evaluated whether muscarinic M1, M2 or M4 receptors are necessary for dopamine D1 and/or D2 antagonist mediated modulation of the S(D) effects of cocaine. Knockout mice lacking M1, M2, or M4 receptors, as well as control wild-type mice and outbred Swiss-Webster mice, were trained to discriminate 10mg/kg cocaine from saline in a food-reinforced drug discrimination procedure. Effects of pretreatments with the dopamine D1 antagonist SCH 23390 and the dopamine D2 antagonist eticlopride were evaluated. In intact mice, both SCH 23390 and eticlopride attenuated the cocaine discriminative stimulus effect, as expected. SCH 23390 similarly attenuated the cocaine discriminative stimulus effect in M1 knockout mice, but not in mice lacking M2 or M4 receptors. The effects of eticlopride were comparable in each knockout strain. These findings demonstrate differences in the way that D1 and D2 antagonists modulate the S(D) effects of cocaine, D1 modulation being at least partially dependent upon activity at the inhibitory M2/M4 muscarinic subtypes, while D2 modulation appeared independent of these systems. Copyright © 2016 Elsevier B.V. All rights reserved.

The Effects of Locus Coeruleus and Norepinephrine in Methamphetamine Toxicity

PubMed Central

Ferrucci, Michela; Giorgi, Filippo S; Bartalucci, Alessia; Busceti, Carla L; Fornai, Francesco

2013-01-01

The activity of locus coeruleus (LC) neurons has been extensively investigated in a variety of behavioural states. In fact this norepinephrine (NE)-containing nucleus modulates many physiological and pathological conditions including the sleep-waking cycle, movement disorders, mood alterations, convulsive seizures, and the effects of drugs such as psychostimulants and opioids. This review focuses on the modulation exerted by central NE pathways on the behavioural and neurotoxic effects produced by the psychostimulant methamphetamine, essentially the modulation of the activity of mesencephalic dopamine (DA) neurons. In fact, although NE in itself mediates some behavioural effects induced by methamphetamine, NE modulation of DA release is pivotal for methamphetamine-induced behavioural states and neurotoxicity. These interactions are discussed on the basis of the state of the art of the functional neuroanatomy of central NE- and DA systems. Emphasis is given to those brain sites possessing a remarkable overlapping of both neurotransmitters. PMID:23814540

Effectiveness of Discovery Learning-Based Transformation Geometry Module

NASA Astrophysics Data System (ADS)

Febriana, R.; Haryono, Y.; Yusri, R.

2017-09-01

Development of transformation geometry module is conducted because the students got difficulties to understand the existing book. The purpose of the research was to find out the effectiveness of discovery learning-based transformation geometry module toward student’s activity. Model of the development was Plomp model consisting preliminary research, prototyping phase and assessment phase. The research was focused on assessment phase where it was to observe the designed product effectiveness. The instrument was observation sheet. The observed activities were visual activities, oral activities, listening activities, mental activities, emotional activities and motor activities. Based on the result of the research, it is found that visual activities, learning activities, writing activities, the student’s activity is in the criteria very effective. It can be concluded that the use of discovery learning-based transformation geometry module use can increase the positive student’s activity and decrease the negative activity.

Stability Analysis and Internal Heating Effect on Oscillatory Convection in a Viscoelastic Fluid Saturated Porous Medium Under Gravity Modulation

NASA Astrophysics Data System (ADS)

Bhadauria, B. S.; Singh, M. K.; Singh, A.; Singh, B. K.; Kiran, P.

2016-12-01

In this paper, we investigate the combined effect of internal heating and time periodic gravity modulation in a viscoelastic fluid saturated porous medium by reducing the problem into a complex non-autonomous Ginzgburg-Landau equation. Weak nonlinear stability analysis has been performed by using power series expansion in terms of the amplitude of gravity modulation, which is assumed to be small. The Nusselt number is obtained in terms of the amplitude for oscillatory mode of convection. The influence of viscoelastic parameters on heat transfer has been discussed. Gravity modulation is found to have a destabilizing effect at low frequencies and a stabilizing effect at high frequencies. Finally, it is found that overstability advances the onset of convection, more with internal heating. The conditions for which the complex Ginzgburg-Landau equation undergoes Hopf bifurcation and the amplitude equation undergoes supercritical pitchfork bifurcation are studied.

Unstart coupling mechanism analysis of multiple-modules hypersonic inlet.

PubMed

Hu, Jichao; Chang, Juntao; Wang, Lei; Cao, Shibin; Bao, Wen

2013-01-01

The combination of multiplemodules in parallel manner is an important way to achieve the much higher thrust of scramjet engine. For the multiple-modules scramjet engine, when inlet unstarted oscillatory flow appears in a single-module engine due to high backpressure, how to interact with each module by massflow spillage, and whether inlet unstart occurs in other modules are important issues. The unstarted flowfield and coupling characteristic for a three-module hypersonic inlet caused by center module II and side module III were, conducted respectively. The results indicate that the other two hypersonic inlets are forced into unstarted flow when unstarted phenomenon appears on a single-module hypersonic inlet due to high backpressure, and the reversed flow in the isolator dominates the formation, expansion, shrinkage, and disappearance of the vortexes, and thus, it is the major factor of unstart coupling of multiple-modules hypersonic inlet. The coupling effect among multiple modules makes hypersonic inlet be more likely unstarted.

A deterministic guide for material and mode dependence of on-chip electro-optic modulator performance

NASA Astrophysics Data System (ADS)

Amin, Rubab; Suer, Can; Ma, Zhizhen; Sarpkaya, Ibrahim; Khurgin, Jacob B.; Agarwal, Ritesh; Sorger, Volker J.

2017-10-01

Electro-optic modulation is a key function in optical data communication and possible future optical computing engines. The performance of modulators intricately depends on the interaction between the actively modulated material and the propagating waveguide mode. While high-performing modulators were demonstrated before, the approaches were taken as ad-hoc. Here we show the first systematic investigation to incorporate a holistic analysis for high-performance and ultra-compact electro-optic modulators on-chip. We show that intricate interplay between active modulation material and optical mode plays a key role in the device operation. Based on physical tradeoffs such as index modulation, loss, optical confinement factors and slow-light effects, we find that bias-material-mode regions exist where high phase modulation and high loss (absorption) modulation is found. This work paves the way for a holistic design rule of electro-optic modulators for on-chip integration.

Frequency of gamma oscillations in humans is modulated by velocity of visual motion

PubMed Central

Butorina, Anna V.; Sysoeva, Olga V.; Prokofyev, Andrey O.; Nikolaeva, Anastasia Yu.; Stroganova, Tatiana A.

2015-01-01

Gamma oscillations are generated in networks of inhibitory fast-spiking (FS) parvalbumin-positive (PV) interneurons and pyramidal cells. In animals, gamma frequency is modulated by the velocity of visual motion; the effect of velocity has not been evaluated in humans. In this work, we have studied velocity-related modulations of gamma frequency in children using MEG/EEG. We also investigated whether such modulations predict the prominence of the “spatial suppression” effect (Tadin D, Lappin JS, Gilroy LA, Blake R. Nature 424: 312-315, 2003) that is thought to depend on cortical center-surround inhibitory mechanisms. MEG/EEG was recorded in 27 normal boys aged 8–15 yr while they watched high-contrast black-and-white annular gratings drifting with velocities of 1.2, 3.6, and 6.0°/s and performed a simple detection task. The spatial suppression effect was assessed in a separate psychophysical experiment. MEG gamma oscillation frequency increased while power decreased with increasing velocity of visual motion. In EEG, the effects were less reliable. The frequencies of the velocity-specific gamma peaks were 64.9, 74.8, and 87.1 Hz for the slow, medium, and fast motions, respectively. The frequency of the gamma response elicited during slow and medium velocity of visual motion decreased with subject age, whereas the range of gamma frequency modulation by velocity increased with age. The frequency modulation range predicted spatial suppression even after controlling for the effect of age. We suggest that the modulation of the MEG gamma frequency by velocity of visual motion reflects excitability of cortical inhibitory circuits and can be used to investigate their normal and pathological development in the human brain. PMID:25925324

Importance of envelope modulations during consonants and vowels in segmentally interrupted sentencesa)

PubMed Central

Fogerty, Daniel

2014-01-01

The present study investigated the importance of overall segment amplitude and intrinsic segment amplitude modulation of consonants and vowels to sentence intelligibility. Sentences were processed according to three conditions that replaced consonant or vowel segments with noise matched to the long-term average speech spectrum. Segments were replaced with (1) low-level noise that distorted the overall sentence envelope, (2) segment-level noise that restored the overall syllabic amplitude modulation of the sentence, and (3) segment-modulated noise that further restored faster temporal envelope modulations during the vowel. Results from the first experiment demonstrated an incremental benefit with increasing resolution of the vowel temporal envelope. However, amplitude modulations of replaced consonant segments had a comparatively minimal effect on overall sentence intelligibility scores. A second experiment selectively noise-masked preserved vowel segments in order to equate overall performance of consonant-replaced sentences to that of the vowel-replaced sentences. Results demonstrated no significant effect of restoring consonant modulations during the interrupting noise when existing vowel cues were degraded. A third experiment demonstrated greater perceived sentence continuity with the preservation or addition of vowel envelope modulations. Overall, results support previous investigations demonstrating the importance of vowel envelope modulations to the intelligibility of interrupted sentences. PMID:24606291

A design of optical modulation system with pixel-level modulation accuracy

NASA Astrophysics Data System (ADS)

Zheng, Shiwei; Qu, Xinghua; Feng, Wei; Liang, Baoqiu

2018-01-01

Vision measurement has been widely used in the field of dimensional measurement and surface metrology. However, traditional methods of vision measurement have many limits such as low dynamic range and poor reconfigurability. The optical modulation system before image formation has the advantage of high dynamic range, high accuracy and more flexibility, and the modulation accuracy is the key parameter which determines the accuracy and effectiveness of optical modulation system. In this paper, an optical modulation system with pixel level accuracy is designed and built based on multi-points reflective imaging theory and digital micromirror device (DMD). The system consisted of digital micromirror device, CCD camera and lens. Firstly we achieved accurate pixel-to-pixel correspondence between the DMD mirrors and the CCD pixels by moire fringe and an image processing of sampling and interpolation. Then we built three coordinate systems and calculated the mathematic relationship between the coordinate of digital micro-mirror and CCD pixels using a checkerboard pattern. A verification experiment proves that the correspondence error is less than 0.5 pixel. The results show that the modulation accuracy of system meets the requirements of modulation. Furthermore, the high reflecting edge of a metal circular piece can be detected using the system, which proves the effectiveness of the optical modulation system.

Developing online learning modules in a family medicine residency.

PubMed

Skye, Eric P; Wimsatt, Leslie A; Master-Hunter, Tara A; Locke, Amy B

2011-03-01

Online modules offer an opportunity to overcome barriers to educational delivery. Such approaches can require significant investment dependent on the development model used. There is little in the literature on the formative assessment of design and development. Better understanding is needed to determine effective methods of training and supporting faculty authors. The purpose of this study was to examine the effectiveness of Web-based modules developed by a Department of Family Medicine in delivering instruction to resident learners and to examine perceptions of the design and development process. Participants included 49 resident learners and 28 faculty and staff members as the development team. Data collection involved use of Web-based surveys, participant observation focus groups, and pretesting/posttesting. Frequency distributions and mean comparisons were used to analyze quantitative data. Participant comments were thematically analyzed. Residents felt that modules met their educational goals and contributed to understanding of core content. Pretest/posttest data showed statistical improvement for a majority of modules. The use of Web authoring software for Web-based learning and scheduling time to work on the modules posed the greatest challenges to module authors. Formative assessment methods can provide important information to module developers and support staff to shape training, content development, and improve module ease of use, navigation, and content for resident learners.

Value-modulated oculomotor capture by task-irrelevant stimuli is a consequence of early competition on the saccade map.

PubMed

Pearson, Daniel; Osborn, Raphaella; Whitford, Thomas J; Failing, Michel; Theeuwes, Jan; Le Pelley, Mike E

2016-10-01

Recent research has shown that reward learning can modulate oculomotor and attentional capture by physically salient and task-irrelevant distractor stimuli, even when directing gaze to those stimuli is directly counterproductive to receiving reward. This value-modulated oculomotor capture effect may reflect biased competition in the oculomotor system, such that the relationship between a stimulus feature and reward enhances that feature's representation on an internal priority map. However, it is also possible that this effect is a result of reward reducing the threshold for a saccade to be made to salient items. Here, we demonstrate value-modulated oculomotor capture when two reward-associated distractor stimuli are presented simultaneously in the same search display. The influence of reward on oculomotor capture is found to be most prominent at the shortest saccade latencies. We conclude that the value-modulated oculomotor capture effect is a consequence of biased competition on the saccade priority map and cannot be explained by a general reduction in saccadic threshold.

Nonadiabatic effect on the quantum heat flux control.

PubMed

Uchiyama, Chikako

2014-05-01

We provide a general formula of quantum transfer that includes the nonadiabatic effect under periodic environmental modulation by using full counting statistics in Hilbert-Schmidt space. Applying the formula to an anharmonic junction model that interacts with two bosonic environments within the Markovian approximation, we find that the quantum transfer is divided into the adiabatic (dynamical and geometrical phases) and nonadiabatic contributions. This extension shows the dependence of quantum transfer on the initial condition of the anharmonic junction just before the modulation, as well as the characteristic environmental parameters such as interaction strength and cut-off frequency of spectral density. We show that the nonadiabatic contribution represents the reminiscent effect of past modulation including the transition from the initial condition of the anharmonic junction to a steady state determined by the very beginning of the modulation. This enables us to tune the frequency range of modulation, whereby we can obtain the quantum flux corresponding to the geometrical phase by setting the initial condition of the anharmonic junction.

Combining module based on coherent polarization beam combining.

PubMed

Yang, Yan; Geng, Chao; Li, Feng; Li, Xinyang

2017-03-01

A multiaperture receiver with a phased array is an effective approach to overcome the effect of the random optical disturbance in coherent free-space laser communications, in which one of the key technologies is how to efficiently combine the multiple laser beams received by the phased array antenna. A combining module based on coherent polarization beam combining (CPBC), which can combine multiple laser beams to one laser beam with high combining efficiency and output a linearly polarized beam, is proposed in this paper. The principle of the combining module is introduced, the coherent polarization combining efficiency of CPBC is analyzed, and the performance of the combining module is evaluated. Moreover, the feasibility and the expansibility of the proposed combining module are validated in experiments of CPBC based on active phase-locking.

[Research and development of portable hypertension therapeutic apparatus based on biofeedback mechanism].

PubMed

Huang, Rong; He, Hongmei; Pi, Xitian; Diao, Ziji; Zhao, Suwen

2014-06-01

Non-drug treatment of hypertension has become a research hotspot, which might overcome the heavy economic burden and side effects of drug treatment for the patients. Because of the good treatment effect and convenient operation, a new treatment based on slow breathing training is increasingly becoming a kind of physical therapy for hypertension. This paper explains the principle of hypertension treatment based on slow breathing training method, and introduces the overall structure of the portable blood pressure controlling instrument, including breathing detection circuit, the core control module, audio module, memory module and man-machine interaction module. We give a brief introduction to the instrument and the software in this paper. The prototype testing results showed that the treatment had a significant effect on controlling the blood pressure.

Research on Potential Induced Degradation (PID) of PV Modules in Different Typical Climate Regions

NASA Astrophysics Data System (ADS)

Daoren, Gong; Yingnan, Chen; Gang, Sun; Wenjing, Wang; Zhenshuang, Ji

2018-03-01

Potential Induced Degradation (PID) is one of the most important factors effecting the performances of Photovoltaic (PV) modules and PV systems in recent years. In this paper the PID phenomena of the PV power plant in different typical climate regions were studied and some experimental PID simulations were carried out in order to find out the factors effecting the performance by PID. The results show that the typical PID phenomena are easy to occur in cells close to the border of the PV module. PID phenomena can appear in PV power plants under different climate conditions, but the effecting degrees on module performance are different depending on temperature, humidity and other parameters. We also find the maximum power would recover in some degree after positive-bias voltage duration.

RECOVERY OF LARGE ANGULAR SCALE CMB POLARIZATION FOR INSTRUMENTS EMPLOYING VARIABLE-DELAY POLARIZATION MODULATORS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, N. J.; Marriage, T. A.; Appel, J. W.

2016-02-20

Variable-delay Polarization Modulators (VPMs) are currently being implemented in experiments designed to measure the polarization of the cosmic microwave background on large angular scales because of their capability for providing rapid, front-end polarization modulation and control over systematic errors. Despite the advantages provided by the VPM, it is important to identify and mitigate any time-varying effects that leak into the synchronously modulated component of the signal. In this paper, the effect of emission from a 300 K VPM on the system performance is considered and addressed. Though instrument design can greatly reduce the influence of modulated VPM emission, some residualmore » modulated signal is expected. VPM emission is treated in the presence of rotational misalignments and temperature variation. Simulations of time-ordered data are used to evaluate the effect of these residual errors on the power spectrum. The analysis and modeling in this paper guides experimentalists on the critical aspects of observations using VPMs as front-end modulators. By implementing the characterizations and controls as described, front-end VPM modulation can be very powerful for mitigating 1/f noise in large angular scale polarimetric surveys. None of the systematic errors studied fundamentally limit the detection and characterization of B-modes on large scales for a tensor-to-scalar ratio of r = 0.01. Indeed, r < 0.01 is achievable with commensurately improved characterizations and controls.« less

Gonadal hormone modulation of Δ9-tetrahydrocannabinol-induced antinociception and metabolism in female versus male rats

PubMed Central

Craft, R.M.; Haas, A.E.; Wiley, J.L.; Yu, Z.; Clowers, B.H.

2016-01-01

The gonadal hormones testosterone (T) in adult males and estradiol (E2) in adult females have been reported to modulate behavioral effects of Δ9-tetrahydrocannabinol (THC). This study determined whether activational effects of T and E2 are sex-specific, and whether hormones modulate production of the active metabolite 11-hydroxy-THC (11-OH-THC) and the inactive metabolite 11-nor-9-carboxy-THC (THC-COOH). Adult male and female rats were gonadectomized (GDX) and treated with nothing (0), T (10-mm Silastic capsule/100 g body weight), or E2 (1-mm Silastic capsule/rat). Three weeks later, saline or the cytochrome P450 inhibitor proadifen (25 mg/kg; to block THC metabolism and boost THC's effects) was injected i.p.; one h later, vehicle or THC (3 mg/kg females, 5 mg/kg males) was injected i.p., and rats were tested for antinociceptive and motoric effects 15-240 min post-injection. T did not consistently alter THC-induced antinociception in males, but decreased it in females (tail withdrawal test). Conversely, T decreased THC-induced catalepsy in males, but had no effect in females. E2 did not alter THC-induced antinociception in females, but enhanced it in males. The discrepant effects of T and E2 on males’ and females’ behavioral responses to THC suggests that sexual differentiation of THC sensitivity is not simply due to activational effects of hormones, but also occurs via organizational hormone or sex chromosome effects. Analysis of serum showed that proadifen increased THC levels, E2 increased 11-OH-THC in GDX males, and T decreased 11-OH-THC (and to a lesser extent, THC) in GDX females. Thus, hormone modulation of THC's behavioral effects is caused in part by hormone modulation of THC oxidation to its active metabolite. However, the fact that hormone modulation of metabolism did not alter THC sensitivity similarly on all behavioral measures within each sex suggests that other mechanisms also play a role in gonadal hormone modulation of THC sensitivity in adult rats. PMID:27670094

Development of Scientific Approach Based on Discovery Learning Module

NASA Astrophysics Data System (ADS)

Ellizar, E.; Hardeli, H.; Beltris, S.; Suharni, R.

2018-04-01

Scientific Approach is a learning process, designed to make the students actively construct their own knowledge through stages of scientific method. The scientific approach in learning process can be done by using learning modules. One of the learning model is discovery based learning. Discovery learning is a learning model for the valuable things in learning through various activities, such as observation, experience, and reasoning. In fact, the students’ activity to construct their own knowledge were not optimal. It’s because the available learning modules were not in line with the scientific approach. The purpose of this study was to develop a scientific approach discovery based learning module on Acid Based, also on electrolyte and non-electrolyte solution. The developing process of this chemistry modules use the Plomp Model with three main stages. The stages are preliminary research, prototyping stage, and the assessment stage. The subject of this research was the 10th and 11th Grade of Senior High School students (SMAN 2 Padang). Validation were tested by the experts of Chemistry lecturers and teachers. Practicality of these modules had been tested through questionnaire. The effectiveness had been tested through experimental procedure by comparing student achievement between experiment and control groups. Based on the findings, it can be concluded that the developed scientific approach discovery based learning module significantly improve the students’ learning in Acid-based and Electrolyte solution. The result of the data analysis indicated that the chemistry module was valid in content, construct, and presentation. Chemistry module also has a good practicality level and also accordance with the available time. This chemistry module was also effective, because it can help the students to understand the content of the learning material. That’s proved by the result of learning student. Based on the result can conclude that chemistry module based on discovery learning and scientific approach in electrolyte and non-electrolyte solution and Acid Based for the 10th and 11th grade of senior high school students were valid, practice, and effective.

Sensitivity of human auditory cortex to rapid frequency modulation revealed by multivariate representational similarity analysis.

PubMed

Joanisse, Marc F; DeSouza, Diedre D

2014-01-01

Functional Magnetic Resonance Imaging (fMRI) was used to investigate the extent, magnitude, and pattern of brain activity in response to rapid frequency-modulated sounds. We examined this by manipulating the direction (rise vs. fall) and the rate (fast vs. slow) of the apparent pitch of iterated rippled noise (IRN) bursts. Acoustic parameters were selected to capture features used in phoneme contrasts, however the stimuli themselves were not perceived as speech per se. Participants were scanned as they passively listened to sounds in an event-related paradigm. Univariate analyses revealed a greater level and extent of activation in bilateral auditory cortex in response to frequency-modulated sweeps compared to steady-state sounds. This effect was stronger in the left hemisphere. However, no regions showed selectivity for either rate or direction of frequency modulation. In contrast, multivoxel pattern analysis (MVPA) revealed feature-specific encoding for direction of modulation in auditory cortex bilaterally. Moreover, this effect was strongest when analyses were restricted to anatomical regions lying outside Heschl's gyrus. We found no support for feature-specific encoding of frequency modulation rate. Differential findings of modulation rate and direction of modulation are discussed with respect to their relevance to phonetic discrimination.

Characteristics of 5M modulated martensite in Ni-Mn-Ga magnetic shape memory alloys

NASA Astrophysics Data System (ADS)

Ćakır, A.; Acet, M.; Righi, L.; Albertini, F.; Farle, M.

2015-09-01

The applicability of the magnetic shape memory effect in Ni-Mn-based martensitic Heusler alloys is closely related to the nature of the crystallographically modulated martensite phase in these materials. We study the properties of modulated phases as a function of temperature and composition in three magnetic shape memory alloys Ni49.8Mn25.0Ga25.2, Ni49.8Mn27.1Ga23.1 and Ni49.5Mn28.6Ga21.9. The effect of substituting Ga for Mn leads to an anisotropic expansion of the lattice, where the b-parameter of the 5M modulated structure increases and the a and c-parameters decrease with increasing Ga concentration. The modulation vector is found to be both temperature and composition dependent. The size of the modulation vector corresponds to an incommensurate structure for Ni49.8Mn25.0Ga25.2 at all temperatures. For the other samples the modulation is incommensurate at low temperatures but reaches a commensurate value of q ≈ 0.400 close to room temperature. The results show that commensurateness of the 5M modulated structure is a special case of incommensurate 5M at a particular temperature.

Entropy-based divergent and convergent modular pattern reveals additive and synergistic anticerebral ischemia mechanisms.

PubMed

Yu, Yanan; Zhang, Xiaoxu; Li, Bing; Zhang, Yingying; Liu, Jun; Li, Haixia; Chen, Yinying; Wang, Pengqian; Kang, Ruixia; Wu, Hongli; Wang, Zhong

2016-12-01

Module-based network analysis of diverse pharmacological mechanisms is critical to systematically understand combination therapies and disease outcomes. We first constructed drug-target ischemic networks in baicalin, jasminoidin, ursodeoxycholic acid, and their combinations baicalin and jasminoidin as well as jasminoidin and ursodeoxycholic acid groups and identified modules using the entropy-based clustering algorithm. The modules 11, 7, 4, 8 and 3 were identified as baicalin, jasminoidin, ursodeoxycholic acid, baicalin and jasminoidin and jasminoidin and ursodeoxycholic acid-emerged responsive modules, while 12, 8, 15, 17 and 9 were identified as disappeared responsive modules based on variation of topological similarity, respectively. No overlapping differential biological processes were enriched between baicalin and jasminoidin and jasminoidin and ursodeoxycholic acid pure emerged responsive modules, but two were enriched by their co-disappeared responsive modules including nucleotide-excision repair and epithelial structure maintenance. We found an additive effect of baicalin and jasminoidin in a divergent pattern and a synergistic effect of jasminoidin and ursodeoxycholic acid in a convergent pattern on "central hit strategy" of regulating inflammation against cerebral ischemia. The proposed module-based approach may provide us a holistic view to understand multiple pharmacological mechanisms associated with differential phenotypes from the standpoint of modular pharmacology.

Scatter correction for x-ray conebeam CT using one-dimensional primary modulation

NASA Astrophysics Data System (ADS)

Zhu, Lei; Gao, Hewei; Bennett, N. Robert; Xing, Lei; Fahrig, Rebecca

2009-02-01

Recently, we developed an efficient scatter correction method for x-ray imaging using primary modulation. A two-dimensional (2D) primary modulator with spatially variant attenuating materials is inserted between the x-ray source and the object to separate primary and scatter signals in the Fourier domain. Due to the high modulation frequency in both directions, the 2D primary modulator has a strong scatter correction capability for objects with arbitrary geometries. However, signal processing on the modulated projection data requires knowledge of the modulator position and attenuation. In practical systems, mainly due to system gantry vibration, beam hardening effects and the ramp-filtering in the reconstruction, the insertion of the 2D primary modulator results in artifacts such as rings in the CT images, if no post-processing is applied. In this work, we eliminate the source of artifacts in the primary modulation method by using a one-dimensional (1D) modulator. The modulator is aligned parallel to the ramp-filtering direction to avoid error magnification, while sufficient primary modulation is still achieved for scatter correction on a quasicylindrical object, such as a human body. The scatter correction algorithm is also greatly simplified for the convenience and stability in practical implementations. The method is evaluated on a clinical CBCT system using the Catphan© 600 phantom. The result shows effective scatter suppression without introducing additional artifacts. In the selected regions of interest, the reconstruction error is reduced from 187.2HU to 10.0HU if the proposed method is used.

[Research of dual-photoelastic-modulator-based beat frequency modulation and Fourier-Bessel transform imaging spectrometer].

PubMed

Wang, Zhi-Bin; Zhang, Rui; Wang, Yao-Li; Huang, Yan-Fei; Chen, You-Hua; Wang, Li-Fu; Yang, Qiang

2014-02-01

As the existing photoelastic-modulator(PEM) modulating frequency in the tens of kHz to hundreds of kHz between, leading to frequency of modulated interference signal is higher, so ordinary array detector cannot effectively caprure interference signal..A new beat frequency modulation method based on dual-photoelastic-modulator (Dual-PEM) and Fourier-Bessel transform is proposed as an key component of dual-photoelastic-modulator-based imaging spectrometer (Dual-PEM-IS) combined with charge coupled device (CCD). The dual-PEM are operated as an electro-optic circular retardance modulator, Operating the PEMs at slightly different resonant frequencies w1 and w2 respectively, generates a differential signal at a much lower heterodyne frequency that modulates the incident light. This method not only retains the advantages of the existing PEM, but also the frequency of modulated photocurrent decreased by 2-3 orders of magnitude (10-500 Hz) and can be detected by common array detector, and the incident light spectra can be obtained by Fourier-Bessel transform of low frequency component in the modulated signal. The method makes the PEM has the dual capability of imaging and spectral measurement. The basic principle is introduced, the basic equations is derived, and the feasibility is verified through the corresponding numerical simulation and experiment. This method has' potential applications in imaging spectrometer technology, and analysis of the effect of deviation of the optical path difference. This work provides the necessary theoretical basis for remote sensing of new Dual-PEM-IS and for engineering implementation of spectra inversion.

An online learning module focused on smoking education and prevention for college students: implications for college health instructors and allied health professionals.

PubMed

D'Abundo, Michelle Lee; Marinaro, Laura Marie; Fiala, Kelly Ann

2010-01-01

The purpose of this research was to pilot-test the effectiveness of an online learning module focused on smoking for an undergraduate general education fitness and wellness course. Students enrolled in a required fitness and wellness course were given the opportunity to participate. Participants (n = 510) completed a brief demographic questionnaire and a 10-question pretest about the effects of smoking before viewing a 15-minute presentation about the effects of smoking and completing the same 10 questions as a post-test. Repeated measures ANOVAs were conducted to evaluate knowledge gains. An overall time effect was observed (pretest score 4.9 +/- 1.3, post-test score 7.2 +/- 2.1). Significantly greater knowledge gains were found in nonsmokers (2.1 +/- 2.2) than in smokers (1.1 +/- 2.2). Females (2.3 +/- 2.3) had significantly greater knowledge gains than males (1.5 +/- 2.2). Evidence supporting the effectiveness of the online learning module included significant knowledge gains for both smokers and nonsmokers, and the participants who smoked agreed the online learning module encouraged them to quit. In this research, students were also grouped by major (health-related majors vs non-health-related). There were 118 health-related majors in the sample, with 110 of those students completing the entire learning module. In this research, a learning module for college students was developed, but practical applications are provided not only for college health instructors but also for allied health professionals.

Unique effect of 4-hydroxyestradiol and its methylation metabolites on lipid and cholesterol profiles in ovariectomized female rats.

PubMed

Wang, Pan; Zhu, Bao-Ting

2017-04-05

Animal studies have shown that endogenous estrogens such as 17β-estradiol (E 2 ) can modulate lipid profiles in vivo, and this effect is generally thought to be mediated by the estrogen receptors (ERs). The present study sought to test a hypothesis that some of the endogenous estrogen metabolites that have very weak estrogenic activity may exert some of their modulating effects on lipid metabolism in an ER-independent manner. Using ovariectomized female rats as an in vivo model, we found that 4-hydroxyestradiol (4-OH-E 2 ) has a markedly stronger effect in reducing the adipocyte size and serum cholesterol level in rats compared to E 2 , despite the weaker estrogenic activity of 4-OH-E 2 . Moreover, when E 2 or 4-OH-E 2 is used in combination with ICI-182,780 (an ER antagonist), some of their lipid-modulating effects are not blocked by this antiestrogen. Interestingly, two of the O-methylation metabolites of 4-OH-E 2 , namely, 4-methoxyestradiol and 4-methoxyestrone, which have much weaker estrogenic activity, were also found to have similar lipid-modulating effects compared to 4-OH-E 2 . Mechanistically, up-regulation of the expression of leptin, cytochrome P450 7A1 and LXRα genes is observed in the liver of animals treated with E 2 or 4-OH-E 2 , and the up-regulation is essentially not inhibited by co-treatment with ICI-182,780. These results demonstrate that some of the endogenous E 2 metabolites are functionally important modulators of lipid metabolic profiles in vivo. In addition, our findings indicate that an ER-independent pathway likely mediates some of the lipid-modulating effects of endogenous estrogens and their metabolic derivatives. Copyright © 2017 Elsevier B.V. All rights reserved.

A Feedback Model of Attention Explains the Diverse Effects of Attention on Neural Firing Rates and Receptive Field Structure.

PubMed

Miconi, Thomas; VanRullen, Rufin

2016-02-01

Visual attention has many effects on neural responses, producing complex changes in firing rates, as well as modifying the structure and size of receptive fields, both in topological and feature space. Several existing models of attention suggest that these effects arise from selective modulation of neural inputs. However, anatomical and physiological observations suggest that attentional modulation targets higher levels of the visual system (such as V4 or MT) rather than input areas (such as V1). Here we propose a simple mechanism that explains how a top-down attentional modulation, falling on higher visual areas, can produce the observed effects of attention on neural responses. Our model requires only the existence of modulatory feedback connections between areas, and short-range lateral inhibition within each area. Feedback connections redistribute the top-down modulation to lower areas, which in turn alters the inputs of other higher-area cells, including those that did not receive the initial modulation. This produces firing rate modulations and receptive field shifts. Simultaneously, short-range lateral inhibition between neighboring cells produce competitive effects that are automatically scaled to receptive field size in any given area. Our model reproduces the observed attentional effects on response rates (response gain, input gain, biased competition automatically scaled to receptive field size) and receptive field structure (shifts and resizing of receptive fields both spatially and in complex feature space), without modifying model parameters. Our model also makes the novel prediction that attentional effects on response curves should shift from response gain to contrast gain as the spatial focus of attention drifts away from the studied cell.

Field-effect modulation of the thermoelectric characteristics of silicon nanowires on plastic substrates.

PubMed

Choi, Jinyong; Jeon, Youngin; Cho, Kyoungah; Kim, Sangsig

2016-12-02

In this study, we demonstrate the substantial enhancement of the thermoelectric power factors of silicon nanowires (SiNWs) on plastic substrates achievable by field-effect modulation. The Seebeck coefficient and electrical conductivity are adjusted by varying the charge carrier concentration via electrical modulation with a gate voltage in the 0 to ±5 range, thus enhancing the power factors from 2.08 to 935 μW K -2 m -1 ) for n-type SiNWs, and from 453 to 944 μW K -2 m -1 ) for p-type SiNWs. The electrically modulated thermoelectric characteristics of SiNWs are analyzed and discussed.

Ultimate linewidth reduction of a semiconductor laser frequency-stabilized to a Fabry-Pérot interferometer.

PubMed

Bahoura, Messaoud; Clairon, André

2003-11-01

We report a theoretical dynamical analysis on effect of semiconductor laser phase noise on the achievable linewidth when locked to a Fabry-Pérot cavity fringe using a modulation-demodulation frequency stabilization technique such as the commonly used Pound-Drever-Hall frequency locking scheme. We show that, in the optical domain, the modulation-demodulation operation produces, in the presence of semiconductor laser phase noise, two kinds of excess noise, which could be much above the shot noise limit, namely, conversion noise (PM-to-AM) and intermodulation noise. We show that, in typical stabilization conditions, the ultimate semiconductor laser linewidth reduction can be severely limited by the intermodulation excess noise. The modulation-demodulation operation produces the undesirable nonlinear intermodulation effect through which the phase noise spectral components of the semiconductor laser, in the vicinity of even multiples of the modulation frequency, are downconverted into the bandpass of the frequency control loop. This adds a spurious signal, at the modulation frequency, to the error signal and limits the performance of the locked semiconductor laser. This effect, reported initially in the microwave domain using the quasistatic approximation, can be considerably reduced by a convenient choice of the modulation frequency.

Amplitude modulation detection by human listeners in reverberant sound fields: Carrier bandwidth effects and binaural versus monaural comparison.

PubMed

Zahorik, Pavel; Kim, Duck O; Kuwada, Shigeyuki; Anderson, Paul W; Brandewie, Eugene; Collecchia, Regina; Srinivasan, Nirmal

2012-06-01

Previous work [Zahorik et al., POMA, 12, 050005 (2011)] has reported that for a broadband noise carrier signal in a simulated reverberant sound field, human sensitivity to amplitude modulation (AM) is higher than would be predicted based on the broadband acoustical modulation transfer function (MTF) of the listening environment. Interpretation of this result was complicated by the fact that acoustical MTFs of rooms are often quite different for different carrier frequency regions, and listeners may have selectively responded to advantageous carrier frequency regions where the effective acoustic modulation loss due to the room was less than indicated by a broadband acoustic MTF analysis. Here, AM sensitivity testing and acoustic MTF analyses were expanded to include narrowband noise carriers (1-octave and 1/3-octave bands centered at 4 kHz), as well as monaural and binaural listening conditions. Narrowband results were found to be consistent with broadband results: In a reverberant sound field, human AM sensitivity is higher than indicated by the acoustical MTFs. The effect was greatest for modulation frequencies above 32 Hz and was present whether the stimulation was monaural or binaural. These results are suggestive of mechanisms that functionally enhance modulation in reverberant listening.

Optical modulation techniques for analog signal processing and CMOS compatible electro-optic modulation

NASA Astrophysics Data System (ADS)

Gill, Douglas M.; Rasras, Mahmoud; Tu, Kun-Yii; Chen, Young-Kai; White, Alice E.; Patel, Sanjay S.; Carothers, Daniel; Pomerene, Andrew; Kamocsai, Robert; Beattie, James; Kopa, Anthony; Apsel, Alyssa; Beals, Mark; Mitchel, Jurgen; Liu, Jifeng; Kimerling, Lionel C.

2008-02-01

Integrating electronic and photonic functions onto a single silicon-based chip using techniques compatible with mass-production CMOS electronics will enable new design paradigms for existing system architectures and open new opportunities for electro-optic applications with the potential to dramatically change the management, cost, footprint, weight, and power consumption of today's communication systems. While broadband analog system applications represent a smaller volume market than that for digital data transmission, there are significant deployments of analog electro-optic systems for commercial and military applications. Broadband linear modulation is a critical building block in optical analog signal processing and also could have significant applications in digital communication systems. Recently, broadband electro-optic modulators on a silicon platform have been demonstrated based on the plasma dispersion effect. The use of the plasma dispersion effect within a CMOS compatible waveguide creates new challenges and opportunities for analog signal processing since the index and propagation loss change within the waveguide during modulation. We will review the current status of silicon-based electrooptic modulators and also linearization techniques for optical modulation.

On compensation of four wave mixing effect in dispersion managed hybrid WDM-OTDM multicast overlay system with optical phase conjugation modules

NASA Astrophysics Data System (ADS)

Singh, Sukhbir; Singh, Surinder

2017-11-01

This paper investigated the effect of FWM and its suppression using optical phase conjugation modules in dispersion managed hybrid WDM-OTDM multicast overlay system. Interaction between propagating wavelength signals at higher power level causes new FWM component generation that can significant limit the system performance. OPC module consists of the pump signal and 0.6 km HNLF implemented in midway of optical link to generate destructive phase FWM components. Investigation revealed that by use of even OPC module in optical link reduces the FWM power and mitigate the interaction between wavelength signals at variable signal input power, dispersion parameter (β2) and transmission distance. System performance comparison is also made between without DM-OPC module, with DM and with DM-OPC module in scenario of FWM tolerance. The BER performance of hybrid WDM-OTDM multicast system using OPC module is improved by multiplication factor of 2 as comparable to dispersion managed and coverage distance is increased by factor of 2 as in Singh and Singh (2016).

Monthly modulation in dark matter direct-detection experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Britto, Vivian; Meyers, Joel, E-mail: vivian.britto@mail.utoronto.ca, E-mail: jmeyers@cita.utoronto.ca

2015-11-01

The signals in dark matter direct-detection experiments should exhibit modulation signatures due to the Earth's motion with respect to the Galactic dark matter halo. The annual and daily modulations, due to the Earth's revolution about the Sun and rotation about its own axis, have been explored previously. Monthly modulation is another such feature present in direct detection signals, and provides a nearly model-independent method of distinguishing dark matter signal events from background. We study here monthly modulations in detail for both WIMP and WISP dark matter searches, examining both the effect of the motion of the Earth about the Earth-Moonmore » barycenter and the gravitational focusing due to the Moon. For WIMP searches, we calculate the monthly modulation of the count rate and show the effects are too small to be observed in the foreseeable future. For WISP dark matter experiments, we show that the photons generated by WISP to photon conversion have frequencies which undergo a monthly modulating shift which is detectable with current technology and which cannot in general be neglected in high resolution WISP searches.« less

Strong-coupling induced damping of spin-echo modulations in magic-angle-spinning NMR: Implications for J coupling measurements in disordered solids

NASA Astrophysics Data System (ADS)

Guerry, Paul; Brown, Steven P.; Smith, Mark E.

2017-10-01

In the context of improving J coupling measurements in disordered solids, strong coupling effects have been investigated in the spin-echo and refocused INADEQUATE spin-echo (REINE) modulations of three- and four-spin systems under magic-angle-spinning (MAS), using density matrix simulations and solid-state NMR experiments on a cadmium phosphate glass. Analytical models are developed for the different modulation regimes, which are shown to be distinguishable in practice using Akaike's information criterion. REINE modulations are shown to be free of the damping that occurs for spin-echo modulations when the observed spin has the same isotropic chemical shift as its neighbour. Damping also occurs when the observed spin is bonded to a strongly-coupled pair. For mid-chain units, the presence of both direct and relayed damping makes both REINE and spin-echo modulations impossible to interpret quantitatively. We nonetheless outline how a qualitative comparison of the modulation curves can provide valuable information on disordered networks, possibly also pertaining to dynamic effects therein.

Effect of fluorescent particle size on the modulation efficiency of ultrasound-modulated fluorescence.

PubMed

Liu, Yuan; Yuan, Baohong; Vignola, Joseph

2012-01-01

To investigate whether the size of fluorescent particles affects the modulation efficiency of ultrasound-modulated fluorescence (UMF), we measured UMF and DC (direct current) signals of the fluorescence emission from four different sized fluorescent particles: (1) three carboxylate-modified fluorescent microspheres (FM) with diameters of 20 nm, 200 nm, and 1.0 µm and (2) streptavidin-conjugated Alexa Fluor 647 with a diameter of approximately 5 nm. The UMF and DC signals were simultaneously measured using a broadband lock-in amplifier and a narrowband amplifier, respectively. The ratio of the UMF strength to the DC signal strength is defined as the modulation efficiency. This modulation efficiency was then used to evaluate the effects of fluorophore size and concentration. Results show that the modulation efficiency was improved by approximately a factor of two when the size of the fluorescent particles is increased from 5 nm to 1 µm. In addition, the linear relationship between the UMF strength and ultrasound pressure (observed in our previous study) were maintained regardless of the fluorescent particle sizes.

Effect of fluorescent particle size on the modulation efficiency of ultrasound-modulated fluorescence

PubMed Central

Liu, Yuan; Yuan, Baohong; Vignola, Joseph

2013-01-01

To investigate whether the size of fluorescent particles affects the modulation efficiency of ultrasound-modulated fluorescence (UMF), we measured UMF and DC (direct current) signals of the fluorescence emission from four different sized fluorescent particles: (1) three carboxylate-modified fluorescent microspheres (FM) with diameters of 20 nm, 200 nm, and 1.0 µm and (2) streptavidin-conjugated Alexa Fluor 647 with a diameter of approximately 5 nm. The UMF and DC signals were simultaneously measured using a broadband lock-in amplifier and a narrowband amplifier, respectively. The ratio of the UMF strength to the DC signal strength is defined as the modulation efficiency. This modulation efficiency was then used to evaluate the effects of fluorophore size and concentration. Results show that the modulation efficiency was improved by approximately a factor of two when the size of the fluorescent particles is increased from 5 nm to 1 µm. In addition, the linear relationship between the UMF strength and ultrasound pressure (observed in our previous study) were maintained regardless of the fluorescent particle sizes. PMID:24179476

Effective or just practical? An evaluation of an online postgraduate module on evidence-based medicine (EBM)

PubMed Central

2013-01-01

Background Teaching the steps of evidence-based medicine (EBM) to undergraduate as well as postgraduate health care professionals is crucial for implementation of effective, beneficial health care practices and abandonment of ineffective, harmful ones. Stellenbosch University in Cape Town, South Africa, offers a 12-week, completely online module on EBM within the Family Medicine division, to medical specialists in their first year of training. The aim of this study was to formatively evaluate this module; assessing both the mode of delivery; as well as the perceived effectiveness and usefulness thereof. Methods We used mixed methods to evaluate this module: A document review to assess whether the content of the module reflects important EBM competencies; a survey of the students to determine their experiences of the module; and semi-structured interviews with the tutors to explore their perspectives of the module. Ethics approval was obtained. Results The document review indicated that EBM competencies were covered adequately, although critical appraisal only focused on randomised controlled trials and guidelines. Students had a positive attitude towards the module, but felt that they needed more support from the tutors. Tutors felt that students engaged actively in discussions, but experienced difficulties with understanding certain concepts of EBM. Furthermore, they felt that it was challenging explaining these via the online learning platform and saw the need to incorporate more advanced technology to better connect with the students. In their view the key to successful learning of EBM was to keep it relevant and applicable to everyday practice. Tutors also felt that an online module on EBM was advantageous, since doctors from all over the world were able to participate. Conclusion Our study has shown that the online module on EBM was effective in increasing EBM knowledge and skills of postgraduate students and was well received by both students and tutors. Students and tutors experienced generic challenges that accompany any educational intervention of EBM (e.g. understanding difficult concepts), but in addition had to deal with challenges unique to the online learning environment. Teachers of EBM should acknowledge these so as to enhance and successfully implement EBM teaching and learning for all students. PMID:23710548

Method to determine the true modulation ratio for comprehensive two-dimensional gas chromatography.

PubMed

Pinkerton, David K; Parsons, Brendon A; Synovec, Robert E

2016-12-09

A new method is presented to determine the true modulation ratio, M R , from the measurable effective modulation ratio, M R *, in comprehensive two-dimensional gas chromatography, GC×GC, without the requirement for a detector at the end of the primary column. The method was developed through the investigation of modulator induced band broadening, as a function of 1 W b and the selected modulation period, P M , for simulated GC×GC data, by first defining primary column 1 D peak(s) and simulating the modulation process. Gaussian curve fitting is used to model each modulated secondary column separation peaklet, 2 D, in the unfolded GC×GC data to accurately determine the maxima of the peaklet distribution, followed by Gaussian curve fitting to the maxima to determine the effective 1 D peak profile and width, 1 W b *. The relationship between 1 W b and 1 W b * is studied as a function of the effective modulation ratio, M R *, which is 1 W b * divided by P M , in order to determine the true modulation ratio, M R , which is 1 W b divided by P M . We explore how peak sampling phase (in-phase and out-of-phase) plays a role in the relationship between M R and M R *. Experimental validation of the simulated results is also provided, to span a range of commonly implemented conditions with typical 1 W b (2-4.5s) and P M (0.25-8s). Use of M R <2 significantly broadens the 1 D peak (M R *≥1.2M R ) corresponding to a loss in 1 D peak capacity, 1 n c ≥20%. The new method relies upon mapping from M R * to M R , which is discussed in relation to peak capacity theories for GC×GC. It is found that optimizing 1 n c in GC×GC requires that 1 W b is minimized and must be sampled with a sufficiently short P M (1-2s) to minimize modulator induced band broadening and a subsequent reduction in the effective 1 D peak capacity. Copyright © 2016 Elsevier B.V. All rights reserved.

Effective or just practical? An evaluation of an online postgraduate module on evidence-based medicine (EBM).

PubMed

Rohwer, Anke; Young, Taryn; van Schalkwyk, Susan

2013-05-27

Teaching the steps of evidence-based medicine (EBM) to undergraduate as well as postgraduate health care professionals is crucial for implementation of effective, beneficial health care practices and abandonment of ineffective, harmful ones. Stellenbosch University in Cape Town, South Africa, offers a 12-week, completely online module on EBM within the Family Medicine division, to medical specialists in their first year of training. The aim of this study was to formatively evaluate this module; assessing both the mode of delivery; as well as the perceived effectiveness and usefulness thereof. We used mixed methods to evaluate this module: A document review to assess whether the content of the module reflects important EBM competencies; a survey of the students to determine their experiences of the module; and semi-structured interviews with the tutors to explore their perspectives of the module. Ethics approval was obtained. The document review indicated that EBM competencies were covered adequately, although critical appraisal only focused on randomised controlled trials and guidelines. Students had a positive attitude towards the module, but felt that they needed more support from the tutors. Tutors felt that students engaged actively in discussions, but experienced difficulties with understanding certain concepts of EBM. Furthermore, they felt that it was challenging explaining these via the online learning platform and saw the need to incorporate more advanced technology to better connect with the students. In their view the key to successful learning of EBM was to keep it relevant and applicable to everyday practice. Tutors also felt that an online module on EBM was advantageous, since doctors from all over the world were able to participate. Our study has shown that the online module on EBM was effective in increasing EBM knowledge and skills of postgraduate students and was well received by both students and tutors. Students and tutors experienced generic challenges that accompany any educational intervention of EBM (e.g. understanding difficult concepts), but in addition had to deal with challenges unique to the online learning environment. Teachers of EBM should acknowledge these so as to enhance and successfully implement EBM teaching and learning for all students.

Evaluation of cleaners for photovoltaic modules exposed in an outdoor environment

NASA Technical Reports Server (NTRS)

Knapp, W. D.

1979-01-01

Power recovery of silicone encapsulated and glass covered photovoltaic modules, exposed for two years to a suburban environment, was measured after washing with a variety of cleaners including detergents, abrasive soap, and hydrocarbon solvents. Silicone encapsulated modules in operating environments may experience significant power losses or require extensive periodic cleaning. Glass front-faced modules in similar situations are much less affected. Organic hydrocarbon solvents or abrasives were found to be about five times more effective than mild detergents in cleaning encapsulated modules.

SLAC modulator system improvements and reliability results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donaldson, A.R.

1998-06-01

In 1995, an improvement project was completed on the 244 klystron modulators in the linear accelerator. The modulator system has been previously described. This article offers project details and their resulting effect on modulator and component reliability. Prior to the project, the authors had collected four operating cycles (1991 through 1995) of MTTF data. In this discussion, the '91 data will be excluded since the modulators operated at 60 Hz. The five periods following the '91 run were reviewed due to the common repetition rate at 120 Hz.

Studying the Physical Basis of Global Warming: Thermal Effects of the Interaction between Radiation and Matter and Greenhouse Effect

ERIC Educational Resources Information Center

Besson, Ugo; De Ambrosis, Anna; Mascheretti, Paolo

2010-01-01

We present a teaching module dealing with the thermal effects of interaction between radiation and matter, the infrared emission of bodies and the greenhouse effect devoted to university level and teacher education. The module stresses the dependence of the optical properties of materials (transparency, absorptivity and emissivity) on radiation…

It Is Not What You Expect: Dissociating Conflict Adaptation from Expectancies in a Stroop Task

ERIC Educational Resources Information Center

Jimenez, Luis; Mendez, Amavia

2013-01-01

In conflict tasks, congruency effects are modulated by the sequence of preceding trials. This modulation effect has been interpreted as an influence of a proactive mechanism of adaptation to conflict (Botvinick, Nystrom, Fissell, Carter, & Cohen, 1999), but the possible contribution of explicit expectancies to this adaptation effect remains…

Modulational instability of beat waves in a transversely magnetized plasma: Ion effects

NASA Astrophysics Data System (ADS)

Ferdous, T.; Amin, M. R.; Salimullah, M.

1996-05-01

The effect of ion dynamics on the modulational instability of the electrostatic beat wave at the difference frequency of two incident laser beams in a hot, collisionless, and transversely magnetized plasma has been studied theoretically. The full Vlasov equation in terms of gyrokinetic variables is employed to obtain the nonlinear response of ions and electrons. It is found that the growth rate of modulational instability is about two orders higher when ion motions are included.

Demonstration of a simplified optical mouse lighting module by integrating the non-Lambertian LED chip and the free-form surface.

PubMed

Pan, Jui-Wen; Tu, Sheng-Han

2012-05-20

A cost-effective, high-throughput, and high-yield method for the efficiency enhancement of an optical mouse lighting module is proposed. We integrated imprinting technology and free-form surface design to obtain a lighting module with high illumination efficiency and uniform intensity distribution. The imprinting technique can increase the light extraction efficiency and modulate the intensity distribution of light-emitting diodes. A modulated light source was utilized to add a compact free-form surface element to create a lighting module with 95% uniformity and 80% optical efficiency.

Diabetes attenuates urothelial modulation of detrusor contractility and spontaneous activity.

PubMed

Wang, Yi; Tar, Moses T; Fu, Shibo; Melman, Arnold; Davies, Kelvin P

2014-10-01

To investigate the effect of diabetes on urothelial modulation of bladder contractility. Bladder strips (urothelium intact or denuded) were prepared from 8-week-old streptozotocin-induced diabetic (n = 19) and non-diabetic control rats (n = 10). The effect of modulators of MaxiK (iberiotoxin and tetraethylammonium) and Kv7 (XE991 and retigabine) potassium channel activity were investigated for their effects on both carbachol-induced force generation and spontaneous contractile activity. In bladder strips from non-diabetic animals, the presence of the urothelium resulted in marked sensitivity to carbachol-induced force generation by modulators of MaxiK and Kv7 channel activity, whereas in the diabetic animal urothelial sensitivity to these agents was significantly diminished. Urothelial-intact bladder strips from non-diabetic animals were more sensitive to modulators of Kv7 activity in reducing the amplitude of spontaneous phasic contractions than urothelial-denuded bladder strips, whereas in diabetic animals the presence or absence of the urothelium did not alter the sensitivity to modulators of Kv7 activity. Spontaneous activity in the presence of tetraethylammonium was not affected by the urothelium in bladder strips from either diabetic or non-diabetic animals. The presence of the urothelium in bladders from non-diabetic animals modulates the activity of potassium blockers to affect bladder contractility, whereas in the diabetic bladder this effect is attenuated. These findings could help to explain the lack of success of pharmaceutical treatments targeting potassium channels to treat bladder pathology in patients with diseases imparing urothelial function. © 2014 The Japanese Urological Association.

Delta-9-Tetrahydrocannabinol Potentiates Fear Memory Salience Through Functional Modulation of Mesolimbic Dopaminergic Activity States.

PubMed

Fitoussi, Aurelie; Zunder, Jordan; Tan, Huibing; Laviolette, Steven R

2018-05-18

Chronic or acute exposure to delta-9-tetrahydrocannabinol (THC), the main psychoactive compound in cannabis, has been associated with numerous neuropsychiatric side-effects, including dysregulation of emotional processing and associative memory formation. Clinical and pre-clinical evidence suggests that the effects of THC are due to the ability to modulate mesolimbic dopamine (DA) activity states in the nucleus accumbens (NAc) and ventral tegmental area (VTA). Nevertheless, the mechanisms by which THC modulates mesolimbic DA function and emotional processing are not well understood. Using an olfactory associative fear memory procedure combined with in vivo neuronal electrophysiology, we examined the effects of direct THC microinfusions targeting the shell region of the NAc (NASh) and examined how THC may modulate the processing of fear-related emotional memory and concomitant activity states of the mesolimbic DA system. We report that intra-NASh THC dose-dependently potentiates the emotional salience of normally sub-threshold fear-conditioning cues. These effects were dependent upon intra-VTA transmission through GABAergic receptor mechanisms and intra-NASh DAergic transmission. Furthermore, doses of intra-NASh THC that potentiated fear memory salience were found to modulate intra-VTA neuronal network activity by increasing the spontaneous firing and bursting frequency of DAergic neurons whilst decreasing the activity levels of a subpopulation of putative GABAergic VTA neurons. These findings demonstrate that THC can act directly in the NASh to modulate mesolimbic activity states and induce disturbances in emotional salience and memory formation through modulation of VTA DAergic transmission. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Online Chemistry Modules: Interaction and Effective Faculty Facilitation

ERIC Educational Resources Information Center

Slocum, Laura E.; Towns Marcy Hamby; Zielinski, Theresa Julia

2004-01-01

Computer supported collaborative learning, cooperative learning combined with electronic communication, physical chemistry online modules, use of discussion boards, its advantages and limitations are experimented and discussed. The most important finding is the example of effective online faculty facilitation and interaction.

Adrenal-derived stress hormones modulate ozone-induced lung injury and inflammation

EPA Science Inventory

Ozone-induced systemic effects are modulated through activation of the neuro-hormonal stress response pathway. Adrenal demedullation (DEMED)or bilateral total adrenalectomy (ADREX) inhibits systemic and pulmonary effect of acute ozone exposure. To understand the influence of adre...

Flavonoid nutraceuticals and ionotropic receptors for the inhibitory neurotransmitter GABA.

PubMed

Johnston, Graham A R

2015-10-01

Flavonoids that are found in nutraceuticals have many and varied effects on the activation of ionotropic receptors for GABA, the major inhibitory neurotransmitter in our brains. They can act as positive or negative modulators enhancing or reducing the effect of GABA. They can act as allosteric agonists. They can act to modulate the action of other modulators. There is considerable evidence that these flavonoids are able to enter the brain to influence brain function. They may have a range of effects including relief of anxiety, improvement in cognition, acting as neuroprotectants and as sedatives. All of these effects are sought after in nutraceuticals. A number of studies have likened flavonoids to the widely prescribed benzodiazepines as 'a new family of benzodiazepine receptor ligands'. They are much more than that with many flavonoid actions on ionotropic GABA receptors being insensitive to the classic benzodiazepine antagonist flumazenil and thus independent of the classic benzodiazepine actions. It is time to consider flavonoids in their own right as important modulators of these vital receptors in brain function. Flavonoids are rarely consumed as a single flavonoid except as dietary supplements. The effects of mixtures of flavonoids and other modulators on GABAA receptors need to be more thoroughly investigated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dependence of the Martian radiation environment on atmospheric depth: Modeling and measurement

NASA Astrophysics Data System (ADS)

Guo, Jingnan; Slaba, Tony C.; Zeitlin, Cary; Wimmer-Schweingruber, Robert F.; Badavi, Francis F.; Böhm, Eckart; Böttcher, Stephan; Brinza, David E.; Ehresmann, Bent; Hassler, Donald M.; Matthiä, Daniel; Rafkin, Scot

2017-02-01

The energetic particle environment on the Martian surface is influenced by solar and heliospheric modulation and changes in the local atmospheric pressure (or column depth). The Radiation Assessment Detector (RAD) on board the Mars Science Laboratory rover Curiosity on the surface of Mars has been measuring this effect for over four Earth years (about two Martian years). The anticorrelation between the recorded surface Galactic Cosmic Ray-induced dose rates and pressure changes has been investigated by Rafkin et al. (2014) and the long-term solar modulation has also been empirically analyzed and modeled by Guo et al. (2015). This paper employs the newly updated HZETRN2015 code to model the Martian atmospheric shielding effect on the accumulated dose rates and the change of this effect under different solar modulation and atmospheric conditions. The modeled results are compared with the most up-to-date (from 14 August 2012 to 29 June 2016) observations of the RAD instrument on the surface of Mars. Both model and measurements agree reasonably well and show the atmospheric shielding effect under weak solar modulation conditions and the decline of this effect as solar modulation becomes stronger. This result is important for better risk estimations of future human explorations to Mars under different heliospheric and Martian atmospheric conditions.

DPSK-3ASK transmission optimization by adapting modulation levels

NASA Astrophysics Data System (ADS)

Eiselt, Michael H.; Teipen, Brian T.

2008-11-01

For metro and regional 100-Gbps transmission, a transparent channel reach of 500-600 km is required and a 100-GHz channel grid is typically used. For these applications, a cost effective modulation format is introduced which can make use of electronic components designed for the already established 40-Gbps market, bypassing the requirements for novel electronic developments and therefore reducing the component cost. With this DPSK-3ASK modulation format, five information bits are transmitted in two consecutive symbols, leading to a symbol rate of 45 Gbaud, including overhead for framing and FEC. To minimize hardware requirements and to create a cost-effective solution, a single Mach-Zehnder modulator can be used to create the optical DPSK-3ASK signal after combining the phase and amplitude modulation signals into a 6-level modulator drive voltage. In this paper, it is demonstrated by numerical simulations that these voltage levels can be modified to adapt to varying signal distortions and thereby yield improved transmission performance. It is shown that by dynamically modifying the modulation levels based on the channel performance, dynamic signal impairments such as the non-linear effects from varying power levels, changes in chromatic dispersion, or varying PMD levels can be mitigated. Error-free performance (with FEC) can be obtained with 24 dB OSNR and 7ps DGD for a 112-Gbps (45-Gbaud) optical signal.

Buffering of protons released by mineral formation during amelogenesis in mice.

PubMed

Bronckers, Antonius L J J; Lyaruu, Don M; Jalali, Rozita; DenBesten, Pamela K

2016-10-01

Regulation of pH by ameloblasts during amelogenesis is critical for enamel mineralization. We examined the effects of reduced bicarbonate secretion and the presence or absence of amelogenins on ameloblast modulation and enamel mineralization. To that end, the composition of fluorotic and non-fluorotic enamel of several different mouse mutants, including enamel of cystic fibrosis transmembrane conductance regulator-deficient (Cftr null), anion exchanger-2-deficient (Ae2a,b null), and amelogenin-deficient (Amelx null) mice, was determined by quantitative X-ray microanalysis. Correlation analysis was carried out to compare the effects of changes in the levels of sulfated-matrix (S) and chlorine (Cl; for bicarbonate secretion) on mineralization and modulation. The chloride (Cl - ) levels in forming enamel determined the ability of ameloblasts to modulate, remove matrix, and mineralize enamel. In general, the lower the Cl - content, the stronger the negative effects. In Amelx-null mice, modulation was essentially normal and the calcium content was reduced least. Retention of amelogenins in enamel of kallikrein-4-deficient (Klk4-null) mice resulted in decreased mineralization and reduced the length of the first acid modulation band without changing the total length of all acidic bands. These data suggest that buffering by bicarbonates is critical for modulation, matrix removal and enamel mineralization. Amelogenins also act as a buffer but are not critical for modulation. © 2016 Eur J Oral Sci.

Accurate and cost-effective MTF measurement system for lens modules of digital cameras

NASA Astrophysics Data System (ADS)

Chang, Gao-Wei; Liao, Chia-Cheng; Yeh, Zong-Mu

2007-01-01

For many years, the widening use of digital imaging products, e.g., digital cameras, has given rise to much attention in the market of consumer electronics. However, it is important to measure and enhance the imaging performance of the digital ones, compared to that of conventional cameras (with photographic films). For example, the effect of diffraction arising from the miniaturization of the optical modules tends to decrease the image resolution. As a figure of merit, modulation transfer function (MTF) has been broadly employed to estimate the image quality. Therefore, the objective of this paper is to design and implement an accurate and cost-effective MTF measurement system for the digital camera. Once the MTF of the sensor array is provided, that of the optical module can be then obtained. In this approach, a spatial light modulator (SLM) is employed to modulate the spatial frequency of light emitted from the light-source. The modulated light going through the camera under test is consecutively detected by the sensors. The corresponding images formed from the camera are acquired by a computer and then, they are processed by an algorithm for computing the MTF. Finally, through the investigation on the measurement accuracy from various methods, such as from bar-target and spread-function methods, it appears that our approach gives quite satisfactory results.

Aging and List-Wide Modulations of Strategy Execution:A Study in Arithmetic.

PubMed

Hinault, Thomas; Lemaire, Patrick

2017-01-01

Background/Study Context: This study aimed at further our understanding of the cognitive processes involved during strategy execution, and how the processes involved change with age. More specifically, the main goal was to investigate whether poorer-strategy effects (i.e., poorer performance when a cued strategy is not the best) and sequential modulations of poorer-strategy effects (i.e., decreased poorer-strategy effects on current problems following poorer-strategy problems compared with after better-strategy problems) are influenced by proportions of poorer-strategy problems. We used a computational estimation task (i.e., providing approximate products to two-digit multiplication problems such as 38 × 74) with problems sets including 75%, 50%, or 25% of poorer-strategy problems (i.e., participants have to estimate products with another strategy than the better strategy). The remaining problems were cued with the better strategy. Age-related differences were also investigated. We found that proportions of poorer-strategy problems influenced sequential modulations of poorer-strategy effects. Indeed, sequential modulations of poorer-strategy effects were larger when proportions of poorer-strategy problems were equal than unequal. Moreover, proportion effects were different for young and older adults, as older adults benefited more from low proportions of poorer-strategy problems compared with young adults. These findings have important implications regarding cognitive control mechanisms underlying both list-wide and trial-to-trial modulations of strategy execution, and how these processes change during aging.

Effects of single cycle binaural beat duration on auditory evoked potentials.

PubMed

Mihajloski, Todor; Bohorquez, Jorge; Özdamar, Özcan

2014-01-01

Binaural beat (BB) illusions are experienced as continuous central pulsations when two sounds with slightly different frequencies are delivered to each ear. It has been shown that steady-state auditory evoked potentials (AEPs) to BBs can be captured and investigated. The authors recently developed a new method of evoking transient AEPs to binaural beats using frequency modulated stimuli. This methodology was able to create single BBs in predetermined intervals with varying carrier frequencies. This study examines the effects of the BB duration and the frequency modulating component of the stimulus on the binaural beats and their evoked potentials. Normal hearing subjects were tested with a set of four durations (25, 50, 100, and 200 ms) with two stimulation configurations, binaural dichotic (binaural beats) and diotic (frequency modulation). The results obtained from the study showed that out of the given durations, the 100 ms beat, was capable of evoking the largest amplitude responses. The frequency modulation effect showed a decrease in peak amplitudes with increasing beat duration until their complete disappearance at 200 ms. Even though, at 200 ms, the frequency modulation effects were not present, the binaural beats were still perceived and captured as evoked potentials.

Focus modulation of cylindrical vector beams by using 1D photonic crystal lens with negative refraction effect.

PubMed

Xu, Ji; Zhong, Yi; Wang, Shengming; Lu, Yunqing; Wan, Hongdan; Jiang, Jian; Wang, Jin

2015-10-19

Sub-wavelength focusing of cylindrical vector beams (CVBs) has attracted great attention due to the specific physical effects and the applications in many areas. More powerful, flexible and effective ways to modulate the focus transversally and also longitudinally are always being pursued. In this paper, cylindrically symmetric lens composed of negative-index one-dimensional photonic crystal is proposed to make a breakthrough. By revealing the relationship between focal length and the exit surface shape of the lens, a quite simple and effective principle of designing the lens structure is presented to realize specific focus modulation. Plano-concave lenses are parameterized to modulate the focal length and the number of focuses. An axicon constructed by one-dimensional photonic crystal is proposed for the first time to obtain a large depth of focus and an optical needle focal field with almost a theoretical minimum FWHM of 0.362λ is achieved under radially polarized incident light. Because of the almost identical negative refractive index for TE and TM polarization states, all the modulation methods can be applied for any arbitrary polarized CVBs. This work offers a promising methodology for designing negative-index lenses in related application areas.

Systematic review of modulators of benzodiazepine receptors in irritable bowel syndrome: Is there hope?

PubMed Central

Salari, Pooneh; Abdollahi, Mohammad

2011-01-01

Several drugs are used in the treatment of irritable bowel syndrome (IBS) but all have side effects and variable efficacy. Considering the role of the gut-brain axis, immune, neural, and endocrine pathways in the pathogenesis of IBS and possible beneficial effects of benzodiazepines (BZD) in this axis, the present systematic review focuses on the efficacy of BZD receptor modulators in human IBS. For the years 1966 to February 2011, all literature was searched for any articles on the use of BZD receptor modulators and IBS. After thorough evaluation and omission of duplicate data, 10 out of 69 articles were included. BZD receptor modulators can be helpful, especially in the diarrhea-dominant form of IBS, by affecting the inflammatory, neural, and psychologic pathways, however, controversies still exist. Recently, a new BZD receptor modulator, dextofisopam was synthesized and studied in human subjects, but the studies are limited to phase IIb clinical trials. None of the existing trials considered the neuroimmunomodulatory effect of BZDs in IBS, but bearing in mind the concentration-dependent effect of BZDs on cytokines and cell proliferation, future studies using pharmacodynamic and pharmacokinetic approaches are highly recommended. PMID:22090780

Microwave influence on the isolated heart function. 1: Effect of modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pakhomov, A.G.; Dubovick, B.V.; Degtyariov, I.G.

1995-09-01

Dependence of the microwave effect on modulation parameters (pulse width, duty ratio, and peak intensity) was studied in an isolated frog auricle preparation. The rate and amplitude of spontaneous auricle twitches were measured during and after a 2 min exposure to 915 or 885 MHz microwaves and were compared to preexposure values. The studied ranges of modulation parameters were: pulse width, 10{sup {minus}6}--10{sup {minus}2} s; duty ratio, 7:100000, and peak specific absorption rate, 100--3,000 W/kg. Combinations of the parameters were chosen by chance, and about 400 various exposure regimes were tested. The experiments established that no regime was effective unlessmore » the average microwave power was high enough to induce preparation heating (0.1--0.4 C). The twitch rate instantly increased, and the amplitude decreased, as the temperature rose; similar changes could be induced by equivalent conventional heating. the data provide evidence that the effect of short-term microwave exposure on the isolated heart pacemaker and contractile functions depends on pulse modulation just as much as modulation determines the average absorbed power. These functions demonstrated no specific dependence on exposure parameters such as frequency or power windows.« less

Additive mixture effects of estrogenic chemicals in human cell-based assays can be influenced by inclusion of chemicals with differing effect profiles.

PubMed

Evans, Richard Mark; Scholze, Martin; Kortenkamp, Andreas

2012-01-01

A growing body of experimental evidence indicates that the in vitro effects of mixtures of estrogenic chemicals can be well predicted from the estrogenicity of their components by the concentration addition (CA) concept. However, some studies have observed small deviations from CA. Factors affecting the presence or observation of deviations could include: the type of chemical tested; number of mixture components; mixture design; and assay choice. We designed mixture experiments that address these factors, using mixtures with high numbers of components, chemicals from diverse chemical groups, assays with different in vitro endpoints and different mixture designs and ratios. Firstly, the effects of mixtures composed of up to 17 estrogenic chemicals were examined using estrogenicity assays with reporter-gene (ERLUX) and cell proliferation (ESCREEN) endpoints. Two mixture designs were used: 1) a 'balanced' design with components present in proportion to a common effect concentration (e.g. an EC(10)) and 2) a 'non-balanced' design with components in proportion to potential human tissue concentrations. Secondly, the individual and simultaneous ability of 16 potential modulator chemicals (each with minimal estrogenicity) to influence the assay outcome produced by a reference mixture of estrogenic chemicals was examined. Test chemicals included plasticizers, phthalates, metals, PCBs, phytoestrogens, PAHs, heterocyclic amines, antioxidants, UV filters, musks, PBDEs and parabens. In all the scenarios tested, the CA concept provided a good prediction of mixture effects. Modulation studies revealed that chemicals possessing minimal estrogenicity themselves could reduce (negatively modulate) the effect of a mixture of estrogenic chemicals. Whether the type of modulation we observed occurs in practice most likely depends on the chemical concentrations involved, and better information is required on likely human tissue concentrations of estrogens and of potential modulators. Successful prediction of the effects of diverse chemical combinations might be more likely if chemical profiling included consideration of effect modulation.

Additive Mixture Effects of Estrogenic Chemicals in Human Cell-Based Assays Can Be Influenced by Inclusion of Chemicals with Differing Effect Profiles

PubMed Central

Evans, Richard Mark; Scholze, Martin; Kortenkamp, Andreas

2012-01-01

A growing body of experimental evidence indicates that the in vitro effects of mixtures of estrogenic chemicals can be well predicted from the estrogenicity of their components by the concentration addition (CA) concept. However, some studies have observed small deviations from CA. Factors affecting the presence or observation of deviations could include: the type of chemical tested; number of mixture components; mixture design; and assay choice. We designed mixture experiments that address these factors, using mixtures with high numbers of components, chemicals from diverse chemical groups, assays with different in vitro endpoints and different mixture designs and ratios. Firstly, the effects of mixtures composed of up to 17 estrogenic chemicals were examined using estrogenicity assays with reporter-gene (ERLUX) and cell proliferation (ESCREEN) endpoints. Two mixture designs were used: 1) a ‘balanced’ design with components present in proportion to a common effect concentration (e.g. an EC10) and 2) a ‘non-balanced’ design with components in proportion to potential human tissue concentrations. Secondly, the individual and simultaneous ability of 16 potential modulator chemicals (each with minimal estrogenicity) to influence the assay outcome produced by a reference mixture of estrogenic chemicals was examined. Test chemicals included plasticizers, phthalates, metals, PCBs, phytoestrogens, PAHs, heterocyclic amines, antioxidants, UV filters, musks, PBDEs and parabens. In all the scenarios tested, the CA concept provided a good prediction of mixture effects. Modulation studies revealed that chemicals possessing minimal estrogenicity themselves could reduce (negatively modulate) the effect of a mixture of estrogenic chemicals. Whether the type of modulation we observed occurs in practice most likely depends on the chemical concentrations involved, and better information is required on likely human tissue concentrations of estrogens and of potential modulators. Successful prediction of the effects of diverse chemical combinations might be more likely if chemical profiling included consideration of effect modulation. PMID:22912892

Conversion of the LXR-agonist TO-901317--from inverse to normal modulation of gamma-secretase by addition of a carboxylic acid and a lipophilic anchor.

PubMed

Narlawar, Rajeshwar; Baumann, Karlheinz; Czech, Christian; Schmidt, Boris

2007-10-01

TO-901317, a LXR agonist, is an inverse modulator of Alzheimer's disease associated gamma-secretase. We synthesized TO-901317 analogous compound but replaced the hexafluorocarbinol moiety by an oxyacetic acid functionality and hypothesized that the replacement would change the mode of action from an inverse modulation to normal modulation of gamma-secretase. As anticipated, acid 9 was found to be an effective modulator of gamma-secretase and displayed activity at low micromolar concentration. This significant modification can be applied to several inverse gamma-secretase modulators. Such modulators may preserve the cleavage of other gamma-secretase substrates such as Notch.

Mike Kempe | NREL

Science.gov Websites

cells and modules. His work concerns primarily modeling and measuring moisture ingress into PV modules and studying the effect of moisture on polymer adhesion, device performance, and component corrosion Photovoltaic Modules." Solar Energy Materials and Solar Cells, 90: 2720-2738. View all NREL publications

Experimental Observation of Thermal Self-Modulation in OPO

NASA Technical Reports Server (NTRS)

Gao, Jiangrui; Wang, Hai; Xie, Changde; Peng, Kunchi

1996-01-01

The thermal self-modulation has been observed experimentally via SHG in OPO. The threshold pump power for the thermal self- modulation is much smaller than that of the nonlinear self-pulsing. The thermal effect prevent from realizing the theoretical prediction for the self-pulsing.

Decoupled Modulation Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Shaobu; Huang, Renke; Huang, Zhenyu

The objective of this research work is to develop decoupled modulation control methods for damping inter-area oscillations with low frequencies, so the damping control can be more effective and easier to design with less interference among different oscillation modes in the power system. A signal-decoupling algorithm was developed that can enable separation of multiple oscillation frequency contents and extraction of a “pure” oscillation frequency mode that are fed into Power System Stabilizers (PSSs) as the modulation input signals. As a result, instead of introducing interferences between different oscillation modes from the traditional approaches, the output of the new PSS modulationmore » control signal mainly affects only one oscillation mode of interest. The new decoupled modulation damping control algorithm has been successfully developed and tested on the standard IEEE 4-machine 2-area test system and a minniWECC system. The results are compared against traditional modulation controls, which demonstrates the validity and effectiveness of the newly-developed decoupled modulation damping control algorithm.« less

The issue of FM to AM conversion on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Browning, D F; Rothenberg, J E; Wilcox, R B

1998-08-13

The National Ignition Facility (NIF) baseline configuration for inertial confinement fusion requires phase modulation for two purposes. First, ~ 1Å of frequency modulation (FM) bandwidth at low modulation frequency is required to suppress buildup of Stimulated Brioullin Scattering (SBS) in the large aperture laser optics. Also ~ 3 Å or more bandwidth at high modulation frequency is required for smoothing of the speckle pattern illuminating the target by the smoothing by spectral dispersion method (SSD). Ideally, imposition of bandwidth by pure phase modulation does not affect the beam intensity. However, as a result of a large number of effects, themore » FM converts to amplitude modulation (AM). In general this adversely affects the laser performance, e.g. by reducing the margin against damage to the optics. In particular, very large conversion of FM to AM has been observed in the NIF all-fiber master oscillator and distribution systems. The various mechanisms leading to AM are analyzed and approaches to minimizing their effects are discussed.« less

Effects of a Science Education Module on Attitudes towards Modern Biotechnology of Secondary School Students

NASA Astrophysics Data System (ADS)

Klop, Tanja; Severiens, Sabine E.; Knippels, Marie-Christine P. J.; van Mil, Marc H. W.; Ten Dam, Geert T. M.

2010-06-01

This article evaluated the impact of a four-lesson science module on the attitudes of secondary school students. This science module (on cancer and modern biotechnology) utilises several design principles, related to a social constructivist perspective on learning. The expectation was that the module would help students become more articulate in this particular field. In a quasi-experimental design (experimental-, control groups, and pre- and post-tests), secondary school students' attitudes (N = 365) towards modern biotechnology were measured by a questionnaire. Data were analysed using Chi-square tests. Significant differences were obtained between the control and experimental conditions. Results showed that the science module had a significant effect on attitudes, although predominantly towards a more supportive and not towards a more critical stance. It is discussed that offering a science module of this kind can indeed encourage students to become more aware of modern biotechnology, although promoting a more critical attitude towards modern biotechnology should receive more attention.

The effects of hormones and physical exercise on hippocampal structural plasticity.

PubMed

Triviño-Paredes, Juan; Patten, Anna R; Gil-Mohapel, Joana; Christie, Brian R

2016-04-01

The hippocampus plays an integral role in certain aspects of cognition. Hippocampal structural plasticity and in particular adult hippocampal neurogenesis can be influenced by several intrinsic and extrinsic factors. Here we review how hormones (i.e., intrinsic modulators) and physical exercise (i.e., an extrinsic modulator) can differentially modulate hippocampal plasticity in general and adult hippocampal neurogenesis in particular. Specifically, we provide an overview of the effects of sex hormones, stress hormones, and metabolic hormones on hippocampal structural plasticity and adult hippocampal neurogenesis. In addition, we also discuss how physical exercise modulates these forms of hippocampal plasticity, giving particular emphasis on how this modulation can be affected by variables such as exercise regime, duration, and intensity. Understanding the neurobiological mechanisms underlying the modulation of hippocampal structural plasticity by intrinsic and extrinsic factors will impact the design of new therapeutic approaches aimed at restoring hippocampal plasticity following brain injury or neurodegeneration. Copyright © 2016 Elsevier Inc. All rights reserved.

Two-dimensional modulated ion-acoustic excitations in electronegative plasmas

NASA Astrophysics Data System (ADS)

Panguetna, Chérif S.; Tabi, Conrad B.; Kofané, Timoléon C.

2017-09-01

Two-dimensional modulated ion-acoustic waves are investigated in an electronegative plasma. Through the reductive perturbation expansion, the governing hydrodynamic equations are reduced to a Davey-Stewartson system with two-space variables. The latter is used to study the modulational instability of ion-acoustic waves along with the effect of plasma parameters, namely, the negative ion concentration ratio (α) and the electron-to-negative ion temperature ratio (σn). A parametric analysis of modulational instability is carried out, where regions of plasma parameters responsible for the emergence of modulated ion-acoustic waves are discussed, with emphasis on the behavior of the instability growth rate. Numerically, using perturbed plane waves as initial conditions, parameters from the instability regions give rise to series of dromion solitons under the activation of modulational instability. The sensitivity of the numerical solutions to plasma parameters is discussed. Some exact solutions in the form one- and two-dromion solutions are derived and their response to the effect of varying α and σn is discussed as well.

FM-to-AM modulations induced by a weak residual reflection stack of sine-modulated pulses in inertial confinement fusion laser systems

NASA Astrophysics Data System (ADS)

Huang, Xiaoxia; Deng, Xuewei; Zhou, Wei; Hu, Dongxia; Guo, Huaiwen; Wang, Yuancheng; Zhao, Bowang; Zhong, Wei; Deng, Wu

2018-02-01

We report on frequency to amplitude modulation (FM-to-AM) conversion induced by a weak residual reflection stack of sine-modulated pulses in a complex laser system. Theoretical and experimental investigations reveal that when weak residual reflected pulses stack on the main pulse, the spectral intensity changes in the stacked region, which then converts to obvious AM. This kind of FM-to-AM effect often occurs in the tail of the pulse and cannot be eliminated by common compensation methods, which even enhance the modulation depth. Furthermore, the actual intensity modulation frequency and depth induced by the residual reflection stack are much higher and deeper than observed on the oscilloscope, which is harmful for safe operation of the laser facility and the driving power balance during inertial confinement fusion. To eliminate this kind of FM-to-AM effect, any possible on-axis and near-axis residual reflection in laser systems must be avoided.

Directly Phase-Modulated Light Source

NASA Astrophysics Data System (ADS)

Yuan, Z. L.; Fröhlich, B.; Lucamarini, M.; Roberts, G. L.; Dynes, J. F.; Shields, A. J.

2016-07-01

The art of imparting information onto a light wave by optical signal modulation is fundamental to all forms of optical communication. Among many schemes, direct modulation of laser diodes stands out as a simple, robust, and cost-effective method. However, the simultaneous changes in intensity, frequency, and phase have prevented its application in the field of secure quantum communication. Here, we propose and experimentally demonstrate a directly phase-modulated light source which overcomes the main disadvantages associated with direct modulation and is suitable for diverse applications such as coherent communications and quantum cryptography. The source separates the tasks of phase preparation and pulse generation between a pair of semiconductor lasers leading to very pure phase states. Moreover, the cavity-enhanced electro-optic effect enables the first example of subvolt half-wave phase modulation at high signal rates. The source is compact, stable, and versatile, and we show its potential to become the standard transmitter for future quantum communication networks based on attenuated laser pulses.

KENNEDY SPACE CENTER, FLA. - Executive Director of NASDA Koji Yamamoto (left) and Center Director Roy Bridges Jr. (right) exchange mementos during Mr. Yamamoto’s visit to KSC. Mr. Bridges also holds the logo of the new Japan Aerospace Exploration Agency, a merger of three Japanese aeronautical and space agencies effective Oct.1, 2003. Mr. Yamamoto is at KSC for a welcome ceremony involving the arrival of the newest Space Station module, the Japanese Experiment Module/pressurized module. His visit includes a tour of the Columbia Debris Hangar.

NASA Image and Video Library

2003-06-12

KENNEDY SPACE CENTER, FLA. - Executive Director of NASDA Koji Yamamoto (left) and Center Director Roy Bridges Jr. (right) exchange mementos during Mr. Yamamoto’s visit to KSC. Mr. Bridges also holds the logo of the new Japan Aerospace Exploration Agency, a merger of three Japanese aeronautical and space agencies effective Oct.1, 2003. Mr. Yamamoto is at KSC for a welcome ceremony involving the arrival of the newest Space Station module, the Japanese Experiment Module/pressurized module. His visit includes a tour of the Columbia Debris Hangar.

KENNEDY SPACE CENTER, FLA. - Executive Director of NASDA Koji Yamamoto (left) is welcomed to KSC by Center Director Roy Bridges Jr. (right). On the table between them is the logo of the new Japan Aerospace Exploration Agency, a merger of three Japanese aeronautical and space agencies effective Oct.1, 2003. Mr. Yamamoto is at KSC for a welcome ceremony involving the arrival of the newest Space Station module, the Japanese Experiment Module/pressurized module. His visit includes a tour of the Columbia Debris Hangar.

NASA Image and Video Library

2003-06-12

KENNEDY SPACE CENTER, FLA. - Executive Director of NASDA Koji Yamamoto (left) is welcomed to KSC by Center Director Roy Bridges Jr. (right). On the table between them is the logo of the new Japan Aerospace Exploration Agency, a merger of three Japanese aeronautical and space agencies effective Oct.1, 2003. Mr. Yamamoto is at KSC for a welcome ceremony involving the arrival of the newest Space Station module, the Japanese Experiment Module/pressurized module. His visit includes a tour of the Columbia Debris Hangar.

Applications of thermoelectric modules on heat flow detection.

PubMed

Leephakpreeda, Thananchai

2012-03-01

This paper presents quantitative analysis and practical scenarios of implementation of the thermoelectric module for heat flow detection. Mathematical models of the thermoelectric effects are derived to describe the heat flow from/to the detected media. It is observed that the amount of the heat flow through the thermoelectric module proportionally induces the conduction heat owing to the temperature difference between the hot side and the cold side of the thermoelectric module. In turn, the Seebeck effect takes place in the thermoelectric module where the temperature difference is converted to the electric voltage. Hence, the heat flow from/to the detected media can be observed from both the amount and the polarity of the voltage across the thermoelectric module. Two experiments are demonstrated for viability of the proposed technique by the measurements of the heat flux through the building wall and thermal radiation from the outdoor environment during daytime. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

Field-effect Flow Control in Polymer Microchannel Networks

NASA Technical Reports Server (NTRS)

Sniadecki, Nathan; Lee, Cheng S.; Beamesderfer, Mike; DeVoe, Don L.

2003-01-01

A new Bio-MEMS electroosmotic flow (EOF) modulator for plastic microchannel networks has been developed. The EOF modulator uses field-effect flow control (FEFC) to adjust the zeta potential at the Parylene C microchannel wall. By setting a differential EOF pumping rate in two of the three microchannels at a T-intersection with EOF modulators, the induced pressure at the intersection generated pumping in the third, field-free microchannel. The EOF modulators are able to change the magnitude and direction of the pressure pumping by inducing either a negative or positive pressure at the intersection. The flow velocity is tracked by neutralized fluorescent microbeads in the microchannels. The proof-of-concept of the EOF modulator described here may be applied to complex plastic ,microchannel networks where individual microchannel flow rates are addressable by localized induced-pressure pumping.

The effect of gravity modulation on thermosolutal convection

NASA Technical Reports Server (NTRS)

Saunders, Bonita V.; Murray, Bruce T.; Mcfadden, G. B.; Coriell, S. R.; Wheeler, A. A.

1992-01-01

In a gravitational field, the opposing effects of components of different diffusivities, for example, temperature and solute, in the density profile in a fluid may produce convective instabilities that exhibit a broad range of dynamical behavior. The effect of time periodic vertical gravity modulation on the onset of these instabilities in an infinite horizontal layer with stress free boundaries is examined. This work is viewed as a first step in expanding previous results in solidification to the full problem of characterizing the effects of gravity modulation in thermosolutal convection during the directional solidification of binary alloys. Calculations carried out both with and without steady background acceleration are presented, the latter results being relevant to microgravity conditions.

Timbral Sharpness and Modulations in Frequency and Amplitude: Implications for the Fusion of Musical Sounds.

NASA Astrophysics Data System (ADS)

Goad, Pamela Joy

The fusion of musical voices is an important aspect of musical blend, or the mixing of individual sounds. Yet, little research has been done to explicitly determine the factors involved in fusion. In this study, the similarity of timbre and modulation were examined for their contribution to the fusion of sounds. It is hypothesized that similar timbres will fuse better than dissimilar timbres, and, voices with the same kind of modulation will fuse better than voices of different modulations. A perceptually-based measure, known as sharpness was investigated as a measure of timbre. The advantages of using sharpness are that it is based on hearing sensitivities and masking phenomena of inner ear processing. Five musical instrument families were digitally recorded in performances across a typical playing range at two extreme dynamic levels. Analyses reveal that sharpness is capable of uncovering subtle changes in timbre including those found in musical dynamics, instrument design, and performer-specific variations. While these analyses alone are insufficient to address fusion, preliminary calculations of timbral combinations indicate that sharpness has the potential to predict the fusion of sounds used in musical composition. Three experiments investigated the effects of modulation on the fusion of a harmonic major sixth interval. In the first experiment using frequency modulation, stimuli varied in deviation about a mean fundamental frequency and relative modulation phase between the two tones. Results showed smaller frequency deviations promoted fusion and relative phase differences had a minimal effect. In a second experiment using amplitude modulation, stimuli varied in deviation about a mean amplitude level and relative phase of modulation. Results showed smaller amplitude deviations promoted better fusion, but unlike frequency modulation, relative phase differences were also important. In a third experiment, frequency modulation, amplitude modulation and mixed modulation were arranged in all possible voicings. Results showed frequency modulation in the lower voice and less variance in amplitude envelopes contributed to an increase in fusion. The theory that similar modulations would promote better fusion was only marginally supported. For these experiments, results revealed differences depending on modulation type and that a lesser amount of modulation fosters greater fusion.

Attitudes of health care students about computer-aided neuroanatomy instruction.

PubMed

McKeough, D Michael; Bagatell, Nancy

2009-01-01

This study examined students' attitudes toward computer-aided instruction (CAI), specifically neuroanatomy learning modules, to assess which components were primary in establishing these attitudes and to discuss the implications of these attitudes for successfully incorporating CAI in the preparation of health care providers. Seventy-seven masters degree, entry-level, health care professional students matriculated in an introductory neuroanatomy course volunteered as subjects for this study. Students independently reviewed the modules as supplements to lecture and completed a survey to evaluate teaching effectiveness. Responses to survey statements were compared across the learning modules to determine if students viewed the modules differently. Responses to individual survey statements were averaged to measure the strength of agreement or disagreement with the statement. Responses to open-ended questions were theme coded, and frequencies and percentages were calculated for each. Students saw no differences between the learning modules. Students perceived the learning modules as valuable; they enjoyed using the modules but did not prefer CAI over traditional lecture format. The modules were useful in learning or reinforcing neuroanatomical concepts and improving clinical problem-solving skills. Students reported that the visual representation of the neuroanatomical systems, computer animation, ability to control the use of the modules, and navigational fidelity were key factors in determining attitudes. The computer-based learning modules examined in this study were effective as adjuncts to lecture in helping entry-level health care students learn and make clinical applications of neuroanatomy information.

Waveguide-based electro-absorption modulator performance: comparative analysis

NASA Astrophysics Data System (ADS)

Amin, Rubab; Khurgin, Jacob B.; Sorger, Volker J.

2018-06-01

Electro-optic modulation is a key function for data communication. Given the vast amount of data handled, understanding the intricate physics and trade-offs of modulators on-chip allows revealing performance regimes not explored yet. Here we show a holistic performance analysis for waveguide-based electro-absorption modulators. Our approach centers around material properties revealing obtainable optical absorption leading to effective modal cross-section, and material broadening effects. Taken together both describe the modulator physical behavior entirely. We consider a plurality of material modulation classes to include two-level absorbers such as quantum dots, free carrier accumulation or depletion such as ITO or Silicon, two-dimensional electron gas in semiconductors such as quantum wells, Pauli blocking in Graphene, and excitons in two-dimensional atomic layered materials such as found in transition metal dichalcogendies. Our results show that reducing the modal area generally improves modulator performance defined by the amount of induced electrical charge, and hence the energy-per-bit function, required switching the signal. We find that broadening increases the amount of switching charge needed. While some material classes allow for reduced broadening such as quantum dots and 2-dimensional materials due to their reduced Coulomb screening leading to increased oscillator strengths, the sharpness of broadening is overshadowed by thermal effects independent of the material class. Further we find that plasmonics allows the switching charge and energy-per-bit function to be reduced by about one order of magnitude compared to bulk photonics. This analysis is aimed as a guide for the community to predict anticipated modulator performance based on both existing and emerging materials.

Noise-Coupled Image Rejection Architecture of Complex Bandpass ΔΣAD Modulator

NASA Astrophysics Data System (ADS)

San, Hao; Kobayashi, Haruo

This paper proposes a new realization technique of image rejection function by noise-coupling architecture, which is used for a complex bandpass ΔΣAD modulator. The complex bandpass ΔΣAD modulator processes just input I and Q signals, not image signals, and the AD conversion can be realized with low power dissipation. It realizes an asymmetric noise-shaped spectra, which is desirable for such low-IF receiver applications. However, the performance of the complex bandpass ΔΣAD modulator suffers from the mismatch between internal analog I and Q paths. I/Q path mismatch causes an image signal, and the quantization noise of the mirror image band aliases into the desired signal band, which degrades the SQNDR (Signal to Quantization Noise and Distortion Ratio) of the modulator. In our proposed modulator architecture, an extra notch for image rejection is realized by noise-coupled topology. We just add some passive capacitors and switches to the modulator; the additional integrator circuit composed of an operational amplifier in the conventional image rejection realization is not necessary. Therefore, the performance of the complex modulator can be effectively raised without additional power dissipation. We have performed simulation with MATLAB to confirm the validity of the proposed architecture. The simulation results show that the proposed architecture can achieve the realization of image-rejection effectively, and improve the SQNDR of the complex bandpass ΔΣAD modulator.

Unstart Coupling Mechanism Analysis of Multiple-Modules Hypersonic Inlet

PubMed Central

Wang, Lei; Cao, Shibin

2013-01-01

The combination of multiplemodules in parallel manner is an important way to achieve the much higher thrust of scramjet engine. For the multiple-modules scramjet engine, when inlet unstarted oscillatory flow appears in a single-module engine due to high backpressure, how to interact with each module by massflow spillage, and whether inlet unstart occurs in other modules are important issues. The unstarted flowfield and coupling characteristic for a three-module hypersonic inlet caused by center module II and side module III were, conducted respectively. The results indicate that the other two hypersonic inlets are forced into unstarted flow when unstarted phenomenon appears on a single-module hypersonic inlet due to high backpressure, and the reversed flow in the isolator dominates the formation, expansion, shrinkage, and disappearance of the vortexes, and thus, it is the major factor of unstart coupling of multiple-modules hypersonic inlet. The coupling effect among multiple modules makes hypersonic inlet be more likely unstarted. PMID:24348146

Vibration waveform effects on dynamic stabilization of ablative Rayleigh-Taylor instability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piriz, A. R.; Lucchio, L. Di; Rodriguez Prieto, G.

2011-08-15

An analysis of dynamic stabilization of Rayleigh-Taylor instability in an ablation front is performed by considering a general square wave for modulating the vertical acceleration of the front. Such a kind of modulation allows for clarifying the role of thermal conduction in the mechanism of dynamic stabilization. In addition, the study of the effect of different modulations by varying the duration and amplitude of the square wave in each half-period provides insight on the optimum performance of dynamic stabilization.

Preliminary Failure Modes and Effects Analysis of the US DCLL Test Blanket Module

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee C. Cadwallader

2010-06-01

This report presents the results of a preliminary failure modes and effects analysis (FMEA) of a small tritium-breeding test blanket module design for the International Thermonuclear Experimental Reactor. The FMEA was quantified with “generic” component failure rate data, and the failure events are binned into postulated initiating event families and frequency categories for safety assessment. An appendix to this report contains repair time data to support an occupational radiation exposure assessment for test blanket module maintenance.

Preliminary Failure Modes and Effects Analysis of the US DCLL Test Blanket Module

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee C. Cadwallader

2007-08-01

This report presents the results of a preliminary failure modes and effects analysis (FMEA) of a small tritium-breeding test blanket module design for the International Thermonuclear Experimental Reactor. The FMEA was quantified with “generic” component failure rate data, and the failure events are binned into postulated initiating event families and frequency categories for safety assessment. An appendix to this report contains repair time data to support an occupational radiation exposure assessment for test blanket module maintenance.

Ultrafast optical modulation of magneto-optical terahertz effects occurring in a graphene-loaded resonant metasurface

NASA Astrophysics Data System (ADS)

Zanotto, S.; Lange, C.; Maag, T.; Pitanti, A.; Miseikis, V.; Coletti, C.; Degl'Innocenti, R.; Baldacci, L.; Huber, R.; Tredicucci, A.

2016-09-01

In this paper we investigate the effect of a static magnetic field and of optical pumping on the transmittance of a hybrid graphene-split ring resonator metasurface. A significant modulation of the transmitted spectra is obtained, both by optical pumping, and by a combination of optical pumping and magnetostatic biasing. The transmittance modulation features spectral fingerprints that are characteristic of a non-trivial interplay between the bare graphene response and the split ring resonance.

Comprehensive, Mixed-Methods Assessment of a Blended Learning Model for Geospatial Literacy Instruction

NASA Astrophysics Data System (ADS)

Brodeur, J. J.; Maclachlan, J. C.; Bagg, J.; Chiappetta-Swanson, C.; Vine, M. M.; Vajoczki, S.

2013-12-01

Geospatial literacy -- the ability to conceptualize, capture, analyze and communicate spatial phenomena -- represents an important competency for 21st Century learners in a period of 'Geospatial Revolution'. Though relevant to in-course learning, these skills are often taught externally, placing time and resource pressures on the service providers - commonly libraries - that are relied upon to provide instruction. The emergence of online and blended modes of instruction has presented a potential means of increasing the cost-effectiveness of such activities, by simultaneously reducing instructional costs, expanding the audience for these resources, and addressing student preferences for asynchronous learning and '24-7' access. During 2011 and 2012, McMaster University Library coordinated the development, implementation and assessment of blended learning modules for geospatial literacy instruction in first-year undergraduate Social Science courses. In this paper, we present the results of a comprehensive mixed-methods approach to assess the efficacy of implementing blended learning modules to replace traditional (face-to-face), library-led, first-year undergraduate geospatial literacy instruction. Focus groups, personal interviews and an online survey were used to assess modules across dimensions of: student use, satisfaction and accessibility requirements (via Universal Instructional Design [UID] principles); instructor and teaching staff perception of pedagogical efficacy and instructional effectiveness; and, administrator cost-benefit assessment of development and implementation. Results showed that both instructors and students identified significant value in using the online modules in a blended-learning setting. Reaffirming assumptions of students' '24/7' learning preferences, over 80% of students reported using the modules on a repeat basis. Students were more likely to use the modules to better understand course content than simply to increase their grade in the course, which demonstrates applicability of the modules beyond a strict surface-learning approach. Instructors felt that giving students access to these modules increased flexibility in how in-class time was used, reduced student anxiety in busy lab sessions, and increased the effectiveness of face-to-face instruction and summative assessments. Though instructors perceived little to no change in grades as a result of the migration to blended-learning instruction, students overwhelmingly perceived a positive impact on their learning, as over 75% felt that the modules improved their geospatial literacy skills and general understanding in the course. Cost-benefit analyses proved challenging, as administrators struggled to estimate the true costs of both traditional instruction and module development. Recommendations for future module modification exposed the competing expectations of generalizing content to increase applicability and cost-effectiveness, versus tailoring modules to specific course content.

On the sensitivity of 4 different CPV module technologies to relevant ambient and operation conditions

NASA Astrophysics Data System (ADS)

Domínguez, César; Besson, Pierre

2014-09-01

The sensitivity of four different CPV module technologies to most operating conditions relevant to CPV systems has been studied, namely DNI, spectrum, cell and lens temperature and clearness of the sky. In order to isolate the influence of a single operation parameter, the analysis of long-term outdoor monitoring data is required. The effect of lens temperature on cell current has been found to vary greatly between modules due to the different optical architectures studied. Maximum sensitivity is found for silicone-on-glass primary lenses. The VOC thermal coefficient was found to vary between module technologies, probably due to differences in maximum local effective concentration.

Aircraft Noise Prediction Program theoretical manual: Propeller aerodynamics and noise

NASA Technical Reports Server (NTRS)

Zorumski, W. E. (Editor); Weir, D. S. (Editor)

1986-01-01

The prediction sequence used in the aircraft noise prediction program (ANOPP) is described. The elements of the sequence are called program modules. The first group of modules analyzes the propeller geometry, the aerodynamics, including both potential and boundary-layer flow, the propeller performance, and the surface loading distribution. This group of modules is based entirely on aerodynamic strip theory. The next group of modules deals with the first group. Predictions of periodic thickness and loading noise are determined with time-domain methods. Broadband noise is predicted by a semiempirical method. Near-field predictions of fuselage surface pressrues include the effects of boundary layer refraction and scattering. Far-field predictions include atmospheric and ground effects.

Convective and morphological instabilities during crystal growth: Effect of gravity modulation

NASA Technical Reports Server (NTRS)

Coreill, S. R.; Murray, B. T.; Mcfadden, G. B.; Wheeler, A. A.; Saunders, B. V.

1992-01-01

During directional solidification of a binary alloy at constant velocity in the vertical direction, morphological and convective instabilities may occur due to the temperature and solute gradients associated with the solidification process. The effect of time-periodic modulation (vibration) is studied by considering a vertical gravitational acceleration which is sinusoidal in time. The conditions for the onset of solutal convection are calculated numerically, employing two distinct computational procedures based on Floquet theory. In general, a stable state can be destabilized by modulation and an unstable state can be stabilized. In the limit of high frequency modulation, the method of averaging and multiple-scale asymptotic analysis can be used to simplify the calculations.

Using Interactive Technology to Support Students' Understanding of the Greenhouse Effect and Global Warming

ERIC Educational Resources Information Center

Varma, Keisha; Linn, Marcia C.

2012-01-01

In this work, we examine middle school students' understanding of the greenhouse effect and global warming. We designed and refined a technology-enhanced curriculum module called "Global Warming: Virtual Earth". In the module activities, students conduct virtual experiments with a visualization of the greenhouse effect. They analyze data and draw…

Numerical investigations of self- and cross-phase modulation effects in high-power fiber amplifiers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Zunoubi, Mohammad R.; Anderson, Brian; Naderi, Shadi A.; Madden, Timothy J.; Dajani, Iyad

2017-03-01

The development of high-power fiber lasers is of great interest due to the advantages they offer relative to other laser technologies. Currently, the maximum power from a reportedly single-mode fiber amplifier stands at 10 kW. Though impressive, this power level was achieved at the cost of a large spectral linewidth, making the laser unsuitable for coherent or spectral beam combination techniques required to reach power levels necessary for airborne tactical applications. An effective approach in limiting the SBS effect is to insert an electro-optic phase modulator at the low-power end of a master oscillator power amplifier (MOPA) system. As a result, the optical power is spread among spectral sidebands; thus raising the overall SBS threshold of the amplifier. It is the purpose of this work to present a comprehensive numerical scheme that is based on the extended nonlinear Schrodinger equations that allows for accurate analysis of phase modulated fiber amplifier systems in relation to the group velocity dispersion and Kerr nonlinearities and their effect on the coherent beam combining efficiency. As such, we have simulated a high-power MOPA system modulated via filtered pseudo-random bit sequence format for different clock rates and power levels. We show that at clock rates of ≥30 GHz, the combination of GVD and self-phase modulation may lead to a drastic drop in beam combining efficiency at the multi-kW level. Furthermore, we extend our work to study the effect of cross-phase modulation where an amplifier is seeded with two laser sources.

Power-law modulation of the scalar power spectrum from a heavy field with a monomial potential

NASA Astrophysics Data System (ADS)

Huang, Qing-Guo; Pi, Shi

2018-04-01

The effects of heavy fields modulate the scalar power spectrum during inflation. We analytically calculate the modulations of the scalar power spectrum from a heavy field with a separable monomial potential, i.e. V(phi)~ phin. In general the modulation is characterized by a power-law oscillation which is reduced to the logarithmic oscillation in the case of n=2.

Signal recognition and parameter estimation of BPSK-LFM combined modulation

NASA Astrophysics Data System (ADS)

Long, Chao; Zhang, Lin; Liu, Yu

2015-07-01

Intra-pulse analysis plays an important role in electronic warfare. Intra-pulse feature abstraction focuses on primary parameters such as instantaneous frequency, modulation, and symbol rate. In this paper, automatic modulation recognition and feature extraction for combined BPSK-LFM modulation signals based on decision theoretic approach is studied. The simulation results show good recognition effect and high estimation precision, and the system is easy to be realized.

Outdoor module testing and comparison of photovoltaic technologies

NASA Astrophysics Data System (ADS)

Fabick, L. B.; Rifai, R.; Mitchell, K.; Woolston, T.; Canale, J.

A comparison of outdoor test results for several module technologies is presented. The technologies include thin-film silicon:hydrogen alloys (TFS), TFS modules with semitransparent conductor back contacts, and CuInSe2 module prototypes. A method for calculating open-circuit voltage and fill-factor temperature coefficients is proposed. The method relies on the acquisition of large statistical data samples to average effects due to varying insolation level.

Wave Tank Studies of Strong Modulation of Wind Ripples Due To Long Waves

NASA Astrophysics Data System (ADS)

Ermakov, S.; Sergievskaya, I.; Shchegolkov, Yu.

Modulation of wind capillary-gravity ripples due to long waves has been studied in wave tank experiment at low wind speeds using Ka-band radar. The experiments were carried out both for clean water and the water surface covered with surfactant films. It is obtained that the modulation of radar signals is quite strong and can increase with surfactant concentration and fetch. It is shown that the hydrodynamic Modulation Transfer Function (MTF) calculated for free wind ripples and taking into account the kinematic (straining) effect, variations of the wind stress and variations of surfactant concentration strongly underestimates experimental MTF-values. The effect of strong modulation is assumed to be connected with nonlinear harmonics of longer dm-cm- scale waves - bound waves ("parasitic ripples"). The intensity of bound waves depends strongly on the amplitude of decimetre-scale waves, therefore even weak modulation of the dm-scale waves due to long waves results to strong ("cascade") modulation of bound waves. Modulation of the system of "free/bound waves" is estimated using results of wave tank studies of bound waves generation and is shown to be in quali- tative agreement with experiment. This work was supported by MOD, UK via DERA Winfrith (Project ISTC 1774P) and by RFBR (Project 02-05-65102).

Role of density modulation in the spatially resolved dynamics of strongly confined liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saw, Shibu, E-mail: shibu.saw@sydney.edu.au; Dasgupta, Chandan, E-mail: cdgupta@physics.iisc.ernet.in

Confinement by walls usually produces a strong modulation in the density of dense liquids near the walls. Using molecular dynamics simulations, we examine the effects of the density modulation on the spatially resolved dynamics of a liquid confined between two parallel walls, using a resolution of a fraction of the interparticle distance in the liquid. The local dynamics is quantified by the relaxation time associated with the temporal autocorrelation function of the local density. We find that this local relaxation time varies in phase with the density modulation. The amplitude of the spatial modulation of the relaxation time can bemore » quite large, depending on the characteristics of the wall and thermodynamic parameters of the liquid. To disentangle the effects of confinement and density modulation on the spatially resolved dynamics, we compare the dynamics of a confined liquid with that of an unconfined one in which a similar density modulation is induced by an external potential. We find several differences indicating that density modulation alone cannot account for all the features seen in the spatially resolved dynamics of confined liquids. We also examine how the dynamics near a wall depends on the separation between the two walls and show that the features seen in our simulations persist in the limit of large wall separation.« less

Entropy-based divergent and convergent modular pattern reveals additive and synergistic anticerebral ischemia mechanisms

PubMed Central

Yu, Yanan; Zhang, Xiaoxu; Li, Bing; Zhang, Yingying; Liu, Jun; Li, Haixia; Chen, Yinying; Wang, Pengqian; Kang, Ruixia; Wu, Hongli

2016-01-01

Module-based network analysis of diverse pharmacological mechanisms is critical to systematically understand combination therapies and disease outcomes. We first constructed drug-target ischemic networks in baicalin, jasminoidin, ursodeoxycholic acid, and their combinations baicalin and jasminoidin as well as jasminoidin and ursodeoxycholic acid groups and identified modules using the entropy-based clustering algorithm. The modules 11, 7, 4, 8 and 3 were identified as baicalin, jasminoidin, ursodeoxycholic acid, baicalin and jasminoidin and jasminoidin and ursodeoxycholic acid-emerged responsive modules, while 12, 8, 15, 17 and 9 were identified as disappeared responsive modules based on variation of topological similarity, respectively. No overlapping differential biological processes were enriched between baicalin and jasminoidin and jasminoidin and ursodeoxycholic acid pure emerged responsive modules, but two were enriched by their co-disappeared responsive modules including nucleotide-excision repair and epithelial structure maintenance. We found an additive effect of baicalin and jasminoidin in a divergent pattern and a synergistic effect of jasminoidin and ursodeoxycholic acid in a convergent pattern on “central hit strategy” of regulating inflammation against cerebral ischemia. The proposed module-based approach may provide us a holistic view to understand multiple pharmacological mechanisms associated with differential phenotypes from the standpoint of modular pharmacology. PMID:27480252

Oxytocin receptor gene polymorphism modulates the effects of social support on heart rate variability

PubMed Central

Kanthak, Magdalena K.; Chen, Frances S.; Kumsta, Robert; Hill, LaBarron K.; Thayer, Julian F.; Heinrichs, Markus

2017-01-01

A large body of empirical research has demonstrated stress-buffering effects of social support. However, recent studies suggest that genetic variation of the oxytocin system (specifically, a common single nucleotide polymorphism, rs53576, of the oxytocin receptor gene) modulates the efficacy of social support. The timing and neurobiological basis of this genetic modulation were investigated using a standardized, laboratory-based psychological stress procedure (Trier Social Stress Test for Groups, TSST-G). To index potential stress buffering effects of social support mediated by the oxytocin system, heart rate variability (HRV) was obtained before and during the TSST-G from 40 healthy participants. Results indicate that social support is associated with higher HRV only in G allele carriers. Specifically, social support increased heart rate variability during direct social interaction and only in individuals with at least one copy of the G allele of rs53576. These findings support the idea that the stress-attenuating effects of social support are modulated by genetic variation of the oxytocin system. PMID:26903384

Research on radiation characteristics of dipole antenna modulation by sub-wavelength inhomogeneous plasma layer

NASA Astrophysics Data System (ADS)

Kong, Fanrong; Chen, Peiqi; Nie, Qiuyue; Zhang, Xiaoning; Zhang, Zhen; Jiang, Binhao

2018-02-01

The modulation and enhancement effect of sub-wavelength plasma structures on compact antennas exhibits obvious technological advantage and considerable progress. In order to extend the availability of this technology under complex and actual environment with inhomogeneous plasma structure, a numerical simulation analysis based on finite element method has been conducted in this paper. The modulation function of the antenna radiation with sub-wavelength plasma layer located at different positions was investigated, and the inhomogeneous plasma layer with multiple electron density distribution profiles were employed to explore the effect of plasma density distribution on the antenna radiation. It has been revealed that the optical near-field modulated distance and reduced plasma distribution are more beneficial to enhance the radiation. On the basis above, an application-focused research about communication through the plasma sheath surrounding a hypersonic vehicle has been carried out aiming at exploring an effective communication window. The relevant results devote guiding significance in the field of antenna radiation modulation and enhancement, as well as the development of communication technology in hypersonic flight.

A predictive analytic model for the solar modulation of cosmic rays

DOE PAGES

Cholis, Ilias; Hooper, Dan; Linden, Tim

2016-02-23

An important factor limiting our ability to understand the production and propagation of cosmic rays pertains to the effects of heliospheric forces, commonly known as solar modulation. The solar wind is capable of generating time- and charge-dependent effects on the spectrum and intensity of low-energy (≲10 GeV) cosmic rays reaching Earth. Previous analytic treatments of solar modulation have utilized the force-field approximation, in which a simple potential is adopted whose amplitude is selected to best fit the cosmic-ray data taken over a given period of time. Making use of recently available cosmic-ray data from the Voyager 1 spacecraft, along withmore » measurements of the heliospheric magnetic field and solar wind, we construct a time-, charge- and rigidity-dependent model of solar modulation that can be directly compared to data from a variety of cosmic-ray experiments. Here, we provide a simple analytic formula that can be easily utilized in a variety of applications, allowing us to better predict the effects of solar modulation and reduce the number of free parameters involved in cosmic-ray propagation models.« less

Bandwidth tunable microwave photonic filter based on digital and analog modulation

NASA Astrophysics Data System (ADS)

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

2018-05-01

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

Ultracompact electro-optic phase modulator based on III-V-on-silicon microdisk resonator.

PubMed

Lloret, J; Kumar, R; Sales, S; Ramos, F; Morthier, G; Mechet, P; Spuesens, T; Van Thourhout, D; Olivier, N; Fédéli, J-M; Capmany, J

2012-06-15

A novel ultracompact electro-optic phase modulator based on a single 9 μm-diameter III-V microdisk resonator heterogeneously integrated on and coupled to a nanophotonic waveguide is presented. Modulation is enabled by effective index modification through carrier injection. Proof-of-concept implementation involving binary phase shift keying modulation format is assembled. A power imbalance of ∼0.6  dB between both symbols and a modulation rate up to 1.8 Gbps are demonstrated without using any special driving technique.

Optimization of coherent optical OFDM transmitter using DP-IQ modulator with nonlinear response

NASA Astrophysics Data System (ADS)

Chang, Sun Hyok; Kang, Hun-Sik; Moon, Sang-Rok; Lee, Joon Ki

2016-07-01

In this paper, we investigate the performance of dual polarization orthogonal frequency division multiplexing (DP-OFDM) signal generation when the signal is generated by a DP-IQ optical modulator. The DP-IQ optical modulator is made of four parallel Mach-Zehnder modulators (MZMs) which have nonlinear responses and limited extinction ratios. We analyze the effects of the MZM in the DP-OFDM signal generation by numerical simulation. The operating conditions of the DP-IQ modulator are optimized to have the best performance of the DP-OFDM signal.

Modulation bandwidth enhancement for coupled twin-square microcavity lasers.

PubMed

Xiao, Zhi-Xiong; Huang, Yong-Zhen; Yang, Yue-De; Tang, Min; Xiao, Jin-Long

2017-08-15

Modulation bandwidth enhancements are investigated for coupled twin-square microcavity lasers due to photon-photon resonance effect. For a coupled twin-square microcavity laser with the square side length of 20 μm, we demonstrate the increase of 3-dB modulation bandwidth from 9.6 GHz to 19.5 GHz, by adjusting the resonance mode wavelength interval between two square microcavities. The enhanced modulation bandwidth is explained by rate equation analysis, and numerical simulations are conducted for large signal modulation with improved eye-diagrams at 40 Gbit/s.

Handheld portable real-time tracking and communications device

DOEpatents

Wiseman, James M [Albuquerque, NM; Riblett, Jr., Loren E.; Green, Karl L [Albuquerque, NM; Hunter, John A [Albuquerque, NM; Cook, III, Robert N.; Stevens, James R [Arlington, VA

2012-05-22

Portable handheld real-time tracking and communications devices include; a controller module, communications module including global positioning and mesh network radio module, data transfer and storage module, and a user interface module enclosed in a water-resistant enclosure. Real-time tracking and communications devices can be used by protective force, security and first responder personnel to provide situational awareness allowing for enhance coordination and effectiveness in rapid response situations. Such devices communicate to other authorized devices via mobile ad-hoc wireless networks, and do not require fixed infrastructure for their operation.

Tuning of Human Modulation Filters Is Carrier-Frequency Dependent

PubMed Central

Simpson, Andrew J. R.; Reiss, Joshua D.; McAlpine, David

2013-01-01

Recent studies employing speech stimuli to investigate ‘cocktail-party’ listening have focused on entrainment of cortical activity to modulations at syllabic (5 Hz) and phonemic (20 Hz) rates. The data suggest that cortical modulation filters (CMFs) are dependent on the sound-frequency channel in which modulations are conveyed, potentially underpinning a strategy for separating speech from background noise. Here, we characterize modulation filters in human listeners using a novel behavioral method. Within an ‘inverted’ adaptive forced-choice increment detection task, listening level was varied whilst contrast was held constant for ramped increments with effective modulation rates between 0.5 and 33 Hz. Our data suggest that modulation filters are tonotopically organized (i.e., vary along the primary, frequency-organized, dimension). This suggests that the human auditory system is optimized to track rapid (phonemic) modulations at high sound-frequencies and slow (prosodic/syllabic) modulations at low frequencies. PMID:24009759

Effective connectivity during processing of facial affect: evidence for multiple parallel pathways.

PubMed

Dima, Danai; Stephan, Klaas E; Roiser, Jonathan P; Friston, Karl J; Frangou, Sophia

2011-10-05

The perception of facial affect engages a distributed cortical network. We used functional magnetic resonance imaging and dynamic causal modeling to characterize effective connectivity during explicit (conscious) categorization of affective stimuli in the human brain. Specifically, we examined the modulation of connectivity from posterior regions of the face-processing network to the lateral ventral prefrontal cortex (VPFC) during affective categorization and we tested for a potential role of the amygdala (AMG) in mediating this modulation. We found that explicit processing of facial affect led to prominent modulation (increase) in the effective connectivity from the inferior occipital gyrus (IOG) to the VPFC, while there was less evidence for modulation of the afferent connections from fusiform gyrus and AMG to VPFC. More specifically, the forward connection from IOG to the VPFC exhibited a selective increase under anger (as opposed to fear or sadness). Furthermore, Bayesian model comparison suggested that the modulation of afferent connections to the VPFC was mediated directly by facial affect, as opposed to an indirect modulation mediated by the AMG. Our results thus suggest that affective information is conveyed to the VPFC along multiple parallel pathways and that AMG activity is not sufficient to account for the gating of information transfer to the VPFC during explicit emotional processing.

Reducing Operating Temperature in Photovoltaic Modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silverman, Timothy J.; Deceglie, Michael G.; Subedi, Indra

Reducing the operating temperature of photovoltaic modules increases their efficiency and lifetime. This can be achieved by reducing the production of waste heat or by improving the rejection of waste heat. We tested, using a combination of simulation and experiment, several thermal modifications in each category. To predict operating temperature and energy yield changes in response to changes to the module, we implemented a physics-based transient simulation framework based almost entirely on measured properties. The most effective thermal modifications reduced the production of waste heat by reflecting unusable light from the cell or the module. Consistent with previous results andmore » verified in this work through year-long simulations, the ideal reflector resulted in an annual irradiance-weighted temperature reduction of 3.8 K for crystalline silicon (c-Si). Our results illustrate that more realistic reflector concepts must balance detrimental optical effects with the intended thermal effects to realize the optimal energy production advantage. Methods improving thermal conductivity or back-side emissivity showed only modest improvements of less than 1 K. We also studied a GaAs module, which uses high-efficiency and high-subbandgap reflectivity to operate at an annual irradiance-weighted temperature 12 K cooler than that of a c-Si module under the same conditions.« less

Reducing Operating Temperature in Photovoltaic Modules

DOE PAGES

Silverman, Timothy J.; Deceglie, Michael G.; Subedi, Indra; ...

2018-01-09

Reducing the operating temperature of photovoltaic modules increases their efficiency and lifetime. This can be achieved by reducing the production of waste heat or by improving the rejection of waste heat. We tested, using a combination of simulation and experiment, several thermal modifications in each category. To predict operating temperature and energy yield changes in response to changes to the module, we implemented a physics-based transient simulation framework based almost entirely on measured properties. The most effective thermal modifications reduced the production of waste heat by reflecting unusable light from the cell or the module. Consistent with previous results andmore » verified in this work through year-long simulations, the ideal reflector resulted in an annual irradiance-weighted temperature reduction of 3.8 K for crystalline silicon (c-Si). Our results illustrate that more realistic reflector concepts must balance detrimental optical effects with the intended thermal effects to realize the optimal energy production advantage. Methods improving thermal conductivity or back-side emissivity showed only modest improvements of less than 1 K. We also studied a GaAs module, which uses high-efficiency and high-subbandgap reflectivity to operate at an annual irradiance-weighted temperature 12 K cooler than that of a c-Si module under the same conditions.« less

Modulation of acetylcholine release from rat striatal slices by the GABA/benzodiazepine receptor complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Supavilai, P.; Karobath, M.

1985-02-04

GABA, THIP and muscimol enhance spontaneous and inhibit electrically induced release of tritium labelled compounds from rat striatal slices which have been pre-labelled with /sup 3/H-choline. Baclofen is inactive in this model. Muscimol can inhibit electrically induced release of tritiated material by approximately 75% with half maximal effects at 2 ..mu..M. The response to muscimol can be blocked by the GABA antagonists bicuculline methobromide, picrotoxin, anisatin, R 5135 and CPTBO (cyclopentylbicyclophosphate). Drugs which act on the benzodiazepine receptor (BR) require the presence of muscimol to be effective and they modulate the effects of muscimol in a bidirectional manner. Thus BRmore » agonists enhance and inverse BR agonists attenuate the inhibitory effects of muscimol on electrically induced release. Ro15-1788, a BR antagonist, does not modulate the inhibitory effects of muscimol but antagonizes the actions of clonazepam, a BR agonist, and of DMCM, an inverse BR agonist. These results demonstrate that a GABA/benzodiazepine receptor complex can modulate acetylcholine release from rat striatal slices in vitro. 24 references, 3 figures, 5 table.« less

Effects of neuronal nicotinic acetylcholine receptor allosteric modulators in animal behavior studies

PubMed Central

Pandya, Anshul. A.; Yakel, Jerrel L.

2013-01-01

Nicotinic acetylcholine receptors (nAChRs) are ligand-gated cation-conducting transmembrane channels from the cys-loop receptor superfamily. The neuronal subtypes of these receptors (e.g. the α7 and α4β2 subtypes) are involved in neurobehavioral processes such as anxiety, the central processing of pain, food intake, nicotine seeking behavior, and a number of cognitive functions like learning and memory. Neuronal nAChR dysfunction is involved in the pathophysiology of many neurological disorders, and behavioral studies in animals are useful models to assess the effects of compounds that act on these receptors. Allosteric modulators are ligands that bind to the receptors at sites other than the orthosteric site where acetylcholine, the endogenous agonist for the nAChRs, binds. While conventional ligands for the neuronal nAChRs have been studied for their behavioral effects in animals, allosteric modulators for these receptors have only recently gained attention, and research on their behavioral effects is growing rapidly. Here we will discuss the behavioral effects of allosteric modulators of the neuronal nAChRs. PMID:23732296

Module Eleven: Capacitance; Basic Electricity and Electronics Individualized Learning System.

ERIC Educational Resources Information Center

Bureau of Naval Personnel, Washington, DC.

In this module the student will learn about another circuit quantity, capacitance, and discover the effects of this component on circuit current, voltage, and power. The module is divided into seven lessons: the capacitor, theory of capacitance, total capacitance, RC (resistive-capacitive circuit) time constant, capacitive reactance, phase and…

A Continuing Education Program on Attention Deficit/Hyperactivity Disorder.

ERIC Educational Resources Information Center

Kallas, Anmarie; Reeve, Ron E.; Welch, Ann B.; Wright, James V.

1997-01-01

Describes the four modules of a project for enhancing the knowledge and skills of educators to better serve children with attention deficits, and the inservice personnel-preparation program based on these modules. Modules focus on characteristics and identification, model school programs, effective classroom interventions, and policy and…

Research Report for the Organizing for Diversity Project.

ERIC Educational Resources Information Center

Betsinger, Alicia M.; Garcia, Shernaz B.; Guerra, Patricia L.

This report describes the Organizing for Diversity Project, which generated professional development modules to prepare teachers to work more effectively with diverse students. Prototype modules were developed in collaboration with teacher volunteers, then field tested. The final 11 modules, which included 33 hours of training, were designed for…

Module Eight: Induction; Basic Electricity and Electronics Individualized Learning System.

ERIC Educational Resources Information Center

Bureau of Naval Personnel, Washington, DC.

The module covers in greater depth electromagnetic induction, its effects, and how it is used to advantage in electrical circuits; and the physical components, called inductors, designed to take advantage of the phenomenon of electromagnetic induction. This module is divided into four lessons: electromagnetism; inductors and flux density, inducing…

Development and Evaluation of an Interactive Internet-Based Pharmacokinetic Teaching Module.

ERIC Educational Resources Information Center

Hedaya, Mohsen A.

1998-01-01

Describes an Internet-based, interactive, learner-centered, asynchronous instructional module for pharmacokinetics that requires minimal computer knowledge to operate. Main components are concept presentation, a simulation exercise, and self-assessment questions. The module has been found effective in teaching the steady state concept at the…

Dynamic e-Learning Modules for Student Lecture Preparation

ERIC Educational Resources Information Center

McIntyre, Timothy; Wegener, Margaret; McGrath, Dominic

2018-01-01

We have developed and demonstrated the effectiveness of a set of online interactive learning modules to accompany physics courses at first- and second-year university levels. Students access the modules prior to attending lectures to familiarize themselves with content which is then discussed and reaffirmed in class. Student surveys and access…

A model of clearance rate regulation in mussels

NASA Astrophysics Data System (ADS)

Fréchette, Marcel

2012-10-01

Clearance rate regulation has been modelled as an instantaneous response to food availability, independent of the internal state of the animals. This view is incompatible with latent effects during ontogeny and phenotypic flexibility in clearance rate. Internal-state regulation of clearance rate is required to account for these patterns. Here I develop a model of internal-state based regulation of clearance rate. External factors such as suspended sediments are included in the model. To assess the relative merits of instantaneous regulation and internal-state regulation, I modelled blue mussel clearance rate and growth using a DEB model. In the usual standard feeding module, feeding is governed by a Holling's Type II response to food concentration. In the internal-state feeding module, gill ciliary activity and thus clearance rate are driven by internal reserve level. Factors such as suspended sediments were not included in the simulations. The two feeding modules were compared on the basis of their ability to capture the impact of latent effects, of environmental heterogeneity in food abundance and of physiological flexibility on clearance rate and individual growth. The Holling feeding module was unable to capture the effect of any of these sources of variability. In contrast, the internal-state feeding module did so without any modification or ad hoc calibration. Latent effects, however, appeared transient. With simple annual variability in temperature and food concentration, the relationship between clearance rate and food availability predicted by the internal-state feeding module was quite similar to that observed in Norwegian fjords. I conclude that in contrast with the usual Holling feeding module, internal-state regulation of clearance rate is consistent with well-documented growth and clearance rate patterns.

Mitigation of PID in commercial PV modules using current interruption method

NASA Astrophysics Data System (ADS)

Bora, Birinchi; Oh, Jaewon; Tatapudi, Sai; Sastry, Oruganty S.; Kumar, Rajesh; Prasad, Basudev; Tamizhmani, Govindasamy

2017-08-01

Potential-induced degradation (PID) is known to have a very severe effect on the reliability of PV modules. PID is caused due to the leakage of current from the cell circuit to the grounded frame under humid conditions of high voltage photovoltaic (PV) systems. There are multiple paths for the current leakage. The most dominant leakage path is from the cell to the frame through encapsulant, glass bulk and glass surface. This dominant path can be prevented by interrupting the electrical conductivity at the glass surface. In our previous works related to this topic, we demonstrated the effectiveness of glass surface conductivity interruption technique using one-cell PV coupons. In this work, we demonstrate the effectiveness of this technique using a full size commercial module susceptible to PID. The interruption of surface conductivity of the commercial module was achieved by attaching a narrow, thin flexible glass strips, from Corning, called Willow Glass on the glass surface along the inner edges of the frame. The flexible glass strip was attached to the module glass surface by heating the glass strip with an ionomer adhesive underneath using a handheld heat gun. The PID stress test was performed at 60°C and 85% RH for 96 hours at -600 V. Pre- and post-PID characterizations including I-V and electroluminescence were carried out to determine the performance loss and affected cell areas. This work demonstrates that the PID issue can be effectively addressed by using this current interruption technique. An important benefit of this approach is that this interruption technique can be applied after manufacturing the modules and after installing the modules in the field as well.

Breathing frequency-independent effect of Tai Chi Chuan on autonomic modulation.

PubMed

Lu, Wan-An; Kuo, Cheng-Deng

2014-04-01

This study investigates the breathing frequency (BF)-independent effect of Tai Chi Chuan (TCC) on autonomic nervous modulation in TCC practitioners. Twenty-five TCC practitioners and 25 sedentary normal controls were recruited. The stationary heart rate variability (HRV) measures of TCC practitioners and controls were compared. The same HRV measures in TCC practitioners and among the controls, TCC practitioners before TCC and TCC practitioners 30 min after TCC were compared. In TCC practitioners, the BF, normalized high-frequency power (nHFP), and normalized very low-frequency power were significantly increased, while the normalized low-frequency power (nLFP) was significantly decreased 30 min after TCC. The BF correlated significantly and negatively with heart rate (HR), nHFP and nLFP, and correlated significantly and positively with mean RR interval (MnRR) before TCC in TCC practitioners. A slower BF is associated with a higher HR, a greater vagal modulation, and a greater combined sympatho-vagal modulation before TCC. To remove the effect of BF on HRV measures, new indices such as HR*BF, nHFP*BF, nLFP*BF, and MnRR/BF were introduced for comparison among the controls, TCC practitioners before TCC, and TCC practitioners 30 min after TCC. Thirty minutes after TCC, the MnRR/BF of TCC practitioner was smaller whereas HR*BF and nHFP*BF were greater than those before TCC. The BF-independent effects of TCC on the autonomic nervous modulation of TCC practitioners are an increase in vagal modulation and HR, and a decrease in mean RR interval. The mechanism underlying the parallel increase in HR and vagal modulation in TCC practitioners is not understood yet at present.

ETF system code: composition and applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reid, R.L.; Wu, K.F.

1980-01-01

A computer code has been developed for application to ETF tokamak system and conceptual design studies. The code determines cost, performance, configuration, and technology requirements as a function of tokamak parameters. The ETF code is structured in a modular fashion in order to allow independent modeling of each major tokamak component. The primary benefit of modularization is that it allows updating of a component module, such as the TF coil module, without disturbing the remainder of the system code as long as the input/output to the modules remains unchanged. The modules may be run independently to perform specific design studies,more » such as determining the effect of allowable strain on TF coil structural requirements, or the modules may be executed together as a system to determine global effects, such as defining the impact of aspect ratio on the entire tokamak system.« less

Tuned Normalization Explains the Size of Attention Modulations

PubMed Central

Ni, Amy M.; Ray, Supratim; Maunsell, John H. R.

2012-01-01

SUMMARY The effect of attention on firing rates varies considerably within a single cortical area. The firing rate of some neurons is greatly modulated by attention while others are hardly affected. The reason for this variability across neurons is unknown. We found that the variability in attention modulation across neurons in area MT of macaques can be well explained by variability in the strength of tuned normalization across neurons. The presence of tuned normalization also explains a striking asymmetry in attention effects within neurons: when two stimuli are in a neuron’s receptive field, directing attention to the preferred stimulus modulates firing rates more than directing attention to the non-preferred stimulus. These findings show that much of the neuron-to-neuron variability in modulation of responses by attention depends on variability in the way the neurons process multiple stimuli, rather than differences in the influence of top-down signals related to attention. PMID:22365552

Histaminergic Mechanisms for Modulation of Memory Systems

PubMed Central

Köhler, Cristiano André; da Silva, Weber Cláudio; Benetti, Fernando; Bonini, Juliana Sartori

2011-01-01

Encoding for several memory types requires neural changes and the activity of distinct regions across the brain. These areas receive broad projections originating in nuclei located in the brainstem which are capable of modulating the activity of a particular area. The histaminergic system is one of the major modulatory systems, and it regulates basic homeostatic and higher functions including arousal, circadian, and feeding rhythms, and cognition. There is now evidence that histamine can modulate learning in different types of behavioral tasks, but the exact course of modulation and its mechanisms are controversial. In the present paper we review the involvement of the histaminergic system and the effects histaminergic receptor agonists/antagonists have on the performance of tasks associated with the main memory types as well as evidence provided by studies with knockout models. Thus, we aim to summarize the possible effects histamine has on modulation of circuits involved in memory formation. PMID:21876818

Effects of outdoor exposure on solar cell modules in the ERDA/NASA Lewis Research Center Systems Test Facility

NASA Technical Reports Server (NTRS)

Weinberg, I.; Curtis, H. B.; Forestieri, A. F.

1977-01-01

The effects of outdoor exposure were determined by comparing standard I-V data obtained for the as-received modules with similar data obtained after removal from the field and cleaning with detergent solution. All modules measured in this way exhibited nonrecoverable degradation in P sub maximum varying from 4 to 7 percent. One module exposed for 41 days exhibited partial cell discoloration, loss of front surface metallization over the discolored portion, and a decrease in P sub maximum of 7 percent, tentatively attributed to cell damage. Measurements before and after cleaning showed a recoverable degradation due to dirt accumulation. This recoverable loss in power was 11 percent after 245 days in the field for one brand of module, 6 percent after 48 days for another brand, and 4 1/2 percent for the third brand.

Tuned normalization explains the size of attention modulations.

PubMed

Ni, Amy M; Ray, Supratim; Maunsell, John H R

2012-02-23

The effect of attention on firing rates varies considerably within a single cortical area. The firing rate of some neurons is greatly modulated by attention while others are hardly affected. The reason for this variability across neurons is unknown. We found that the variability in attention modulation across neurons in area MT of macaques can be well explained by variability in the strength of tuned normalization across neurons. The presence of tuned normalization also explains a striking asymmetry in attention effects within neurons: when two stimuli are in a neuron's receptive field, directing attention to the preferred stimulus modulates firing rates more than directing attention to the nonpreferred stimulus. These findings show that much of the neuron-to-neuron variability in modulation of responses by attention depends on variability in the way the neurons process multiple stimuli, rather than differences in the influence of top-down signals related to attention. Copyright © 2012 Elsevier Inc. All rights reserved.

Self-demodulation of amplitude-modulated signal components in amplitude-modulated bone-conducted ultrasonic hearing

NASA Astrophysics Data System (ADS)

Ito, Kazuhito; Nakagawa, Seiji

2015-07-01

A novel hearing aid system utilizing amplitude-modulated bone-conducted ultrasound (AM-BCU) is being developed for use by profoundly deaf people. However, there is a lack of research on the acoustic aspects of AM-BCU hearing. In this study, acoustic fields in the ear canal under AM-BCU stimulation were examined with respect to the self-demodulation effect of amplitude-modulated signal components generated in the ear canal. We found self-demodulated signals with an audible sound pressure level related to the amplitude-modulated signal components of bone-conducted ultrasonic stimulation. In addition, the increases in the self-demodulated signal levels at low frequencies in the ear canal after occluding the ear canal opening, i.e., the positive occlusion effect, indicate the existence of a pathway by which the self-demodulated signals pass through the aural cartilage and soft tissue, and radiate into the ear canal.

Hybrid metasurface for ultra-broadband terahertz modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heyes, Jane E.; Withayachumnankul, Withawat; Grady, Nathaniel K.

2014-11-05

We demonstrate an ultra-broadband free-space terahertz modulator based on a semiconductor-integrated metasurface. The modulator is made of a planar array of metal cut-wires on a silicon-on-sapphire substrate, where the silicon layer functions as photoconductive switches. Without external excitation, the cut-wire array exhibits a Lorentzian resonant response with a transmission passband spanning dc up to the fundamental dipole resonance above 2 THz. Under photoexcitation with 1.55 eV near-infrared light, the silicon regions in the cut-wire gaps become highly conductive, causing a transition of the resonant metasurface to a wire grating with a Drude response. In effect, the low-frequency passband below 2more » THz evolves into a stopband for the incident terahertz waves. Experimental validations confirm a bandwidth of at least 100%, spanning 0.5 to 1.5 THz with -10 dB modulation depth. This modulation depth is far superior to -5 dB achievable from a plain silicon-on-sapphire substrate with effectively 25 times higher pumping energy. The proposed concept of ultra-broadband metasurface modulator can be readily extended to electrically controlled terahertz wave modulation.« less

Modulation instability and dissipative rogue waves in ion-beam plasma: Roles of ionization, recombination, and electron attachment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Shimin, E-mail: gsm861@126.com; Mei, Liquan, E-mail: lqmei@mail.xjtu.edu.cn

The amplitude modulation of ion-acoustic waves is investigated in an unmagnetized plasma containing positive ions, negative ions, and electrons obeying a kappa-type distribution that is penetrated by a positive ion beam. By considering dissipative mechanisms, including ionization, negative-positive ion recombination, and electron attachment, we introduce a comprehensive model for the plasma with the effects of sources and sinks. Via reductive perturbation theory, the modified nonlinear Schrödinger equation with a dissipative term is derived to govern the dynamics of the modulated waves. The effect of the plasma parameters on the modulation instability criterion for the modified nonlinear Schrödinger equation is numericallymore » investigated in detail. Within the unstable region, first- and second-order dissipative ion-acoustic rogue waves are present. The effect of the plasma parameters on the characteristics of the dissipative rogue waves is also discussed.« less

[Design of modulating intermediate frequency electrotherapy system based on microcontroller unit].

PubMed

Yu, Xuefei; Liu, Xianfeng; Peng, Daming

2010-12-01

This article is devoted to the design of a system for modulating intermediate frequency electrotherapy waveform output. Prescriptions with different output waveform combinations were produced using microcontroller unit (MCU). The rich output waveforms effectively improve tolerance of human adaptability and achieve a therapeutic effect.

10 CFR 431.226 - Energy conservation standards and their effective dates.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Energy conservation standards and their effective dates. 431.226 Section 431.226 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Traffic Signal Modules and Pedestrian Modules Energy...

10 CFR 431.226 - Energy conservation standards and their effective dates.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 3 2011-01-01 2011-01-01 false Energy conservation standards and their effective dates. 431.226 Section 431.226 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Traffic Signal Modules and Pedestrian Modules Energy...

10 CFR 431.226 - Energy conservation standards and their effective dates.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Energy conservation standards and their effective dates. 431.226 Section 431.226 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Traffic Signal Modules and Pedestrian Modules Energy...

10 CFR 431.226 - Energy conservation standards and their effective dates.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Energy conservation standards and their effective dates. 431.226 Section 431.226 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Traffic Signal Modules and Pedestrian Modules Energy...

10 CFR 431.226 - Energy conservation standards and their effective dates.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Energy conservation standards and their effective dates. 431.226 Section 431.226 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Traffic Signal Modules and Pedestrian Modules Energy...

Development of Ethnoscience Approach in The Module Theme Substance Additives to Improve the Cognitive Learning Outcome and Student’s entrepreneurship

NASA Astrophysics Data System (ADS)

Sudarmin; Febu, R.; Nuswowati, M.; Sumarni, W.

2017-04-01

Ethnoscience approach is an interesting research today. The purpose of this research is to develop approaches ethnoscience and modules ethnoscience theme additives based ethnoscience; as well as assess the feasibility and effectiveness of module theme additives based ethnoscience to improve learning outcomes and the entrepreneurial character of students. This type of research is the Research and Development (R & D). In this research consist of four stages, namely define, design, development and implementation. The subjects of this study were students of the School of MTs Maarif NU Brebes. Data were analyzed by descriptive qualitative and quantitative. The results showed that ethnoscience approach and the module theme substance additives used declared worthy of National Education Standards Agency (BNSP) with an average percentage of validation on the feasibility aspect of the content, language feasibility, and feasibility of presenting respectively for 94.3%, 86 % and 92% and a very decent entry criteria. The effect of the application modules substance additive based ethnoscience can improve on the cognitive learning classical amounted to 90.63%, and increased learning outcomes category was based on the scores of N-gain. Influence ethnoscience approach application and module theme substances additives based ethnoscience able to improve the entrepreneurial character of students. Based on the results of this study concluded that the ethnoscience approach and module theme substance additives based ethnoscience effective to improve learning outcomes and students’ entrepreneurship.

N-Scan®: New Vibro-Modulation System for Crack Detection, Monitoring and Characterization

NASA Astrophysics Data System (ADS)

Zagrai, Andrei; Donskoy, Dimitri; Lottiaux, Jean-Louis

2004-02-01

In recent years, an innovative vibro-modulation technique has been introduced for the detection of contact-type interfaces such as cracks, debondings, and delaminations. The technique utilizes the effect of nonlinear interaction of ultrasound and vibrations at the interface of the defect. Vibration varies the contact area of the interface, modulating a passing ultrasonic wave. The modulation manifests itself as additional side-band spectral components with the combination frequencies in the spectrum of the received signal. The presence of these components allows for the detection and differentiation of the contact-type defects from other structural and material inhomogeneities. The vibro-modulation technique has been implemented in the N-SCAN® damage detection system providing a cost effective solution for the complex NDT problems. N-SCAN® proved to be very effective for damage detection and characterization in structures and structural components of simple and complex geometries made of steel, aluminum, composites, and other materials. Examples include 24 foot-long gun barrels, stainless steel pipes used in nuclear power plants, aluminum automotive parts, steel train couplers, etc. This paper describes the basic principles of the nonlinear vibro-modulation NDE technique, some theoretical background for nonlinear interaction, and justification of signal processing algorithms. The laboratory experiment is presented for a set of specimens with the calibrated cracks and the quantitative characterization of fatigue damage is given in terms of a modulation index. The paper also discusses examples of practical implementation and application of the technique.

Vestibular Activation Differentially Modulates Human Early Visual Cortex and V5/MT Excitability and Response Entropy

PubMed Central

Guzman-Lopez, Jessica; Arshad, Qadeer; Schultz, Simon R; Walsh, Vincent; Yousif, Nada

2013-01-01

Head movement imposes the additional burdens on the visual system of maintaining visual acuity and determining the origin of retinal image motion (i.e., self-motion vs. object-motion). Although maintaining visual acuity during self-motion is effected by minimizing retinal slip via the brainstem vestibular-ocular reflex, higher order visuovestibular mechanisms also contribute. Disambiguating self-motion versus object-motion also invokes higher order mechanisms, and a cortical visuovestibular reciprocal antagonism is propounded. Hence, one prediction is of a vestibular modulation of visual cortical excitability and indirect measures have variously suggested none, focal or global effects of activation or suppression in human visual cortex. Using transcranial magnetic stimulation-induced phosphenes to probe cortical excitability, we observed decreased V5/MT excitability versus increased early visual cortex (EVC) excitability, during vestibular activation. In order to exclude nonspecific effects (e.g., arousal) on cortical excitability, response specificity was assessed using information theory, specifically response entropy. Vestibular activation significantly modulated phosphene response entropy for V5/MT but not EVC, implying a specific vestibular effect on V5/MT responses. This is the first demonstration that vestibular activation modulates human visual cortex excitability. Furthermore, using information theory, not previously used in phosphene response analysis, we could distinguish between a specific vestibular modulation of V5/MT excitability from a nonspecific effect at EVC. PMID:22291031

Wave-Coupled Millimeter-Wave Electro-Optic Techniques

DTIC Science & Technology

2001-03-01

This report details results on two antenna-coupled millimeter-wave electro - optic modulators, the slot-vee antenna-coupled modulator and a 94 GHz...study of the effects of velocity mismatch on linearized electro - optic modulators was made and the results published. A key result was that directional...drift in electro - optic modulators was made and protons were determined to be the cause. Several inventions were made to reduce or eliminate proton-caused bias drift.

A holistic view of crystalline silicon module reliability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanoka, J.I.

1995-11-01

Several aspects of module reliability are discussed, particularly with reference to the encapsulant and its interaction with the metallization and interconnection of a module. A need to look at the module as a whole single unit is stressed. Also, the issue of a slight light degradation effect in crystalline silicon cells is discussed. A model for this is mentioned and it may well be that polycrystalline cells with dislocations may have an advantage.

Frequency-Dependent Modulation of Dopamine Release by Nicotine and Dopamine D1 Receptor Ligands: An In Vitro Fast Cyclic Voltammetry Study in Rat Striatum.

PubMed

Goutier, W; Lowry, J P; McCreary, A C; O'Connor, J J

2016-05-01

Nicotine is a highly addictive drug and exerts this effect partially through the modulation of dopamine release and increasing extracellular dopamine in regions such as the brain reward systems. Nicotine acts in these regions on nicotinic acetylcholine receptors. The effect of nicotine on the frequency dependent modulation of dopamine release is well established and the purpose of this study was to investigate whether dopamine D1 receptor (D1R) ligands have an influence on this. Using fast cyclic voltammetry and rat corticostriatal slices, we show that D1R ligands are able to modulate the effect of nicotine on dopamine release. Nicotine (500 nM) induced a decrease in dopamine efflux at low frequency (single pulse or five pulses at 10 Hz) and an increase at high frequency (100 Hz) electrical field stimulation. The D1R agonist SKF-38393, whilst having no effect on dopamine release on its own or on the effect of nicotine upon multiple pulse evoked dopamine release, did significantly prevent and reverse the effect of nicotine on single pulse dopamine release. Interestingly similar results were obtained with the D1R antagonist SCH-23390. In this study we have demonstrated that the modulation of dopamine release by nicotine can be altered by D1R ligands, but only when evoked by single pulse stimulation, and are likely working via cholinergic interneuron driven dopamine release.

Instruction via Web-Based Modules in Early Childhood Personnel Preparation: A Mixed-Methods Study of Effectiveness and Learner Perspectives

ERIC Educational Resources Information Center

Hollingsworth, Heidi L.; Lim, Chih-Ing

2015-01-01

Effective personnel preparation is critical to the development of a high quality early childhood workforce that provides optimal care and education for young children. This mixed-methods study examined the effectiveness of, and learner perspectives on, instruction via web-based modules within face-to-face early childhood personnel preparation…

The Effects of Aggregation Method and Variations in the Performance of Individual Students on Degree Classifications in Modular Degree Courses.

ERIC Educational Resources Information Center

Simonite, Vanessa

2000-01-01

Considers implications of modularization of first degree courses in the United Kingdom, especially the effects of different systems for selecting and combining module marks on students' degree classifications. Discusses the effects of different systems of aggregation on student marks in different modules and ultimately on class placement and…

Instruction manual, Optical Effects Module, Model OEM

NASA Technical Reports Server (NTRS)

1975-01-01

The Optical Effects Module Model OEM-1, a laboratory prototype instrument designed for the automated measurement of radiation transmission and scattering through optical samples, is described. The system comprises two main components: the Optical Effects Module Enclosure (OEME) and the Optical Effects Module Electronic Controller and Processor (OEMCP). The OEM is designed for operation in the near UV at approximately 2540A, corresponding to the most intense spectral line activated by the mercury discharge lamp used for illumination. The radiation from this source is detected in transmission and reflection through a number of selectable samples. The basic objective of this operation is to monitor in real time the accretion of possible contamination on the surface of these samples. The optical samples are exposed outside of the OEME proper to define exposure conditions and to separate exposure and measurement environments. Changes in the transmissivity of the sample are attributable to surface contamination or to bulk effects due to radiation. Surface contamination will increase radiation scattering due to Rayleigh-Gans effect or to other phenomena, depending on the characteristics size of the particulate contaminants. Thus, also scattering from the samples becomes a part of the measurement program.

Outcome of chemotherapy counseling by pharmacists on psychological effects and self esteem among oncology patients in a Government Hospital in Malaysia.

PubMed

Ummavathy, P; Sherina, M S; Rampal, L; Siti Irma Fadhilah, I

2015-06-01

Chemotherapy is the most common form of treatment among cancer patients. It is also known to cause many physical and psychological side-effects. This study developed, implemented and evaluated the outcome of a chemotherapy counseling module among oncology patients by pharmacists based on their psychological effects (depression, anxiety) and selfesteem. A randomized, single blind, placebo controlled study was conducted among 162 patients undergoing chemotherapy in a government hospital in Malaysia. Counseling sessions were conducted using the 'Managing Patients on Chemotherapy' module for oncology patients undergoing chemotherapy at each treatment cycle. The outcome of repetitive chemotherapy counseling using the module was determined at baseline, first follow-up, second follow-up and third follow-up. The findings revealed that there was significant improvement in the intervention group as compared to the control group with large effect size on depression (p = 0.001, partial η(2) = 0.394), anxiety (p = 0.001, partial η(2) = 0.232) and self-esteem (p = 0.001, partial η(2) = 0.541). Repetitive counseling using the 'Managing Patients on Chemotherapy' module was found to be effective in improving psychological effects and self-esteem among patients undergoing chemotherapy.

Detection of a Novel Mechanism of Acousto-Optic Modulation of Incoherent Light

PubMed Central

Jarrett, Christopher W.; Caskey, Charles F.; Gore, John C.

2014-01-01

A novel form of acoustic modulation of light from an incoherent source has been detected in water as well as in turbid media. We demonstrate that patterns of modulated light intensity appear to propagate as the optical shadow of the density variations caused by ultrasound within an illuminated ultrasonic focal zone. This pattern differs from previous reports of acousto-optical interactions that produce diffraction effects that rely on phase shifts and changes in light directions caused by the acoustic modulation. Moreover, previous studies of acousto-optic interactions have mainly reported the effects of sound on coherent light sources via photon tagging, and/or the production of diffraction phenomena from phase effects that give rise to discrete sidebands. We aimed to assess whether the effects of ultrasound modulation of the intensity of light from an incoherent light source could be detected directly, and how the acoustically modulated (AOM) light signal depended on experimental parameters. Our observations suggest that ultrasound at moderate intensities can induce sufficiently large density variations within a uniform medium to cause measurable modulation of the intensity of an incoherent light source by absorption. Light passing through a region of high intensity ultrasound then produces a pattern that is the projection of the density variations within the region of their interaction. The patterns exhibit distinct maxima and minima that are observed at locations much different from those predicted by Raman-Nath, Bragg, or other diffraction theory. The observed patterns scaled appropriately with the geometrical magnification and sound wavelength. We conclude that these observed patterns are simple projections of the ultrasound induced density changes which cause spatial and temporal variations of the optical absorption within the illuminated sound field. These effects potentially provide a novel method for visualizing sound fields and may assist the interpretation of other hybrid imaging methods. PMID:25105880

Optical simulations for design, alignment, and performance prediction of silicon pore optics for the ATHENA x-ray telescope (Conference Presentation)

NASA Astrophysics Data System (ADS)

Spiga, D.; Della Monica Ferreira, D.; Shortt, B.; Bavdaz, M.; Bergback Knudsen, E.; Bianucci, G.; Christensen, F.; Civitani, M.; Collon, M.; Conconi, P.; Fransen, S.; Marioni, F.; Massahi, S.; Pareschi, G.; Salmaso, B.; Jegers, A. S.; Tayabaly, K.; Valsecchi, G.; Westergaard, N.; Wille, E.

2017-09-01

The ATHENA X-ray observatory is a large-class ESA approved mission, with launch scheduled in 2028. The technology of silicon pore optics (SPO) was selected as baseline to assemble ATHENA's optic with hundreds of mirror modules, obtained by stacking wedged and ribbed silicon wafer plates onto silicon mandrels to form the Wolter-I configuration. In the current configuration, the optical assembly has a 3 m diameter and a 2 m2 effective area at 1 keV, with a required angular resolution of 5 arcsec. The angular resolution that can be achieved is chiefly the combination of 1) the focal spot size determined by the pore diffraction, 2) the focus degradation caused by surface and profile errors, 3) the aberrations introduced by the misalignments between primary and secondary segments, 4) imperfections in the co-focality of the mirror modules in the optical assembly. A detailed simulation of these aspects is required in order to assess the fabrication and alignment tolerances; moreover, the achievable effective area and angular resolution depend on the mirror module design. Therefore, guaranteeing these optical performances requires: a fast design tool to find the most performing solution in terms of mirror module geometry and population, and an accurate point spread function simulation from local metrology and positioning information. In this paper, we present the results of simulations in the framework of ESA-financed projects (SIMPOSiuM, ASPHEA, SPIRIT), in preparation of the ATHENA X-ray telescope, analyzing the mentioned points: 1) we deal with a detailed description of diffractive effects in an SPO mirror module, 2) we show ray-tracing results including surface and profile defects of the reflective surfaces, 3) we assess the effective area and angular resolution degradation caused by alignment errors between SPO mirror module's segments, and 4) we simulate the effects of co-focality errors in X-rays and in the UV optical bench used to study the mirror module alignment and integration.

Surgeon-authored Virtual Laparoscopic Adrenalectomy Module is Judged Effective and Preferred over Traditional Teaching Tools

PubMed Central

Kurenov, Sergei; Cendan, Juan; Dindar, Sahel; Attwood, Kristopher; Hassett, James; Nawotniak, Ruth; Cherr, Gregory; Cance, William G.; Peters, Jörg

2018-01-01

Objective The study assesses user acceptance and effectiveness of a surgeon-authored virtual reality training module authored by surgeons using the Toolkit for Illustration Procedures in Surgery (TIPS). Methods Laparoscopic adrenalectomy was selected to test the TIPS framework on an unusual and complex procedure. No commercial simulation module exists to teach this procedure. A specialist surgeon authored the module, including force-feedback interactive simulation and designed a quiz to test knowledge of the key procedural steps. Five practicing surgeons with 15 to 24 years of experience peer-reviewed and tested the module. Fourteen residents and nine fellows trained with the module and answered the quiz, pre-use and post-use. Participants received an overview during Surgical Grand Rounds session and a 20-minute one- on-one tutorial followed by a 30 minute of instruction in addition to a force-feedback interactive simulation session. Additionally, in answering questionnaires, the trainees reflected on their learning experience and their experience with the TIPS framework. Results Correct quiz response rates on procedural steps improved significantly post-use over pre-use. In the questionnaire, 96% of the respondents stated that the TIPS module prepares them well or very well for the adrenalectomy, and 87% indicated that the module successfully teaches the steps of the procedure. All subjects indicated that they preferred the module compare to training using purely physical props, one-on-one teaching, medical atlases, and video recordings. Conclusions Improved quiz scores and endorsement by the participants of the TIPS adrenalectomy module establish the viability of surgeons authoring virtual reality training. PMID:27758896

Working with interpreters: an interactive Web-based learning module.

PubMed

Kalet, Adina; Gany, Francesca; Senter, Lindsay

2002-09-01

Medical students are presented with unique challenges when they care for patients with limited English proficiency. Students must learn a complex set of skills needed to care for patients across cultural and language barriers and to understand the impact of their own attitudes and beliefs about caring for these patients. We developed and piloted a multimedia interactive Web-based module aimed at teaching students effective strategies for working with interpreters and diverse patient populations, and at raising their awareness of important legal, ethical, and cultural issues. First the learner completes a 37-multiple-choice-question (MCQ) pre-test that assesses attitudes, factual knowledge, and ability to analyze written clinical scenarios relevant to the module's content. Learners are then shown a series of professionally produced video vignettes, which reflect diverse patient populations, interpreters, and effectiveness of interpretation strategies (e.g., a Russian-speaking woman with chest pain whose daughter interprets, a medical student interpreting for a Chinese-speaking man using herbal medication, a Haitian woman told of an abnormal mammogram through a trained simultaneous interpreter). In each case, learners submit short answers to on-screen questions analyzing the effectiveness of the interpretation strategies demonstrated. Immediate feedback is given comparing student responses with those of experts. At any time during the module, the learners may view video commentary by legal, ethics, and cultural experts, or access a glossary and Web site links. Students conclude the module by again taking the MCQ test. A final screen compares their pre- and post-MCQ test responses and shows best answers, allowing them to assess their learning. The learners also complete a survey, providing personal cultural information and feedback on the module. All 160 first-year medical students completed the module and evaluated its effectiveness this year. On average, students improved by 20% on the MCQ post-test and 86% of the students were satisfied with the learning experience and acquired new knowledge. As a result of their participation in the module, students examined their own cultural and linguistic backgrounds and made the following comments: "I am interested in exploring the way my own culture and cultural biases could impact my working with patients from other cultures"; "This module has opened my eyes to the fears and concerns of immigrants who do not speak English." Therefore, this pilot of the module effectively imparted guidelines for, and raised awareness of, medical interpreting. The most common critique of the module was that as a result of technical difficulties, it was time-consuming. A more rigorous evaluation is planned for the next academic year. We are also working to enrich and enhance the module for more experienced clinicians (GME and CME). As a complementary educational tool, the Internet has the advantages of allowing students to work at their own paces, view engaging video clips, and participate in interactive learning with immediate feedback and self-assessment.

Characterization of submillisecond response optical addressing phase modulator based on low light scattering polymer network liquid crystal

NASA Astrophysics Data System (ADS)

Xiangjie, Zhao; Cangli, Liu; Jiazhu, Duan; Dayong, Zhang; Yongquan, Luo

2015-01-01

Optically addressed conventional nematic liquid crystal spatial light modulator has attracted wide research interests. But the slow response speed limited its further application. In this paper, polymer network liquid crystal (PNLC) was proposed to replace the conventional nematic liquid crystal to enhance the response time to the order of submillisecond. The maximum light scattering of the employed PNLC was suppressed to be less than 2% at 1.064 μm by optimizing polymerization conditions and selecting large viscosity liquid crystal as solvent. The occurrence of phase ripple phenomenon due to electron diffusion and drift in photoconductor was found to deteriorate the phase modulation effect of the optical addressed PNLC phase modulator. The wavelength effect and AC voltage frequency effect on the on state dynamic response of phase change was investigated by experimental methods. These effects were interpreted by electron diffusion and drift theory based on the assumption that free electron was inhomogeneously distributed in accordance with the writing beam intensity distribution along the incident direction. The experimental results indicated that the phase ripple could be suppressed by optimizing the wavelength of the writing beam and the driving AC voltage frequency when varying the writing beam intensity to generate phase change in 2π range. The modulation transfer function was also measured.

Functional role for suppression of the insular-striatal circuit in modulating interoceptive effects of alcohol.

PubMed

Jaramillo, Anel A; Agan, Verda E; Makhijani, Viren H; Pedroza, Stephen; McElligott, Zoe A; Besheer, Joyce

2017-09-27

The insular cortex (IC) is a region proposed to modulate, in part, interoceptive states and motivated behavior. Interestingly, IC dysfunction and deficits in interoceptive processing are often found among individuals with substance-use disorders. Furthermore, the IC projects to the nucleus accumbens core (AcbC), a region known to modulate the discriminative stimulus/interoceptive effects of alcohol and other drug-related behaviors. Therefore, the goal of the present work was to investigate the possible role of the IC ➔ AcbC circuit in modulating the interoceptive effects of alcohol. Thus, we utilized a chemogenetic technique (hM4D i designer receptor activation by designer drugs) to silence neuronal activity in the IC of rats trained to discriminate alcohol (1 g/kg, IG) versus water using an operant or Pavlovian alcohol discrimination procedure. Chemogenetic silencing of the IC or IC ➔ AcbC neuronal projections resulted in potentiated sensitivity to the interoceptive effects of alcohol in both the operant and Pavlovian tasks. Together, these data provide critical evidence for the nature of the complex IC circuitry and, specifically, suppression of the insular-striatal circuit in modulating behavior under a drug stimulus control. © 2017 Society for the Study of Addiction.

Motor modules during adaptation to walking in a powered ankle exoskeleton.

PubMed

Jacobs, Daniel A; Koller, Jeffrey R; Steele, Katherine M; Ferris, Daniel P

2018-01-03

Modules of muscle recruitment can be extracted from electromyography (EMG) during motions, such as walking, running, and swimming, to identify key features of muscle coordination. These features may provide insight into gait adaptation as a result of powered assistance. The aim of this study was to investigate the changes (module size, module timing and weighting patterns) of surface EMG data during assisted and unassisted walking in an powered, myoelectric, ankle-foot orthosis (ankle exoskeleton). Eight healthy subjects wore bilateral ankle exoskeletons and walked at 1.2 m/s on a treadmill. In three training sessions, subjects walked for 40 min in two conditions: unpowered (10 min) and powered (30 min). During each session, we extracted modules of muscle recruitment via nonnegative matrix factorization (NNMF) from the surface EMG signals of ten muscles in the lower limb. We evaluated reconstruction quality for each muscle individually using R 2 and normalized root mean squared error (NRMSE). We hypothesized that the number of modules needed to reconstruct muscle data would be the same between conditions and that there would be greater similarity in module timings than weightings. Across subjects, we found that six modules were sufficient to reconstruct the muscle data for both conditions, suggesting that the number of modules was preserved. The similarity of module timings and weightings between conditions was greater then random chance, indicating that muscle coordination was also preserved. Motor adaptation during walking in the exoskeleton was dominated by changes in the module timings rather than module weightings. The segment number and the session number were significant fixed effects in a linear mixed-effect model for the increase in R 2 with time. Our results show that subjects walking in a exoskeleton preserved the number of modules and the coordination of muscles within the modules across conditions. Training (motor adaptation within the session and motor skill consolidation across sessions) led to improved consistency of the muscle patterns. Subjects adapted primarily by changing the timing of their muscle patterns rather than the weightings of muscles in the modules. The results of this study give new insight into strategies for muscle recruitment during adaptation to a powered ankle exoskeleton.

Health Instruction Packages: Consumer--Birth Control.

ERIC Educational Resources Information Center

Pries, Rose Mary; And Others

Designed for the general public, these three learning modules utilize text, illustrations, and exercises to describe various methods of birth control. The first module, "All about Contraception for the Teenage New Mother" by Rose Mary Pries, discusses the desirability of planned pregnancy and reviews the effectiveness and side effects of…

Stress Modulates the Use of Spatial versus Stimulus-Response Learning Strategies in Humans

ERIC Educational Resources Information Center

Philippsen, Christine; Richter, Steffen; Bohringer, Andreas; Wippich, Werner; Schachinger, Hartmut; Schwabe, Lars; Oitzl, Melly S.

2007-01-01

Animal studies provided evidence that stress modulates multiple memory systems, favoring caudate nucleus-based "habit" memory over hippocampus-based "cognitive" memory. However, effects of stress on learning strategy and memory consolidation were not differentiated. We specifically address the effects of psychosocial stress on the applied learning…

The effect of different module configurations on the radiation tolerance of multijunction solar cells

NASA Technical Reports Server (NTRS)

Gee, James M.; Curtis, Henry B.

1988-01-01

The effect of different module configurations on the performance of multijunction (MJ) solar cells in a radiation environment was investigated. Module configuration refers to the electrical circuit in which the subcells of the multijunction cell are wired. Experimental data for AlCaAs, GaAs, InGaAs, and silicon single-junction concentrator cells subjected to 1 MeV electron irradiation was used to calculate the expected performance of AlGaAs/InGaAs, AlGa/silicon, GaAs/InGaAs, and GaAs/silicon Mj concentrator cells. These calculations included independent, series, and voltage-matched configurations. The module configuration was found to have a significant impact on the radiation tolerance characteristic of the MJ cells.

Linearity optimizations of analog ring resonator modulators through bias voltage adjustments

NASA Astrophysics Data System (ADS)

Hosseinzadeh, Arash; Middlebrook, Christopher T.

2018-03-01

The linearity of ring resonator modulator (RRM) in microwave photonic links is studied in terms of instantaneous bandwidth, fabrication tolerances, and operational bandwidth. A proposed bias voltage adjustment method is shown to maximize spur-free dynamic range (SFDR) at instantaneous bandwidths required by microwave photonic link (MPL) applications while also mitigating RRM fabrication tolerances effects. The proposed bias voltage adjustment method shows RRM SFDR improvement of ∼5.8 dB versus common Mach-Zehnder modulators at 500 MHz instantaneous bandwidth. Analyzing operational bandwidth effects on SFDR shows RRMs can be promising electro-optic modulators for MPL applications which require high operational frequencies while in a limited bandwidth such as radio-over-fiber 60 GHz wireless network access.

Coordinated therapeutic effects of immune modulators and interferon.

PubMed Central

Cerutti, I; Chany, C

1983-01-01

Immune modulators injected 24 h before encephalomyocarditis virus significantly increase antiviral resistance in mice when interferon is administered 1 h after the virus. These immune modulators can be crude bacterial extracts or synthetic drugs. In some cases, the responses are additive; in others, they are clearly cooperative. To protect the mice against the development of 180 TG Crocker sarcomas, the association of bacterial extracts and interferon is highly effective under the condition that the drug concentrations and chronological order and number of injections are well defined. In contrast, the conjunction of interferon and synthetic immune modulators, in particular cimetidine, result in delayed tumor development with no significant change in the final survival rate in the experimental model described here. PMID:6315585

Development of thermally controlled HALNA DPSSL for inertial fusion energy

NASA Astrophysics Data System (ADS)

Matsumoto, Osamu; Yasuhara, Ryo; Kurita, Takashi; Ikegawa, Tadashi; Sekine, Takashi; Kawashima, Toshiyuki; Kawanaka, Junji; Norimatsu, Takayoshi; Miyanaga, Noriaki; Izawa, Yasukazu; Nakatsuka, Masahiro; Miyamoto, Masahiro; Kan, Hirofumi; Furukawa, Hiroyuki; Motokoshi, Shinji

2006-02-01

We have been developing a high average-power laser system for science and industry applications that can generate an output of 20 J per pulse at 10-Hz operation. Water-cooled Nd:glass zig-zag slab is pumped with 803-nm AlGaAs laser-diode modules. To efficiently extract energy from the laser medium, the laser beam alternately passes through dual zig-zag slab amplifier modules. Twin LD modules equipped on each slab amplifier module pump the laser medium with a peak power density of 2.5 kW/cm2. In high power laser system, thermal load in the laser medium causes serious thermal effects. We arranged cladding glasses on the top and bottom of the laser slab to reduce thermal effects.

Flicker in a twisted nematic spatial light modulator

NASA Astrophysics Data System (ADS)

Calderón-Hermosillo, Yuliana; García-Márquez, Jorge; Espinosa-Luna, Rafael; Ochoa, Noé Alcalá; López, Víctor; Aguilar, Alberto; Noé-Arias, Enrique; Alayli, Yasser

2013-06-01

Liquid Crystal on Silicon (LCoS) Spatial Light Modulators (SLM) are widely used for their capability to control beams howbeit fluctuations in phase and amplitude. It is then necessary to understand the negative effects of these fluctuations, also known as flicker, and the means to mitigate them. The flicker is observed either as high frequency variations of polarization, attenuation or high phase fluctuations on the wave front modulated by the LCoS device. Here, we compare the flicker behavior in a twisted nematic (TN) LCoS-SLM for different polarization schemes and temperatures. The quantitative evaluation shows that flicker is effectively reduced only by chilling the LCoS panel to temperatures just below 0 °C but, the LCoS modulation capability is also affected.

Panning for SNuRMs: using cofactor profiling for the rational discovery of selective nuclear receptor modulators.

PubMed

Kremoser, Claus; Albers, Michael; Burris, Thomas P; Deuschle, Ulrich; Koegl, Manfred

2007-10-01

Drugs that target nuclear receptors are clinically, as well as commercially, successful. Their widespread use, however, is limited by an inherent propensity of nuclear receptors to trigger beneficial, as well as adverse, pharmacological effects upon drug activation. Hence, selective drugs that display reduced adverse effects, such as the selective estrogen receptor modulator (SERM) Raloxifene, have been developed by guidance through classical cell culture assays and animal trials. Full agonist and selective modulator nuclear receptor drugs, in general, differ by their ability to recruit certain cofactors to the receptor protein. Hence, systematic cofactor profiling is advancing into an approach for the rationally guided identification of selective NR modulators (SNuRMs) with improved therapeutic ratio.

The physical basis for absorption of light. [effects on wave functions of gas molecules and atoms

NASA Technical Reports Server (NTRS)

Pickett, H. M.

1979-01-01

The effects of light absorption on the wave functions of gas-phase molecules and atoms are investigated by high resolution spectral measurements of radiation emerging from a sample. A Stark-modulated sample of methyl fluoride was irradiated at the 102 GHz rotational transition and the emergent radiation was resolved by means of a spectrum analyzer. For signal oscillator frequencies below or above the molecular resonance by one modulation frequency, the amplitudes of the upper and lower modulation sidebands are found to be of nonuniform intensity, which is inconsistent with amplitude modulation. Emission due to polarization is, however, calculated to be consistent with the results observed, indicating that light absorption should be considered as a subtractive stimulated emission.

X-ray verification of an optically aligned off-plane grating module

NASA Astrophysics Data System (ADS)

Donovan, Benjamin D.; McEntaffer, Randall L.; Tutt, James H.; DeRoo, Casey T.; Allured, Ryan; Gaskin, Jessica A.; Kolodziejczak, Jeffery J.

2018-01-01

Off-plane x-ray reflection gratings are theoretically capable of achieving high resolution and high diffraction efficiencies over the soft x-ray bandpass, making them an ideal technology to implement on upcoming x-ray spectroscopy missions. To achieve high effective area, these gratings must be aligned into grating modules. X-ray testing was performed on an aligned grating module to assess the current optical alignment methods. Results indicate that the grating module achieved the desired alignment for an upcoming x-ray spectroscopy suborbital rocket payload with modest effective area and resolving power. These tests have also outlined a pathway towards achieving the stricter alignment tolerances of future x-ray spectrometer payloads, which require improvements in alignment metrology, grating fabrication, and testing techniques.

Antibody induced CD4 down-modulation of T cells is site-specifically mediated by CD64+ cells

PubMed Central

Vogel, Stephanie; Grabski, Elena; Buschjäger, Daniela; Klawonn, Frank; Döring, Marius; Wang, Junxi; Fletcher, Erika; Bechmann, Ingo; Witte, Torsten; Durisin, Martin; Schraven, Burkhart; Mangsbo, Sara M.; Schönfeld, Kurt; Czeloth, Niklas; Kalinke, Ulrich

2015-01-01

Treatment of PBMC with the CD4-specific mAb BT-061 induces CD4 down-modulation of T cells. Here we report that addition of BT-061 to purified T cells did not confer this effect, whereas incubation of T cells in BT-061 coated wells restored CD4 down-modulation. These results implied that Fcγ receptor mediated cell-cell interactions played a role. In consistence with this hypothesis PBMC depleted of CD64+ monocytes did not confer CD4 down-modulation of BT-061 decorated T cells. Strikingly, CD4 down-modulation was observed in BT-061 treated synovial fluid punctuated from patients’ inflamed joints that comprised enhanced numbers of CD64+ cells. In contrast, in a circulating whole blood system injection of BT-061 did not induce CD4 down-modulation, due to CD64 saturation by serum IgG. Similarly, tonsil derived mononuclear cells devoid of CD64+ cells did not show CD4 down-modulation, whereas addition of blood derived monocytes restored the effect. Thus, the interaction of BT-061 decorated T cells with CD64+ cells is needed for CD4 down-modulation, implying that in patients BT-061 would primarily induce CD4 down-modulation at inflammatory sites. These results highlight the need not only to examine the interaction of a given mAb with single FcγR, but also the immunological environment that is appropriate to support such interactions. PMID:26670584

An investigation into the effects of frequency-modulated transcutaneous electrical nerve stimulation (TENS) on experimentally-induced pressure pain in healthy human participants.

PubMed

Chen, Chih-Chung; Johnson, Mark I

2009-10-01

Frequency-modulated transcutaneous electrical nerve stimulation (TENS) delivers currents that fluctuate between preset boundaries over a fixed period of time. This study compared the effects of constant-frequency TENS and frequency-modulated TENS on blunt pressure pain in healthy human volunteers. Thirty-six participants received constant-frequency TENS (80 pps), frequency-modulated TENS (20 to 100 pps), and placebo (no current) TENS at a strong nonpainful intensity in a randomized cross-over manner. Pain threshold was taken from the forearm using pressure algometry. There were no statistical differences between constant-frequency TENS and frequency-modulated TENS after 20 minutes (OR = 1.54; CI, 0.29, 8.23, P = 1.0). Both constant-frequency TENS and frequency-modulated TENS were superior to placebo TENS (OR = 59.5, P < .001 and OR = 38.5, P < .001, respectively). Frequency-modulated TENS does not influence hypoalgesia to any greater extent than constant-frequency TENS when currents generate a strong nonpainful paraesthesia at the site of pain. The finding that frequency-modulated TENS and constant-frequency TENS were superior to placebo TENS provides further evidence that a strong yet nonpainful TENS intensity is a prerequisite for hypoalgesia. This study provides evidence that TENS, delivered at a strong nonpainful intensity, increases pain threshold to pressure algometry in healthy participants over and above that seen with placebo (no current) TENS. Frequency-modulated TENS does not increase hypoalgesia to any appreciable extent to that seen with constant-frequency TENS.

Static and Dynamic Effects of Lateral Carrier Diffusion in Semiconductor Lasers

NASA Technical Reports Server (NTRS)

Li, Jian-Zhong; Cheung, Samson H.; Ning, C. Z.; Biegel, Bryan A. (Technical Monitor)

2002-01-01

Electron and hole diffusions in the plane of semiconductor quantum wells play an important part in the static and dynamic operations of semiconductor lasers. It is well known that the value of diffusion coefficients affects the threshold pumping current of a semiconductor laser. At the same time, the strength of carrier diffusion process is expected to affect the modulation bandwidth of an AC-modulated laser. It is important not only to investigate the combined DC and AC effects due to carrier diffusion, but also to separate the AC effects from that of the combined effects in order to provide design insights for high speed modulation. In this presentation, we apply a hydrodynamic model developed by the present authors recently from the semiconductor Bloch equations. The model allows microscopic calculation of the lateral carrier diffusion coefficient, which is a nonlinear function of the carrier density and plasma temperature. We first studied combined AC and DC effects of lateral carrier diffusion by studying the bandwidth dependence on diffusion coefficient at a given DC current under small signal modulation. The results show an increase of modulation bandwidth with decrease in the diffusion coefficient. We simultaneously studied the effects of nonlinearity in the diffusion coefficient. To clearly identify how much of the bandwidth increase is a result of decrease in the threshold pumping current for smaller diffusion coefficient, thus an effective increase of DC pumping, we study the bandwidth dependence on diffusion coefficient at a given relative pumping. A detailed comparison of the two cases will be presented.

The Effects of Cognitive Conflict Management on Cognitive Development and Science Achievement

ERIC Educational Resources Information Center

Budiman, Zainol Badli; Halim, Lilia; Mohd Meerah, Subahan; Osman, Kamisah

2014-01-01

Three teaching methods were compared in this study, namely a Cognitive Conflict Management Module (CCM) that is infused into Cognitive Acceleration through Science Education (CASE), (Module A) CASE without CCM (Module B) and a conventional teaching method. This study employed a pre- and post-test quasi-experimental design using non-equivalent…

Development and Evaluation of the SUMIT Microcomputer Module Entitled 'Predator Functional Response'.

ERIC Educational Resources Information Center

Shaltz, Mark B.

An experiment was conducted that compared the teaching effectiveness of a computer assisted instructional module and a lecture-discussion. The module, Predator Functional Response (PFR), was developed as part of the SUMIT (Single-concept User-adaptable Microcomputer-based Instructional Technique) project. A class of 30 students was randomly…

Use of Handwriting Recognition Technologies in Tablet-Based Learning Modules for First Grade Education

ERIC Educational Resources Information Center

Yanikoglu, Berrin; Gogus, Aytac; Inal, Emre

2017-01-01

Learning through modules on a tablet helps students participate effectively in learning activities in classrooms and provides flexibility in the learning process. This study presents the design and evaluation of an application that is based on handwriting recognition technologies and e-content for the developed learning modules. The application…

Working with Our Publics. In-Service Education for Cooperative Extension. Module 6. Education for Public Decisions.

ERIC Educational Resources Information Center

House, Verne W.; Young, Ardis Armstrong

This module is the sixth in an inservice education series for extension professionals that consists of seven independent training modules. It provides inservice education in analyzing public problems, anticipating the consequences of extension's involvement in issues, and working effectively in areas of controversy. The following five units…

Assessment of Computer-Mediated Module Intervention in a Pharmacy Calculations Course

ERIC Educational Resources Information Center

Bell, Edward C.; Fike, David S.; Liang, Dong; Lockman, Paul R.; McCall, Kenneth L.

2017-01-01

Computer module intervention is the process of exposing students to a series of discrete exercises for the purpose of strengthening students' familiarity with conceptual material. The method has been suggested as a remedy to student under-preparedness. This study was conducted to determine the effectiveness of module intervention in improving and…

The Impact of Interactive, Computerized Educational Modules on Preclinical Medical Education

ERIC Educational Resources Information Center

Bryner, Benjamin S.; Saddawi-Konefka, Daniel; Gest, Thomas R.

2008-01-01

Interactive computerized modules have been linked to improved retention of material in clinical medicine. This study examined the effects of a new series of interactive learning modules for preclinical medical education, specifically in the areas of quiz performance, perceived difficulty of concepts, study time, and perceived stress level. We…

Online Video Modules for Improvement in Student Learning

ERIC Educational Resources Information Center

Lancellotti, Matthew; Thomas, Sunil; Kohli, Chiranjeev

2016-01-01

The objective of this teaching innovation was to incorporate a comprehensive set of short online video modules covering key topics from the undergraduate principles of marketing class, and to evaluate its effectiveness in improving student learning. A quasiexperimental design was used to compare students who had access to video modules with a…

Intersection-Controller Software Module

NASA Technical Reports Server (NTRS)

Bachelder, Aaron; Foster, Conrad

2005-01-01

An important part of the emergency-vehicle traffic-light-preemption system summarized in the preceding article is a software module executed by a microcontroller in each intersection controller. This module monitors the broadcasts from all nearby participating emergency vehicles and intersections. It gathers the broadcast data pertaining to the positions and velocities of the vehicles and the timing of traffic and pedestrian lights and processes the data into predictions of the future positions of the vehicles. Analyzing the predictions by a combination of proximity tests, map-matching techniques, and statistical calculations designed to minimize the adverse effects of uncertainties in vehicle positions and headings, the module decides whether to preempt and issues the appropriate commands to the traffic lights, pedestrian lights, and electronic warning signs at the intersection. The module also broadcasts its state to all nearby vehicles and intersections. The module is designed to mitigate the effects of missing data and of unpredictable delays in the system. It has been intensively tested and refined so that it fails to warn in very few cases and issues very few false warnings.

On the Effects of a Spacecraft Subcarrier Unbalanced Modulator

NASA Technical Reports Server (NTRS)

Nguyen, Tien Manh

1993-01-01

This paper presents mathematical models with associated analysis of the deleterious effects which a spacecraft's subcarrier unbalanced modulator has on the performance of a phase-modulated residual carrier communications link. The undesired spectral components produced by the phase and amplitude imbalances in the subcarrier modulator can cause (1) potential interference to the carrier tracking and (2) degradation in the telemetry bit signal-to-noise ratio (SNR). A suitable model for the unbalanced modulator is developed and the threshold levels of undesired components that fall into the carrier tracking loop are determined. The distribution of the carrier phase error caused by the additive White Gaussian noise (AWGN) and undesired component at the residual RF carrier is derived for the limiting cases. Further, this paper analyses the telemetry bit signal-to-noise ratio degradations due to undesirable spectral components as well as the carrier tracking phase error induced by phase and amplitude imbalances. Numerical results which indicate the sensitivity of the carrier tracking loop and the telemetry symbol-error rate (SER) to various parameters of the models are also provided as a tool in the design of the subcarrier balanced modulator.

Solvent induced rapid modulation of micro/nano structures of metal carboxylates coordination polymers: mechanism and morphology dependent magnetism.

PubMed

Liu, Kun; Shen, Zhu-Rui; Li, Yue; Han, Song-De; Hu, Tong-Liang; Zhang, Da-Shuai; Bu, Xian-He; Ruan, Wen-Juan

2014-08-12

Rational modulation of morphology is very important for functional coordination polymers (CPs) micro/nanostructures, and new strategies are still desired to achieve this challenging target. Herein, organic solvents have been established as the capping agents for rapid modulating the growth of metal-carboxylates CPs in organic solvent/water mixtures at ambient conditions. Co-3,5-pyridinedicarboxylate (pydc) CPs was studied here as the example. During the reaction, the organic solvents exhibited three types of modulation effect: anisotropic growth, anisotropic growth/formation of new crystalline phase and the formation of new crystalline phase solely, which was due to the variation of their binding ability with metal cations. The following study revealed that the binding ability was critically affected by their functional groups and molecular size. Moreover, their modulation effect could be finely tuned by changing volume ratios of solvent mixtures. Furthermore, they could be applied for modulating other metal-carboxylates CPs: Co-1,3,5-benzenetricarboxylic (BTC), Zn-pydc and Eu-pydc etc. Additionally, the as-prepared Co-pydc CPs showed a fascinating morphology-dependent antiferromagnetic behavior.

Solvent induced rapid modulation of micro/nano structures of metal carboxylates coordination polymers: mechanism and morphology dependent magnetism

NASA Astrophysics Data System (ADS)

Liu, Kun; Shen, Zhu-Rui; Li, Yue; Han, Song-De; Hu, Tong-Liang; Zhang, Da-Shuai; Bu, Xian-He; Ruan, Wen-Juan

2014-08-01

Rational modulation of morphology is very important for functional coordination polymers (CPs) micro/nanostructures, and new strategies are still desired to achieve this challenging target. Herein, organic solvents have been established as the capping agents for rapid modulating the growth of metal-carboxylates CPs in organic solvent/water mixtures at ambient conditions. Co-3,5-pyridinedicarboxylate (pydc) CPs was studied here as the example. During the reaction, the organic solvents exhibited three types of modulation effect: anisotropic growth, anisotropic growth/formation of new crystalline phase and the formation of new crystalline phase solely, which was due to the variation of their binding ability with metal cations. The following study revealed that the binding ability was critically affected by their functional groups and molecular size. Moreover, their modulation effect could be finely tuned by changing volume ratios of solvent mixtures. Furthermore, they could be applied for modulating other metal-carboxylates CPs: Co-1,3,5-benzenetricarboxylic (BTC), Zn-pydc and Eu-pydc etc. Additionally, the as-prepared Co-pydc CPs showed a fascinating morphology-dependent antiferromagnetic behavior.

Solvent induced rapid modulation of micro/nano structures of metal carboxylates coordination polymers: mechanism and morphology dependent magnetism

PubMed Central

Liu, Kun; Shen, Zhu-Rui; Li, Yue; Han, Song-De; Hu, Tong-Liang; Zhang, Da-Shuai; Bu, Xian-He; Ruan, Wen-Juan

2014-01-01

Rational modulation of morphology is very important for functional coordination polymers (CPs) micro/nanostructures, and new strategies are still desired to achieve this challenging target. Herein, organic solvents have been established as the capping agents for rapid modulating the growth of metal-carboxylates CPs in organic solvent/water mixtures at ambient conditions. Co-3,5-pyridinedicarboxylate (pydc) CPs was studied here as the example. During the reaction, the organic solvents exhibited three types of modulation effect: anisotropic growth, anisotropic growth/formation of new crystalline phase and the formation of new crystalline phase solely, which was due to the variation of their binding ability with metal cations. The following study revealed that the binding ability was critically affected by their functional groups and molecular size. Moreover, their modulation effect could be finely tuned by changing volume ratios of solvent mixtures. Furthermore, they could be applied for modulating other metal-carboxylates CPs: Co-1,3,5-benzenetricarboxylic (BTC), Zn-pydc and Eu-pydc etc. Additionally, the as-prepared Co-pydc CPs showed a fascinating morphology-dependent antiferromagnetic behavior. PMID:25113225

Pulse Shaped 8-PSK Bandwidth Efficiency and Spectral Spike Elimination

NASA Technical Reports Server (NTRS)

Tao, Jian-Ping

1998-01-01

The most bandwidth-efficient communication methods are imperative to cope with the congested frequency bands. Pulse shaping methods have excellent effects on narrowing bandwidth and increasing band utilization. The position of the baseband filters for the pulse shaping is crucial. Post-modulation pulse shaping (a low pass filter is located after the modulator) can change signals from constant envelope to non-constant envelope, and non-constant envelope signals through non-linear device (a SSPA or TWT) can further spread the power spectra. Pre-modulation pulse shaping (a filter is located before the modulator) will have constant envelope. These two pulse shaping methods have different effects on narrowing the bandwidth and producing bit errors. This report studied the effect of various pre-modulation pulse shaping filters with respect to bandwidth, spectral spikes and bit error rate. A pre-modulation pulse shaped 8-ary Phase Shift Keying (8PSK) modulation was used throughout the simulations. In addition to traditional pulse shaping filters, such as Bessel, Butterworth and Square Root Raised Cosine (SRRC), other kinds of filters or pulse waveforms were also studied in the pre-modulation pulse shaping method. Simulations were conducted by using the Signal Processing Worksystem (SPW) software package on HP workstations which simulated the power spectral density of pulse shaped 8-PSK signals, end to end system performance and bit error rates (BERS) as a function of Eb/No using pulse shaping in an AWGN channel. These results are compared with the post-modulation pulse shaped 8-PSK results. The simulations indicate traditional pulse shaping filters used in pre-modulation pulse shaping may produce narrower bandwidth, but with worse BER than those in post-modulation pulse shaping. Theory and simulations show pre- modulation pulse shaping could also produce discrete line power spectra (spikes) at regular frequency intervals. These spikes may cause interference with adjacent channel and reduce power efficiency. Some particular pulses (filters), such as trapezoid and pulses with different transits (such as weighted raised cosine transit) were found to reduce bandwidth and not generate spectral spikes. Although a solid state power amplifier (SSPA) was simulated in the non-linear (saturation) region, output power spectra did not spread due to the constant envelope 8-PSK signals.

Tunable microwave photonic filter free from baseband and carrier suppression effect not requiring single sideband modulation using a Mach-Zenhder configuration.

PubMed

Mora, José; Ortigosa-Blanch, Arturo; Pastor, Daniel; Capmany, José

2006-08-21

We present a full theoretical and experimental analysis of a novel all-optical microwave photonic filter combining a mode-locked fiber laser and a Mach-Zenhder structure in cascade to a 2x1 electro-optic modulator. The filter is free from the carrier suppression effect and thus it does not require single sideband modulation. Positive and negative coefficients are obtained inherently in the system and the tunability is achieved by controlling the optical path difference of the Mach-Zenhder structure.

Effectiveness of Online Module for Graduate Astronomy Course

NASA Astrophysics Data System (ADS)

Campbell, Lauren E. P.; Holley-Bockelmann, Kelly; Brame, Cynthia

2017-01-01

We noticed that teaching an important galaxy formation model in a graduate-level course (Structure and Dynamics of Galaxies) with lecture-style instruction did not promote active learning on the part of the student and that the level and quality of in-class discussion varied wildly from semester to semester. Hoping to improve the learning experience for the students, we designed and incorporated an online module to deliver course content, activities, and assessments. We investigate the effectiveness of this online module as a teaching tool by monitoring students’ learning gains and present our preliminary results.

A New Look at the Blazhko Effect in RR Lyrae Stars with High-Quality Data from the MACHO Project

NASA Astrophysics Data System (ADS)

Kurtz, D. W.; Alcock, C.; Allsman, R. A.; Alves, D.; Axelrod, T. S.; Becker, A. C.; Bennett, D. P.; Cook, K. H.; Freeman, K. C.; Griest, K.; Lehner, M. J.; Marshall, S. L.; Minniti, D.; Peterson, B. A.; Pratt, M. R.; Quinn, P. J.; Rodgers, A. W.; Stubbs, C. W.; Sutherland, W.; Tomaney, A.; Welch, D. L.; MACHO Collaboration

We present the first results of the analysis of 22 Blazhko stars. We find: 1) Blazhko RRab stars that are nearly pure amplitude modulators; 2) Blazhko RRab stars that have both amplitude and phase modulation; 3) A Blazhko RRab star that has an abrupt period change; 4) Proof of the Blazhko effect in RRc stars. Our data show the character of the amplitude and phase modulations of the light curves over the Blazhko cycles far better than has been previously possible.

Evaluation of a Digital Game-Based Learning Program for Enhancing Youth Mental Health: A Structural Equation Modeling of the Program Effectiveness.

PubMed

Huen, Jenny My; Lai, Eliza Sy; Shum, Angie Ky; So, Sam Wk; Chan, Melissa Ky; Wong, Paul Wc; Law, Y W; Yip, Paul Sf

2016-10-07

Digital game-based learning (DGBL) makes use of the entertaining power of digital games for educational purposes. Effectiveness assessment of DGBL programs has been underexplored and no attempt has been made to simultaneously model both important components of DGBL: learning attainment (ie, educational purposes of DGBL) and engagement of users (ie, entertaining power of DGBL) in evaluating program effectiveness. This study aimed to describe and evaluate an Internet-based DGBL program, Professor Gooley and the Flame of Mind, which promotes mental health to adolescents in a positive youth development approach. In particular, we investigated whether user engagement in the DGBL program could enhance their attainment on each of the learning constructs per DGBL module and subsequently enhance their mental health as measured by psychological well-being. Users were assessed on their attainment on each learning construct, psychological well-being, and engagement in each of the modules. One structural equation model was constructed for each DGBL module to model the effect of users' engagement and attainment on the learning construct on their psychological well-being. Of the 498 secondary school students that registered and participated from the first module of the DGBL program, 192 completed all 8 modules of the program. Results from structural equation modeling suggested that a higher extent of engagement in the program activities facilitated users' attainment on the learning constructs on most of the modules and in turn enhanced their psychological well-being after controlling for users' initial psychological well-being and initial attainment on the constructs. This study provided evidence that Internet intervention for mental health, implemented with the technologies and digital innovations of DGBL, could enhance youth mental health. Structural equation modeling is a promising approach in evaluating the effectiveness of DGBL programs.

Audio-visual speech perception: a developmental ERP investigation

PubMed Central

Knowland, Victoria CP; Mercure, Evelyne; Karmiloff-Smith, Annette; Dick, Fred; Thomas, Michael SC

2014-01-01

Being able to see a talking face confers a considerable advantage for speech perception in adulthood. However, behavioural data currently suggest that children fail to make full use of these available visual speech cues until age 8 or 9. This is particularly surprising given the potential utility of multiple informational cues during language learning. We therefore explored this at the neural level. The event-related potential (ERP) technique has been used to assess the mechanisms of audio-visual speech perception in adults, with visual cues reliably modulating auditory ERP responses to speech. Previous work has shown congruence-dependent shortening of auditory N1/P2 latency and congruence-independent attenuation of amplitude in the presence of auditory and visual speech signals, compared to auditory alone. The aim of this study was to chart the development of these well-established modulatory effects over mid-to-late childhood. Experiment 1 employed an adult sample to validate a child-friendly stimulus set and paradigm by replicating previously observed effects of N1/P2 amplitude and latency modulation by visual speech cues; it also revealed greater attenuation of component amplitude given incongruent audio-visual stimuli, pointing to a new interpretation of the amplitude modulation effect. Experiment 2 used the same paradigm to map cross-sectional developmental change in these ERP responses between 6 and 11 years of age. The effect of amplitude modulation by visual cues emerged over development, while the effect of latency modulation was stable over the child sample. These data suggest that auditory ERP modulation by visual speech represents separable underlying cognitive processes, some of which show earlier maturation than others over the course of development. PMID:24176002

Modulation of neonatal microbial recognition: TLR-mediated innate immune responses are specifically and differentially modulated by human milk.

PubMed

LeBouder, Emmanuel; Rey-Nores, Julia E; Raby, Anne-Catherine; Affolter, Michael; Vidal, Karine; Thornton, Catherine A; Labéta, Mario O

2006-03-15

The mechanisms controlling innate microbial recognition in the neonatal gut are still to be fully understood. We have sought specific regulatory mechanisms operating in human breast milk relating to TLR-mediated microbial recognition. In this study, we report a specific and differential modulatory effect of early samples (days 1-5) of breast milk on ligand-induced cell stimulation via TLRs. Although a negative modulation was exerted on TLR2 and TLR3-mediated responses, those via TLR4 and TLR5 were enhanced. This effect was observed in human adult and fetal intestinal epithelial cell lines, monocytes, dendritic cells, and PBMC as well as neonatal blood. In the latter case, milk compensated for the low capacity of neonatal plasma to support responses to LPS. Cell stimulation via the IL-1R or TNFR was not modulated by milk. This, together with the differential effect on TLR activation, suggested that the primary effect of milk is exerted upstream of signaling proximal to TLR ligand recognition. The analysis of TLR4-mediated gene expression, used as a model system, showed that milk modulated TLR-related genes differently, including those coding for signal intermediates and regulators. A proteinaceous milk component of > or =80 kDa was found to be responsible for the effect on TLR4. Notably, infant milk formulations did not reproduce the modulatory activity of breast milk. Together, these findings reveal an unrecognized function of human milk, namely, its capacity to influence neonatal microbial recognition by modulating TLR-mediated responses specifically and differentially. This in turn suggests the existence of novel mechanisms regulating TLR activation.

The effectiveness of game and recreational activity to motivate high achievers and low achievers: Evaluation using fuzzy conjoint analysis

NASA Astrophysics Data System (ADS)

Sofian, Siti Siryani; Rambely, Azmin Sham

2018-04-01

Students' evaluation is important in order to determine the effectiveness of a learning program. A game and recreational activity (GaRA) is a problem-based learning (PBL) method that engages students in a learning process through games and activity. The effectiveness of GaRA can be determined from an application of fuzzy conjoint analysis (FCA) to diminish fuzziness in determining individual perceptions. This study involves a survey collected from 68 students participating in a Mathematics Discovery Camp organized by a UKM research group, named PRISMatik, from two different schools. The aim of this research was to determine the effectiveness of modules delivered to motivate students towards mathematics subject in the form of GaRA through different factors. There were six games conducted for the participants and their perceptions based on the evaluation of six criterias were measured. A seven-point Likert scale, which indicates seven linguistic terms, was used to collect students' preferences and perceptions on each module of GaRAs. Scores of perceptions were transformed into degrees of similarity using fuzzy set conjoint analysis. Results found that interest, effort and team work was the strongest values obtained from GaRA modules in this camp as participants indicated their strong agreement that these criteria fulfilled their preferences in most module. Participants also stated that almost all attributes fulfilled their preference in each module regardless their individual academic achievement. Thus the method demonstrated that modules delivered through PBL approach has effectively motivated students through six attributes introduced. The evaluation using FCA implicated the successfulness of a fuzzy approach to evaluate fuzziness obtained in the Likert-scale and has shown its ability in ranking the attributes from most preferred to least preferred.

Development of Mirror Modules for the ART-XC Instrument

NASA Technical Reports Server (NTRS)

Gubarev, M.; Ramsey, B.; O'Dell, S. L.; Elsner, R.; Kilaru, K.; McCracken, J.; Pavlinsky, M.; Lapshov, I.

2012-01-01

The Marshall Space Flight Center (MSFC) is developing x-ray mirror modules for the ART -XC instrument on board the Spectrum-Roentgen-Gamma Mission under a Reimbursable Agreement between NASA and the Russian Space Research Institute (IKI.) ART-XC will consist of seven co-aligned x-ray mirror modules with seven corresponding CdTe focal plane detectors. Currently, four of the modules are being fabricated by the Marshall Space Flight Center (MSFC.) Each MSFC module provides an effective area of 65 cm2 at 8 keV, response out to 30 keV, and an angular resolution of 45 arcsec or better HPD. We will present a status of the ART x-ray module development at MSFC.

Membrane anchoring γ-secretase modulators with terpene-derived moieties.

PubMed

Naumann, Eva Christine; Göring, Stefan; Ogorek, Isabella; Weggen, Sascha; Schmidt, Boris

2013-07-01

Modulation of γ-secretase activity is a promising therapeutic strategy for the treatment of Alzheimer's disease. Herein we report on the synthesis of carprofen- and tocopherol-derived small-molecule modulators carrying terpene moieties as lipophilic membrane anchors. Additionally, these modulators are equipped with an acidic moiety, which contributes to the desired modulatory effect on the γ-secretase with decreased formation of Aβ42 and increased Aβ38 production. Copyright © 2013 Elsevier Ltd. All rights reserved.

High frequency GaAlAs modulator and photodetector for phased array antenna applications

NASA Technical Reports Server (NTRS)

Claspy, P. C.; Chorey, C. M.; Hill, S. M.; Bhasin, K. B.

1988-01-01

A waveguide Mach-Zehnder electro-optic modulator and an interdigitated photoconductive detector designed to operate at 820 nm, fabricated on different GaAlAs/GaAs heterostructure materials, are being investigated for use in optical interconnects in phased array antenna systems. Measured optical attenuation effects in the modulator are discussed and the observed modulation performance up to 1 GHz is presented. Measurements of detector frequency response are described and results presented.

The Effect of Modulation Ratio of Cu/Ni Multilayer Films on the Fretting Damage Behaviour of Ti-811 Titanium Alloy.

PubMed

Zhang, Xiaohua; Liu, Daoxin; Li, Xiaoying; Dong, Hanshan; Xi, Yuntao

2017-05-26

To improve the fretting damage (fretting wear and fretting fatigue) resistance of Ti-811 titanium alloy, three Cu/Ni multilayer films with the same modulation period thickness (200 nm) and different modulation ratios (3:1, 1:1, 1:3) were deposited on the surface of the alloy via ion-assisted magnetron sputtering deposition (IAD). The bonding strength, micro-hardness, and toughness of the films were evaluated, and the effect of the modulation ratio on the room-temperature fretting wear (FW) and fretting fatigue (FF) resistance of the alloy was determined. The results indicated that the IAD technique can be successfully used to prepare Cu/Ni multilayer films, with high bonding strength, low-friction, and good toughness, which yield improved room-temperature FF and FW resistance of the alloy. For the same modulation period (200 nm), the micro-hardness, friction, and FW resistance of the coated alloy increased, decreased, and improved, respectively, with increasing modulation ratio of the Ni-to-Cu layer thickness. However, the FF resistance of the coated alloy increased non-monotonically with the increasing modulation ratio. Among the three Cu/Ni multilayer films, those with a modulation ratio of 1:1 can confer the highest FF resistance to the Ti-811 alloy, owing mainly to their unique combination of good toughness, high strength, and low-friction.

Effect of Modulated Alternating and Direct Current Iontophoresis on Transdermal Delivery of Lidocaine Hydrochloride

PubMed Central

Banga, Ajay K.

2014-01-01

The objective of this study was to investigate the iontophoretic delivery of lidocaine hydrochloride through porcine skin and to compare the effects of modulated alternating and direct current iontophoresis. Continuous and modulated iontophoresis was applied for one hour and two hours (0-1 h and 4-5th h) using a 1% w/v solution of lidocaine hydrochloride. Tape stripping was done to quantify the amount of drug permeated into stratum corneum and skin extraction studies were performed to determine the amount of drug in stripped skin. Receptor was sampled and analyzed over predefined time periods. The amount of lidocaine delivered across porcine skin after modulated direct current iontophoresis for 2 h was 1069.87 ± 120.03 μg/sq·cm compared to 744.81 ± 125.41 μg/sq·cm after modulated alternating current iontophoresis for 2 h. Modulated direct current iontophoresis also enhanced lidocaine delivery by twelvefold compared to passive delivery as 91.27 ± 18.71 μg/sq·cm of lidocaine was delivered after passive delivery. Modulated iontophoresis enhanced the delivery of lidocaine hydrochloride across porcine skin compared to the passive delivery. Modulated alternating current iontophoresis for duration of 2 h at frequency of 1 kHz was found to be comparable to the continuous direct current iontophoresis for 1 h. PMID:24959580

The Effect of Modulation Ratio of Cu/Ni Multilayer Films on the Fretting Damage Behaviour of Ti-811 Titanium Alloy

PubMed Central

Zhang, Xiaohua; Liu, Daoxin; Li, Xiaoying; Dong, Hanshan; Xi, Yuntao

2017-01-01

To improve the fretting damage (fretting wear and fretting fatigue) resistance of Ti-811 titanium alloy, three Cu/Ni multilayer films with the same modulation period thickness (200 nm) and different modulation ratios (3:1, 1:1, 1:3) were deposited on the surface of the alloy via ion-assisted magnetron sputtering deposition (IAD). The bonding strength, micro-hardness, and toughness of the films were evaluated, and the effect of the modulation ratio on the room-temperature fretting wear (FW) and fretting fatigue (FF) resistance of the alloy was determined. The results indicated that the IAD technique can be successfully used to prepare Cu/Ni multilayer films, with high bonding strength, low-friction, and good toughness, which yield improved room-temperature FF and FW resistance of the alloy. For the same modulation period (200 nm), the micro-hardness, friction, and FW resistance of the coated alloy increased, decreased, and improved, respectively, with increasing modulation ratio of the Ni-to-Cu layer thickness. However, the FF resistance of the coated alloy increased non-monotonically with the increasing modulation ratio. Among the three Cu/Ni multilayer films, those with a modulation ratio of 1:1 can confer the highest FF resistance to the Ti-811 alloy, owing mainly to their unique combination of good toughness, high strength, and low-friction. PMID:28772947

Effect of modulated alternating and direct current iontophoresis on transdermal delivery of lidocaine hydrochloride.

PubMed

Bhatia, Gaurav; Banga, Ajay K

2014-01-01

The objective of this study was to investigate the iontophoretic delivery of lidocaine hydrochloride through porcine skin and to compare the effects of modulated alternating and direct current iontophoresis. Continuous and modulated iontophoresis was applied for one hour and two hours (0-1 h and 4-5th h) using a 1% w/v solution of lidocaine hydrochloride. Tape stripping was done to quantify the amount of drug permeated into stratum corneum and skin extraction studies were performed to determine the amount of drug in stripped skin. Receptor was sampled and analyzed over predefined time periods. The amount of lidocaine delivered across porcine skin after modulated direct current iontophoresis for 2 h was 1069.87 ± 120.03 μ g/sq · cm compared to 744.81 ± 125.41 μ g/sq · cm after modulated alternating current iontophoresis for 2 h. Modulated direct current iontophoresis also enhanced lidocaine delivery by twelvefold compared to passive delivery as 91.27 ± 18.71 μ g/sq · cm of lidocaine was delivered after passive delivery. Modulated iontophoresis enhanced the delivery of lidocaine hydrochloride across porcine skin compared to the passive delivery. Modulated alternating current iontophoresis for duration of 2 h at frequency of 1 kHz was found to be comparable to the continuous direct current iontophoresis for 1 h.

Design and Analysis of the International X-Ray Observatory Mirror Modules

NASA Technical Reports Server (NTRS)

McClelland, Ryan S.; Carnahan, Timothy M.; Robinson, David W.; Saha, Timo T.

2009-01-01

The Soft X-Ray Telescope (SXT) modules are the fundamental focusing assemblies on NASA's next major X-ray telescope mission, the International X-Ray Observatory (IXO). The preliminary design and analysis of these assemblies has been completed, addressing the major engineering challenges and leading to an understanding of the factors effecting module performance. Each of the 60 modules in the Flight Mirror Assembly (FMA) supports 200-300 densely packed 0.4 mm thick glass mirror segments in order to meet the unprecedented effective area required to achieve the scientific objectives of the mission. Detailed Finite Element Analysis (FEA), materials testing, and environmental testing have been completed to ensure the modules can be successfully launched. Resulting stress margins are positive based on detailed FEA, a large factor of safety, and a design strength determined by robust characterization of the glass properties. FEA correlates well with the results of the successful modal, vibration, and acoustic environmental tests. Deformation of the module due to on-orbit thermal conditions is also a major design driver. A preliminary thermal control system has been designed and the sensitivity of module optical performance to various thermal loads has been determined using optomechanical analysis methods developed for this unique assembly. This design and analysis furthers the goal of building a module that demonstrates the ability to meet IXO requirements, which is the current focus of the IXO FMA technology development team.

Modulation of additive and interactive effects in lexical decision by trial history.

PubMed

Masson, Michael E J; Kliegl, Reinhold

2013-05-01

Additive and interactive effects of word frequency, stimulus quality, and semantic priming have been used to test theoretical claims about the cognitive architecture of word-reading processes. Additive effects among these factors have been taken as evidence for discrete-stage models of word reading. We present evidence from linear mixed-model analyses applied to 2 lexical decision experiments indicating that apparent additive effects can be the product of aggregating over- and underadditive interaction effects that are modulated by recent trial history, particularly the lexical status and stimulus quality of the previous trial's target. Even a simple practice effect expressed as improved response speed across trials was powerfully modulated by the nature of the previous target item. These results suggest that additivity and interaction between factors may reflect trial-to-trial variation in stimulus representations and decision processes rather than fundamental differences in processing architecture.

Preclinical to Human Translational Pharmacology of the Novel M1 Positive Allosteric Modulator MK-7622.

PubMed

Uslaner, Jason M; Kuduk, Scott D; Wittmann, Marion; Lange, Henry S; Fox, Steve V; Min, Chris; Pajkovic, Natasa; Harris, Dawn; Cilissen, Caroline; Mahon, Chantal; Mostoller, Kate; Warrington, Steve; Beshore, Douglas C

2018-06-01

The current standard of care for treating Alzheimer's disease is acetylcholinesterase inhibitors, which nonselectively increase cholinergic signaling by indirectly enhancing activity of nicotinic and muscarinic receptors. These drugs improve cognitive function in patients, but also produce unwanted side effects that limit their efficacy. In an effort to selectively improve cognition and avoid the cholinergic side effects associated with the standard of care, various efforts have been aimed at developing selective M 1 muscarinic receptor activators. In this work, we describe the preclinical and clinical pharmacodynamic effects of the M 1 muscarinic receptor-positive allosteric modulator, MK-7622. MK-7622 attenuated the cognitive-impairing effects of the muscarinic receptor antagonist scopolamine and altered quantitative electroencephalography (qEEG) in both rhesus macaque and human. For both scopolamine reversal and qEEG, the effective exposures were similar between species. However, across species the minimum effective exposures to attenuate the scopolamine impairment were lower than for qEEG. Additionally, there were differences in the spectral power changes produced by MK-7622 in rhesus versus human. In sum, these results are the first to demonstrate translation of preclinical cognition and target modulation to clinical effects in humans for a selective M 1 muscarinic receptor-positive allosteric modulator. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

Development of Mirror Modules for the ART-XC Instrument aboard the Spectrum-Roentgen-Gamma Mission

NASA Technical Reports Server (NTRS)

Gubarev, Mikhail V.; Ramsey, Brian; O'Dell, Stephen L.; Elsner, Ronald F.; Kilaru, Kiranmayee; Atkins, Carolyn; Pavlinskiy, Mikhail N.; Tkachenko, Alexey V.; Lapshov, Igor Y.

2013-01-01

The Marshall Space Flight Center (MSFC) is developing x-ray mirror modules for the Astronomical Roengen Telescope- X-ray Concentrator (ART-XC) instrument on board the Spectrum-Roentgen-Gamma Mission. ART-XC will consist of seven co-aligned x-ray mirror modules with seven corresponding CdTe focal plane detectors. Each module provides an effective area of 65 sq cm at 8 keV, response out to 30 keV, and an angular resolution of 45 arcsec or better HPD. We will present a status of the ART x-ray module development at MSFC.

Reconfigurable WDM-PON empowered by a low-cost 8-channel directly modulated laser module

NASA Astrophysics Data System (ADS)

Zhang, Yi-ming; Liu, Yu; Zhang, Zhi-ke; Zhao, Ze-ping; Tian, Ye; Zhu, Ning-hua

2017-11-01

A 10 Gbit/s 16-km-long reconfigurable wavelength-division-multiplexing passive optical network (WDM-PON) is presented empowered by a low-cost multi-channel directly modulated laser (DML) module. Compared with the case using discrete devices in conventional scheme, the proposed DML module provides a cost-effective solution with reduced complexity. The clear eye diagram and the bit error rate ( BER) of less than 2×10-7 with a sensitivity of -7 dBm are obtained. Due to the special packaging design, the crosstalk between channels under condition of simultaneous operation can be negligible.

Dependence of CdTe response of bias history

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sites, J.R.; Sasala, R.A.; Eisgruber, I.L.

1995-11-01

Several time-dependent effect have been observed in CdTe cells and modules in recent years. Some appear to be related to degradation at the back contact, some to changes in temperature at the thin-film junction, and some to the bias history of the cell or module. Back-contact difficulties only occur in some cases, and the other two effects are reversible. Nevertheless, confusion in data interpretation can arise when these effects are not characterized. This confusion can be particularly acute when more than one time-dependent effect occurs during the same measurement cycle. The purpose of this presentation is to help categorize time-dependentmore » effects in CdTe and other thin-film cells to elucidate those related to bias history, and to note differences between cell and module analysis.« less

Effects of expectation congruency on event-related potentials (ERPs) to facial expressions depend on cognitive load during the expectation phase.

PubMed

Lin, Huiyan; Schulz, Claudia; Straube, Thomas

2016-10-01

Previous studies have shown that event-related potentials (ERPs) to facial expressions are modulated by expectation (congruency) and that the ERP effects of expectation congruency are altered by cognitive tasks during the expectation phase. However, it is as yet unknown whether the congruency ERP effects can be modulated by the amount of cognitive load during the expectation phase. To address this question, electroencephalogram (EEG) was acquired when participants viewed fearful and neutral facial expressions. Before the presentation of facial expressions, a cue indicating the expression of a face and subsequently, an expectation interval without any cues were presented. Facial expressions were congruent with the cues in 75% of all trials. During the expectation interval, participants had to solve a cognitive task, in which several letters were presented for target letter detection. The letters were all the same under low load, but differed under high load. Event-related potential (ERP) results showed that the amount of cognitive load during the expectation phase altered the congruency effect in N2 and EPN amplitudes for fearful faces. Congruent as compared to incongruent fearful expressions elicited larger N2 and smaller EPN amplitudes under low load, but these congruency effects were not observed under high load. For neutral faces, a congruency effect in late positive potential (LPP) amplitudes was modulated by cognitive load during the expectation phase. The LPP was more positive for incongruent as compared to congruent faces under low load, but the congruency effect was not evident under high load. The findings indicate that congruency effects on ERPs are modulated by the amount of cognitive load the expectation phase and that this modulation is altered by facial expression. Copyright © 2016 Elsevier B.V. All rights reserved.

A wide-angle camera module for disposable endoscopy

NASA Astrophysics Data System (ADS)

Shim, Dongha; Yeon, Jesun; Yi, Jason; Park, Jongwon; Park, Soo Nam; Lee, Nanhee

2016-08-01

A wide-angle miniaturized camera module for disposable endoscope is demonstrated in this paper. A lens module with 150° angle of view (AOV) is designed and manufactured. All plastic injection-molded lenses and a commercial CMOS image sensor are employed to reduce the manufacturing cost. The image sensor and LED illumination unit are assembled with a lens module. The camera module does not include a camera processor to further reduce its size and cost. The size of the camera module is 5.5 × 5.5 × 22.3 mm3. The diagonal field of view (FOV) of the camera module is measured to be 110°. A prototype of a disposable endoscope is implemented to perform a pre-clinical animal testing. The esophagus of an adult beagle dog is observed. These results demonstrate the feasibility of a cost-effective and high-performance camera module for disposable endoscopy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernandez-Gutierrez, Sulmer, E-mail: sulmer.a.fernandez.gutierrez@intel.com; Browning, Jim; Lin, Ming-Chieh

Phase-control of a magnetron is studied via simulation using a combination of a continuous current source and a modulated current source. The addressable, modulated current source is turned ON and OFF at the magnetron operating frequency in order to control the electron injection and the spoke phase. Prior simulation work using a 2D model of a Rising Sun magnetron showed that the use of 100% modulated current controlled the magnetron phase and allowed for dynamic phase control. In this work, the minimum fraction of modulated current source needed to achieve a phase control is studied. The current fractions (modulated versusmore » continuous) were varied from 10% modulated current to 100% modulated current to study the effects on phase control. Dynamic phase-control, stability, and start up time of the device were studied for all these cases showing that with 10% modulated current and 90% continuous current, a phase shift of 180° can be achieved demonstrating dynamic phase control.« less

Kilohertz binary phase modulator for pulsed laser sources using a digital micromirror device.

PubMed

Hoffmann, Maximilian; Papadopoulos, Ioannis N; Judkewitz, Benjamin

2018-01-01

The controlled modulation of an optical wavefront is required for aberration correction, digital phase conjugation, or patterned photostimulation. For most of these applications, it is desirable to control the wavefront modulation at the highest rates possible. The digital micromirror device (DMD) presents a cost-effective solution to achieve high-speed modulation and often exceeds the speed of the more conventional liquid crystal spatial light modulator but is inherently an amplitude modulator. Furthermore, spatial dispersion caused by DMD diffraction complicates its use with pulsed laser sources, such as those used in nonlinear microscopy. Here we introduce a DMD-based optical design that overcomes these limitations and achieves dispersion-free high-speed binary phase modulation. We show that this phase modulation can be used to switch through binary phase patterns at the rate of 20 kHz in two-photon excitation fluorescence applications.

Kilohertz binary phase modulator for pulsed laser sources using a digital micromirror device

NASA Astrophysics Data System (ADS)

Hoffmann, Maximilian; Papadopoulos, Ioannis N.; Judkewitz, Benjamin

2018-01-01

The controlled modulation of an optical wavefront is required for aberration correction, digital phase conjugation or patterned photostimulation. For most of these applications it is desirable to control the wavefront modulation at the highest rates possible. The digital micromirror device (DMD) presents a cost-effective solution to achieve high-speed modulation and often exceeds the speed of the more conventional liquid crystal spatial light modulator, but is inherently an amplitude modulator. Furthermore, spatial dispersion caused by DMD diffraction complicates its use with pulsed laser sources, such as those used in nonlinear microscopy. Here we introduce a DMD-based optical design that overcomes these limitations and achieves dispersion-free high-speed binary phase modulation. We show that this phase modulation can be used to switch through binary phase patterns at the rate of 20 kHz in two-photon excitation fluorescence applications.

Photo-induced spatial modulation of THz waves: opportunities and limitations.

PubMed

Kannegulla, Akash; Shams, Md Itrat Bin; Liu, Lei; Cheng, Li-Jing

2015-12-14

Programmable conductive patterns created by photoexcitation of semiconductor substrates using digital light processing (DLP) provides a versatile approach for spatial and temporal modulation of THz waves. The reconfigurable nature of the technology has great potential in implementing several promising THz applications, such as THz beam steering, THz imaging or THz remote sensing, in a simple, cost-effective manner. In this paper, we provide physical insight about how the semiconducting materials, substrate dimension, optical illumination wavelength and illumination size impact the performance of THz modulation, including modulation depth, modulation speed and spatial resolution. The analysis establishes design guidelines for the development of photo-induced THz modulation technology. Evolved from the theoretical analysis, a new mesa array technology composed by a matrix of sub-THz wavelength structures is introduced to maximize both spatial resolution and modulation depth for THz modulation with low-power photoexcitation by prohibiting the lateral diffusion of photogenerated carriers.

The effects of control field detuning on the modulation instability in a three-level quantum well system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borgohain, Nitu, E-mail: nituborgohain.ism@gmail.com; Konar, S.

The paper presents a theoretical study of the modulation instability of a continuous or quasi-continuous optical probe in a three level quantum well system under electromagnetically induced transparency. The modulation instability is affected by the control field detuning, as well as even-order dispersion and by the strength of Kerr (third-order) and quintic (fifth-order) nonlinearities. The fourth-order dispersion reduces the bandwidth over which modulation instability occurs, whereas the quintic nonlinearity saturates the growth of the modulation instability. Detuning the control field from resonance can significantly reduce the growth of the modulation instability at both low and high power levels. At lowmore » powers, the system becomes stable against modulation instability for small detuning of the control field and at high powers modulation instability disappears for larger detuning.« less

Computer-Assisted Instruction in the Context of the Advanced Instructional System. Part II. Materials Development Procedures and System Evaluation.

DTIC Science & Technology

1980-03-01

authoring system which would provide a basis for the cost effective production of computer-assisted irstruction (CAI) materials, It addresses the definition...RESULTS- - ------------------- 58 CAI Materials Development Times - - - 5J CAI Module Instructional Effectiveness -------- -- 59 First-Pass Module...CONCLUSIONS AND RECOMMENDATIONS ------ --- -- -- 70 Effectiveness of the Authoring System and Suggestions for Further Development - ----- --- -- --- 70

Effective Classroom Management. The Basic Element of Effective Teaching. A Module for Undergraduate Instruction in Teacher Education in the RAFT Program at Mississippi State University.

ERIC Educational Resources Information Center

Handley, Herbert M., Ed.

This module, developed by the Research Applications for Teaching (RAFT) project, introduces the undergraduate student to practices of teachers in effective schools which facilitate the climate for learning in the classroom. Used with Canter's materials on assertive discipline, the preservice teachers should have an opportunity to reflect carefully…

Impingement effect of service module reaction control system engine plumes. Results of service module reaction control system plume model force field application to an inflight Skylab mission proximity operation situation with the inflight Skylab response

NASA Technical Reports Server (NTRS)

Lobb, J. D., Jr.

1978-01-01

Plume impingement effects of the service module reaction control system thruster firings were studied to determine if previous flight experience would support the current plume impingement model for the orbiter reaction control system engines. The orbiter reaction control system is used for rotational and translational maneuvers such as those required during rendezvous, braking, docking, and station keeping. Therefore, an understanding of the characteristics and effects of the plume force fields generated by the reaction control system thruster firings were examined to develop the procedures for orbiter/payload proximity operations.

The effectiveness of module based on guided inquiry method to improve students’ logical thinking ability

NASA Astrophysics Data System (ADS)

Ash-Shiddieqy, M. H.; Suparmi, A.; Sunarno, W.

2018-04-01

The purpose of this research is to understand the effectiveness of module based on guided inquiry method to improve students’ logical thinking ability. This research only evaluate the students’ logical ability after follows the learning activities that used developed physics module based on guided inquiry method. After the learning activities, students This research method uses a test instrument that adapts TOLT instrument. There are samples of 68 students of grade XI taken from SMA Negeri 4 Surakarta.Based on the results of the research can be seen that in the experimental class and control class, the posttest value aspect of probabilistic reasoning has the highest value than other aspects, whereas the posttest value of the proportional reasoning aspect has the lowest value. The average value of N-gain in the experimental class is 0.39, while in the control class is 0.30. Nevertheless, the N-gain values obtained in the experimental class are larger than the control class, so the guided inquiry-based module is considered more effective for improving students’ logical thinking. Based on the data obtained from the research shows the modules available to help teachers and students in learning activities. The developed Physics module is integrated with every syntax present in guided inquiry method, so it can be used to improve students’ logical thinking ability.

Gastrointestinal Transit Time, Glucose Homeostasis and Metabolic Health: Modulation by Dietary Fibers

PubMed Central

Müller, Mattea; Canfora, Emanuel E.; Blaak, Ellen E.

2018-01-01

Gastrointestinal transit time may be an important determinant of glucose homeostasis and metabolic health through effects on nutrient absorption and microbial composition, among other mechanisms. Modulation of gastrointestinal transit may be one of the mechanisms underlying the beneficial health effects of dietary fibers. These effects include improved glucose homeostasis and a reduced risk of developing metabolic diseases such as obesity and type 2 diabetes mellitus. In this review, we first discuss the regulation of gastric emptying rate, small intestinal transit and colonic transit as well as their relation to glucose homeostasis and metabolic health. Subsequently, we briefly address the reported health effects of different dietary fibers and discuss to what extent the fiber-induced health benefits may be mediated through modulation of gastrointestinal transit. PMID:29495569

The all-optical modulator in dielectric-loaded waveguide with graphene-silicon heterojunction structure

NASA Astrophysics Data System (ADS)

Sun, Feiying; Xia, Liangping; Nie, Changbin; Shen, Jun; Zou, Yixuan; Cheng, Guiyu; Wu, Hao; Zhang, Yong; Wei, Dongshan; Yin, Shaoyun; Du, Chunlei

2018-04-01

All-optical modulators based on graphene show great promise for on-chip optical interconnects. However, the modulation performance of all-optical modulators is usually based on the interaction between graphene and the fiber, limiting their potential in high integration. Based on this point, an all-optical modulator in a dielectric-loaded waveguide (DLW) with a graphene-silicon heterojunction structure (GSH) is proposed. The DLW raises the waveguide mode, which provides a strong light-graphene interaction. Sufficient tuning of the graphene Fermi energy beyond the Pauli blocking effect is obtained with the presented GSH structure. Under the modulation light with a wavelength of 532 nm and a power of 60 mW, a modulation efficiency of 0.0275 dB µm-1 is achieved for light with a communication wavelength of 1.55 µm in the experiment. This modulator has the advantage of having a compact footprint, which may make it a candidate for achieving a highly integrated all-optical modulator.

Development of Mirror Modules for the ART-XC Instrument aboard the Spectrum-Roentgen-Gamma Mission

NASA Technical Reports Server (NTRS)

Gubarev, M; Ramsey, B.; O'Dell, S. L.; Elsner, R.; Kilaru, K.; McCracken, J.; Pavlinsky, M.; Tkachenko, A.; Lapshov, I.; Atkins, C.;

Development of mirror modules for the ART-XC instrument aboard the Spectrum-Roentgen-Gamma mission

NASA Astrophysics Data System (ADS)

Gubarev, M.; Ramsey, B.; O'Dell, S. L.; Elsner, R.; Kilaru, K.; McCracken, J.; Pavlinsky, M.; Tkachenko, A.; Lapshov, I.; Atkins, C.; Zavlin, V.

2013-09-01

The Marshall Space Flight Center (MSFC) is developing x-ray mirror modules for the ART-XC instrument on board the Spectrum-Roentgen Gamma Mission. Four of those modules are being fabricated under a Reimbursable Agreement between NASA and the Russian Space Research Institute (IKI.) An additional three flight modules and one spare for the ART-XC Instrument are produced under a Cooperative Agreement between NASA and IKI. The instrument will consist of seven co-aligned x-ray mirror modules with seven corresponding CdTe focal plane detectors. Each module consists of 28 nested thin Ni/Co shells giving an effective area of 65 cm2 at 8 keV, response out to 30 keV, and an angular resolution of 45 arcsec or better HPD. Delivery of the first four modules is scheduled for November 2013, while the remaining three modules will be delivered to IKI in January 2014. We present a status of the ART x-ray module development at MSFC.

Responses to amplitude modulated infrared stimuli in the guinea pig inferior colliculus

NASA Astrophysics Data System (ADS)

Richter, Claus-Peter; Young, Hunter

2013-03-01

Responses of units in the central nucleus of the inferior colliculus of the guinea pig were recorded with tungsten electrodes. The set of data presented here is limited to high stimulus levels. The effect of changing the modulation frequency and the modulation depth was explored for acoustic and laser stimuli. The selected units responded to sinusoidal amplitude modulated (AM) tones, AM trains of clicks, and AM trains of laser pulses with a modulation of their spike discharge. At modulation frequencies of 20 Hz, some units tended to respond with 40 Hz to the acoustic stimuli, but only at 20 Hz for the trains of laser pulses. For all modes of stimulation the responses revealed a dominant response to the first cycle of the modulation, with decreasing number of action potential during successive cycles. While amplitude modulated tone bursts and amplitude modulated trains of acoustic clicks showed similar patterns, the response to trains of laser pulses was different.

Cystic Fibrosis Transmembrane Regulator Modulators: Implications for the Management of Depression and Anxiety in Cystic Fibrosis.

PubMed

Talwalkar, Jaideep S; Koff, Jonathan L; Lee, Hochang B; Britto, Clemente J; Mulenos, Arielle M; Georgiopoulos, Anna M

Individuals with cystic fibrosis (CF) are at high risk for depression and anxiety, which are associated with worse medical outcomes. Novel therapies for CF hold great promise for improving physical health, but the effects of these therapies on mental health remain poorly understood. This review aims to familiarize psychiatrists with the potential effect of novel CF therapies on depression and anxiety. We discuss novel therapies that directly target the mutant CF protein, the CF transmembrane regulator (CFTR), which are called CFTR modulators. We summarize depression and anxiety screening and treatment guidelines under implementation in accredited CF centers. Case vignettes highlight the complexities of caring for individuals with CF with comorbid depression and anxiety, including patients experiencing worsening depression and anxiety proximate to initiation of CFTR modulator therapy, and management of drug-drug interactions. Although CFTR modulator therapies provide hope for improving clinical outcomes, worsening depression and anxiety occurs in some patients when starting these novel agents. This phenomenon may be multifactorial, with hypothesized contributions from CFTR modulator-psychotropic medication interactions, direct effects of CFTR modulators on central nervous system function, the psychologic effect of starting a potentially life-altering drug, and typical triggers of depression and anxiety such as stress, pain, and inflammation. The medical and psychiatric complexity of many individuals with CF warrants more direct involvement of mental health specialists on the multidisciplinary CF team. Inclusion of mental health variables in patients with CF registries will facilitate further examination at an epidemiologic level. Copyright © 2017 The Academy of Psychosomatic Medicine. Published by Elsevier Inc. All rights reserved.

MEG evidence that the central auditory system simultaneously encodes multiple temporal cues.

PubMed

Simpson, Michael I G; Barnes, Gareth R; Johnson, Sam R; Hillebrand, Arjan; Singh, Krish D; Green, Gary G R

2009-09-01

Speech contains complex amplitude modulations that have envelopes with multiple temporal cues. The processing of these complex envelopes is not well explained by the classical models of amplitude modulation processing. This may be because the evidence for the models typically comes from the use of simple sinusoidal amplitude modulations. In this study we used magnetoencephalography (MEG) to generate source space current estimates of the steady-state responses to simple one-component amplitude modulations and to a two-component amplitude modulation. A two-component modulation introduces the simplest form of modulation complexity into the waveform; the summation of the two-modulation rates introduces a beat-like modulation at the difference frequency between the two modulation rates. We compared the cortical representations of responses to the one-component and two-component modulations. In particular, we show that the temporal complexity in the two-component amplitude modulation stimuli was preserved at the cortical level. The method of stimulus normalization that we used also allows us to interpret these results as evidence that the important feature in sound modulations is the relative depth of one modulation rate with respect to another, rather than the absolute carrier-to-sideband modulation depth. More generally, this may be interpreted as evidence that modulation detection accurately preserves a representation of the modulation envelope. This is an important observation with respect to models of modulation processing, as it suggests that models may need a dynamic processing step to effectively model non-stationary stimuli. We suggest that the classic modulation filterbank model needs to be modified to take these findings into account.

Driving Sodium-Potassium Pumps With An Oscillating Electric Field: Effects On Muscle Recovery In The Human Biceps Brachii

NASA Astrophysics Data System (ADS)

Bovyn, Matt; Chen, Wei; Lanes, Olivia; Mast, Jason

2013-03-01

Dr. Chen has developed a technique called synchronization modulation, which uses an oscillating electric field to increase the rate at which the sodium-potassium pumps in the cell membrane work. Because the sodium-potassium pump is integral in the recovery of skeletal muscle fibers after an action potential, we investigated the effects of applying synchronization modulation to muscles which had already undergone fatigue due to repeated action potentials during exercise. Fatigue was induced in human subjects' biceps brachii through isometric contraction. Surface electromyography measurements of fatigue index were used to quantify how the muscle recovered over the minutes following fatigue, both when synchronization modulation was applied and when it was absent. The preliminary results were inconclusive, but it is hoped that in later work it will be shown that applying synchronization modulation is effective in increasing the rate at which the muscle recovers to its initial state. This would demonstrate not only that synchronization modulation can be successfully applied to human muscle, but also that it has many potential applications in sports medicine and novel disease treatments. Work done as part of an REU program at the University of South Florida

Obliquity Modulation of the Incoming Solar Radiation

NASA Technical Reports Server (NTRS)

Liu, Han-Shou; Smith, David E. (Technical Monitor)

2001-01-01

Based on a basic principle of orbital resonance, we have identified a huge deficit of solar radiation induced by the combined amplitude and frequency modulation of the Earth's obliquity as possibly the causal mechanism for ice age glaciation. Including this modulation effect on solar radiation, we have performed model simulations of climate change for the past 2 million years. Simulation results show that: (1) For the past 1 million years, temperature fluctuation cycles were dominated by a 100-Kyr period due to amplitude-frequency resonance effect of the obliquity; (2) From 2 to 1 million years ago, the amplitude-frequency interactions. of the obliquity were so weak that they were not able to stimulate a resonance effect on solar radiation; (3) Amplitude and frequency modulation analysis on solar radiation provides a series of resonance in the incoming solar radiation which may shift the glaciation cycles from 41-Kyr to 100-Kyr about 0.9 million years ago. These results are in good agreement with the marine and continental paleoclimate records. Thus, the proposed climate response to the combined amplitude and frequency modulation of the Earth's obliquity may be the key to understanding the glaciation puzzles in paleoclimatology.

Curcumin mediates anticancer effects by modulating multiple cell signaling pathways.

PubMed

Kunnumakkara, Ajaikumar B; Bordoloi, Devivasha; Harsha, Choudhary; Banik, Kishore; Gupta, Subash C; Aggarwal, Bharat B

2017-08-01

Curcumin, a component of a spice native to India, was first isolated in 1815 by Vogel and Pelletier from the rhizomes of Curcuma longa (turmeric) and, subsequently, the chemical structure of curcumin as diferuloylmethane was reported by Milobedzka et al. [(1910) 43., 2163-2170]. Since then, this polyphenol has been shown to exhibit antioxidant, anti-inflammatory, anticancer, antiviral, antibacterial, and antifungal activities. The current review primarily focuses on the anticancer potential of curcumin through the modulation of multiple cell signaling pathways. Curcumin modulates diverse transcription factors, inflammatory cytokines, enzymes, kinases, growth factors, receptors, and various other proteins with an affinity ranging from the pM to the mM range. Furthermore, curcumin effectively regulates tumor cell growth via modulation of numerous cell signaling pathways and potentiates the effect of chemotherapeutic agents and radiation against cancer. Curcumin can interact with most of the targets that are modulated by FDA-approved drugs for cancer therapy. The focus of this review is to discuss the molecular basis for the anticancer activities of curcumin based on preclinical and clinical findings. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Low heart rate variability in unemployed men: The possible mediating effects of life satisfaction.

PubMed

Jandackova, V K; Jackowska, M

2015-01-01

Unemployment has consistently been associated with increased risk of cardiovascular disease and premature mortality, and impaired autonomic modulation of the heart might be one mechanism partly explaining this. This study examined whether the possible effect of unemployment on cardiac autonomic modulation is in part mediated by lower psychological well-being. The sample comprised of 15 job-seeking men aged 30-49 years matched with 15 employed men on age, type of job, smoking habits, alcohol intake, frequency of physical activity, and body mass index. Heart rate variability (HRV) during a modified orthostatic test was the measure of cardiac autonomic modulation, and life satisfaction was the measure of psychological well-being. Unemployed men had significantly lower overall HRV (p = .040) than controls. This association was partially mediated through lower general life satisfaction, and in particular, by low financial satisfaction, independently of demographic and/or behavioral factors that influence HRV. These findings suggest that seeking a job is a potential stressor that may reduce overall HRV and contribute towards disturbance of cardiac autonomic modulation in men. Financial difficulties could be one mechanism through which the effects of unemployment are translated into impaired autonomic modulation.

Strain Modulations as a Mechanism to Reduce Stress Relaxation in Laryngeal Tissues

PubMed Central

Hunter, Eric J.; Siegmund, Thomas; Chan, Roger W.

2014-01-01

Vocal fold tissues in animal and human species undergo deformation processes at several types of loading rates: a slow strain involved in vocal fold posturing (on the order of 1 Hz or so), cyclic and faster posturing often found in speech tasks or vocal embellishment (1–10 Hz), and shear strain associated with vocal fold vibration during phonation (100 Hz and higher). Relevant to these deformation patterns are the viscous properties of laryngeal tissues, which exhibit non-linear stress relaxation and recovery. In the current study, a large strain time-dependent constitutive model of human vocal fold tissue is used to investigate effects of phonatory posturing cyclic strain in the range of 1 Hz to 10 Hz. Tissue data for two subjects are considered and used to contrast the potential effects of age. Results suggest that modulation frequency and extent (amplitude), as well as the amount of vocal fold overall strain, all affect the change in stress relaxation with modulation added. Generally, the vocal fold cover reduces the rate of relaxation while the opposite is true for the vocal ligament. Further, higher modulation frequencies appear to reduce the rate of relaxation, primarily affecting the ligament. The potential benefits of cyclic strain, often found in vibrato (around 5 Hz modulation) and intonational inflection, are discussed in terms of vocal effort and vocal pitch maintenance. Additionally, elderly tissue appears to not exhibit these benefits to modulation. The exacerbating effect such modulations may have on certain voice disorders, such as muscle tension dysphonia, are explored. PMID:24614616

Modulation of neuronal responses during covert search for visual feature conjunctions

PubMed Central

Buracas, Giedrius T.; Albright, Thomas D.

2009-01-01

While searching for an object in a visual scene, an observer's attentional focus and eye movements are often guided by information about object features and spatial locations. Both spatial and feature-specific attention are known to modulate neuronal responses in visual cortex, but little is known of the dynamics and interplay of these mechanisms as visual search progresses. To address this issue, we recorded from directionally selective cells in visual area MT of monkeys trained to covertly search for targets defined by a unique conjunction of color and motion features and to signal target detection with an eye movement to the putative target. Two patterns of response modulation were observed. One pattern consisted of enhanced responses to targets presented in the receptive field (RF). These modulations occurred at the end-stage of search and were more potent during correct target identification than during erroneous saccades to a distractor in RF, thus suggesting that this modulation is not a mere presaccadic enhancement. A second pattern of modulation was observed when RF stimuli were nontargets that shared a feature with the target. The latter effect was observed during early stages of search and is consistent with a global feature-specific mechanism. This effect often terminated before target identification, thus suggesting that it interacts with spatial attention. This modulation was exhibited not only for motion but also for color cue, although MT neurons are known to be insensitive to color. Such cue-invariant attentional effects may contribute to a feature binding mechanism acting across visual dimensions. PMID:19805385

Modulation of neuronal responses during covert search for visual feature conjunctions.

PubMed

Buracas, Giedrius T; Albright, Thomas D

2009-09-29

While searching for an object in a visual scene, an observer's attentional focus and eye movements are often guided by information about object features and spatial locations. Both spatial and feature-specific attention are known to modulate neuronal responses in visual cortex, but little is known of the dynamics and interplay of these mechanisms as visual search progresses. To address this issue, we recorded from directionally selective cells in visual area MT of monkeys trained to covertly search for targets defined by a unique conjunction of color and motion features and to signal target detection with an eye movement to the putative target. Two patterns of response modulation were observed. One pattern consisted of enhanced responses to targets presented in the receptive field (RF). These modulations occurred at the end-stage of search and were more potent during correct target identification than during erroneous saccades to a distractor in RF, thus suggesting that this modulation is not a mere presaccadic enhancement. A second pattern of modulation was observed when RF stimuli were nontargets that shared a feature with the target. The latter effect was observed during early stages of search and is consistent with a global feature-specific mechanism. This effect often terminated before target identification, thus suggesting that it interacts with spatial attention. This modulation was exhibited not only for motion but also for color cue, although MT neurons are known to be insensitive to color. Such cue-invariant attentional effects may contribute to a feature binding mechanism acting across visual dimensions.

Polysaccharides from Ganoderma lucidum attenuate microglia-mediated neuroinflammation and modulate microglial phagocytosis and behavioural response.

PubMed

Cai, Qing; Li, Yuanyuan; Pei, Gang

2017-03-24

Ganoderma lucidum (GL) has been widely used in Asian countries for hundreds of years to promote health and longevity. The pharmacological functions of which had been classified, including the activation of innate immune responses, suppression of tumour and modulation of cell proliferations. Effective fractions of Ganoderma lucidum polysaccharides (GLP) had already been reported to regulate the immune system. Nevertheless, the role of GLP in the microglia-mediated neuroinflammation has not been sufficiently elucidated. Further, GLP effect on microglial behavioural modulations in correlation with the inflammatory responses remains to be unravelled. The aim of this work was to quantitatively analyse the contributions of GLP on microglia. The BV2 microglia and primary mouse microglia were stimulated by lipopolysaccharides (LPS) and amyloid beta 42 (Aβ 42 ) oligomer, respectively. Investigation on the effect of GLP was carried by quantitative determination of the microglial pro- and anti-inflammatory cytokine expressions and behavioural modulations including migration, morphology and phagocytosis. Analysis of microglial morphology and phagocytosis modulations was confirmed in the zebrafish brain. Quantitative results revealed that GLP down-regulates LPS- or Aβ-induced pro-inflammatory cytokines and promotes anti-inflammatory cytokine expressions in BV-2 and primary microglia. In addition, GLP attenuates inflammation-related microglial migration, morphological alterations and phagocytosis probabilities. We also showed that modulations of microglial behavioural responses were associated with MCP-1 and C1q expressions. Overall, our study provides an insight into the GLP regulation of LPS- and Aβ-induced neuroinflammation and serves an implication that the neuroprotective function of GLP might be achieved through modulation of microglial inflammatory and behavioural responses.

Strain modulations as a mechanism to reduce stress relaxation in laryngeal tissues.

PubMed

Hunter, Eric J; Siegmund, Thomas; Chan, Roger W

2014-01-01

Vocal fold tissues in animal and human species undergo deformation processes at several types of loading rates: a slow strain involved in vocal fold posturing (on the order of 1 Hz or so), cyclic and faster posturing often found in speech tasks or vocal embellishment (1-10 Hz), and shear strain associated with vocal fold vibration during phonation (100 Hz and higher). Relevant to these deformation patterns are the viscous properties of laryngeal tissues, which exhibit non-linear stress relaxation and recovery. In the current study, a large strain time-dependent constitutive model of human vocal fold tissue is used to investigate effects of phonatory posturing cyclic strain in the range of 1 Hz to 10 Hz. Tissue data for two subjects are considered and used to contrast the potential effects of age. Results suggest that modulation frequency and extent (amplitude), as well as the amount of vocal fold overall strain, all affect the change in stress relaxation with modulation added. Generally, the vocal fold cover reduces the rate of relaxation while the opposite is true for the vocal ligament. Further, higher modulation frequencies appear to reduce the rate of relaxation, primarily affecting the ligament. The potential benefits of cyclic strain, often found in vibrato (around 5 Hz modulation) and intonational inflection, are discussed in terms of vocal effort and vocal pitch maintenance. Additionally, elderly tissue appears to not exhibit these benefits to modulation. The exacerbating effect such modulations may have on certain voice disorders, such as muscle tension dysphonia, are explored.

Clay Modeling versus Written Modules as Effective Interventions in Understanding Human Anatomy

ERIC Educational Resources Information Center

Bareither, Mary Lou; Arbel, Vered; Growe, Meghan; Muszczynski, Emily; Rudd, Adam; Marone, Jane R.

2013-01-01

The effectiveness of clay modeling to written modules is examined to determine the degree of improvement in learning and retention of anatomical 3D relationships among students with different learning preferences. Thirty-nine undergraduate students enrolled in a cadaver dissection course completed a pre-assessment examination and the VARK…

Effects of Agricultural Sales CDE Modules on Content Knowledge and Argumentation Skill

ERIC Educational Resources Information Center

Sapp, Sarah B.; Thoron, Andrew C.

2014-01-01

The purpose of this study was to determine the effects of the type of training module on argumentation skill, student content knowledge achievement, and performance in an agricultural sales practicum completed by secondary school agriculture students. Current research has concluded that most students do not possess the academic or transferable…

Effects of Articulation Styles on Perception of Modulated Tempos in Violin Excerpts

ERIC Educational Resources Information Center

Geringer, John M.; Madsen, Clifford K.; Macleod, Rebecca B.

2007-01-01

We investigated effects of legato, staccato and pizzicato articulation styles on the perception of modulated tempos. Seventy-two music majors served as participants. Two solo violin excerpts were chosen with contrasting rhythmic rates and were recorded in all three articulation styles. Examples were presented to listeners in three conditions of…

The Features of Effective Online Professional Development for Early Childhood Educators

ERIC Educational Resources Information Center

Ascetta, Kate Elisabeth

2017-01-01

The purpose of this current study was to examine the effect of a preschool teacher intervention around the use self-monitoring and the online learning modules. The interventions were delivered online using: online learning modules that provided exemplars of the operationally defined instructional language supports. The study included 12 Head Start…

ENDOCRINE MODULATING EFFECTS OF LAGOON WATER FROM CONFINED ANIMAL FEED OPERATIONS ON AMPHIBIANS

EPA Science Inventory

Endocrine Modulating Effects of Lagoon Water from Confined Animal Feed Operations on Amphibians. Weber, L.P.*1, Dumont, J.N.1, Selcer, K.W.2, Hutchins, S.R.3, and Janz, D.M.1 1Oklahoma State University, Stillwater, OK, 2Duquesne University, Pittsburgh, PA, 3U.S. Environmenta...

Effectiveness of Diversity Infusion Modules on Students' Attitudes, Behavior, and Knowledge

ERIC Educational Resources Information Center

Saleh, Mahasin F.; Anngela-Cole, Linda; Boateng, Alice

2011-01-01

The purpose of this study was to evaluate the effectiveness of diversity infusion modules provided to university students in a predominantly white homogeneous community. A mixed-method approach using a pre-post retrospective design was used to measure attitudes, behaviors, and knowledge about diversity issues, and included a comparison group…

Anthocyanins as inflammatory modulators and the role of the gut microbiota.

PubMed

Morais, Carina Almeida; de Rosso, Veridiana Vera; Estadella, Débora; Pisani, Luciana Pellegrini

2016-07-01

The health benefits of consuming fruits that are rich in polyphenols, especially anthocyanins, have been the focus of recent in vitro and in vivo investigations. Thus, greater attention is being directed to the reduction of the inflammatory process associated with the intestinal microbiota and the mechanism underlying these effects because the microbiota has been closely associated with the metabolism of these compounds in the gastrointestinal tract. Further interest lies in the ability of these metabolites to modulate the growth of specific intestinal bacteria. Thus, this review examines studies involving the action of the anthocyanins that are present in many fruits and their effect in the modulating the inflammatory process associated with the interaction between the host and the gut microbiota. The findings of both in vitro and in vivo studies suggest a potential antiinflammatory effect of these compounds, which seem to inhibit activation of the signaling pathway mediated by the transcription factor NFκB. This effect is associated with modulation of a beneficial gut microbiota, particularly an increase in Bifidobacterium strains. Copyright © 2015 Elsevier Inc. All rights reserved.

Odor Valence Linearly Modulates Attractiveness, but Not Age Assessment, of Invariant Facial Features in a Memory-Based Rating Task

PubMed Central

Seubert, Janina; Gregory, Kristen M.; Chamberland, Jessica; Dessirier, Jean-Marc; Lundström, Johan N.

2014-01-01

Scented cosmetic products are used across cultures as a way to favorably influence one's appearance. While crossmodal effects of odor valence on perceived attractiveness of facial features have been demonstrated experimentally, it is unknown whether they represent a phenomenon specific to affective processing. In this experiment, we presented odors in the context of a face battery with systematic feature manipulations during a speeded response task. Modulatory effects of linear increases of odor valence were investigated by juxtaposing subsequent memory-based ratings tasks – one predominantly affective (attractiveness) and a second, cognitive (age). The linear modulation pattern observed for attractiveness was consistent with additive effects of face and odor appraisal. Effects of odor valence on age perception were not linearly modulated and may be the result of cognitive interference. Affective and cognitive processing of faces thus appear to differ in their susceptibility to modulation by odors, likely as a result of privileged access of olfactory stimuli to affective brain networks. These results are critically discussed with respect to potential biases introduced by the preceding speeded response task. PMID:24874703

Modulation of a compressional electromagnetic wave in a magnetized electron-positron quantum plasma.

PubMed

Amin, M R

2015-09-01

Amplitude modulation of a compressional electromagnetic wave in a strongly magnetized electron-positron pair plasma is considered in the quantum magnetohydrodynamic regime. The important ingredients of this study are the inclusion of the external strong magnetic field, Fermi quantum degeneracy pressure, particle exchange potential, quantum diffraction effects via the Bohm potential, and dissipative effect due to collision of the charged carriers. A modified-nonlinear Schödinger equation is developed for the compressional magnetic field of the electromagnetic wave by employing the standard reductive perturbation technique. The linear and nonlinear dispersions of the electromagnetic wave are discussed in detail. For some parameter ranges, relevant to dense astrophysical objects such as the outer layers of white dwarfs, neutron stars, and magnetars, etc., it is found that the compressional electromagnetic wave is modulationally unstable and propagates as a dissipated electromagnetic wave. It is also found that the quantum effects due to the particle exchange potential and the Bohm potential are negligibly small in comparison to the effects of the Fermi quantum degeneracy pressure. The numerical results on the growth rate of the modulation instability is also presented.

Design strategies to address the effect of hydrophobic epitope on stability and in vitro assembly of modular virus‐like particle

PubMed Central

Tekewe, Alemu; Connors, Natalie K.; Middelberg, Anton P. J.

2016-01-01

Abstract Virus‐like particles (VLPs) and capsomere subunits have shown promising potential as safe and effective vaccine candidates. They can serve as platforms for the display of foreign epitopes on their surfaces in a modular architecture. Depending on the physicochemical properties of the antigenic modules, modularization may affect the expression, solubility and stability of capsomeres, and VLP assembly. In this study, three module designs of a rotavirus hydrophobic peptide (RV10) were synthesized using synthetic biology. Among the three synthetic modules, modularization of the murine polyomavirus VP1 with a single copy of RV10 flanked by long linkers and charged residues resulted in the expression of stable modular capsomeres. Further employing the approach of module titration of RV10 modules on each capsomere via Escherichia coli co‐expression of unmodified VP1 and modular VP1‐RV10 successfully translated purified modular capomeres into modular VLPs when assembled in vitro. Our results demonstrate that tailoring the physicochemical properties of modules to enhance modular capsomeres stability is achievable through synthetic biology designs. Combined with module titration strategy to avoid steric hindrance to intercapsomere interactions, this allows bioprocessing of bacterially produced in vitro assembled modular VLPs. PMID:27222486

Design strategies to address the effect of hydrophobic epitope on stability and in vitro assembly of modular virus-like particle.

PubMed

Tekewe, Alemu; Connors, Natalie K; Middelberg, Anton P J; Lua, Linda H L

2016-08-01

Virus-like particles (VLPs) and capsomere subunits have shown promising potential as safe and effective vaccine candidates. They can serve as platforms for the display of foreign epitopes on their surfaces in a modular architecture. Depending on the physicochemical properties of the antigenic modules, modularization may affect the expression, solubility and stability of capsomeres, and VLP assembly. In this study, three module designs of a rotavirus hydrophobic peptide (RV10) were synthesized using synthetic biology. Among the three synthetic modules, modularization of the murine polyomavirus VP1 with a single copy of RV10 flanked by long linkers and charged residues resulted in the expression of stable modular capsomeres. Further employing the approach of module titration of RV10 modules on each capsomere via Escherichia coli co-expression of unmodified VP1 and modular VP1-RV10 successfully translated purified modular capomeres into modular VLPs when assembled in vitro. Our results demonstrate that tailoring the physicochemical properties of modules to enhance modular capsomeres stability is achievable through synthetic biology designs. Combined with module titration strategy to avoid steric hindrance to intercapsomere interactions, this allows bioprocessing of bacterially produced in vitro assembled modular VLPs. © 2016 The Protein Society.

Modulated and continuous-wave operations of low-power thulium (Tm:YAP) laser in tissue welding

NASA Astrophysics Data System (ADS)

Bilici, Temel; Tabakoğlu, Haşim Özgür; Topaloğlu, Nermin; Kalaycıoğlu, Hamit; Kurt, Adnan; Sennaroglu, Alphan; Gülsoy, Murat

2010-05-01

Our aim is to explore the welding capabilities of a thulium (Tm:YAP) laser in modulated and continuous-wave (CW) modes of operation. The Tm:YAP laser system developed for this study includes a Tm:YAP laser resonator, diode laser driver, water chiller, modulation controller unit, and acquisition/control software. Full-thickness incisions on Wistar rat skin were welded by the Tm:YAP laser system at 100 mW and 5 s in both modulated and CW modes of operation (34.66 W/cm2). The skin samples were examined during a 21-day healing period by histology and tensile tests. The results were compared with the samples closed by conventional suture technique. For the laser groups, immediate closure at the surface layers of the incisions was observed. Full closures were observed for both modulated and CW modes of operation at day 4. The tensile forces for both modulated and CW modes of operation were found to be significantly higher than the values found by conventional suture technique. The 1980-nm Tm:YAP laser system operating in both modulated and CW modes maximizes the therapeutic effect while minimizing undesired side effects of laser tissue welding. Hence, it is a potentially important alternative tool to the conventional suturing technique.

Module 4--Effective Teaching. School Improvement Specialist Training Materials: Performance Standards, Improving Schools, and Literature Review

ERIC Educational Resources Information Center

Appalachia Educational Laboratory at Edvantia (NJ1), 2005

2005-01-01

The School Improvement Specialist Project prepared seven modules. School improvement specialists, as defined by the Appalachia Educational Laboratory at Edvantia, are change agents who work with schools to help them improve in the following areas so as to increase student achievement. These modules are intended to provide training materials for…

Exercising Your Rights: Eliminating Sex Bias in Physical Education.

ERIC Educational Resources Information Center

Campbell, Patricia B.; Katrin, Susan E.

A module on sex stereotyping and its effect on physical education is described. This unit is a part of a series of instructional modules on sex-role stereotyping in education. Designed to be used independently or to supplement an existing instructional unit, the module is composed of a 25-minute tape, five transparency masters, three handouts, and…

Module Five: Relationships of Current, Voltage, and Resistance; Basic Electricity and Electronics Individualized Learning System.

ERIC Educational Resources Information Center

Bureau of Naval Personnel, Washington, DC.

This module covers the relationships between current and voltage; resistance in a series circuit; how to determine the values of current, voltage, resistance, and power in resistive series circuits; the effects of source internal resistance; and an introduction to the troubleshooting of series circuits. This module is divided into five lessons:…

Building Effective Partnerships: A Win-Win Approach. Module II. Job Match: Together for Good Business.

ERIC Educational Resources Information Center

Banzhaf, Katie; And Others

Intended for use with personnel in business, industry, and human service agencies, the training module is part of a kit designed to demonstrate how individuals with disabilities and older persons can be assimilated successfully into the labor force. This module explains partnerships between businesses and human service agencies. It emphasizes the…

Identifying Effective Design Features of Technology-Infused Inquiry Learning Modules: A Two-Year Study of Students' Inquiry Abilities

ERIC Educational Resources Information Center

Hsu, Ying-Shao; Fang, Su-Chi; Zhang, Wen-Xin; Hsin-Kai, Wu; Wu, Pai-Hsing; Hwang, Fu-Kwun

2016-01-01

The two-year study aimed to explore how students' development of different inquiry abilities actually benefited from the design of technology-infused learning modules. Three learning modules on the topics of seasons, environmental issues and air pollution were developed to facilitate students' inquiry abilities: questioning, planning, analyzing,…

Evaluating the Effectiveness of a Practical Inquiry-Based Learning Bioinformatics Module on Undergraduate Student Engagement and Applied Skills

ERIC Educational Resources Information Center

Brown, James A. L.

2016-01-01

A pedagogic intervention, in the form of an inquiry-based peer-assisted learning project (as a practical student-led bioinformatics module), was assessed for its ability to increase students' engagement, practical bioinformatic skills and process-specific knowledge. Elements assessed were process-specific knowledge following module completion,…

Structural modulation of gut microbiota by chondroitin sulfate and its oligosaccharide.

PubMed

Shang, Qingsen; Shi, Jingjing; Song, Guanrui; Zhang, Meifang; Cai, Chao; Hao, Jiejie; Li, Guoyun; Yu, Guangli

2016-08-01

Chondroitin sulfate (CS) as a dietary supplement and a symptomatic slow acting (SYSA) drug has been used for years. Recently, CS has been demonstrated to be readily degraded and fermented in vitro by specific human gut microbes, hinting that dietary CS may pose a potential effect on gut microbiota composition in vivo. However, until now, little information is available on modulations of gut microbiota by CS. In the present study, modulations of gut microbiota in Kunming mice by CS and its oligosaccharide (CSO) were investigated by high-throughput sequencing. As evidenced by Heatmap and principal component analysis (PCA), the female microbiota were more vulnerable than the male microbiota to CS and CSO treatment. Besides, it is of interest to found that CS and CSO had differing effects on the abundance of Bacteroidales S24-7, Bacteroides, Helicobacter, Odoribacter, Prevotellaceae and Lactobacillus in male mice versus female mice. Collectively, we demonstrated a sex-dependent effect on gut microbiota of CS and CSO. In addition, since gut microbiota exerts a major effect on host physiology, our study highlighted that certain beneficial effects of CS may be associated with modulations of gut microbiota, which merits further investigation. Copyright © 2016 Elsevier B.V. All rights reserved.

The middleware architecture supports heterogeneous network systems for module-based personal robot system

NASA Astrophysics Data System (ADS)

Choo, Seongho; Li, Vitaly; Choi, Dong Hee; Jung, Gi Deck; Park, Hong Seong; Ryuh, Youngsun

2005-12-01

On developing the personal robot system presently, the internal architecture is every module those occupy separated functions are connected through heterogeneous network system. This module-based architecture supports specialization and division of labor at not only designing but also implementation, as an effect of this architecture, it can reduce developing times and costs for modules. Furthermore, because every module is connected among other modules through network systems, we can get easy integrations and synergy effect to apply advanced mutual functions by co-working some modules. In this architecture, one of the most important technologies is the network middleware that takes charge communications among each modules connected through heterogeneous networks systems. The network middleware acts as the human nerve system inside of personal robot system; it relays, transmits, and translates information appropriately between modules that are similar to human organizations. The network middleware supports various hardware platform, heterogeneous network systems (Ethernet, Wireless LAN, USB, IEEE 1394, CAN, CDMA-SMS, RS-232C). This paper discussed some mechanisms about our network middleware to intercommunication and routing among modules, methods for real-time data communication and fault-tolerant network service. There have designed and implemented a layered network middleware scheme, distributed routing management, network monitoring/notification technology on heterogeneous networks for these goals. The main theme is how to make routing information in our network middleware. Additionally, with this routing information table, we appended some features. Now we are designing, making a new version network middleware (we call 'OO M/W') that can support object-oriented operation, also are updating program sources itself for object-oriented architecture. It is lighter, faster, and can support more operation systems and heterogeneous network systems, but other general purposed middlewares like CORBA, UPnP, etc. can support only one network protocol or operating system.

Light intensity modulation in phototherapy

NASA Astrophysics Data System (ADS)

Lukyanovich, P. A.; Zon, B. A.; Kunin, A. A.; Pankova, S. N.

2015-04-01

A hypothesis that blocking ATP synthesis is one of the main causes of the stimulating effect is considered based on analysis of the primary photostimulation mechanisms. The light radiation intensity modulation is substantiated and the estimates of such modulation parameters are made. An explanation is offered to the stimulation efficiency decrease phenomenon at the increase of the radiation dose during the therapy. The results of clinical research of the medical treatment in preventive dentistry are presented depending on the spectrum and parameters of the light flux modulation.

Intelligent Load Manager (LOADMAN): Application of Expert System Technology to Load Management Problems in Power Generation and Distribution Systems

DTIC Science & Technology

1988-08-10

addrsesed to it, the wall-receptacle module energizes a relay. Modules can be built to use a triac instead and have the capacity to increase or decrease... modulated by other constraints for a safe, functional ana effective power distribution system. 2.2.3 BackuR Equipment Alternate power sources are...environments have limited sensor capability and no remote control capability. However, future enhancements to current equipment, such as frequency- modulated

Criteria for software modularization

NASA Technical Reports Server (NTRS)

Card, David N.; Page, Gerald T.; Mcgarry, Frank E.

1985-01-01

A central issue in programming practice involves determining the appropriate size and information content of a software module. This study attempted to determine the effectiveness of two widely used criteria for software modularization, strength and size, in reducing fault rate and development cost. Data from 453 FORTRAN modules developed by professional programmers were analyzed. The results indicated that module strength is a good criterion with respect to fault rate, whereas arbitrary module size limitations inhibit programmer productivity. This analysis is a first step toward defining empirically based standards for software modularization.

Demonstration of pulse controlled all-optical switch/modulator.

PubMed

Akin, Osman; Dinleyici, M S

2014-03-15

An all-optical pulse controlled switch/modulator based on evanescent coupling between a polymer slab waveguide and a single mode fiber is demonstrated. Very fast all-optical modulation/switching is achieved via Kerr effect of the nonlinear polymer placed in the evanescent region of the optical fiber. Local refractive index perturbation (Δn=-1.45612×10(-5)) on the thin film leads to 0.374 nW power modulation at the fiber output, which results in a switching efficiency of ≈1.5%.

The modulation of tumor vessel permeability by thalidomide and its impacts on different types of targeted drug delivery systems in a sarcoma mouse model.

PubMed

Wang, Dan; Fu, Jijun; Shi, Yujie; Peng, Dong; Yuan, Lan; He, Bing; Dai, Wenbing; Zhang, Hua; Wang, Xueqing; Tian, Jie; Zhang, Qiang

2016-09-28

The transport of nanocarriers is supposed to be based on EPR effect which is affected by diverse factors, so the modulation of EPR effect seems very significant for nanocarriers including targeted drug delivery systems (TDDSs). Besides, it is extremely unclear how the EPR effect impacts the fate of different types of TDDSs. To make the most advantage of EPR effect for TDDSs, it is definitely necessary to clarify these key issues. Here, we construct and characterize various TDDSs, including sterically-stabilized liposomes (SSL), RGD functionalized SSL (RGD-SSL) and novel 7PEP functionalized SSL (7PEP-SSL), loaded with doxorubicin (DOX), DIR or DID. Here, we modulate the permeability of tumor vessels by thalidomide (THD) in a sarcoma-bearing EPR mouse model via monitoring endogenous deoxygenated hemoglobin in circulation, and then we confirm the effect of THD on tumor vessel permeability by vessel density, vessel maturity, VEGF expression and so on. Importantly, we investigate and find the impacts of EPR effect on the antitumor efficacy, in vivo distribution and intratumoral microdistribution of the three TDDSs. Interestingly, the EPR effects affect different TDDSs differently. The elevated EPR effect enhances the tumor accumulation of SSL and RGD-SSL but fails to increase their efficacy. The RGD-SSL exhibits the best efficacy with the least fluctuation, demonstrating the advantage of angiogenesis targeted systems. 7PEP-SSL seems the biggest beneficiary of EPR effect, suggesting the significance of EPR modulation for cells targeted systems. Generally, this study demonstrates the feasibility of modulating EPR effect bidirectionally by THD as well as the impacts of EPR effect on different type of testing TDDSs based on this animal model. It certainly provides novel insight into the design and potential use of TDDSs. Copyright © 2016 Elsevier B.V. All rights reserved.

Impact of aerosols on ice crystal size

NASA Astrophysics Data System (ADS)

Zhao, Bin; Liou, Kuo-Nan; Gu, Yu; Jiang, Jonathan H.; Li, Qinbin; Fu, Rong; Huang, Lei; Liu, Xiaohong; Shi, Xiangjun; Su, Hui; He, Cenlin

2018-01-01

The interactions between aerosols and ice clouds represent one of the largest uncertainties in global radiative forcing from pre-industrial time to the present. In particular, the impact of aerosols on ice crystal effective radius (Rei), which is a key parameter determining ice clouds' net radiative effect, is highly uncertain due to limited and conflicting observational evidence. Here we investigate the effects of aerosols on Rei under different meteorological conditions using 9-year satellite observations. We find that the responses of Rei to aerosol loadings are modulated by water vapor amount in conjunction with several other meteorological parameters. While there is a significant negative correlation between Rei and aerosol loading in moist conditions, consistent with the "Twomey effect" for liquid clouds, a strong positive correlation between the two occurs in dry conditions. Simulations based on a cloud parcel model suggest that water vapor modulates the relative importance of different ice nucleation modes, leading to the opposite aerosol impacts between moist and dry conditions. When ice clouds are decomposed into those generated from deep convection and formed in situ, the water vapor modulation remains in effect for both ice cloud types, although the sensitivities of Rei to aerosols differ noticeably between them due to distinct formation mechanisms. The water vapor modulation can largely explain the difference in the responses of Rei to aerosol loadings in various seasons. A proper representation of the water vapor modulation is essential for an accurate estimate of aerosol-cloud radiative forcing produced by ice clouds.

Natural product derivative BIO promotes recovery after myocardial infarction via unique modulation of the cardiac microenvironment

PubMed Central

Kim, Yong Sook; Jeong, Hye-yun; Kim, Ah Ra; Kim, Woong-Hee; Cho, Haaglim; Um, JungIn; Seo, Youngha; Kang, Wan Seok; Jin, Suk-Won; Kim, Min Chul; Kim, Yong-Chul; Jung, Da-Woon; Williams, Darren R.; Ahn, Youngkeun

2016-01-01

The cardiac microenvironment includes cardiomyocytes, fibroblasts and macrophages, which regulate remodeling after myocardial infarction (MI). Targeting this microenvironment is a novel therapeutic approach for MI. We found that the natural compound derivative, BIO ((2′Z,3′E)-6-Bromoindirubin-3′-oxime) modulated the cardiac microenvironment to exert a therapeutic effect on MI. Using a series of co-culture studies, BIO induced proliferation in cardiomyocytes and inhibited proliferation in cardiac fibroblasts. BIO produced multiple anti-fibrotic effects in cardiac fibroblasts. In macrophages, BIO inhibited the expression of pro-inflammatory factors. Significantly, BIO modulated the molecular crosstalk between cardiac fibroblasts and differentiating macrophages to induce polarization to the anti-inflammatory M2 phenotype. In the optically transparent zebrafish-based heart failure model, BIO induced cardiomyocyte proliferation and completely recovered survival rate. BIO is a known glycogen synthase kinase-3β inhibitor, but these effects could not be recapitulated using the classical inhibitor, lithium chloride; indicating novel therapeutic effects of BIO. We identified the mechanism of BIO as differential modulation of p27 protein expression and potent induction of anti-inflammatory interleukin-10. In a rat MI model, BIO reduced fibrosis and improved cardiac performance. Histological analysis revealed modulation of the cardiac microenvironment by BIO, with increased presence of anti-inflammatory M2 macrophages. Our results demonstrate that BIO produces unique effects in the cardiac microenvironment to promote recovery post-MI. PMID:27510556

Effect of gravity modulation on thermosolutal convection in an infinite layer of fluid

NASA Astrophysics Data System (ADS)

Saunders, B. V.; Murray, B. T.; McFadden, G. B.; Coriell, S. R.; Wheeler, A. A.

1991-10-01

The effect of time-periodic vertical gravity modulation on the onset of thermosolutal convection in an infinite horizontal layer with stress free boundaries is studied using Floquet theory for the linear stability analysis. Situations are considered for which the fluid layer is stably stratified in either the fingering or diffusive regimes of double diffusive convection. Results are presented both with and without steady background acceleration. Modulation may stabilize an unstable base solution or destabilize a stable base solution. In addition to synchronous and subharmonic response to the modulation frequency, instability in the double diffusive system can occur via a complex conjugate mode. In the diffusive regime, where oscillatory onset occurs in the unmodulated system, regions of resonant instability occur and exhibit strong coupling with the unmodulated oscillatory frequency.

Implications of Green Tea and Its Constituents in the Prevention of Cancer via the Modulation of Cell Signalling Pathway

PubMed Central

Rahmani, Arshad H.; Al shabrmi, Fahad M.; Allemailem, Khaled S.; Aly, Salah M.; Khan, Masood A.

2015-01-01

Green tea is commonly used as a beverage worldwide, especially in China, Japan, Morocco, and Saudi Arabia. Green tea and its constituents have been considered very effective in the prevention and treatment of various diseases. It contains a variety of catechins, which show a pivotal role in the modulation of biological activities and also act as chemopreventive agents. Earlier studies have confirmed that green tea and its chief constituent epigallocatechin gallate (EGCG) have a potential role in the management of cancer through the modulation of cell signaling pathways. In this review, we focused on the beneficial effects of green tea and its constituents in the cancer prevention and treatment and its impact on modulation of molecular pathways. PMID:25977926

Discharge conditions for CW and pulse-modulated surface-wave plasmas in low-temperature sterilization

NASA Astrophysics Data System (ADS)

Xu, L.; Terashita, F.; Nonaka, H.; Ogino, A.; Nagata, T.; Koide, Y.; Nanko, S.; Kurawaki, I.; Nagatsu, M.

2006-01-01

The discharge conditions required for low-temperature plasma sterilization were investigated using low-pressure surface-wave plasma (SWP). The discharge conditions for both continuous wave (CW) and pulse-modulated SWPs in low-temperature sterilization of Geobacillus stearothermophilus with a population of 1.5 × 106 and 3.0 × 106 were studied by varying the microwave input power from 500 W to 3 kW, and the effective plasma treatment time from 40 to 300 s. Results showed that sterilization was possible in a shorter treatment time using a higher microwave power for both CW and pulse-modulated SWPs. Pulse-modulated SWPs gave effective sterilization at a temperature roughly 10 to 20 °C below that of CW SWPs under the same average microwave power.

Incorporating partial shining effects in proton pencil-beam dose calculation

NASA Astrophysics Data System (ADS)

Li, Yupeng; Zhang, Xiaodong; Fwu Lii, Ming; Sahoo, Narayan; Zhu, Ron X.; Gillin, Michael; Mohan, Radhe

2008-02-01

A range modulator wheel (RMW) is an essential component in passively scattered proton therapy. We have observed that a proton beam spot may shine on multiple steps of the RMW. Proton dose calculation algorithms normally do not consider the partial shining effect, and thus overestimate the dose at the proximal shoulder of spread-out Bragg peak (SOBP) compared with the measurement. If the SOBP is adjusted to better fit the plateau region, the entrance dose is likely to be underestimated. In this work, we developed an algorithm that can be used to model this effect and to allow for dose calculations that better fit the measured SOBP. First, a set of apparent modulator weights was calculated without considering partial shining. Next, protons spilled from the accelerator reaching the modulator wheel were simplified as a circular spot of uniform intensity. A weight-splitting process was then performed to generate a set of effective modulator weights with the partial shining effect incorporated. The SOBPs of eight options, which are used to label different combinations of proton-beam energy and scattering devices, were calculated with the generated effective weights. Our algorithm fitted the measured SOBP at the proximal and entrance regions much better than the ones without considering partial shining effect for all SOBPs of the eight options. In a prostate patient, we found that dose calculation without considering partial shining effect underestimated the femoral head and skin dose.

Power-Stepped HF Cross Modulation Experiments at HAARP

NASA Astrophysics Data System (ADS)

Greene, S.; Moore, R. C.; Langston, J. S.

2013-12-01

High frequency (HF) cross modulation experiments are a well established means for probing the HF-modified characteristics of the D-region ionosphere. In this paper, we apply experimental observations of HF cross-modulation to the related problem of ELF/VLF wave generation. HF cross-modulation measurements are used to evaluate the efficiency of ionospheric conductivity modulation during power-stepped modulated HF heating experiments. The results are compared to previously published dependencies of ELF/VLF wave amplitude on HF peak power. The experiments were performed during the March 2013 campaign at the High Frequency Active Auroral Research Program (HAARP) Observatory. HAARP was operated in a dual-beam transmission format: the first beam heated the ionosphere using sinusoidal amplitude modulation while the second beam broadcast a series of low-power probe pulses. The peak power of the modulating beam was incremented in 1-dB steps. We compare the minimum and maximum cross-modulation effect and the amplitude of the resulting cross-modulation waveform to the expected power-law dependence of ELF/VLF wave amplitude on HF power.

On the benefit of DMT modulation in nonlinear VLC systems.

PubMed

Qian, Hua; Cai, Sunzeng; Yao, Saijie; Zhou, Ting; Yang, Yang; Wang, Xudong

2015-02-09

In a visible light communication (VLC) system, the nonlinear characteristic of the light emitting diode (LED) in transmitter is a limiting factor of system performance. Modern modulation signals with large peak-to-power-ratio (PAPR) suffers uneven distortion. The nonlinear response directly impacts the intensity modulation and direct detection VLC system with pulse-amplitude modulation (PAM). The amplitude of the PAM signal is distorted unevenly and large signal is vulnerable to noise. Orthogonal linear transformations, such as discrete multi-tone (DMT) modulation, can spread the nonlinear effects evenly to each data symbol, thus perform better than PAM signals. In this paper, we provide theoretical analysis on the benefit of DMT modulation in nonlinear VLC system. We show that the DMT modulation is a better choice than the PAM modulation for the VLC system as the DMT modulation is more robust against nonlinearity. We also show that the post-distortion nonlinear elimination method, which is applied at the receiver, can be a reliable solution to the nonlinear VLC system. Simulation results show that the post-distortion greatly improves the system performance for the DMT modulation.

Investigation of television transmission using adaptive delta modulation principles

NASA Technical Reports Server (NTRS)

Schilling, D. L.

1976-01-01

The results are presented of a study on the use of the delta modulator as a digital encoder of television signals. The computer simulation of different delta modulators was studied in order to find a satisfactory delta modulator. After finding a suitable delta modulator algorithm via computer simulation, the results were analyzed and then implemented in hardware to study its ability to encode real time motion pictures from an NTSC format television camera. The effects of channel errors on the delta modulated video signal were tested along with several error correction algorithms via computer simulation. A very high speed delta modulator was built (out of ECL logic), incorporating the most promising of the correction schemes, so that it could be tested on real time motion pictures. Delta modulators were investigated which could achieve significant bandwidth reduction without regard to complexity or speed. The first scheme investigated was a real time frame to frame encoding scheme which required the assembly of fourteen, 131,000 bit long shift registers as well as a high speed delta modulator. The other schemes involved the computer simulation of two dimensional delta modulator algorithms.

Detecting the role of individual species for overyielding in experimental grassland communities composed of potentially dominant species.

PubMed

Roscher, Christiane; Schumacher, Jens; Weisser, Wolfgang W; Schmid, Bernhard; Schulze, Ernst-Detlef

2007-12-01

Several studies have shown that the contribution of individual species to the positive relationship between species richness and community biomass production cannot be easily predicted from species monocultures. Here, we used a biodiversity experiment with a pool of nine potentially dominant grassland species to relate the species richness-productivity relationship to responses in density, size and aboveground allocation patterns of individual species. Aboveground community biomass increased strongly with the transition from monocultures to two-species mixtures but only slightly with the transition from two- to nine-species mixtures. Tripartite partitioning showed that the strong increase shown by the former was due to trait-independent complementarity effects, while the slight increase shown by the latter was due to dominance effects. Trait-dependent complementarity effects depended on species composition. Relative yield total (RYT) was greater than 1 (RYT>1) in mixtures but did not increase with species richness, which is consistent with the constant complementarity effect. The relative yield (RY) of only one species, Arrhenatherum elatius, continually increased with species richness, while those of the other species studied decreased with species richness or varied among different species compositions within richness levels. High observed/expected RYs (RYo/RYe>1) of individual species were mainly due to increased module densities, whereas low observed/expected RYs (RYo/RYe<1) were due to more pronounced decreases in module density (species with stoloniferous or creeping growth) or module size (species with clearly-defined plant individuals). The trade-off between module density and size, typical for plant populations under the law of constant final yield, was compensated among species. The positive trait-independent complementarity effect could be explained by an increase in community module density, which reached a maximum at low species richness. In contrast, the increasing dominance effect was attributable to the species-specific ability, in particular that of A. elatius, to increase module size, while intrinsic growth limitations led to a suppression of the remaining species in many mixtures.

Using experimental design modules for process characterization in manufacturing/materials processes laboratories

NASA Technical Reports Server (NTRS)

Ankenman, Bruce; Ermer, Donald; Clum, James A.

1994-01-01

Modules dealing with statistical experimental design (SED), process modeling and improvement, and response surface methods have been developed and tested in two laboratory courses. One course was a manufacturing processes course in Mechanical Engineering and the other course was a materials processing course in Materials Science and Engineering. Each module is used as an 'experiment' in the course with the intent that subsequent course experiments will use SED methods for analysis and interpretation of data. Evaluation of the modules' effectiveness has been done by both survey questionnaires and inclusion of the module methodology in course examination questions. Results of the evaluation have been very positive. Those evaluation results and details of the modules' content and implementation are presented. The modules represent an important component for updating laboratory instruction and to provide training in quality for improved engineering practice.

Electro-optic modulator with ultra-low residual amplitude modulation for frequency modulation and laser stabilization.

PubMed

Tai, Zhaoyang; Yan, Lulu; Zhang, Yanyan; Zhang, Xiaofei; Guo, Wenge; Zhang, Shougang; Jiang, Haifeng

2016-12-01

The reduction of the residual amplitude modulation (RAM) induced by electro-optic modulation is essential for many applications of frequency modulation spectroscopy requiring a lower system noise floor. Here, we demonstrate a simple passive approach employing an electro-optic modulator (EOM) cut at Brewster's angle. The proposed EOM exhibits a RAM of a few parts per million, which is comparable with that achieved by a common EOM under critical active temperature and bias voltage controls. The frequency instability of a 10 cm cavity-stabilized laser induced by the RAM effect of the proposed EOM is below 3×10^-17 for integration times from 1 to 1000 s, and below 4×10^-16 for comprehensive noise contributions for integration times from 1 to 100 s.

Acceleration Recorder and Playback Module

NASA Technical Reports Server (NTRS)

Bozeman, Richard J., Jr. (Inventor)

1996-01-01

The present invention is directed to methods and apparatus relating to an accelerometer electrical signal recorder and playback module. The recorder module may be manufactured in lightweight configuration and includes analog memory components to store data. Signal conditioning circuitry is incorporated into the module so that signals may be connected directly from the accelerometer to the recorder module. A battery pack may be included for powering both the module and the accelerometer. Timing circuitry is included to control the time duration within which data is recorded or played back so as to avoid overloading the analog memory components. Multiple accelerometer signal recordings may be taken simultaneously without analog to digital circuits, multiplexing circuitry or software to compensate for the effects of multiplexing the signals.

Acceleration recorder and playback module

NASA Astrophysics Data System (ADS)

Bozeman, Richard J., Jr.

1994-11-01

The present invention is directed to methods and apparatus relating to an accelerometer electrical signal recorder and playback module. The recorder module may be manufactured in lightweight configuration and includes analog memory components to store data. Signal conditioning circuitry is incorporated into the module so that signals may be connected directly from the accelerometer to the recorder module. A battery pack may be included for powering both the module and the accelerometer. Timing circuitry is included to control the time duration within which data is recorded or played back so as to avoid overloading the analog memory components. Multiple accelerometer signal recordings may be taken simultaneously without analog to digital circuits, multiplexing circuitry or software to compensate for the effects of multiplexing the signals.

Acceleration recorder and playback module

NASA Astrophysics Data System (ADS)

Bozeman, Richard J., Jr.

1992-09-01

The present invention is directed to methods and apparatus relating to an accelerometer electrical signal recorder and playback module. The recorder module may be manufactured in lightweight configuration and includes analog memory components to store data. Signal conditioning circuitry is incorporated into the module so that signals may be connected directly from the accelerometer to the recorder module. A battery pack may be included for powering both the module and the accelerometer. Timing circuitry is included to control the time duration within which data is recorded or played back so as to avoid overloading the analog memory components. Multiple accelerometer signal recordings may be taken simultaneously without analog to digital circuits, multiplexing circuitry or software to compensate for the effects of multiplexing the signals.

Acceleration recorder and playback module

NASA Technical Reports Server (NTRS)

Bozeman, Richard J., Jr. (Inventor)

1994-01-01

The present invention is directed to methods and apparatus relating to an accelerometer electrical signal recorder and playback module. The recorder module may be manufactured in lightweight configuration and includes analog memory components to store data. Signal conditioning circuitry is incorporated into the module so that signals may be connected directly from the accelerometer to the recorder module. A battery pack may be included for powering both the module and the accelerometer. Timing circuitry is included to control the time duration within which data is recorded or played back so as to avoid overloading the analog memory components. Multiple accelerometer signal recordings may be taken simultaneously without analog to digital circuits, multiplexing circuitry or software to compensate for the effects of multiplexing the signals.

Thermal and Electrical Effects of Partial Shade in Monolithic Thin-Film Photovoltaic Modules: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silverman, Timothy J.; Deceglie, Michael G.; Sun, Xingshu

2015-09-02

Photovoltaic cells can be damaged by reverse bias stress, which arises during service when a monolithically integrated thin-film module is partially shaded. We introduce a model for describing a module's internal thermal and electrical state, which cannot normally be measured. Using this model and experimental measurements, we present several results with relevance for reliability testing and module engineering: Modules with a small breakdown voltage experience less stress than those with a large breakdown voltage, with some exceptions for modules having light-enhanced reverse breakdown. Masks leaving a small part of the masked cells illuminated can lead to very high temperature andmore » current density compared to masks covering entire cells.« less

Thermal and Electrical Effects of Partial Shade in Monolithic Thin-Film Photovoltaic Modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silverman, Timothy J.; Deceglie, Michael G.; Sun, Xingshu

2015-06-14

Photovoltaic cells can be damaged by reverse bias stress, which arises during service when a monolithically integrated thin-film module is partially shaded. We introduce a model for describing a module's internal thermal and electrical state, which cannot normally be measured. Using this model and experimental measurements, we present several results with relevance for reliability testing and module engineering: Modules with a small breakdown voltage experience less stress than those with a large breakdown voltage, with some exceptions for modules having light-enhanced reverse breakdown. Masks leaving a small part of the masked cells illuminated can lead to very high temperature andmore » current density compared to masks covering entire cells.« less

High-frequency modulation of the four states of polarization of light with a single phase modulator

NASA Astrophysics Data System (ADS)

Compain, Eric; Drevillon, Bernard

1998-04-01

A method for light polarization modulation is described. It allows us to independently modulate, at a high frequency, the four components of the Stokes vector of light using a single phase modulator. It works in a double-pass configuration: the polarization of light is modulated a first time by the phase modulator, and is then modified by a coupling object before being modulated a second time by the same modulator. The coupling object consists of multiple glass plates, oriented at the Brewster angle, acting as a partial polarizer and in a right angle prism acting as a phase shifter and back reflector. Its polarimetric properties are obtained from refractive index contrast effects, which provides optimized and constant properties over a wide spectral range. The phase modulator can be either an electro-optic modulator providing a very high-frequency capability (up to 100 MHz) or a photoelastic modulator providing a wide spectral range capability. It is robust because there is no moving part and simple to implement because of the presence of one modulation. It displays a high level of sensitivity because all the components are high-frequency modulated. Two applications using this modulator in a polarimeter or in a polarization states generator are described. The four modulations, having the same fundamental frequency, are easily demodulated by numerical data processing. Optimized demodulation processing, adapted to the different kind of phase modulator is described. Its adaptation taking into account the bandwidth limitation and the variation of the sampling phase, are finally presented in the case of a photoelastic modulator.

Additive Effects of Threat-of-Shock and Picture Valence on Startle Reflex Modulation

PubMed Central

Bublatzky, Florian; Guerra, Pedro M.; Pastor, M. Carmen; Schupp, Harald T.; Vila, Jaime

2013-01-01

The present study examined the effects of sustained anticipatory anxiety on the affective modulation of the eyeblink startle reflex. Towards this end, pleasant, neutral and unpleasant pictures were presented as a continuous stream during alternating threat-of-shock and safety periods, which were cued by colored picture frames. Orbicularis-EMG to auditory startle probes and electrodermal activity were recorded. Previous findings regarding affective picture valence and threat-of-shock modulation were replicated. Of main interest, anticipating aversive events and viewing affective pictures additively modulated defensive activation. Specifically, despite overall potentiated startle blink magnitude in threat-of-shock conditions, the startle reflex remained sensitive to hedonic picture valence. Finally, skin conductance level revealed sustained sympathetic activation throughout the entire experiment during threat- compared to safety-periods. Overall, defensive activation by physical threat appears to operate independently from reflex modulation by picture media. The present data confirms the importance of simultaneously manipulating phasic-fear and sustained-anxiety in studying both normal and abnormal anxiety. PMID:23342060

Virtual patient training to improve reproductive health care for women with intellectual disabilities.

PubMed

Boyd, Sara E; Sanders, Carla L; Kleinert, Harold L; Huff, Marlene B; Lock, Sharon; Johnson, Stephanie; Clevenger, Kim; Bush, Nathania A; Van Dyke, Eileen; Clark, Tara L

2008-01-01

A multimedia virtual patient module, involving the case of a young woman with mild intellectual disabilities with a complaint of diffuse abdominal pain, was developed as a clinical training tool for students in health care professions. Primary objectives following use of the module included improved knowledge and reduced perception of difficulty in treating women's health patients with intellectual disabilities. The module was developed using an iterative, collaborative process of a core development team that included medical professionals, multimedia specialists, the parent of a child with intellectual disability, and a disability advocate. Over the course of the module, students were required to identify appropriate and effective clinician-patient interactions in addition to relevant medical and developmental concerns for this patient population. Pilot data from a sample of nursing, physician assistant, and medical students suggest that the module is an effective tool for both improving students' knowledge and reducing their perception of difficulty in providing care to women's health patients with intellectual disabilities.

The effect of gravity modulation on thermosolutal convection in an infinite layer of fluid

NASA Astrophysics Data System (ADS)

Saunders, B. V.; Murray, B. T.; McFadden, G. B.; Coriell, S. R.; Wheeler, A. A.

1992-06-01

The effect of time-periodic vertical gravity modulation on the onset of thermosolutal convection in an infinite horizontal layer with stress-free boundaries is investigated using Floquet theory for the linear stability analysis. Situations for which the fluid layer is stably stratified in either the fingering or diffusive regimes of double-diffusive convection are considered. Results are presented both with and without steady background acceleration. Modulation may stabilize an unstable base solution or destabilize a stable base solution. In addition to synchronous and subharmonic response to the modulation frequency, instability in the double diffusive system can occur via a complex conjugate mode. In the diffusive regime, where oscillatory onset occurs in the unmodulated system, regions of resonant instability occur and exhibit strong coupling with the unmodulated oscillatory frequency. The response to modulation of the fundamental instability of the unmodulated system is described both analytically and numerically; in the double-diffusive system this mode persists under subcritical conditions as a high-frequency lobe.

The effect of gravity modulation on thermosolutal convection in an infinite layer of fluid

NASA Technical Reports Server (NTRS)

Saunders, B. V.; Murray, B. T.; Mcfadden, G. B.; Coriell, S. R.; Wheeler, A. A.

1992-01-01

The effect of time-periodic vertical gravity modulation on the onset of thermosolutal convection in an infinite horizontal layer with stress-free boundaries is investigated using Floquet theory for the linear stability analysis. Situations for which the fluid layer is stably stratified in either the fingering or diffusive regimes of double-diffusive convection are considered. Results are presented both with and without steady background acceleration. Modulation may stabilize an unstable base solution or destabilize a stable base solution. In addition to synchronous and subharmonic response to the modulation frequency, instability in the double diffusive system can occur via a complex conjugate mode. In the diffusive regime, where oscillatory onset occurs in the unmodulated system, regions of resonant instability occur and exhibit strong coupling with the unmodulated oscillatory frequency. The response to modulation of the fundamental instability of the unmodulated system is described both analytically and numerically; in the double-diffusive system this mode persists under subcritical conditions as a high-frequency lobe.

Environmental testing of terrestrial flat plate photovoltaic modules

NASA Technical Reports Server (NTRS)

Hoffman, A.; Griffith, J.

1979-01-01

The Low-Cost Solar Array (LSA) Project at the Jet Propulsion Laboratory has as one objective: the development and implementation of environmental tests for flat plate photovoltaic modules as part of the Department of Energy's terrestrial photovoltaic program. Modules procured under this program have been subjected to a variety of laboratory tests intended to simulate service environments, and the results of these tests have been compared to available data from actual field service. This comparison indicates that certain tests (notably temperature cycling, humidity cycling, and cyclic pressure loading) are effective indicators of some forms of field failures. Other tests have yielded results useful in formulating module design guidelines. Not all effects noted in field service have been successfully reproduced in the laboratory, however, and work is continuing in order to improve the value of the test program as a tool for evaluating module design and workmanship. This paper contains a review of these ongoing efforts and an assessment of significant test results to date.

Face age modulates gaze following in young adults.

PubMed

Ciardo, Francesca; Marino, Barbara F M; Actis-Grosso, Rossana; Rossetti, Angela; Ricciardelli, Paola

2014-04-22

Gaze-following behaviour is considered crucial for social interactions which are influenced by social similarity. We investigated whether the degree of similarity, as indicated by the perceived age of another person, can modulate gaze following. Participants of three different age-groups (18-25; 35-45; over 65) performed an eye movement (a saccade) towards an instructed target while ignoring the gaze-shift of distracters of different age-ranges (6-10; 18-25; 35-45; over 70). The results show that gaze following was modulated by the distracter face age only for young adults. Particularly, the over 70 year-old distracters exerted the least interference effect. The distracters of a similar age-range as the young adults (18-25; 35-45) had the most effect, indicating a blurred own-age bias (OAB) only for the young age group. These findings suggest that face age can modulate gaze following, but this modulation could be due to factors other than just OAB (e.g., familiarity).

Spin polarization of {sup 87}Rb atoms with ultranarrow linewidth diode laser: Numerical simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Z. G.; Interdisciplinary Center of Quantum Information, National University of Defense Technology, Changsha, 410073; College of Science, National University of Defense Technology, Changsha, 410073

2016-08-15

In order to polarize {sup 87}Rb vapor effectively with ultranarrow linewidth diode laser, we studied the polarization as a function of some parameters including buffer gas pressure and laser power. Moreover, we also discussed the methods which split or modulate the diode laser frequency so as to pump the two ground hyperfine levels efficiently. We obtained some useful results through numerical simulation. If the buffer gas pressure is so high that the hyperfine structure is unresolved, the polarization is insensitive to laser frequency at peak absorption point so frequency splitting and frequency modulation methods do not show improvement. At lowmore » pressure and laser power large enough, where the hyperfine structure is clearly resolved, frequency splitting and frequency modulation methods can increase polarization effectively. For laser diodes, frequency modulation is easily realized with current modulation, so this method is attractive since it does not add any other components in the pumping laser system.« less

Effects of auditory selective attention on chirp evoked auditory steady state responses.

PubMed

Bohr, Andreas; Bernarding, Corinna; Strauss, Daniel J; Corona-Strauss, Farah I

2011-01-01

Auditory steady state responses (ASSRs) are frequently used to assess auditory function. Recently, the interest in effects of attention on ASSRs has increased. In this paper, we investigated for the first time possible effects of attention on AS-SRs evoked by amplitude modulated and frequency modulated chirps paradigms. Different paradigms were designed using chirps with low and high frequency content, and the stimulation was presented in a monaural and dichotic modality. A total of 10 young subjects participated in the study, they were instructed to ignore the stimuli and after a second repetition they had to detect a deviant stimulus. In the time domain analysis, we found enhanced amplitudes for the attended conditions. Furthermore, we noticed higher amplitudes values for the condition using frequency modulated low frequency chirps evoked by a monaural stimulation. The most difference between attended and unattended modality was exhibited at the dichotic case of the amplitude modulated condition using chirps with low frequency content.

Phonological experience modulates voice discrimination: Evidence from functional brain networks analysis.

PubMed

Hu, Xueping; Wang, Xiangpeng; Gu, Yan; Luo, Pei; Yin, Shouhang; Wang, Lijun; Fu, Chao; Qiao, Lei; Du, Yi; Chen, Antao

2017-10-01

Numerous behavioral studies have found a modulation effect of phonological experience on voice discrimination. However, the neural substrates underpinning this phenomenon are poorly understood. Here we manipulated language familiarity to test the hypothesis that phonological experience affects voice discrimination via mediating the engagement of multiple perceptual and cognitive resources. The results showed that during voice discrimination, the activation of several prefrontal regions was modulated by language familiarity. More importantly, the same effect was observed concerning the functional connectivity from the fronto-parietal network to the voice-identity network (VIN), and from the default mode network to the VIN. Our findings indicate that phonological experience could bias the recruitment of cognitive control and information retrieval/comparison processes during voice discrimination. Therefore, the study unravels the neural substrates subserving the modulation effect of phonological experience on voice discrimination, and provides new insights into studying voice discrimination from the perspective of network interactions. Copyright © 2017. Published by Elsevier Inc.

Memory Effects of Benzodiazepines: Memory Stages and Types Versus Binding-Site Subtypes

PubMed Central

Savić, Miroslav M.; Obradović, Dragan I.; Ugrešić, Nenad D.; Bokonjić, Dubravko R.

2005-01-01

Benzodiazepines are well established as inhibitory modulators of memory processing. This effect is especially prominent when applied before the acquisition phase of a memory task. This minireview concentrates on the putative subtype selectivity of the acquisition-impairing action of benzodiazepines. Namely, recent genetic studies and standard behavioral tests employing subtype-selective ligands pointed to the predominant involvement of two subtypes of benzodiazepine binding sites in memory modulation. Explicit memory learning seems to be affected through the GABAA receptors containing the α1 and α1 subunits, whereas the effects on procedural memory can be mainly mediated by the α1 subunit. The pervading involvement of the α1 subunit in memory modulation is not at all unexpected because this subunit is the major subtype, present in 60% of all GABAA receptors. On the other hand, the role of α5 subunits, mainly expressed in the hippocampus, in modulating distinct forms of memory gives promise of selective pharmacological coping with certain memory deficit states. PMID:16444900

Reward modulates perception in binocular rivalry.

PubMed

Marx, Svenja; Einhäuser, Wolfgang

2015-01-14

Our perception does not provide us with an exact imprint of the outside world, but is continuously adapted to our internal expectations, task sets, and behavioral goals. Although effects of reward-or value in general-on perception therefore seem likely, how valuation modulates perception and how such modulation relates to attention is largely unknown. We probed effects of reward on perception by using a binocular-rivalry paradigm. Distinct gratings drifting in opposite directions were presented to each observer's eyes. To objectify their subjective perceptual experience, the optokinetic nystagmus was used as measure of current perceptual dominance. In a first experiment, one of the percepts was either rewarded or attended. We found that reward and attention similarly biased perception. In a second experiment, observers performed an attentionally demanding task either on the rewarded stimulus, the other stimulus, or both. We found that-on top of an attentional effect on perception-at each level of attentional load, reward still modulated perception by increasing the dominance of the rewarded percept. Similarly, penalizing one percept increased dominance of the other at each level of attentional load. In turn, rewarding-and similarly nonpunishing-a percept yielded performance benefits that are typically associated with selective attention. In conclusion, our data show that value modulates perception in a similar way as the volitional deployment of attention, even though the relative effect of value is largely unaffected by an attention task. © 2015 ARVO.

Trial type probability modulates the cost of antisaccades

PubMed Central

Chiau, Hui-Yan; Tseng, Philip; Su, Jia-Han; Tzeng, Ovid J. L.; Hung, Daisy L.; Muggleton, Neil G.

2011-01-01

The antisaccade task, where eye movements are made away from a target, has been used to investigate the flexibility of cognitive control of behavior. Antisaccades usually have longer saccade latencies than prosaccades, the so-called antisaccade cost. Recent studies have shown that this antisaccade cost can be modulated by event probability. This may mean that the antisaccade cost can be reduced, or even reversed, if the probability of surrounding events favors the execution of antisaccades. The probabilities of prosaccades and antisaccades were systematically manipulated by changing the proportion of a certain type of trial in an interleaved pro/antisaccades task. We aimed to disentangle the intertwined relationship between trial type probabilities and the antisaccade cost with the ultimate goal of elucidating how probabilities of trial types modulate human flexible behaviors, as well as the characteristics of such modulation effects. To this end, we examined whether implicit trial type probability can influence saccade latencies and also manipulated the difficulty of cue discriminability to see how effects of trial type probability would change when the demand on visual perceptual analysis was high or low. A mixed-effects model was applied to the analysis to dissect the factors contributing to the modulation effects of trial type probabilities. Our results suggest that the trial type probability is one robust determinant of antisaccade cost. These findings highlight the importance of implicit probability in the flexibility of cognitive control of behavior. PMID:21543748

Acceptance and Commitment Therapy modules: Differential impact on treatment processes and outcomes.

PubMed

Villatte, Jennifer L; Vilardaga, Roger; Villatte, Matthieu; Plumb Vilardaga, Jennifer C; Atkins, David C; Hayes, Steven C

2016-02-01

A modular, transdiagnostic approach to treatment design and implementation may increase the public health impact of evidence-based psychosocial interventions. Such an approach relies on algorithms for selecting and implementing treatment components intended to have a specific therapeutic effect, yet there is little evidence for how components function independent of their treatment packages when employed in clinical service settings. This study aimed to demonstrate the specificity of treatment effects for two components of Acceptance and Commitment Therapy (ACT), a promising candidate for modularization. A randomized, nonconcurrent, multiple-baseline across participants design was used to examine component effects on treatment processes and outcomes in 15 adults seeking mental health treatment. The ACT OPEN module targeted acceptance and cognitive defusion; the ACT ENGAGED module targeted values-based activation and persistence. According to Tau-U analyses, both modules produced significant improvements in psychiatric symptoms, quality of life, and targeted therapeutic processes. ACT ENGAGED demonstrated greater improvements in quality of life and values-based activation. ACT OPEN showed greater improvements in symptom severity, acceptance, and defusion. Both modules improved awareness and non-reactivity, which were mutually targeted, though using distinct intervention procedures. Both interventions demonstrated high treatment acceptability, completion, and patient satisfaction. Treatment effects were maintained at 3-month follow up. ACT components should be considered for inclusion in a modular approach to implementing evidence-based psychosocial interventions for adults. Copyright © 2015 Elsevier Ltd. All rights reserved.

Are online learning modules an effective way to deliver hand trauma management continuing medical education to emergency physicians?

PubMed

Williams, Jason G

2014-01-01

The enormity of modern medical knowledge and the rapidity of change have created increased need for ongoing or continuing medical education (CME) for physicians. Online CME is attractive for its availability at any time and any place, low cost and potentially increased effectiveness compared with traditional face-to-face delivery. To determine whether online CME modules are an effective method for delivering plastic surgery CME to primary care physicians. A needs assessment survey was conducted among all emergency and family physicians in Nova Scotia. Results indicated that this type of program was appealing, and that hand trauma related topics were most desired for CME. 7 Lesson Builder (SoftChalk LLC, www.softchalk.com) was used to construct a multimedia e-learning module that was distributed along with a pretest, post-test and feedback questionnaire. Quantitative (pre- and post-test scores) and qualitative (feedback responses) data were analyzed. The 32 participants who completed the study indicated that it was a positive and enjoyable experience, and that there was a need for more resources like this. Compared with pretest scores, there was a significant gain in knowledge following completion of the module (P=0.001). The present study demonstrated that an e-learning format is attractive for this population and effective in increasing knowledge. This positive outcome will lead to development of additional modules.

Excavation of attractor modules for nasopharyngeal carcinoma via integrating systemic module inference with attract method.

PubMed

Jiang, T; Jiang, C-Y; Shu, J-H; Xu, Y-J

2017-07-10

The molecular mechanism of nasopharyngeal carcinoma (NPC) is poorly understood and effective therapeutic approaches are needed. This research aimed to excavate the attractor modules involved in the progression of NPC and provide further understanding of the underlying mechanism of NPC. Based on the gene expression data of NPC, two specific protein-protein interaction networks for NPC and control conditions were re-weighted using Pearson correlation coefficient. Then, a systematic tracking of candidate modules was conducted on the re-weighted networks via cliques algorithm, and a total of 19 and 38 modules were separately identified from NPC and control networks, respectively. Among them, 8 pairs of modules with similar gene composition were selected, and 2 attractor modules were identified via the attract method. Functional analysis indicated that these two attractor modules participate in one common bioprocess of cell division. Based on the strategy of integrating systemic module inference with the attract method, we successfully identified 2 attractor modules. These attractor modules might play important roles in the molecular pathogenesis of NPC via affecting the bioprocess of cell division in a conjunct way. Further research is needed to explore the correlations between cell division and NPC.

Hermetic edge sealing of photovoltaic modules

NASA Astrophysics Data System (ADS)

1983-02-01

The edge sealing technique is accomplished by a combination of a chemical bond between glass and aluminum, formed by electrostatic bonding, and a metallurgical bond between aluminum and aluminum, formed by ultrasonic welding. Such a glass to metal seal promises to provide a low cost, long lifetime, highly effective hermetic seal which can protect module components from severe environments. Development of the sealing techniques and demonstration of their effectiveness by fabricating a small number of dummy modules, up to eight inches square in size, and testing them for hermeticity using helium leak testing methods are reviewed. Non-destructive test methods are investigated.

Modulation of Nrf2 by Olive Oil and Wine Polyphenols and Neuroprotection

PubMed Central

Martínez-Huélamo, Miriam; Boronat, Anna; de la Torre, Rafael

2017-01-01

Strong adherence to a Mediterranean diet is associated with improved cognitive function and a lower prevalence of mild cognitive impairment. Olive oil and red wine are rich sources of polyphenols which are responsible in part for the beneficial effects on cognitive functioning. Polyphenols induce endogenous antioxidant defense mechanisms by modulating transcription factors such as the nuclear factor (erythroid-derived 2)-like 2 (Nrf2). This review discusses the scientific data supporting the modulating effect of olive oil and red wine polyphenols on Nrf2 expression, and the potential health benefits associated with cognitive functioning. PMID:28954417

Spatial resolution limitation of liquid crystal spatial light modulator

NASA Astrophysics Data System (ADS)

Wang, Xinghua; Wang, Bin; McManamon, Paul F., III; Pouch, John J.; Miranda, Felix A.; Anderson, James E.; Bos, Philip J.

2004-10-01

The effect of fringing electric fields in a liquid crystal (LC) Optical Phased Array (OPA), also referred to as a spatial light modulator (SLM), is a governing factor that determines the diffraction efficiency (DE) of the LC OPA for high resolution spatial phase modulation. In this article, the fringing field effect in a high resolution LC OPA is studied by accurate modeling the DE of the LC blazed gratings by LC director simulation and Finite Difference Time Domain (FDTD) simulation. Influence factors that contribute significantly to the DE are discussed. Such results provide fundamental understanding for high resolution LC devices.

Hermetic edge sealing of photovoltaic modules

NASA Technical Reports Server (NTRS)

1983-01-01

The edge sealing technique is accomplished by a combination of a chemical bond between glass and aluminum, formed by electrostatic bonding, and a metallurgical bond between aluminum and aluminum, formed by ultrasonic welding. Such a glass to metal seal promises to provide a low cost, long lifetime, highly effective hermetic seal which can protect module components from severe environments. Development of the sealing techniques and demonstration of their effectiveness by fabricating a small number of dummy modules, up to eight inches square in size, and testing them for hermeticity using helium leak testing methods are reviewed. Non-destructive test methods are investigated.

A hybrid modulation for the dissemination of weather data to aircraft

NASA Technical Reports Server (NTRS)

Akos, Dennis M.

1991-01-01

Ohio University is continuing to conduct research to improve its system for weather data dissemination to aircraft. The current experimental system transmit compressed weather radar reflectivity patterns from a ground based station to aircraft. Although an effective system, the limited frequency spectrum does not provide a channel for transmission. This introduces the idea of a hybrid modulation. The hybrid technique encodes weather data using phase modulation (PM) onto an existing aeronautical channel which employs amplitude modulation (AM) for voice signal transmission. Ideally, the two modulations are independent of one another. The planned implementation and basis of the system are the reviewed.

Sprayed shielding of plastic-encapsulated electronic modules

NASA Technical Reports Server (NTRS)

Muller, A. N.

1969-01-01

Metallic coating directly sprayed on electronic modules provides simple and reliable lightweight protection against radio frequency interference. A plasma arc may be used. Aluminum and copper are the most effective metals.

Effect of vegetation type on treatment performance and bioelectric production of constructed wetland modules combined with microbial fuel cell (CW-MFC) treating synthetic wastewater.

PubMed

Saz, Çağdaş; Türe, Cengiz; Türker, Onur Can; Yakar, Anıl

2018-03-01

An operation of microcosm-constructed wetland modules combined with microbial fuel cell device (CW-MFC) was assessed for wastewater treatment and bioelectric generation. One of the crucial aims of the present experiment is also to determine effect of vegetation on wastewater treatment process and bioelectric production in wetland matrix with microbial fuel cell. Accordingly, CW-MFC modules with vegetation had higher treatment efficiency compared to unplanted wetland module, and average COD, NH 4 + , and TP removal efficiency in vegetated wetland modules were ranged from 85 to 88%, 95 to 97%, and 95 to 97%, respectively. However, the highest NO 3 - removal (63%) was achieved by unplanted control module during the experiment period. The maximum average output voltage, power density, and Coulombic efficiency were obtained in wetland module vegetated with Typha angustifolia for 1.01 ± 0.14 V, 7.47 ± 13.7 mWatt/m 2 , and 8.28 ± 10.4%, respectively. The results suggest that the presence of Typha angustifolia vegetation in the CW-MFC matrix provides the benefits for treatment efficiency and bioelectric production; thus, it increases microbial activities which are responsible for biodegradation of organic compounds and catalyzed to electron flow from anode to cathode. Consequently, we suggest that engineers can use vegetated wetland matrix with Typha angustifolia in CW-MFC module in order to maximize treatment efficiency and bioelectric production.

Real-Time Optical Image Processing Techniques

DTIC Science & Technology

1988-10-31

pursued through the analysis, design, and fabrication of pulse frequency modulated halftone screens and the modification of micro-chan- nel spatial...required for non-linear operation. Real-time nonlinear processing was performed using the halftone screen and MSLM. The experiments showed the effectiveness...pulse frequency modulation has been pursued through the analysis, design, and fabrication of pulse frequency modulated halftone screens and the

Biomedical Potential of mTOR Modulation by Nanoparticles.

PubMed

Hulea, Laura; Markovic, Zoran; Topisirovic, Ivan; Simmet, Thomas; Trajkovic, Vladimir

2016-05-01

Modulation of the mammalian target of rapamycin (mTOR), the principal regulator of cellular homeostasis, underlies the biological effects of engineered nanoparticles, including regulation of cell death/survival and metabolic responses. Understanding the mechanisms and biological actions of nanoparticle-mediated mTOR modulation may help in developing safe and efficient nanotherapeutics to fight human disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of Staff Training on Staff Knowledge and Attitudes about Sexuality.

ERIC Educational Resources Information Center

Walker, Bonnie L.; Harrington, Donna

2002-01-01

Four learning modules on elderly sexuality were pilot tested with 109 long-term care staff. On pretests men and whites scored higher than women and African-Americans. Knowledge and attitude improvements resulted from use of modules on the need for sexuality/intimacy, sex and dementia, and sex and aging, but not the family/personal issues module.…