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Sample records for frequency transformer linked

  1. High-frequency broadband transformers

    NASA Astrophysics Data System (ADS)

    London, S. E.; Tomashevich, S. V.

    1981-05-01

    A systematic review of the theory and design principles of high-frequency broadband transformers is presented. It is shown that the transformers of highest performance are those whose coils consist of strips of double-wire and multiwire transmission lines. Such devices are characterized by a wide operating frequency range, and make possible operation at microwave frequencies at high levels of transmitted power.

  2. Lightweight, high-frequency transformers

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.

    1983-01-01

    The 25-kVA space transformer was developed under contract by Thermal Technology Laboratory, Buffalo, N. Y. The NASA Lewis transformer technology program attempted to develop the baseline technology. For the 25-kVA transformer the input voltage was chosen as 200 V, the output voltage as 1500 V, the input voltage waveform as square wave, the duty cycle as continuous, the frequency range (within certain constraints) as 10 to 40 kHz, the operating temperatures as 85 deg. and 130 C, the baseplate temperature as 50 C, the equivalent leakage inductance as less than 10 micro-h, the operating environment as space, and the life expectancy as 10 years. Such a transformer can also be used for aircraft, ship and terrestrial applications.

  3. Fiber optic frequency transfer link

    NASA Technical Reports Server (NTRS)

    Primas, Lori E. (Inventor); Sydnor, Richard L. (Inventor); Lutes, George F. (Inventor)

    1991-01-01

    A reference frequency distribution system is disclosed for transmitting a reference frequency from a reference unit to a remote unit while keeping the reference frequency at the reference unit and the remote unit in phase. A fiber optic cable connects the reference unit to the remote unit. A frequency source at the reference unit produces a reference frequency having an adjustable phase. A fiber optic transmitter at the reference unit modulates a light beam with the reference frequency and transmits the light beam into the fiber optic cable. A 50/50 reflector at the remote unit reflects a first portion of the light beam from the reference unit back into the fiber optic cable to the reference unit. A first fiber optic receiver disposed at the remote unit receives a second portion of the light beam and demodulates the reference frequency to be used at the remote unit. A second fiber optic receiver disposed at the reference unit receives the first portion of the light beam and demodulates a reference frequency component. A phase conjugator is connected to the frequency source for comparing the phase of the reference frequency component to the phase of the reference frequency modulating the light beam being transmitted from the reference unit to maintain a conjugate (anti-symmetric) relationship between the reference frequency component and the reference frequency modulating the light beam where virtually no phase difference exists between the phase of the reference frequency component and the phase of the reference frequency modulating the light beam.

  4. Computing Instantaneous Frequency by normalizing Hilbert Transform

    NASA Technical Reports Server (NTRS)

    Huang, Norden E. (Inventor)

    2005-01-01

    This invention presents Normalized Amplitude Hilbert Transform (NAHT) and Normalized Hilbert Transform(NHT), both of which are new methods for computing Instantaneous Frequency. This method is designed specifically to circumvent the limitation set by the Bedorsian and Nuttal Theorems, and to provide a sharp local measure of error when the quadrature and the Hilbert Transform do not agree. Motivation for this method is that straightforward application of the Hilbert Transform followed by taking the derivative of the phase-angle as the Instantaneous Frequency (IF) leads to a common mistake made up to this date. In order to make the Hilbert Transform method work, the data has to obey certain restrictions.

  5. Computing Instantaneous Frequency by normalizing Hilbert Transform

    DOEpatents

    Huang, Norden E.

    2005-05-31

    This invention presents Normalized Amplitude Hilbert Transform (NAHT) and Normalized Hilbert Transform(NHT), both of which are new methods for computing Instantaneous Frequency. This method is designed specifically to circumvent the limitation set by the Bedorsian and Nuttal Theorems, and to provide a sharp local measure of error when the quadrature and the Hilbert Transform do not agree. Motivation for this method is that straightforward application of the Hilbert Transform followed by taking the derivative of the phase-angle as the Instantaneous Frequency (IF) leads to a common mistake made up to this date. In order to make the Hilbert Transform method work, the data has to obey certain restrictions.

  6. Electrocardiogram Signal and Linear Time-Frequency Transforms

    NASA Astrophysics Data System (ADS)

    Krishna, B. T.

    2014-12-01

    The diagnostic analysis of non-stationary multi component signals such as electrocardiogram (ECG) involves the use of time-frequency transforms. So, the application of time-frequency transforms to an ECG signal is an important problem of research. In this paper, initially, linear transforms like short time Fourier transform, continuous wavelet transforms, s-transform etc. are revisited. Then the application of these transforms to normal and abnormal ECG signals is illustrated. It has been observed that s-transform provides better time and frequency resolution compared to other linear transforms. The fractional Fourier transform provides rotation to the spectrogram representation.

  7. Precise verification of a fibre link for frequency transfer

    NASA Astrophysics Data System (ADS)

    Matthee, C. F.; Burger, J. P.; Kritzinger, R.

    2014-06-01

    A new electrically insensitive optical fibre link was installed between two buildings using commercially available equipment. The aim of the link was to transfer the frequency accuracy from the South African National Measure- ment Standard for Time and Frequency (derived from caesium atomic clocks) to an optical frequency comb. This enables direct traceability of optical frequency measurements to internationally verified time standards (UTC), via the timing links at the National Metrology Institute of South Africa (NMISA). A clean-up oscillator is used to improve any degrading of the stability caused by the laser link. Highly precise loop-back experiments were done to verify the accuracy and stability of the fibre link and clean-up oscillator combination. The nature and results of such experiments are presented here, in order to demonstrate the traceability of the fibre link, and therefore the traceable link between the optical frequency comb and the National Measurement Standards for Time and Frequency of South Africa.

  8. Experimental radio frequency link for Ka-band communications applications

    NASA Technical Reports Server (NTRS)

    Fujikawa, Gene; Conray, Martin J.; Saunders, Alan L.; Pope, Dale E.

    1988-01-01

    An experimental radio frequency link has been demonstrated to provide two-way communication between a remote user ground terminal and a ground-based Ka-band transponder. Bit-error-rate performance and radio frequency characteristics of the communication link were investigated.

  9. A New Instantaneous Frequency Measure Based on The Stockwell Transform

    NASA Astrophysics Data System (ADS)

    yedlin, M. J.; Ben-Horrin, Y.; Fraser, J. D.

    2011-12-01

    We propose the use of a new transform, the Stockwell transform[1], as a means of creating time-frequency maps and applying them to distinguish blasts from earthquakes. This new transform, the Stockwell transform can be considered as a variant of the continuous wavelet transform, that preserves the absolute phase.The Stockwell transform employs a complex Morlet mother wavelet. The novelty of this transform lies in its resolution properties. High frequencies in the candidate signal are well-resolved in time but poorly resolved in frequency, while the converse is true for low frequency signal components. The goal of this research is to obtain the instantaneous frequency as a function of time for both the earthquakes and the blasts. Two methods will be compared. In the first method, we will compute the analytic signal, the envelope and the instantaneous phase as a function of time[2]. The instantaneous phase derivative will yield the instantaneous angular frequency. The second method will be based on time-frequency analysis using the Stockwell transform. The Stockwell transform will be computed in non-redundant fashion using a dyadic representation[3]. For each time-point, the frequency centroid will be computed -- a representation for the most likely frequency at that time. A detailed comparison will be presented for both approaches to the computation of the instantaneous frequency. An advantage of the Stockwell approach is that no differentiation is applied. The Hilbert transform method can be less sensitive to edge effects. The goal of this research is to see if the new Stockwell-based method could be used as a discriminant between earthquakes and blasts. References [1] Stockwell, R.G., Mansinha, L. and Lowe, R.P. "Localization of the complex spectrum: the S transform", IEEE Trans. Signal Processing, vol.44, no.4, pp.998-1001, (1996). [2]Taner, M.T., Koehler, F. "Complex seismic trace analysis", Geophysics, vol. 44, Issue 6, pp. 1041-1063 (1979). [3] Brown, R

  10. A high frequency transformer model for the EMTP

    SciTech Connect

    Morched, A.; Marti, L.; Ottevangers, J. )

    1993-07-01

    A model to simulate the high frequency behavior of a power transformer is presented. This model is based on the frequency characteristics of the transformer admittance matrix between its terminals over a given range of frequencies. The transformer admittance characteristics can be obtained from measurements or from detailed internal models based on the physical layout of the transformer. The elements of the nodal admittance matrix are approximated with rational functions consisting of real as well as complex conjugate poles and zeros. These approximations are realized in the form of an RLC network in a format suitable for direct use with EMTP. The high frequency transformer model can be used as a stand-alone linear model or as an add-on module of a more comprehensive model where iron core nonlinearities are represented in detail.

  11. Attenuation estimation using the peak frequency method with high-resolution time-frequency transforms

    NASA Astrophysics Data System (ADS)

    Tary, J. B.; Van der Baan, M.; Herrera, R. H.

    2016-12-01

    Seismic waves attenuate during their propagation due to Earth anelasticity. Attenuation is usually estimated by frequency domain methods such as the spectral ratio and frequency shift methods. These methods compare large frequency bandwidths of the spectra of two waveforms to compute attenuation. Time-frequency distribution resulting from high-resolution time-frequency transforms are highly localized which prevent their use to compute attenuation with these methods.The peak frequency method only requires the estimation of peak frequencies for a pair of waveforms to estimate attenuation, which is then compatible with high-resolution transforms. We here employ three transforms, namely basis pursuit, synchrosqueezing transform, and complete ensemble empirical mode decomposition (CEEMD). We evaluate their performance regarding attenuation estimation using synthetic examples with different signal-to-noise ratios, and compare their results to those of the spectral ratio and frequency shift methods. In most cases basis pursuit and the synchrosqueezing transform provide accurate results, while CEEMD show a higher sensitivity to the presence of noise.We then apply the three high-resolution transforms and the peak frequency method to two case studies, a seismic reflection profile and a vertical seismic profile (VSP). We employ centroid frequencies instead of peak frequencies because they provide stabler frequency estimates which are then transferred to stabler attenuation estimates. In the case of the seismic reflection profile, the three time-frequency transforms show small increases in centroid frequencies superimposed on a general decreasing trend. This likely corresponds to local tuning effects due to the layering superimposed on the effect of intrinsic attenuation. For the VSP, the three time-frequency transforms show consistent patterns in centroid frequencies and quality factors. These results show the worth of high-resolution transforms for attenuation estimation.

  12. Epstein–Barr Virus: Diseases Linked to Infection and Transformation

    PubMed Central

    Jha, Hem C.; Pei, Yonggang; Robertson, Erle S.

    2016-01-01

    Epstein–Barr virus (EBV) was first discovered in 1964, and was the first known human tumor virus now shown to be associated with a vast number of human diseases. Numerous studies have been conducted to understand infection, propagation, and transformation in various cell types linked to human diseases. However, a comprehensive lens through which virus infection, reactivation and transformation of infected host cells can be visualized is yet to be formally established and will need much further investigation. Several human cell types infected by EBV have been linked to associated diseases. However, whether these are a direct result of EBV infection or indirectly due to contributions by additional infectious agents will need to be fully investigated. Therefore, a thorough examination of infection, reactivation, and cell transformation induced by EBV will provide a more detailed view of its contributions that drive pathogenesis. This undoubtedly expand our knowledge of the biology of EBV infection and the signaling activities of targeted cellular factors dysregulated on infection. Furthermore, these insights may lead to identification of therapeutic targets and agents for clinical interventions. Here, we review the spectrum of EBV-associated diseases, the role of the encoded latent antigens, and the switch to latency or lytic replication which occurs in EBV infected cells. Furthermore, we describe the cellular processes and critical factors which contribute to cell transformation. We also describe the fate of B-cells and epithelial cells after EBV infection and the expected consequences which contribute to establishment of viral-associated pathologies. PMID:27826287

  13. Frequency-dependent FDTD methods using Z transforms

    NASA Technical Reports Server (NTRS)

    Sullivan, Dennis M.

    1992-01-01

    While the frequency-dependent finite-difference time-domain, or (FD)2TD, method can correctly calculate EM propagation through media whose dielectric properties are frequency-dependent, more elaborate applications lead to greater (FD)2TD complexity. Z-transform theory is presently used to develop the mathematical bases of the (FD)2TD method, simultaneously obtaining a clearer formulation and allowing researchers to draw on the existing literature of systems analysis and signal-processing.

  14. Wideband image demodulation via bi-dimensional multirate frequency transformations.

    PubMed

    Liu, Wenjing; Santhanam, Balu

    2016-09-01

    Existing image demodulation approaches based on the two-dimensional (2D) multicomponent AM-FM model assume narrowband components that can be demodulated using energy operators, Hilbert transforms, or the monogenic image approaches. However, if the FM components are wideband, then these demodulation approaches incur significant errors. Recent work by the authors extended wideband FM demodulation in one dimension to accommodate large conversion factors using multirate frequency transformations. In this paper, we extend the multirate frequency transformations technique developed for one-dimensional signals to 2D and images in conjunction with a recently proposed 2D higher-order energy demodulation approach. This extension is applied to both synthetic and real images to demonstrate the efficacy of the approach.

  15. Time-frequency representation measurement based on temporal Fourier transformation

    NASA Astrophysics Data System (ADS)

    Suen, Yifan; Xiao, Shaoqiu; Hao, Sumin; Zhao, Xiaoxiang; Xiong, Yigao; Liu, Shenye

    2016-10-01

    We propose a new scheme to physically realize the short-time Fourier transform (STFT) of chirped optical pulse using time-lens array that enables us to get time-frequency representation without using FFT algorithm. The time-lens based upon the four-wave mixing is used to perform the process of temporal Fourier transformation. Pump pulse is used for both providing the quadratic phase and being the window function of STFT. The idea of STFT is physically realized in our scheme. Simulations have been done to investigate performance of the time-frequency representation scheme (TFRS) in comparison with STFT using FFT algorithm. Optimal measurement of resolution in time and frequency has been discussed.

  16. Ultrasonic transformation of micelle structures: effect of frequency and power.

    PubMed

    Yusof, Nor Saadah Mohd; Ashokkumar, Muthupandian

    2015-05-01

    A comprehensive investigation on the effect of ultrasonic frequency and power on the structural transformation of CTABr/NaSal micelles has been carried out. Sonication of this micelle system at various ultrasonic frequencies and power resulted in the formation and separation of two types of micelles. High viscoelastic threadlike micelles of ∼ 2 nm in diameter and several μm in length and tubular micelles possessing a viscosity slightly above that of water with ∼ 30-50 nm diameter and few hundred nm length. The structural transformation of micelles was induced by the shear forces generated during acoustic cavitation. At a fixed acoustic power of 40 W, the structural transformation was found to decrease from 211 to 647 kHz frequency due to the decreasing shear forces generated, as evidenced by rheological measurements and cryo-TEM images. At 355 kHz, an increase in the structural transformation was observed with an increase in acoustic power. These findings provide a knowledge base that could be useful for the manipulation of viscosity of micelles that may have applications in oil industry.

  17. Intermittent optical frequency measurements to reduce the dead time uncertainty of frequency link

    NASA Astrophysics Data System (ADS)

    Hachisu, Hidekazu; Ido, Tetsuya

    2015-11-01

    The absolute frequency of the 87Sr lattice clock transition was evaluated with an uncertainty of 1.1 × 10-15 using a frequency link to the international atomic time (TAI). The frequency uncertainty of a hydrogen maser used as a transfer oscillator was reduced by homogeneously distributed intermittent measurement over a five-day grid of TAI. Three sets of four or five days measurements as well as systematic uncertainty of the clock at 8.6 × 10-17 have resulted in an absolute frequency of 87Sr 1S0-3P0 clock transition to be 429 228 004 229 872.85 (47) Hz.

  18. A versatile power converter for high-frequency link systems

    NASA Technical Reports Server (NTRS)

    Sood, Pradeep K.; Lipo, Thomas A.; Hansen, Irving G.

    1988-01-01

    A single-phase HF link appears to be an attractive alternative to the dc link commonly used in power conversion systems. Here, a power converter suitable for one-step conversion of the single-phase HF link voltage to the three-phase LF voltages typically required for interfacing with system sources and loads is proposed. The converter utilizes zero-voltage switching principles to minimize switching losses and an easy-to-implement technique of pulse-density modulation for the control of the amplitude, frequency, and waveshape of the synthesized LF signals. Adaptation of the proposed topology for power conversion to single-phase ac and dc voltage or current outputs is shown to be straightforward. The feasibility of the proposed power circuit and the control technique has been experimentally verified.

  19. Frequency Correction for MIRO Chirp Transformation Spectroscopy Spectrum

    NASA Technical Reports Server (NTRS)

    Lee, Seungwon

    2012-01-01

    This software processes the flyby spectra of the Chirp Transform Spectrometer (CTS) of the Microwave Instrument for Rosetta Orbiter (MIRO). The tool corrects the effect of Doppler shift and local-oscillator (LO) frequency shift during the flyby mode of MIRO operations. The frequency correction for CTS flyby spectra is performed and is integrated with multiple spectra into a high signal-to-noise averaged spectrum at the rest-frame RF frequency. This innovation also generates the 8 molecular line spectra by dividing continuous 4,096-channel CTS spectra. The 8 line spectra can then be readily used for scientific investigations. A spectral line that is at its rest frequency in the frame of the Earth or an asteroid will be observed with a time-varying Doppler shift as seen by MIRO. The frequency shift is toward the higher RF frequencies on approach, and toward lower RF frequencies on departure. The magnitude of the shift depends on the flyby velocity. The result of time-varying Doppler shift is that of an observed spectral line will be seen to move from channel to channel in the CTS spectrometer. The direction (higher or lower frequency) in the spectrometer depends on the spectral line frequency under consideration. In order to analyze the flyby spectra, two steps are required. First, individual spectra must be corrected for the Doppler shift so that individual spectra can be superimposed at the same rest frequency for integration purposes. Second, a correction needs to be applied to the CTS spectra to account for the LO frequency shifts that are applied to asteroid mode.

  20. Time frequency chirp-Wigner transform for signals with any nonlinear polynomial time varying instantaneous frequency

    NASA Astrophysics Data System (ADS)

    Gelman, L.; Gould, J. D.

    2007-11-01

    The new technique, the time-frequency chirp-Wigner transform has been proposed recently. This technique is further investigated for the general case of higher order chirps, i.e. non-stationary signals with any nonlinear polynomial variation of the instantaneous frequency in time. Analytical and numerical comparison of the chirp-Wigner transform and the classical Wigner distribution was performed for processing of single-component and multi-component higher order chirps. It is shown for the general case of single component higher order chirps that the chirp-Wigner transform has an essential advantage in comparison with the traditional Wigner distribution: the chirp-Wigner transform ideally follows the nonlinear polynomial frequency variation without amplitude errors. It is shown for multi-component signal where each component is a higher order chirp, that the chirp-Wigner transform adjusted to a single component will follow the instantaneous frequency of the component without amplitude errors. It is also shown that the classical Wigner distribution is unable to estimate component amplitudes of single component and multi-component higher order chirps.

  1. Double wavelet transform of frequency-modulated nonstationary signal

    NASA Astrophysics Data System (ADS)

    Bozhokin, S. V.; Suslova, I. M.

    2013-12-01

    A mathematical model is proposed for a frequency-modulated signal in the form of a system of Gaussian peaks randomly distributed in time. An analytic expression is obtained for continuous wavelet transform (CWT) of the model signal. For signals with time-varying sequence of peaks, the main ridge of the skeleton characterized by frequency ν{max/MFB} ( t) is analyzed. The value of ν{max/MFB} ( t) is determined for any instant t from the condition of the CWT maximum in the spectral range of the main frequency band (MFB). Double CWT of function ν{max/MFB} ( t) is calculated for a frequency-modulated signal with a transition regions of smooth frequency variation (trend) as well as with varying frequency oscillations relative to the trend. The duration of transition periods of the signal is determined using spectral integrals E ν( t). The instants of emergence and decay of low-frequency spectral components of the signal are determined. The double CWT method can be used for analyzing cardiac rhythms and neural activity, as well as nonstationary processes in quantum radio physics and astronomy.

  2. Precision Fourier Transform Spectroscopy with Femtosecond Frequency Combs

    NASA Astrophysics Data System (ADS)

    Jacquet, P.; Mandon, J.; Guelachvili, G.; Picqué, N.; Bernhardt, B.; Holzwarth, R.; Hänsch, T. W.

    2009-06-01

    Fourier transform spectrometers play a crucial and intensive role in molecular spectroscopy. However, these instruments, most often based on Michelson interferometers, are presently unable to address some of the new challenges associated with fundamental experiments or optical diagnostic. In recent years, femtosecond frequency combs, which are new laser sources exhibiting an optical spectrum made of very sharp and uniformly spaced lines, have revolutionized the field of frequency metrology. They lead also to the implementation of a new kind of Fourier interferometers, where two frequency combs with slightly different repetition rates beat with each other. These spectrometers may bring remarkable characteristics, amongst which extremely short measurement time. We report on the implementation of an original and simple set-up for frequency comb Fourier transform spectroscopy, which reaches the unprecedented resolution of 1 kHz within 6 s recording time. Moving mirror of equivalent Michelson interferometers should cover 130 km path-difference excursion at 10 km.s^{-1} velocity. We also record simultaneously Doppler-limited dispersion and absorption spectra within a few tens of microseconds. The comb structure of the light source provides self-calibration of the wavenumber scale. Precision spectroscopy of the overtone spectrum of acetylene, in the 1.5 μm range, is reported as a first demonstration.

  3. Hilbert-Huang transformation-based time-frequency analysis methods in biomedical signal applications.

    PubMed

    Lin, Chin-Feng; Zhu, Jin-De

    2012-03-01

    Hilbert-Huang transformation, wavelet transformation, and Fourier transformation are the principal time-frequency analysis methods. These transformations can be used to discuss the frequency characteristics of linear and stationary signals, the time-frequency features of linear and non-stationary signals, the time-frequency features of non-linear and non-stationary signals, respectively. The Hilbert-Huang transformation is a combination of empirical mode decomposition and Hilbert spectral analysis. The empirical mode decomposition uses the characteristics of signals to adaptively decompose them to several intrinsic mode functions. Hilbert transforms are then used to transform the intrinsic mode functions into instantaneous frequencies, to obtain the signal's time-frequency-energy distributions and features. Hilbert-Huang transformation-based time-frequency analysis can be applied to natural physical signals such as earthquake waves, winds, ocean acoustic signals, mechanical diagnosis signals, and biomedical signals. In previous studies, we examined Hilbert-Huang transformation-based time-frequency analysis of the electroencephalogram FPI signals of clinical alcoholics, and 'sharp I' wave-based Hilbert-Huang transformation time-frequency features. In this paper, we discuss the application of Hilbert-Huang transformation-based time-frequency analysis to biomedical signals, such as electroencephalogram, electrocardiogram signals, electrogastrogram recordings, and speech signals.

  4. Frequency transformation in the auditory lemniscal thalamocortical system.

    PubMed

    Imaizumi, Kazuo; Lee, Charles C

    2014-01-01

    The auditory lemniscal thalamocortical (TC) pathway conveys information from the ventral division of the medial geniculate body to the primary auditory cortex (A1). Although their general topographic organization has been well characterized, functional transformations at the lemniscal TC synapse still remain incompletely codified, largely due to the need for integration of functional anatomical results with the variability observed with various animal models and experimental techniques. In this review, we discuss these issues with classical approaches, such as in vivo extracellular recordings and tracer injections to physiologically identified areas in A1, and then compare these studies with modern approaches, such as in vivo two-photon calcium imaging, in vivo whole-cell recordings, optogenetic methods, and in vitro methods using slice preparations. A surprising finding from a comparison of classical and modern approaches is the similar degree of convergence from thalamic neurons to single A1 neurons and clusters of A1 neurons, although, thalamic convergence to single A1 neurons is more restricted from areas within putative thalamic frequency lamina. These comparisons suggest that frequency convergence from thalamic input to A1 is functionally limited. Finally, we consider synaptic organization of TC projections and future directions for research.

  5. Amplifying Student Voice: The Missing Link in School Transformation

    ERIC Educational Resources Information Center

    Beattie, Helen

    2012-01-01

    This article recounts the story of how one state in the United States is systematically amplifying student voice through school transformation efforts across a network of secondary schools (Grades 9 through 12; ages 14 to 18). The author is the creator and director of a statewide initiative entitled "Youth and Adults Transforming Schools Together"…

  6. A Unified Approach to IRT Scale Linking and Scale Transformations. Research Report. RR-04-09

    ERIC Educational Resources Information Center

    von Davier, Matthias; von Davier, Alina A.

    2004-01-01

    This paper examines item response theory (IRT) scale transformations and IRT scale linking methods used in the Non-Equivalent Groups with Anchor Test (NEAT) design to equate two tests, X and Y. It proposes a unifying approach to the commonly used IRT linking methods: mean-mean, mean-var linking, concurrent calibration, Stocking and Lord and…

  7. Laminar transformation of frequency organization in auditory cortex.

    PubMed

    Winkowski, Daniel E; Kanold, Patrick O

    2013-01-23

    The mammalian neocortex is a six-layered structure organized into radial columns. Within sensory cortical areas, information enters in the thalamorecipient layer and is further processed in supragranular and infragranular layers. Within the neocortex, topographic maps of stimulus features are present, but whether topographic patterns of active neurons change between laminae is unknown. Here, we used in vivo two-photon Ca(2+) imaging to probe the organization of the mouse primary auditory cortex and show that the spatial organization of neural response properties (frequency tuning) within the thalamorecipient layer (L3b/4) is more homogeneous than in supragranular layers (L2/3). Moreover, stimulus-related correlations between pairs of neurons are higher in the thalamorecipient layer, whereas stimulus-independent trial-to-trial covariance is higher in supragranular neurons. These findings reveal a transformation of sensory representations that occurs between layers within the auditory cortex, which could generate sequentially more complex analysis of the acoustic scene incorporating a broad range of spectrotemporal sound features.

  8. Noise reduction combining time-frequency epsilon-filter and M-transform.

    PubMed

    Abe, Tomomi; Matsumoto, Mitsuharu; Hashimoto, Shuji

    2008-08-01

    This paper introduces noise reduction combining time-frequency epsilon-filter (TF epsilon-filter) and time-frequency M-transform (TF M-transform). Musical noise is an offensive noise generated due to noise reduction in the time-frequency domain such as spectral subtraction and TF epsilon-filter. It has a deleterious effect on speech recognition. To solve the problem, M-transform is introduced. M-transform is a linear transform based on M-sequence. The method combining the time-domain epsilon-filter (TD epsilon-filter) and time-domain M-transform (TD M-transform) can reduce not only white noise but also impulse noise. Musical noise is isolated in the time-frequency domain, which is similar to impulse noise in the time domain. On these prospects, this paper aims to reduce musical noise by improving M-transform for the time-frequency domain. Noise reduction by using TD M-transform and the TD epsilon-filter is first explained to clarify its features. Then, an improved method applying M-transform to the time-frequency domain, namely TF M-transform, is described. Noise reduction combining the TF epsilon-filter and TF M-transform is also proposed. The proposed method can reduce not only high-level nonstationary noise but also musical noise. Experimental results are also given to demonstrate the performance of the proposed method.

  9. Generalised relativistic Ohm's laws, extended gauge transformations, and magnetic linking

    SciTech Connect

    Pegoraro, F.

    2015-11-15

    Generalisations of the relativistic ideal Ohm's law are presented that include specific dynamical features of the current carrying particles in a plasma. Cases of interest for space and laboratory plasmas are identified where these generalisations allow for the definition of generalised electromagnetic fields that transform under a Lorentz boost in the same way as the real electromagnetic fields and that obey the same set of homogeneous Maxwell's equations.

  10. Generalised relativistic Ohm's laws, extended gauge transformations, and magnetic linking

    NASA Astrophysics Data System (ADS)

    Pegoraro, F.

    2015-11-01

    Generalisations of the relativistic ideal Ohm's law are presented that include specific dynamical features of the current carrying particles in a plasma. Cases of interest for space and laboratory plasmas are identified where these generalisations allow for the definition of generalised electromagnetic fields that transform under a Lorentz boost in the same way as the real electromagnetic fields and that obey the same set of homogeneous Maxwell's equations.

  11. A simple structure wavelet transform circuit employing function link neural networks and SI filters

    NASA Astrophysics Data System (ADS)

    Mu, Li; Yigang, He

    2016-12-01

    Signal processing by means of analog circuits offers advantages from a power consumption viewpoint. Implementing wavelet transform (WT) using analog circuits is of great interest when low-power consumption becomes an important issue. In this article, a novel simple structure WT circuit in analog domain is presented by employing functional link neural network (FLNN) and switched-current (SI) filters. First, the wavelet base is approximated using FLNN algorithms for giving a filter transfer function that is suitable for simple structure WT circuit implementation. Next, the WT circuit is constructed with the wavelet filter bank, whose impulse response is the approximated wavelet and its dilations. The filter design that follows is based on a follow-the-leader feedback (FLF) structure with multiple output bilinear SI integrators and current mirrors as the main building blocks. SI filter is well suited for this application since the dilation constant across different scales of the transform can be precisely implemented and controlled by the clock frequency of the circuit with the same system architecture. Finally, to illustrate the design procedure, a seventh-order FLNN-approximated Gaussian wavelet is implemented as an example. Simulations have successfully verified that the designed simple structure WT circuit has low sensitivity, low-power consumption and litter effect to the imperfections.

  12. Gramian-Preserving Frequency Transformation for Linear Discrete-Time State-Space Systems

    NASA Astrophysics Data System (ADS)

    Koshita, Shunsuke; Tanaka, Satoru; Abe, Masahide; Kawamata, Masayuki

    This paper proposes the Gramian-preserving frequency transformation for linear discrete-time state-space systems. In this frequency transformation, we replace each delay element of a discrete-time system with an allpass system that has a balanced realization. This approach can generate transformed systems that have the same controllability/observability Gramians as those of the original system. From this result, we show that the Gramian-preserving frequency transformation gives us transformed systems with different magnitude characteristics, but with the same structural property with respect to the Gramians as that of the original system. This paper also presents a simple method for realization of the Gramian-preserving frequency transformation. This method makes use of the cascaded normalized lattice structure of allpass systems.

  13. High-frequency transformation of Brevibacterium lactofermentum protoplasts by plasmid DNA.

    PubMed

    Santamaria, R I; Gil, J A; Martin, J F

    1985-04-01

    An efficient polyethylene glycol-assisted method for transformation of Brevibacterium lactofermentum protoplasts that uses plasmid vectors has been developed. Two small plasmids, pUL330 (5.2 kilobases) and pUL340 (5.8 kilobases), both containing the kanamycin resistance gene from transposon Tn5 and the replication origin of the natural plasmid pBL1 of B. lactofermentum, were selected as vectors. Supercoiled forms of the plasmids yielded a 100-fold higher transformation frequency than did linear forms. The optimal transformation frequency was achieved with 10 ng of DNA in 1 ml of transformation buffer. Higher concentrations of plasmid DNA resulted in a decrease in transformation frequency per microgram of DNA. Optimal transformation was obtained with 25 to 35% polyethylene glycol 6000. Under optimal conditions, 10(6) transformants per microgram of DNA were obtained.

  14. Frequency Spectrum for New Aviation Data Links: Initial Study Results

    NASA Technical Reports Server (NTRS)

    Matolak, David W.; Branstetter, James R.

    2004-01-01

    We describe results from an initial study to assess the suitability of various spectral bands for supporting the deployment of new aviation data links (ADL). The study focused on systems and spectral bands that can deliver VHF data link (VDL)-or-higher data rates in a two-way communication setting, including air-ground, ground-air, and air-air modes of operation. In the first part of our paper, we briefly discuss the current situation regarding communications, navigation, and surveillance (CNS) links and existing spectrum, and the well-known need for new aviation data links. We next provide an overview of related systems, and discuss key factors involved in the use of spectrum in various bands for any future integrated CNS data link, addressing primarily the lower few layers of the communications protocol stack. Desired attributes of a new ADL system are discussed, and the beneficial aspects of a particular transmission technique spread spectrum are summarized. We also provide a short list of several example potential spectral regions, and note that while none of the existing systems will likely meet the full range of desired features of a new ADL, several systems and spectral regions offer promise in terms of one or more characteristics. A detailed discussion and evaluation of these spectral regions is proposed as future work. We include a few brief examples to illustrate initial technical results regarding spread spectrum overlay, also a subject for future work.

  15. A genetic link between transform and hyper-extended margins

    NASA Astrophysics Data System (ADS)

    Le Pourhiet, Laetitia; May, Dave A.; Huille, Lucas; Watremez, Louise; Leroy, Sylvie

    2017-05-01

    The similarity between the geometry of the West African and South American coastlines is among one of the strongest natural observations supporting the plate tectonic paradigm. However, using classical plate tectonic approaches to model these conjugate transform margins results in a high degree of variability in palaeogeographic reconstructions. Using state-of-the-art 3D coupled thermo-mechanical numerical models, we simulate for the first time, crustal deformation at the onset of oceanisation along large offset oblique margins. Our models show that obliquity causes oceanic rift propagation to stall, resulting in an apparent polyphased tectonic evolution, and in some circumstances leads to the formation of hyper-extended margins. As a result, conjugate margins located at the edge of future fracture zones are highly asymmetric from rifting to spreading, with their lengths differing by a factor of 5 to 10, before the final phase of break-up occurs. Accounting for this discrepancy should ameliorate future palaeogeographic reconstructions.

  16. Development Of Frequency Transfer Via Optical Fiber Link at NICT

    DTIC Science & Technology

    2008-12-01

    al., 2006 “Comparison between frequency standards in Europe and the USA at the 10-15 uncertainty level,” Metrologia , 43, 109-120. [4] H. Kiuchi, T...M. Hosokawa, 2008, “Evaluation of caesium atomic fountain NICT-CsF1,” Metrologia , 45, 139-148. [12] M. Kumagai, H. Ito, G. Santarelli, C. Locke, J

  17. A four-quadrant current regulated converter with a high-frequency link

    SciTech Connect

    Ziogas, P.D.; Ranganathan, V.T.; Stefanovic, V.R.

    1982-09-01

    A novel and highly versatile four-quadrant static converter is discussed. A resonant high frequency link is employed which provides an extremely fast response to external commands and a wide frequency range of converter operation. This converter is therefore very suitable for four-quadrant dc chopper and constant or variable frequency inverter applications.

  18. Frequency Agile Transceiver for Advanced Vehicle Data Links

    NASA Technical Reports Server (NTRS)

    Freudinger, Lawrence C.; Macias, Filiberto; Cornelius, Harold

    2009-01-01

    Emerging and next-generation test instrumentation increasingly relies on network communication to manage complex and dynamic test scenarios, particularly for uninhabited autonomous systems. Adapting wireless communication infrastructure to accommodate challenging testing needs can benefit from reconfigurable radio technology. Frequency agility is one characteristic of reconfigurable radios that to date has seen only limited progress toward programmability. This paper overviews an ongoing project to validate a promising chipset that performs conversion of RF signals directly into digital data for the wireless receiver and, for the transmitter, converts digital data into RF signals. The Software Configurable Multichannel Transceiver (SCMT) enables four transmitters and four receivers in a single unit, programmable for any frequency band between 1 MHz and 6 GHz.

  19. Parametric frequency transformation in a superconducting waveguide line with an integrated Josephson oscillator

    NASA Astrophysics Data System (ADS)

    Denisenko, M. V.; Munyaev, V. O.; Satanin, A. M.

    2016-11-01

    The parametric frequency division in a coplanar waveguide line with an integrated single-contact rf SQUID (Josephson oscillator) is discussed. It is assumed that the oscillator is excited by pump pulses whose carrier frequency can be a multiple of the plasma frequency of the oscillator. It is shown that the Josephson oscillator excited at the pump frequency can induce frequency division by emitting subharmonics that are multiples of the fundamental frequency (fractional resonances). Parameters for which parametric frequency transformation occurs are determined. The possible generalization of this effect to the quantum case in which correlated microwave photons (entangled photon states) can be generated is discussed.

  20. DC-link approach to constant-frequency aircraft power

    NASA Technical Reports Server (NTRS)

    Yorksi, D. S.

    1983-01-01

    This paper discusses a hybrid high-power aircraft electrical system that has very difficult and complex operating requirements. Many issues raised in selecting an approach for this application are similar to those that must eventually be addressed for a large all-electric aircraft. The requirements for this specific system are reviewed, a solution for those requirements is proposed, and some explanation is provided for the choice. Because the system requires a substantial amount of 400-Hz power, a dc-link system was selected to provide that power.

  1. DC-link approach to constant-frequency aircraft power

    NASA Astrophysics Data System (ADS)

    Yorksi, D. S.

    1983-06-01

    This paper discusses a hybrid high-power aircraft electrical system that has very difficult and complex operating requirements. Many issues raised in selecting an approach for this application are similar to those that must eventually be addressed for a large all-electric aircraft. The requirements for this specific system are reviewed, a solution for those requirements is proposed, and some explanation is provided for the choice. Because the system requires a substantial amount of 400-Hz power, a dc-link system was selected to provide that power.

  2. Design-oriented analytic model of phase and frequency modulated optical links

    NASA Astrophysics Data System (ADS)

    Monsurrò, Pietro; Saitto, Antonio; Tommasino, Pasquale; Trifiletti, Alessandro; Vannucci, Antonello; Cimmino, Rosario F.

    2016-07-01

    An analytic design-oriented model of phase and frequency modulated microwave optical links has been developed. The models are suitable for design of broadband high dynamic range optical links for antenna remoting and optical beamforming, where noise and linearity of the subsystems are a concern Digital filter design techniques have been applied to the design of optical filters working as frequency discriminator, that are the bottleneck in terms of linearity for these systems. The models of frequency modulated, phase modulated, and coherent I/Q link have been used to compare performance of the different architectures in terms of linearity and SFDR.

  3. A 220 GHz Communications Link Utilizing Frequency Multipliers

    DTIC Science & Technology

    2016-03-17

    Laboratory, 2800 Powder Mill Rd., Adelphi, MD 20783 2Army Research Office, 4300 S Miami Blvd, Durham, NC 27703 Abstract: A solid - state 220-GHz...mixers) is limited, and one is left with passive components. As a result, the attainable solid - state output power available at this frequency range is...applications in 0.13μm SiGe BiCMOS,” 2014 IEEE International Solid - State Circuits Conference Digest of Technical Papers (ISSCC), pp. 256 – 257, San

  4. High-Frequency Transformation of Undeveloped Plastids in Tobacco Suspension Cells

    PubMed Central

    Langbecker, Camri L.; Ye, Guang-Ning; Broyles, Debra L.; Duggan, Lisa L.; Xu, Charles W.; Hajdukiewicz, Peter T.J.; Armstrong, Charles L.; Staub, Jeffrey M.

    2004-01-01

    Although leaf chloroplast transformation technology was developed more than a decade ago, no reports exist of stable transformation of undeveloped plastids or other specialized plastid types, such as proplastids, etioplasts, or amyloplasts. In this work we report development of a dark-grown tobacco suspension cell model system to investigate the transformation potential of undeveloped plastids. Electron microscope analysis confirmed that the suspension cells carry plastids that are significantly smaller (approximately 50-fold less in volume) and have a very different subcellular localization and developmental state than leaf cell chloroplasts. Using antibiotic selection in the light, we demonstrated that both plastid and nuclear transformation of these cell suspensions is efficient and reproducible, with plastid transformation frequency at least equal to that of leaf chloroplast transformation. Homoplasmic plastid transformants are readily obtained in cell colonies, or in regenerated plants, providing a more consistent and versatile model than the leaf transformation system. Because of the uniformity of the cell suspension model, we could further show that growth rate, selection scheme, particle size, and DNA amount influence the frequency of transformation. Our results indicate that the rate-limiting steps for nuclear and plastid transformation are different, and each must be optimized separately. The suspension cell system will be useful as a model for understanding transformation in those plant species that utilize dark-grown embryogenic cultures and for characterizing the steps that lead to homoplasmic plastid transformation. PMID:15141065

  5. Effect of coherence and polarization on frequency resolution in optical Fourier transforming system.

    PubMed

    Ostrovsky, Andrey S; Olvera-Santamaría, Miguel Á; Romero-Soría, Paulo C

    2011-12-01

    Using an example of vector Gaussian Schell-model beam, we demonstrate and analyze the dependence of the spatial frequency resolution in optical Fourier transforming system on the intrinsic coherence-polarization structure of illumination.

  6. Temporal resolution limits of time-to-frequency transformations.

    PubMed

    Fernández-Pousa, Carlos R

    2006-10-15

    Time-to-frequency converters are devices that transfer the intensity of a light pulse to its spectrum. The two architectures of these converters are studied: a dispersive line followed by a phase modulator and a single time lens operating in the spectral Fraunhofer regime. These two configurations are shown not to be equivalent in general: the first one provides an incoherent time-to-frequency mapping, whereas the second depends on the degree of coherence of the pulse. In this case, the recorded spectrum is the intensity of a partially coherent residually dispersed pulse, and the spectral Fraunhofer condition is the requirement of negligible residual dispersion. Converters operated outside the spectral Fraunhofer limit can achieve a subpicosecond resolution with moderate time-lens phase factors. Their use for pulse characterization is briefly analyzed.

  7. Evaluation of a Multi-kw, High Frequency Transformer for Space Applications

    NASA Technical Reports Server (NTRS)

    Roth, Mary Ellen

    1994-01-01

    Various NASA studies have shown that high power (multi-kW and higher) electrical systems for various aerospace applications favor high frequency distribution systems, due to the improved safety and weight factors associated with those systems. Other favorable characteristics include low EMI, minimal wiring and ease of system parameter sensing and control of a single phase system. In aerospace power systems, as in terrestrial AC distribution systems, transformers are needed to provide voltage changes, isolation and the resetting of ground. Under NASA contract NAS3-21948 a multi-kW high frequency transformer was designed, fabricated and tested by Thermal Technology Lab, Inc. of Buffalo, New York. 'The goals of this program included the determination of the relationships between transformer weight, efficiency and operating frequency; low internal temperatures and reduced specific weight; and the validation of these new design concepts through experimentation and the fabrication and testing of transformers and their insulation systems.' The transformer was delivered to NASA-Lewis, where an evaluation program was conducted in Lewis' High Power High Frequency Component Test Facility. The transformer was tested in both atmosphere and under vacuum conditions. This paper will discuss the design of the transformer, the evaluation program and test results, the failures experienced and conclusions.

  8. Quantum Image Encryption Based on Iterative Framework of Frequency-Spatial Domain Transforms

    NASA Astrophysics Data System (ADS)

    Wang, Han; Wang, Jian; Geng, Ya-Cong; Song, Yan; Liu, Ji-Qiang

    2017-07-01

    A novel quantum image encryption and decryption algorithm based on iteration framework of frequency-spatial domain transforms is proposed. In this paper, the images are represented in the flexible representation for quantum images (FRQI). Previous quantum image encryption algorithms are realized by spatial domain transform to scramble the position information of original images and frequency domain transform to encode the color information of images. But there are some problems such as the periodicity of spatial domain transform, which will make it easy to recover the original images. Hence, we present the iterative framework of frequency-spatial domain transforms. Based on the iterative framework, the novel encryption algorithm uses Fibonacci transform and geometric transform for many times to scramble the position information of the original images and double random-phase encoding to encode the color information of the images. The encryption keys include the iterative time t of the Fibonacci transform, the iterative time l of the geometric transform, the geometric transform matrix G i which is n × n matrix, the classical binary sequences K ( k0k1{\\ldots } k_{2^{2n}-1}) and D(d0d1{\\ldots } d_{2^{2n}-1}). Here the key space of Fibonacci transform and geometric transform are both estimated to be 226. The key space of binary sequences is (2 n×n ) × (2 n×n ). Then the key space of the entire algorithm is about 2^{2{n2}+52}. Since all quantum operations are invertible, the quantum image decryption algorithm is the inverse of the encryption algorithm. The results of numerical simulation and analysis indicate that the proposed algorithm has high security and high sensitivity.

  9. Quantum Image Encryption Based on Iterative Framework of Frequency-Spatial Domain Transforms

    NASA Astrophysics Data System (ADS)

    Wang, Han; Wang, Jian; Geng, Ya-Cong; Song, Yan; Liu, Ji-Qiang

    2017-10-01

    A novel quantum image encryption and decryption algorithm based on iteration framework of frequency-spatial domain transforms is proposed. In this paper, the images are represented in the flexible representation for quantum images (FRQI). Previous quantum image encryption algorithms are realized by spatial domain transform to scramble the position information of original images and frequency domain transform to encode the color information of images. But there are some problems such as the periodicity of spatial domain transform, which will make it easy to recover the original images. Hence, we present the iterative framework of frequency-spatial domain transforms. Based on the iterative framework, the novel encryption algorithm uses Fibonacci transform and geometric transform for many times to scramble the position information of the original images and double random-phase encoding to encode the color information of the images. The encryption keys include the iterative time t of the Fibonacci transform, the iterative time l of the geometric transform, the geometric transform matrix G i which is n × n matrix, the classical binary sequences K (k0k1{\\ldots } k_{2^{2n}-1}) and D(d0d1{\\ldots } d_{2^{2n}-1}). Here the key space of Fibonacci transform and geometric transform are both estimated to be 226. The key space of binary sequences is (2 n× n ) × (2 n× n ). Then the key space of the entire algorithm is about 2^{2{n2}+52}. Since all quantum operations are invertible, the quantum image decryption algorithm is the inverse of the encryption algorithm. The results of numerical simulation and analysis indicate that the proposed algorithm has high security and high sensitivity.

  10. A novel feature link quality analysis method applied in satellite adaptive frequency hopping communication

    NASA Astrophysics Data System (ADS)

    Wu, Dan; Wang, Bing; Han, Zhixue; Xiao, Changchun

    2009-12-01

    A novel feature link quality analysis method (FLQAM) applied in satellite adaptive frequency hopping communication is presented in this paper. The method uses a frequency domain feature to tell whether the tested frequency area is jammed or not, which is much simple and efficient compared with traditional methods. Simulations are performed in Matlab environment and show that the success detecting rates is above 95% when INR is over -1dB.

  11. Compact high voltage, high peak power, high frequency transformer for converter type modulator applications.

    PubMed

    Reghu, T; Mandloi, V; Shrivastava, Purushottam

    2016-04-01

    The design and development of a compact high voltage, high peak power, high frequency transformer for a converter type modulator of klystron amplifiers is presented. The transformer has been designed to operate at a frequency of 20 kHz and at a flux swing of ±0.6 T. Iron (Fe) based nanocrystalline material has been selected as a core for the construction of the transformer. The transformer employs a specially designed solid Teflon bobbin having 120 kV insulation for winding the high voltage secondary windings. The flux swing of the core has been experimentally found by plotting the hysteresis loop at actual operating conditions. Based on the design, a prototype transformer has been built which is per se a unique combination of high voltage, high frequency, and peak power specifications. The transformer was able to provide 58 kV (pk-pk) at the secondary with a peak power handling capability of 700 kVA. The transformation ratio was 1:17. The performance of the transformer is also presented and discussed.

  12. Compact high voltage, high peak power, high frequency transformer for converter type modulator applications

    NASA Astrophysics Data System (ADS)

    Reghu, T.; Mandloi, V.; Shrivastava, Purushottam

    2016-04-01

    The design and development of a compact high voltage, high peak power, high frequency transformer for a converter type modulator of klystron amplifiers is presented. The transformer has been designed to operate at a frequency of 20 kHz and at a flux swing of ±0.6 T. Iron (Fe) based nanocrystalline material has been selected as a core for the construction of the transformer. The transformer employs a specially designed solid Teflon bobbin having 120 kV insulation for winding the high voltage secondary windings. The flux swing of the core has been experimentally found by plotting the hysteresis loop at actual operating conditions. Based on the design, a prototype transformer has been built which is per se a unique combination of high voltage, high frequency, and peak power specifications. The transformer was able to provide 58 kV (pk-pk) at the secondary with a peak power handling capability of 700 kVA. The transformation ratio was 1:17. The performance of the transformer is also presented and discussed.

  13. Precise and fast spatial-frequency analysis using the iterative local Fourier transform.

    PubMed

    Lee, Sukmock; Choi, Heejoo; Kim, Dae Wook

    2016-09-19

    The use of the discrete Fourier transform has decreased since the introduction of the fast Fourier transform (fFT), which is a numerically efficient computing process. This paper presents the iterative local Fourier transform (ilFT), a set of new processing algorithms that iteratively apply the discrete Fourier transform within a local and optimal frequency domain. The new technique achieves 210 times higher frequency resolution than the fFT within a comparable computation time. The method's superb computing efficiency, high resolution, spectrum zoom-in capability, and overall performance are evaluated and compared to other advanced high-resolution Fourier transform techniques, such as the fFT combined with several fitting methods. The effectiveness of the ilFT is demonstrated through the data analysis of a set of Talbot self-images (1280 × 1024 pixels) obtained with an experimental setup using grating in a diverging beam produced by a coherent point source.

  14. Performance comparison of ISAR imaging method based on time frequency transforms

    NASA Astrophysics Data System (ADS)

    Xie, Chunjian; Guo, Chenjiang; Xu, Jiadong

    2013-03-01

    Inverse synthetic aperture radar (ISAR) can image the moving target, especially the target in the air, so it is important in the air defence and missile defence system. Time-frequency Transform was applied to ISAR imaging process widely. Several time frequency transforms were introduced. Noise jamming methods were analysed, and when these noise jamming were added to the echo of the ISAR receiver, the image can become blur even can't to be identify. But the effect is different to the different time frequency analysis. The results of simulation experiment show the Performance Comparison of the method.

  15. A frequency measurement algorithm for non-stationary signals by using wavelet transform

    NASA Astrophysics Data System (ADS)

    Seo, Seong-Heon; Oh, Dong Keun

    2016-11-01

    Scalogram is widely used to measure instantaneous frequencies of non-stationary signals. However, the basic property of the scalogram is observed only for stationary sinusoidal functions. A property of the scalogram for non-stationary signal is analytically derived in this paper. Based on the property, a new frequency measurement algorithm is proposed. In addition, a filter that can separate two similar frequency signals is developed based on the wavelet transform.

  16. Embodied mental rotation: a special link between egocentric transformation and the bodily self

    PubMed Central

    Kaltner, Sandra; Riecke, Bernhard E.; Jansen, Petra

    2014-01-01

    This experiment investigated the influence of motor expertise on object-based versus egocentric transformations in a chronometric mental rotation task using images of either the own or another person’s body as stimulus material. According to the embodied cognition viewpoint, we hypothesized motor-experts to outperform non-motor experts specifically in the egocentric condition because of higher kinesthetic representation and motor simulations compared to object-based transformations. In line with this, we expected that images of the own body are solved faster than another person’s body stimuli. Results showed a benefit of motor expertise and representations of another person’s body, but only for the object-based transformation task. That is, this other-advantage diminishes in egocentric transformations. Since motor experts did not show any specific expertise in rotational movements, we concluded that using human bodies as stimulus material elicits embodied spatial transformations, which facilitates performance exclusively for egocentric transformations. Regarding stimulus material, the other-advantage ascribed to increased self-awareness-consciousness distracting attention-demanding resources, disappeared in the egocentric condition. This result may be due to the stronger link between the bodily self and motor representations compared to that emerging in object-based transformations. PMID:24917832

  17. Hydrocarbon Reservoir Prediction Using Bi-Gaussian S Transform Based Time-Frequency Analysis Approach

    NASA Astrophysics Data System (ADS)

    Cheng, Z.; Chen, Y.; Liu, Y.; Liu, W.; Zhang, G.

    2015-12-01

    Among those hydrocarbon reservoir detection techniques, the time-frequency analysis based approach is one of the most widely used approaches because of its straightforward indication of low-frequency anomalies from the time-frequency maps, that is to say, the low-frequency bright spots usually indicate the potential hydrocarbon reservoirs. The time-frequency analysis based approach is easy to implement, and more importantly, is usually of high fidelity in reservoir prediction, compared with the state-of-the-art approaches, and thus is of great interest to petroleum geologists, geophysicists, and reservoir engineers. The S transform has been frequently used in obtaining the time-frequency maps because of its better performance in controlling the compromise between the time and frequency resolutions than the alternatives, such as the short-time Fourier transform, Gabor transform, and continuous wavelet transform. The window function used in the majority of previous S transform applications is the symmetric Gaussian window. However, one problem with the symmetric Gaussian window is the degradation of time resolution in the time-frequency map due to the long front taper. In our study, a bi-Gaussian S transform that substitutes the symmetric Gaussian window with an asymmetry bi-Gaussian window is proposed to analyze the multi-channel seismic data in order to predict hydrocarbon reservoirs. The bi-Gaussian window introduces asymmetry in the resultant time-frequency spectrum, with time resolution better in the front direction, as compared with the back direction. It is the first time that the bi-Gaussian S transform is used for analyzing multi-channel post-stack seismic data in order to predict hydrocarbon reservoirs since its invention in 2003. The superiority of the bi-Gaussian S transform over traditional S transform is tested on a real land seismic data example. The performance shows that the enhanced temporal resolution can help us depict more clearly the edge of the

  18. Time-frequency analysis of spike-wave discharges using a modified wavelet transform.

    PubMed

    Bosnyakova, Daria; Gabova, Alexandra; Kuznetsova, Galina; Obukhov, Yuri; Midzyanovskaya, Inna; Salonin, Dmitrij; van Rijn, Clementina; Coenen, Anton; Tuomisto, Leene; van Luijtelaar, Gilles

    2006-06-30

    The continuous Morlet wavelet transform was used for the analysis of the time-frequency pattern of spike-wave discharges (SWD) as can be recorded in a genetic animal model of absence epilepsy (rats of the WAG/Rij strain). We developed a new wavelet transform that allows to obtain the time-frequency dynamics of the dominating rhythm during the discharges. SWD were analyzed pre- and post-administration of certain drugs. SWD recorded predrug demonstrate quite uniform time-frequency dynamics of the dominant rhythm. The beginning of the discharge has a short period with the highest frequency value (up to 15 Hz). Then the frequency decreases to 7-9 Hz and frequency modulation occurs during the discharge in this range with a period of 0.5-0.7 s. Specific changes of SWD time-frequency dynamics were found after the administration of psychoactive drugs, addressing different brain mediator and modulator systems. Short multiple SWDs appeared under low (0.5 mg/kg) doses of haloperidol, they are characterized by a fast frequency decrease to 5-6 Hz at the end of every discharge. The frequency of the dominant frequency of SWD was not stable in long lasting SWD after 1.0 mg/kg or more haloperidol: then two periodicities were found. Long lasting SWD seen after the administration of vigabatrin showed a stable frequency of the discharge. The EEG after Ketamin showed a distinct 5 s quasiperiodicity. No clear changes of time-frequency dynamics of SWD were found after perilamine. It can be concluded that the use of the modified Morlet wavelet transform allows to describe significant parameters of the dynamics in the time-frequency domain of the dominant rhythm of SWD that were not previously detected.

  19. Experimental and theoretical study of a low-frequency inductive discharge of the transformer type

    NASA Astrophysics Data System (ADS)

    Isupov, M. V.; Fedoseev, A. V.; Sukhinin, G. I.; Ulanov, I. M.

    2014-12-01

    The electrophysical and thermophysical characteristics of a low-frequency inductive discharge of the transformer type were studied in argon within a wide range of discharge parameters: densities of discharge current from 0.1 to 0.8 A/cm2 and argon pressures from 15 to 6000 Pa. A simplified model of the low-frequency inductive discharge of the transformer type, based on simultaneous solution to the balance equations for electrons and metastable atoms at the axis of the gas-discharge tube and balance equations for gas temperature and electron energy, was developed. Dependence of electric field strength of the low-frequency inductive discharge of the transformer type on argon pressure and discharge current was calculated. It is shown that calculation results agree with the measurement data and describe their main features: descending voltage-current characteristic of discharge and local minimum in pressure dependence of electric field strength.

  20. Enhanced link availability for free space optical time-frequency transfer using adaptive optic terminals

    NASA Astrophysics Data System (ADS)

    Petrillo, Keith G.; Dennis, Michael L.; Juarez, Juan C.; Souza, Katherine T.; Baumann, Esther; Bergeron, Hugo; Coddington, Ian; Deschenes, Jean-Daniel; Giorgetta, Fabrizio R.; Newbury, Nathan R.; Sinclair, Laura C.; Swann, William C.

    2016-05-01

    Optical time and frequency transfer offers extremely high precision wireless synchronization across multiple platforms for untethered distributed systems. While large apertures provide antenna gain for wireless systems which leads to robust link budgets and operation over increased distance, turbulence disrupts the beam and limits the full realization of the antenna gain. Adaptive optics can correct for phase distortions due to turbulence which potentially increases the total gain of the aperture to that for diffraction-limited operation. Here, we explore the use of adaptive optics terminals for free-space time and frequency transfer. We find that the requirement of reciprocity in a two-way time and frequency transfer link is maintained during the phase compensation of adaptive optics, and that the enhanced link budget due to aperture gain allows for potential system operation over ranges of at least tens of kilometers.

  1. Equivalent circuit of radio frequency-plasma with the transformer model.

    PubMed

    Nishida, K; Mochizuki, S; Ohta, M; Yasumoto, M; Lettry, J; Mattei, S; Hatayama, A

    2014-02-01

    LINAC4 H(-) source is radio frequency (RF) driven type source. In the RF system, it is required to match the load impedance, which includes H(-) source, to that of final amplifier. We model RF plasma inside the H(-) source as circuit elements using transformer model so that characteristics of the load impedance become calculable. It has been shown that the modeling based on the transformer model works well to predict the resistance and inductance of the plasma.

  2. Simultaneous transfer of optical frequency and time over 306 km long-haul optical fibre link

    NASA Astrophysics Data System (ADS)

    Hucl, Vaclav; Cizek, Martin; Pravdova, Lenka; Rerucha, Simon; Hrabina, Jan; Mikel, Bretislav; Smotlacha, Vladimir; Vojtech, Josef; Lazar, Josef; Cip, Ondrej

    2016-12-01

    Optical fibre links for distributing optical frequencies and time stamps were researched and experimentally tested in the past fifteen years. They have been used mainly for stability comparison of experimental optical clocks. But recent development puts demands on a technology transfer from laboratory experiments to the real industry. The remote calibration of interrogators of Fibre Bragg Grating strain sensory networks is one of important examples. The first step of the adoption the time and frequency broadcasting should be the drop-out free long-term operation of this technology between research laboratories connected via long-haul fibre links. We present a 306 km long-haul optical fibre link between the cities of Prague and Brno in the Czech Republic where a coherent transfer of stable optical frequency and a stable time signal has been firstly demonstrated. The link between ISI CAS Brno and CESNET Prague uses an internet communication fibre where a window of 1540-1546 nm is dedicated for the coherent transfer and 1PPS signal. The link is equipped with 6 bidirectional EDFA amplifiers. The optical frequency standard based on the highly-coherent laser Koheras Adjustik working at 1540.5 nm and stabilized with a saturation absorption spectroscopy technique was used for the coherent wave transfer. The suppression of the Doppler shift induced by the optical fibre was based on an accoustooptical modulator with a servo-loop including a fast PID controller processing the beat-note frequency given by mixing of the Adjustik laser (Brno) and the reflected frequency of this laser from the far end of 306 km long-haul fibre link (Prague). We verified the Doppler shift suppression for the coherent wave with a measuring method analysing the transport delay of the 1PPS signal.

  3. Power conversion distribution system using a resonant high-frequency AC link

    NASA Technical Reports Server (NTRS)

    Sood, P. K.; Lipo, T. A.

    1986-01-01

    Static power conversion systems based on a resonant high frequency (HF) link offers a significant reduction in the size and weight of the equipment over that achieved with conventional approaches, especially when multiple sources and loads are to be integrated. A faster system response and absence of audible noise are the other principal characteristics of such systems. A conversion configuration based on a HF link which is suitable for applications requiring distributed power is proposed.

  4. First international comparison of fountain primary frequency standards via a long distance optical fiber link

    NASA Astrophysics Data System (ADS)

    Guéna, J.; Weyers, S.; Abgrall, M.; Grebing, C.; Gerginov, V.; Rosenbusch, P.; Bize, S.; Lipphardt, B.; Denker, H.; Quintin, N.; Raupach, S. M. F.; Nicolodi, D.; Stefani, F.; Chiodo, N.; Koke, S.; Kuhl, A.; Wiotte, F.; Meynadier, F.; Camisard, E.; Chardonnet, C.; Le Coq, Y.; Lours, M.; Santarelli, G.; Amy-Klein, A.; Le Targat, R.; Lopez, O.; Pottie, P. E.; Grosche, G.

    2017-06-01

    We report on the first comparison of distant caesium fountain primary frequency standards (PFSs) via an optical fiber link. The 1415 km long optical link connects two PFSs at LNE-SYRTE (Laboratoire National de métrologie et d’Essais—SYstème de Références Temps-Espace) in Paris (France) with two at PTB (Physikalisch-Technische Bundesanstalt) in Braunschweig (Germany). For a long time, these PFSs have been major contributors to accuracy of the International Atomic Time (TAI), with stated accuracies of around 3× {{10}-16} . They have also been the references for a number of absolute measurements of clock transition frequencies in various optical frequency standards in view of a future redefinition of the second. The phase coherent optical frequency transfer via a stabilized telecom fiber link enables far better resolution than any other means of frequency transfer based on satellite links. The agreement for each pair of distant fountains compared is well within the combined uncertainty of a few 10-16 for all the comparisons, which fully supports the stated PFSs’ uncertainties. The comparison also includes a rubidium fountain frequency standard participating in the steering of TAI and enables a new absolute determination of the 87Rb ground state hyperfine transition frequency with an uncertainty of 3.1× {{10}-16} . This paper is dedicated to the memory of André Clairon, who passed away on 24 December 2015, for his pioneering and long-lasting efforts in atomic fountains. He also pioneered optical links from as early as 1997.

  5. Linking EEG signals, brain functions and mental operations: Advantages of the Laplacian transformation.

    PubMed

    Vidal, Franck; Burle, Boris; Spieser, Laure; Carbonnell, Laurence; Meckler, Cédric; Casini, Laurence; Hasbroucq, Thierry

    2015-09-01

    Electroencephalography (EEG) is a very popular technique for investigating brain functions and/or mental processes. To this aim, EEG activities must be interpreted in terms of brain and/or mental processes. EEG signals being a direct manifestation of neuronal activity it is often assumed that such interpretations are quite obvious or, at least, straightforward. However, they often rely on (explicit or even implicit) assumptions regarding the structures supposed to generate the EEG activities of interest. For these assumptions to be used appropriately, reliable links between EEG activities and the underlying brain structures must be established. Because of volume conduction effects and the mixture of activities they induce, these links are difficult to establish with scalp potential recordings. We present different examples showing how the Laplacian transformation, acting as an efficient source separation method, allowed to establish more reliable links between EEG activities and brain generators and, ultimately, with mental operations. The nature of those links depends on the depth of inferences that can vary from weak to strong. Along this continuum, we show that 1) while the effects of experimental manipulation can appear widely distributed with scalp potentials, Laplacian transformation allows to reveal several generators contributing (in different manners) to these modulations, 2) amplitude variations within the same set of generators can generate spurious differences in scalp potential topographies, often interpreted as reflecting different source configurations. In such a case, Laplacian transformation provides much more similar topographies, evidencing the same generator(s) set, and 3) using the LRP as an index of response activation most often produces ambiguous results, Laplacian-transformed response-locked ERPs obtained over motor areas allow resolving these ambiguities.

  6. Double Langmuir frequency radiation due to transformation processes in turbulent plasma

    NASA Astrophysics Data System (ADS)

    Pavlenko, V. N.; Panchenko, V. G.; Beloshenko, N. A.

    2015-04-01

    We investigate the transformation process of longitudinal Langmuir wave into the transverse electromagnetic wave in turbulent plasma subjected to an upper hybrid pump. The case, when upper hybrid pump wave decays into daughter and ion - sound waves is considered. The transformation of the Langmuir wave into electromagnetic one is considered as the possible mechanism of energy radiation from the plasma. It is shown that the frequency of such radiation is chosen to be near double electron Langmuir frequency 2ωpe . These results give us the possibility to explain the nature of radiation from the laboratory and cosmic plasmas (particularly, from the solar crown).

  7. A 920-kilometer optical fiber link for frequency metrology at the 19th decimal place.

    PubMed

    Predehl, K; Grosche, G; Raupach, S M F; Droste, S; Terra, O; Alnis, J; Legero, Th; Hänsch, T W; Udem, Th; Holzwarth, R; Schnatz, H

    2012-04-27

    Optical clocks show unprecedented accuracy, surpassing that of previously available clock systems by more than one order of magnitude. Precise intercomparisons will enable a variety of experiments, including tests of fundamental quantum physics and cosmology and applications in geodesy and navigation. Well-established, satellite-based techniques for microwave dissemination are not adequate to compare optical clocks. Here, we present phase-stabilized distribution of an optical frequency over 920 kilometers of telecommunication fiber. We used two antiparallel fiber links to determine their fractional frequency instability (modified Allan deviation) to 5 × 10(-15) in a 1-second integration time, reaching 10(-18) in less than 1000 seconds. For long integration times τ, the deviation from the expected frequency value has been constrained to within 4 × 10(-19). The link may serve as part of a Europe-wide optical frequency dissemination network.

  8. A link between c-Myc-mediated transcriptional repression and neoplastic transformation.

    PubMed Central

    Lee, L A; Dolde, C; Barrett, J; Wu, C S; Dang, C V

    1996-01-01

    Recent studies indicate that the transcription factor c-Myc contributes to oncogenesis by altering the expression of genes involved in cell proliferation, but its precise function in neoplasia remains ambiguous. The ability of c-Myc to bind the sequence CAC(G/A)TG and transactivate appears to be linked to its transforming activity; however, c-Myc also represses transcription in vitro through a pyrimidine-rich cis element termed the initiator (Inr). In transfection experiments using the adenoviral major late (adML) promoter, which contains two Myc binding sites and an Inr, we determined that c-Myc represses transcription through the initiator in vivo. This activity requires the dimerization domain and amino acids 106 to 143, which are located within the transactivation domain and are necessary for neoplastic transformation. We studied a lymphoma-derived c-Myc substitution mutation at 115-Phe, which is within the region required for transcriptional suppression, and found the mutant more effective than wild-type c-Myc in transforming rodent fibroblasts and in suppressing the adML promoter. Our studies of both loss-of-function and gain-of-function c-Myc mutations suggest a link between c-Myc-mediated neoplastic transformation and transcriptional repression through the Inr. PMID:8601634

  9. A link between c-Myc-mediated transcriptional repression and neoplastic transformation.

    PubMed

    Lee, L A; Dolde, C; Barrett, J; Wu, C S; Dang, C V

    1996-04-01

    Recent studies indicate that the transcription factor c-Myc contributes to oncogenesis by altering the expression of genes involved in cell proliferation, but its precise function in neoplasia remains ambiguous. The ability of c-Myc to bind the sequence CAC(G/A)TG and transactivate appears to be linked to its transforming activity; however, c-Myc also represses transcription in vitro through a pyrimidine-rich cis element termed the initiator (Inr). In transfection experiments using the adenoviral major late (adML) promoter, which contains two Myc binding sites and an Inr, we determined that c-Myc represses transcription through the initiator in vivo. This activity requires the dimerization domain and amino acids 106 to 143, which are located within the transactivation domain and are necessary for neoplastic transformation. We studied a lymphoma-derived c-Myc substitution mutation at 115-Phe, which is within the region required for transcriptional suppression, and found the mutant more effective than wild-type c-Myc in transforming rodent fibroblasts and in suppressing the adML promoter. Our studies of both loss-of-function and gain-of-function c-Myc mutations suggest a link between c-Myc-mediated neoplastic transformation and transcriptional repression through the Inr.

  10. Frequency hopping signal detection based on wavelet decomposition and Hilbert-Huang transform

    NASA Astrophysics Data System (ADS)

    Zheng, Yang; Chen, Xihao; Zhu, Rui

    2017-07-01

    Frequency hopping (FH) signal is widely adopted by military communications as a kind of low probability interception signal. Therefore, it is very important to research the FH signal detection algorithm. The existing detection algorithm of FH signals based on the time-frequency analysis cannot satisfy the time and frequency resolution requirement at the same time due to the influence of window function. In order to solve this problem, an algorithm based on wavelet decomposition and Hilbert-Huang transform (HHT) was proposed. The proposed algorithm removes the noise of the received signals by wavelet decomposition and detects the FH signals by Hilbert-Huang transform. Simulation results show the proposed algorithm takes into account both the time resolution and the frequency resolution. Correspondingly, the accuracy of FH signals detection can be improved.

  11. A new principle technic for the transformation from frequency domain to time domain

    NASA Astrophysics Data System (ADS)

    Gao, Ben-Qing

    2017-03-01

    A principle technic for the transformation from frequency domain to time domain is presented. Firstly, a special type of frequency domain transcendental equation is obtained for an expected frequency domain parameter which is a rational or irrational fraction expression. Secondly, the inverse Laplace transformation is performed. When the two time-domain factors corresponding to the two frequency domain factors at two sides of frequency domain transcendental equation are known quantities, a time domain transcendental equation is reached. At last, the expected time domain parameter corresponding to the expected frequency domain parameter can be solved by the inverse convolution process. Proceeding from rational or irrational fraction expression, all solving process is provided. In the meantime, the property of time domain sequence is analyzed and the strategy for choosing the parameter values is described. Numerical examples are presented to verify the proposed theory and technic. Except for rational or irrational fraction expressions, examples of complex relative permittivity of water and plasma are used as verification method. The principle method proposed in the paper can easily solve problems which are difficult to be solved by Laplace transformation.

  12. Direct link of a mid-infrared QCL to a frequency comb by optical injection.

    PubMed

    Borri, S; Galli, I; Cappelli, F; Bismuto, A; Bartalini, S; Cancio, P; Giusfredi, G; Mazzotti, D; Faist, J; De Natale, P

    2012-03-15

    A narrow-linewidth comb-linked nonlinear source is used as master radiation to injection lock a room-temperature mid-infrared quantum cascade laser (QCL). This process leads to a direct lock of the QCL to the optical frequency comb, providing the unique features of narrow linewidth, absolute frequency, higher output power, and wide mode-hop-free tunability. The QCL reproduces the injected radiation within more than 94%, with a reduction of the frequency-noise spectral density by 3 to 4 orders of magnitude up to about 100 kHz, and a linewidth narrowing from a few MHz to 20 kHz.

  13. Extracting Micro-Doppler Radar Signatures from Rotating Targets Using Fourier-Bessel Transform and Time-Frequency Analysis

    DTIC Science & Technology

    2014-10-16

    1 Extracting micro-Doppler radar signatures from rotating targets using Fourier- Bessel Transform and Time-Frequency analysis P. Suresh1,T...kvenkataramanaiah@sssihl.edu.in Abstract In this paper, we report the efficiency of Fourier Bessel transform and time-frequency based method in conjunction with...decomposed into stationary and non-stationary components using Fourier Bessel transform in conjunction with the fractional Fourier transform. The

  14. Frequency noise induced by fiber perturbations in a fiber-linked stabilized laser

    NASA Technical Reports Server (NTRS)

    Pang, YI; Hamilton, Jeffrey J.; Richard, Jean-Paul

    1992-01-01

    The effects of acoustic perturbations on an optical fiber that links a stabilized laser to its reference cavity are studied. An extrapolation indicates that 69 dB of acoustic noise impinging on a 1-m segment of the 10-m fiber contribute frequency noise at the level of 1 Hz/(Hz)1/2 in the 1100-2100-Hz band.

  15. Frequency-Modulated Microwave Photonic Links with Direct Detection: Review and Theory

    DTIC Science & Technology

    2010-12-15

    splitters was suggested by [13]. In this case, balanced photodetection was used to cancel AM. Such an interferometer was experimentally veried by [14...residual intensity modulation as well as imperfect common- mode rejection from the balanced photodetection . 3.2 Filter coecients The frequency...Numerical model of an FM photonic link with two discriminator lters and balanced detection . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.2.1

  16. The Quality and Frequency of Mother-Toddler Conflict: Links with Attachment and Temperament

    ERIC Educational Resources Information Center

    Laible, Deborah; Panfile, Tia; Makariev, Drika

    2008-01-01

    The goal of this study was to examine the links among attachment, child temperament, and the quality and frequency of mother-toddler conflict. Sixty-four mothers and children took part in a series of laboratory tasks when the child was 30 months of age and an audio-recorded home observation when the child was 36 months of age. All episodes of…

  17. More Use Almost Always Means a Smaller Frequency Effect: Aging, Bilingualism, and the Weaker Links Hypothesis

    ERIC Educational Resources Information Center

    Gollan, Tamar H.; Montoya, Rosa I.; Cera, Cynthia; Sandoval, Tiffany C.

    2008-01-01

    The "weaker links" hypothesis proposes that bilinguals are disadvantaged relative to monolinguals on speaking tasks because they divide frequency-of-use between two languages. To test this proposal, we contrasted the effects of increased word use associated with monolingualism, language dominance, and increased age on picture naming times. In two…

  18. Frequency division multiplexed microwave and baseband digital optical fiber link for phased array antennas

    NASA Astrophysics Data System (ADS)

    Heim, Peter J.; McClay, C. Phillip

    1990-05-01

    A frequency-division multiplexed optical fiber link is described in which microwave (1-8 GHz) and baseband digital (1-10 Mb/s) signals are combined electrically and transmitted through a direct-modulation microwave optical link. The microwave signal does not affect bit error rate (BER) performance of the Manchester-coded baseband digital data link. The baseband digital signal affects microwave signal quality by generating second-order intermodulation noise. The intermodulation noise power density is found to be proportional to both the microwave input power and the digital input power, enabling the system to be modeled as a mixer (AM modulator). The conversion loss for the digital signal is approximately 68 dB for a 1-GHz microwave signal and is highly dependent on the microwave frequency, reaching a minimum value of 41 dB at 4.5 GHz, corresponding to the laser diode relaxation oscillation frequency. It is shown that Manchester coding on the digital link places the intermodulation noise peak away from the microwave signal, preventing degradation of close-carrier phase noise (<1 kHz offset). A direct trade-off between intermodulation noise and digital link margin is developed to project system performance.

  19. Transformation frequency of a mariner-based transposon in Rickettsia rickettsii.

    PubMed

    Clark, Tina R; Lackey, Amanda M; Kleba, Betsy; Driskell, Lonnie O; Lutter, Erika I; Martens, Craig; Wood, David O; Hackstadt, Ted

    2011-09-01

    Transformation frequencies of a mariner-based transposon system in Rickettsia rickettsii were determined using a plaque assay system for enumeration and isolation of mutants. Sequence analysis of insertion sites in both R. rickettsii and R. prowazekii indicated that insertions were random. Transposon mutagenesis provides a useful tool for rickettsial research.

  20. Time-Frequency Transform Techniques Applied to Ultra-wideband Ground-Penetrating Radar

    NASA Astrophysics Data System (ADS)

    Yedlin, M.; Cresp, A.; Dauviganc, J. Y.; Gaffet, S.; Sénéchal, G.; Fortino, N.; Pichot, C.; Aliferis, I.

    2009-04-01

    Background Recently, Dauvignac et al [1] utilized a ground penetrating radar unit consisting of an exponentially tapered slot antenna (ETSA) of the Vivaldi type, connected to an Agilent vector network analyzer to obtain a densely-sampled profile in the anti-blast tunnel of LSBB (Low-Noise inter-Disciplinary Underground Science & Technology Laboratory) located in Rustrel, France. The frequency data, from 150 MHz to 2 GHz, was inverse Fourier-transformed to obtain the time dependent data. Simultaneously, the same profile was obtained using a RAMAC 500 MHz ground-penetrating radar unit. Initial comparison of both data sets was done in the time-domain. Data obtained from the ETSA will be inverted using a constrained least squares algorithm, in order that the depth-dependent permittivity can be inferred. As a quality control, the RAMAC data will also be inverted. The resulting permittivity profiles obtained in both inversions will be used to image water content over a depth of several meters. Proposed Research It is well-known, qualitatively in the ground penetrating radar literature that high frequencies appear at early times, but generally are attenuated at later times, essentially due to the skin effect. However, a signal-processing verification of this well-known result is needed. We propose to use the Stockwell or S transform [2] to determine the temporal location of frequencies in both of the foregoing datasets. The S transform, a short-time Fourier transform with a frequency-dependent window, will be described and applied to synthetic data. Then the application of the S transform to the RAMAC and ETSA data will be presented, after each data set has undergone the same pre-processing. The S transform is completely linear and preserves the phase of the data, which allows for easy interpretation of the operations of filtering, due to the linear inverse of the forward S transform. Thus the S transform is ideal for comparing the temporal distribution of frequency in

  1. Analysis of frequency shifting in seismic signals using Gabor-Wigner transform

    NASA Astrophysics Data System (ADS)

    Kumar, Roshan; Sumathi, P.; Kumar, Ashok

    2015-12-01

    A hybrid time-frequency method known as Gabor-Wigner transform (GWT) is introduced in this paper for examining the time-frequency patterns of earthquake damaged buildings. GWT is developed by combining the Gabor transform (GT) and Wigner-Ville distribution (WVD). GT and WVD have been used separately on synthetic and recorded earthquake data to identify frequency shifting due to earthquake damages, but GT is prone to windowing effect and WVD involves ambiguity function. Hence to obtain better clarity and to remove the cross terms (frequency interference), GT and WVD are judiciously combined and the resultant GWT used to identify frequency shifting. Synthetic seismic response of an instrumented building and real-time earthquake data recorded on the building were investigated using GWT. It is found that GWT offers good accuracy for even slow variations in frequency, good time-frequency resolution, and localized response. Presented results confirm the efficacy of GWT when compared with GT and WVD used separately. Simulation results were quantified by the Renyi entropy measures and GWT shown to be an adequate technique in identifying localized response for structural damage detection.

  2. The frequency and malignant transformation rate of oral lichen planus and leukoplakia--a retrospective study.

    PubMed

    Brzak, Bozana Loncar; Mravak-Stipetić, Marinka; Canjuga, Ivana; Baricević, Marinka; Balicević, Drinko; Sikora, Miroslav; Filipović-Zore, Irina

    2012-09-01

    The aim of this retrospective study was to determine the frequency and malignant transformation rate of oral lichen planus and leukoplakia in a large group of oral medicine patients. Study included 12 508 patients who were referred between 1998 and 2007 to the Department of Oral Medicine. The frequency of OLP was 4.30%, leukoplakia 1.11%, and combined diagnoses 0.14%. In primary biopsies dysplasia was found in 12.96% of patients with leukoplakia and not in one with OLP and combined lesions. The highest frequency of leukoplakia was found in smokers. Women were found as predominant sufferers of both diseases and their combination. During the observed period often years malignant transformation of OLP was not detected, unlike leukoplakia where it was 0.64%. The frequency of OLP and leukoplakia in our study are comparable to other similar studies. The highest frequency of malignant transformation was observed in those patients who did not respond to our invitation to regular check-up. It is therefore neccessary to perform a detailed examination of the oral cavity in these patients and to raise patients awareness of the disease and the importance of regular follow-up.

  3. A Frequency Agile, Self-Adaptive Serial Link on Xilinx FPGAs

    NASA Astrophysics Data System (ADS)

    Aloisio, A.; Giordano, R.; Izzo, V.; Perrella, S.

    2015-06-01

    In this paper, we focused on the GTX transceiver modules of Xilinx Kintex 7 field-programmable gate arrays (FPGAs), which provide high bandwidth, low jitter on the recovered clock, and an equalization system on the transmitter and the receiver. We present a frequency agile, auto-adaptive serial link. The link is able to take care of the reconfiguration of the GTX parameters in order to fully benefit from the available link bandwidth, by setting the highest line rate. It is designed around an FPGA-embedded microprocessor, which drives the programmable ports of the GTX in order to control the quality of the received data and to easily calculate the bit-error rate in each sampling point of the eye diagram. We present the self-adaptive link project, the description of the test system, and the main results.

  4. Design of Radio Frequency Link in Automatic Test System for Multimode Mobile Communication Base Station

    NASA Astrophysics Data System (ADS)

    Zhang, Weipeng

    2015-12-01

    A modularized design for the radio frequency (RF) link in automatic test system of multimode mobile communication base station is presented, considering also the characteristics of wireless communication indices and composition of signals of base stations. The test link is divided into general module, time division duplex (TDD) module, module of spurious noise filter, module of downlink intermodulation, module of uplink intermodulation and uplink block module. The composition of modules and link functions are defined, and the interfaces of the general module and the module of spurious noise filter are described. Finally, the estimated gain budget of the test link is presented. It is verified by experiments that the system is reliable and the test efficiency is improved.

  5. Phase-coherent frequency comparison of optical clocks using a telecommunication fiber link.

    PubMed

    Schnatz, Harald; Terra, Osama; Predehl, Katharina; Feldmann, Thorsten; Legero, Thomas; Lipphardt, Burghard; Sterr, Uwe; Grosche, Gesine; Holzwarth, Ronald; Hänsch, Theodor W; Udem, Thomas; Lu, Zehuang H; Wang, Li J; Ertmer, Wolfgang; Friebe, Jan; Pape, Andrè; Rasel, Ernst-M; Riedmann, Mathias; Wübbena, Temmo

    2010-01-01

    We have explored the performance of 2 "dark fibers" of a commercial telecommunication fiber link for a remote comparison of optical clocks. These fibers establish a network in Germany that will eventually link optical frequency standards at PTB with those at the Institute of Quantum Optics (IQ) at the Leibniz University of Hanover, and the Max Planck Institutes in Erlangen (MPL) and Garching (MPQ). We demonstrate for the first time that within several minutes a phase coherent comparison of clock lasers at the few 10(-15) level can also be accomplished when the lasers are more than 100 km apart. Based on the performance of the fiber link to the IQ, we estimate the expected stability for the link from PTB to MPQ via MPL that bridges a distance of approximately 900 km.

  6. Quantum Fourier Transforms and the Complexity of Link Invariants for Quantum Doubles of Finite Groups

    NASA Astrophysics Data System (ADS)

    Krovi, Hari; Russell, Alexander

    2015-03-01

    Knot and link invariants naturally arise from any braided Hopf algebra. We consider the computational complexity of the invariants arising from an elementary family of finite-dimensional Hopf algebras: quantum doubles of finite groups [denoted , for a group G]. These induce a rich family of knot invariants and, additionally, are directly related to topological quantum computation. Regarding algorithms for these invariants, we develop quantum circuits for the quantum Fourier transform over ; in general, we show that when one can uniformly and efficiently carry out the quantum Fourier transform over the centralizers Z( g) of the elements of G, one can efficiently carry out the quantum Fourier transform over . We apply these results to the symmetric groups to yield efficient circuits for the quantum Fourier transform over . With such a Fourier transform, it is straightforward to obtain additive approximation algorithms for the related link invariant. As for hardness results, first we note that in contrast to those concerning the Jones polynomial—where the images of the braid group representations are dense in the unitary group—the images of the representations arising from are finite. This important difference appears to be directly reflected in the complexity of these invariants. While additively approximating "dense" invariants is -complete and multiplicatively approximating them is -complete, we show that certain invariants (such as invariants) are -hard to additively approximate, -hard to multiplicatively approximate, and -hard to exactly evaluate. To show this, we prove that, for groups (such as A n ) which satisfy certain properties, the probability of success of any randomized computation can be approximated to within any by the plat closure. Finally, we make partial progress on the question of simulating anyonic computation in groups uniformly as a function of the group size. In this direction, we provide efficient quantum circuits for the Clebsch

  7. Extremely low frequency magnetic field measurements in buildings with transformer stations in Switzerland.

    PubMed

    Röösli, Martin; Jenni, Daniela; Kheifets, Leeka; Mezei, Gabor

    2011-08-15

    The aim of this study was to evaluate an exposure assessment method that classifies apartments in three exposure categories of extremely low frequency magnetic fields (ELF-MF) based on the location of the apartment relative to the transformer room. We completed measurements in 39 apartments in 18 buildings. In each room of the apartments ELF-MF was concurrently measured with 5 to 6 EMDEX II meters for 10 min. Measured arithmetic mean ELF-MF was 0.59 μT in 8 apartments that were fully adjacent to a transformer room, either directly above the transformer or touching the transformer room wall-to-wall. In apartments that only partly touched the transformer room at corners or edges, average ELF-MF level was 0.14 μT. Average exposure in the remaining apartments was 0.10 μT. Kappa coefficient for exposure classification was 0.64 (95%-CI: 0.45-0.82) if only fully adjacent apartments were considered as highly exposed (>0.4 μT). We found a distinct ELF-MF exposure gradient in buildings with transformer. Exposure classification based on the location of the apartment relative to the transformer room appears feasible. Such an approach considerably reduces effort for exposure assessment and may be used to eliminate selection bias in future epidemiologic studies. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Transformative learning and research utilization in nursing practice: a missing link?

    PubMed

    Matthew-Maich, Nancy; Ploeg, Jenny; Jack, Susan; Dobbins, Maureen

    2010-03-01

    Poor or inconsistent research utilization into clinical practice is a recurrent theme across study contexts, rendering leaders disillusioned with how best to foster the uptake of research into nursing practice. This makes it imperative to look to new approaches. Research utilization involves a learning process engaging attitudes, beliefs, and behaviors; yet, this is often overlooked in approaches and models used to facilitate research use. This oversight may offer some explanation to the limited progress in research utilization to date. Transformation Theory offers an explanatory theory and specific strategies (critical reflection and critical discourse) to explore attitudes, beliefs, and behaviors so that they are understood, validated, and can better guide actions. The purpose of this article was to explore what Transformation Theory can contribute to research utilization initiatives in nursing practice. Transformation Theory and transformative learning strategies are discussed and critically analyzed in consideration of their potential roles in fostering research utilization in clinical nursing practice. (1) Research utilization is a learning process that involves knowledge, skills, feelings, attitudes, and beliefs. (2) Transformative learning strategies of critical reflection and discourse can facilitate insight into experiences, finding shared meanings among groups of people, and understanding/validating beliefs, attitudes, and feelings so they can more consciously guide future actions. This dimension is frequently neglected in research utilization efforts. (3) In combination with research utilization theories, Transformation Theory may be a missing link to make research utilization initiatives more effective in rendering and sustaining nursing practice change, thus enhancing client care and well-being. (4) Research and further consideration are both warranted and needed.

  9. High frequency vector-mediated transformation and gene replacement in Tetrahymena.

    PubMed Central

    Gaertig, J; Gu, L; Hai, B; Gorovsky, M A

    1994-01-01

    Recently, we developed a mass DNA-mediated transformation technique for the ciliated protozoan Tetrahymena thermophila that introduces transforming DNA by electroporation into conjugating cells. Other studies demonstrated that a neomycin resistance gene flanked by Tetrahymena H4-I gene regulatory sequences transformed Tetrahymena by homologous recombination within the H4-I locus when microinjected into the macronucleus. We describe the use of conjugant electrotransformation (CET) for gene replacement and for the development of new independently replicating vectors and a gene cassette that can be used as a selectable marker in gene knockout experiments. Using CET, the neomycin resistance gene flanked by H4-I sequences transformed Tetrahymena, resulting in the replacement of the H4-I gene or integrative recombination of the H4-I/neo/H4-I gene (but not vector sequences) in the 5' or 3' flanking region of the H4-I locus. Gene replacement was obtained with non-digested plasmid DNA but releasing the insert increased the frequency of replacement events about 6-fold. The efficiency of transformation by the H4-I/neo/H4-I selectable marker was unchanged when a single copy of the Tetrahymena rDNA replication origin was included on the transforming plasmid. However, the efficiency of transformation using CET increased greatly when a tandem repeat of the replication origin fragment was used. This high frequency of transformation enabled mapping of the region required for H4-I promoter function to within 333 bp upstream of the initiator ATG. Similarly approximately 300 bp of sequence downstream of the translation terminator TGA of the beta-tubulin 2 (BTU2) gene could substitute for the 3' region of the H4-I gene. This hybrid H4-I/neo/BTU2 gene did not transform Tetrahymena when subcloned on a plasmid lacking an origin of replication, but did transform at high frequency on a two origin plasmid. Thus, the H4-I/neo/BTU2 cassette is a selectable marker that can be used for gene

  10. In-field Raman amplification on coherent optical fiber links for frequency metrology.

    PubMed

    Clivati, C; Bolognini, G; Calonico, D; Faralli, S; Mura, A; Levi, F

    2015-04-20

    Distributed Raman amplification (DRA) is widely exploited for the transmission of broadband, modulated signals used in data links, but not yet in coherent optical links for frequency metrology, where the requirements are rather different. After preliminary tests on fiber spools, in this paper we deeper investigate Raman amplification on deployed in-field optical metrological links. We actually test a Doppler-stabilized optical link both on a 94 km-long metro-network implementation with multiplexed ITU data channels and on a 180 km-long dedicated fiber haul connecting two cities, where DRA is employed in combination with Erbium-doped fiber amplification (EDFA). The performance of DRA is detailed in both experiments, indicating that it does not introduce noticeable penalties for the metrological signal or for the ITU data channels. We hence show that Raman amplification of metrological signals can be compatible with a wavelength division multiplexing architecture and that it can be used as an alternative or in combination with dedicated bidirectional EDFAs. No deterioration is noticed in the coherence properties of the delivered signal, which attains frequency instability at the 10(-19) level in both cases. This study can be of interest also in view of the undergoing deployment of continental fiber networks for frequency metrology.

  11. Cascaded optical link on a telecommunication fiber network for ultra-stable frequency dissemination

    NASA Astrophysics Data System (ADS)

    Lopez, Olivier; Chiodo, Nicola; Stefani, Fabio; Wiotte, Fabrice; Quintin, Nicolas; Bercy, Anthony; Chardonnet, Christian; Santarelli, Giorgio; Pottie, Paul-Eric; Amy-Klein, Anne

    2015-03-01

    The transfer of ultra-stable frequencies between distant laboratories is required by many applications in time and frequency metrology, fundamental physics, particle accelerators and astrophysics. Optical fiber links have been intensively studied for a decade and brought the potential to transfer frequency with a very high accuracy and stability thanks to an active compensation of the propagation noise. We are currently developing an optical metrological network using the fibers of the French National Research and Education Network. Using the so-called dark-channel approach, the ultrastable signal is copropagating with data traffic using wavelength division multiplexing. Due to significant reflections and losses along the fibers, which cannot be compensated with amplifiers, we have developed some repeater stations for the metrological signal. These remotely-operated stations amplify the ultrastable signal and compensate the propagation noise. The link is thus composed of a few cascaded spans. It gives the possibility to increase the noise correction bandwidth, which is proportional to the inverse of the fiber length for each span. These stations are a key element for the deployment of a reliable and large scale metrological network. We report here on the implementation of a two-spans cascaded link of 740 km reaching a relative stability of a few 10-20 after 103 s averaging time. Extension to longer links and alternative transfer methods will be discussed.

  12. Transforming the Medical Subject Headings into Linked Data: Creating the Authorized Version of MeSH in RDF.

    PubMed

    Bushman, Barbara; Anderson, David; Fu, Gang

    In February 2014 the National Library of Medicine formed the Linked Data Infrastructure Working Group to investigate the potential for publishing linked data, determine best practices for publishing linked data, and prioritize linked data projects, beginning with transforming the Medical Subject Headings as a linked data pilot. This article will review the pilot project to convert the Medical Subject Headings from XML to RDF. It will discuss the collaborative process, the technical and organizational issues tackled, and the future of linked data at the library.

  13. Transforming the Medical Subject Headings into Linked Data: Creating the Authorized Version of MeSH in RDF

    PubMed Central

    Bushman, Barbara; Anderson, David; Fu, Gang

    2015-01-01

    In February 2014 the National Library of Medicine formed the Linked Data Infrastructure Working Group to investigate the potential for publishing linked data, determine best practices for publishing linked data, and prioritize linked data projects, beginning with transforming the Medical Subject Headings as a linked data pilot. This article will review the pilot project to convert the Medical Subject Headings from XML to RDF. It will discuss the collaborative process, the technical and organizational issues tackled, and the future of linked data at the library. PMID:26877832

  14. Compressive sensing-based channel bandwidth improvement in optical wireless orthogonal frequency division multiplexing link using visible light emitting diode.

    PubMed

    Won, Yong-Yuk; Yoon, Sang Min

    2014-08-25

    A new technique, which can compensate for the lack of channel bandwidth in an optical wireless orthogonal frequency division multiplexing (OFDM) link based on a light emitting diode (LED), is proposed. It uses an adaptive sampling and an inverse discrete cosine transform in order to convert an OFDM signal into a sparse waveform so that not only is the important data obtained efficiently but the redundancy one is removed. In compressive sensing (CS), a sparse signal that is sampled below the Nyquist/Shannon limit can be reconstructed successively with enough measurement. This means that the CS technique can increase the data rate of visible light communication (VLC) systems based on LEDs. It is observed that the data rate of the proposed CS-based VLC-OFDM link can be made 1.7 times greater than a conventional VLC-OFDM link (from 30.72 Mb/s to 51.2 Mb/s). We see that the error vector magnitude (EVM) of the quadrature phase shift keying (QPSK) symbol is 31% (FEC limit: EVM of 32%) at a compression ratio of 40%.

  15. High bandwidth real time frequency modulated (FM) video link for security and tactical applications

    SciTech Connect

    Lupinetti, F.

    1988-01-01

    With the increasing demand for in situ unmanned reconnaissance, security control, and intrusion detection, the capability of transmitting and receiving video information from remote locations has become of paramount importance. This capability can be achieved by appropriately deploying radio frequency (RF) video links which can readily be interfaced with sensors, humans, or other RF links. The video link described in this paper was designed and implemented for security and tactical applications which require a medium power, low complexity, rugged link capable of direct transmission and reception of FM modulated, high quality, full-color video signals in the low portion (470--806 MHz) of the UHF frequency band (300--3000 MHz). The transmitter portion of the link is tunable. It is of the direct modulation (FM and FR simultaneously) type. The receiver is of the direct detection type with no need for any downconversion. Both transmitter and receiver are currently being tested for mobile and fixed applications at the Sandia Robotic Vehicle Range. Ranges in excess of 10 Km and simultaneous transmission and reception of three adjacent channels have been achieved using omnidirectional antennas. 6 refs., 13 figs.

  16. High bandwidth real time frequency modulated (FM) video link for security and tactical applications

    SciTech Connect

    Lupinetti, F.

    1988-01-01

    With the increasing demand for in situ unmanned reconnaissance, security control, and intrusion detection, the capability of transmitting and receeiving video information from remote locations has become of paramount importance. This capability can be achieved by appropriately deploying radio frequency (RF) video links which can readily be interfaced with sensors, humans, or other RF links. The video link described in this paper was designed and implemented for security and tactical applications which require medium power, low complexity, rugged link capable of direct transmission and reception of FM modulated, high quality, full-color video signals in the low portion (470-806 MHz0 of the UHF frequency band (300-3000 MHz). The transmitter portion of the link is tubable. It is of the direct modulation (FM and RF simultaneously) type. The receiver is of the direct detection type with no need for any downconversion. Both transmitter and receiver are currently being tested for mobile and fixed applications at the Sandia Robotic Vehicle Rangle. Ranges in excess of 10 Km and simultaneous transmission and reception of three adjacent channels have been achieved using omnidirectional antennas.

  17. Participatory research with youth: idealising safe social spaces or building transformative links in difficult environments?

    PubMed

    Vaughan, Cathy

    2014-01-01

    Freire's theory of social change informs analysis of youth-focused participatory research, with researchers describing links between participation and young people's critical thinking. There is less analysis of how youth move from the safe social space of a participatory research project to take health-promoting action in difficult real-world contexts. This article analyses a project conducted with Papua New Guinean youth, disrupting assumptions that critical thinking inevitably leads to critical action on health. Findings suggest the need to shift the focus of participatory research from supporting 'safe social spaces' to supporting 'transformative action in context' to concretely contribute to improving youth health.

  18. Field oriented control of an induction machine in a high frequency link power system

    NASA Technical Reports Server (NTRS)

    Sul, Seung K.; Lipo, Thomas A.

    1988-01-01

    A field-oriented controlled induction machine drive operating with a high-frequency single-phase sinusoidal voltage link is presented. System performance is investigated by computer simulation and is verified by a test on a prototype system. A novel control loop to minimize the link voltage fluctuation is proposed. The capability of rapid demagnetization of the induction machine by current regulation is investigated. A current-modulation technique termed mode control is proposed, and its performance is compared with that of the conventional delta-modulation technique.

  19. 64 Gbit/s Transmission over 850 m Fixed Wireless Link at 240 GHz Carrier Frequency

    NASA Astrophysics Data System (ADS)

    Kallfass, Ingmar; Boes, Florian; Messinger, Tobias; Antes, Jochen; Inam, Anns; Lewark, Ulrich; Tessmann, Axel; Henneberger, Ralf

    2015-02-01

    A directive fixed wireless link operating at a center frequency of 240 GHz achieves a data rate of 64 Gbit/s over a transmission distance of 850 m using QPSK and 8PSK modulation, in a single-channel approach without the use of spatial diversity concepts. The analog transmit and receive frontend consists of active monolithic integrated circuits including broadband RF amplification and quadrature subharmonic mixer channels. The analog frontend is addressed by 64 GSa/s ADC and DAC boards, which are amenable to real-time data transmission. A link budget calculation allows for the estimation of the performance under adverse weather conditions.

  20. A Radio-Frequency-over-Fiber link for large-array radio astronomy applications

    NASA Astrophysics Data System (ADS)

    Mena, J.; Bandura, K.; Cliche, J.-F.; Dobbs, M.; Gilbert, A.; Tang, Q. Y.

    2013-10-01

    A prototype 425-850 MHz Radio-Frequency-over-Fiber (RFoF) link for the Canadian Hydrogen Intensity Mapping Experiment (CHIME) is presented. The design is based on a directly modulated Fabry-Perot (FP) laser, operating at ambient temperature, and a single-mode fiber. The dynamic performance, gain stability, and phase stability of the RFoF link are characterized. Tests on a two-element interferometer built at the Dominion Radio Astrophysical Observatory for CHIME prototyping demonstrate that RFoF can be successfully used as a cost-effective solution for analog signal transport on the CHIME telescope and other large-array radio astronomy applications.

  1. Wavelet packet transform-based optical orthogonal frequency-division multiplexing transmission using direct detection

    NASA Astrophysics Data System (ADS)

    Zhang, Hongbo; Yi, Xingwen; Chen, Lei; Zhang, Jing; Deng, Mingliang; Qiu, Kun

    2012-10-01

    As an alternate to fast Fourier transform-based orthogonal frequency-division multiplexing (OFDM), wavelet packet transform (WPT)-based OFDM (WPT-OFDM) does not require cyclic prefix to avoid inter-symbol-interference. The wavelet has many varieties and therefore, it can provide more freedom for system design to suit different applications. We propose a real-valued WPT-OFDM that uses intensity modulation/direct detection. We also conduct an experiment to verify its performance through a 75-km standard single-mode fiber.

  2. Frequency measurement of a Sr lattice clock using an SI-second-referenced optical frequency comb linked by a global positioning system (GPS)

    NASA Astrophysics Data System (ADS)

    Hong, Feng-Lei; Takamoto, Masao; Higashi, Ryoichi; Fukuyama, Yasuhiro; Jiang, Jie; Katori, Hidetoshi

    2005-07-01

    We have established a transportable frequency measurement system using an optical frequency comb linked to a commercial Cs atomic clock, which is in turn linked to international atomic time (TAI) through global positioning system (GPS) time. An iodine-stabilized Nd:YAG laser is used as a flywheel in the frequency measurement system. This system is used to measure the absolute frequency of the clock transition of 87Sr in an optical lattice. We obtained a fractional uncertainty of 2×10-14 in the frequency measurement with a total averaging time of ~ 105 s over 9 days.

  3. Frequency measurement of a Sr lattice clock using an SI-second-referenced optical frequency comb linked by a global positioning system (GPS).

    PubMed

    Hong, Feng-Lei; Takamoto, Masao; Higashi, Ryoichi; Fukuyama, Yasuhiro; Jiang, Jie; Katori, Hidetoshi

    2005-07-11

    We have established a transportable frequency measurement system using an optical frequency comb linked to a commercial Cs atomic clock, which is in turn linked to international atomic time (TAI) through global positioning system (GPS) time. An iodine-stabilized Nd:YAG laser is used as a flywheel in the frequency measurement system. This system is used to measure the absolute frequency of the clock transition of (87)Sr in an optical lattice. We obtained a fractional uncertainty of 2x10(-14) in the frequency measurement with a total averaging time of ~ 10(5) s over 9 days.

  4. Application of four wave mixing in precise radio frequency dissemination via optical fiber link

    NASA Astrophysics Data System (ADS)

    Lu, Xing; Lv, Zhiqiang; Chen, Xing; Gong, Zibo; Shi, Kebin

    2014-09-01

    We report on a new phase noise detection technique for radio frequency (RF) dissemination based on transferring mode locked laser pulses via optical fiber. The proposed approach is insusceptible to optical fiber interconnection reflection by combining optical frequency comb (OFC) expansion generated by four wave mixing (FWM) in dispersion shifted fiber (DSF) and wavelength division multiplexing (WDM) technique. An experimental system based on a fiber link of 100km was demonstrated. The measured fractional stability was 1.5×10-13 at 1s and 1.7×10-16 at 1000s.

  5. Off-resonance frequency operation for power transfer in a loosely coupled air core transformer

    DOEpatents

    Scudiere, Matthew B

    2012-11-13

    A power transmission system includes a loosely coupled air core transformer having a resonance frequency determined by a product of inductance and capacitance of a primary circuit including a primary coil. A secondary circuit is configured to have a substantially same product of inductance and capacitance. A back EMF generating device (e.g., a battery), which generates a back EMF with power transfer, is attached to the secondary circuit. Once the load power of the back EMF generating device exceeds a certain threshold level, which depends on the system parameters, the power transfer can be achieved at higher transfer efficiency if performed at an operating frequency less than the resonance frequency, which can be from 50% to 95% of the resonance frequency.

  6. Integrated frequency comb source based Hilbert transformer for wideband microwave photonic phase analysis.

    PubMed

    Nguyen, Thach G; Shoeiby, Mehrdad; Chu, Sai T; Little, Brent E; Morandotti, Roberto; Mitchell, Arnan; Moss, David J

    2015-08-24

    We demonstrate a photonic RF Hilbert transformer for broadband microwave in-phase and quadrature-phase generation based on an integrated frequency optical comb, generated using a nonlinear microring resonator based on a CMOS compatible, high-index contrast, doped-silica glass platform. The high quality and large frequency spacing of the comb enables filters with up to 20 taps, allowing us to demonstrate a quadrature filter with more than a 5-octave (3 dB) bandwidth and an almost uniform phase response.

  7. Star/linear polymer topology transformation facilitated by mechanical linking of polymer chains.

    PubMed

    Aoki, Daisuke; Uchida, Satoshi; Takata, Toshikazu

    2015-06-01

    Topology transformation of a star polymer to a linear polymer is demonstrated for the first time. A three-armed star polymer possessing a mechanical linking of two polymer chains was synthesized by the living ring-opening polymerization of δ-valerolactone initiated by a pseudo[2]rotaxane having three hydroxy groups as the initiator sites on the wheel component and at both axle termini. The polymerization was followed by the propagation end-capping reaction with a bulky isocyanate not only to prevent the wheel component deslippage but also to introduce the urethane moiety at the axle terminal. The resulting rotaxane-linked star polymer with a fixed rotaxane linkage based on the ammonium/crown ether interaction was subjected to N-acetylation of the ammonium moiety, which liberated the components from the interaction to move the wheel component to the urethane terminal as the interaction site, eventually affording the linear polymer. The physical property change caused by the present topology transformation was confirmed by the hydrodynamic volume and viscosity.

  8. Frequency domain volume rendering by the wavelet X-ray transform.

    PubMed

    Westenberg, M A; Roerdink, J M

    2000-01-01

    We describe a wavelet based X-ray rendering method in the frequency domain with a smaller time complexity than wavelet splatting. Standard Fourier volume rendering is summarized and interpolation and accuracy issues are briefly discussed. We review the implementation of the fast wavelet transform in the frequency domain. The wavelet X-ray transform is derived, and the corresponding Fourier-wavelet volume rendering algorithm (FWVR) is introduced, FWVR uses Haar or B-spline wavelets and linear or cubic spline interpolation. Various combinations are tested and compared with wavelet splatting (WS). We use medical MR and CT scan data, as well as a 3-D analytical phantom to assess the accuracy, time complexity, and memory cost of both FWVR and WS. The differences between both methods are enumerated.

  9. Time-frequency analysis of electroencephalogram series. II. Gabor and wavelet transforms

    NASA Astrophysics Data System (ADS)

    Blanco, S.; D'Attellis, C. E.; Isaacson, S. I.; Rosso, O. A.; Sirne, R. O.

    1996-12-01

    In this paper we compare two methods, based on the Gabor and wavelet transforms, to quantify and visualize the time evolution of frequency contents of electroencephalogram (EEG) time series. We found an optimal correlation between EEG visual inspection and the proposed methods in the characterization of the frequency and energy content of characteristic activity during an epileptic seizure. The quasimonofrequency behavior observed in the epileptic EEG series, in a previous work using a Gabor analysis [

    J. Inst. Electr. Eng. 93, 429 (1946)
    ], is confirmed with the analysis using a wavelet. Moreover, the method based on the wavelet transform allows us to build a detector of epileptic events. Both methods are exemplified with EEG series obtained with depth electrodes in refractory epileptic patients.

  10. Modular transformer state model for the simulation of high frequency spacecraft power systems

    NASA Astrophysics Data System (ADS)

    Evans, Bruce W.; Grigsby, L. L.; Nelms, R. M.

    A high frequency, lumped parameter model of a power transformer is presented. The model is used to derive a third-order state variable description of the device that is coupled to state variable models of the other power system components. Based on the state model, a digital simulation is conducted using the state transition matrix. The technique is used to simulate a high frequency spacecraft power system which includes a series resonant converter, transformer, transmission line, and resistive-inductive load. Each individual device is modeled as a two-port modular subnetwork with port voltages used as the independent variables. A state variable mathematical description of each device is formulated and numerically simulated using the state transition matrix. The results of the simulation are compared to results from EMTP, a program widely used by the power industry to predict transients.

  11. Chirp Z transform based enhanced frequency resolution for depth resolvable non stationary thermal wave imaging

    NASA Astrophysics Data System (ADS)

    Suresh, B.; Subhani, Sk.; Vijayalakshmi, A.; Vardhan, V. H.; Ghali, V. S.

    2017-01-01

    This paper proposes a novel post processing modality to enhance depth resolution in frequency modulated thermal wave imaging using chirp Z transform. It explores the spectral zooming feature of the proposed modality to enhance depth resolution and validates it through the experimentation carried over a carbon fiber reinforced plastic and mild steel specimens. Further, defect detection capability of the proposed modality has been compared with that of the other contemporary modalities by taking the defect signal to noise ratio into consideration.

  12. Chirp Z transform based enhanced frequency resolution for depth resolvable non stationary thermal wave imaging.

    PubMed

    Suresh, B; Subhani, Sk; Vijayalakshmi, A; Vardhan, V H; Ghali, V S

    2017-01-01

    This paper proposes a novel post processing modality to enhance depth resolution in frequency modulated thermal wave imaging using chirp Z transform. It explores the spectral zooming feature of the proposed modality to enhance depth resolution and validates it through the experimentation carried over a carbon fiber reinforced plastic and mild steel specimens. Further, defect detection capability of the proposed modality has been compared with that of the other contemporary modalities by taking the defect signal to noise ratio into consideration.

  13. Hydrodynamics selects the pathway for displacive transformations in DNA-linked colloidal crystallites.

    PubMed

    Jenkins, Ian C; Casey, Marie T; McGinley, James T; Crocker, John C; Sinno, Talid

    2014-04-01

    The degree to which DNA-linked particle crystals, particularly those composed of micrometer-scale colloids, are able to dynamically evolve or whether they are kinetically arrested after formation remains poorly understood. Here, we study a recently observed displacive transformation in colloidal binary superlattice crystals, whereby a body-centered cubic to face-centered cubic transformation is found to proceed spontaneously under some annealing conditions. Using a comprehensive suite of computer simulation tools, we develop a framework for analyzing the many displacive transformation pathways corresponding to distinct, but energetically degenerate, random hexagonal close-packed end states. Due to the short-ranged, spherically symmetric nature of the particle interactions the pathways are all barrierless, suggesting that all end states should be equally likely. Instead, we find that hydrodynamic correlations between particles result in anisotropic mobility along the various possible displacive pathways, strongly selecting for pathways that lead to the fcc-CuAu-I configuration, explaining recent experimental observations. This finding may provide clues for discovering new approaches for controlling structure in this emerging class of materials.

  14. Fourier Transform Ion Cyclotron Resonance Mass Spectrometry at the Cyclotron Frequency

    NASA Astrophysics Data System (ADS)

    Nagornov, Konstantin O.; Kozhinov, Anton N.; Tsybin, Yury O.

    2017-02-01

    The phenomenon of ion cyclotron resonance allows for determining mass-to-charge ratio, m/z, of an ensemble of ions by means of measurements of their cyclotron frequency, ω c . In Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), the ω c quantity is usually unavailable for direct measurements: the resonant state is located close to the reduced cyclotron frequency (ω+), whereas the ω c and the corresponding m/z values may be calculated via theoretical derivation from an experimental estimate of the ω+ quantity. Here, we describe an experimental observation of a new resonant state, which is located close to the ω c frequency and is established because of azimuthally-dependent trapping electric fields of the recently developed ICR cells with narrow aperture detection electrodes. We show that in mass spectra, peaks close to ω+ frequencies can be reduced to negligible levels relative to peaks close to ω c frequencies. Due to reduced errors with which the ω c quantity is obtained, the new resonance provides a means of cyclotron frequency measurements with precision greater than that achieved when ω+ frequency peaks are employed. The described phenomenon may be considered for a development into an FT-ICR MS technology with increased mass accuracy for applications in basic research, life, and environmental sciences.

  15. Time-frequency signal analysis for gearbox fault diagnosis using a generalized synchrosqueezing transform

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Liang, Ming

    2012-01-01

    The vibration data, especially those collected during the system run-up and run-down periods, contain rich information for gearbox condition monitoring. Time-frequency (TF) signal analysis is an effective tool to detect gearbox faults under varying shaft speed. However, the feature of the amplitude modulated-frequency modulated (AM-FM) gearbox fault signal usually cannot be directly extracted from the blurred time-frequency representation (TFR) caused by the time-varying frequency and noisy multicomponent measurement. As such, we propose to use a generalized synchrosqueezing transform (GST)-based TF method to detect and diagnose gearbox faults. With this method, the original vibration signal is first mapped into another analytical signal to facilitate synchrosqueezing of the TF picture. A time-scale domain restoration process is then applied to recover the instantaneous frequency profile with concentrated TFR. The gearbox fault, if any, can then be detected by observing the presence of the meshing frequency and sideband components in the TFR. The faulty gear can be identified via frequency relation analysis of AM-FM components. The proposed method is evaluated using both simulated and experimental gearbox vibration signals. The results show that the proposed approach is effective for gearbox condition monitoring.

  16. Fourier Transform Ion Cyclotron Resonance Mass Spectrometry at the Cyclotron Frequency.

    PubMed

    Nagornov, Konstantin O; Kozhinov, Anton N; Tsybin, Yury O

    2017-04-01

    The phenomenon of ion cyclotron resonance allows for determining mass-to-charge ratio, m/z, of an ensemble of ions by means of measurements of their cyclotron frequency, ω c . In Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), the ω c quantity is usually unavailable for direct measurements: the resonant state is located close to the reduced cyclotron frequency (ω+), whereas the ω c and the corresponding m/z values may be calculated via theoretical derivation from an experimental estimate of the ω+ quantity. Here, we describe an experimental observation of a new resonant state, which is located close to the ω c frequency and is established because of azimuthally-dependent trapping electric fields of the recently developed ICR cells with narrow aperture detection electrodes. We show that in mass spectra, peaks close to ω+ frequencies can be reduced to negligible levels relative to peaks close to ω c frequencies. Due to reduced errors with which the ω c quantity is obtained, the new resonance provides a means of cyclotron frequency measurements with precision greater than that achieved when ω+ frequency peaks are employed. The described phenomenon may be considered for a development into an FT-ICR MS technology with increased mass accuracy for applications in basic research, life, and environmental sciences. Graphical Abstract ᅟ.

  17. Reference Beam Pattern Design for Frequency Invariant Beamforming Based on Fast Fourier Transform.

    PubMed

    Zhang, Wang; Su, Tao

    2016-09-22

    In the field of fast Fourier transform (FFT)-based frequency invariant beamforming (FIB), there is still an unsolved problem. That is the selection of the reference beam to make the designed wideband pattern frequency invariant (FI) over a given frequency range. This problem is studied in this paper. The research shows that for a given array, the selection of the reference beam pattern is determined by the number of sensors and the ratio of the highest frequency to the lowest frequency of the signal (RHL). The length of the weight vector corresponding to a given reference beam pattern depends on the reference frequency. In addition, the upper bound of the weight length to ensure the FI property over the whole frequency band of interest is also given. When the constraints are added to the reference beam, it does not affect the FI property of the designed wideband beam as long as the symmetry of the reference beam is ensured. Based on this conclusion, a scheme for reference beam design is proposed.

  18. Reference Beam Pattern Design for Frequency Invariant Beamforming Based on Fast Fourier Transform

    PubMed Central

    Zhang, Wang; Su, Tao

    2016-01-01

    In the field of fast Fourier transform (FFT)-based frequency invariant beamforming (FIB), there is still an unsolved problem. That is the selection of the reference beam to make the designed wideband pattern frequency invariant (FI) over a given frequency range. This problem is studied in this paper. The research shows that for a given array, the selection of the reference beam pattern is determined by the number of sensors and the ratio of the highest frequency to the lowest frequency of the signal (RHL). The length of the weight vector corresponding to a given reference beam pattern depends on the reference frequency. In addition, the upper bound of the weight length to ensure the FI property over the whole frequency band of interest is also given. When the constraints are added to the reference beam, it does not affect the FI property of the designed wideband beam as long as the symmetry of the reference beam is ensured. Based on this conclusion, a scheme for reference beam design is proposed. PMID:27669242

  19. Multiphase Resistivity Model for Magnetic Nanocomposites Developed for High Frequency, High Power Transformation

    SciTech Connect

    DeGeorge, V; Shen, S; Ohodnicki, P; Andio, M; Mchenry, ME

    2013-12-05

    New power conversion systems that offer promise to transform electricity grids into unified interactive supply networks require high-resistivity soft-magnetic materials to allow for switching of magnetic materials at frequencies approaching 100 kHz for power transformation in the megawatt range. Amorphous and nanocomposite soft-magnetic materials, which represent the state of the art in terms of high power densities and low losses at high frequencies, have resistivities that depend on the structures and spatial distributions of multiple phases in thin ribbons. We present a multiphase resistivity model applicable to nanocomposite materials by considering an equivalent circuit approach considering paths through an amorphous, crystalline, and growth inhibitor shell phase. We detail: (a) identification of amorphous, crystalline, and shell phases; (b) consideration of the role of the morphology of each phase in an equivalent circuit model for the resistance; (c) a two-band model for the Fe/Co composition dependence of the resistivity in crystalline and amorphous phases; (d) a virtual bound state model for resistivity to explain increased resistivity due to early transition-metal growth inhibitors in the shell surrounding the nanocrystalline phase; and (e) disorder effects on amorphous phase resistivity. Experimental design and results for systems of interest in high-frequency power transformation are discussed in the context of our model including: (a) techniques for measurements of cross-section and density, (b) four-point probe and surface resistivity measurements, and (c) measurements in Fe- and Co-rich systems comparing amorphous and nanocomposite materials.

  20. Linked Learning as a High School Transformation Strategy: Organizational Structures and Leadership Behaviors That Support Lasting Change

    ERIC Educational Resources Information Center

    Weiss, Elizabeth Rocio

    2016-01-01

    Linked Learning is an approach that has proven effective in transforming the learning experiences for high school students. An instrumental case study was conducted in a large urban district in Southern California where district and school leaders implemented Linked Learning as a systemic high school reform initiative. Analysis of the data…

  1. Linked Learning as a High School Transformation Strategy: Organizational Structures and Leadership Behaviors That Support Lasting Change

    ERIC Educational Resources Information Center

    Weiss, Elizabeth Rocio

    2016-01-01

    Linked Learning is an approach that has proven effective in transforming the learning experiences for high school students. An instrumental case study was conducted in a large urban district in Southern California where district and school leaders implemented Linked Learning as a systemic high school reform initiative. Analysis of the data…

  2. On the Link Between Benevolent Sexism and Orgasm Frequency in Heterosexual Women.

    PubMed

    Harris, Emily Ann; Hornsey, Matthew J; Barlow, Fiona Kate

    2016-11-01

    Previous research on subclinical orgasmic difficulties among women has focused on intrapsychic and interpersonal variables, but little attention has been paid to the more distal ideological factors that might indirectly constrain sexual pleasure. We hypothesized that women's endorsement of a benevolently sexist worldview would be negatively associated with orgasm frequency. Specifically, we predicted that benevolent sexism would be associated with increased perceptions of male sexual selfishness. This perception of men as interested in their own sexual pleasure would then predict decreased willingness to ask a partner for sexual pleasure, which in turn would be associated with less frequent orgasms. We found support for our model across two studies (Study 1: N = 339; Study 2: N = 323). We did not, however, find a direct effect of benevolent sexism on orgasm frequency. We discuss possible additional variables linking benevolent sexism with orgasm frequency, implications, and future directions.

  3. Spatial transformation-enabled electromagnetic devices: from radio frequencies to optical wavelengths.

    PubMed

    Jiang, Zhi Hao; Turpin, Jeremy P; Morgan, Kennith; Lu, Bingqian; Werner, Douglas H

    2015-08-28

    Transformation optics provides scientists and engineers with a new powerful design paradigm to manipulate the flow of electromagnetic waves in a user-defined manner and with unprecedented flexibility, by controlling the spatial distribution of the electromagnetic properties of a medium. Using this approach, over the past decade, various previously undiscovered physical wave phenomena have been revealed and novel electromagnetic devices have been demonstrated throughout the electromagnetic spectrum. In this paper, we present versatile theoretical and experimental investigations on designing transformation optics-enabled devices for shaping electromagnetic wave radiation and guidance, at both radio frequencies and optical wavelengths. Different from conventional coordinate transformations, more advanced and versatile coordinate transformations are exploited here to benefit diverse applications, thereby providing expanded design flexibility, enhanced device performance, as well as reduced implementation complexity. These design examples demonstrate the comprehensive capability of transformation optics in controlling electromagnetic waves, while the associated novel devices will open up new paths towards future integrated electromagnetic component synthesis and design, from microwave to optical spectral regimes.

  4. Spatial transformation-enabled electromagnetic devices: from radio frequencies to optical wavelengths

    PubMed Central

    Jiang, Zhi Hao; Turpin, Jeremy P.; Morgan, Kennith; Lu, Bingqian; Werner, Douglas H.

    2015-01-01

    Transformation optics provides scientists and engineers with a new powerful design paradigm to manipulate the flow of electromagnetic waves in a user-defined manner and with unprecedented flexibility, by controlling the spatial distribution of the electromagnetic properties of a medium. Using this approach, over the past decade, various previously undiscovered physical wave phenomena have been revealed and novel electromagnetic devices have been demonstrated throughout the electromagnetic spectrum. In this paper, we present versatile theoretical and experimental investigations on designing transformation optics-enabled devices for shaping electromagnetic wave radiation and guidance, at both radio frequencies and optical wavelengths. Different from conventional coordinate transformations, more advanced and versatile coordinate transformations are exploited here to benefit diverse applications, thereby providing expanded design flexibility, enhanced device performance, as well as reduced implementation complexity. These design examples demonstrate the comprehensive capability of transformation optics in controlling electromagnetic waves, while the associated novel devices will open up new paths towards future integrated electromagnetic component synthesis and design, from microwave to optical spectral regimes. PMID:26217054

  5. Method of range profile for step frequency MMW radar based on wavelet transform power spectrum estimator

    NASA Astrophysics Data System (ADS)

    Li, Yuehua; Gao, Duntang; Shen, Qinghong; Li, Xingguo

    2001-11-01

    The method of range profile for step frequency MMW radar targets based on wavelet transform power spectrum estimator is studied. We show how the Fourier power spectrum can be detected by using the wavelet function coefficients (WFC) of the DWT. This method can successfully measure the power spectrum in samples for which traditional methods often fail because the sample are finite sized, have a complex geometry, or are varyingly sampled. We demonstrate that the spectrum features, such as the power law index, the magnitude, and the typical scales can be determined by the DWT reconstructed spectrum. We apply this method to the practical step frequency MMW radar target echo signals, and on the condition of the same sampling frequency and sampling data length, it can achieve one dimensional range profile with profile"s resolution superior to FFT"s, so the one dimensional range profile of targets can be analyzed with high resolution, the detail algorithm of range profiles spectrum estimation based on wavelet transforming multirange cells is proposed. Compare with FFT algorithm, using wavelet spectrum estimator of short data series, we can achieves high resolution, high accuracy, and low SNR threshold. The Experiment results make clear that the DWT estimator is a sensitive tool in range profile of step frequency MMW radar.

  6. Time frequency characterization of hand-transmitted, impulsive vibrations using analytic wavelet transform

    NASA Astrophysics Data System (ADS)

    Kim, Jay; Welcome, Daniel E.; Dong, Ren G.; Joon Song, Won; Hayden, Charles

    2007-11-01

    Current guidelines to assess health risk of hand-arm vibration are based on the frequency-weighted rms acceleration level, therefore do not fully consider the effect of temporal variations of the spectral energy. Time averaging effect involved with the frequency analysis may severely underestimate the risk of impact tools. A time-frequency ( T- F) analysis is necessary to characterize a highly transient signal whose spectral characteristics change rapidly in time. The analytic wavelet transform (AWT) is an ideal T- F analysis tool as it possesses the advantages of both the Fourier and wavelet transforms. The AWT is applied to acceleration signals measured from six tools, five impact type tools and one relatively steady-type tool, to explore possible improvements of the current risk assessment method of hand-arm vibration exposure. Based on the unique capability of the AWT, several new concepts including frequency-weighted time history, cumulative injury function, and cumulative injury index are defined in this study. Possible applications of these new concepts to hand-arm vibration research are described. Based on the results from this study, needs for future research are discussed.

  7. Is there a link between geomagnetic reversal frequency and paleointensity? A Bayesian approach

    NASA Astrophysics Data System (ADS)

    Ingham, E.; Heslop, D.; Roberts, A. P.; Hawkins, R.; Sambridge, M.

    2014-07-01

    Over the last 25 years, several studies have tested for a link between geomagnetic field intensity and reversal frequency. However, despite a large increase in the number of absolute paleointensity determinations, and improved methods for obtaining such data, two competing models have arisen. Here we employ a new tool for objectively analyzing paleomagnetic time series to investigate the possibility of a link between reversal frequency and paleointensity. Transdimensional Markov chain Monte Carlo techniques are applied to a quality-filtered version of the global paleointensity (PINT) database for the last 202 Myr to model long-term paleointensity behavior. A large ensemble of models is sampled, from which a final representative mean model is extracted. The resulting paleointensity model confirms published conclusions that the single-silicate crystal method gives significantly different results from more conventional whole rock paleointensity methods; this makes it difficult to jointly model the two data types in the same analysis. When the much larger whole rock data set is considered, a stable paleointensity of 5.46±0.28×1022 A/m2 for the last 202 Myr is consistent with the 95% confidence interval of the paleointensity model. Statistical tests indicate no significant correlation between reversal frequency and field intensity at the 0.05 level. However, this result is likely due to the characteristics of the PINT database rather than being a genuine, physically representative conclusion. Given the paucity of data and general state of the global paleointensity database, concerted efforts to increase the number of high-quality, well-dated paleointensity data are required before conclusions about a link between geomagnetic field intensity and reversal frequency can be confidently drawn.

  8. Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

    NASA Astrophysics Data System (ADS)

    Hu, M.; Bai, Y. Z.; Zhou, Z. B.; Li, Z. X.; Luo, J.

    2014-05-01

    The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided.

  9. Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

    SciTech Connect

    Hu, M.; Bai, Y. Z. Zhou, Z. B. Li, Z. X.; Luo, J.

    2014-05-15

    The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided.

  10. Extrapolation of band-limited frequency data using an iterative Hilbert-transform method and its application for Fourier-transform phase-modulation fluorometry

    NASA Astrophysics Data System (ADS)

    Iwata, Tetsuo; Shibata, Hironobu; Araki, Tsutomu

    2007-01-01

    We propose a new band-extrapolation method using an iterative Hilbert-transform procedure, which is applicable for band-limited complex-frequency data obtained from a Fourier-transform phase-modulation fluorometer (FT-PMF). Without the band limitation, the real and the imaginary parts of the complex-frequency data obtained from the FT-PMF form a Hilbert-transform pair because of causality. However, the Hilbert-transform relation cannot actually hold because of the inevitable band limitation in the instrument. In order to alleviate this problem, we propose the band-extrapolation method. First, the real part of the complex-frequency data is Hilbert-transformed and the partial frequency data inside the band are replaced by the imaginary ones actually measured while those outside are kept as they are. Next, the corrected imaginary-frequency data are inverse-Hilbert-transformed again and the real-frequency data inside the band are replaced by those measured while those outside are kept. Such a procedure is iterated until changes in shapes of respective frequency waveforms are sufficiently small. Finally, we can obtain a desired time-domain waveform by the inverse Fourier transform of the pair of the extrapolated complex-frequency data. Numerical simulations showed that the proposed method was valid. A good agreement between two fluorescence decay waveforms of fluo-5N in calcium ion buffer, one obtained from the proposed method and the other obtained from the conventional time-correlated single-photon counting method, showed that the proposed method was useful.

  11. Linking magma reservoir processes to the frequency and magnitude of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Sheldrake, Tom; Caricchi, Luca

    2016-04-01

    The frequency of volcanic eruptions is fundamentally related to processes controlling the accumulation of eruptible magma at depth and the pressurisation of the magmatic reservoir. Here we present a combined statistical-empirical approach to link the frequency and magnitude of volcanic eruptions observed in different arcs to important parameters controlling the growth of subvolcanic reservoirs of eruptible magma. Such understanding is important for two reasons; firstly it presents an insight into how and why the frequency of eruptions varies between different groups of volcanoes; and secondly, it provides constraints for models that are used to interpret geochemical and geophysical data. To perform the analysis we further develop an analytical model that uses a Monte Carlo sampling approach to simulate the accumulation and eruption of magmatic reservoirs (Caricchi et al., 2014). By inverting the geological record of volcanic eruptions we can solve the Monte Carlo model to quantify parameters such as magma input and frequency of magma injection. Our results indicate systematic variation in the frequency of eruptions of various magnitudes between exchangeable groups of volcanoes, which can be related to variations of parameters such as average magma fluxes and thickness of the crust. Caricchi, L., C. Annen, J. Blundy, G. Simpson, and V. Pinel, 2014, Nature Geoscience, v. 7, no. 2, p. 126-130, doi:10.1038/ngeo2041.

  12. Use of dual-frequency microwave links for measuring path-averaged rainfall

    NASA Astrophysics Data System (ADS)

    Rahimi, A. R.; Holt, A. R.; Upton, G. J. G.; Cummings, R. J.

    2003-08-01

    Results are presented from an experiment designed to test the use of dual-frequency microwave attenuation for measuring path-averaged rainfall. In general, the relation between attenuation and path-averaged rainfall is nonlinear. However, for carefully chosen pairs of frequencies, the relation between the difference in attenuations and path-averaged rainfall is well represented by a straight line through the origin. The slope of this line is essentially unaffected by variations in the (unknown) drop size distribution, drop shape, and drop temperature. This paper describes the results obtained from a pair of links operating at 12.8 GHz and 17.6 GHz on a 23.3 km path. Results are shown for three individual events, including comparisons with rainfall estimates obtained from more traditional sources: a local rain gauge network and an adjacent weather radar. We report summary results for 112 events recorded on this path during almost 2 years of observation, and also for 52 events recorded on a nearby 13.9 km path operating at 13.9 GHz and 22.9 GHz. In both cases the results suggest that dual-frequency links could serve as useful additional tools for the measurement of rainfall, particularly in locations such as urban areas and obscured mountain valleys, where traditional measuring instruments struggle to provide accurate estimates.

  13. Phase fluctuation compensation for long-term transfer of stable radio frequency over fiber link.

    PubMed

    Ning, Bo; Du, Peng; Hou, Dong; Zhao, Jianye

    2012-12-17

    We developed a new radio frequency dissemination system based on an optical fiber link. A 1.55 μm mode-locked fiber laser was used as optical transmitter in the system. To actively reduce the phase fluctuation induced by the fiber length variations with high resolution, we proposed a novel compensation technique. In our technique, we directly control the phase of optical pulses generated by the laser to compensate the fluctuation. The phase-controlling method is based on both pump power modulation and cavity length adjusting. We performed the transfer in a 22-km outdoor fiber link, with a transfer stability of 3.7 × 10(-14) at 1 s and 6.6 × 10(-18) at 16000 s. The integrated timing jitter in 24 hours was reduced from 14 ps to 35 fs.

  14. A transcriptional regulator linking quorum sensing and chitin induction to render Vibrio cholerae naturally transformable

    PubMed Central

    Lo Scrudato, Mirella; Blokesch, Melanie

    2013-01-01

    The human pathogen Vibrio cholerae is an aquatic bacterium associated with zooplankton and their chitinous exoskeletons. On chitinous surfaces, V. cholerae initiates a developmental programme, known as natural competence, to mediate transformation, which is a mode of horizontal gene transfer. Competence facilitates the uptake of free DNA and recombination into the bacterial genome. Recent studies have indicated that chitin surfaces are required, but not sufficient to induce competence. Two additional regulatory pathways, i.e. catabolite repression and quorum sensing (QS), are components of the regulatory network that controls natural competence in V. cholerae. In this study, we investigated the link between chitin induction and QS. We show that the major regulators of these two pathways, TfoX and HapR, are both involved in the activation of a gene encoding a transcriptional regulator of the LuxR-type family, which we named QS and TfoX-dependent regulator (QstR). We demonstrate that HapR binds the promoter of qstR in a site-specific manner, indicating a role for HapR as an activator of qstR. In addition, epistasis experiments indicate that QstR compensates for the absence of HapR. We also provide evidence that QstR is required for the proper expression of a small but essential subset of competence genes and propose a new regulatory model in which QstR links chitin-induced TfoX activity with QS. PMID:23382174

  15. Fourier transform Infrared spectroscopic characterization of mineralizing type I collagen enzymatic trivalent cross-links.

    PubMed

    Paschalis, E P; Gamsjaeger, S; Tatakis, D N; Hassler, N; Robins, S P; Klaushofer, K

    2015-01-01

    The most abundant protein of bone's organic matrix is collagen. One of its most important properties is its cross-linking pattern, which is responsible for the fibrillar matrices' mechanical properties such as tensile strength and viscoelasticity. We have previously described a spectroscopic method based on the resolution of the Amide I and II Fourier transform Infrared (FTIR) bands to their underlying constituent peaks, which allows the determination of divalent and pyridinoline (PYD) collagen cross-links in mineralized thin bone tissue sections with a spatial resolution of ~6.3 μm. In the present study, we used FTIR analysis of a series of biochemically characterized collagen peptides, as well as skin, dentin, and predentin, to examine the potential reasons underlying discrepancies between two different analytical methodologies specifically related to spectral processing. The results identified a novel distinct FTIR underlying peak at ~1,680 cm(-1), correlated with deoxypyridinoline (DPD) content. Furthermore, the two different methods of spectral resolution result in widely different results, while only the method employing well-established spectroscopic routines for spectral resolution provided biologically relevant results, confirming our earlier studies relating the area of the underlying 1,660 cm(-1) with PYD content. The results of the present study describe a new peak that may be used to determine DPD content, confirm our earlier report relating spectroscopic parameters to PYD content, and highlight the importance of the selected spectral resolution methodology.

  16. Implementation guidance for industrial-level security systems using radio frequency alarm links

    SciTech Connect

    Swank, R.G.

    1996-07-12

    Spread spectrum (SS) RF transmission technologies have properties that make the transmitted signal difficult to intercept, interpret, and jam. The digital code used in the modulation process results in a signal that has high reception reliability and supports multiple use of frequency bands and selective addressing. These attributes and the relatively low installation cost of RF systems make SSRF technologies candidate for communications links in security systems used for industrial sites, remote locations, and where trenching or other disturbances of soil or structures may not be desirable or may be costly. This guide provides a description of such a system and presents implementation methods that may be of engineering benefit.

  17. Using Absolute Average Difference (DABS) in Interpreting the Frequency Response of Distribution Transformer

    NASA Astrophysics Data System (ADS)

    Yousof, M. F. M.; Ahmad, H.; Yaacob, M. M.; Eyam, A.; Muhammad, S.; Ahmed, S. S.

    2017-08-01

    Different numerical indices have been proposed in different works to analyze the Frequency Response Analysis measurements, such as Standard Deviation, Spectrum Deviation, Absolute Sum of Logarithmic Error, and Correlation Coefficient. A comparative evaluation of absolute average difference (DABS) index on the same footing appears to have not yet been reported. In this paper, DABS is amongst the five numerical indices used in interpreting FRA that have been evaluated for their respective suitability, reliability and sensitivity based on the same test cases involving winding deformation of real life power transformers. It was found that DABS and ASLE are the most reliable and sensitive index for various transformer faulty conditions. On the other hand, CC is the least reliable index as it could not indicate faulty winding on most presented cases.

  18. Two-dimensional SPICE-linked multiresolution impedance method for low-frequency electromagnetic interactions.

    PubMed

    Eberdt, Michael; Brown, Patrick K; Lazzi, Gianluca

    2003-07-01

    A multiresolution impedance method for the solution of low-frequency electromagnetic interaction problems typically encountered in bioelectromagnetics is presented. While the impedance method in its original form is based on the discretization of the scattering objects into equal-sized cells, our formulation decreases the number of unknowns by using an automatic mesh generation method that does not yield equal-sized cells in the modeling space. Results indicate that our multiresolution mesh generation scheme can provide a 50%-80% reduction in cell count, providing new opportunities for the solution of low-frequency bioelectromagnetic problems that require a high level of detail only in specific regions of the modeling space. Furthermore, linking the mesh generator to a circuit simulator such as SPICE permits the addition of arbitrarily complex passive and active circuit elements to the generated impedance network, opening the door to significant advances in the modeling of bioelectromagnetic phenomena.

  19. High frequency regeneration via direct somatic embryogenesis and efficient Agrobacterium- mediated genetic transformation of tobacco

    PubMed Central

    Pathi, Krishna Mohan; Tula, Suresh; Tuteja, Narendra

    2013-01-01

    A direct somatic embryogenesis protocol was developed for four cultivars of Nicotiana species, by using leaf disc as an explant. Direct somatic embryogenesis of Nicotiana by using BAP and IAA has not been investigated so far. This method does not require formation of callus tissues which leads to somaclonal variations. The frequency of somatic embryogenesis was strongly influenced by the plant growth hormones. The somatic embryos developing directly from explant tissue were noticed after 6 d of culture. Somatic embryogenesis of a high frequency (87–96%) was observed in cultures of the all four genotypes (Nicotiana tabacum, N. benthamiyana, N. xanthi, N. t cv petihavana). The results showed that the best medium for direct somatic embryogenesis was MS supplemented with 2.5 mg/l, 0.2 mg/l IAA and 2% sucrose. Subculture of somatic embryos onto hormone free MS medium resulted in their conversion into plants for all genotypes. About 95% of the regenerated somatic embryos germinated into complete plantlets. The plants showed morphological and growth characteristics similar to those of seed-derived plants. Explants were transformed using Agrobacterium tumifacious LBA4404 plasmid pCAMBIA1301 harboring the GUS gene. The regenerated transgenic plants were confirmed by PCR analysis and histochemical GUS assay. The transformation efficiency obtained by using the Agrobacterium- mediated transformation was more than 95%. This method takes 6 wk to accomplish complete transgenic plants through direct somatic embryogenesis. The transgenic plantlets were acclimatized successfully with 98% survival in greenhouse and they showed normal morphological characteristics and were fertile. The regeneration and transformation method described herein is very simple, highly efficient and fast for the introduction of any foreign gene directly in tobacco through direct somatic embryogenesis. PMID:23518589

  20. Transformed eddy-PV flux and positive synoptic eddy feedback onto low-frequency flow

    NASA Astrophysics Data System (ADS)

    Ren, Hong-Li; Jin, Fei-Fei; Kug, Jong-Seong; Gao, Li

    2011-06-01

    Interaction between synoptic eddy and low-frequency flow (SELF) has been the subject of many studies. In this study, we further examine the interaction by introducing a transformed eddy-potential-vorticity (TEPV) flux that is obtained from eddy-potential-vorticity flux through a quasi-geostrophic potential-vorticity inversion. The main advantage of using the TEPV flux is that it combines the effects of the eddy-vorticity and heat fluxes into the net acceleration of the low-frequency flow in such a way that the TEPV flux tends to be analogous to the eddy-vorticity fluxes in the barotropic framework. We show that the anomalous TEPV fluxes are preferentially directed to the left-hand side of the low-frequency flow in all vertical levels throughout the troposphere for monthly flow anomalies and for climate modes such as the Arctic Oscillation (AO). Furthermore, this left-hand preference of the TEPV flux direction is a convenient three-dimensional indicator of the positive reinforcement of the low-frequency flow by net eddy-induced acceleration. By projecting the eddy-induced net accelerations onto the low-frequency flow anomalies, we estimate the eddy-induced growth rates for the low frequency flow anomalies. This positive eddy-induced growth rate is larger (smaller) in the lower (upper) troposphere. The stronger positive eddy feedback in the lower troposphere may play an important role in maintaining an equivalent barotropic structure of the low-frequency atmospheric flow by balancing some of the strong damping effect of surface friction.

  1. Transformed Eddy-PV Flux and Positive Synoptic Eddy Feedback onto Low-Frequency Flow

    NASA Astrophysics Data System (ADS)

    Ren, H.; Jin, F.; Kug, J.; Gao, L.

    2010-12-01

    Interaction between synoptic eddy and low-frequency flow (SELF) has been the subject of many studies. In this study, we further examine the interaction by introducing a transformed eddy-potential-vorticity (TEPV) flux that is obtained from eddy-potential-vorticity flux through a quasi-geostrophic potential-vorticity inversion. The main advantage of using the TEPV flux is that it combines the effects of the eddy-vorticity and heat fluxes into the net acceleration of the low-frequency flow in such a way that the TEPV flux tends to be analogous to the eddy-vorticity fluxes in the barotropic framework. We show that the anomalous TEPV fluxes are preferentially directed to the left-hand side of the low-frequency flow in all vertical levels throughout the troposphere for monthly flow anomalies and for climate modes such as the Arctic Oscillation (AO). Furthermore, this left-hand preference of the TEPV flux direction is a convenient three-dimensional indicator of the positive reinforcement of the low-frequency flow by net eddy-induced acceleration. By projecting the eddy-induced net accelerations onto the low-frequency flow anomalies, we estimate the eddy-induced growth rates for the low frequency flow anomalies. This positive eddy-induced growth rate is larger (smaller) in the lower (upper) troposphere. The stronger positive eddy feedback in the lower troposphere may play an important role in maintaining an equivalent barotropic structure of the low-frequency atmospheric flow by balancing some of the strong damping effect of surface friction.

  2. Is there a Link Between Geomagnetic Reversal Frequency and Paleointensity? A Bayesian Approach

    NASA Astrophysics Data System (ADS)

    Ingham, E. M.; Heslop, D.; Roberts, A. P.; Hawkins, R.

    2013-12-01

    Over the last 25 years several studies have tested for a link between geomagnetic field intensity and reversal frequency. However, despite a large increase in the number of absolute paleointensity estimates available, and improved methods for obtaining such data, no conclusive evidence has been found for such a link. Here, we employ a new tool for objectively analyzing paleomagnetic time series to investigate the possibility of a link between reversal frequency and paleointensity. Reverse Jump Markov Chain Monte Carlo analysis is a Bayesian approach to sampling for model inference in problems with variable dimension. The Reverse Jump method is applied to a quality filtered version of the global paleointensity database for the last 202 My to identify rapid changes, known as change points, in the Earth's paleointensity, and to model long-term paleointensity behavior. A transdimensional Markov Chain is used to generate a large number of paleointensity models with a variable number and position of change points. A final mean paleointensity model, along with an estimate of the associated uncertainty, is extracted from this ensemble of models. The resulting paleointensity model for 0-202 Ma contains spikes at around the ages of records that were obtained using the single silicate crystal paleointensity method. This suggests that the single silicate crystal method gives significantly different results from the more conventional whole rock paleointensity methods, which makes it difficult to include the two data types in the same analysis. When single silicate crystal data are omitted from the dataset, no large change points are identified and a stable paleointensity of 5.46 × 0.28 x 10^22 A/m^2 is consistent with the 95% confidence interval of the mean paleointensity model for the period spanning the interval from 202 to 10 My. The modeled paleointensity has no distinct variability between times of high reversal frequency, such as the late Jurassic, and low reversal

  3. Temporal frequency deficits in the electroretinogram of the cone system in X-linked retinoschisis.

    PubMed

    Alexander, K R; Fishman, G A; Grover, S

    2000-01-01

    We investigated the extent of, and basis for, abnormalities in the flicker electroretinogram (ERG) of the cone system of patients with X-linked retinoschisis (XLRS), a form of hereditary vitreoretinal degeneration. ERGs were recorded from six patients with XLRS and from six visually normal subjects using high-contrast sinusoidal flicker that ranged in temporal frequency from 8 to 96 Hz, and that was presented against a rod-desensitizing adapting field. Compared to the control subjects, the patients with XLRS showed a significant reduction in the amplitude of the ERG response fundamental at temporal frequencies of 32 Hz and higher. In addition, their response phases were at or below the lower limits of normal (representing a phase lag) for temporal frequencies greater than 8 Hz. The higher harmonics of the patients' ERG responses to a low frequency stimulus were attenuated over the same temporal frequency range as was the response fundamental. This finding indicates that a major component of the abnormal temporal filtering responsible for the ERG abnormalities in XLRS occurs beyond the level of the early retinal nonlinearity that generates the harmonic components of the ERG response, and therefore is most likely postreceptoral in origin. Consistent with this interpretation, the ERG waveforms of the XLRS patients showed a significant attenuation of the ON-response component, with a normal OFF response. The overall pattern of results suggests that the marked reduction of ERG response amplitudes and the phase lag at the higher temporal frequencies in XLRS stem, at least in part, from a predominant attenuation of the ON-bipolar cell contribution to the flicker ERG.

  4. On the links between meteorological variables, aerosols, and tropical cyclone frequency in individual ocean basins

    NASA Astrophysics Data System (ADS)

    Chiacchio, Marc; Pausata, Francesco S. R.; Messori, Gabriele; Hannachi, Abdel; Chin, Mian; Önskog, Thomas; Ekman, Annica M. L.; Barrie, Leonard

    2017-01-01

    A generalized linear model based on Poisson regression has been used to assess the impact of environmental variables modulating tropical cyclone frequency in six main cyclone development areas: the East Pacific, West Pacific, North Atlantic, North Indian, South Indian, and South Pacific. The analysis covers the period 1980-2009 and focuses on widely used meteorological parameters including wind shear, sea surface temperature, and relative humidity from different reanalyses as well as aerosol optical depth for different compounds simulated by the Goddard Chemistry Aerosol Radiation and Transport model. Circulation indices are also included. Cyclone frequency is obtained from the International Best Track Archive for Climate Stewardship. A strong link is found between cyclone frequency and the relative sea surface temperature, Atlantic Meridional Mode, and wind shear with significant explained log likelihoods in the North Atlantic of 37%, 27%, and 28%, respectively. A significant impact of black carbon and organic aerosols on cyclone frequency is found over the North Indian Ocean, with explained log likelihoods of 27%. A weaker but still significant impact is found for observed dust aerosols in the North Atlantic with an explained log likelihood of 11%. Changes in lower stratospheric temperatures explain 28% of the log likelihood in the North Atlantic. Lower stratospheric temperatures from a subset of Coupled Model Intercomparison Project Phase 5 models properly simulate the warming and subsequent cooling of the lower stratosphere that follows a volcanic eruption but underestimates the cooling by about 0.5°C.

  5. An automatic frequency control loop using overlapping DFTs (Discrete Fourier Transforms)

    NASA Technical Reports Server (NTRS)

    Aguirre, S.

    1988-01-01

    An automatic frequency control (AFC) loop is introduced and analyzed in detail. The new scheme is a generalization of the well known Cross Product AFC loop that uses running overlapping discrete Fourier transforms (DFTs) to create a discriminator curve. Linear analysis is included and supported with computer simulations. The algorithm is tested in a low carrier to noise ratio (CNR) dynamic environment, and the probability of loss of lock is estimated via computer simulations. The algorithm discussed is a suboptimum tracking scheme with a larger frequency error variance compared to an optimum strategy, but offers simplicity of implementation and a very low operating threshold CNR. This technique can be applied during the carrier acquisition and re-acquisition process in the Advanced Receiver.

  6. A Novel Application of Fourier Transform Spectroscopy with HEMT Amplifiers at Microwave Frequencies

    NASA Technical Reports Server (NTRS)

    Wilkinson, David T.; Page, Lyman

    1995-01-01

    The goal was to develop cryogenic high-electron-mobility transistor (HEMT) based radiometers and use them to measure the anisotropy in the cosmic microwave background (CMB). In particular, a novel Fourier transform spectrometer (FTS) built entirely of waveguide components would be developed. A dual-polarization Ka-band HEMT radiometer and a similar Q-band radiometer were built. In a series of measurements spanning three years made from a ground-based site in Saskatoon, SK, the amplitude, frequency spectrum, and spatial frequency spectrum of the anisotropy were measured. A prototype Ka-band FTS was built and tested, and a simplified version is proposed for the MAP satellite mission. The 1/f characteristics of HEMT amplifiers were quantified using correlation techniques.

  7. Continuous-wave frequency comb Fourier transform source based on a high-dispersion cavity.

    PubMed

    Kraetschmer, Thilo; Walewski, Joachim W; Sanders, Scott T

    2006-11-01

    A dispersive grating compressor was included in a fiber ring laser to generate an unequally spaced frequency comb spanning approximately 1549-1552 nm. Beating of nearby modes in the comb naturally assigns unique amplitude modulation frequencies to each spectral component emitted. The source contains no moving parts. The single-mode fiber-coupled output is directed through hydrogen cyanide gas and detected by a photodiode. A Fourier transform of a 1 ms record yields a spectrum that agrees with results from a grating spectrometer at 0.06 nm resolution. By engineering stable, broadband combs, the technique could result in a universal and simple approach for spectroscopy at almost arbitrary measurement speeds and spectral resolutions limited only by Fourier principles.

  8. Automating identification of avian vocalizations using time-frequency information extracted from the Gabor transform.

    PubMed

    Connor, Edward F; Li, Shidong; Li, Steven

    2012-07-01

    Based on the Gabor transform, a metric is developed and applied to automatically identify bird species from a sample of 568 digital recordings of songs/calls from 67 species of birds. The Gabor frequency-amplitude spectrum and the Gabor time-amplitude profile are proposed as a means to characterize the frequency and time patterns of a bird song. An approach based on template matching where unknown song clips are compared to a library of known song clips is used. After adding noise to simulate the background environment and using an adaptive high-pass filter to de-noise the recordings, the successful identification rate exceeded 93% even at signal-to-noise ratios as low as 5 dB. Bird species whose songs/calls were dominated by low frequencies were more difficult to identify than species whose songs were dominated by higher frequencies. The results suggest that automated identification may be practical if comprehensive libraries of recordings that encompass the vocal variation within species can be assembled.

  9. Different dynamic resting state fMRI patterns are linked to different frequencies of neural activity.

    PubMed

    Thompson, Garth John; Pan, Wen-Ju; Keilholz, Shella Dawn

    2015-07-01

    Resting state functional magnetic resonance imaging (rsfMRI) results have indicated that network mapping can contribute to understanding behavior and disease, but it has been difficult to translate the maps created with rsfMRI to neuroelectrical states in the brain. Recently, dynamic analyses have revealed multiple patterns in the rsfMRI signal that are strongly associated with particular bands of neural activity. To further investigate these findings, simultaneously recorded invasive electrophysiology and rsfMRI from rats were used to examine two types of electrical activity (directly measured low-frequency/infraslow activity and band-limited power of higher frequencies) and two types of dynamic rsfMRI (quasi-periodic patterns or QPP, and sliding window correlation or SWC). The relationship between neural activity and dynamic rsfMRI was tested under three anesthetic states in rats: dexmedetomidine and high and low doses of isoflurane. Under dexmedetomidine, the lightest anesthetic, infraslow electrophysiology correlated with QPP but not SWC, whereas band-limited power in higher frequencies correlated with SWC but not QPP. Results were similar under isoflurane; however, the QPP was also correlated to band-limited power, possibly due to the burst-suppression state induced by the anesthetic agent. The results provide additional support for the hypothesis that the two types of dynamic rsfMRI are linked to different frequencies of neural activity, but isoflurane anesthesia may make this relationship more complicated. Understanding which neural frequency bands appear as particular dynamic patterns in rsfMRI may ultimately help isolate components of the rsfMRI signal that are of interest to disorders such as schizophrenia and attention deficit disorder.

  10. Different dynamic resting state fMRI patterns are linked to different frequencies of neural activity

    PubMed Central

    Thompson, Garth John; Pan, Wen-Ju

    2015-01-01

    Resting state functional magnetic resonance imaging (rsfMRI) results have indicated that network mapping can contribute to understanding behavior and disease, but it has been difficult to translate the maps created with rsfMRI to neuroelectrical states in the brain. Recently, dynamic analyses have revealed multiple patterns in the rsfMRI signal that are strongly associated with particular bands of neural activity. To further investigate these findings, simultaneously recorded invasive electrophysiology and rsfMRI from rats were used to examine two types of electrical activity (directly measured low-frequency/infraslow activity and band-limited power of higher frequencies) and two types of dynamic rsfMRI (quasi-periodic patterns or QPP, and sliding window correlation or SWC). The relationship between neural activity and dynamic rsfMRI was tested under three anesthetic states in rats: dexmedetomidine and high and low doses of isoflurane. Under dexmedetomidine, the lightest anesthetic, infraslow electrophysiology correlated with QPP but not SWC, whereas band-limited power in higher frequencies correlated with SWC but not QPP. Results were similar under isoflurane; however, the QPP was also correlated to band-limited power, possibly due to the burst-suppression state induced by the anesthetic agent. The results provide additional support for the hypothesis that the two types of dynamic rsfMRI are linked to different frequencies of neural activity, but isoflurane anesthesia may make this relationship more complicated. Understanding which neural frequency bands appear as particular dynamic patterns in rsfMRI may ultimately help isolate components of the rsfMRI signal that are of interest to disorders such as schizophrenia and attention deficit disorder. PMID:26041826

  11. High frequence and automatic link establishment (HF and ALE) radio propagation test to Antarctica

    NASA Astrophysics Data System (ADS)

    Gilles, P. E.; Katan, J. R.; Pease, B. L.

    1994-02-01

    Recent federal/military standards in the area of automatic link establishment (ALE) for HF radios have been developed that coordinate frequency selection between communicating terminals, allowing them to adapt to skywave conditions. This study focused on evaluating the utility of these state-of-the-art radios in the polar environment. A quick-look evaluation of this technology was demonstrated over a radio circuit between Christchurch, New Zealand, and McMurdo Station, Antarctica. This transauroral link, operated by the U.S. Navy for the National Science Foundation, is the primary link for all operational, logistical, and emergency communications for U.S. operations between the Antarctic and the outside world. Daily plots of the measured signal to noise ratio, probability of bit error, and channel quality are presented and analyzed. Because of the initial success of this technology demonstration, additional experiments were designed for deployment in FY 1993 to answer not only operational issues, but also to collect data for further scientific studies and engineering improvements.

  12. Non-contact radio frequency shielding and wave guiding by multi-folded transformation optics method

    PubMed Central

    Madni, Hamza Ahmad; Zheng, Bin; Yang, Yihao; Wang, Huaping; Zhang, Xianmin; Yin, Wenyan; Li, Erping; Chen, Hongsheng

    2016-01-01

    Compared with conventional radio frequency (RF) shielding methods in which the conductive coating material encloses the circuits design and the leakage problem occurs due to the gap in such conductive material, non-contact RF shielding at a distance is very promising but still impossible to achieve so far. In this paper, a multi-folded transformation optics method is proposed to design a non-contact device for RF shielding. This “open-shielded” device can shield any object at a distance from the electromagnetic waves at the operating frequency, while the object is still physically open to the outer space. Based on this, an open-carpet cloak is proposed and the functionality of the open-carpet cloak is demonstrated. Furthermore, we investigate a scheme of non-contact wave guiding to remotely control the propagation of surface waves over any obstacles. The flexibilities of such multi-folded transformation optics method demonstrate the powerfulness of the method in the design of novel remote devices with impressive new functionalities. PMID:27841358

  13. Long-term polar motion prediction using normal time-frequency transform

    NASA Astrophysics Data System (ADS)

    Su, Xiaoqing; Liu, Lintao; Houtse, Hsu; Wang, Guocheng

    2014-02-01

    This paper presents normal time-frequency transform (NTFT) application in harmonic/quasi-harmonic signal prediction. Particularly, we use the normal wavelet transform (a special NTFT) to make long-term polar motion prediction. Instantaneous frequency, phase and amplitude of Chandler wobble, prograde and retrograde annual wobbles of Earth's polar motion are analyzed via the NTFT. Results show that the three main wobbles can be treated as quasi-harmonic processes. Current instantaneous harmonic information of the three wobbles can be acquired by the NTFT that has a kernel function constructed with a normal half-window function. Based on this information, we make the polar motion predictions with lead times of 1 year and 5 years. Results show that our prediction skills are very good with long lead time. An abnormality in the predictions occurs during the second half of 2005 and first half of 2006. Finally, we provide the future (starting from 2013) polar motion predictions with 1- and 5-year leads. These predictions will be used to verify the effectiveness of the method proposed in this paper.

  14. Non-contact radio frequency shielding and wave guiding by multi-folded transformation optics method.

    PubMed

    Madni, Hamza Ahmad; Zheng, Bin; Yang, Yihao; Wang, Huaping; Zhang, Xianmin; Yin, Wenyan; Li, Erping; Chen, Hongsheng

    2016-11-14

    Compared with conventional radio frequency (RF) shielding methods in which the conductive coating material encloses the circuits design and the leakage problem occurs due to the gap in such conductive material, non-contact RF shielding at a distance is very promising but still impossible to achieve so far. In this paper, a multi-folded transformation optics method is proposed to design a non-contact device for RF shielding. This "open-shielded" device can shield any object at a distance from the electromagnetic waves at the operating frequency, while the object is still physically open to the outer space. Based on this, an open-carpet cloak is proposed and the functionality of the open-carpet cloak is demonstrated. Furthermore, we investigate a scheme of non-contact wave guiding to remotely control the propagation of surface waves over any obstacles. The flexibilities of such multi-folded transformation optics method demonstrate the powerfulness of the method in the design of novel remote devices with impressive new functionalities.

  15. Generalized stepwise demodulation transform and synchrosqueezing for time-frequency analysis and bearing fault diagnosis

    NASA Astrophysics Data System (ADS)

    Shi, Juanjuan; Liang, Ming; Necsulescu, Dan-Sorin; Guan, Yunpeng

    2016-04-01

    The energy concentration level is an important indicator for time-frequency analysis (TFA). Weak energy concentration would result in time-frequency representation (TFR) diffusion and thus leading to ambiguous results or even misleading signal analysis results, particularly for nonstationary multicomponent signals. To improve the energy concentration level, this paper proposes a generalized stepwise demodulation transform (GSDT). The rationale of the proposed method is that (1) the generalized demodulation (GD) can map the original signal into an analytic signal with constant instantaneous frequency (IF) and improve the energy concentration level on time-frequency plane, and (2) focusing on a short window around the time instant of interest, a backward demodulation operation can recover the original frequency at the time instant without affecting the improved energy concentration level. By repeating the backward demodulation at every time instant of interest, the TFR of the entire signal can be attained with enhanced energy concentration level. With the GSDT, an iterative GSDT (IGSDT) is developed to analyze multicomponent signal that is subjected to different modulating sources for their constituent components. The IGSDT iteratively demodulates each constituent component to attain its TFR and the TFR of the whole signal is derived from superposing all the resulting TFRs of constituent components. The cross-term free and more energy concentrated TFR of the signal is, therefore, obtained, and the diffusion in the TFR can be reduced. The GSDT-based synchrosqueezing transform is also elaborated to further enhance the GSDT(IGSDT) yielded TFR. The effectiveness of the proposed method in TFA is tested using both simulated monocomponent and multicomponent signals. The application of the proposed method to bearing fault detection is explored. Bearing condition and fault pattern can be revealed by the proposed method resulting TFR. The main advantages of the proposed method

  16. Linking the thermodynamic temperature to an optical frequency: recent advances in Doppler broadening thermometry

    PubMed Central

    2016-01-01

    Laser spectroscopy in the linear regime of radiation–matter interaction is a powerful tool for measuring thermodynamic quantities in a gas at thermodynamic equilibrium. In particular, the Doppler effect can be considered a gift of nature, linking the thermal energy to an optical frequency, namely the line centre frequency of an atomic or molecular spectral line. This is the basis of a relatively new method of primary gas thermometry, known as Doppler broadening thermometry (DBT). This paper reports on the efforts that have been carried out, in the last decade, worldwide, to the end of making DBT competitive with more consolidated and accurate methodologies, such as acoustic gas thermometry and dielectric constant gas thermometry. The main requirements for low-uncertainty DBT, of both theoretical and technical nature, will be discussed, with a special focus on those related to the line shape model and to the frequency scale. A deep comparison among the different molecules that have been selected in successful DBT implementations is also reported. Finally, for the first time, to the best of my knowledge, the influence of refractive index effects is discussed. PMID:26903093

  17. Linking the thermodynamic temperature to an optical frequency: recent advances in Doppler broadening thermometry.

    PubMed

    Gianfrani, Livio

    2016-03-28

    Laser spectroscopy in the linear regime of radiation-matter interaction is a powerful tool for measuring thermodynamic quantities in a gas at thermodynamic equilibrium. In particular, the Doppler effect can be considered a gift of nature, linking the thermal energy to an optical frequency, namely the line centre frequency of an atomic or molecular spectral line. This is the basis of a relatively new method of primary gas thermometry, known as Doppler broadening thermometry (DBT). This paper reports on the efforts that have been carried out, in the last decade, worldwide, to the end of making DBT competitive with more consolidated and accurate methodologies, such as acoustic gas thermometry and dielectric constant gas thermometry. The main requirements for low-uncertainty DBT, of both theoretical and technical nature, will be discussed, with a special focus on those related to the line shape model and to the frequency scale. A deep comparison among the different molecules that have been selected in successful DBT implementations is also reported. Finally, for the first time, to the best of my knowledge, the influence of refractive index effects is discussed.

  18. Gesture Frequency Linked Primarily to Story Length in 4-10-Year Old Children's Stories.

    PubMed

    Nicoladis, Elena; Marentette, Paula; Navarro, Samuel

    2016-04-01

    Previous studies have shown that older children gesture more while telling a story than younger children. This increase in gesture use has been attributed to increased story complexity. In adults, both narrative complexity and imagery predict gesture frequency. In this study, we tested the strength of three predictors of children's gesture use in a narrative context: age, narrative complexity (measured by discourse connectors), and use of imagery (measured by story length). French-, Spanish-, and English-speaking children between 4 and 10 years participated in this study. Including these three groups allows us to test for the generalizability of our results and for cross-linguistic differences in gesture frequency. All the children watched cartoons and retold the story. The results showed that the length of the story was a significant predictor of children's gesture rate while age and discourse connectors were not. There were no differences between language groups. One possible in interpretation of these results is that children's gesture frequency is strongly linked to activation of imagery.

  19. Linking transformational leadership to nurses' extra-role performance: the mediating role of self-efficacy and work engagement.

    PubMed

    Salanova, Marisa; Lorente, Laura; Chambel, Maria J; Martínez, Isabel M

    2011-10-01

    This paper is a report of a social cognitive theory-guided study about the link between supervisors' transformational leadership and staff nurses' extra-role performance as mediated by nurse self-efficacy and work engagement. Past research has acknowledged the positive influence that transformational leaders have on employee (extra-role) performance. However, less is known about the psychological mechanisms that may explain the links between transformational leaders and extra-role performance, which encompasses behaviours that are not considered formal job requirements, but which facilitate the smooth functioning of the organization as a social system. Seventeen supervisors evaluated nurses' extra-role performance, the data generating a sample consisting of 280 dyads. The nurses worked in different health services in a large Portuguese hospital and the participation rate was 76·9% for nurses and 100% for supervisors. Data were collected during 2009. A theory-driven model of the relationships between transformation leadership, self-efficacy, work engagement and nurses' extra-role performance was tested using Structural Equation Modelling. Data analysis revealed a full mediation model in which transformational leadership explained extra-role performance through self-efficacy and work engagement. A direct relationship between transformational leadership and work engagement was also found. Nurses' supervisors with a transformational leadership style enhance different 'extra-role' performance in nurses and this increases hospital efficacy. They do so by establishing a sense of self-efficacy but also by amplifying their levels of engagement in the workplace. © 2011 Blackwell Publishing Ltd.

  20. Power links with Ireland -- Excitation of turbine-generator shaft torsional vibrations by variable frequency currents superimposed on DC currents in asynchronous HVDC links

    SciTech Connect

    Hammons, T.J.; Tay, B.W.; Kok, K.L.

    1995-08-01

    The paper describes an in-depth analysis of excitation of shaft torsional vibrations in steam-turbine-generator-exciter shafts in close proximity to HVDC converter stations by variable-frequency ripple currents superimposed on the DC currents in asynchronous Links. It extends earlier work to include an in depth analysis of system scaling factors for harmonic currents impressed on generators in Northern Ireland by an inverter and to investigate the phenomena for possible torsional vibrations in the generators by the Link. Frequencies at which shaft torsional vibrations would be excited by modulation product harmonics in 50Hz/50Hz asynchronous Links as a function of deviation in system frequency is reviewed. Relative noncharacteristic current levels for 50Hz/50Hz connectors are illustrated assuming ripple currents at the inverter which gives realistic harmonic voltages in a twelve-pulse bridge. The paper then shows that torques in machines in multi-machine networks may be estimated by proportioning HVDC link harmonic disturbance current appropriately to each machine at risk. It is concluded that variable-frequency ripple currents superimposed on the DC current in asynchronous links can excite sympathetic torsional vibrations in turbine-generator-exciter shafts.

  1. Wavelet transform analysis to assess oscillations in pial artery pulsation at the human cardiac frequency.

    PubMed

    Winklewski, P J; Gruszecki, M; Wolf, J; Swierblewska, E; Kunicka, K; Wszedybyl-Winklewska, M; Guminski, W; Zabulewicz, J; Frydrychowski, A F; Bieniaszewski, L; Narkiewicz, K

    2015-05-01

    Pial artery adjustments to changes in blood pressure (BP) may last only seconds in humans. Using a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) in humans, we aimed to assess the relationship between spontaneous oscillations in BP and cc-TQ at frequencies between 0.5 Hz and 5 Hz. We hypothesized that analysis of very short data segments would enable the estimation of changes in the cardiac contribution to the BP vs. cc-TQ relationship during very rapid pial artery adjustments to external stimuli. BP and pial artery oscillations during baseline (70s and 10s signals) and the response to maximal breath-hold apnea were studied in eighteen healthy subjects. The cc-TQ was measured using NIR-T/BSS; cerebral blood flow velocity, the pulsatility index and the resistive index were measured using Doppler ultrasound of the left internal carotid artery; heart rate and beat-to-beat systolic and diastolic blood pressure were recorded using a Finometer; end-tidal CO2 was measured using a medical gas analyzer. Wavelet transform analysis was used to assess the relationship between BP and cc-TQ oscillations. The recordings lasting 10s and representing 10 cycles with a frequency of ~1 Hz provided sufficient accuracy with respect to wavelet coherence and wavelet phase coherence values and yielded similar results to those obtained from approximately 70cycles (70s). A slight but significant decrease in wavelet coherence between augmented BP and cc-TQ oscillations was observed by the end of apnea. Wavelet transform analysis can be used to assess the relationship between BP and cc-TQ oscillations at cardiac frequency using signals intervals as short as 10s. Apnea slightly decreases the contribution of cardiac activity to BP and cc-TQ oscillations.

  2. Length and refractive index measurement by Fourier transform interferometry and frequency comb spectroscopy

    NASA Astrophysics Data System (ADS)

    Balling, Petr; Mašika, Pavel; Křen, Petr; Doležal, Miroslav

    2012-09-01

    In this paper we describe the progress we have made in our simultaneous length measurement and the femtosecond comb interferometric spectroscopy in a conventional arrangement with a moving mirror. Scanning and detection over an interval longer than the distance between two consecutive pulses of the frequency comb allow for a spectral resolution of the individual frequency modes of the comb. Precise knowledge of comb mode frequency leads to a precise estimation of the spectral characteristics of inspected phenomena. Using the pulse train of the frequency comb allows for measurement with highly unbalanced lengths of interferometer arms, i.e. an absolute long distance measurement. Further, we present a non-contact (double sided) method of measurement of the length/thickness of plane-parallel objects (gauge blocks, glass samples) by combining the fs comb (white light) with single frequency laser interferometry. The position of a fringe packet is evaluated by estimating the stationary phase position for any wavelength in the spectral band used. The repeatability of this position estimation is a few nanometres regardless of whether dispersion of the arms is compensated (transform limited fringe packet ˜10 fringes FWHM) or highly different (fringe packet stretched to >200 fringes FWHM). The measurement of steel gauge block by this method was compared with the standard method, and deviation (+13 ± 12) nm for gauge blocks (2 to 100) mm was found. The measurement of low reflecting ceramic gauges or clear glass samples was also tested. In the case of glass, it becomes possible to measure simultaneously both the thickness and the refractive index (and dispersion) of flat samples.

  3. Measurement, comparison, and transformation of dynamic magnetization in pulse field and high-frequency alternating field

    NASA Astrophysics Data System (ADS)

    Kodama, K.

    2015-12-01

    Dynamic magnetizations of selected natural samples (sediments and volcanic rocks) were measured in time domain as well as in frequency domain. The time domain measurements were performed in pulse fields with variable lengths (10 μs to 10 ms) and amplitudes (0.5 mT to 0.7 T). To measure hysteresis parameters for small loops, one cycle of positive and negative pulses with different rate of field variation were generated. In the frequency domain, low-field magnetic susceptibility was measured over the frequency rage (1 kHz to 500 kHz) corresponding to the pulse lengths in the time domain measurements. Results in the time domain were characterized by the transient magnetization-field curves that were broadly comparable to the corresponding portions of the hysteresis loops measured by a quasi-static method using a VSM. The dynamic coercivity that is defined as the intersect with the abscissa in the negative regime increased as the pulse length reduced and the pulse peak increased. In strong pulse fields (> 0.5 T), irrespective of the kinds of samples, the magnetization remained at the end of a pulse and decayed exponentially within a few ms, suggesting rapid magnetic relaxations. In weak pulse fields, no such relaxation was observed except for the sediments rich in superparamagnetic (SP) particles. These field dependencies suggest that the relaxations in the strong fields could be due to the dynamics of the domain walls in the MD particles, while those of the sediments in weak fields may be ascribed to the relaxation of the SP particles. Results in the frequency domain were obtained in terms of the frequency spectrum of the real and imaginary components of complex susceptibility. Comparisons and interpretations of the data in these different domains were made in terms of the distribution of relaxation times. Discussions on the numerical conversion and transformation of these data as well as their rock magnetic applications will be provided.

  4. Links between the structure of an Antarctic shallow-water community and ice-scour frequency.

    PubMed

    Brown, Kirsty M; Fraser, Keiron P P; Barnes, David K A; Peck, Lloyd S

    2004-09-01

    Ice is a major structuring force in marine and freshwater environments at high latitudes. Although recovery from scouring has been quantified in time, the frequency of scouring in the Antarctic has not. We placed grids of markers at 9-17 m depth at two sites, to study ice-scouring over 2 years at Adelaide island (Antarctic Peninsula). We quantified the time scale of scour frequencies, and linked this to community mortality, age and diversity. Markers were hit from zero to at least three times in 2 years. At the least disturbed site (South Cove) 24% of markers were destroyed per year, whereas in North Cove 60% of markers were destroyed. There were significant differences in scouring frequency between our two sites: a given area in North Cove was on average hit twice as often as one in South Cove. Compared with near shore environments elsewhere, faunas of both sites were characteristic of high disturbance regimes, exhibiting low percent cover, diversity, ages and a high proportion of pioneers. Aspects of the encrusting communities studied reflected the differences between site disturbance regimes. North Cove was scoured twice as often, and bryozoan communities there had half the number of species, two-thirds the space occupation and twice the mortality level of those in South Cove. Maximum age in North Cove bryozoans was also half that in South Cove. Although there are natural disturbance events that rival ice-scouring in either frequency or catastrophic power at lower latitudes, none do both nor across such a wide depth range. We suggest that ice scour effects on polar benthos are even more significant than the same magnitude of disturbance at lower latitudes as recovery rates of high latitude communities are very slow. Climate warming seems likely to increase iceloading of near shore polar waters, so that some of the world's most intensely disturbed faunas may soon suffer even more disturbance.

  5. Agrobacterium-mediated high-frequency transformation of an elite commercial maize (Zea mays L.) inbred line.

    PubMed

    Cho, Myeong-Je; Wu, Emily; Kwan, Jackie; Yu, Maryanne; Banh, Jenny; Linn, Wutt; Anand, Ajith; Li, Zhi; TeRonde, Susan; Register, James C; Jones, Todd J; Zhao, Zuo-Yu

    2014-10-01

    An improved Agrobacterium -mediated transformation protocol is described for a recalcitrant commercial maize elite inbred with optimized media modifications and AGL1. These improvements can be applied to other commercial inbreds. This study describes a significantly improved Agrobacterium-mediated transformation protocol in a recalcitrant commercial maize elite inbred, PHR03, using optimal co-cultivation, resting and selection media. The use of green regenerative tissue medium components, high copper and 6-benzylaminopurine, in resting and selection media dramatically increased the transformation frequency. The use of glucose in resting medium further increased transformation frequency by improving the tissue induction rate, tissue survival and tissue proliferation from immature embryos. Consequently, an optimal combination of glucose, copper and cytokinin in the co-cultivation, resting and selection media resulted in significant improvement from 2.6 % up to tenfold at the T0 plant level using Agrobacterium strain LBA4404 in transformation of PHR03. Furthermore, we evaluated four different Agrobacterium strains, LBA4404, AGL1, EHA105, and GV3101 for transformation frequency and event quality. AGL1 had the highest transformation frequency with up to 57.1 % at the T0 plant level. However, AGL1 resulted in lower quality events (defined as single copy for transgenes without Agrobacterium T-DNA backbone) when compared to LBA4404 (30.1 vs 25.6 %). We propose that these improvements can be applied to other recalcitrant commercial maize inbreds.

  6. Novel high-frequency, high-power, pulsed oscillator based on a transmission line transformer.

    PubMed

    Burdt, R; Curry, R D

    2007-07-01

    Recent analysis and experiments have demonstrated the potential for transmission line transformers to be employed as compact, high-frequency, high-power, pulsed oscillators with variable rise time, high output impedance, and high operating efficiency. A prototype system was fabricated and tested that generates a damped sinusoidal wave form at a center frequency of 4 MHz into a 200 Omega load, with operating efficiency above 90% and peak power on the order of 10 MW. The initial rise time of the pulse is variable and two experiments were conducted to demonstrate initial rise times of 12 and 3 ns, corresponding to a spectral content from 4-30 and from 4-100 MHz, respectively. A SPICE model has been developed to accurately predict the circuit behavior and scaling laws have been identified to allow for circuit design at higher frequencies and higher peak power. The applications, circuit analysis, test stand, experimental results, circuit modeling, and design of future systems are all discussed.

  7. Frequency Clustering Analysis for Resting State Functional Magnetic Resonance Imaging Based on Hilbert-Huang Transform

    PubMed Central

    Wu, Xia; Wu, Tong; Liu, Chenghua; Wen, Xiaotong; Yao, Li

    2017-01-01

    Objective: Exploring resting-state functional networks using functional magnetic resonance imaging (fMRI) is a hot topic in the field of brain functions. Previous studies suggested that the frequency dependence between blood oxygen level dependent (BOLD) signals may convey meaningful information regarding interactions between brain regions. Methods: In this article, we introduced a novel frequency clustering analysis method based on Hilbert-Huang Transform (HHT) and a label-replacement procedure. First, the time series from multiple predefined regions of interest (ROIs) were extracted. Second, each time series was decomposed into several intrinsic mode functions (IMFs) by using HHT. Third, the improved k-means clustering method using a label-replacement method was applied to the data of each subject to classify the ROIs into different classes. Results: Two independent resting-state fMRI dataset of healthy subjects were analyzed to test the efficacy of method. The results show almost identical clusters when applied to different runs of a dataset or to different datasets, indicating a stable performance of our framework. Conclusions and Significance: Our framework provided a novel measure for functional segregation of the brain according to time-frequency characteristics of resting state BOLD activities. PMID:28261074

  8. Effect of soil temperature on optical frequency transfer through unidirectional dense-wavelength-division-multiplexing fiber-optic links.

    PubMed

    Pinkert, T J; Böll, O; Willmann, L; Jansen, G S M; Dijck, E A; Groeneveld, B G H M; Smets, R; Bosveld, F C; Ubachs, W; Jungmann, K; Eikema, K S E; Koelemeij, J C J

    2015-02-01

    Results of optical frequency transfer over a carrier-grade dense-wavelength-division-multiplexing (DWDM) optical fiber network are presented. The relation between soil temperature changes on a buried optical fiber and frequency changes of an optical carrier through the fiber is modeled. Soil temperatures, measured at various depths by the Royal Netherlands Meteorology Institute (KNMI) are compared with observed frequency variations through this model. A comparison of a nine-day record of optical frequency measurements through the 2×298  km fiber link with soil temperature data shows qualitative agreement. A soil temperature model is used to predict the link stability over longer periods (days-months-years). We show that optical frequency dissemination is sufficiently stable to distribute and compare, e.g., rubidium frequency standards over standard DWDM optical fiber networks using unidirectional fibers.

  9. The space-math link in preschool boys and girls: Importance of mental transformation, targeting accuracy, and spatial anxiety.

    PubMed

    Wong, Wang I

    2017-06-01

    Spatial abilities are pertinent to mathematical competence, but evidence of the space-math link has largely been confined to older samples and intrinsic spatial abilities (e.g., mental transformation). The roles of gender and affective factors are also unclear. This study examined the correlations between counting ability, mental transformation, and targeting accuracy in 182 Hong Kong preschoolers, and whether these relationships were weaker at higher spatial anxiety levels. Both spatial abilities related with counting similarly for boys and girls. Targeting accuracy also mediated the male advantage in counting. Interestingly, spatial anxiety moderated the space-math links, but differently for boys and girls. For boys, spatial abilities were irrelevant to counting at high anxiety levels; for girls, the role of anxiety on the space-math link is less clear. Results extend the evidence base of the space-math link to include an extrinsic spatial ability (targeting accuracy) and have implications for intervention programmes. Statement of contribution What is already known on this subject? Much evidence of a space-math link in adolescent and adult samples and for intrinsic spatial abilities. What does this study add? Extended the space-math link to include both intrinsic and extrinsic spatial abilities in a preschool sample. Showed how spatial anxiety moderated the space-math link differently for boys and girls. © 2016 The British Psychological Society.

  10. Performance testing of a high frequency link converter for Space Station power distribution system

    NASA Technical Reports Server (NTRS)

    Sul, S. K.; Alan, I.; Lipo, T. A.

    1989-01-01

    The testing of a brassboard version of a 20-kHz high-frequency ac voltage link prototype converter dynamics for Space Station application is presented. The converter is based on a three-phase six-pulse bridge concept. The testing includes details of the operation of the converter when it is driving an induction machine source/load. By adapting a field orientation controller (FOC) to the converter, four-quadrant operation of the induction machine from the converter has been achieved. Circuit modifications carried out to improve the performance of the converter are described. The performance of two 400-Hz induction machines powered by the converter with simple V/f regulation mode is reported. The testing and performance results for the converter utilizing the FOC, which provides the capability for rapid torque changes, speed reversal, and four-quadrant operation, are reported.

  11. Ultrasonic frequency analysis of antibody-linked hydrogel biosensors for rapid point of care testing.

    PubMed

    Dion, Jonathan R; Burns, David H

    2011-02-15

    Analyte quantification in highly scattering media such as tissue, blood, and other biological fluids is challenging using conventional spectroscopic methods. Ultrasound easily penetrates these opaque samples, yet currently provides little chemical information. We have developed a general approach for creating hydrogel biosensors based on antibody-linked cellulose polymers. Target recognition induces changes to the sensor stiffness and size, which is accompanied by characteristic changes to a measured ultrasonic frequency profile. Using this technique, nM sensitivity for acetaminophen is demonstrated in a series of biofluids including whole blood, blood plasma, saliva, and urine. Likewise, this methodology is attractive for point of care diagnostics due to the short measurement time, simple methodology which excludes pretreatment of samples, and has minimal chemical or buffer requirements. Copyright © 2010 Elsevier B.V. All rights reserved.

  12. Inference of population structure using multilocus genotype data: linked loci and correlated allele frequencies.

    PubMed Central

    Falush, Daniel; Stephens, Matthew; Pritchard, Jonathan K

    2003-01-01

    We describe extensions to the method of Pritchard et al. for inferring population structure from multilocus genotype data. Most importantly, we develop methods that allow for linkage between loci. The new model accounts for the correlations between linked loci that arise in admixed populations ("admixture linkage disequilibium"). This modification has several advantages, allowing (1) detection of admixture events farther back into the past, (2) inference of the population of origin of chromosomal regions, and (3) more accurate estimates of statistical uncertainty when linked loci are used. It is also of potential use for admixture mapping. In addition, we describe a new prior model for the allele frequencies within each population, which allows identification of subtle population subdivisions that were not detectable using the existing method. We present results applying the new methods to study admixture in African-Americans, recombination in Helicobacter pylori, and drift in populations of Drosophila melanogaster. The methods are implemented in a program, structure, version 2.0, which is available at http://pritch.bsd.uchicago.edu. PMID:12930761

  13. Carrier phase recovery performance for PN-spread TDRSS link with radio-frequency interference

    NASA Technical Reports Server (NTRS)

    Mckenzie, T. M.; Braun, W. R.

    1979-01-01

    The carrier-phase recovery performance of a Costas loop for a nonlinear satellite channel with uplink and downlink noise is analyzed, and the extension of these results to the case where uplink radio-frequency interference (RFI) is present is considered. The signal format here is binary phase-shift-keyed (BPSK) or unbalanced quaternary phase-shift-keyed (UQPSK), the signals being either the non-return-to-zero (NRZ) or biphase (Manchester) type. With UQPSK, at least one data stream must be PN-spread. The channel comprises additive white Gaussian noise (WGN), a wideband filter, a bandpass nonlinearity and more additive WGN. The RFI being considered is pulsed continuous-wave, pulsed WGN, or a combination of the two. It is noted that the Tracking and Data Relay Satellite System (TDRSS) will be subjected to RFI from certain locations, especially in the S-band of frequencies. The characteristics of this link are generalized to form the assumptions underlying this analysis. The analytical results given include the S-curve of the equivalent loop and the phase-error variance of the linearized loop.

  14. Obesity-Linked Homologues TfAP-2 and Twz Establish Meal Frequency in Drosophila melanogaster

    PubMed Central

    Williams, Michael J.; Goergen, Philip; Rajendran, Jayasimman; Zheleznyakova, Galina; Hägglund, Maria G.; Perland, Emelie; Bagchi, Sonchita; Kalogeropoulou, Argyro; Khan, Zaid; Fredriksson, Robert; Schiöth, Helgi B.

    2014-01-01

    In all animals managing the size of individual meals and frequency of feeding is crucial for metabolic homeostasis. In the current study we demonstrate that the noradrenalin analogue octopamine and the cholecystokinin (CCK) homologue Drosulfakinin (Dsk) function downstream of TfAP-2 and Tiwaz (Twz) to control the number of meals in adult flies. Loss of TfAP-2 or Twz in octopaminergic neurons increased the size of individual meals, while overexpression of TfAP-2 significantly decreased meal size and increased feeding frequency. Of note, our study reveals that TfAP-2 and Twz regulate octopamine signaling to initiate feeding; then octopamine, in a negative feedback loop, induces expression of Dsk to inhibit consummatory behavior. Intriguingly, we found that the mouse TfAP-2 and Twz homologues, AP-2β and Kctd15, co-localize in areas of the brain known to regulate feeding behavior and reward, and a proximity ligation assay (PLA) demonstrated that AP-2β and Kctd15 interact directly in a mouse hypothalamus-derived cell line. Finally, we show that in this mouse hypothalamic cell line AP-2β and Kctd15 directly interact with Ube2i, a mouse sumoylation enzyme, and that AP-2β may itself be sumoylated. Our study reveals how two obesity-linked homologues regulate metabolic homeostasis by modulating consummatory behavior. PMID:25187989

  15. Vector frequency-comb Fourier-transform spectroscopy for characterizing metamaterials

    NASA Astrophysics Data System (ADS)

    Ganz, T.; Brehm, M.; von Ribbeck, H. G.; van der Weide, D. W.; Keilmann, F.

    2008-12-01

    We determine infrared transmission amplitude and phase spectra of metamaterial samples at well-defined incidence and polarization with a vector ('asymmetric') frequency-comb Fourier-transform spectrometer (c-FTS) that uses no moving elements. The metamaterials are free-standing metallic hole arrays; we study their resonances in the 7-13 μm and 100-1000 μm wavelength regions due both to interaction with bulk waves (Wood anomaly) and with leaky surface plasmon polaritons (near-unity transmittance, coupling features and dispersion). Such complex-valued transmission and reflection spectra could be used to compute a metamaterial's complex dielectric function directly, as well as its magnetic and magneto-optical permeability functions.

  16. Recognition of Frequency Modulated Whistle-Like Sounds by a Bottlenose Dolphin (Tursiops truncatus) and Humans with Transformations in Amplitude, Duration and Frequency

    PubMed Central

    Branstetter, Brian K.; DeLong, Caroline M.; Dziedzic, Brandon; Black, Amy; Bakhtiari, Kimberly

    2016-01-01

    Bottlenose dolphins (Tursiops truncatus) use the frequency contour of whistles produced by conspecifics for individual recognition. Here we tested a bottlenose dolphin’s (Tursiops truncatus) ability to recognize frequency modulated whistle-like sounds using a three alternative matching-to-sample paradigm. The dolphin was first trained to select a specific object (object A) in response to a specific sound (sound A) for a total of three object-sound associations. The sounds were then transformed by amplitude, duration, or frequency transposition while still preserving the frequency contour of each sound. For comparison purposes, 30 human participants completed an identical task with the same sounds, objects, and training procedure. The dolphin’s ability to correctly match objects to sounds was robust to changes in amplitude with only a minor decrement in performance for short durations. The dolphin failed to recognize sounds that were frequency transposed by plus or minus ½ octaves. Human participants demonstrated robust recognition with all acoustic transformations. The results indicate that this dolphin’s acoustic recognition of whistle-like sounds was constrained by absolute pitch. Unlike human speech, which varies considerably in average frequency, signature whistles are relatively stable in frequency, which may have selected for a whistle recognition system invariant to frequency transposition. PMID:26863519

  17. Extremely low-frequency magnetic fields of transformers and possible biological and health effects.

    PubMed

    Sirav, Bahriye; Sezgin, Gaye; Seyhan, Nesrin

    2014-12-01

    Physiological processes in organisms can be influenced by extremely low-frequency (ELF) electromagnetic energy. Biological effect studies have great importance; as well as measurement studies since they provide information on the real exposure situations. In this study, the leakage magnetic fields around a transformer were measured in an apartment building in Küçükçekmece, Istanbul, and the measurement results were evaluated with respect to the international exposure standards. The transformer station was on the bottom floor of a three-floor building. It was found that people living and working in the building were exposed to ELF magnetic fields higher than the threshold magnetic field value of the International Agency for Research on Cancer (IARC). Many people living in this building reported health complaints such as immunological problems of their children. There were child-workers working in the textile factories located in the building. Safe distances or areas for these people should be recommended. Protective measures could be implemented to minimize these exposures. Further residential exposure studies are needed to demonstrate the exposure levels of ELF magnetic fields. Precautions should, therefore, be taken either to reduce leakage or minimize the exposed fields. Shielding techniques should be used to minimize the leakage magnetic fields in such cases.

  18. Testing the associative-link hypothesis in immediate serial recall: Evidence from word frequency and word imageability effects.

    PubMed

    Tse, Chi-Shing; Altarriba, Jeanette

    2007-08-01

    Two immediate serial recall experiments were conducted to test the associative-link hypothesis (Stuart & Hulme, 2000). We manipulated interitem association by varying the intralist latent semantic analysis (LSA) cosines in our 7-item study word lists, each of which consists of high- or low-frequency words in Experiment 1 and high- or low-imageability words in Experiment 2. Whether item recall performance was scored by a serial-recall or free-recall criterion, we found main effects of interitem association, word imageability, and word frequency. The effect of interitem association also interacted with the word frequency effect, but not with the word imageability effect. The LSA-cosinexword frequency interaction occurred in the recency, but not primacy, portion of the serial position curve. The present findings set explanatory boundaries for the associative-link hypothesis and we argue that both item- and associative-based mechanisms are necessary to account for the word frequency effect in immediate serial recall.

  19. Word frequency effects in immediate serial recall of pure and mixed lists: tests of the associative link hypothesis.

    PubMed

    Saint-Aubin, Jean; LeBlanc, Jacinthe

    2005-12-01

    In immediate serial recall, high-frequency words are better recalled than low-frequency words. Recently, it has been suggested that high-frequency words are better recalled because of their better long-term associative links, and not because of the intrinsic properties of their long-term representations. In the experiment reported here, recall performance was compared for pure lists of high- and low-frequency words, and for mixed lists composed of either one low- and five high-frequency words or the reverse. The usual advantage of high-frequency words was found with pure lists and this advantage was reduced, but still significant with mixed lists composed of five low-frequency words. However, the low-frequency word included in a high-frequency list was recalled just as well as high-frequency words. Results are challenging for the associative link hypothesis and are best interpreted within an item-based reconstruction hypothesis, along with a distinctiveness account.

  20. Arsenicals Produce Stable Progressive Changes in DNA Methylation Patterns that are Linked to Malignant Transformation of Immortalized Urothelial Cells

    PubMed Central

    Jensen, Taylor J.; Novak, Petr; Wnek, Shawn M.; Gandolfi, A. Jay; Futscher, Bernard W.

    2009-01-01

    Aberrant DNA methylation participates in carcinogenesis and is a molecular hallmark of a tumor cell. Tumor cells generally exhibit a redistribution of DNA methylation resulting in global hypomethylation with regional hypermethylation; however, the speed in which these changes emerge has not been fully elucidated and may depend on the temporal location of the cell in the path from normal, finite lifespan to malignant transformation. We used a model of arsenical-induced malignant transformation of immortalized human urothelial cells and DNA methylation microarrays to examine the extent and temporal nature of changes in DNA methylation that occur during the transition from immortal to malignantly transformed. Our data presented herein suggest that during arsenical-induced malignant transformation, aberrant DNA methylation occurs non-randomly, progresses gradually at hundreds of gene promoters, alters expression of the associated gene, and these changes are coincident with the acquisition of malignant properties, such as anchorage independent growth and tumor formation in immunocompromised mice. The DNA methylation changes appear stable, since malignantly transformed cells removed from the transforming arsenical exhibited no reversion in DNA methylation levels, associated gene expression, or malignant phenotype. These data suggest that arsenicals act as epimutagens and directly link their ability to induce malignant transformation to their actions on the epigenome. PMID:19716837

  1. Arsenicals produce stable progressive changes in DNA methylation patterns that are linked to malignant transformation of immortalized urothelial cells

    SciTech Connect

    Jensen, Taylor J.; Novak, Petr; Wnek, Shawn M.; Gandolfi, A. Jay; Futscher, Bernard W.

    2009-12-01

    Aberrant DNA methylation participates in carcinogenesis and is a molecular hallmark of a tumor cell. Tumor cells generally exhibit a redistribution of DNA methylation resulting in global hypomethylation with regional hypermethylation; however, the speed in which these changes emerge has not been fully elucidated and may depend on the temporal location of the cell in the path from normal, finite lifespan to malignant transformation. We used a model of arsenical-induced malignant transformation of immortalized human urothelial cells and DNA methylation microarrays to examine the extent and temporal nature of changes in DNA methylation that occur during the transition from immortal to malignantly transformed. Our data presented herein suggest that during arsenical-induced malignant transformation, aberrant DNA methylation occurs non-randomly, progresses gradually at hundreds of gene promoters, and alters expression of the associated gene, and these changes are coincident with the acquisition of malignant properties, such as anchorage independent growth and tumor formation in immunocompromised mice. The DNA methylation changes appear stable, since malignantly transformed cells removed from the transforming arsenical exhibited no reversion in DNA methylation levels, associated gene expression, or malignant phenotype. These data suggest that arsenicals act as epimutagens and directly link their ability to induce malignant transformation to their actions on the epigenome.

  2. Scaling Laws and Frequency Decomposition from Wavelet Transform Maxima Lines and Ridges

    NASA Astrophysics Data System (ADS)

    Haase, M.; Widjajakusuma, J.; Bader, R.

    Wavelet techniques have now become well established for various applications. They are especially attractive for a reliable characterization of the scaling behaviour of functions and measures with non-oscillating singularities. Another important feature of wavelets is their ability to decompose vibrations into components according to their instantaneous frequencies. The essential information about scaling and instantaneous frequencies is contained in a small subset of the redundant continuous wavelet transform, namely in the maxima lines and ridges, which can be considered as a fingerprint of the signal. We show that even oscillating singularities can be easily characterized using complex progessive wavelets. We derive differential equations for two families of wavelets which allow a direct numerical integration of maxima lines and ridges. The applications presented range from fractal basin boundaries, oscillating singularities, system identification in engineering structures and design to a problem in musicology. Wavelets are used to characterize the timbre of instruments. The fine structure of transients allow an identification of instruments and instrument classes.

  3. Superconducting multiturn flux transformers for radio frequency superconducting quantum interference devices

    NASA Astrophysics Data System (ADS)

    Yi, H. R.; Zhang, Y.; Schubert, J.; Zander, W.; Zeng, X. H.; Klein, N.

    2000-11-01

    This article describes three planar layouts of superconducting multiturn flux transformers integrated with a coplanar resonator for radio frequency (rf) superconducting quantum interference device (SQUID) magnetometers. The best magnetic field noise values of 22 and 11.5 fT/Hz1/2 in the white noise regime were obtained for the layout with two input coils and the layout with the labyrinth resonator, respectively. Excess low-frequency noise (about 200 fT/Hz1/2 at 10 Hz) was present. Computer simulation showed that the loss in this trilayer system was dominated by the high loss tangent of the dielectric film used for the separation of the upper and lower superconducting films. The rf coupling coefficient krf between the resonator and the flip-chip-coupled SQUID was also estimated. The values krf2≈14×10-3 obtained for the layout with two input coils, and krf2≈45×10-3 for the layout with the labyrinth resonator were considerably higher than the typical value of krf2≈7×10-3 for the single-layer coplanar resonator. These high coupling coefficients have compensated the somewhat degraded unloaded quality factor of the resonator, thus securing the optimum operation of the rf SQUID.

  4. Improving the sensitivity of a high-Tc SQUID at MHz frequency using a normal metal transformer

    NASA Astrophysics Data System (ADS)

    He, D. F.; Itozaki, H.; Tachiki, M.

    2006-05-01

    Superconducting quantum interference devices (SQUIDs) can be used to detect the signals of nuclear quadrupole resonance (NQR). The NQR frequencies of some interesting materials are in the order of MHz. However, the sensitivity of a high-Tc SQUID is normally not enough to detect the weak NQR signals. To improve the sensitivity of a high-Tc SQUID at MHz frequency, we used a transformer made of normal copper wire. The transformer was composed of a pickup coil, an input coil and a capacitor. The pickup coil was used to detect the magnetic field; the input coil was used to couple the field to the SQUID; and the capacitor was used to create a resonant frequency. By using the normal metal transformer, the magnetic field resolution of the high-Tc dc SQUID was improved by about 38.8 times (from 220 to 5.67 fT Hz-1/2) at 954 kHz.

  5. Linking high-frequency DOC dynamics to the age of connected water sources

    NASA Astrophysics Data System (ADS)

    Tunaley, C.; Tetzlaff, D.; Lessels, J.; Soulsby, C.

    2016-07-01

    We combined high-frequency dissolved organic matter fluorescence (FDOM) data with stable isotope observations to identify the sources and ages of runoff that cause temporal variability in dissolved organic carbon (DOC) within a peat-dominated Scottish catchment. FDOM was strongly correlated (r2 ˜ 0.8) with DOC, allowing inference of a 15 min time series. We captured 34 events over a range of hydrological conditions. Along with marked seasonality, different event responses were observed during summer depending on dry or wet antecedent conditions. The majority of events exhibited anticlockwise hysteresis as a result of the expansion of the riparian saturation zone, mobilizing previously unconnected DOC sources. Water ages from the main runoff sources were extracted from a tracer-aided hydrological model. Particularly useful were ages of overland flow, which were negatively correlated with DOC concentration. Overland flow age, which ranged between 0.2 and 360 days, reflected antecedent conditions, with younger water generally mobilizing the highest DOC concentrations in summer events. During small events with dry antecedent conditions, DOC response was proportionally higher due to the displacement and mixing of small volumes of previously unconnected highly concentrated riparian soil waters by new precipitation. During large events with wet antecedent conditions, the riparian saturation zone expands to organic layers on the hillslopes causing peaks in DOC. However, these peaks were limited by dilution and supply. This study highlights the utility of linking high-frequency DOC measurements with other tracers, allowing the effects of hydrologic connectivity and antecedent conditions on delivery of DOC to streams to be assessed.

  6. Transformer modeling for low- and mid-frequency electromagnetic transients simulation

    NASA Astrophysics Data System (ADS)

    Lambert, Mathieu

    In this work, new models are developed for single-phase and three-phase shell-type transformers for the simulation of low-frequency transients, with the use of the coupled leakage model. This approach has the advantage that it avoids the use of fictitious windings to connect the leakage model to a topological core model, while giving the same response in short-circuit as the indefinite admittance matrix (BCTRAN) model. To further increase the model sophistication, it is proposed to divide windings into coils in the new models. However, short-circuit measurements between coils are never available. Therefore, a novel analytical method is elaborated for this purpose, which allows the calculation in 2-D of short-circuit inductances between coils of rectangular cross-section. The results of this new method are in agreement with the results obtained from the finite element method in 2-D. Furthermore, the assumption that the leakage field is approximately 2-D in shell-type transformers is validated with a 3-D simulation. The outcome of this method is used to calculate the self and mutual inductances between the coils of the coupled leakage model and the results are showing good correspondence with terminal short-circuit measurements. Typically, leakage inductances in transformers are calculated from short-circuit measurements and the magnetizing branch is calculated from no-load measurements, assuming that leakages are unimportant for the unloaded transformer and that magnetizing current is negligible during a short-circuit. While the core is assumed to have an infinite permeability to calculate short-circuit inductances, and it is a reasonable assumption since the core's magnetomotive force is negligible during a short-circuit, the same reasoning does not necessarily hold true for leakage fluxes in no-load conditions. This is because the core starts to saturate when the transformer is unloaded. To take this into account, a new analytical method is developed in this

  7. Planar-waveguide external cavity laser stabilization for an optical link with 10(-19) frequency stability.

    PubMed

    Clivati, Cecilia; Mura, Alberto; Calonico, Davide; Levi, Filippo; Costanzo, Giovanni A; Calosso, Claudio E; Godone, Aldo

    2011-12-01

    We stabilized the frequency of a compact planar-waveguide external cavity laser (ECL) on a Fabry-Perot cavity (FPC) through a Pound-Drever-Hall scheme. The residual frequency stability of the ECL is 10(-14), comparable to the stability achievable with a fiber laser (FL) locked to an FPC through the same scheme. We set up an optical link of 100 km, based on fiber spools, that reaches 10(-19) relative stability, and we show that its performances using the ECL or FL are comparable. Thus ECLs could serve as an excellent replacement for FLs in optical links where cost-effectiveness and robustness are important considerations.

  8. Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

    DOEpatents

    Pitel, I.J.

    1987-02-03

    The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage. 19 figs.

  9. Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

    DOEpatents

    Pitel, Ira J.

    1987-02-03

    The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage.

  10. HTLV-1 tax stabilizes MCL-1 via TRAF6-dependent K63-linked polyubiquitination to promote cell survival and transformation.

    PubMed

    Choi, Young Bong; Harhaj, Edward William

    2014-10-01

    The human T-cell leukemia virus type 1 (HTLV-1) Tax protein hijacks the host ubiquitin machinery to activate IκB kinases (IKKs) and NF-κB and promote cell survival; however, the key ubiquitinated factors downstream of Tax involved in cell transformation are unknown. Using mass spectrometry, we undertook an unbiased proteome-wide quantitative survey of cellular proteins modified by ubiquitin in the presence of Tax or a Tax mutant impaired in IKK activation. Tax induced the ubiquitination of 22 cellular proteins, including the anti-apoptotic BCL-2 family member MCL-1, in an IKK-dependent manner. Tax was found to promote the nondegradative lysine 63 (K63)-linked polyubiquitination of MCL-1 that was dependent on the E3 ubiquitin ligase TRAF6 and the IKK complex. Tax interacted with and activated TRAF6, and triggered its mitochondrial localization, where it conjugated four carboxyl-terminal lysine residues of MCL-1 with K63-linked polyubiquitin chains, which stabilized and protected MCL-1 from genotoxic stress-induced degradation. TRAF6 and MCL-1 played essential roles in the survival of HTLV-1 transformed cells and the immortalization of primary T cells by HTLV-1. Therefore, K63-linked polyubiquitination represents a novel regulatory mechanism controlling MCL-1 stability that has been usurped by a viral oncogene to precipitate cell survival and transformation.

  11. High resolution frequency to time domain transformations applied to the stepped carrier MRIS measurements

    NASA Technical Reports Server (NTRS)

    Ardalan, Sasan H.

    1992-01-01

    Two narrow-band radar systems are developed for high resolution target range estimation in inhomogeneous media. They are reformulations of two presently existing systems such that high resolution target range estimates may be achieved despite the use of narrow bandwidth radar pulses. A double sideband suppressed carrier radar technique originally derived in 1962, and later abandoned due to its inability to accurately measure target range in the presence of an interfering reflection, is rederived to incorporate the presence of an interfering reflection. The new derivation shows that the interfering reflection causes a period perturbation in the measured phase response. A high resolution spectral estimation technique is used to extract the period of this perturbation leading to accurate target range estimates independent of the signal-to-interference ratio. A non-linear optimal signal processing algorithm is derived for a frequency-stepped continuous wave radar system. The resolution enhancement offered by optimal signal processing of the data over the conventional Fourier Transform technique is clearly demonstrated using measured radar data. A method for modeling plane wave propagation in inhomogeneous media based on transmission line theory is derived and studied. Several simulation results including measurement of non-uniform electron plasma densities that develop near the heat tiles of a space re-entry vehicle are presented which verify the validity of the model.

  12. Linking Transformational Materials and Processing for an Energy-Efficient and Low-Carbon Economy, 2010

    SciTech Connect

    Hunt, Warren H.; Brindle, Ross; James, Mallory; Justiniano, Mauricio; Sabouni, Ridah; Seader, Melanie; Ruch, Jennifer; Andres, Howard; Zafar, Muhammad

    2010-06-01

    The Energy Materials Blue Ribbon Panel, representing experts from industry, academia, and government, identifies new materials and processing breakthroughs that could lead to transformational advances in energy efficiency, energy security, and carbon reduction.

  13. Definitions of non-stationary vibration power for time-frequency analysis and computational algorithms based upon harmonic wavelet transform

    NASA Astrophysics Data System (ADS)

    Heo, YongHwa; Kim, Kwang-joon

    2015-02-01

    While the vibration power for a set of harmonic force and velocity signals is well defined and known, it is not as popular yet for a set of stationary random force and velocity processes, although it can be found in some literatures. In this paper, the definition of the vibration power for a set of non-stationary random force and velocity signals will be derived for the purpose of a time-frequency analysis based on the definitions of the vibration power for the harmonic and stationary random signals. The non-stationary vibration power, defined as the short-time average of the product of the force and velocity over a given frequency range of interest, can be calculated by three methods: the Wigner-Ville distribution, the short-time Fourier transform, and the harmonic wavelet transform. The latter method is selected in this paper because band-pass filtering can be done without phase distortions, and the frequency ranges can be chosen very flexibly for the time-frequency analysis. Three algorithms for the time-frequency analysis of the non-stationary vibration power using the harmonic wavelet transform are discussed. The first is an algorithm for computation according to the full definition, while the others are approximate. Noting that the force and velocity decomposed into frequency ranges of interest by the harmonic wavelet transform are constructed with coefficients and basis functions, for the second algorithm, it is suggested to prepare a table of time integrals of the product of the basis functions in advance, which are independent of the signals under analysis. How to prepare and utilize the integral table are presented. The third algorithm is based on an evolutionary spectrum. Applications of the algorithms to the time-frequency analysis of the vibration power transmitted from an excitation source to a receiver structure in a simple mechanical system consisting of a cantilever beam and a reaction wheel are presented for illustration.

  14. MATHEMATICAL MODELS FOR SOME RADIO-FREQUENCY TRANSMISSION-LINE TRANSFORMERS

    DTIC Science & Technology

    MATRICES(MATHEMATICS), *PHASE SHIFT CIRCUITS, *RADIOFREQUENCY, *TRANSFORMERS, *TRANSMISSION LINES, BROADBAND, DIELECTRIC PROPERTIES, ELECTRICAL IMPEDANCE, FERRITES, IMPEDANCE MATCHING , MATHEMATICAL ANALYSIS.

  15. Wavelet Transform for Time-Frequency Analysis of the Vibrational Signature and its Application

    DTIC Science & Technology

    1993-08-17

    Wavelet transform is applied to the analysis of vibration signatures in order to verify the ability of the detection of abnormal condition. It can...first stage. The objective of this report outlines the definition of the wavelet transform and is to discuss the properties of the wavelet transform as

  16. TRANSFORMATION

    SciTech Connect

    LACKS,S.A.

    2003-10-09

    Transformation, which alters the genetic makeup of an individual, is a concept that intrigues the human imagination. In Streptococcus pneumoniae such transformation was first demonstrated. Perhaps our fascination with genetics derived from our ancestors observing their own progeny, with its retention and assortment of parental traits, but such interest must have been accelerated after the dawn of agriculture. It was in pea plants that Gregor Mendel in the late 1800s examined inherited traits and found them to be determined by physical elements, or genes, passed from parents to progeny. In our day, the material basis of these genetic determinants was revealed to be DNA by the lowly bacteria, in particular, the pneumococcus. For this species, transformation by free DNA is a sexual process that enables cells to sport new combinations of genes and traits. Genetic transformation of the type found in S. pneumoniae occurs naturally in many species of bacteria (70), but, initially only a few other transformable species were found, namely, Haemophilus influenzae, Neisseria meningitides, Neisseria gonorrheae, and Bacillus subtilis (96). Natural transformation, which requires a set of genes evolved for the purpose, contrasts with artificial transformation, which is accomplished by shocking cells either electrically, as in electroporation, or by ionic and temperature shifts. Although such artificial treatments can introduce very small amounts of DNA into virtually any type of cell, the amounts introduced by natural transformation are a million-fold greater, and S. pneumoniae can take up as much as 10% of its cellular DNA content (40).

  17. Transformation of the frequency-modulated continuous-wave field into a train of short pulses by resonant filters

    NASA Astrophysics Data System (ADS)

    Shakhmuratov, R. N.

    2017-03-01

    The resonant filtering method transforming the frequency-modulated radiation field into a train of short pulses is proposed to be applied in the optical domain. Effective frequency modulation can be achieved by using an electro-optic modulator. Due to frequency modulation, a narrow-spectrum cw radiation field is seen by the resonant filter as a comb of equidistant spectral components separated by the modulation frequency. Tuning a narrow-bandwidth filter in resonance with the n th spectral component of the comb transforms the radiation field into bunches of pulses, with n pulses in each bunch. The transformation is explained by the interference of the coherently scattered resonant component of the field with the whole comb. Constructive interference results in the formation of pulses, while destructive interference is seen as dark windows between pulses. It is indicated that the optimal thickness of the resonant filter is several orders of magnitude smaller than the necessary thickness of the dispersive filters used before in the optical domain to produce short pulses from the frequency-modulated field.

  18. TRANSFORMER

    DOEpatents

    Baker, W.R.

    1959-08-25

    Transformers of a type adapted for use with extreme high power vacuum tubes where current requirements may be of the order of 2,000 to 200,000 amperes are described. The transformer casing has the form of a re-entrant section being extended through an opening in one end of the cylinder to form a coaxial terminal arrangement. A toroidal multi-turn primary winding is disposed within the casing in coaxial relationship therein. In a second embodiment, means are provided for forming the casing as a multi-turn secondary. The transformer is characterized by minimized resistance heating, minimized external magnetic flux, and an economical construction.

  19. Simultaneously precise frequency transfer and time synchronization using feed-forward compensation technique via 120 km fiber link.

    PubMed

    Chen, Xing; Lu, Jinlong; Cui, Yifan; Zhang, Jian; Lu, Xing; Tian, Xusheng; Ci, Cheng; Liu, Bo; Wu, Hong; Tang, Tingsong; Shi, Kebin; Zhang, Zhigang

    2015-12-22

    Precision time synchronization between two remote sites is desired in many applications such as global positioning satellite systems, long-baseline interferometry, coherent radar detection and fundamental physics constant measurements. The recently developed frequency dissemination technologies based on optical fiber link have improved the transfer instability to the level of 10(-19)/day at remote location. Therefore it is possible to keep clock oscillation at remote locations continuously corrected, or to reproduce a "virtual" clock on the remote location. However the initial alignment and the correction of 1 pps timing signal from time to time are still required, besides the highly stabilized clock frequency transfer between distant locations. Here we demonstrate a time synchronization based on an ultra-stable frequency transfer system via 120-km commercial fiber link by transferring an optical frequency comb. Both the phase noise compensation in frequency dissemination and temporal basis alignment in time synchronization were implemented by a feed-forward digital compensation (FFDC) technique. The fractional frequency instability was measured to be 6.18 × 10(-20) at 2000 s. The timing deviation of time synchronization was measured to be 0.6 ps in 1500 s. This technique also can be applied in multi-node fiber network topology.

  20. Simultaneously precise frequency transfer and time synchronization using feed-forward compensation technique via 120 km fiber link

    PubMed Central

    Chen, Xing; Lu, Jinlong; Cui, Yifan; Zhang, Jian; Lu, Xing; Tian, Xusheng; Ci, Cheng; Liu, Bo; Wu, Hong; Tang, Tingsong; Shi, Kebin; Zhang, Zhigang

    2015-01-01

    Precision time synchronization between two remote sites is desired in many applications such as global positioning satellite systems, long-baseline interferometry, coherent radar detection and fundamental physics constant measurements. The recently developed frequency dissemination technologies based on optical fiber link have improved the transfer instability to the level of 10−19/day at remote location. Therefore it is possible to keep clock oscillation at remote locations continuously corrected, or to reproduce a “virtual” clock on the remote location. However the initial alignment and the correction of 1 pps timing signal from time to time are still required, besides the highly stabilized clock frequency transfer between distant locations. Here we demonstrate a time synchronization based on an ultra-stable frequency transfer system via 120-km commercial fiber link by transferring an optical frequency comb. Both the phase noise compensation in frequency dissemination and temporal basis alignment in time synchronization were implemented by a feed-forward digital compensation (FFDC) technique. The fractional frequency instability was measured to be 6.18 × 10−20 at 2000 s. The timing deviation of time synchronization was measured to be 0.6 ps in 1500 s. This technique also can be applied in multi-node fiber network topology. PMID:26691731

  1. Simultaneously precise frequency transfer and time synchronization using feed-forward compensation technique via 120 km fiber link

    NASA Astrophysics Data System (ADS)

    Chen, Xing; Lu, Jinlong; Cui, Yifan; Zhang, Jian; Lu, Xing; Tian, Xusheng; Ci, Cheng; Liu, Bo; Wu, Hong; Tang, Tingsong; Shi, Kebin; Zhang, Zhigang

    2015-12-01

    Precision time synchronization between two remote sites is desired in many applications such as global positioning satellite systems, long-baseline interferometry, coherent radar detection and fundamental physics constant measurements. The recently developed frequency dissemination technologies based on optical fiber link have improved the transfer instability to the level of 10-19/day at remote location. Therefore it is possible to keep clock oscillation at remote locations continuously corrected, or to reproduce a “virtual” clock on the remote location. However the initial alignment and the correction of 1 pps timing signal from time to time are still required, besides the highly stabilized clock frequency transfer between distant locations. Here we demonstrate a time synchronization based on an ultra-stable frequency transfer system via 120-km commercial fiber link by transferring an optical frequency comb. Both the phase noise compensation in frequency dissemination and temporal basis alignment in time synchronization were implemented by a feed-forward digital compensation (FFDC) technique. The fractional frequency instability was measured to be 6.18 × 10-20 at 2000 s. The timing deviation of time synchronization was measured to be 0.6 ps in 1500 s. This technique also can be applied in multi-node fiber network topology.

  2. Absolute frequency measurement of the 88Sr+ clock transition using a GPS link to the SI second

    NASA Astrophysics Data System (ADS)

    Dubé, Pierre; E Bernard, John; Gertsvolf, Marina

    2017-06-01

    We report the results of a recent measurement of the absolute frequency of the 5s{{ }2}{{S}1/2} - 4d{{ }2}{{D}5/2} transition of the {{}88}\\text{Sr}{{}+} ion. The optical frequency was measured against the international atomic time realization of the SI second on the geoid as obtained by frequency transfer using a global positioning system link and the precise point positioning technique. The measurement campaign yielded more than 100 h of frequency data. It was performed with improvements to the stability and accuracy of the single-ion clock compared to the last measurement made in 2012. The single ion clock uncertainty is evaluated at 1.5× {{10}-17} when contributions from acousto-optic modulator frequency chirps and servo errors are taken into account. The stability of the ion clock is 3× {{10}-15} at 1 s averaging, a factor of three better than in the previous measurement. The results from the two measurement campaigns are in good agreement. The uncertainty of the measurement, primarily from the link to the SI second, is 0.75 Hz (1.7× {{10}-15} ). The frequency measured for the S-D clock transition of {{}88}\\text{S}{{\\text{r}}+} is {ν0}= 444 779 044 095 485.27(75) Hz.

  3. Application of Low- and Mid-Frequency Raman Spectroscopy to Characterize the Amorphous-Crystalline Transformation of Indomethacin.

    PubMed

    Larkin, Peter J; Wasylyk, John; Raglione, Michaella

    2015-11-01

    Raman spectroscopy using the mid-frequency (1800-1500 cm(-1)) and low-frequency (200-8 cm(-1)) spectral regions is used to study the transformation of amorphous indomethacin (IND) to the γ-crystalline form. The low-frequency spectral region provides access to collective vibrations of molecules in the crystalline and amorphous state, while the mid-frequency spectral region provides access to the molecular vibrations that are sensitive to the local functional group environment. Both spectral regions provide distinct Raman bands for the amorphous and crystalline forms of IND. The more intense low-frequency Raman bands provide greater sensitivity for detecting the onset of crystallization in an amorphous matrix. Subtle differences in the behavior of the initial crystalline process of IND are observed between the low-frequency and mid-frequency Raman bands. These observations suggest that different responses for mid- and low-frequency Raman bands occur for the microcrystalline domains present during the initial crystallization process. The suitability of low-frequency Raman spectroscopy to monitor IND in a suspension was demonstrated. This suggests that the technique will be a valuable tool for at-line and on-line monitoring of active pharmaceutical ingredient crystallization.

  4. Time-frequency analysis of nonstationary vibration signals for deployable structures by using the constant-Q nonstationary gabor transform

    NASA Astrophysics Data System (ADS)

    Liu, Tao; Yan, Shaoze; Zhang, Wei

    2016-06-01

    Deployable structures have been widely used in on-orbit servicing spacecrafts, and the vibration properties of such structures have become increasingly important in the aerospace industry. The constant-Q nonstationary Gabor transform (CQ-NSGT) is introduced in this paper to accurately evaluate the variation in the frequency and amplitude of vibration signals along with time. First, an example signal is constructed on the basis of the vibration properties of deployable structures and is processed by the short-time Fourier transform, Wigner-Ville distribution, Hilbert-Huang transform, and CQ-NSGT. Results show that time and frequency resolutions are simultaneously fine only by employing CQ-NSGT. Subsequently, a zero padding operation is conducted to correct the calculation error at the end of the transform results. Finally, a set of experimental devices is constructed. The vibration signal of the experimental mode is processed by CQ-NSGT. On this basis, the experimental signal properties are discussed. This time-frequency method may be useful for formulating the dynamics for complex deployable structures.

  5. Leader identity as an antecedent of the frequency and consistency of transformational, consideration, and abusive leadership behaviors.

    PubMed

    Johnson, Russell E; Venus, Merlijn; Lanaj, Klodiana; Mao, Changguo; Chang, Chu-Hsiang

    2012-11-01

    Drawing from identity-based theories of leadership, we examined relations of leader identity with leader behavior and perceived effectiveness. To do so, we employed multiwave methodology to examine the differential impact of leaders' chronic collective, relational, and individual identities on the frequency and consistency of their subsequent transformational, consideration, and abusive behaviors over a 3-week period. We also examined the relative importance of these leadership behaviors for predicting perceived leader effectiveness as rated by subordinates and peers. Results indicated that leaders' collective and individual identities were uniquely related to transformational and abusive behaviors, respectively. We also observed a significant collective by individual identity interaction, such that abusive behaviors were most frequent when a strong individual identity was paired with a weak collective identity. Frequency of transformational behaviors accounted for the largest proportion of variance in perceived leader effectiveness, followed by frequency of abusive behaviors and consistency of transformational behaviors. We discuss the implications of these findings for leadership theory and development. (c) 2012 APA, all rights reserved.

  6. A 75 GHz regenerative dynamic frequency divider with active transformer using InGaAs/InP HBT technology

    NASA Astrophysics Data System (ADS)

    Wang, Xi; Zhang, Bichan; Zhao, Hua; Su, Yongbo; Muhammad, Asif; Guo, Dong; Jin, Zhi

    2017-08-01

    This letter presents a high speed 2:1 regenerative dynamic frequency divider with an active transformer fabricated in 0.7 μm InP DHBT technology with {f}{{T}} of 165 GHz and {f}\\max of 230 GHz. The circuit includes a two-stage active transformer, input buffer, divider core and output buffer. The core part of the frequency divider is composed of a double-balanced active mixer (widely known as the Gilbert cell) and a regenerative feedback loop. The active transformer with two stages can contribute to positive gain and greatly improve phase difference. Instead of the passive transformer, the active one occupies a much smaller chip area. The area of the chip is only 469× 414 μ {{{m}}}2 and it entirely consumes a total DC power of only 94.6 mW from a single -4.8 V DC supply. The measured results present that the divider achieves an operating frequency bandwidth from 75 to 80 GHz, and performs a -23 dBm maximum output power at 37.5 GHz with a 0 dBm input signal of 75 GHz.

  7. Rolling element bearing defect detection using the generalized synchrosqueezing transform guided by time-frequency ridge enhancement.

    PubMed

    Li, Chuan; Sanchez, Vinicio; Zurita, Grover; Cerrada Lozada, Mariela; Cabrera, Diego

    2016-01-01

    Healthy rolling element bearings are vital guarantees for safe operation of the rotating machinery. Time-frequency (TF) signal analysis is an effective tool to detect bearing defects under time-varying shaft speed condition. However, it is a challenging work dealing with defective characteristic frequency and rotation frequency simultaneously without a tachometer. For this reason, a technique using the generalized synchrosqueezing transform (GST) guided by enhanced TF ridge extraction is suggested to detect the existence of the bearing defects. The low frequency band and the resonance band are first chopped from the Fourier spectrum of the bearing vibration measurements. The TF information of the lower band component and the resonance band envelope are represented using short-time Fourier transform, where the TF ridge are extracted by harmonic summation search and ridge candidate fusion operations. The inverse of the extracted TF ridge is subsequently used to guide the GST mapping the chirped TF representation to the constant one. The rectified TF pictures are then synchrosqueezed as sharper spectra where the rotation frequency and the defective characteristic frequency can be identified, respectively. Both simulated and experimental signals were used to evaluate the present technique. The results validate the effectiveness of the suggested technique for the bearing defect detection. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  8. Links between clay transformation and earthquakes along the Costa Rican subduction margin

    NASA Astrophysics Data System (ADS)

    Lauer, Rachel M.; Saffer, Demian M.; Harris, Robert N.

    2017-08-01

    We investigate the depth distribution of smectite clay transformation and its along-strike variability at the Middle America Trench offshore Costa Rica. We take advantage of recent well-constrained thermal models that refine our understanding of the margin's thermal structure and which capture significant along-strike variability. Using these thermal models, together with sediment compositions defined by drilling, we compute the distribution of smectite transformation and associated fluid production. We show that the hypocenters of large (M > 6.9) well-located megathrust earthquakes lie consistently downdip of peak fluid production. We suggest that silica cementation associated with smectite transformation promotes lithification and slip-weakening behavior that, in combination with declining fluid pressures, facilitate the initiation of unstable slip. The earthquake ruptures extend updip into the region of peak reaction, possibly due to excess pore pressures that facilitate their propagation. These results are consistent with the hypothesis that smectite transformation contributes to the onset of stick-slip behavior and acts as an important control on earthquake nucleation and propagation.

  9. Organizing the "Productive Transformation of Knowledge": Linking University and Industry in Traditional Manufacturing Areas

    ERIC Educational Resources Information Center

    Balduzzi, Giacomo; Rostan, Michele

    2016-01-01

    The article aims at underlining the role played by extra-academic and autonomous organizations strongly connected with university institutions and researchers in producing, acquiring, transferring and transforming knowledge. The study examines a particular Italian case, the "Politecnico Calzaturiero", a private institution providing…

  10. Organizing the "Productive Transformation of Knowledge": Linking University and Industry in Traditional Manufacturing Areas

    ERIC Educational Resources Information Center

    Balduzzi, Giacomo; Rostan, Michele

    2016-01-01

    The article aims at underlining the role played by extra-academic and autonomous organizations strongly connected with university institutions and researchers in producing, acquiring, transferring and transforming knowledge. The study examines a particular Italian case, the "Politecnico Calzaturiero", a private institution providing…

  11. Hemorrhagic transformation and cerebral edema in acute ischemic stroke: Link to cerebral autoregulation

    PubMed Central

    Castro, Pedro; Azevedo, Elsa; Serrador, Jorge; Rocha, Isabel; Sorond, Farzaneh

    2017-01-01

    Background Hemorrhagic transformation and cerebral edema are feared complications of acute ischemic stroke but mechanisms are poorly understood and reliable early markers are lacking. Early assessment of cerebrovascular hemodynamics may advance our knowledge in both areas. We examined the relationship between dynamic cerebral autoregulation (CA) in the early hours post ischemia, and the risk of developing hemorrhagic transformation and cerebral edema at 24 h post stroke Methods We prospectively enrolled 46 patients from our center with acute ischemic stroke in the middle cerebral artery territory. Cerebrovascular resistance index was calculated. Dynamic CA was assessed by transfer function analysis (coherence, phase and gain) of the spontaneous blood flow velocity and blood pressure oscillations. Infarct volume, hemorrhagic transformation, cerebral edema, and white matter changes were collected from computed tomography performed at presentation and 24 h. Results At admission, phase was lower (worse CA) in patients with hemorrhagic transformation [6.6 ± 30 versus 45 ± 38°; adjusted odds ratio 0.95 (95% confidence internal 0.94–0.98), p = 0.023] and with cerebral edema [6.6 ± 30 versus 45 ± 38°, adjusted odds ratio 0.96 (0.92–0.999), p = 0.044]. Progression to edema was associated with lower cerebrovascular resistance (1.4 ± 0.2 versus 2.3 ± 1.5 mm Hg/cm/s, p = 0.033) and increased cerebral blood flow velocity (51 ± 25 versus 42 ± 17 cm/s, p = 0.033) at presentation. All hemodynamic differences resolved at 3 months Conclusions Less effective CA in the early hour post ischemic stroke is associated with increased risk of hemorrhagic transformation and cerebral edema, possibly reflecting breakthrough hyperperfusion and microvascular injury. Early assessment of dynamic CA could be useful in identifying individuals at risk for these complications. PMID:28017224

  12. Hemorrhagic transformation and cerebral edema in acute ischemic stroke: Link to cerebral autoregulation.

    PubMed

    Castro, Pedro; Azevedo, Elsa; Serrador, Jorge; Rocha, Isabel; Sorond, Farzaneh

    2017-01-15

    Hemorrhagic transformation and cerebral edema are feared complications of acute ischemic stroke but mechanisms are poorly understood and reliable early markers are lacking. Early assessment of cerebrovascular hemodynamics may advance our knowledge in both areas. We examined the relationship between dynamic cerebral autoregulation (CA) in the early hours post ischemia, and the risk of developing hemorrhagic transformation and cerebral edema at 24h post stroke METHODS: We prospectively enrolled 46 patients from our center with acute ischemic stroke in the middle cerebral artery territory. Cerebrovascular resistance index was calculated. Dynamic CA was assessed by transfer function analysis (coherence, phase and gain) of the spontaneous blood flow velocity and blood pressure oscillations. Infarct volume, hemorrhagic transformation, cerebral edema, and white matter changes were collected from computed tomography performed at presentation and 24h. At admission, phase was lower (worse CA) in patients with hemorrhagic transformation [6.6±30 versus 45±38°; adjusted odds ratio 0.95 (95% confidence internal 0.94-0.98), p=0.023] and with cerebral edema [6.6±30 versus 45±38°, adjusted odds ratio 0.96 (0.92-0.999), p=0.044]. Progression to edema was associated with lower cerebrovascular resistance (1.4±0.2 versus 2.3±1.5mmHg/cm/s, p=0.033) and increased cerebral blood flow velocity (51±25 versus 42±17cm/s, p=0.033) at presentation. All hemodynamic differences resolved at 3months CONCLUSIONS: Less effective CA in the early hour post ischemic stroke is associated with increased risk of hemorrhagic transformation and cerebral edema, possibly reflecting breakthrough hyperperfusion and microvascular injury. Early assessment of dynamic CA could be useful in identifying individuals at risk for these complications. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Research on Shore-Ship Photonic Link Performance for Two- Frequency-Band Signals

    NASA Astrophysics Data System (ADS)

    Zuo, Yanqin; Cong, Bo

    2016-02-01

    Ka and Ku bands links for shore-ship communications suffer limited bandwidth and high loss. In this paper, photonics-based links are proposed and modeled. The principle of phase modulation (PM) is elaborated and analyzed. It is showed that PM can effectively suppress high-order inter-modulation distortion (IMD), reduce the insert loss and improve the reliability of the system.

  14. Ring resonator-based on-chip modulation transformer for high-performance phase-modulated microwave photonic links.

    PubMed

    Zhuang, Leimeng; Taddei, Caterina; Hoekman, Marcel; Leinse, Arne; Heideman, René; van Dijk, Paulus; Roeloffzen, Chris

    2013-11-04

    In this paper, we propose and experimentally demonstrate a novel wideband on-chip photonic modulation transformer for phase-modulated microwave photonic links. The proposed device is able to transform phase-modulated optical signals into intensity-modulated versions (or vice versa) with nearly zero conversion of laser phase noise to intensity noise. It is constructed using waveguide-based ring resonators, which features simple architecture, stable operation, and easy reconfigurability. Beyond the stand-alone functionality, the proposed device can also be integrated with other functional building blocks of photonic integrated circuits (PICs) to create on-chip complex microwave photonic signal processors. As an application example, a PIC consisting of two such modulation transformers and a notch filter has been designed and realized in TriPleX(TM) waveguide technology. The realized device uses a 2 × 2 splitting circuit and 3 ring resonators with a free spectral range of 25 GHz, which are all equipped with continuous tuning elements. The device can perform phase-to-intensity modulation transform and carrier suppression simultaneously, which enables high-performance phase-modulated microwave photonics links (PM-MPLs). Associated with the bias-free and low-complexity advantages of the phase modulators, a single-fiber-span PM-MPL with a RF bandwidth of 12 GHz (3 dB-suppression band 6 to 18 GHz) has been demonstrated comprising the proposed PIC, where the achieved spurious-free dynamic range performance is comparable to that of Class-AB MPLs using low-biased Mach-Zehnder modulators.

  15. Structural and metabolic studies of O-linked fucose-containing proteins of normal and virally-transformed rat fibroblasts

    SciTech Connect

    Morton, P.A.

    1985-01-01

    Previous studies in this laboratory have demonstrated that cultured human and rodent cells contain a series of low molecular weight glycosylated amino acids of unusual structure, designated amino acid fucosides. The incorporation of radiolabelled-fucose into one of these components, designated FL4a (glucosylfucosylthreonine), is markedly-reduced in transformed epithelial and fibroblastic cells. The authors have examined fucose-labelled normal and virally-transformed rat fibroblast cell lines for glycoproteins which might be precursors to amino acid fucosides. Using milk alkaline/borohydride treatment (the beta-elimination reaction) to release O-linked oligosaccharides from proteins, they have isolated and partially characterized two low M/sub r/ reaction products (designated DS-ol and TS-ol) released from macromolecular cell material. The identity of one of these components (DS-ol, glucosylfucitol) suggested the existence in these cells of a direct protein precursor to FL4a. They examined fucose-labelled macromolecular cell material for proteins which release DS-ol (DS-proteins.). Using gel filtration chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) with subsequent autoradiography, they have observed DS-proteins which appear to exhibit a broad molecular weight size range, and are also present in culture medium from normal and transformed cells. The findings suggest that mammalian cells contain DS-proteins and TS-proteins with a novel carbohydrate-peptide linkage wherein L-fucose is O-linked to a polypeptide backbone. Metabolic studies were undertaken to examine both the relationship between DS-protein and FL4a and the biochemical basis for the decreased level of FL4a and the biochemical basis for the decreased level of FL4a observed in transformed cells.

  16. Dual frequency feed system for the CTS communications link characterization experiment

    NASA Technical Reports Server (NTRS)

    Gill, G. J.

    1976-01-01

    The developing, testing and installation of a dual frequency feed assembly were described. The feed has been designed to receive signals in the frequency range 11.7 to 12.2 GHz and transmit signals in the frequency range 14.12 GHz plus or minus 250 MHz. Complete performance data of the feed alone and installed in the 15 foot antenna is included herein. Drawings and descriptive information of the feed assembly are also given.

  17. Building a Linked Learning Pathway: A Guide for Transforming High Schools for College and Career Success

    ERIC Educational Resources Information Center

    Atterbury, Rob

    2014-01-01

    This guide provides an overview of a more robust online guide and toolkit available through ConnectEd Studios. It supplies a glimpse of the sequence of steps involved in creating a new Linked Learning pathway. This publication can help coaches, district leadership, and pathway teams gain an understanding of the overall process of designing and…

  18. Linking a completely three-dimensional nanostrain to a structural transformation eigenstrain.

    PubMed

    Tirry, Wim; Schryvers, Dominique

    2009-09-01

    Ni-Ti is one of the most popular shape-memory alloys, a phenomenon resulting from a martensitic transformation. Commercial Ni-Ti-based alloys are often thermally treated to contain Ni(4)Ti(3) precipitates. The presence of these precipitates can introduce an extra transformation step related to the so-called R-phase. It is believed that the strain field surrounding the precipitates, caused by the matrix-precipitate lattice mismatch, lies at the origin of this intermediate transformation step. Atomic-resolution transmission electron microscopy in combination with geometrical phase analysis is used to measure the elastic strain field surrounding these precipitates. By combining measurements from two different crystallographic directions, the three-dimensional strain matrix is determined from two-dimensional measurements. Comparison of the measured strain matrix to the eigenstrain of the R-phase shows that both are very similar and that the introduction of the R-phase might indeed compensate the elastic strain introduced by the precipitate.

  19. Adaptive ground implemented phased array. [evaluation to overcome radio frequency interference characteristics of TDRS VHF return link

    NASA Technical Reports Server (NTRS)

    Smith, J. M.

    1973-01-01

    Tests were conducted to determine the feasibility of using an adaptive ground implemented phased array (AGIPA) to overcome the limitations of the radio frequency interference limited low data Tracking and Data Relay Satellite VHF return link. A feasibility demonstration model of a single user channel AFIPA system was designed, developed, fabricated, and evaluated. By scaling the frequency and aperture geometry from VHF to S-band, the system performance was more easily demonstrated in the controlled environment of an anechoic chamber. The testing procedure employs an AGIPA in which received signals from each element of the array are processed on the ground to form an adaptive, independent, computer controlled beam for each user.

  20. A new time-frequency method to reveal quantum dynamics of atomic hydrogen in intense laser pulses: Synchrosqueezing transform

    SciTech Connect

    Sheu, Yae-lin; Hsu, Liang-Yan; Wu, Hau-tieng; Li, Peng-Cheng; Chu, Shih-I

    2014-11-15

    This study introduces a new adaptive time-frequency (TF) analysis technique, the synchrosqueezing transform (SST), to explore the dynamics of a laser-driven hydrogen atom at an ab initio level, upon which we have demonstrated its versatility as a new viable venue for further exploring quantum dynamics. For a signal composed of oscillatory components which can be characterized by instantaneous frequency, the SST enables rendering the decomposed signal based on the phase information inherited in the linear TF representation with mathematical support. Compared with the classical type of TF methods, the SST clearly depicts several intrinsic quantum dynamical processes such as selection rules, AC Stark effects, and high harmonic generation.

  1. Study of the generator/motor operation of induction machines in a high frequency link space power system

    NASA Technical Reports Server (NTRS)

    Lipo, Thomas A.; Sood, Pradeep K.

    1987-01-01

    Static power conversion systems have traditionally utilized dc current or voltage source links for converting power from one ac or dc form to another since it readily achieves the temporary energy storage required to decouple the input from the output. Such links, however, result in bulky dc capacitors and/or inductors and lead to relatively high losses in the converters due to stresses on the semiconductor switches. The feasibility of utilizing a high frequency sinusoidal voltage link to accomplish the energy storage and decoupling function is examined. In particular, a type of resonant six pulse bridge interface converter is proposed which utilizes zero voltage switching principles to minimize switching losses and uses an easy to implement technique for pulse density modulation to control the amplitude, frequency, and the waveshape of the synthesized low frequency voltage or current. Adaptation of the proposed topology for power conversion to single-phase ac and dc voltage or current outputs is shown to be straight forward. The feasibility of the proposed power circuit and control technique for both active and passive loads are verified by means of simulation and experiment.

  2. Formation and Evolution of the San Cristobal Trough Transform Fault Linking the Southern Solomon Islands and Northern New Hebrides Trenches

    NASA Astrophysics Data System (ADS)

    Furlong, K. P.; Hayes, G. P.; Herman, M. W.; Benz, H.

    2014-12-01

    The San Cristobal Trough, which occupies the southern segment of the South Solomon Trench, hosts a dominantly left-lateral transform plate boundary (SCTF) linking the southern end of the Solomon Islands subduction zone (SISZ) to the northern end of the New Hebrides (Vanuatu) subduction zone (NHSZ). At its western end (SISZ), the Australia plate is torn as a result of the transition from subduction to transform motion. The southern side of the tear translates approximately 375 km along the SCTF before subducting beneath the Santa Cruz Islands at the NHSZ. Earthquakes occurring along this transform reflect the processes of plate tearing, fault zone evolution, and subsequent underthrusting and subduction of the Australia-plate-side of the transform. A knot of earthquake activity at the western end of the SCTF juxtaposes high-angle thrust faulting events with left-lateral strike slip events. These record the tearing of Australian lithosphere, as shown by a recent pair of large earthquakes in that region - a Mw 7.6 strike-slip event (12 April 2014) followed 22 hours later by a Mw 7.4 high-angle reverse faulting event (13 April 2014). Associated displacements reflect oblique tearing (northern-side down and west), allowing the Australia Plate to follow two disparate paths - subduction at the SISZ to the north and translation along the SCTF to the south. Moving eastward along the transform, the plate boundary shows three styles of earthquake activity. The main transform is dominated by shallow, E-W striking, left-lateral faulting and E-W striking thrust faults (with a north-dipping shallow fault plane) - these reflect partitioning of oblique motion along the transform between the Australia and Pacific plates. Outboard (+/- 100 km) of the plate boundary, a group of E-W striking shallow normal faulting events reflect upward bending driven by the convergent component of plate motions. Approaching the NHSZ, normal faulting earthquakes in the Australia Plate rotate clockwise

  3. Perspective: Transformative learning: a framework using critical reflection to link the improvement competencies in graduate medical education.

    PubMed

    Wittich, Christopher M; Reed, Darcy A; McDonald, Furman S; Varkey, Prathibha; Beckman, Thomas J

    2010-11-01

    Quality improvement (QI) in health care involves activities ranging from enhancing personal practice to reforming the larger health care system. The Accreditation Council for Graduate Medical Education recognizes this broad definition of QI in its requirement that physicians-in-training demonstrate competence in practice-based learning and improvement (PBLI) and systems-based practice (SBP). Creative metaphors have been used to teach the PBLI and SBP competencies, but conceptual frameworks describing the relationship between these competencies are needed. Transformative learning is an adult education theory that states individuals must critically reflect on life events in order to change their beliefs or behaviors. The authors propose that critical reflection during transformative learning can conceptually link PBLI and SBP. Reflection on personal experience with suboptimal patient care leads to recognizing personal or system limitations. Addressing personal limitations improves individual practice (PBLI), whereas applying QI methodologies leads to large-scale improvements (SBP). Educators who adopt the transformative learning framework should be able to design meaningful QI curricula that encourage residents to be reflective and empower them with QI skills.

  4. A Fast Hartley Transform based novel optical OFDM system for VLC indoor application with constant envelope PAPR reduction technique using frequency modulation

    NASA Astrophysics Data System (ADS)

    Singh, Vinay Kumar; Dalal, U. D.

    2017-10-01

    In this research literature we present a unique optical OFDM system for Visible Light Communication (VLC) intended for indoor application which uses a non conventional transform-Fast Hartley Transform and an effective method to reduce the peak to average power ratio (PAPR) of the OFDM signal based on frequency modulation leading to a constant envelope (CE) signal. The proposed system is analyzed by a complete mathematical model and verified by the concurrent simulations results. The use of the non conventional transform makes the system computationally more desirable as it does not require the Hermitian symmetry constraint to yield real signals. The frequency modulation of the baseband signal converge random peaks into a CE signal. This leads to alleviation of the non linearity effects of the LED used in the link for electrical to optical conversion. The PAPR is reduced to 2 dB by this technique in this work. The impact of the modulation index on the performance of the system is also investigated. An optimum modulation depth of 30% gives better results. The additional phase discontinuity incurring on the demodulated signal at the receiver is also significantly reduced. A comparison of the improvement in phase discontinuity of the proposed technique of combating the PAPR with the previously known phase modulation technique is also presented in this work. Based on the channel metrics we evaluate the system performance and report an improvement of 1.2 dB at the FEC threshold. The proposed system is simple in design and computationally efficient and this can be incorporated into the present VLC system without much alteration thereby making it a cost effective solution.

  5. First results of the 74-MHz Very Large Array-Pie Town link. Hercules A at low frequencies

    NASA Astrophysics Data System (ADS)

    Gizani, Nectaria A. B.; Cohen, A.; Kassim, N. E.

    2005-04-01

    We present the results of the first successful observations of the Pie Town link with the Very Large Array at 74 MHz on Hercules A. The improvement in resolution from 25 to 10 arcsec resolves the helical- and ring-like features seen at higher frequencies. We also present new high dynamic range images of this powerful radio galaxy at 325 MHz. Our low-frequency observations confirm the multiple outburst interpretation of the spectral index differences at high frequencies. A comparison between our radio and ROSAT X-ray data does not reveal any association between the X-ray emission from the cluster and the radio lobes. There are no extra regions of radio emission at 74 MHz.

  6. A three-phase three-winding core-type transformer model for low-frequency transient studies

    SciTech Connect

    Chen, X.; Venkata, S.S.

    1997-04-01

    A topology-based and duality-derived three-phase, three-winding, core-type transformer model is presented. The model treats the leakage inductances and the coupling effects of the core in a straightforward and integrated way. The long-established positive- and zero-sequence star equivalent circuits of a three-phase three-winding transformer are derived from the original equivalent magnetic circuit of the transformer by applying duality. Formulations for determining the values of the leakage inductances and the core loss resistances from transformer open- and short-circuit test data are presented. A supporting routine is written to generate the {lambda}-i curves for each segment of the core and the other input data for EMTP. Since the duality-derived model consists of only RLC elements, no device-specific code to EMTP time-step code is needed. Winding capacitances are lumped to the terminals. The model is suitable for simulation of power system low-frequency transients such as inrush currents and ferroresonance, short circuits, and abnormalities including transformer winding faults.

  7. Time-frequency spectral analysis of TMS-evoked EEG oscillations by means of Hilbert-Huang transform.

    PubMed

    Pigorini, Andrea; Casali, Adenauer G; Casarotto, Silvia; Ferrarelli, Fabio; Baselli, Giuseppe; Mariotti, Maurizio; Massimini, Marcello; Rosanova, Mario

    2011-06-15

    A single pulse of Transcranial Magnetic Stimulation (TMS) generates electroencephalogram (EEG) oscillations that are thought to reflect intrinsic properties of the stimulated cortical area and its fast interactions with other cortical areas. Thus, a tool to decompose TMS-evoked oscillations in the time-frequency domain on a millisecond timescale and on a broadband frequency range may help to understand information transfer across cortical oscillators. Some recent studies have employed algorithms based on the Wavelet Transform (WT) to study TMS-evoked EEG oscillations in healthy and pathological conditions. However, these methods do not allow to describe TMS-evoked EEG oscillations with high resolution in time and frequency domains simultaneously. Here, we first develop an algorithm based on Hilbert-Huang Transform (HHT) to compute statistically significant time-frequency spectra of TMS-evoked EEG oscillations on a single trial basis. Then, we compared the performances of the HHT-based algorithm with the WT-based one by applying both of them to a set of simulated signals. Finally, we applied both algorithms to real TMS-evoked potentials recorded in healthy or schizophrenic subjects. We found that the HHT-based algorithm outperforms the WT-based one in detecting the time onset of TMS-evoked oscillations in the classical EEG bands. These results suggest that the HHT-based algorithm may be used to study the communication between different cortical oscillators on a fine time scale.

  8. Postischemic hyperperfusion on arterial spin labeled perfusion MRI is linked to hemorrhagic transformation in stroke

    PubMed Central

    Yu, Songlin; Liebeskind, David S; Dua, Sumit; Wilhalme, Holly; Elashoff, David; Qiao, Xin J; Alger, Jeffry R; Sanossian, Nerses; Starkman, Sidney; Ali, Latisha K; Scalzo, Fabien; Lou, Xin; Yoo, Bryan; Saver, Jeffrey L; Salamon, Noriko; Wang, Danny JJ

    2015-01-01

    The purpose of this study was to investigate the relationship between hyperperfusion and hemorrhagic transformation (HT) in acute ischemic stroke (AIS). Pseudo-continuous arterial spin labeling (ASL) with background suppressed 3D GRASE was performed during routine clinical magnetic resonance imaging (MRI) on AIS patients at various time points. Arterial spin labeling cerebral blood flow (CBF) maps were visually inspected for the presence of hyperperfusion. Hemorrhagic transformation was followed during hospitalization and was graded on gradient recalled echo (GRE) scans into hemorrhagic infarction (HI) and parenchymal hematoma (PH). A total of 361 ASL scans were collected from 221 consecutive patients with middle cerebral artery stroke from May 2010 to September 2013. Hyperperfusion was more frequently detected posttreatment (odds ratio (OR)=4.8, 95% confidence interval (CI) 2.5 to 8.9, P<0.001) and with high National Institutes of Health Stroke Scale (NIHSS) scores at admission (P<0.001). There was a significant association between having hyperperfusion at any time point and HT (OR=3.5, 95% CI 2.0 to 6.3, P<0.001). There was a positive relationship between the grade of HT and time–hyperperfusion with the Spearman's rank correlation of 0.44 (P=0.003). Arterial spin labeling hyperperfusion may provide an imaging marker of HT, which may guide the management of AIS patients post tissue-type plasminogen activator (tPA) and/or endovascular treatments. Late hyperperfusion should be given more attention to prevent high-grade HT. PMID:25564233

  9. Ground Radar Polarimetric Observations of High-Frequency Earth-Space Communication Links

    NASA Technical Reports Server (NTRS)

    Bolen, Steve; Chandrasekar, V.; Benjamin, Andrew

    2002-01-01

    Strategic roadmaps for NASA's Human Exploration and Development of Space (REDS) enterprise support near-term high-frequency communication systems that provide moderate to high data rates with dependable service. Near-earth and human planetary exploration will baseline Ka-Band, but may ultimately require the use of even higher frequencies. Increased commercial demand on low-frequency earth-space bands has also led to increased interest in the use of higher frequencies in regions like K u - and K,- band. Data is taken from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR), which operates at 13.8 GHz, and the true radar reflectivity profile is determined along the PR beam via low-frequency ground based polarimetric observations. The specific differential phase (Kdp) is measured along the beam and a theoretical model is used to determine the expected specific attenuation (k). This technique, called the k-Kdp method, uses a Fuzzy-Logic model to determine the hydrometeor type along the PR beam from which the appropriate k-Kdp relationship is used to determine k and, ultimately, the total path-integrated attenuation (PIA) on PR measurements. Measurements from PR and the NCAR S-POL radar were made during the TEFLUN-B experiment that took place near Melbourne, FL in 1998, and the TRMM-LBA campaign near Ji-Parana, Brazil in 1999.

  10. Direct high-frequency modulation of VCSELs and applications in fibre optic RF and microwave links

    NASA Astrophysics Data System (ADS)

    Larsson, Anders; Carlsson, Christina; Gustavsson, Johan; Haglund, Åsa; Modh, Peter; Bengtsson, Jörgen

    2004-11-01

    With the rapid development of wireless communication networks there is an increasing demand for efficient and cost-effective transmission and distribution of RF signals. Fibre optic RF links, employing directly modulated semiconductor lasers, provide many of the desired characteristics for such distribution systems and in the search for cost-effective solutions, the vertical cavity surface emitting laser (VCSEL) is of interest. It has therefore been the purpose of this work to investigate whether 850 nm VCSELs fulfil basic performance requirements for fibre optic RF links operating in the low-GHz range. The performance of single- and multimode oxide confined VCSELs has been compared, in order to pin-point limitations and to find the optimum design. Fibre optic RF links using VCSELs and multimode fibres have been assembled and evaluated with respect to performance characteristics of importance for wireless communication systems. We have found that optimized single-mode VCSELs provide the highest performance and that links using such VCSELs and high-bandwidth multimode fibres satisfy the requirements in a number of applications, including cellular systems for mobile communication and wireless local area networks.

  11. Input preshaping with frequency domain information for flexible-link manipulator control

    NASA Technical Reports Server (NTRS)

    Tzes, Anthony; Englehart, Matthew J.; Yurkovich, Stephen

    1989-01-01

    The application of an input preshaping scheme to flexible manipulators is considered. The resulting control corresponds to a feedforward term that convolves in real-time the desired reference input with a sequence of impulses and produces a vibration free output. The robustness of the algorithm with respect to injected disturbances and modal frequency variations is not satisfactory and can be improved by convolving the input with a longer sequence of impulses. The incorporation of the preshaping scheme to a closed-loop plant, using acceleration feedback, offers satisfactory disturbance rejection due to feedback and cancellation of the flexible mode effects due to the preshaping. A frequency domain identification scheme is used to estimate the modal frequencies on-line and subsequently update the spacing between the impulses. The combined adaptive input preshaping scheme provides the fastest possible slew that results in a vibration free output.

  12. Observation of radiation-specific damage in human cells exposed to depleted uranium: dicentric frequency and neoplastic transformation as endpoints.

    PubMed

    Miller, A C; Xu, J; Stewart, M; Brooks, K; Hodge, S; Shi, L; Page, N; McClain, D

    2002-01-01

    Depleted uranium (DU) is a dense heavy metal used primarily in military applications. Published data from our laboratory have demonstrated that DU exposure in vitro to immortalised human osteoblast cells (HOS) is both neoplastically transforming and genotoxic. DU possesses both a radiological (alpha-particle) and chemical (metal) component. Since DU has a low specific activity in comparison to natural uranium, it is not considered to be a significant radiological hazard. The potential contribution of radiation to DU-induced biological effects is unknown and the involvement of radiation in DU-induced biological effects could have significant implications for current risk estimates for internalised DU exposure. Two approaches were used to address this question. The frequency of dicentrics was measured in HOS cells following DU exposure in vitro. Data demonstrated that DU exposure (50 microM, 24 h) induced a significant elevation in dicentric frequency in vitro in contrast to incubation with the heavy metals, nickel and tungsten which did not increase dicentric frequency above background levels. Using the same concentration (50 microM) of three uranyl nitrate compounds that have different uranium isotopic concentrations and therefore, different specific activities, the effect on neoplastic transformation in vitro was examined. HOS cells were exposed to one of three-uranyl nitrate compounds (238U-uranyl nitrate, specific activity 0.33 microCi.g-1; DU-uranyl nitrate, specific activity 0.44 microCi.g-1; and 235U-uranyl nitrate, specific activity 2.2 microCi.g-1) delivered at a concentration of 50 microM for 24 h. Results showed, at equal uranium concentration, there was a specific activity dependent increase in neoplastic transformation frequency. Taken together these data suggest that radiation can play a role in DU-induced biological effects in vitro.

  13. Transformation of potential energy surfaces for estimating isotopic shifts in anharmonic vibrational frequency calculations

    SciTech Connect

    Meier, Patrick; Oschetzki, Dominik; Rauhut, Guntram; Berger, Robert

    2014-05-14

    A transformation of potential energy surfaces (PES) being represented by multi-mode expansions is introduced, which allows for the calculation of anharmonic vibrational spectra of any isotopologue from a single PES. This simplifies the analysis of infrared spectra due to significant CPU-time savings. An investigation of remaining deviations due to truncations and the so-called multi-level approximation is provided. The importance of vibrational-rotational couplings for small molecules is discussed in detail. In addition, an analysis is proposed, which provides information about the quality of the transformation prior to its execution. Benchmark calculations are provided for a set of small molecules.

  14. Gesture Frequency Linked Primarily to Story Length in 4-10-Year Old Children's Stories

    ERIC Educational Resources Information Center

    Nicoladis, Elena; Marentette, Paula; Navarro, Samuel

    2016-01-01

    Previous studies have shown that older children gesture more while telling a story than younger children. This increase in gesture use has been attributed to increased story complexity. In adults, both narrative complexity and imagery predict gesture frequency. In this study, we tested the strength of three predictors of children's gesture use in…

  15. Long-Distance Frequency Transfer Over an Urban Fiber Link Using Optical Phase Stabilization

    DTIC Science & Technology

    2008-12-01

    eliability, and the potential for phase noise cancellation. Microwave frequency transmission using amplitude odulation of an optical carrier has demonstrated...isolation box. About W of optical power, including 30% in the phase odulation sidebands, are typically sent onto the cavity ith a coupling

  16. Conflict Frequency within Mother-Child Dyads across Contexts: Links with Attachment Security and Gender

    ERIC Educational Resources Information Center

    Panfile, Tia M.; Laible, Deborah J.; Eye, Jessica L.

    2012-01-01

    The current study examined context, attachment, temperament, and gender as predictors of conflict frequency between mothers and their young children. Conflict between 40 mothers and their 36-month-old children was observed during multiple laboratory tasks with varying levels of structure, and the number of dyadic conflict episodes was totaled for…

  17. Links Between Flood Frequency and Annual Water Balance Behaviors: A Basis for Similarity and Regionalization

    SciTech Connect

    Guo, Jiali; Li, Hongyi; Leung, Lai-Yung R.; Guo, Shenglian; Liu, Pan; Sivapalan, Murugesu

    2014-03-28

    This paper presents the results of a data based comparative study of several hundred catchments across continental United States belonging to the MOPEX dataset, which systematically explored the connection between the flood frequency curve and measures of mean annual water balance. Two different measures of mean annual water balance are used: (i) a climatic aridity index, AI, which is a measure of the competition between water and energy availability at the annual scale; and, (ii) baseflow index, BFI, the ratio of slow runoff to total runoff also at the annual time scale, reflecting the role of geology, soils, topography and vegetation. The data analyses showed that the aridity index, AI, has a first order control on both the mean and Cv of annual maximum floods. While mean annual flood decreases with increasing aridity, Cv increases with increasing aridity. BFI appeared to be a second order control on the magnitude and shape of the flood frequency curve. Higher BFI, meaning more subsurface flow and less surface flow leads to a decrease of mean annual flood whereas lower BFI leads to accumulation of soil moisture and increased flood magnitudes that arise from many events acting together. The results presented in this paper provide innovative means to delineate homogeneous regions within which the flood frequency curves can be assumed to be functionally similar. At another level, understanding the connection between annual water balance and flood frequency will be another building block towards developing comprehensive understanding of catchment runoff behavior in a holistic way.

  18. Characterization of In-Body to On-Body Wireless Radio Frequency Link for Upper Limb Prostheses.

    PubMed

    Stango, Antonietta; Yazdandoost, Kamya Yekeh; Negro, Francesco; Farina, Dario

    2016-01-01

    Wireless implanted devices can be used to interface patients with disabilities with the aim of restoring impaired motor functions. Implanted devices that record and transmit electromyographic (EMG) signals have been applied for the control of active prostheses. This simulation study investigates the propagation losses and the absorption rate of a wireless radio frequency link for in-to-on body communication in the medical implant communication service (MICS) frequency band to control myoelectric upper limb prostheses. The implanted antenna is selected and a suitable external antenna is designed. The characterization of both antennas is done by numerical simulations. A heterogeneous 3D body model and a 3D electromagnetic solver have been used to model the path loss and to characterize the specific absorption rate (SAR). The path loss parameters were extracted and the SAR was characterized, verifying the compliance with the guideline limits. The path loss model has been also used for a preliminary link budget analysis to determine the feasibility of such system compliant with the IEEE 802.15.6 standard. The resulting link margin of 11 dB confirms the feasibility of the system proposed.

  19. Impact of turbulence on high-precision ground-satellite frequency transfer with two-way coherent optical links

    NASA Astrophysics Data System (ADS)

    Robert, Clélia; Conan, Jean-Marc; Wolf, Peter

    2016-03-01

    Bidirectional ground-satellite laser links suffer from turbulence-induced scintillation and phase distortion. We study the impact of turbulence on coherent detection and the related phase noise that restricts time and frequency transfer precision. We evaluate the capacity to obtain a two-way cancellation of atmospheric effects despite the asymmetry between up- and downlink that limits the link reciprocity. For ground-satellite links, the asymmetry is induced by point-ahead angle and possibly the use, for the ground terminal, of different transceiver diameters, in reception and emission. The quantitative analysis is obtained thanks to refined end-to-end simulations under realistic turbulence and wind conditions as well as satellite kinematics. These temporally resolved simulations allow characterizing the coherent detection in terms of time series of heterodyne efficiency and phase noise for different system parameters. We show that tip-tilt correction on ground is mandatory at reception for the downlink and as a pre-compensation of the uplink. Besides, thanks to the large tilt angular correlation, the correction is shown to be efficient on uplink despite the point-ahead angle. Very good two-way compensation of turbulent effects is obtained even with the asymmetries. The two-way differential phase noise is reduced to 1 rad2 , with the best fractional frequency stability below 2 ×10-17 after 1-s averaging time.

  20. Characterization of In-Body to On-Body Wireless Radio Frequency Link for Upper Limb Prostheses

    PubMed Central

    Stango, Antonietta; Yazdandoost, Kamya Yekeh; Negro, Francesco; Farina, Dario

    2016-01-01

    Wireless implanted devices can be used to interface patients with disabilities with the aim of restoring impaired motor functions. Implanted devices that record and transmit electromyographic (EMG) signals have been applied for the control of active prostheses. This simulation study investigates the propagation losses and the absorption rate of a wireless radio frequency link for in-to-on body communication in the medical implant communication service (MICS) frequency band to control myoelectric upper limb prostheses. The implanted antenna is selected and a suitable external antenna is designed. The characterization of both antennas is done by numerical simulations. A heterogeneous 3D body model and a 3D electromagnetic solver have been used to model the path loss and to characterize the specific absorption rate (SAR). The path loss parameters were extracted and the SAR was characterized, verifying the compliance with the guideline limits. The path loss model has been also used for a preliminary link budget analysis to determine the feasibility of such system compliant with the IEEE 802.15.6 standard. The resulting link margin of 11 dB confirms the feasibility of the system proposed. PMID:27764182

  1. TRIM24 Links Glucose Metabolism with Transformation of Human Mammary Epithelial Cells

    PubMed Central

    Pathiraja, Thushangi N.; Thakkar, Kaushik N.; Jiang, Shiming; Stratton, Sabrina; Liu, Zhaoliang; Gagea, Mihai; Xi, Shi; Shah, Parantu K.; Phan, Liem; Lee, Mong-Hong; Andersen, Jannik; Stampfer, Martha; Barton, Michelle C.

    2015-01-01

    Tripartite motif 24 protein (TRIM24) is a plant homeodomain (PHD)/bromodomain histone reader, recently associated with poor overall survival of breast cancer patients. At a molecular level, TRIM24 is a negative regulator of p53 levels and a co-activator of estrogen receptor. However, the role of TRIM24 in breast tumorigenesis remains largely unknown. We used an isogenic human mammary epithelial cell (HMEC) culture model, derived from reduction mammoplasty tissue, and found that ectopic expression of TRIM24 in immortalized HMECs (TRIM24-iHMECs) greatly increased cellular proliferation and induced malignant transformation. Subcutaneous injection of TRIM24-iHMECs in nude mice led to growth of intermediate to high-grade tumors in 60-70% of mice. Molecular analysis of TRIM24-iHMECs revealed a glycolytic and tricarboxylic acid cycle gene signature, alongside increased glucose uptake and activated aerobic glycolysis. Collectively, these results identify a role for TRIM24 in breast tumorigenesis through reprogramming of glucose metabolism in HMECs, further supporting TRIM24 as a viable therapeutic target in breast cancers. PMID:25065590

  2. Time and frequency transfer with a microwave link in the ACES/PHARAO mission

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

    The Atomic Clocks Ensemble in Space (ACES/PHARAO mission), which will be installed on board the International Space Station (ISS), uses a dedicated two-way microwave link in order to compare the timescale generated on board with those provided by many ground stations disseminated on the Earth. Phase accuracy and stability of this long range link will have a key role in the success of the ACES/PHARAO experiment. SYRTE laboratory is heavily involved in the design and development of the data processing software: from theoretical modeling and numerical simulations to the development of a software prototype. Our team is working on a wide range of problems that need to be solved in order to achieve high accuracy in (almost) real time. In this article we present some key aspects of the measurement, as well as current status of the software's development.

  3. The link between texting and motor vehicle collision frequency in the orthopaedic trauma population.

    PubMed

    Issar, Neil M; Kadakia, Rishin J; Tsahakis, James M; Yoneda, Zachary T; Sethi, Manish K; Mir, Hassan R; Archer, Kristin; Obremskey, William T; Jahangir, Amir A

    2013-07-01

    This study will evaluate whether or not texting frequency while driving and/or texting frequency in general are associated with an increased risk of incurring a motor vehicle collision (MVC) resulting in orthopaedic trauma injuries. All patients who presented to the Vanderbilt University Medical Center Orthopaedic Trauma Clinic were administered a questionnaire to determine background information, mean phone use, texting frequency, texting frequency while driving, and whether or not the injury was the result of an MVC in which the patient was driving. 237 questionnaires were collected. 60 were excluded due to incomplete date, leaving 57 questionnaires in the MVC group and 120 from patients with non-MVC injuries. Patients who sent more than 30 texts per week ("heavy texters") were 2.22 times more likely to be involved in an MVC than those who texted less frequently. 84% of respondents claimed to never text while driving. Dividing the sample into subsets on the basis of age (25 years of age or below considered "young adult," and above 25 years of age considered "adult"),young, heavy texters were 6.76 times more likely to be involved in an MVC than adult non-heavy texters (p = 0.000). Similarly, young adult, non-heavy texters were 6.65 (p = 0.005) times more likely to be involved in an MVC, and adult, heavy texters were 1.72 (p = 0.186) times more likely to be involved in an MVC. Patients injured in an MVC sent more text messages per week than non-MVC patients. Additionally, controlling for age demonstrated that young age and heavy general texting frequency combined had the highest increase in MVC risk, with the former being the variable of greatest effect.

  4. The link between texting and motor vehicle collision frequency in the orthopaedic trauma population

    PubMed Central

    Issar, Neil M.; Kadakia, Rishin J.; Tsahakis, James M.; Yoneda, Zachary T.; Sethi, Manish K.; Mir, Hassan R.; Archer, Kristin; Obremskey, William T.; Jahangir, Amir A.

    2013-01-01

    Abstract: Background: This study will evaluate whether or not texting frequency while driving and/or texting frequency in general are associated with an increased risk of incurring a motor vehicle collision (MVC) resulting in orthopaedic trauma injuries. Methods: All patients who presented to the Vanderbilt University Medical Center Orthopaedic Trauma Clinic were administered a questionnaire to determine background information, mean phone use, texting frequency, texting frequency while driving, and whether or not the injury was the result of an MVC in which the patient was driving. Results: 237 questionnaires were collected. 60 were excluded due to incomplete date, leaving 57 questionnaires in the MVC group and 120 from patients with non-MVC injuries. Patients who sent more than 30 texts per week (“heavy texters”) were 2.22 times more likely to be involved in an MVC than those who texted less frequently. 84% of respondents claimed to never text while driving. Dividing the sample into subsets on the basis of age (25 years of age or below considered “young adult,” and above 25 years of age considered “adult”),young, heavy texters were 6.76 times more likely to be involved in an MVC than adult non-heavy texters (p = 0.000). Similarly, young adult, non-heavy texters were 6.65 (p = 0.005) times more likely to be involved in an MVC, and adult, heavy texters were 1.72 (p = 0.186) times more likely to be involved in an MVC. Conclusions: Patients injured in an MVC sent more text messages per week than non-MVC patients. Additionally, controlling for age demonstrated that young age and heavy general texting frequency combined had the highest increase in MVC risk, with the former being the variable of greatest effect. PMID:23416747

  5. White LED-based optical wireless link with improved transmission capacity using nonorthogonal multiamplitude phase frequency modulation

    NASA Astrophysics Data System (ADS)

    Won, Yong-Yuk; Yoon, Sang Min; Seo, Dongsun

    2017-06-01

    A nonorthogonal amplitude, phase, and frequency modulation (APFM) technique that can increase the transmission capacity of an optical wireless link based on white light-emitting diode (LED) is proposed. It is implemented by the simultaneous use of nonorthogonal frequency shift keying (FSK) and quadrature amplitude modulation (QAM). A white LED-based wireless link using a 64-APFM scheme is constructed to experimentally verify the proposed technique, where the 64-APFM scheme is implemented by the combination of nonorthogonal 4-FSK and 16-QAM. Two more bits per symbol are transmitted using the proposed scheme with the same bandwidth of QAM. No intercarrier interference effect is observed at the 0.02-% frequency spacing (0.001 MHz) for the used RF carrier (5 MHz) because the correlation between the received 64-APFM signal and only one carrier at a time is accomplished with the help of digital signal processing. 6-Mbit/s (1-Msymbol/s) data are successfully transmitted through an optical wireless channel with a limited bandwidth of 1 MHz. This indicates that six bits per symbol can be transmitted using the proposed APFM technique at the same physical bandwidth as 16-QAM.

  6. DC-DC Type High-Frequency Link DC for Improved Power Quality of Cascaded Multilevel Inverter

    NASA Astrophysics Data System (ADS)

    Sadikin, Muhammad; Senjyu, Tomonobu; Yona, Atsushi

    2013-06-01

    Multilevel inverters are emerging as a new breed of power converter options for power system applications. Recent advances in power switching devices enabled the suitability of multilevel inverters for high voltage and high power applications because they are connecting several devices in series without the need of component matching. Usually, a transformerless battery energy storage system, based on a cascaded multilevel inverter, is used as a measure for voltage and frequency deviations. System can be reduced in size, weight, and cost of energy storage system. High-frequency link circuit topology is advantageous in realizing compact and light-weight power converters for uninterruptible power supply systems, new energy systems using photovoltaic-cells, fuel-cells and so on. This paper presents a DC-DC type high-frequency link DC (HFLDC) cascaded multilevel inverter. Each converter cell is implemented a control strategy for two H-bridge inverters that are controlled with the same multicarrier pulse width modulation (PWM) technique. The proposed cascaded multilevel inverter generates lower voltage total harmonic distortion (THD) in comparison with conventional cascaded multilevel inverter. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of the proposed cascaded multilevel inverter.

  7. Dual Transformer Model based on Standard Circuit Elements for the Study of Low- and Mid-frequency Transients

    NASA Astrophysics Data System (ADS)

    Jazebi, Saeed

    This thesis is a step forward toward achieving the final objective of creating a fully dual model for transformers including eddy currents and nonlinearities of the iron core using the fundamental electrical components already available in the EMTP-type programs. The model is effective for the study of the performance of transformers during power system transients. This is very important for transformer designers, because the insulation of transformers is determined with the overvoltages caused by lightning or switching operations. There are also internally induced transients that occur when a switch is actuated. For example switching actions for reconfiguration of distribution systems that offers economic advantages, or protective actions to clear faults and large short-circuit currents. Many of the smart grid concepts currently under development by many utilities rely heavily on switching to optimize resources that produce transients in the system. On the other hand, inrush currents produce mechanical forces which deform transformer windings and cause malfunction of the differential protection. Also, transformer performance under ferroresonance and geomagnetic induced currents are necessary to study. In this thesis, a physically consistent dual model applicable to single-phase two-winding transformers is proposed. First, the topology of a dual electrical equivalent circuit is obtained from the direct application of the principle of duality. Then, the model parameters are computed considering the variations of the transformer electromagnetic behavior under various operating conditions. Current modeling techniques use different topological models to represent diverse transient situations. The reversible model proposed in this thesis unifies the terminal and topological equivalent circuits. The model remains invariable for all low-frequency transients including deep saturation conditions driven from any of the two windings. The very high saturation region of the

  8. Phase information of time-frequency transforms as a key feature for classification of atrial fibrillation episodes.

    PubMed

    Ortigosa, Nuria; Fernández, Carmen; Galbis, Antonio; Cano, Óscar

    2015-03-01

    Patients suffering from atrial fibrillation can be classified into different subtypes, according to the temporal pattern of the arrhythmia and its recurrence. Nowadays, clinicians cannot differentiate a priori between the different subtypes, and patient classification is done afterwards, when its clinical course is available. In this paper we present a comparison of classification performances when differentiating paroxysmal and persistent atrial fibrillation episodes by means of support vector machines. We analyze short surface electrocardiogram recordings by extracting modulus and phase features from several time-frequency transforms: short-time Fourier transform, Wigner-Ville, Choi-Williams, Stockwell transform, and general Fourier-family transform. Overall, accuracy higher than 81% is obtained when classifying phase information features of real test ECGs from a heterogeneous cohort of patients (in terms of progression of the arrhythmia and antiarrhythmic treatment) recorded in a tertiary center. Therefore, phase features can facilitate the clinicians' choice of the most appropriate treatment for each patient by means of a non-invasive technique (the surface ECG).

  9. Analysis and design of modified window shapes for S-transform to improve time-frequency localization

    NASA Astrophysics Data System (ADS)

    Ma, Jianping; Jiang, Jin

    2015-06-01

    This paper deals with window design issues for modified S-transform (MST) to improve the performance of time-frequency analysis (TFA). After analyzing the drawbacks of existing window functions, a window design technique is proposed. The technique uses a sigmoid function to control the window width in frequency domain. By proper selection of certain tuning parameters of a sigmoid function, windows with different width profiles can be obtained for multi-component signals. It is also interesting to note that the MST algorithm can be considered as a special case of a generalized method that adds a tunable shaping function to the standard window in frequency domain to meet specific frequency localization needs. The proposed design technique has been validated on a physical vibration test system using signals with different characteristics. The results have demonstrated that the proposed MST algorithm has superior time-frequency localization capabilities over standard ST, as well as other classical TFA methods. Subsequently, the proposed MST algorithm is applied to vibration monitoring of pipes in a water supply process controlled by a diaphragm pump for fault detection purposes.

  10. Method for all-sky searches of continuous gravitational wave signals using the frequency-Hough transform

    NASA Astrophysics Data System (ADS)

    Astone, Pia; Colla, Alberto; D'Antonio, Sabrina; Frasca, Sergio; Palomba, Cristiano

    2014-08-01

    In this paper we present a hierarchical data analysis pipeline for all-sky searches of continuous gravitational wave signals, like those emitted by spinning neutron stars asymmetric with respect to the rotation axis, with unknown position, rotational frequency, and spin-down. The core of the pipeline is an incoherent step based on a particularly efficient implementation of the Hough transform, which we call frequency-Hough, that maps the data time-frequency plane to the source frequency and spin-down plane for each fixed direction in the sky. Theoretical ROCs and sensitivity curves are computed and the dependency on various thresholds is discussed. A comparison of the sensitivity loss with respect to an "optimal" method is also presented. Several other novelties, with respect to other wide-parameter analysis pipelines, are also outlined. They concern, in particular, the construction of the grid in the parameter space, with over-resolution in frequency and parameter refinement, candidate selection, and various data cleaning steps that are introduced to improve search sensitivity and rejection of false candidates.

  11. Characterization of gear faults in variable rotating speed using Hilbert-Huang Transform and instantaneous dimensionless frequency normalization

    NASA Astrophysics Data System (ADS)

    Wu, T. Y.; Chen, J. C.; Wang, C. C.

    2012-07-01

    The objective of this research is to investigate the feasibility of utilizing the instantaneous dimensionless frequency (DLF) normalization and Hilbert-Huang Transform (HHT) to characterize the different gear faults in case of variable rotating speed. The normalized DLF of the vibration signals are calculated based on the rotating speed of shaft and the instantaneous frequencies of Intrinsic Mode Functions (IMFs) which are decomposed by Empirical Mode Decomposition (EMD) process. The faulty gear features on DLF-energy distribution of vibration signal can be extracted without the presence of shaft rotating speed, so that the proposed approach can be applied for characterizing the malfunctions of gearbox system under variable shaft rotating speed. A test rig of gear transmission system is performed to illustrate the gear faults, including worn tooth, broken tooth and gear unbalance. Different methods to determine the instantaneous frequency are employed to verify the consistence of characterization results. The DLF-energy distributions of vibration signals are investigated in different faulty gear conditions. The analysis results demonstrate the capability and effectiveness of the proposed approach for characterizing the gear malfunctions at the DLFs corresponding to the meshing frequency as well as the shaft rotating frequency. The support vector machine (SVM) is then employed to classify the vibration patterns of gear transmission system at different malfunctions. Using the energy distribution at the characteristic DLFs as the features, the different fault types of gear can be identified by SVM with high accuracy.

  12. An Ultrahigh Frequency Partial Discharge Signal De-Noising Method Based on a Generalized S-Transform and Module Time-Frequency Matrix

    PubMed Central

    Liu, Yushun; Zhou, Wenjun; Li, Pengfei; Yang, Shuai; Tian, Yan

    2016-01-01

    Due to electromagnetic interference in power substations, the partial discharge (PD) signals detected by ultrahigh frequency (UHF) antenna sensors often contain various background noises, which may hamper high voltage apparatus fault diagnosis and localization. This paper proposes a novel de-noising method based on the generalized S-transform and module time-frequency matrix to suppress noise in UHF PD signals. The sub-matrix maximum module value method is employed to calculate the frequencies and amplitudes of periodic narrowband noise, and suppress noise through the reverse phase cancellation technique. In addition, a singular value decomposition de-noising method is employed to suppress Gaussian white noise in UHF PD signals. Effective singular values are selected by employing the fuzzy c-means clustering method to recover the PD signals. De-noising results of simulated and field detected UHF PD signals prove the feasibility of the proposed method. Compared with four conventional de-noising methods, the results show that the proposed method can suppress background noise in the UHF PD signal effectively, with higher signal-to-noise ratio and less waveform distortion. PMID:27338409

  13. Frequency-specific mechanism links human brain networks for spatial attention.

    PubMed

    Daitch, Amy L; Sharma, Mohit; Roland, Jarod L; Astafiev, Serguei V; Bundy, David T; Gaona, Charles M; Snyder, Abraham Z; Shulman, Gordon L; Leuthardt, Eric C; Corbetta, Maurizio

    2013-11-26

    Selective attention allows us to filter out irrelevant information in the environment and focus neural resources on information relevant to our current goals. Functional brain-imaging studies have identified networks of broadly distributed brain regions that are recruited during different attention processes; however, the dynamics by which these networks enable selection are not well understood. Here, we first used functional MRI to localize dorsal and ventral attention networks in human epileptic subjects undergoing seizure monitoring. We subsequently recorded cortical physiology using subdural electrocorticography during a spatial-attention task to study network dynamics. Attention networks become selectively phase-modulated at low frequencies (δ, θ) during the same task epochs in which they are recruited in functional MRI. This mechanism may alter the excitability of task-relevant regions or their effective connectivity. Furthermore, different attention processes (holding vs. shifting attention) are associated with synchrony at different frequencies, which may minimize unnecessary cross-talk between separate neuronal processes.

  14. Impairment assessment of orthogonal frequency division multiplexing over dispersion-managed links in backbone and backhaul networks

    NASA Astrophysics Data System (ADS)

    Tamilarasan, Ilavarasan; Saminathan, Brindha; Murugappan, Meenakshi

    2016-04-01

    The past decade has seen the phenomenal usage of orthogonal frequency division multiplexing (OFDM) in the wired as well as wireless communication domains, and it is also proposed in the literature as a future proof technique for the implementation of flexible resource allocation in cognitive optical networks. Fiber impairment assessment and adaptive compensation becomes critical in such implementations. A comprehensive analytical model for impairments in OFDM-based fiber links is developed. The proposed model includes the combined impact of laser phase fluctuations, fiber dispersion, self phase modulation, cross phase modulation, four-wave mixing, the nonlinear phase noise due to the interaction of amplified spontaneous emission with fiber nonlinearities, and the photodetector noises. The bit error rate expression for the proposed model is derived based on error vector magnitude estimation. The performance analysis of the proposed model is presented and compared for dispersion compensated and uncompensated backbone/backhaul links. The results suggest that OFDM would perform better for uncompensated links than the compensated links due to the negligible FWM effects and there is a need for flexible compensation. The proposed model can be employed in cognitive optical networks for accurate assessment of fiber-related impairments.

  15. Polymorphic transformation of anhydrous caffeine upon grinding and hydrostatic pressurizing analyzed by low-frequency raman spectroscopy.

    PubMed

    Hédoux, Alain; Guinet, Yannick; Paccou, Laurent; Danède, Florence; Derollez, Patrick

    2013-01-01

    Low-frequency Raman investigations were carried out upon pressurizing and grinding both crystalline forms of anhydrous caffeine at room temperature. These investigations have led to the detection of metastable states under stress. Upon moderated hydrostatic compression, only form I transform into a metastable state characterized by a Raman band-shape resembling that of form II. Above 2 GPa, both pressurized forms convert into an identical disordered state, suggesting a pressure-induced amorphization. In contrast to hydrostatic compression, grinding induces transformation of each phase into the other, leading to an intermediate state only stabilized under long enough grinding. The origin of these metastable states induced by stress was related to the disordered nature of both crystalline forms of caffeine and the stability conditions at room temperature of form I.

  16. Frequency Reuse, Cell Separation, and Capacity Analysis of VHF Digital Link Mode 3 TDMA

    NASA Technical Reports Server (NTRS)

    Shamma, Mohammed A.; Nguyen, Thanh C.; Apaza, Rafael D.

    2003-01-01

    The most recent studies by the Federal Aviation Administration (FAA) and the aviation industry have indicated that it has become increasingly difficult to make new VHF frequency or channel assignments to meet the aviation needs for air-ground communications. FAA has planned for several aggressive improvement measures to the existing systems, but these measures would not meet the projected voice communications needs beyond 2009. FAA found that since 1974 there has been, on the average, a 4 percent annual increase in the number of channel assignments needed to satisfy the air-ground communication traffic (approximately 300 new channel assignments per year). With the planned improvement measures, the channel assignments are expected to reach a maximum number of 16615 channels by about 2010. Hence, the FAA proposed the use of VDL Mode 3 as a new integrated digital voice and data communications systems to meet the future air traffic demand. This paper presents analytical results of frequency reuse; cell separation and capacity estimation of VDL Mode 3 TDMA systems that FAA has planned to implement the future VHF air-ground communications system by the year 2010. For TDMA, it is well understood that the frequency reuse factor is a crucial parameter for capacity estimation. Formulation of this frequency reuse factor is shown, taking into account the limitation imposed by the requirement to have a sufficient Signal to Co-Channel Interference Ratio. Several different values for the Signal to Co-Channel Interference Ratio were utilized corresponding to the current analog VHF DSB-AM systems, and the future digital VDL Mode 3. The required separation of Co-Channel cells is computed for most of the Frequency Protected Service Volumes (FPSV's) currently in use by the FAA. Additionally, the ideal cell capacity for each FPSV is presented. Also, using actual traffic for the Detroit air space, a FPSV traffic distribution model is used to generate a typical cell for channel capacity

  17. Prediction of rain effects on earth-space communication links operating in the 10 to 35 GHz frequency range

    NASA Technical Reports Server (NTRS)

    Stutzman, Warren L.

    1989-01-01

    This paper reviews the effects of precipitation on earth-space communication links operating the 10 to 35 GHz frequency range. Emphasis is on the quantitative prediction of rain attenuation and depolarization. Discussions center on the models developed at Virginia Tech. Comments on other models are included as well as literature references to key works. Also included is the system level modeling for dual polarized communication systems with techniques for calculating antenna and propagation medium effects. Simple models for the calculation of average annual attenuation and cross-polarization discrimination (XPD) are presented. Calculation of worst month statistics are also presented.

  18. High frequency transformers and high Q factor inductors formed using epoxy-based magnetic polymer materials

    DOEpatents

    Sanchez, Robert O.; Gunewardena, Shelton; Masi, James V.

    2005-03-29

    An electrical component in the form of an inductor or transformer is disclosed which includes one or more coils and a magnetic polymer material located near the coils or supporting the coils to provide an electromagnetic interaction therewith. The magnetic polymer material is preferably a cured magnetic epoxy which includes a mercaptan derivative having a ferromagnetic atom chemically bonded therein. The ferromagnetic atom can be either a transition metal or rare-earth atom.

  19. High frequency transformers and high Q factor inductors formed using epoxy-based magnetic polymer materials

    DOEpatents

    Sanchez, Robert O.; Gunewardena, Shelton; Masi, James V.

    2007-11-27

    An electrical component in the form of an inductor or transformer is disclosed which includes one or more coils and a magnetic polymer material located near the coils or supporting the coils to provide an electromagnetic interaction therewith. The magnetic polymer material is preferably a cured magnetic epoxy which includes a mercaptan derivative having a ferromagnetic atom chemically bonded therein. The ferromagnetic atom can be either a transition metal or rare-earth atom.

  20. A Review of Wavelet Transform Time-Frequency Methods for NIRS-Based Analysis of Cerebral Autoregulation.

    PubMed

    Addison, Paul S

    2015-01-01

    Near-infrared spectroscopy (NIRS) has been proposed as a suitable technique for the analysis of cerebral autoregulation as it provides a simpler acquisition methodology and more artifact-free signal. A number of sophisticated wavelet transform methods have recently emerged to quantify the cerebral autoregulation mechanism using NIRS and blood pressure signals. These provide an enhanced partitioning of signal information via the time-frequency plane, which facilitates improved extraction of the components of interest. This area is reviewed, and enhancements to this form of analysis are suggested.

  1. A new concept linking observable stable isotope fractionation to transformation pathways of organic pollutants.

    PubMed

    Elsner, Martin; Zwank, Luc; Hunkeler, Daniel; Schwarzenbach, Rene P

    2005-09-15

    Measuring stable isotope fractionation of carbon, hydrogen, and other elements by Compound Specific Isotope Analysis (CSIA) is a new, innovative approach to assess organic pollutant degradation in the environment. Central to this concept is the Rayleigh equation which relates degradation-induced decreases in concentrations directly to concomitant changes in bulk (= average over the whole compound) isotope ratios. The extent of in situ transformation may therefore be inferred from measured isotope ratios in field samples, provided that an appropriate enrichment factor (epsilonbulk) is known. This epsilonbulk value, however, is usually only valid for a specific compound and for specific degradation conditions. Therefore, a direct comparison of epsilonbulk values for different compounds and for different types of reactions has in general not been feasible. In addition, it is often uncertain how robust and reproducible epsilonbulk values are and how confidently they can be used to quantify contaminant degradation in the field. To improve this situation and to achieve a more in-depth understanding, this critical review aims to relate fundamental insight about kinetic isotope effects (KIE) found in the physico(bio)chemical literature to apparent kinetic isotope effects (AKIE) derived from epsilonbulk values reported in environmentally oriented studies. Starting from basic rate laws, a quite general derivation of the Rayleigh equation is given, resulting in a novel set of simple equations that take into account the effects of (1) nonreacting positions and (2) intramolecular competition and that lead to position-specific AKIE values rather than bulk enrichment factors. Reevaluation of existing epsilonbulk literature values result in consistent ranges of AKIE values that generally are in good agreement with previously published data in the (bio)-chemical literature and are typical of certain degradation reactions (subscripts C and H indicate values for carbon and hydrogen

  2. Hysteresis effects in instantaneous frequency scaling of attenuation on 20 and 30 GHz satellite links

    NASA Technical Reports Server (NTRS)

    Sweeney, D. G.; Pratt, T.; Bostian, C. W.

    1992-01-01

    It has been observed with 20/30 GHz satellite beacon measurements that the ratio of 30 GHz to 20 GHz attenuation changes during some fade events. This ratio displays a hysteresis effect. This effect can be explained by a change in the drop size distribution (DSD) during the event. However, it appears only above approximately 6-8 dB of attenuation at 20 GHz. Instantaneous frequency scaling of attenuation is being proposed as part of an algorithm for uplink power control (ULPC) and the dynamic range of such an algorithm must be appropriately limited to avoid the hysteresis.

  3. Spherical Geodetic Transformations. Volume 2. Catalog of Explicit Representations in the Spatial and Frequency Domains

    DTIC Science & Technology

    1978-09-01

    document. The input is assumed to be known every- such as Heiskanen -Moritz (1967) 1-2 where on the surface of the sphere, and the output is calculated at a...diagrams are described in Section 2 of Volume I of this document. such as Heiskanen -Moritz (1967) 1-3 Kernel: Under this heading appears the spherical...cos ’) (r -2Rr cos ’P + R ) I (E REFERENCES: Heiskanen -Moritz, page 35, equation 1-89. REMARKS: 2-5 TRANSFORMATION: IDENTITY, DELTA FUNCTION Input

  4. X-Linked Agammagobulinemia in a Large Series of North African Patients: Frequency, Clinical Features and Novel BTK Mutations.

    PubMed

    Aadam, Zahra; Kechout, Nadia; Barakat, Abdelhamid; Chan, Koon-Wing; Ben-Ali, Meriem; Ben-Mustapha, Imen; Zidi, Fethi; Ailal, Fatima; Attal, Nabila; Doudou, Fatouma; Abbadi, Mohamed-Cherif; Kaddache, Chawki; Smati, Leila; Touri, Nabila; Chemli, Jalel; Gargah, Tahar; Brini, Ines; Bakhchane, Amina; Charoute, Hicham; Jeddane, Leila; El Atiqi, Sara; El Hafidi, Naïma; Hida, Mustapha; Saile, Rachid; Alj, Hanane Salih; Boukari, Rachida; Bejaoui, Mohamed; Najib, Jilali; Barbouche, Mohamed-Ridha; Lau, Yu-Lung; Mellouli, Fethi; Bousfiha, Ahmed Aziz

    2016-04-01

    X-linked agammagobulinemia (XLA) is a primary immunodeficiency caused by Bruton's tyrosine kinase (BTK) gene defect. XLA patients have absent or reduced number of peripheral B cells and a profound deficiency in all immunoglobulin isotypes. This multicenter study reports the clinical, immunological and molecular features of Bruton's disease in 40 North African male patients. Fifty male out of 63 (male and female) patients diagnosed with serum agammaglobulinemia and non detectable to less than 2% peripheral B cells were enrolled. The search for BTK gene mutations was performed for all of them by genomic DNA amplification and Sanger sequencing. We identified 33 different mutations in the BTK gene in 40 patients including 12 missense mutations, 6 nonsense mutations, 6 splice-site mutations, 5 frameshift, 2 large deletions, one complex mutation and one in-frame deletion. Seventeen of these mutations are novel. This large series shows a lower frequency of XLA among male patients from North Africa with agammaglobulinemia and absent to low B cells compared with other international studies (63.5% vs. 85%). No strong evidence for genotype-phenotype correlation was observed. This study adds to other reports from highly consanguineous North African populations, showing lower frequency of X-linked forms as compared to AR forms of the same primary immunodeficiency. Furthermore, a large number of novel BTK mutations were identified and could further help identify carriers for genetic counseling.

  5. Long-term fire frequency not linked to prehistoric occupations in northern Swedish boreal forest.

    PubMed

    Carcaillet, Christopher; Bergman, Ingela; Delorme, Séverine; Hornberg, Greger; Zackrisson, Olle

    2007-02-01

    Knowledge of past fire regimes is crucial for understanding the changes in fire frequency that are likely to occur during the coming decades as a result of global warming and land-use change. This is a key issue for the sustainable management of forest biodiversity because fire regimes may be controlled by vegetation, human activities, and/or climate. The present paper aims to reconstruct the pattern of fire frequency over the Holocene at three sites located in the same region in the northern Swedish boreal forest. The fire regime is reconstructed from sedimentary charcoal analysis of small lakes or ponds. This method allows fire events to be characterized, after detrending the charcoal influx series, and allows estimation of the time elapsed between fires. The long-term fire regime, in terms of fire-free intervals, can thus be elucidated. At the three sites, the mean fire-free intervals through the Holocene were long and of similar magnitude (approximately 320 years). This similarity suggests that the ecological processes controlling fire ignition and spread were the same. At the three sites, the intervals were shorter before 8600 cal yr BP (calibrated years before present), between 7500 and 4500 cal yr BP, and after 2500 cal yr BP. Geomorphological and vegetation factors cannot explain the observed change, because the three sites are located in the same large ecological region characterized by Pinus sylvestris-Ericaceae mesic forests, established on morainic deposits at the same elevation. Archaeological chronologies also do not match the fire chronologies. A climatic interpretation is therefore the most likely explanation of the long-term regional pattern of fire. Although recent human activities between the 18th and the 20th centuries have clearly affected the fire regime, the dominant factor controlling it for 10000 years in northern Sweden has probably been climatic.

  6. Colony size is linked to paternity frequency and paternity skew in yellowjacket wasps and hornets.

    PubMed

    Loope, Kevin J; Chien, Chun; Juhl, Michael

    2014-12-30

    The puzzle of the selective benefits of multiple mating and multiple paternity in social insects has been a major focus of research in evolutionary biology. We examine paternity in a clade of social insects, the vespine wasps (the yellowjackets and hornets), which contains species with high multiple paternity as well as species with single paternity. This group is particularly useful for comparative analyses given the wide interspecific variation in paternity traits despite similar sociobiology and ecology of the species in the genera Vespula, Dolichovespula and Vespa. We describe the paternity of 5 species of yellowjackets (Vespula spp.) and we perform a phylogenetically controlled comparative analysis of relatedness, paternity frequency, paternity skew, colony size, and nest site across 22 vespine taxa. We found moderate multiple paternity in four small-colony Vespula rufa-group species (effective paternity 1.5 - 2.1), and higher multiple paternity in the large-colony Vespula flavopilosa (effective paternity ~3.1). Our comparative analysis shows that colony size, but not nest site, predicts average intracolony relatedness. Underlying this pattern, we found that greater colony size is associated with both higher paternity frequency and reduced paternity skew. Our results support hypotheses focusing on the enhancement of genetic diversity in species with large colonies, and run counter to the hypothesis that multiple paternity is adaptively maintained due to sperm limitation associated with large colonies. We confirm the patterns observed in taxonomically widespread analyses by comparing closely related species of wasps with similar ecology, behavior and social organization. The vespine wasps may be a useful group for experimental investigation of the benefits of multiple paternity in the future.

  7. Changing air mass frequencies in Canada: potential links and implications for human health.

    PubMed

    Vanos, J K; Cakmak, S

    2014-03-01

    Many individual variables have been studied to understand climate change, yet an overall weather situation involves the consideration of many meteorological variables simultaneously at various times diurnally, seasonally, and yearly. The current study identifies a full weather situation as an air mass type using synoptic scale classification, in 30 population centres throughout Canada. Investigative analysis of long-term air mass frequency trends was completed, drawing comparisons between seasons and climate zones. We find that the changing air mass trends are highly dependent on the season and climate zone being studied, with an overall increase of moderate ('warm') air masses and decrease of polar ('cold') air masses. In the summertime, general increased moisture content is present throughout Canada, consistent with the warming air masses. The moist tropical air mass, containing the most hot and humid air, is found to increase in a statistically significant fashion in the summertime in 46% of the areas studied, which encompass six of Canada's ten largest population centres. This emphasises the need for heat adaptation and acclimatisation for a large proportion of the Canadian population. In addition, strong and significant decreases of transition/frontal passage days were found throughout Canada. This result is one of the most remarkable transition frequency results published to date due to its consistency in identifying declining trends, coinciding with research completed in the United States (US). We discuss relative results and implications to similar US air mass trend analyses, and draw upon research studies involving large-scale upper-level air flow and vortex connections to air mass changes, to small-scale meteorological and air pollution interactions. Further research is warranted to better understand such connections, and how these air masses relate to the overall and city-specific health of Canadians.

  8. Changing air mass frequencies in Canada: potential links and implications for human health

    NASA Astrophysics Data System (ADS)

    Vanos, J. K.; Cakmak, S.

    2014-03-01

    Many individual variables have been studied to understand climate change, yet an overall weather situation involves the consideration of many meteorological variables simultaneously at various times diurnally, seasonally, and yearly. The current study identifies a full weather situation as an air mass type using synoptic scale classification, in 30 population centres throughout Canada. Investigative analysis of long-term air mass frequency trends was completed, drawing comparisons between seasons and climate zones. We find that the changing air mass trends are highly dependent on the season and climate zone being studied, with an overall increase of moderate (`warm') air masses and decrease of polar (`cold') air masses. In the summertime, general increased moisture content is present throughout Canada, consistent with the warming air masses. The moist tropical air mass, containing the most hot and humid air, is found to increase in a statistically significant fashion in the summertime in 46 % of the areas studied, which encompass six of Canada's ten largest population centres. This emphasises the need for heat adaptation and acclimatisation for a large proportion of the Canadian population. In addition, strong and significant decreases of transition/frontal passage days were found throughout Canada. This result is one of the most remarkable transition frequency results published to date due to its consistency in identifying declining trends, coinciding with research completed in the United States (US). We discuss relative results and implications to similar US air mass trend analyses, and draw upon research studies involving large-scale upper-level air flow and vortex connections to air mass changes, to small-scale meteorological and air pollution interactions. Further research is warranted to better understand such connections, and how these air masses relate to the overall and city-specific health of Canadians.

  9. High-Frequency Heart Rate Variability Linked to Affiliation with a New Group

    PubMed Central

    Sahdra, Baljinder K.; Ciarrochi, Joseph; Parker, Philip D.

    2015-01-01

    This study tests the hypothesis that high levels of high-frequency heart rate variability (HF-HRV) predisposes individuals to affiliate with new groups. Resting cardiac physiological recordings were taken before and after experimental sessions to measure trait high-frequency heart rate variability as an index of dispositional autonomic influence on heart rate. Following an experimental manipulation of priming of caring-related words, participants engaged in a minimal group paradigm, in which they imagined being a member of one of two arbitrary groups, allocated money to members of the two groups, and rated their affiliation with the groups. High levels of HF-HRV were associated with ingroup favouritism while allocating money, an effect largely attributable to a positive relationship between HF-HRV and allocation of money to the ingroup, and less due to a negative relationship between HF-HRV and money allocation to the outgroup. HF-HRV was also associated with increased self-reported affiliation feelings for the ingroup but was unrelated to feelings towards the outgroup. These effects remained substantial even after controlling for age, gender, BMI, mood, caffeine consumption, time of day of data collection, smoking and alcohol behaviour, and respiration rate. Further, the effects were observed regardless of whether participants were primed with caring-related words or not. This study is the first to bridge a long history of research on ingroup favouritism to the relatively recent body of research on cardiac vagal tone by uncovering a positive association between HF-HRV and affiliation with a novel group. PMID:26106891

  10. Probabilistic flood inundation mapping of ungauged rivers: Linking GIS techniques and frequency analysis

    NASA Astrophysics Data System (ADS)

    Sarhadi, Ali; Soltani, Saeed; Modarres, Reza

    2012-08-01

    SummaryThis study presents an exhaustive methodology of floodplain mapping at ungauged rivers. To present our methodology, we selected the Halilrud basin and Jiroft city in southeastern Iran as an example of hazardous regions. To estimate flood quantiles in different return periods at ungauged reaches, we used regional flood frequency analysis. By using the well-known L-moments approach and related criteria, a homogeneous region was formed and the 3-parameter Log normal distribution was identified as the robust regional frequency distribution. The hydro-geomorphic characteristics and the land use properties of the catchments were then extracted using RS&GIS techniques to establish multivariate regional regression models between hydro-geomorphic characteristics and flood quantiles. After delineation of the catchments for the ungauged reaches, flood quantiles as an important factor in flood inundation at outlets of these reaches with different probabilities were estimated using the regional regression models. To delineate flood hazard maps and to enhance the accuracy of the hydraulic modeling, we applied satellite stereoscope images of Cartosat-1 along with the Rational Polynomial Coefficients to extract a high resolution DTM and detailed parameterization of the channel required by 1D hydraulic model HEC-RAS. The GIS-based HEC-Geo RAS pre- and post-processor were also used for careful optimization of the geometry features for real visualization of the flood prone areas. Information of some historical flood events was also used to evaluate the hydraulic model performance in predicting flood inundations. Finally, vulnerable areas were crossed with extracted land use mapping from IRS-P6 satellite images to differentiate the critical infrastructures and the valuable land use classes affected by floods in different return periods.

  11. Increased Frequency of Spontaneous Neoplastic Transformation in Progeny of Bystander Cells from Cultures Exposed to Densely Ionizing Radiation

    PubMed Central

    Buonanno, Manuela; de Toledo, Sonia M.; Azzam, Edouard I.

    2011-01-01

    An increased risk of carcinogenesis caused by exposure to space radiation during prolonged space travel is a limiting factor for human space exploration. Typically, astronauts are exposed to low fluences of ionizing particles that target only a few cells in a tissue at any one time. The propagation of stressful effects from irradiated to neighboring bystander cells and their transmission to progeny cells would be of importance in estimates of the health risks of exposure to space radiation. With relevance to the risk of carcinogenesis, we investigated, in model C3H 10T½ mouse embryo fibroblasts (MEFs), modulation of the spontaneous frequency of neoplastic transformation in the progeny of bystander MEFs that had been in co-culture 10 population doublings earlier with MEFs exposed to moderate doses of densely ionizing iron ions (1 GeV/nucleon) or sparsely ionizing protons (1 GeV). An increase (P<0.05) in neoplastic transformation frequency, likely mediated by intercellular communication through gap junctions, was observed in the progeny of bystander cells that had been in co-culture with cells irradiated with iron ions, but not with protons. PMID:21738697

  12. Ultra-Wideband Indoor Double-Directional Channel Estimation Using Transformation between Frequency and Time Domain Signals

    NASA Astrophysics Data System (ADS)

    Iwakiri, Naohiko; Kobayashi, Takehiko

    This paper proposes an ultra-wideband double-directional spatio-temporal channel sounding technique using transformation between frequency- and time-domain (FD and TD) signals. Virtual antenna arrays, composed of omnidirectional antennas and scanners, are used for transmission and reception in the FD. After Fourier transforming the received FD signals to TD ones, time of arrival (TOA) is estimated using a peak search over the TD signals, and then angle of arrivals (AOA) and angle of departure (AOD) are estimated using a weighted angle histogram with a multiple signal classification (MUSIC) algorithm applied to the FD signals, inverse-Fourier transformed from the TD signals divided into subregions. Indoor channel sounding results validated that an appropriate weighting reduced a spurious level in the angle histogram by a factor of 0.1 to 0.2 in comparison with that of non-weighting. The proposed technique successfully resolved dominant multipath components, including a direct path, a single reflection, and a single diffraction, in line-of-sight (LOS) and non-LOS environments. Joint TOA and AOA/AOD spectra were also derived from the sounding signals. The spectra illustrated the dominant multipath components (agreed with the prediction by ray tracing) as clusters.

  13. A new high-frequency Agrobacterium-mediated transformation technique for Sesamum indicum L. using de-embryonated cotyledon as explant.

    PubMed

    Chowdhury, Supriyo; Basu, Arpita; Kundu, Surekha

    2014-09-01

    In spite of the economic importance of sesame (Sesamum indicum L.) and the recent availability of its genome sequence, a high-frequency transformation protocol is still not available. The only two existing Agrobacterium-mediated transformation protocols that are available have poor transformation efficiencies of less than 2%. In the present study, we report a high-frequency, simple, and reproducible transformation protocol for sesame. Transformation was done using de-embryonated cotyledons via somatic embryogenic stages. All the critical parameters of transformation, like incubation period of explants in pre-regeneration medium prior to infection by Agrobacterium tumefaciens, cocultivation period, concentrations of acetosyringone in cocultivation medium, kanamycin concentration, and concentration of plant hormones, including 6-benzylaminopurine, have been optimized. This protocol is superior to the two existing protocols in its high regeneration and transformation efficiencies. The transformed sesame lines have been tested by PCR, RT-PCR for neomycin phosphotransferase II gene expression, and β-glucuronidase (GUS) assay. The regeneration frequency and transformation efficiency are 57.33 and 42.66%, respectively. T0 and T1 generation transgenic plants were analyzed, and several T1 plants homozygous for the transgenes were obtained.

  14. Successful non-native speech perception is linked to frequency following response phase consistency.

    PubMed

    Omote, Akihiro; Jasmin, Kyle; Tierney, Adam

    2017-08-01

    Some people who attempt to learn a second language in adulthood meet with greater success than others. The causes driving these individual differences in second language learning skill continue to be debated. In particular, it remains controversial whether robust auditory perception can provide an advantage for non-native speech perception. Here, we tested English speech perception in native Japanese speakers through the use of frequency following responses, the evoked gamma band response, and behavioral measurements. Participants whose neural responses featured less timing jitter from trial to trial performed better on perception of English consonants than participants with more variable neural timing. Moreover, this neural metric predicted consonant perception to a greater extent than did age of arrival and length of residence in the UK, and neural jitter predicted independent variance in consonant perception after these demographic variables were accounted for. Thus, difficulties with auditory perception may be one source of problems learning second languages in adulthood. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. History of reading struggles linked to enhanced learning in low spatial frequency scenes.

    PubMed

    Schneps, Matthew H; Brockmole, James R; Sonnert, Gerhard; Pomplun, Marc

    2012-01-01

    People with dyslexia, who face lifelong struggles with reading, exhibit numerous associated low-level sensory deficits including deficits in focal attention. Countering this, studies have shown that struggling readers outperform typical readers in some visual tasks that integrate distributed information across an expanse. Though such abilities would be expected to facilitate scene memory, prior investigations using the contextual cueing paradigm failed to find corresponding advantages in dyslexia. We suggest that these studies were confounded by task-dependent effects exaggerating known focal attention deficits in dyslexia, and that, if natural scenes were used as the context, advantages would emerge. Here, we investigate this hypothesis by comparing college students with histories of severe lifelong reading difficulties (SR) and typical readers (TR) in contexts that vary attention load. We find no differences in contextual-cueing when spatial contexts are letter-like objects, or when contexts are natural scenes. However, the SR group significantly outperforms the TR group when contexts are low-pass filtered natural scenes [F(3, 39) = 3.15, p<.05]. These findings suggest that perception or memory for low spatial frequency components in scenes is enhanced in dyslexia. These findings are important because they suggest strengths for spatial learning in a population otherwise impaired, carrying implications for the education and support of students who face challenges in school.

  16. Precision measurement of the hydrogen 1S-2S frequency via a 920-km fiber link.

    PubMed

    Matveev, Arthur; Parthey, Christian G; Predehl, Katharina; Alnis, Janis; Beyer, Axel; Holzwarth, Ronald; Udem, Thomas; Wilken, Tobias; Kolachevsky, Nikolai; Abgrall, Michel; Rovera, Daniele; Salomon, Christophe; Laurent, Philippe; Grosche, Gesine; Terra, Osama; Legero, Thomas; Schnatz, Harald; Weyers, Stefan; Altschul, Brett; Hänsch, Theodor W

    2013-06-07

    We have measured the frequency of the extremely narrow 1S-2S two-photon transition in atomic hydrogen using a remote cesium fountain clock with the help of a 920 km stabilized optical fiber. With an improved detection method we obtain f(1S-2S)=2466 061 413 187 018 (11)  Hz with a relative uncertainty of 4.5×10(-15), confirming our previous measurement obtained with a local cesium clock [C. G. Parthey et al., Phys. Rev. Lett. 107, 203001 (2011)]. Combining these results with older measurements, we constrain the linear combinations of Lorentz boost symmetry violation parameters c((TX))=(3.1±1.9)×10(-11) and 0.92c((TY))+0.40c((TZ))=(2.6±5.3)×10(-11) in the standard model extension framework [D. Colladay, V. A. Kostelecký, Phys. Rev. D. 58, 116002 (1998)].

  17. History of Reading Struggles Linked to Enhanced Learning in Low Spatial Frequency Scenes

    PubMed Central

    Schneps, Matthew H.; Brockmole, James R.; Sonnert, Gerhard; Pomplun, Marc

    2012-01-01

    People with dyslexia, who face lifelong struggles with reading, exhibit numerous associated low-level sensory deficits including deficits in focal attention. Countering this, studies have shown that struggling readers outperform typical readers in some visual tasks that integrate distributed information across an expanse. Though such abilities would be expected to facilitate scene memory, prior investigations using the contextual cueing paradigm failed to find corresponding advantages in dyslexia. We suggest that these studies were confounded by task-dependent effects exaggerating known focal attention deficits in dyslexia, and that, if natural scenes were used as the context, advantages would emerge. Here, we investigate this hypothesis by comparing college students with histories of severe lifelong reading difficulties (SR) and typical readers (TR) in contexts that vary attention load. We find no differences in contextual-cueing when spatial contexts are letter-like objects, or when contexts are natural scenes. However, the SR group significantly outperforms the TR group when contexts are low-pass filtered natural scenes [F(3, 39) = 3.15, p<.05]. These findings suggest that perception or memory for low spatial frequency components in scenes is enhanced in dyslexia. These findings are important because they suggest strengths for spatial learning in a population otherwise impaired, carrying implications for the education and support of students who face challenges in school. PMID:22558210

  18. Frequency Weighted Discrete-Time Controller Order Reduction Using Bilinear Transformation

    NASA Astrophysics Data System (ADS)

    Karimaghaee, Paknosh; Noroozi, Navid

    2011-01-01

    This paper addresses a new method for order reduction of linear time invariant discrete-time controller. This method leads to a new algorithm for controller reduction when a discrete time controller is used to control a continuous time plant. In this algorithm, at first, a full order controller is designed in s-plane. Then, bilinear transformation is applied to map the closed loop system to z-plane. Next, new closed loop controllability and observability grammians are calculated in z-plane. Finally, balanced truncation idea is used to reduce the order of controller. The stability property of the reduced order controller is discussed. To verify the effectiveness of our method, a reduced controller is designed for four discs system.

  19. White light-emitting diode based wireless orthogonal frequency division multiplexing link with improved transmission capacity using Bayesian compressive sensing

    NASA Astrophysics Data System (ADS)

    Won, Yong-Yuk; Seo, Dong-Sun; Yoon, Sang Min

    2016-04-01

    We propose a technique that improves the channel capacity of an optical wireless orthogonal frequency division multiplexing (OFDM) transmission, which employs a visible light-emitting diode. An OFDM waveform encoded by quadrature phase shift keying (QPSK) or 16-quadrature amplitude modulation is compressed and then transformed into a sparse waveform using a proposed advanced systematic sampling. At the optical wireless receiver, the original waveform is recovered by L1-minimization based on a Bayesian compressive sensing. Our experimental results show the significant increase in the channel capacity from 31.12 to 51.87 Mbit/s at forward error correction limit (i.e., error vector magnitude of 32%) in case of QPSK symbols.

  20. De-striping hyperspectral imagery using wavelet transform and adaptive frequency domain filtering

    NASA Astrophysics Data System (ADS)

    Pande-Chhetri, Roshan; Abd-Elrahman, Amr

    2011-09-01

    Hyperspectral imagers are built line-by-line similar to images acquired by pushbroom sensors. They can experience striping artifacts due to variations in detector response to incident imagery. In this research, a method for hyperspectral image de-striping based on wavelet analysis and adaptive Fourier zero-frequency amplitude normalization has been developed. The algorithm was tested against three other de-striping algorithms. Hyperspectral image bands of different scenes with significant striping and random noise, as well as an image with simulated noise, were used in the testing. The results were assessed visually and quantitatively using frequency domain Signal-to-Noise Ratio (SNR), Root Mean Square Error (RMSE) and/or Peak Signal-to-Ratio (PSNR). The results demonstrated the superiority of our proposed algorithm in de-striping hyperspectral images without introducing unwanted artifacts, yet preserving image details. In the noise-induced image results, the proposed method reduced RMSE error and improved PSNR by 3.5 dB which is better than other tested methods. A Combined method, integrating the proposed algorithm with a generic wavelet-based de-noising algorithm, showed significant random noise suppression in addition to stripe reduction with a PSNR value of 4.3 dB. These findings make the algorithm a candidate for practical implementation on remote sensing images including high resolution hyperspectral images contaminated with stripe and random noise.

  1. Focusing vibrating targets in frequency-modulation continuous-wave-synthetic aperture radar with Doppler keystone transform

    NASA Astrophysics Data System (ADS)

    Hu, Yuxin; Zhang, Yuan; Sun, Jinping; Lei, Peng

    2016-04-01

    Vibrating targets generally induce sinusoidal micro-Doppler modulation in high resolution synthetic aperture radar (SAR). They could cause defocused and ghost results by conventional imaging algorithms. This paper proposes a method on vibrating target imaging in frequency-modulation continuous-wave (FMCW) SAR systems. The continuous motion of sensor platform during pulse time is considered in the signal model. Based on Bessel series expansion of the signal in the azimuth direction, the influence of platform motion on the azimuth frequency is eliminated after dechirp and deskew. In addition, the range walk is compensated in the two-dimensional frequency domain by Doppler keystone transform. Next, using range cell migration correction, the azimuth quadratic phase compensation and the range curvature correction are made in range-Doppler domain for the focus of paired echoes. The residual video phase of paired echoes is eliminated, and vibration parameters are estimated to compensate in the sinusoidal modulation phase. Then the deghosted image of vibrating targets can be obtained. The proposed method is applicable to multiple targets with various vibrating states due to no need of a priori knowledge of targets. Finally, simulations are carried out to validate the effectiveness of the method in FMCW-SAR imaging of vibrating targets.

  2. Homeodomain Protein Transforming Growth Factor Beta-Induced Factor 2 Like, X-Linked Function in Colon Adenocarcinoma Cells

    PubMed

    Akbari, Abolfazl; Agah, Shahram; Heidari, Mansour; Mobini, Gholam Reza; Faghihloo, Ebrahim; Sarveazad, Arash; Mirzaei, Alireza

    2017-08-27

    Background: TGIF2LX (transforming growth factor beta-induced factor 2 like, X-linked) is a homeodomain (HD) protein that has been implicated in the negative regulation of cell signaling pathways. The aim of this study was to investigate the possible functions of TGIF2LX in colon adenocarcinoma cells. Methods: The human SW48 cell line was transfected with cDNA for the wild-type TGIF2LX gene and gene/protein over-expression was confirmed by microscopic analysis, real time RT-PCR and Western blotting techniques. In vitro cell proliferation was evaluated by MTT and BrdU assays. After developing a colon tumor model in nude mice, immunohistochemical (IHC) staining of tumor tissue was carried out for Ki-67 (proliferation) and CD34 (angiogenesis) markers. To predict potential protein partners of TGIF2LX, in-silico analysis was also conducted. Results: Obtained results showed over-expression of TGIF2LX as a potential transcription factor could inhibit either proliferation or angiogenesis (P<0.05) in colon tumors. In-silico results predicted interaction of TGIF2LX with other proteins considered important for cellular development. Conclusions: Our findings provided evidence of molecular mechanisms by which TGIF2LX could act as a tumor suppressor in colon adenocarcinoma cells. Thus, this gene may potentially be a promising option for colon cancer gene-based therapeutic strategies. Creative Commons Attribution License

  3. Construction of a low-frequency high-power piezoelectric transformer with a specified step-up voltage transformation ratio using two identical bolt-clamped Langevin-type transducers

    NASA Astrophysics Data System (ADS)

    Adachi, Kazunari; Konno, Takuma; Kosugi, Satoshi

    2015-06-01

    We propose a low-frequency piezoelectric transformer comprising two identical bolt-clamped Langevin-type transducers (BLTs) and a stepped horn with a half-wavelength straight extension. The transformer can realize a specified step-up voltage transformation ratio as determined by the cross-sectional area ratio of the horn whose both ends the two BLTs are connected to, and the driving frequency at which the specified transformation ratio is realized can be set near its mechanical resonance. Thus, it can be mechanically held firmly at its vibratory node without affecting the mechanical vibration mode or resulting in a loss of energy. After relevant finite-element simulations, experiments were conducted for a trial-fabricated transformer of the above type. As a result, the experimental results predicted by the simulations were obtained in step-up operation. The influence of the load resistance on the deviation of the driving frequency from its total mechanical resonance of 53.1 kHz was found to be less than 130 Hz (0.24% of the resonance frequency) only. High-power performance of the piezoelectric transformer was also demonstrated.

  4. Nonuniform fast Fourier transform-based fast back-projection algorithm for stepped frequency continuous wave ground penetrating radar imaging

    NASA Astrophysics Data System (ADS)

    Qu, Lele; Yin, Yuqing

    2016-10-01

    Stepped frequency continuous wave ground penetrating radar (SFCW-GPR) systems are becoming increasingly popular in the GPR community due to the wider dynamic range and higher immunity to radio interference. The traditional back-projection (BP) algorithm is preferable for SFCW-GPR imaging in layered mediums scenarios for its convenience and robustness. However, the existing BP imaging algorithms are usually very computationally intensive, which limits their practical applications to SFCW-GPR imaging. To solve the above problem, a fast SFCW-GPR BP imaging algorithm based on nonuniform fast Fourier transform (NUFFT) technique is proposed in this paper. By reformulating the traditional BP imaging algorithm into the evaluations of NUFFT, the computational efficiency of NUFFT is exploited to reduce the computational complexity of the imaging reconstruction. Both simulation and experimental results have verified the effectiveness and improvement of computational efficiency of the proposed imaging method.

  5. Study of human neurovegetative and hematologic effects of environmental low-frequency (50-Hz) electromagnetic fields produced by transformers.

    PubMed

    Bonhomme-Faivre, L; Marion, S; Bezie, Y; Auclair, H; Fredj, G; Hommeau, C

    1998-01-01

    A survey of neurovegetative and hematologic disorders was conducted in a population (n = 13) exposed occupationally to environmental electromagnetic fields; the population was matched with 13 control subjects. The exposed subjects worked at least 8 h/d for 1-5 y in premises located above transformers and high-tension cables, and the subjects were submitted to low-frequency electromagnetic fields (i.e., 50 Hz) of 0.2 microT-6.6 microT. The subjects were matched with respect to socioeconomic category, sex, and age with a control population of subjects that worked in premises outside of the immediate vicinity of transformers or high-tension cables. The exposed population had a significant increase in degree of certain neurovegetative disorders (i.e., physical fatigue, psychical asthenia, lipothymia, decreased libido, melancholy, depressive tendency, and irritability). In addition, the population experienced a significant fall in total lymphocytes and CD4, CD3, and CD2 lymphocytes, as well as a rise in NK cells. Leukopenia and neutropenia were also observed in two persons permanently exposed to doses of 1.2-6.6 microT. The disorders disappeared when exposure stopped, and they reappeared on reexposure.

  6. Optimized discrete wavelet transforms in the cubed sphere with the lifting scheme—implications for global finite-frequency tomography

    NASA Astrophysics Data System (ADS)

    Chevrot, Sébastien; Martin, Roland; Komatitsch, Dimitri

    2012-12-01

    Wavelets are extremely powerful to compress the information contained in finite-frequency sensitivity kernels and tomographic models. This interesting property opens the perspective of reducing the size of global tomographic inverse problems by one to two orders of magnitude. However, introducing wavelets into global tomographic problems raises the problem of computing fast wavelet transforms in spherical geometry. Using a Cartesian cubed sphere mapping, which grids the surface of the sphere with six blocks or 'chunks', we define a new algorithm to implement fast wavelet transforms with the lifting scheme. This algorithm is simple and flexible, and can handle any family of discrete orthogonal or bi-orthogonal wavelets. Since wavelet coefficients are local in space and scale, aliasing effects resulting from a parametrization with global functions such as spherical harmonics are avoided. The sparsity of tomographic models expanded in wavelet bases implies that it is possible to exploit the power of compressed sensing to retrieve Earth's internal structures optimally. This approach involves minimizing a combination of a ℓ2 norm for data residuals and a ℓ1 norm for model wavelet coefficients, which can be achieved through relatively minor modifications of the algorithms that are currently used to solve the tomographic inverse problem.

  7. On Hilbert-Huang Transform Based Synthesis of a Signal Contaminated by Radio Frequency Interference or Fringes

    NASA Technical Reports Server (NTRS)

    Kizhner, Semion; Shiri, Ron S.; Vootukuru, Meg; Coletti, Alessandro

    2015-01-01

    Norden E. Huang et al. had proposed and published the Hilbert-Huang Transform (HHT) concept correspondently in 1996, 1998. The HHT is a novel method for adaptive spectral analysis of non-linear and non-stationary signals. The HHT comprises two components: - the Huang Empirical Mode Decomposition (EMD), resulting in an adaptive data-derived basis of Intrinsic Mode functions (IMFs), and the Hilbert Spectral Analysis (HSA1) based on the Hilbert Transform for 1-dimension (1D) applied to the EMD IMF's outcome. Although paper describes the HHT concept in great depth, it does not contain all needed methodology to implement the HHT computer code. In 2004, Semion Kizhner and Karin Blank implemented the reference digital HHT real-time data processing system for 1D (HHT-DPS Version 1.4). The case for 2-Dimension (2D) (HHT2) proved to be difficult due to the computational complexity of EMD for 2D (EMD2) and absence of a suitable Hilbert Transform for 2D spectral analysis (HSA2). The real-time EMD2 and HSA2 comprise the real-time HHT2. Kizhner completed the real-time EMD2 and the HSA2 reference digital implementations respectively in 2013 & 2014. Still, the HHT2 outcome synthesis remains an active research area. This paper presents the initial concepts and preliminary results of HHT2-based synthesis and its application to processing of signals contaminated by Radio-Frequency Interference (RFI), as well as optical systems' fringe detection and mitigation at design stage. The Soil Moisture Active Passive (SMAP mission (SMAP) carries a radiometer instrument that measures Earth soil moisture at L1 frequency (1.4 GHz polarimetric - H, V, 3rd and 4th Stokes parameters). There is abundant RFI at L1 and because soil moisture is a strategic parameter, it is important to be able to recover the RFI-contaminated measurement samples (15% of telemetry). State-of-the-art only allows RFI detection and removes RFI-contaminated measurements. The HHT-based analysis and synthesis facilitates

  8. A new method of detecting micro-calcification clusters in mammograms using contourlet transform and non-linking simplified PCNN.

    PubMed

    Guo, Ya'nan; Dong, Min; Yang, Zhen; Gao, Xiaoli; Wang, Keju; Luo, Chongfan; Ma, Yide; Zhang, Jiuwen

    2016-07-01

    Mammography analysis is an effective technology for early detection of breast cancer. Micro-calcification clusters (MCs) are a vital indicator of breast cancer, so detection of MCs plays an important role in computer aided detection (CAD) system, this paper proposes a new hybrid method to improve MCs detection rate in mammograms. The proposed method comprises three main steps: firstly, remove label and pectoral muscle adopting the largest connected region marking and region growing method, and enhance MCs using the combination of double top-hat transform and grayscale-adjustment function; secondly, remove noise and other interference information, and retain the significant information by modifying the contourlet coefficients using nonlinear function; thirdly, we use the non-linking simplified pulse-coupled neural network to detect MCs. In our work, we choose 118 mammograms including 38 mammograms with micro-calcification clusters and 80 mammograms without micro-calcification to demonstrate our algorithm separately from two open and common database including the MIAS and JSMIT; and we achieve the higher specificity of 94.7%, sensitivity of 96.3%, AUC of 97.0%, accuracy of 95.8%, MCC of 90.4%, MCC-PS of 61.3% and CEI of 53.5%, these promising results clearly demonstrate that the proposed approach outperforms the current state-of-the-art algorithms. In addition, this method is verified on the 20 mammograms from the People's Hospital of Gansu Province, the detection results reveal that our method can accurately detect the calcifications in clinical application. This proposed method is simple and fast, furthermore it can achieve high detection rate, it could be considered used in CAD systems to assist the physicians for breast cancer diagnosis in the future. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Cryptographic Unification of Mass and Space Links Neutrino Flavor (νe/νμ) Transformations with the Cosmological Constant Λ

    NASA Astrophysics Data System (ADS)

    Dai, Yang; Borisov, Alex B.; Longworth, James W.; Boyer, Keith; Rhodes, Charles K.

    The universe exhibits two striking manifestations, (a) immense complexity and (b) an astonishingly high scale-free precision. Since a cryptographic system based on the modular arithmetic of a finite field can provide a mathematical structure matching these two cardinal characteristics, it is natural to evaluate the theoretical possibilities of a cryptographic analysis of physical phenomena. The organization of the particle mass scale provides a particularly suitable test of this idea, since the cryptographic approach also has the inherent feature that divergences are fully barred, thereby eliminating the need for ad hoc procedures of renormalization. This article (1) shows how such a cryptographic concept can be implemented and (2) demonstrates its surprising ability to synthesize the description of a broad range of phenomena through the development of an interlocking set of quantitative findings. It is found that a cryptographic theoretical framework based solely on two physically anchored parameters, a modulus Pα and a corresponding primitive root gα, can simultaneously achieve six goals. Specifically, it (α) unites the concepts of mass and space, (β) organizes the physical mass scale in a group structure, (γ) produces a quantitative concordance of findings linking the cosmic and micro-scales that includes values for the fine structure constant α and the unified strong-electroweak coupling constant α*, (δ) respectively gives prospective magnitudes of 0.808 meV and 27.68 meV for the rest masses mνe and mνμ of the electron (νe) and muon (νμ) neutrinos, (ɛ) specifies a symmetry condition that yields an exact predicted value for the Higgs particle mass that lies above 1018 GeV, and (ζ) enables the formulation of a direct physical connection between the anomalous flavor (νe/νμ) transforming propagation of solar neutrinos and the existence of a positive cosmological constant Λ. These results are uniformly in agreement with all corresponding

  10. Integrin-linked kinase mediates the hydrogen peroxide-dependent transforming growth factor-β1 up-regulation.

    PubMed

    Gonzalez-Ramos, M; de Frutos, S; Griera, M; Luengo, A; Olmos, G; Rodriguez-Puyol, D; Calleros, L; Rodriguez-Puyol, M

    2013-08-01

    Transforming growth factor type-β1 (TGF-β1) has been recognized as a central mediator in many pathological events related to extracellular matrix (ECM) proteins accumulation, where their locally increased expression has been implicated in the fibrosis process of numerous organs, including glomerular fibrosis in the kidney. We and others have reported the TGF-β1 synthesis regulation by reactive oxygen species (ROS), and moreover we also described the implication of integrin-linked kinase (ILK) in the AP-1-dependent TGF-β1 up-regulation. Thus, we propose here that hydrogen peroxide (H2O2)-dependent TGF-β1 regulation may be mediated by ILK activation. First we confirmed the increase in TGF-β1 expression in human mesangial cells (HMC) after treatment with H2O2 or with an alternative H2O2-generating system such as the glucose-oxidase enzyme (GOX). By using immunoblotting, immunofluorescence, and ELISA techniques, we demonstrate that extracellular H2O2 up-regulates TGF-β1 transcription, as well as increases TGF-β1 promoter activity. Furthermore, catalase-decreased intracellular H2O2 abolished TGF-β1 up-regulation. The use of pharmacological inhibitors as well as knockdown of ILK with small interfering RNA (siRNA) demonstrated the implication of a PI3K/ILK/AKT/ERK MAPK signaling pathway axis in the H2O2-induced TGF-β1 overexpression. Finally, we explored the physiological relevance of these findings by treating HMC with angiotensin II, a known stimuli of H2O2 synthesis. Our results confirm the relevance of previous findings after a more physiological stimulus. In summary, our results provide evidence that ILK activity changes may act as a mechanism in response to different stimuli such as H2O2 in the induced TGF-β1 up-regulation in pathological or even physiological conditions.

  11. Fundamental frequency during couple conflict: an analysis of physiological, behavioral, and sex-linked information encoded in vocal expression.

    PubMed

    Weusthoff, Sarah; Baucom, Brian R; Hahlweg, Kurt

    2013-04-01

    The human voice is one of the sounds most frequently experienced by human beings. During couple conflict, higher fundamental frequency (f0), a physical property of human speech, has been linked to an increased risk of divorce, less beneficial response to couple therapy, and higher levels of dysfunctional communication behavior. F0 is generally considered to be a measure of emotional arousal, but it is not currently clear whether this interpretation is appropriate for understanding spouses' f0 during couple interaction. The goal of the current article is to clarify what forms of information are encoded in f0 during couple conflict by examining the relations between f0 range, physiological variables, and communication behavior during the conflict discussions of 67 German couples. In line with evolutionary models of speech production, associations emerged in the expected directions between f0 and: (a) physiological variables (e.g., heart rate, blood pressure, and cortisol); (b) self-reported communication behavior; and (c) observationally coded communication behavior. Additionally, simultaneous examination of physiological variables and observationally coded communication behaviors revealed that associations between both sets of variables and f0 range were largely independent of one another. Furthermore, women's range of f0 was significantly greater than men's range of f0. With regard to social signaling theories, f0 range can be understood as a nonverbal transmission of distress. Implications for future research on and use of f0 are discussed. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

  12. Pairing high-frequency data with a link-node model to manage dissolved oxygen impairment in a dredged estuary.

    PubMed

    Camarillo, Mary Kay; Weissmann, Gregory A; Gulati, Shelly; Herr, Joel; Sheeder, Scott; Stringfellow, William T

    2016-08-01

    High-frequency data and a link-node model were used to investigate the relative importance of mass loads of oxygen-demanding substances and channel geometry on recurrent low dissolved oxygen (DO) in the San Joaquin River Estuary in California. The model was calibrated using 6 years of data. The calibrated model was then used to determine the significance of the following factors on low DO: excavation of the river to allow navigation of large vessels, non-point source pollution from the agricultural watershed, effluent from a wastewater treatment plant, and non-point source pollution from an urban area. An alternative metric for low DO, excess net oxygen demand (ENOD), was applied to better characterize DO impairment. Model results indicate that the dredged ship channel had the most significant effect on DO (62 % fewer predicted hourly DO violations), followed by mass load inputs from the watershed (52 % fewer predicted hourly DO violations). Model results suggest that elimination of any one factor will not completely resolve DO impairment and that continued use of supplemental aeration is warranted. Calculation of ENOD proved more informative than the sole use of DO. Application of the simple model allowed for interpretation of the extensive data collected. The current monitoring program could be enhanced by additional monitoring stations that would provide better volumetric estimates of low DO.

  13. A Novel Characteristic Frequency Bands Extraction Method for Automatic Bearing Fault Diagnosis Based on Hilbert Huang Transform

    PubMed Central

    Yu, Xiao; Ding, Enjie; Chen, Chunxu; Liu, Xiaoming; Li, Li

    2015-01-01

    Because roller element bearings (REBs) failures cause unexpected machinery breakdowns, their fault diagnosis has attracted considerable research attention. Established fault feature extraction methods focus on statistical characteristics of the vibration signal, which is an approach that loses sight of the continuous waveform features. Considering this weakness, this article proposes a novel feature extraction method for frequency bands, named Window Marginal Spectrum Clustering (WMSC) to select salient features from the marginal spectrum of vibration signals by Hilbert–Huang Transform (HHT). In WMSC, a sliding window is used to divide an entire HHT marginal spectrum (HMS) into window spectrums, following which Rand Index (RI) criterion of clustering method is used to evaluate each window. The windows returning higher RI values are selected to construct characteristic frequency bands (CFBs). Next, a hybrid REBs fault diagnosis is constructed, termed by its elements, HHT-WMSC-SVM (support vector machines). The effectiveness of HHT-WMSC-SVM is validated by running series of experiments on REBs defect datasets from the Bearing Data Center of Case Western Reserve University (CWRU). The said test results evidence three major advantages of the novel method. First, the fault classification accuracy of the HHT-WMSC-SVM model is higher than that of HHT-SVM and ST-SVM, which is a method that combines statistical characteristics with SVM. Second, with Gauss white noise added to the original REBs defect dataset, the HHT-WMSC-SVM model maintains high classification accuracy, while the classification accuracy of ST-SVM and HHT-SVM models are significantly reduced. Third, fault classification accuracy by HHT-WMSC-SVM can exceed 95% under a Pmin range of 500–800 and a m range of 50–300 for REBs defect dataset, adding Gauss white noise at Signal Noise Ratio (SNR) = 5. Experimental results indicate that the proposed WMSC method yields a high REBs fault classification accuracy

  14. A Novel Characteristic Frequency Bands Extraction Method for Automatic Bearing Fault Diagnosis Based on Hilbert Huang Transform.

    PubMed

    Yu, Xiao; Ding, Enjie; Chen, Chunxu; Liu, Xiaoming; Li, Li

    2015-11-03

    Because roller element bearings (REBs) failures cause unexpected machinery breakdowns, their fault diagnosis has attracted considerable research attention. Established fault feature extraction methods focus on statistical characteristics of the vibration signal, which is an approach that loses sight of the continuous waveform features. Considering this weakness, this article proposes a novel feature extraction method for frequency bands, named Window Marginal Spectrum Clustering (WMSC) to select salient features from the marginal spectrum of vibration signals by Hilbert-Huang Transform (HHT). In WMSC, a sliding window is used to divide an entire HHT marginal spectrum (HMS) into window spectrums, following which Rand Index (RI) criterion of clustering method is used to evaluate each window. The windows returning higher RI values are selected to construct characteristic frequency bands (CFBs). Next, a hybrid REBs fault diagnosis is constructed, termed by its elements, HHT-WMSC-SVM (support vector machines). The effectiveness of HHT-WMSC-SVM is validated by running series of experiments on REBs defect datasets from the Bearing Data Center of Case Western Reserve University (CWRU). The said test results evidence three major advantages of the novel method. First, the fault classification accuracy of the HHT-WMSC-SVM model is higher than that of HHT-SVM and ST-SVM, which is a method that combines statistical characteristics with SVM. Second, with Gauss white noise added to the original REBs defect dataset, the HHT-WMSC-SVM model maintains high classification accuracy, while the classification accuracy of ST-SVM and HHT-SVM models are significantly reduced. Third, fault classification accuracy by HHT-WMSC-SVM can exceed 95% under a Pmin range of 500-800 and a m range of 50-300 for REBs defect dataset, adding Gauss white noise at Signal Noise Ratio (SNR) = 5. Experimental results indicate that the proposed WMSC method yields a high REBs fault classification accuracy and a

  15. Decadal variability of windstorms in the Gulf of Biscay: classification, trends and links with low frequency patterns

    NASA Astrophysics Data System (ADS)

    Rasilla Álvarez, Domingo; Garcia Codrón, Juan Carlos

    2010-05-01

    Although the northern coast of the Iberian Peninsula and western France are located southward of the preferred paths of the Atlantic extratropical disturbances, and consequently, the frequency of windstorms is lower than in northern Europe, they have been hit repeatedly in the last years by several windstorms, like Klaus storm, responsible for large economic damages and deaths of human beings, arising questions about the meaning of those events in the framework of the global warming. In this contribution we analyzed the occurrence of windstorms over the Gulf of Biscay area and link them to the atmospheric circulation at different spatial scales. Windstorms were identified on the basis of several criteria proposed in the literature, such as the occurrence of extreme wind speeds (98th percentile) at the σ0.995 level (REANALYSIS NCEP), local pressure indices (frequency of 24 hours pressure changes greater than 16 hPa or absolute pressure values lower than 980 hPa) and a gale index equal or larger than 35 units calculated following the rules of the automated Jenkinson and Collinson procedure. Those synthetic indices were compared with actual wind data obtained from synop messages from the coastal observatories of the area. Finally, since intense extratropical cyclones are often associated with severe windstorms, storm tracks and cyclone statistics were extracted from the CDC Map Room Climate Products Storm Track Data (http://www.cdc.noaa.gov/map/clim/st_data.html). The conjunction of those criteria is capable to identify most of the extreme wind events in the analyzed area with a high degree of accurancy, although some discrepancies appear, specially regarding the use of REANALYSIS wind data. Besides, the comparison with long term wind data revealed that most of the time series suffered problems of homogeneity, some of them really severe, due to changes in the environment of the stations or the meteorological devices. Furthermore, the use of such proxy indices of

  16. Transformation of Bacillus subtilis in chocolate milk: evidence for low frequency of establishment of cells transformed under non-selective conditions.

    PubMed

    Wittke, Anja; Lick, Sonja; Heller, Knut J

    2002-12-01

    Transformation of naturally competent Bacillus subtilis with plasmid was carried out in chocolate milk without antibiotics. Transformed cells were enumerated during the entire growth phase in chocolate milk. When DNA was added to aliquots of a batch culture after different times of incubation, transformation events were detected at all different growth stages. When DNA was added to a batch culture together with the inoculum, transformed cells were detected at the onset of exponential growth. However, apparently no or only limited growth of these transformed cells was observed. To clarify, whether the limitation of growth was due to suppression by non-transformed cells, different proportions of B. subtilis cells either carrying or not carrying the plasmid were mixed and inoculated into chocolate milk without antibiotic. Our results indicate that suppression appears to be of minor importance. Instead, plasmid-bearing cells appear to suffer from a prolonged lag-phase. However, the failure to exhibit significant growth of cells which had taken up the plasmid in chocolate milk appears to be due to failure of these cells to establish themselves as permanently transformed under non-selective conditions.

  17. Fourier transform and Vernier spectroscopy using an optical frequency comb at 3-54 μm

    NASA Astrophysics Data System (ADS)

    Khodabakhsh, Amir; Ramaiah-Badarla, Venkata; Rutkowski, Lucile; Johansson, Alexandra C.; Lee, Kevin F.; Jiang, Jie; Mohr, Christian; Fermann, Martin E.; Foltynowicz, Aleksandra

    2016-06-01

    We present a versatile mid-infrared frequency comb spectroscopy system based on a doubly resonant optical parametric oscillator tunable in the 3-5.4 {\\mu}m range and two detection methods, a Fourier transform spectrometer (FTS) and a Vernier spectrometer. Using the FTS with a multipass cell we measure high-precision broadband absorption spectra of CH$_4$ and NO at ~3.3 {\\mu}m and ~5.2 {\\mu}m, respectively, and of atmospheric species (CH$_4$, CO, CO$_2$ and H$_2$O) in air in the signal and idler wavelength range. The figure of merit of the system is on the order of 10$^{-8}$ cm$^{-1}$ Hz$^{-1/2}$ per spectral element, and multiline fitting yields minimum detectable concentrations of 10-20 ppb Hz$^{-1/2}$ for CH$_4$, NO and CO. For the first time in the mid-infrared, we perform continuous-filtering Vernier spectroscopy using a low finesse enhancement cavity, a grating and a single detector, and measure the absorption spectrum of CH$_4$ and H$_2$O in ambient air at ~3.3 {\\mu}m.

  18. Fourier transform and Vernier spectroscopy using an optical frequency comb at 3-5.4  μm.

    PubMed

    Khodabakhsh, Amir; Ramaiah-Badarla, Venkata; Rutkowski, Lucile; Johansson, Alexandra C; Lee, Kevin F; Jiang, Jie; Mohr, Christian; Fermann, Martin E; Foltynowicz, Aleksandra

    2016-06-01

    We present a versatile mid-infrared frequency comb spectroscopy system based on a doubly resonant optical parametric oscillator tunable in the 3-5.4 μm range and two detection methods: a Fourier transform spectrometer (FTS) and a continuous-filtering Vernier spectrometer (CF-VS). Using the FTS with a multipass cell, we measure high precision broadband absorption spectra of CH4 at 3.3 μm and NO at 5.25 μm, the latter for the first time with comb spectroscopy, and we detect atmospheric species (CH4, CO, CO2, and H2O) in air in the signal and idler ranges. Multiline fitting yields minimum detectable concentrations of 10-20  ppb Hz-1/2 for CH4, NO, and CO. For the first time in the mid-infrared, we perform CF-VS using an enhancement cavity, a grating, and a single detector, and we measure the absorption spectrum of CH4 and H2O in ambient air at ∼3.3  μm, reaching a 40 ppb concentration detection limit for CH4 in 2 ms.

  19. High-frequency variation and population drift in a newly transformed clone of BALB/3T3 cells

    SciTech Connect

    Rubin, H.; Arnstein, P.; Chu, B.M.

    1984-11-01

    During repeated passage of BALB/3T3 cells and testing for anchorage-independent growth, a single transformed clone was isolated from agar, and five subclones were derived from it. These subclones differed from one another in morphology on a solid substratum, efficiency and size of colony formation in agar, and rate of tumor formation in nude mice. With weekly passage over a period of 6 months, the differences in morphology and growth in agar gradually decreased. The subclone which produced the fastest-growing tumors after 18 weeks, and a change in the opposite direction was made by another subclone. There was no difference among the subclones in growth rate on plastic. The distribution of chromosome numbers was heterogeneous but overlapping in all the primary subclones at 16 and 24 weeks, with no statistically significant difference in the mean number of chromosomes per subclone. An extremely high degree of variation must have occurred to produce the multiple differences between the subclones, and the same type of variation could have been responsible for the subsequent changes with repeated passage. The high frequency and graded nature of the changes and the concurrent involvement of several traits suggest an epigenetic basis for the variation. 26 references, 8 figures, 1 table.

  20. Kinetics of electrons and neutral particles in radio-frequency transformer coupled plasma H- ion source at Seoul National University

    NASA Astrophysics Data System (ADS)

    Chung, K. J.; Dang, J. J.; Kim, J. Y.; Cho, W. H.; Hwang, Y. S.

    2016-10-01

    In volume production H- ion sources, control of electron temperature is essential due to its close correlation with the generation of vibrationally-excited hydrogen molecules in the driver region as well as the generation of H- ions by dissociative attachment in the extraction region. In the ion source group at Seoul National University (SNU) in Korea, a lot of research effort has been made to the development of a volume production H- ion source based on radio-frequency (RF) transformer-coupled plasma (TCP) for long lifetime continuous wave (CW) operation. It has a spiral RF antenna located outside the discharge chamber to generate a plasma with high electron temperature in the driver region and employs a magnetic filter field to prevent high energy electrons from being transported to the extraction region. In this paper, we present the recent progress on understanding of the underlying physics of the RF TCP H- ion source at SNU. Special attention is paid to the characterization of electron kinetics regime for controlling electron energy distribution and the influence of relaxation of neutral particles during the transport across the magnetic filter region. Effect of the degree of dissociation on the production of H- ions is also discussed.

  1. Process induced transformations during tablet manufacturing: phase transition analysis of caffeine using DSC and low frequency micro-Raman spectroscopy.

    PubMed

    Hubert, Sébastien; Briancon, Stéphanie; Hedoux, Alain; Guinet, Yannick; Paccou, Laurent; Fessi, Hatem; Puel, François

    2011-11-25

    The phase transition of a model API, caffeine Form I, was studied during tableting process monitored with an instrumented press. The formulation used had a plastic flow behavior according to the Heckel model in the compression pressure range of 70-170 MPa. The quantitative methods of analysis used were Differential Scanning Calorimetry (DSC) and low frequency Micro Raman Spectroscopy (MRS) which was used for the first time for the mapping of polymorphs in tablets. They brought complementary contributions since MRS is a microscopic spectral analysis with a spatial resolution of 5 μm(3) and DSC takes into account a macroscopic fraction (10mg) of the tablet. Phase transitions were present at the surfaces, borders and center of the tablets. Whatever the pressure applied during the compression process, the transition degree of caffeine Form I toward Form II was almost constant. MRS provided higher transition degrees (50-60%) than DSC (20-35%). MRS revealed that caffeine Form I particles were partially transformed in all parts of the tablets at a microscopic scale. Moreover, tablet surfaces showed local higher transition degree compared to the other parts.

  2. Slow-to-fast transformation of denervated soleus muscles by chronic high-frequency stimulation in the rat.

    PubMed Central

    Gorza, L; Gundersen, K; Lømo, T; Schiaffino, S; Westgaard, R H

    1988-01-01

    1. Adult soleus muscles were denervated and stimulated directly for 2-130 days with 'fast' (short pulse trains at 100 Hz) or 'slow' (continuously at 10 Hz, or long pulse trains at 15 Hz) stimulus patterns. 2. At the end of the period of stimulation isometric twitches and tetani and isotonic shortening velocities were measured. Frozen cross-sections were later examined with antibodies against myosin heavy chains specific for adult fast, adult slow and fetal myosin. 3. Isometric twitch duration (twitch time-to-peak and half-relaxation time) decreased during intermittent 100 Hz stimulation to values that were almost as fast as in the normal extensor digitorum longus (EDL) (95 and 94% transformation). The major part of the decrease occurred between 2 and 21 days after the onset of stimulation, and was accompanied by post-tetanic potentiation of the twitch, 'sag' in tension during an unfused tetanus, lower twitch/tetanus ratio and marked shifts to the right (higher frequencies) of the tension-frequency curve of the muscle. In contrast, during 10 or 15 Hz stimulation the isometric twitch duration remained slow, the twitch continued to show post-tetanic depression and absence of 'sag', while the twitch/tetanus ratio increased. 4. Denervation per se led to a slight increase and, then, after about a month, to a moderate and gradual decrease in twitch duration. The twitch/tetanus ratio increased markedly and post-tetanic depression became less pronounced or disappeared. Muscle weight and particularly tetanic tension were markedly reduced and these reductions were to a large extent counteracted by electrical stimulation. 5. Implantation of sham electrodes had no effect on twitch duration of denervated or innervated control muscles, but reduced tetanic tension in the innervated control muscles. 6. Maximum isotonic shortening velocity of the whole muscle (mm/s) increased during intermittent 100 Hz stimulation to a value as fast as in the normal EDL (110% transformation). Since

  3. Measurement of interstrand cross-link frequency and distance between interruptions in DNA exposed to 4,5',8-trimethylpsoralen and near-ultraviolet light

    SciTech Connect

    Matsuo, N.; Ross, P.M.

    1987-04-07

    Bifunctional psoralens react photochemically with DNA to form single-strand adducts and interstrand, chemical cross-links. Cross-link formation is first order with (P), the concentration of added psoralen, when (P) much less than Kd, the psoralen-DNA dissociation constant. DNA molecules containing interstrand cross-links are reversibly bihelical and so are readily detected. It was not heretofore possible to determine cross-link frequency in polydisperse DNA from the mass F of DNA spared cross-linkage. We have derived a statistical relation to calculate cross-link frequency at fixed light exposure and variable (P). We show here that S, the initial slope of the curve described by -ln F as a function of (P), is proportional to Mw, the weight-average molecular weight of nick-free DNA. The cross-link frequency at any (P) can be determined from k, a constant measured for DNA of known Mw at low cross-linkage. This relation is valid for DNA of any molecular weight distribution. In experiments with uniform length DNA, -ln F (cross-link frequency) increased in simple proportion to (P). Intact and restriction endonuclease HindIII digested phage lambda DNA molecules have discrete lengths. S for each was proportional to Mw of the twin helix even though the molecular weight distribution of the restriction fragments was skewed. S was proportional to Mw and to the median molecular weight of sheared cellular DNA over a wide range. Also, we found that 1/S was linear with exposure of cellular DNA to gamma radiation. S can therefore be used to calculate L, the average distance between interruptions in the double helix.

  4. a Phase-Coherent Link Between the Visible and Infrared Spectral Ranges Using a Combination of CW Opo and Femtosecond Laser Frequency Comb

    NASA Astrophysics Data System (ADS)

    Kovalchuk, E. V.; Peters, A.

    2009-04-01

    We report on the realization of a new technique for a phase-coherent link between the visible and infrared spectral ranges provided by a continuous-wave OPO in combination with a Ti:Sapphire femtosecond laser comb. We have developed a CH4-based infrared molecular clock by phase locking the repetition rate frequency of a Ti:Sapphire femtosecond laser comb to the optical frequency of a He-Ne/CH4 standard. We also performed a direct absolute frequency comparisons between an iodine stabilized laser at 532 nm and a methane stabilized laser at 3.39 μm.

  5. Chemical cross-linking of the urease complex from Helicobacter pylori and analysis by Fourier transform ion cyclotron resonance mass spectrometry and molecular modeling

    NASA Astrophysics Data System (ADS)

    Carlsohn, Elisabet; Ångström, Jonas; Emmett, Mark R.; Marshall, Alan G.; Nilsson, Carol L.

    2004-05-01

    Chemical cross-linking of proteins is a well-established method for structural mapping of small protein complexes. When combined with mass spectrometry, cross-linking can reveal protein topology and identify contact sites between the peptide surfaces. When applied to surface-exposed proteins from pathogenic organisms, the method can reveal structural details that are useful in vaccine design. In order to investigate the possibilities of applying cross-linking on larger protein complexes, we selected the urease enzyme from Helicobacter pylori as a model. This membrane-associated protein complex consists of two subunits: [alpha] (26.5 kDa) and [beta] (61.7 kDa). Three ([alpha][beta]) heterodimers form a trimeric ([alpha][beta])3 assembly which further associates into a unique dodecameric 1.1 MDa complex composed of four ([alpha][beta])3 units. Cross-linked peptides from trypsin-digested urease complex were analyzed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and molecular modeling. Two potential cross-linked peptides (present in the cross-linked sample but undetectable in [alpha], [beta], and native complex) were assigned. Molecular modeling of urease [alpha][beta] complex and trimeric urease units ([alpha][beta])3 revealed a linkage site between the [alpha]-subunit and the [beta]-subunit, and an internal cross-linkage in the [beta]-subunit.

  6. Mutation frequencies of X-linked mental retardation genes in families from the EuroMRX consortium.

    PubMed

    de Brouwer, Arjan P M; Yntema, Helger G; Kleefstra, Tjitske; Lugtenberg, Dorien; Oudakker, Astrid R; de Vries, Bert B A; van Bokhoven, Hans; Van Esch, Hilde; Frints, Suzanne G M; Froyen, Guy; Fryns, Jean-Pierre; Raynaud, Martine; Moizard, Marie-Pierre; Ronce, Nathalie; Bensalem, Anissa; Moraine, Claude; Poirier, Karine; Castelnau, Laetitia; Saillour, Yoann; Bienvenu, Thierry; Beldjord, Chérif; des Portes, Vincent; Chelly, Jamel; Turner, Gillian; Fullston, Tod; Gecz, Jozef; Kuss, Andreas W; Tzschach, Andreas; Jensen, Lars Riff; Lenzner, Steffen; Kalscheuer, Vera M; Ropers, Hans-Hilger; Hamel, Ben C J

    2007-02-01

    The EuroMRX family cohort consists of about 400 families with non-syndromic and 200 families with syndromic X-linked mental retardation (XLMR). After exclusion of Fragile X (Fra X) syndrome, probands from these families were tested for mutations in the coding sequence of 90 known and candidate XLMR genes. In total, 73 causative mutations were identified in 21 genes. For 42% of the families with obligate female carriers, the mental retardation phenotype could be explained by a mutation. There was no difference between families with (lod score >2) or without (lod score <2) significant linkage to the X chromosome. For families with two to five affected brothers (brother pair=BP families) only 17% of the MR could be explained. This is significantly lower (P=0.0067) than in families with obligate carrier females and indicates that the MR in about 40% (17/42) of the BP families is due to a single genetic defect on the X chromosome. The mutation frequency of XLMR genes in BP families is lower than can be expected on basis of the male to female ratio of patients with MR or observed recurrence risks. This might be explained by genetic risk factors on the X chromosome, resulting in a more complex etiology in a substantial portion of XLMR patients. The EuroMRX effort is the first attempt to unravel the molecular basis of cognitive dysfunction by large-scale approaches in a large patient cohort. Our results show that it is now possible to identify 42% of the genetic defects in non-syndromic and syndromic XLMR families with obligate female carriers. (c) 2006 Wiley-Liss, Inc.

  7. Repair of DNA-protein cross-links in an excision repair-deficient human cell line and its simian virus 40-transformed derivative

    SciTech Connect

    Gantt, R.; Taylor, W.G.; Camalier, R.F.; Stephens, E.V.

    1984-05-01

    DNA-protein cross-links are induced in mammalian cells by X-rays, ultraviolet light, fluorescent light, and numerous chemical carcinogens. Others have shown that these cross-links are repaired by normal cells but that excision repair-deficient xeroderma pigmentosum (XP) Group A cells, XP12BE, are deficient in repair of these bulky adducts. This paper compares the DNA-protein cross-link repair competency of another XP Group A strain, XP20S, with its more rapidly proliferating simian virus 40-transformed derivative line and with normal human skin fibroblasts. DNA-protein cross-links were induced with 20 microM transplatinum(II)diamminedichloride and assayed by the membrane alkaline elution procedure of Kohn. Treated and untreated cells are lysed on a polycarbonate membrane filter, and the coelution rates of the DNA at pH 12.2 are compared; DNA-protein cross-links retard elution of DNA. The repair competency of XP20S cells for trans-platinum(II)diamminedichloride-induced DNA-protein cross-links was similar to that of XP12BE cells, but the competency of the simian virus 40-transformed XP20S cells was nearly equal to that of normal human skin fibroblasts. These results suggest that either cell cycling compensates for the genetic deficiency present in the nucleotide excision process of XP Group A cells or that a process other than nucleotide excision can repair these lesions; this process requires cell cycling or activation by the virus.

  8. Optical Frequency Comb Fourier Transform Spectroscopy with Resolution Exceeding the Limit Set by the Optical Path Difference

    NASA Astrophysics Data System (ADS)

    Foltynowicz, Aleksandra; Rutkowski, Lucile; Johanssson, Alexandra C.; Khodabakhsh, Amir; Maslowski, Piotr; Kowzan, Grzegorz; Lee, Kevin; Fermann, Martin

    2015-06-01

    Fourier transform spectrometers (FTS) based on optical frequency combs (OFC) allow detection of broadband molecular spectra with high signal-to-noise ratios within acquisition times orders of magnitude shorter than traditional FTIRs based on thermal sources. Due to the pulsed nature of OFCs the interferogram consists of a series of bursts rather than a single burst at zero optical path difference (OPD). The comb mode structure can be resolved by acquiring multiple bursts, in both mechanical FTS systems and dual-comb spectroscopy. However, in all existing demonstrations the resolution was ultimately limited either by the maximum available OPD between the interferometer arms or by the total acquisition time enabled by the storage memory. We present a method that provides spectral resolution exceeding the limit set by the maximum OPD using an interferogram containing only a single burst. The method allows measurements of absorption lines narrower than the OPD-limited resolution without any influence of the instrumental lineshape function. We demonstrate this by measuring undistorted CO2 and CO absorption lines with linewidth narrower than the OPD-limited resolution using OFC-based mechanical FTS in the near- and mid-infrared wavelength ranges. The near-infrared system is based on an Er:fiber femtosecond laser locked to a high finesse cavity, while the mid-infrared system is based on a Tm:fiber-laser-pumped optical parametric oscillator coupled to a multi-pass cell. We show that the method allows acquisition of high-resolution molecular spectra with interferometer length orders of magnitude shorter than traditional FTIR. Mandon, J., G. Guelachvili, and N. Picque, Nat. Phot., 2009. 3(2): p. 99-102. Zeitouny, M., et al., Ann. Phys., 2013. 525(6): p. 437-442. Zolot, A.M., et al., Opt. Lett., 2012. 37(4): p. 638-640.

  9. Stressing of turbine-generator-exciter shafts by variable-frequency currents superimposed on DC currents in asynchronous HVDC links and following disturbances at converter stations

    SciTech Connect

    Hammons, T.J.; Bremner, J.J. )

    1994-09-01

    Ripple currents on the DC side of both HVDC synchronous and asynchronous. Links together with cleared HVDC and AC system disturbances can excite in some circumstances onerous torsional vibrations in large steam generator shafts. The problem has assumed importance in recent months on account of the HVDC Link between Scotland and Northern Ireland going ahead, on account of the proposed Eire/Wales Link, and because AC/DC/AC couplers are to be installed extensively to interconnect the East and West European Grid Systems. This paper discusses and analyses excitation of shaft torsional vibrations in steam turbine-generator-exciter shafts in close proximity to HVDC converter stations by (1) variable-frequency ripple currents superimposed on the DC currents in asynchronous Links, and (2) disturbances at bi-polar converter stations. The time response and tables show that for the systems studied variable-frequency ripple currents superimposed on the DC current in asynchronous Links can excite shaft torsional vibrations, the very small noncharacteristic currents could result in onerous shaft torques which might damage the machine, and that DC line faults at converter stations in close proximity of steam turbine-generator units can excite onerous turbine-generator shaft torsional response. Detailed simulation of the HVDC converter and generator is necessary for precise assessments of shaft torsional response following HVDC converter station faults. 500MW, 660MW, 1000MW and 1300MW machines are considered in the analyses that are made.

  10. Analysis of variable-frequency currents superimposed on DC currents in asynchronous HVDC Links in stressing turbine-generator-exciter shafts

    SciTech Connect

    Hammons, T.J.; Bremner, J.J.

    1995-03-01

    Ripple currents on the DC side of both HVDC asynchronous and synchronous Links can excite in some circumstances onerous torsional vibrations in large steam generator shafts. The problem has assumed importance in recent months on account of the HVDC Link between Scotland and Northern Ireland going ahead, on account of the proposed Eire/Wales Link, because AC/DC/AC couplers are to be installed to interconnect the East and West European Grid Systems, and because resonances have been observed on machines in close proximity to AC/DCIAC couplers and HVDC Links. This paper discusses and analyses excitation of shaft torsional vibrations in steam turbine-generator-exciter shafts in close proximity to HVDC converter stations by variable-frequency ripple currents superimposed on DC currents in asynchronous Links. It presents technical knowledge not arranged for convenient reference heretofore in studying possible excitation of turbine-generator-v/ exciter shaft torsional vibrations by non-characteristic HVDC converter harmonic currents if a machine should be considered to be at risk. Shaft torques in multi-machine networks are evaluated by proportioning HVDC Link disturbance currents to each machine at risk using system network data, generator data and fault analysis data considering frequency dependence of the system parameters. This scaling factor is calculated for different scenarios of system operation and load. Equivalent circuits for the synchronous generator are employed appropriately to correlate HVDC Link disturbance current impressed on the generator stator with s state torque excitation from which magnitude of turbine-generator-exciter shaft torque is deduced.

  11. Transformation of multiwall carbon nanotubes to onions with layers cross-linked by sp3 bonds under high pressure and shear deformation

    NASA Astrophysics Data System (ADS)

    Pankov, A. M.; Bredikhina, A. S.; Kulnitskiy, B. A.; Perezhogin, I. A.; Skryleva, E. A.; Parkhomenko, Yu. N.; Popov, M. Yu.; Blank, V. D.

    2017-08-01

    A pressure-induced phase transition of multiwall carbon nanotubes (MWNT) to a new structure at room temperature is studied using a shear diamond anvil cell, X-ray photoelectron spectra (XPS), transmission electron microscope (TEM) and Raman procedures. We observe a cardinal pressure-induced change in the nanoparticles shape from multi-shell tubes to multi-shell spheres. MWNT transforms to onions with layers cross-linked by sp3 bonds under the 45-65 GPa compressive stress combined with shear deformation at room temperature. TEM and XPS results show that about 40% of the carbon atoms in the new phase are sp3-bounded.

  12. Multi-frequency weak signal detection based on wavelet transform and parameter compensation band-pass multi-stable stochastic resonance

    NASA Astrophysics Data System (ADS)

    Han, Dongying; li, Pei; An, Shujun; Shi, Peiming

    2016-03-01

    In actual fault diagnosis, useful information is often submerged in heavy noise, and the feature information is difficult to extract. A novel weak signal detection method aimed at the problem of detecting multi-frequency signals buried under heavy background noise is proposed based on wavelet transform and parameter compensation band-pass multi-stable stochastic resonance (SR). First, the noisy signal is processed by parameter compensation, with the noise and system parameters expanded 10 times to counteract the effect of the damping term. The processed signal is decomposed into multiple signals of different scale frequencies by wavelet transform. Following this, we adjust the size of the scaled signals' amplitudes and reconstruct the signals; the weak signal frequency components are then enhanced by multi-stable stochastic resonance. The enhanced components of the signal are processed through a band-pass filter, leaving the enhanced sections of the signal. The processed signal is analyzed by FFT to achieve detection of the multi-frequency weak signals. The simulation and experimental results show that the proposed method can enhance the signal amplitude, can effectively detect multi-frequency weak signals buried under heavy noise and is valuable and usable for bearing fault signal analysis.

  13. Does the Discourse of Employer Linked Charter Schools Signal a Commitment to Work Force Development or Transformational Learning?

    ERIC Educational Resources Information Center

    Freeman, Eric; Lakes, Richard D.

    2005-01-01

    The latest model for educational reform emerging in the US vocational-technical delivery system is the employer linked charter school (ELCS). This emerging concept is viewed as a partnership between constituents in the regular school organization and employers who are directly involved in the school's design, governance, and delivery of learning…

  14. Linking ground-water age and chemistry data along flow paths: Implications for trends and transformations of nitrate and pesticides

    USGS Publications Warehouse

    Tesoriero, A.J.; Saad, D.A.; Burow, K.R.; Frick, E.A.; Puckett, L.J.; Barbash, J.E.

    2007-01-01

    Tracer-based ground-water ages, along with the concentrations of pesticides, nitrogen species, and other redox-active constituents, were used to evaluate the trends and transformations of agricultural chemicals along flow paths in diverse hydrogeologic settings. A range of conditions affecting the transformation of nitrate and pesticides (e.g., thickness of unsaturated zone, redox conditions) was examined at study sites in Georgia, North Carolina, Wisconsin, and California. Deethylatrazine (DEA), a transformation product of atrazine, was typically present at concentrations higher than those of atrazine at study sites with thick unsaturated zones but not at sites with thin unsaturated zones. Furthermore, the fraction of atrazine plus DEA that was present as DEA did not increase as a function of ground-water age. These findings suggest that atrazine degradation occurs primarily in the unsaturated zone with little or no degradation in the saturated zone. Similar observations were also made for metolachlor and alachlor. The fraction of the initial nitrate concentration found as excess N2 (N2 derived from denitrification) increased with ground-water age only at the North Carolina site, where oxic conditions were generally limited to the top 5??m of saturated thickness. Historical trends in fluxes to ground water were evaluated by relating the times of recharge of ground-water samples, estimated using chlorofluorocarbon concentrations, with concentrations of the parent compound at the time of recharge, estimated by summing the molar concentrations of the parent compound and its transformation products in the age-dated sample. Using this approach, nitrate concentrations were estimated to have increased markedly from 1960 to the present at all study sites. Trends in concentrations of atrazine, metolachlor, alachlor, and their degradates were related to the timing of introduction and use of these compounds. Degradates, and to a lesser extent parent compounds, were detected

  15. [Analyzing moiré pattern spectra based on the mutual transform between signals' waveform in time domain and their spectra in frequency space].

    PubMed

    Sun, Tao; Song, Yi-Zhong

    2013-11-01

    The mutual evolving processes of signals' waveforms and their spectra were numerically analyzed in time and frequency domains. The purpose was to research the essential relation between the signals' waveforms and their spectra. Then, the mutual transform principle was applied to analyze moiré pattern spectra, acquiring phase distribution information of the pattern. The rectangular window function was used to simulate the mutual transform between the impulse signal and direct-current waveform. Many rectangular window signals with deferent widths were obtained by changing the window width The unit impulse signal was obtained by changing the width down to zero, and the direct-current waveform obtained by changing the width up to +infinity. For smart, quick, and easy implementation of discrete Fourier transforms to rectangular pulses and obtain signals' spectra, a simple FFT system was worked out. With its calculating, the mutual evolving processes of signals' waveforms and their spectra were tracked deeply. All signals here were transformed with it. As the result, first, the spectra of rectangular window signals were in the form of sampling function [Sa(x) = sin(x)/x]. Second, with the change in the window's width, the waveform of Sa(x) changed. Third, when the width decreased, the waveform of Sa(x) extended, and vibrated more slowly. It changed into direct-current waveform when the width decreased to zero. Last, when the width increased, the waveform of Sa(x) shranked, and vibrated faster. It changed into impulse waveform when the width increased to +infinity. Signals' waveforms were in mutual transforms between the time and frequency domain. The transforming essence was considered as that the frequency component principle in Fourier series theory is reflected in the frequency domain. According to the principle of mutual transforms between signals' waveforms and their spectra, the first order spectrum of the moiré pattern was extracted out and normalized to a

  16. On the determination of the dynamic properties of a transformer oil based ferrofluid in the frequency range 0.1-20 GHz

    NASA Astrophysics Data System (ADS)

    Fannin, P. C.; Vekas, L.; Marin, C. N.; Malaescu, I.

    2017-02-01

    Complex susceptibility measurements provide a unique and efficient means for the investigation and determination of the dynamic properties of magnetic fluids. In particular, measurement of the frequency, f(Hz), and field, H(kA/m), dependent, complex susceptibility, χ(ω, Η)= χ‧(ω, Η)-iχ″(ω, Η), of magnetic fluids has proven to be a valuable and reliable technique for investigating such properties. The experimental data presented here was obtained from measurements of a transformer oil based ferrofluid, with measurements being performed over the frequency range 0.1-20 GHz and polarising fields 0-168 kA/m. In the case of transformer oil magnetic fluids, the normal measurement emphasis has been on the investigation of their dielectric properties, including the effects which lightning may have on these properties. Little has been reported on the measurement of the corresponding magnetic susceptibility, χ(ω), of such fluids and in this paper we address this fact. Thus we consider it worthwhile, in the case of a transformer with magnetic fluid transformer oil, being affected as a result of a lightening occurrence, to have knowledge of the fluids dynamic properties, at the microwave frequencies. In the process of determining the sample susceptibility profiles, it was found that the peak value of the χ″(ω) component, was approximately constant over the frequency range 2.4-6.3 GHz. From this it was determined that the fluid was effectively operating as a wideband absorber over a bandwidth of 3.9 GHz.

  17. Impact of turbulent phase noise on frequency transfer with asymmetric two-way ground-satellite coherent optical links

    NASA Astrophysics Data System (ADS)

    Robert, Clélia; Conan, Jean-Marc; Wolf, Peter

    2016-06-01

    Bidirectional ground-satellite laser links suffer from turbulence-induced scintillation and phase distortion. We study how turbulence impacts on coherent detection capacity and on the associated phase noise that restricts clock transfer precision. We evaluate the capacity to obtain a two-way cancellation of atmospheric effects despite the asymmetry between up and down link that limits the link reciprocity. For ground-satellite links, the asymmetry is induced by point-ahead angle and possibly the use, for the ground terminal, of different transceiver diameters, in reception and emission. The quantitative analysis is obtained thanks to refined end- to-end simulations under realistic turbulence and wind conditions as well as satellite cinematic. These temporally resolved simulations allow characterizing the coherent detection in terms of time series of heterodyne efficiency for different system parameters. We show that Tip/Tilt correction on ground is mandatory at reception for the down link and as a pre-compensation of the up link. Good correlation between up and down phase noise is obtained even with asymmetric apertures of the ground transceiver and in spite of pointing ahead angle. The reduction to less than 1 rad2 of the two-way differential phase noise is very promising for clock comparisons.

  18. Frequency scaling of slant-path atmospheric attenuation in the absence of rain for millimeter-wave links

    NASA Astrophysics Data System (ADS)

    Lucas-Vegas, María. José; Riera, José Manuel

    2016-11-01

    Broadband satellite communications systems, either used for broadcast or fixed satellite services, have grown continuously in recent years. This has led to the use of higher frequency bands, from the Ku (14/11 GHz) to the Ka band (30/20 GHz) in the last decade, and with the expectation of using the Q/V band (50/40 GHz) and even the W band (75-110 GHz) in the future. As frequency increases, radio wave propagation effects in the slant-path within the troposphere are becoming more and more relevant. The objective of this research is the proposal of frequency scaling approximations for the total attenuation in the absence of rain, a condition that occurs during the highest percentages of time, usually more than 95% in temperate climates. There is a strong relationship between total attenuation at different frequencies, as it arises from the same physical phenomena, namely, the presence of oxygen, water vapor, and clouds in the slant path. This strong relationship allows frequency scaling estimations to be proposed. In particular, polynomials for instantaneous frequency scaling of total attenuation under these conditions have been calculated for a set of frequencies in the range 10-100 GHz, based on atmospheric profiles of 60 sites from all over the world and physical models of attenuation. Global polynomials are provided for the 72 combinations of nine significant frequencies, which can be used to estimate attenuation at a frequency band from its known value at a different one. Refined expressions have also been calculated for different climatic zones, providing more precise estimations.

  19. Decoupling of mechanical systems based on in-situ frequency response functions: The link-preserving, decoupling method

    NASA Astrophysics Data System (ADS)

    Keersmaekers, Laurent; Mertens, Luc; Penne, Rudi; Guillaume, Patrick; Steenackers, Gunther

    2015-06-01

    Mechanical structures often consist of active and passive parts, the former containing the sources, the latter the transfer paths and the targets. The active and passive parts are connected to each other by means of links. In this paper, an innovative theoretical model has been developed to achieve the mathematical decoupling of such structures without disassembling the substructures, when the links connecting the structures are resilient enough. This procedure is required to identify components causing a specific Noise, Vibration and Harsh-ness (NVH) problem. The links are regarded as a parallel connection of springs and dampers, ignoring some physical properties. However, the new procedure will provide a powerful construction in which different link models can be investigated. Therefore, this procedure will be called the Link-Preserving, Decoupling Method (LPD method). The absence of a time-consuming physical decoupling procedure distinguishes the LPD method from all known methods such as the classical TPA method. The LPD method is validated by two numerical simulations using linear and nonlinear lumped parameter models and by an experimental case study.

  20. Changes in magnitude and frequency of heavy precipitation across China and its potential links to summer temperature

    NASA Astrophysics Data System (ADS)

    Gu, Xihui; Zhang, Qiang; Singh, Vijay P.; Shi, Peijun

    2017-04-01

    Changes in the magnitude, frequency and timing of heavy precipitation are closely related to the occurrence of floods and droughts, which hold a great deal of significance for management of agricultural irrigation and water resources. Records of daily precipitation and temperature from 728 stations across China were used to assess changes in the magnitude, frequency and timing of heavy precipitation using the Peak-over-Threshold (POT) with 95th percentile as the threshold. Because of the continuous nature of the magnitude and timing of heavy precipitation, the ;change point; method and the modified Mann-Kendall trend test method were used to detect change points (CPs) and slowly-varying changes, respectively. In addition, the segmented regression and Poisson regression methods were used to detect CPs and temporal trends in the frequency of heavy precipitation, respectively, with consideration of the count nature of the data. The results showed that 55% and 36% of the stations had CPs in mean and/or variance of the magnitude and timing, respectively, while the percentage is only 5.8% in the frequency. However, while there is limited evidence of significant trends in the magnitude and timing, strong evidence points to a significant increasing frequency in most regions of China. These changes may be partly explained by changes in summer temperature. Examination of the summer surface temperature records suggests that the areas, where the frequency of heavy precipitation has a significant increase, are also mostly characterized by significant increasing temperature. In addition, trends of the frequency vary between the periods before and after the turn point (TP) of summer temperature trends, especially in northern China where both the summer temperature and the frequency have shifted significantly decreasing trends to significantly increasing trends. A possible interpretation of these findings is that storms tend to be more frequent without significant changes in water

  1. More use almost always a means a smaller frequency effect: Aging, bilingualism, and the weaker links hypothesis

    PubMed Central

    Gollan, Tamar H.; Montoya, Rosa I.; Cera, Cynthia; Sandoval, Tiffany C.

    2008-01-01

    The “weaker links” hypothesis proposes that bilinguals are disadvantaged relative to monolinguals on speaking tasks because they divide frequency-of-use between two languages. To test this proposal we contrasted the effects of increased word use associated with monolingualism, language dominance, and increased age on picture naming times. In two experiments, younger and older bilinguals and monolinguals named pictures with high- or low-frequency names in English and (if bilingual) also in Spanish. In Experiment 1, slowing related to bilingualism and language dominance was greater for producing low- than high-frequency names. In Experiment 2, slowing related to aging was greater for producing low-frequency names in the dominant language, but when speaking the nondominant language, increased age attenuated frequency effects and age-related slowing was limited exclusively to high-frequency names. These results challenge competition based accounts of bilingual disadvantages in language production, and illustrate how between-group processing differences may emerge from cognitive mechanisms general to all speakers. PMID:19343088

  2. Solar Power Satellite (SPS) pilot beam and communication link subsystem investigation study, phase 1. [ionospheric propagation, radio frequency interference, and microwave transmission

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A preliminary engineering model of ionospheric interactions with the pilot beam was established and used to demonstrate that the dual frequency baseline pilot beam system might not be viable in the presence of an unstable transmission path. Alternate approaches to remove this difficulty are described. Although ionospheric fluctuations will not significantly degrade beam pointing or raise the sidelobe levels, they will reduce transmission efficiency by upwards of 25%. Mitigating strategies to substantially reduce this effect are proposed. Based on the Klystron noise spectrum, the pilot beam transmitter power was determined as a function of frequency offset from the power beam carrier frequency. The RFI from the pilot beam, on the ground and at geosynchronous orbit is shown. Noise levels on the earth's surface due to the SPS are presented as a function of frequency and the number of SPS systems. Analysis of the communication subsystem indicates that a standard telemetry line of 1.544 MB/s would satisfy both voice and data link requirements. Additional links would be required for TV and radio transmissions.

  3. Linking simulations and experiments for the multiscale tracking of thermally induced martensitic phase transformation in NiTi SMA

    NASA Astrophysics Data System (ADS)

    Gur, Sourav; Frantziskonis, George N.

    2016-10-01

    Martensitic phase transformation in NiTi shape memory alloys (SMA) occurs over a hierarchy of spatial scales, as evidenced from observed multiscale patterns of the martensitic phase fraction, which depend on the material microstructure and on the size of the SMA specimen. This paper presents a methodology for the multiscale tracking of the thermally induced martensitic phase transformation process in NiTi SMA. Fine scale stochastic phase field simulations are coupled to macroscale experimental measurements through the compound wavelet matrix method (CWM). A novel process for obtaining CWM fine scale wavelet coefficients is used that enhances the effectiveness of the method in transferring uncertainties from fine to coarse scales, and also ensures the preservation of spatial correlations in the phase fraction pattern. Size effects, well-documented in the literature, play an important role in designing the multiscale tracking methodology. Molecular dynamics (MD) simulations are employed to verify the phase field simulations in terms of different statistical measures and to demonstrate size effects at the nanometer scale. The effects of thermally induced martensite phase fraction uncertainties on the constitutive response of NiTi SMA is demonstrated.

  4. Evidence that several high-frequency human blood group antigens reside on phosphatidylinositol-linked erythrocyte membrane proteins.

    PubMed

    Telen, M J; Rosse, W F; Parker, C J; Moulds, M K; Moulds, J J

    1990-04-01

    Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired disorder associated with absence of expression of phosphatidylinositol (PI)-linked membrane proteins from circulating hematopoietic cells of multiple lineages. Recent work demonstrated that decay accelerating factor, one such PI-linked protein, bears the Cromer-related blood group antigens. This study demonstrated that other high incidence antigens, including Cartwright (Yta/Ytb), Holley-Gregory (Hy/Gya), John Milton Hagen (JMH), and Dombrock (Doa/Dob), are absent from the complement-sensitive (PNH III) erythrocytes of patients with PNH. The relatively normal, complement-insensitive erythrocytes from the same patients express these antigens normally. Therefore, these antigens most likely reside on PI-linked proteins absent from PNH III, but not PNH I, erythrocytes.

  5. Global gene expression profiling of brown to white adipose tissue transformation in sheep reveals novel transcriptional components linked to adipose remodeling.

    PubMed

    Basse, Astrid L; Dixen, Karen; Yadav, Rachita; Tygesen, Malin P; Qvortrup, Klaus; Kristiansen, Karsten; Quistorff, Bjørn; Gupta, Ramneek; Wang, Jun; Hansen, Jacob B

    2015-03-19

    Large mammals are capable of thermoregulation shortly after birth due to the presence of brown adipose tissue (BAT). The majority of BAT disappears after birth and is replaced by white adipose tissue (WAT). We analyzed the postnatal transformation of adipose in sheep with a time course study of the perirenal adipose depot. We observed changes in tissue morphology, gene expression and metabolism within the first two weeks of postnatal life consistent with the expected transition from BAT to WAT. The transformation was characterized by massively decreased mitochondrial abundance and down-regulation of gene expression related to mitochondrial function and oxidative phosphorylation. Global gene expression profiling demonstrated that the time points grouped into three phases: a brown adipose phase, a transition phase and a white adipose phase. Between the brown adipose and the transition phase 170 genes were differentially expressed, and 717 genes were differentially expressed between the transition and the white adipose phase. Thirty-eight genes were shared among the two sets of differentially expressed genes. We identified a number of regulated transcription factors, including NR1H3, MYC, KLF4, ESR1, RELA and BCL6, which were linked to the overall changes in gene expression during the adipose tissue remodeling. Finally, the perirenal adipose tissue expressed both brown and brite/beige adipocyte marker genes at birth, the expression of which changed substantially over time. Using global gene expression profiling of the postnatal BAT to WAT transformation in sheep, we provide novel insight into adipose tissue plasticity in a large mammal, including identification of novel transcriptional components linked to adipose tissue remodeling. Moreover, our data set provides a useful resource for further studies in adipose tissue plasticity.

  6. Direct estimation of the recombination frequency between the RB1 gene and two closely linked microsatellites using sperm typing.

    PubMed

    Girardet, A; Lien, S; Leeflang, E P; Beaufrère, L; Tuffery, S; Munier, F; Arnheim, N; Claustres, M; Pellestor, F

    1999-01-01

    In this study, single sperm typing has been used for high-resolution recombination analysis between the retinoblastoma gene and two closely linked extragenic microsatellites (D13S284 and D13S1307). The analysis of 1198 single sperm from three donors allowed the determination of recombination fractions between RB1.20 and D13S284 and RB1.20 and D13S1307 of 0.022 and 0.033, respectively. These results show that RB1 gene and the two microsatellites are closely linked, which validates their potential use in indirect genetic diagnosis of retinoblastoma.

  7. Adapted wavelet transform improves time-frequency representations: a study of auditory elicited P300-like event-related potentials in rats

    NASA Astrophysics Data System (ADS)

    Richard, Nelly; Laursen, Bettina; Grupe, Morten; Drewes, Asbjørn M.; Graversen, Carina; Sørensen, Helge B. D.; Bastlund, Jesper F.

    2017-04-01

    Objective. Active auditory oddball paradigms are simple tone discrimination tasks used to study the P300 deflection of event-related potentials (ERPs). These ERPs may be quantified by time-frequency analysis. As auditory stimuli cause early high frequency and late low frequency ERP oscillations, the continuous wavelet transform (CWT) is often chosen for decomposition due to its multi-resolution properties. However, as the conventional CWT traditionally applies only one mother wavelet to represent the entire spectrum, the time-frequency resolution is not optimal across all scales. To account for this, we developed and validated a novel method specifically refined to analyse P300-like ERPs in rats. Approach. An adapted CWT (aCWT) was implemented to preserve high time-frequency resolution across all scales by commissioning of multiple wavelets operating at different scales. First, decomposition of simulated ERPs was illustrated using the classical CWT and the aCWT. Next, the two methods were applied to EEG recordings obtained from prefrontal cortex in rats performing a two-tone auditory discrimination task. Main results. While only early ERP frequency changes between responses to target and non-target tones were detected by the CWT, both early and late changes were successfully described with strong accuracy by the aCWT in rat ERPs. Increased frontal gamma power and phase synchrony was observed particularly within theta and gamma frequency bands during deviant tones. Significance. The study suggests superior performance of the aCWT over the CWT in terms of detailed quantification of time-frequency properties of ERPs. Our methodological investigation indicates that accurate and complete assessment of time-frequency components of short-time neural signals is feasible with the novel analysis approach which may be advantageous for characterisation of several types of evoked potentials in particularly rodents.

  8. Studies on characteristics of resistive power calculated with discrete Fourier transform in a pulse-modulated radio frequency discharge.

    PubMed

    Huo, W G; Zhang, H; Ding, Z F

    2015-02-01

    In a pulse-modulated (PM) radio-frequency (RF) capacitively coupled plasma, the DFT (Discrete Fourier Transform)-calculated RF power and the corresponding phase shift between voltage and current measured with calibrated voltage and current probes present oscillations in the pulse rising and falling edges. The oscillating phase shift between voltage and current obtained in the falling edge is outside the expected value for a resistive-capacitive RF discharge. Numerical simulation and analytical analysis are made to interpret these abnormal characteristics and seek an approach to obtaining the reliable resistive (active) RF power. The oscillation is proved to be originated from the oscillating non-zero reactive RF power of the capacitor(s) in the load. At the time instant when the reactive RF power within an integer RF period is not zero, the reactive RF power is mistakenly regarded as the active RF power in the DFT analysis, as a result, the corresponding phase is thus incorrect and even outside the expected value for a resistive-capacitive load. The resistive RF power and the phase can be only correctly calculated at the time instant when the reactive RF power is zero. For a series (or parallel) RC (resistor-capacitor) load and a combined RC load with the dominated series (or parallel) RC impedance, the time instant of the zero reactive RF power is calculated with one of the two proposed empirical formulae. In practice, the DFT-calculated resistive RF power is obtained according to the following procedures: (1) applying DFT to the measured RF voltage and current signals to obtain the power and time instants for minimal phase shifts between voltage and current; (2) selecting the empirical formula to calculate time instants of the zero reactive RF power; (3) getting resistive powers at time instants of the zero reactive RF power. In real PM RF capacitively coupled plasmas, the empirical formula for the series RC load is selected to calculate the resistive RF power

  9. Transformation of metal-organic framework to polymer gel by cross-linking the organic ligands preorganized in metal-organic framework.

    PubMed

    Ishiwata, Takumi; Furukawa, Yuki; Sugikawa, Kouta; Kokado, Kenta; Sada, Kazuki

    2013-04-10

    Until now, seamless fusion of metal-organic frameworks (MOFs) and covalently cross-linked polymer gels (PG) at molecular level has been extremely rare, since these two matters have been regarded as opposite, that is, hard versus soft. In this report, we demonstrate transformation of cubic MOF crystals to PG via inner cross-linking of the organic linkers in the void space of MOF, followed by decomposition of the metal coordination. The obtained PG behaved as a polyelectrolyte gel, indicating the high content of ionic groups inside. Metal ions were well adsorbed in the PG due to its densely packed carboxylate groups. A chimera-type hybrid material consisting of MOF and PG was obtained by partial hydrolysis of resulting cross-linked MOF. The shape of resulting PG network well reflected the crystal structure of MOF employed as a template. Our results will connect the two different network materials that have been ever studied in the two different fields to provide new soft and hard hybrid materials, and the unique copolymerization in the large void space of the MOF will open a new horizon toward "ideal network polymers" never prepared before now.

  10. Inter-relationships Linking Probability of Becoming a Case of Nicotine Dependence With Frequency of Tobacco Cigarette Smoking.

    PubMed

    Vsevolozhskaya, Olga A; Anthony, James C

    2016-12-01

    Once smoking starts, some tobacco cigarette smokers (TCS) can make very rapid transitions into tobacco dependence syndromes (TCD). With adjustment for smoking frequency, we posit female excess risk for this rapid-onset TCD. In a novel application of functional analysis for tobacco research, we estimate four Hill function parameters and plot TCD risk against a gradient of smoking frequency, as observed quite soon after smoking onset. In aggregate, the National Surveys of Drug Use and Health, 2004-2013, identified 1546 newly incident TCS in cross-sectional research, each with standardized TCD assessment. Hill function estimates contradict our apparently over-simplistic hypothesis. Among newly incident TCS males with only 1-3 recent smoking days, an estimated 1%-3% had become rapid-onset TCD cases; non-overlapping confidence intervals show lower TCD risk for females. In contrast, among daily smokers, closer to 50% of female TCS showed rapid-onset TCD, versus under 20% of male TCS, but a larger sample will be needed to confirm the apparent female excess risk at the daily smoking frequency level. Smoking frequency and TCD onset become inter-dependent quite soon after TCS onset. Feedback loops are expected, and might explain a potential reversal of male-female differences across smoking frequency gradients. These novel epidemiological estimates prompt new thinking and questions about interventions. In this large sample epidemiological study, with a nationally representative sample of newly incident TCS assessed cross-sectionally, we see a quite rapid onset of tobacco dependence, with an early male excess that fades out at higher levels of smoking frequency. Next steps include development of outreach and intervention for this very rapid-onset tobacco dependence. © The Author 2016. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Rupture process of oceanic transform faults linked to material variability: local observations and models of the Gofar Fault, EPR

    NASA Astrophysics Data System (ADS)

    Roland, E. C.; McGuire, J. J.; Collins, J. A.; Lizarralde, D.; Liu, Y.; Behn, M. D.

    2011-12-01

    We present the first comprehensive study of the rupture process associated with the end of the earthquake cycle on a mid-ocean ridge transform fault (RTF) and consider it in the context of the detailed fault zone thermal and mechanical properties and seismic velocity structure. Seismicity that occurred during the 2008 rupture event on the western-most segment of the Gofar Fault on the East Pacific Rise included a Mw 6.0 mainshock earthquake, preceded by a prolific foreshock sequence, and followed months later by an earthquake swarm, each on discrete sections of the fault. These events were captured by a local array of ocean bottom seismometers and strong motion accelerometers, and for the first time, details of the spatial distribution of seismic slip provide insight into many outstanding questions that exist about RTF fault mechanics. While thermal rheologies work well at predicting the size of earthquakes on continents and along subduction zones, at oceanic transform faults low average seismic coupling estimates suggest that other factors must influence the mechanical behavior. We present the observed earthquake distribution along with a new, more realistic thermal model developed for the Gofar fault that improves upon the halfspace cooling model typically used to estimate the RTF thermal structure and thermally controlled seismogenic area. The 3D temperature structure is calculated using a visco-plastic rheology with non-Newtonian viscous mantle flow, shear heating, and hydrothermal circulation. Fault slip over multiple earthquake cycles is modeled in the rate and state friction framework using gabbro friction data and the new Gofar thermal model. We also present the seismic velocity structure, determined using arrival time tomography from a wide-angle refraction survey across the foreshock zone that illuminates a significant low velocity damage zone associated with the central Gofar Fault. Reduced seismic velocities at the base of the crust within the

  12. Sonication, Vacuum Infiltration and Thiol Compounds Enhance the Agrobacterium-Mediated Transformation Frequency of Withania somnifera (L.) Dunal

    PubMed Central

    Sivanandhan, Ganeshan; Kapil Dev, Gnajothi; Theboral, Jeevaraj; Selvaraj, Natesan; Ganapathi, Andy; Manickavasagam, Markandan

    2015-01-01

    In the present study, we have established a stable transformation protocol via Agrobacterium tumafacines for the pharmaceutically important Withania somnifera. Six day-old nodal explants were used for 3 day co-cultivation with Agrobacterium tumefaciens strain LBA4404 harbouring the vector pCAMIBA2301. Among the different injury treatments, sonication, vacuum infiltration and their combination treatments tested, a vacuum infiltration for 10 min followed by sonication for 10 sec with A. tumefaciens led to a higher transient GUS expression (84% explants expressing GUS at regenerating sites). In order to improve gene integration, thiol compounds were added to co-cultivation medium. A combined treatment of L-Cys at 100 mg/l, STS at 125 mg/l, DTT at 75 mg/l resulted in a higher GUS expression (90%) in the nodal explants. After 3 days of co-cultivation, the explants were subjected to three selection cycles with increasing concentrations of kanamycin [100 to 115 mg/l]. The integration and expression of gusA gene in T0 and T1 transgenic plants were confirmed by polymerase chain reaction (PCR), and Southern blott analysis. These transformed plants (T0 and T1) were fertile and morphologically normal. From the present investigation, we have achieved a higher transformation efficiency of (10%). Withanolides (withanolide A, withanolide B, withanone and withaferin A) contents of transformed plants (T0 and T1) were marginally higher than control plants. PMID:25927703

  13. Applying Frequency-Domain Equalization to Code-Division Multiple Access and Transform-Domain Communications Systems

    DTIC Science & Technology

    2008-03-01

    Captain, USAF AFIT/GE/ENG/08-33 DEPARTMENT OF THE AIR FORCE AIR UNIVERSITY AIR FORCE INSTITUTE OF TECHNOLOGY Wright-Patterson Air Force Base , Ohio...research examined the theory and application of using orthogonal fre- quency division multiplexing ( OFDM ), or discrete multi-tone (DMT), frequency...1 OFDM Orthogonal Frequency Division Multiplexing . . . . . . . . 4 QPSK Quadrature Phase Shift Keying . . . . . . . . . . . . . . . 4 QAM Quadrature

  14. An antibiotic linked to peptides and proteins is released by electron capture dissociation fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Fagerquist, Clifton K; Hudgins, Robert R; Emmett, Mark R; Håkansson, Kristina; Marshall, Alan G

    2003-04-01

    Desfuroylceftiofur (DFC) is a bioactive beta-lactam antibiotic metabolite that has a free thiol group. Previous experiments have shown release of DFC from plasma extracts after addition of a disulfide reducing agent, suggesting that DFC may be bound to plasma and tissue proteins through disulfide bonds. We have reacted DFC with [Arg(8)]-vasopressin (which has one disulfide bond) and bovine insulin (which has three disulfide bonds) and analyzed the reaction products by use of electron capture dissociation Fourier transform ion cyclotron resonance mass spectrometry (ECD FT-ICR MS), which has previously shown preferential cleavage of disulfide bonds. We observe cleavage of DFC from vasopressin and insulin during ECD, suggesting that DFC is indeed bound to peptides and proteins through disulfide bonds. Specifically, we observed dissociative loss of one, as well as two, DFC species during ECD of [vasopressin + 2(DFC-H) + 2H](2+) from a single electron capture event. Loss of two DFCs could arise from either consecutive or simultaneous loss, but in any case implies a gas phase disulfide exchange step. ECD of [insulin + DFC + 4H](4+) shows preferential dissociative loss of DFC. Combined with HPLC, ECD FT-ICR-MS may be an efficient screening method for detection of drug-biomolecule binding.

  15. Linking Organic Matter Deposition And Iron Mineral Transformations to Groundwater Arsenic Levels in the Mekong Delta, Cambodia

    SciTech Connect

    Quicksall, A.N.; Bostick, B.C.; Sampson, M.L.

    2009-05-21

    Enriched As in drinking water wells in south and Southeast Asia has increased the risk of cancer for nearly 100 million people. This enrichment is generally attributed to the reductive dissolution of Fe oxides; however, the complex expression of As enrichment in these areas is not yet well understood. Here, the coupled sedimentological and geochemical factors that contribute to the extent and spatial distribution of groundwater As concentrations in the Mekong River delta, Cambodia in an avulsed scroll bar sequence are examined. X-Ray absorption spectroscopy (XAS) was used to determine Fe and As speciation in redox preserved sediment collected from drilled cores. Dissolved As, Fe and S solution concentrations in existing and newly drilled wells (cores) differed considerably depending on their source sedimentology. The rapid burial of organic matter in the scroll bar sequence facilitated the development of extensive Fe-reducing conditions, and As release into the aquifer. In older features organic C levels are high enough to sustain extensive Fe reduction and provide ample SO{sub 4} which is reduced to sulfide. This S reduction impacts As levels; As is sequestered in sulfide minerals outside of the scrollbar sequence, decreasing pore water concentrations. In contrast, As is depleted in sediments from the scroll sequence, and associated with elevated pore water aqueous concentrations. The concentration and form of organic C in the scrollbar sequence is related to depositional environment, and can facilitate Fe and S mineral transformations, distinct sedimentary environments explain a portion of the inherent heterogeneity of aquifer As concentrations.

  16. Non-stationary signal analysis based on general parameterized time-frequency transform and its application in the feature extraction of a rotary machine

    NASA Astrophysics Data System (ADS)

    Zhou, Peng; Peng, Zhike; Chen, Shiqian; Yang, Yang; Zhang, Wenming

    2017-07-01

    With the development of large rotary machines for faster and more integrated performance, the condition monitoring and fault diagnosis for them are becoming more challenging. Since the time-frequency (TF) pattern of the vibration signal from the rotary machine often contains condition information and fault feature, the methods based on TF analysis have been widely-used to solve these two problems in the industrial community. This article introduces an effective non-stationary signal analysis method based on the general parameterized time-frequency transform (GPTFT). The GPTFT is achieved by inserting a rotation operator and a shift operator in the short-time Fourier transform. This method can produce a high-concentrated TF pattern with a general kernel. A multi-component instantaneous frequency (IF) extraction method is proposed based on it. The estimation for the IF of every component is accomplished by defining a spectrum concentration index (SCI). Moreover, such an IF estimation process is iteratively operated until all the components are extracted. The tests on three simulation examples and a real vibration signal demonstrate the effectiveness and superiority of our method.

  17. Agrobacterium tumefaciens-mediated creeping bentgrass (Agrostis stolonifera L.) transformation using phosphinothricin selection results in a high frequency of single-copy transgene integration.

    PubMed

    Luo, H; Hu, Q; Nelson, K; Longo, C; Kausch, A P; Chandlee, J M; Wipff, J K; Fricker, C R

    2004-04-01

    Genetic transformation of creeping bentgrass mediated by Agrobacterium tumefaciens has been achieved. Embryogenic callus initiated from seeds (cv. Penn-A-4) was infected with an A. tumefaciens strain (LBA4404) harboring a super-binary vector that contained an herbicide-resistant bar gene driven either by the CaMV 35S promoter or a rice ubiquitin promoter. Plants were regenerated from 219 independent transformation events. The overall stable transformation efficiency ranged from 18% to 45%. Southern blot and genetic analysis confirmed transgene integration in the creeping bentgrass genome and normal transmission and stable expression of the transgene in the T1 generation. All independent transformation events carried one to three copies of the transgene, and a majority (60-65%) contained only a single copy of the foreign gene with no apparent rearrangements. We report here the successful use of Agrobacterium for the large-scale production of transgenic creeping bentgrass plants with a high frequency of a single-copy transgene insertion that exhibit stable inheritance patterns.

  18. High frequency seismic noise generated from breaking swallow water ocean waves and the link to time-variable sea states

    NASA Astrophysics Data System (ADS)

    Poppeliers, C.; Mallinson, D. J.

    2015-12-01

    Breaking waves in the near-shore are known to generate a significant amount of high frequency (f>5 Hz) energy. We investigate the correlation between the spectrum of seismic energy and the local sea states. We deployed a single three-component broadband seismometer approximately 50 m from the sea shore and recorded continuously for approximately 10 days. Our observations show that during elevated sea states, and presumably larger breaking waves in the surf zone, the power spectral density of the wave-generated seismic energy shifts to lower frequencies and higher spectral amplitudes. The correlation of the seismic spectral power to the height and period of ocean waves suggests that seismic observations can be used as a proxy for local sea states, which may have implications for sea shore sediment transport.

  19. Ultra-Small, High-Frequency, and Substrate-Immune Microtube Inductors Transformed from 2D to 3D

    PubMed Central

    Yu, Xin; Huang, Wen; Li, Moyang; Comberiate, Thomas M.; Gong, Songbin; Schutt-Aine, Jose E.; Li, Xiuling

    2015-01-01

    Monolithic on-chip inductors are key passive devices in radio frequency integrated circuits (RFICs). Currently, 70–80% of the on-wafer area of most RFIC chips is occupied by the sprawling planar spiral inductors, and its operation frequency is limited to a few GHz. With continuous scaling of the transistor technology, miniaturization and high frequency operation of inductors have become the bottleneck to meet future demands of wireless communication systems. Here we report on-chip self-rolled-up 3D microtube inductors with extremely small footprint, unprecedented high frequency performance and weak dependence on substrate conductivity. The serpentine metal strips are deposited on an oppositely strained silicon nitrides (SiNx) bilayer. After releasing from the sacrificial layer underneath, the metal/SiNx layer is scrolled into a 3D hollow tubular structure by the strain induced unidirectional self-rolled-up technology. Compared to the planar spiral inductors with similar inductances and quality (Q) factors, the footprint of tube inductors is reduced by as much as two orders of magnitude, and the frequency at peak Q factor improves more than 5 times on doped substrates. The self-rolled-up 3D nanotechnology platform employed here, that “processes in 2D but functions in 3D”, is positioned to serve as a global solution for extreme RFIC miniaturization with improved performance. PMID:25913217

  20. Ultra-Small, High-Frequency, and Substrate-Immune Microtube Inductors Transformed from 2D to 3D

    NASA Astrophysics Data System (ADS)

    Yu, Xin; Huang, Wen; Li, Moyang; Comberiate, Thomas M.; Gong, Songbin; Schutt-Aine, Jose E.; Li, Xiuling

    2015-04-01

    Monolithic on-chip inductors are key passive devices in radio frequency integrated circuits (RFICs). Currently, 70-80% of the on-wafer area of most RFIC chips is occupied by the sprawling planar spiral inductors, and its operation frequency is limited to a few GHz. With continuous scaling of the transistor technology, miniaturization and high frequency operation of inductors have become the bottleneck to meet future demands of wireless communication systems. Here we report on-chip self-rolled-up 3D microtube inductors with extremely small footprint, unprecedented high frequency performance and weak dependence on substrate conductivity. The serpentine metal strips are deposited on an oppositely strained silicon nitrides (SiNx) bilayer. After releasing from the sacrificial layer underneath, the metal/SiNx layer is scrolled into a 3D hollow tubular structure by the strain induced unidirectional self-rolled-up technology. Compared to the planar spiral inductors with similar inductances and quality (Q) factors, the footprint of tube inductors is reduced by as much as two orders of magnitude, and the frequency at peak Q factor improves more than 5 times on doped substrates. The self-rolled-up 3D nanotechnology platform employed here, that ``processes in 2D but functions in 3D'', is positioned to serve as a global solution for extreme RFIC miniaturization with improved performance.

  1. Providing hydrogen maser timing stability to orbiting VLBI radio telescope observations by post-measurement compensation of linked frequency standard imperfections

    NASA Technical Reports Server (NTRS)

    Springett, James C.

    1994-01-01

    Orbiting VLBI (OVLBI) astronomical observations are based upon measurements acquired simultaneously from ground-based and earth-orbiting radio telescopes. By the mid-1990s, two orbiting VLBI observatories, Russia's Radioastron and Japan's VSOP, will augment the worldwide VLBI network, providing baselines to earth radio telescopes as large as 80,000 km. The challenge for OVLBI is to effectuate space to ground radio telescope data cross-correlation (the observation) to a level of integrity currently achieved between ground radio telescopes. VLBI radio telescopes require ultrastable frequency and timing references in order that long term observations may be made without serious cross-correlation loss due to frequency source drift and phase noise. For this reason, such instruments make use of hydrogen maser frequency standards. Unfortunately, space-qualified hydrogen maser oscillators are currently not available for use on OVLBI satellites. Thus, the necessary long-term stability needed by the orbiting radio telescope may only be obtained by microwave uplinking a ground-based hydrogen maser derived frequency to the satellite. Although the idea of uplinking the frequency standard intrinsically seems simple, there are many 'contaminations' which degrade both the long and short term stability of the transmitted reference. Factors which corrupt frequency and timing accuracy include additive radio and electronic circuit thermal noise, slow or systematic phase migration due to changes of electronic circuit temporal operating conditions (especially temperature), ionosphere and troposphere induced scintillations, residual Doppler-incited components, and microwave signal multipath propagation. What is important, though, is to realize that ultimate stability does not have to be achieved in real-time. Instead, information needed to produce a high degree of coherence in the subsequent cross-correlation operation may be derived from a two-way coherent radio link, recorded and later

  2. Linked Environment for Atmospheric Discovery (LEAD): Transforming the Sensing and Numerical Prediction of High Impact Local Weather Through Dynamic Adaptation

    NASA Astrophysics Data System (ADS)

    Ramamurthy, M.; Droegemeier, K.

    2006-12-01

    Those who have experienced the devastation of a tornado, the raging waters of a flash flood, or the paralyzing impacts of lake-effect snows understand that mesoscale weather develops rapidly, often with considerable uncertainty with regard to location. Such weather is also locally intense and frequently influenced by processes on both larger and smaller scales. Ironically, few of the technologies used to observe the atmosphere, predict its evolution, and compute, transmit, or store information about it operate in a manner that accommodates the dynamic behavior of mesoscale weather. Radars do not adaptively scan specific regions of thunderstorms; numerical models are run largely on fixed time schedules in fixed configurations; and cyberinfrastructure does not allow meteorological tools to run on-demand, change configurations in response to the weather, or provide the fault tolerance needed for rapid reconfiguration. As a result, today's weather technology is highly constrained and far from optimal when applied to any particular situation. This presentation describes a major paradigm shift now underway in the field of meteorology -- away from today's environment in which remote sensing systems, atmospheric prediction models, and hazardous weather detection systems operate in fixed configurations, and on fixed schedules largely independent of weather -- to one in which they can change their configuration dynamically in response to the evolving weather. A major driver of this change is a project known as Linked Environments for Atmospheric Discovery (LEAD) -- a 5-year NSF Large Information Technology Research (ITR) grant that is developing cyberinfrastructure to allow scientists, students, tools and sensors to interact with weather. This presentation will describe the research and technology development being performed to establish this capability

  3. Matrix Contraction by Dermal Fibroblasts Requires Transforming Growth Factor-β/Activin-Linked Kinase 5, Heparan Sulfate-Containing Proteoglycans, and MEK/ERK

    PubMed Central

    Chen, Yunliang; Shi-wen, Xu; van Beek, Jonathan; Kennedy, Laura; McLeod, Marilyn; Renzoni, Elisabetta A.; Bou-Gharios, George; Wilcox-Adelman, Sarah; Goetinck, Paul F.; Eastwood, Mark; Black, Carol M.; Abraham, David J.; Leask, Andrew

    2005-01-01

    Scarring is characterized by excessive synthesis and contraction of extracellular matrix. Here, we show that fibroblasts from scarred (lesional) areas of patients with the chronic fibrotic disorder diffuse scleroderma [diffuse systemic sclerosis (dSSc)] show an enhanced ability to adhere to and contract extracellular matrix, relative to fibroblasts from unscarred (nonlesional) areas of dSSc patients and dermal fibroblasts from normal, healthy individuals. The contractile abilities of normal and dSSc dermal fibroblasts were suppressed by blocking heparin sulfate-containing proteoglycan biosynthesis or antagonizing transforming growth factor-β receptor type I [activin-linked kinase (ALK5)] or ras/mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK). Compared with both normal and nonlesional fibroblasts, lesional dSSc fibroblasts overexpressed the heparin sulfate-containing proteoglycan syndecan 4. We also found that the procontractile signals from transforming growth factor (TGF)-β were integrated through syndecan 4 and MEK/ERK because the ability of TGFβ to induce contraction of dermal fibroblasts was prevented by MEK antagonism. TGFβ could not induce a contractile phenotype or phosphorylate ERK in syndecan 4−/− dermal fibroblasts. These results suggest that integrating TGFβ and ERK signals via syndecan 4 is essential for the contractile ability of dermal fibroblasts. We conclude that antagonizing MEK/ERK, TGFβ1/ALK5, or syndecan 4 may alleviate scarring in chronic fibrotic disease. PMID:16314481

  4. Linking photochemical transformation of an Antarctica Fulvic Acid to diminished bioavailability and oxidation of organic electron shuttles

    NASA Astrophysics Data System (ADS)

    Fimmen, R. L.; Guerard, J. J.; Miller, P. L.; Cory, R. M.; Chin, Y.; Foreman, C. M.; McKnight, D. M.

    2007-12-01

    Photolysis of fulvic acid isolated from Pony Lake, Antarctica, a hypereutrophic coastal pond located on Ross Island, was evaluated for transformation kinetics and photo-bleaching mechanisms by spectroscopy, as well as changes in bioavailability. The fulvic acid fraction of Pony Lake was isolated by sorption to non-ionic XAD-8 resin, and represents the fraction of the dissolved organic matter considered to be the most photo-reactive fraction. Spectroscopic and electrochemical analysis during Pony Lake fulvic acid photolysis reveals three fundamental alterations to the natural organic matter isolate: decreased molar absorptivity, decreased fluorescence, and a loss of reduced organic functional groups (potential electron shuttles). Surprisingly we observed no carbon loss to mineralization. Evaluation of the light absorbance decay kinetics in the presence/absence of oxygen indicate that approximately 70% of photo-bleaching occurs via direct pathways and 30% is due to reaction with photochemically generated reactive oxygen species (ROS). Of the ROS mediated pathways approximately 70% of the reactivity is attributable to hydroxyl-radical oxidation. Molecular level changes in fulvic acid showed a loss of electron-rich (reduced) components during photolysis, specifically redox active N/S functional groups. Reduced forms of organic nitrogen (amines) decrease in concentration, while sulfur moieties (thiols) are essentially eliminated during photolysis. Furthermore, as the suite of reduced fulvic acid components are photochemically oxidized, we observe a concomitant production of hydrogen peroxide, presumably due to the photo-reduction of dissolved oxygen coupled to organic matter oxidation. Decay kinetics of fluorescent components identified in the fulvic acid isolate were evaluated using parallel factor component analysis (PARAFAC) of excitation-emission matrices (EEMs), and further illustrate a loss of overall fluorescence and a decrease in the redox-active (electron

  5. Effects of fire at two frequencies on nitrogen transformations and soil chemistry in a nitrogen-enriched forest landscape

    Treesearch

    R. E. J. Boerner; J. A. Brinkman; E. K. Sutherland

    2004-01-01

    This study reports results of the application of dormant-season prescribed fire at two frequencies (periodic (two fires in 4 years) and annual) at four southern Ohio mixed-oak (Quercus spp.) forest sites to restore the ecosystem functional properties these sites had before the onset of fire suppression and chronic atmospheric deposition. Each forest...

  6. [Effect of Low-Intensity 900 MHz Frequency Electromagnetic Radiation on Rat Brain Enzyme Activities Linked to Energy Metabolism].

    PubMed

    Petrosyan, M S; Nersesova, L S; Gazaryants, M G; Meliksetyan, G O; Malakyan, M G; Bajinyan, S A; Akopian, J I

    2015-01-01

    The research deals with the effect of low-intensity 900 MHz frequency electromagnetic radiation (EMR), power density 25 μW/cm2, on the following rat brain and blood serum enzyme activities: creatine kinase (CK), playing a central role in the process of storing and distributing the cell energy, as well as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) that play a key role in providing the conjunction of carbohydrate and amino acid metabolism. The comparative analysis of the changes in the enzyme activity studied at different times following the two-hour single, as well as fractional, radiation equivalent of the total time showed that the most radiosensitive enzyme is the brain creatine kinase, which may then be recommended as a marker of the radio frequency radiation impact. According to the analysis of the changing dynamics of the CK, ALT and AST activity level, with time these changes acquire the adaptive character and are directed to compensate the damaged cell energy metabolism.

  7. Evaluation of selective control information detection scheme in orthogonal frequency division multiplexing-based radio-over-fiber and visible light communication links

    NASA Astrophysics Data System (ADS)

    Dalarmelina, Carlos A.; Adegbite, Saheed A.; Pereira, Esequiel da V.; Nunes, Reginaldo B.; Rocha, Helder R. O.; Segatto, Marcelo E. V.; Silva, Jair A. L.

    2017-05-01

    Block-level detection is required to decode what may be classified as selective control information (SCI) such as control format indicator in 4G-long-term evolution systems. Using optical orthogonal frequency division multiplexing over radio-over-fiber (RoF) links, we report the experimental evaluation of an SCI detection scheme based on a time-domain correlation (TDC) technique in comparison with the conventional maximum likelihood (ML) approach. When compared with the ML method, it is shown that the TDC method improves detection performance over both 20 and 40 km of standard single mode fiber (SSMF) links. We also report a performance analysis of the TDC scheme in noisy visible light communication channel models after propagation through 40 km of SSMF. Experimental and simulation results confirm that the TDC method is attractive for practical orthogonal frequency division multiplexing-based RoF and fiber-wireless systems. Unlike the ML method, another key benefit of the TDC is that it requires no channel estimation.

  8. Assessment of periodic sub-diurnal Earth rotation variations at tidal frequencies through transformation of VLBI normal equation systems

    NASA Astrophysics Data System (ADS)

    Artz, Thomas; Tesmer Née Böckmann, Sarah; Nothnagel, Axel

    2011-09-01

    We present an empirical model for periodic variations of diurnal and sub-diurnal Earth rotation parameters (ERPs) that was derived based on the transformation of normal equation (NEQ) systems of Very Long Baseline Interferometry (VLBI) observing sessions. NEQ systems that contain highly resolved polar motion and UT1-TAI with a temporal resolution of 15 min were generated and then transformed to the coefficients of the tidal ERP model to be solved for. To investigate the quality of this model, comparisons with empirical models from the Global Positioning System (GPS), another VLBI model and the model adopted by the conventions of the International Earth Rotation and Reference Systems Service (IERS) were performed. The absolute coefficients of these models agree almost completely within 7.5 μ as in polar motion and 0.5 μ s in UT1-TAI. Several bigger differences exist, which are discussed in this paper. To be able to compare the model estimates with results of the continuous VLBI campaigns, where signals with periods of 8 and 6 h were detected, terms in the ter- and quarter-diurnal band were included in the tidal ERP model. Unfortunately, almost no common features with the results of continuous VLBI campaigns or ERP predictions in these tidal bands can be seen.

  9. CF2 Detection in Radio-Frequency Ar/CHF3 Plasmas by Fourier Transform Infrared Spectroscopy

    NASA Technical Reports Server (NTRS)

    Kim, J. S.; Rao, M. V. V. S.; Cappelli, M. A.; Sharma, S. P.

    1999-01-01

    CFx radicals, in particular CF2, are instrumental in anisotropic etching of SiO2. In order to optimize the CFx radical population in a given process environment, it is imperative that we understand their production mechanism. Towards this goal, we have conducted a series of quantitative measurements of CF2 radicals in low pressure RF plasmas similar to those used in SiO2 etching. In this study, we present preliminary results for Ar/CHF3 plasmas operating at pressures ranging from 10-50 mTorr and powers ranging from 100-500 W in the GEC reference cell, modified for inductive (transformer) coupling. Fourier transform infrared (FTIR) spectroscop) is used to observe the absorption features of the CF2 radical in the 1114 cm-1 and 1096 cm-1 spectral regions. The FTIR spectrometer is equipped with a high-sensitivity mercury cadmium telluride (MCT) detector and has afixed resolution of 0.125 cm- 1. The CF2 concentrations are measured for a range of operating pressures and discharge power levels, and are compared to measurements of the relative CF2 concentrations made by mass spectrometry using the method of appearance potential for radical selectivity.

  10. CF2 Detection in Radio-Frequency Ar/CHF3 Plasmas by Fourier Transform Infrared Spectroscopy

    NASA Technical Reports Server (NTRS)

    Kim, J. S.; Rao, M. V. V. S.; Cappelli, M. A.; Sharma, S. P.

    1999-01-01

    CFx radicals, in particular CF2, are instrumental in anisotropic etching of SiO2. In order to optimize the CFx radical population in a given process environment, it is imperative that we understand their production mechanism. Towards this goal, we have conducted a series of quantitative measurements of CF2 radicals in low pressure RF plasmas similar to those used in SiO2 etching. In this study, we present preliminary results for Ar/CHF3 plasmas operating at pressures ranging from 10-50 mTorr and powers ranging from 100-500 W in the GEC reference cell, modified for inductive (transformer) coupling. Fourier transform infrared (FTIR) spectroscop) is used to observe the absorption features of the CF2 radical in the 1114 cm-1 and 1096 cm-1 spectral regions. The FTIR spectrometer is equipped with a high-sensitivity mercury cadmium telluride (MCT) detector and has afixed resolution of 0.125 cm- 1. The CF2 concentrations are measured for a range of operating pressures and discharge power levels, and are compared to measurements of the relative CF2 concentrations made by mass spectrometry using the method of appearance potential for radical selectivity.

  11. Ionospheric electron density irregularities observed by satellite-to-satellite, dual-frequency, low-low Doppler tracking link

    NASA Technical Reports Server (NTRS)

    Estes, R. D.; Grossi, M. D.

    1984-01-01

    A low-low, satellite-to-satellite, dual-frequency, Doppler tracking experiment was performed. The data are analyzed here for irregularities in electron density at the altitude of 212 km. The differential Doppler data with the relative motion term removed are integrated to obtain a representation of the electron density variation along the satellite path. Well-known large-scale features such as the equatorial geomagnetic anomaly and day/night ionization level differences are clearly observed in the integrated data. The larger crest of the morning geomagnetic anomaly is seen to occur in the southern (winter) hemisphere in agreement with previous observations. In addition, a sharp peak in the electron density at the day-to-night transition point is observed in two consecutive revolutions. This effect may be due to the previously postulated atmospheric shock wave generated by supersonic motion of the terminator.

  12. Motor dysfunction in the tottering mouse is linked to cerebellar spontaneous low frequency oscillations revealed by flavoprotein autofluorescence optical imaging

    NASA Astrophysics Data System (ADS)

    Chen, Gang; Popa, Laurentiu S.; Wang, Xinming; Gao, Wangcai; Barnes, Justin; Hendrix, Claudia M.; Hess, Ellen J.; Ebner, Timothy J.

    2009-02-01

    Flavoprotein autofluorescence optical imaging is developing into a powerful research tool to study neural activity, particularly in vivo. In this study we used this imaging technique to investigate the neuronal mechanism underlying the episodic movement disorder that is characteristic of the tottering (tg) mouse, a model of episodic ataxia type 2. Both EA2 and the tg mouse are caused by mutations in the gene encoding Cav2.1 (P/Q-type) voltage-gated Ca2+ channels. These mutations result in a reduction in P/Q Ca2+ channel function. Both EA2 patients and tg mice have a characteristic phenotype consisting of transient motor attacks triggered by stress, caffeine or ethanol. The neural events underlying these episodes of dystonia are unknown. Flavoprotein autofluorescence optical imaging revealed spontaneous, transient, low frequency oscillations in the cerebellar cortex of the tg mouse. Lasting from 30 - 120 minutes, the oscillations originate in one area then spread to surrounding regions over 30 - 60 minutes. The oscillations are reduced by removing extracellular Ca2+ and blocking Cav 1.2/1.3 (L-type) Ca2+ channels. The oscillations are not affected by blocking AMPA receptors or by electrical stimulation of the parallel fiber - Purkinje cell circuit, suggesting the oscillations are generated intrinsically in the cerebellar cortex. Conversely, L-type Ca2+ agonists generate oscillations with similar properties. In the awake tg mouse, transcranial flavoprotein imaging revealed low frequency oscillations that are accentuated during caffeine induced attacks of dystonia. The oscillations increase during the attacks of dystonia and are coupled to oscillations in face and hindlimb EMG activity. These transient oscillations and the associated cerebellar dysfunction provide a novel mechanism by which an ion channel disorder results in episodic motor dysfunction.

  13. High-frequency transformation of a methylotrophic yeast, Candida boidinii, with autonomously replicating plasmids which are also functional in Saccharomyces cerevisiae.

    PubMed

    Sakai, Y; Goh, T K; Tani, Y

    1993-06-01

    We have developed a transformation system which uses autonomous replicating plasmids for a methylotrophic yeast, Candida boidinii. Two autonomous replication sequences, CARS1 and CARS2, were newly cloned from the genome of C. boidinii. Plasmids having both a CARS fragment and the C. boidinii URA3 gene transformed C. boidinii ura3 cells to Ura+ phenotype at frequencies of up to 10(4) CFU/micrograms of DNA. From Southern blot analysis, CARS plasmids seemed to exist in polymeric forms as well as in monomeric forms in C. boidinii cells. The C. boidinii URA3 gene was overexpressed in C. boidinii on these CARS vectors. CARS1 and CARS2 were found to function as an autonomous replicating element in Saccharomyces cerevisiae as well. Different portions of the CARS1 sequence were needed for autonomous replicating activity in C. boidinii and S. cerevisiae. C. boidinii could also be transformed with vectors harboring a CARS fragment and the S. cerevisiae URA3 gene.

  14. Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A2, S/N 108, 08

    NASA Technical Reports Server (NTRS)

    Valdez, A.

    2000-01-01

    This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A2, S/N 108, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

  15. Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 108 2

    NASA Technical Reports Server (NTRS)

    Valdez, A.

    2000-01-01

    This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1 SIN 108, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

  16. Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 109

    NASA Technical Reports Server (NTRS)

    Valdez, A.

    2000-01-01

    This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 109, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

  17. Microwave-assisted Measurement of the Frequency Response of Terahertz HEB mixers with a Fourier Transform Spectrometer

    NASA Astrophysics Data System (ADS)

    Lobanov, Y. V.; Tong, Cheuk-Yu E.; Hedden, A. S.; Blundell, R.; Gol'tsman, G. N.

    2010-03-01

    We describe a novel method of operation of the HEB direct detector for use with a Fourier Transform Spectrometer. Instead of elevating the bath temperature, we have measured the RF response of waveguide HEB mixers by applying microwave radiation to select appropriate bias conditions. In our experiment, a microwave signal is injected in to the HEB mixer via its IF port. By choosing an appropriate injection level, the device can be operated close to the desired operating point. Furthermore, we have shown that both thermal biasing and microwave injection can reproduce the same spectral response of the HEB mixer. However, with the use of microwave injection, there is no need to wait for the mixer to reach thermal equilibrium, so characterisation can be done in less time. Also, the liquid helium consumption for our wet cryostat is also reduced. We have demonstrated that the signal-to-noise ratio of the FTS measurements can be improved with microwave injection.

  18. Pupil Dilation and EEG Alpha Frequency Band Power Reveal Load on Executive Functions for Link-Selection Processes during Text Reading

    PubMed Central

    Scharinger, Christian; Kammerer, Yvonne; Gerjets, Peter

    2015-01-01

    Executive working memory functions play a central role in reading comprehension. In the present research we were interested in additional load imposed on executive functions by link-selection processes during computer-based reading. For obtaining process measures, we used a methodology of concurrent electroencephalographic (EEG) and eye-tracking data recording that allowed us to compare epochs of pure text reading with epochs of hyperlink-like selection processes in an online reading situation. Furthermore, this methodology allowed us to directly compare the two physiological load-measures EEG alpha frequency band power and pupil dilation. We observed increased load on executive functions during hyperlink-like selection processes on both measures in terms of decreased alpha frequency band power and increased pupil dilation. Surprisingly however, the two measures did not correlate. Two additional experiments were conducted that excluded potential perceptual, motor, or structural confounds. In sum, EEG alpha frequency band power and pupil dilation both turned out to be sensitive measures for increased load during hyperlink-like selection processes in online text reading. PMID:26076026

  19. Pupil Dilation and EEG Alpha Frequency Band Power Reveal Load on Executive Functions for Link-Selection Processes during Text Reading.

    PubMed

    Scharinger, Christian; Kammerer, Yvonne; Gerjets, Peter

    2015-01-01

    Executive working memory functions play a central role in reading comprehension. In the present research we were interested in additional load imposed on executive functions by link-selection processes during computer-based reading. For obtaining process measures, we used a methodology of concurrent electroencephalographic (EEG) and eye-tracking data recording that allowed us to compare epochs of pure text reading with epochs of hyperlink-like selection processes in an online reading situation. Furthermore, this methodology allowed us to directly compare the two physiological load-measures EEG alpha frequency band power and pupil dilation. We observed increased load on executive functions during hyperlink-like selection processes on both measures in terms of decreased alpha frequency band power and increased pupil dilation. Surprisingly however, the two measures did not correlate. Two additional experiments were conducted that excluded potential perceptual, motor, or structural confounds. In sum, EEG alpha frequency band power and pupil dilation both turned out to be sensitive measures for increased load during hyperlink-like selection processes in online text reading.

  20. Linking High Frequency Variations in Stream Water DOC to Ages of Water Sources in Peat-Dominated Montane Watersheds

    NASA Astrophysics Data System (ADS)

    Tunaley, C.; Tetzlaff, D.; Lessels, J. S.; Soulsby, C.

    2015-12-01

    We combined time series of inferred DOC (from optical sensors) and stable isotopes in streams and watershed source areas to assess the link between water age and C fluxes. We monitored temporal dynamics of FDOM for 2 yrs at nested scales (0.9, 3.0 and 30km2) in a montane Scottish watershed. FDOM was strongly correlated (r2 ~ 0.8) with DOC allowing inference of 15 min timeseries. Marked seasonality was observed, with highest DOC concentrations (~25 mg l-1) in summer events and lower concentrations (~5mg l-1) in winter. During events, anticlockwise hysteresis was observed; consistent with expansion of the riparian saturation zone, increasing hydrological connectivity across peat soils and mobilizing DOC. Lag times for peak discharge and DOC were 1-12 hrs depending on event characteristics and antecedent conditions. Isotope time series from precipitation, streams and catchment source waters (overland flow and hillslope drainage) were also generated. These allowed us to model the non-stationary characteristics of their ages. Stream water age ranges from 3 months at high flows when overland flow dominates runoff to 4 yrs under baseflow. Overland flow age was a dominant influence on DOC transport. Highest concentrations occurred in small summer events with relatively young (<1 month old) overland flow waters generated after dry antecedent conditions, reflecting displacement of DOC-rich soil water. With wetting up in late summer/fall, overland flow is younger (< 1 week) diluting soil water DOC. Similar patterns occur across scales, though at 0.9km2 the dominance of a large peatland limits hysteresis, and maintains more constant DOC levels. At larger scales, DOC was more responsive but decreased more rapidly, reflecting a greater, but more transient influence of young overland flow. This shows the importance of riparian wetlands in regulating the quality and age of streams and the need to incorporate these sensitive areas in land management strategies.

  1. Frequency Band Analysis of Electrocardiogram (ECG) Signals for Human Emotional State Classification Using Discrete Wavelet Transform (DWT).

    PubMed

    Murugappan, Murugappan; Murugappan, Subbulakshmi; Zheng, Bong Siao

    2013-07-01

    [Purpose] Intelligent emotion assessment systems have been highly successful in a variety of applications, such as e-learning, psychology, and psycho-physiology. This study aimed to assess five different human emotions (happiness, disgust, fear, sadness, and neutral) using heart rate variability (HRV) signals derived from an electrocardiogram (ECG). [Subjects] Twenty healthy university students (10 males and 10 females) with a mean age of 23 years participated in this experiment. [Methods] All five emotions were induced by audio-visual stimuli (video clips). ECG signals were acquired using 3 electrodes and were preprocessed using a Butterworth 3rd order filter to remove noise and baseline wander. The Pan-Tompkins algorithm was used to derive the HRV signals from ECG. Discrete wavelet transform (DWT) was used to extract statistical features from the HRV signals using four wavelet functions: Daubechies6 (db6), Daubechies7 (db7), Symmlet8 (sym8), and Coiflet5 (coif5). The k-nearest neighbor (KNN) and linear discriminant analysis (LDA) were used to map the statistical features into corresponding emotions. [Results] KNN provided the maximum average emotion classification rate compared to LDA for five emotions (sadness - 50.28%; happiness - 79.03%; fear - 77.78%; disgust - 88.69%; and neutral - 78.34%). [Conclusion] The results of this study indicate that HRV may be a reliable indicator of changes in the emotional state of subjects and provides an approach to the development of a real-time emotion assessment system with a higher reliability than other systems.

  2. Frequency Band Analysis of Electrocardiogram (ECG) Signals for Human Emotional State Classification Using Discrete Wavelet Transform (DWT)

    PubMed Central

    Murugappan, Murugappan; Murugappan, Subbulakshmi; Zheng, Bong Siao

    2013-01-01

    [Purpose] Intelligent emotion assessment systems have been highly successful in a variety of applications, such as e-learning, psychology, and psycho-physiology. This study aimed to assess five different human emotions (happiness, disgust, fear, sadness, and neutral) using heart rate variability (HRV) signals derived from an electrocardiogram (ECG). [Subjects] Twenty healthy university students (10 males and 10 females) with a mean age of 23 years participated in this experiment. [Methods] All five emotions were induced by audio-visual stimuli (video clips). ECG signals were acquired using 3 electrodes and were preprocessed using a Butterworth 3rd order filter to remove noise and baseline wander. The Pan-Tompkins algorithm was used to derive the HRV signals from ECG. Discrete wavelet transform (DWT) was used to extract statistical features from the HRV signals using four wavelet functions: Daubechies6 (db6), Daubechies7 (db7), Symmlet8 (sym8), and Coiflet5 (coif5). The k-nearest neighbor (KNN) and linear discriminant analysis (LDA) were used to map the statistical features into corresponding emotions. [Results] KNN provided the maximum average emotion classification rate compared to LDA for five emotions (sadness − 50.28%; happiness − 79.03%; fear − 77.78%; disgust − 88.69%; and neutral − 78.34%). [Conclusion] The results of this study indicate that HRV may be a reliable indicator of changes in the emotional state of subjects and provides an approach to the development of a real-time emotion assessment system with a higher reliability than other systems. PMID:24259846

  3. Suppression of optical beat interference-noise in orthogonal frequency division multiple access-passive optical network link using self-homodyne balanced detection

    NASA Astrophysics Data System (ADS)

    Won, Yong-Yuk; Jung, Sang-Min; Han, Sang-Kook

    2014-08-01

    A new technique, which reduces optical beat interference (OBI) noise in orthogonal frequency division multiple access-passive optical network (OFDMA-PON) links, is proposed. A self-homodyne balanced detection, which uses a single laser for the optical line terminal (OLT) as well as for the optical network unit (ONU), reduces OBI noise and also improves the signal to noise ratio (SNR) of the discrete multi-tone (DMT) signal. The proposed scheme is verified by transmitting quadrature phase shift keying (QPSK)-modulated DMT signal over a 20-km single mode fiber. The optical signal to noise ratio (OSNR), that is required for BER of 10-5, is reduced by 2 dB in the balanced detection compared with a single channel due to the cancellation of OBI noise in conjunction with the local laser.

  4. Two-step sequential cross-linking of sugar beet pectin for transforming zein nanoparticle-based Pickering emulsions to emulgels.

    PubMed

    Soltani, Sahar; Madadlou, Ashkan

    2016-01-20

    Nanosized (<100 nm) zein spheres were employed for fabrication of a series of fish O/W Pickering emulsions. Although surface tension measurement informed the high potency of zein particles for interfacial adsorption, the prepared emulsions destabilized shortly. Electrostatic deposition of sugar beet pectin onto zein particles interfacial layer at pH 4.0 increased significantly the emulsion stability which was attributed to enhanced steric and electrostatic repulsions based on ζ-potential measurements. Pectin enrichment also increased the viscosity of the continuous phase of emulsion. Injection of the oxidative enzyme laccase into the pectin-enriched emulsion to cross-link the feruloyl-bearing pectin molecules and the subsequent addition of CaCl2 to set ion-mediated cross-linkages between carboxyl groups of pectin chains transformed Pickering emulsions to emulgels. The higher the pectin content, the shorter was the gelation time of emulsions. The obtained emulgels were self-standing and became harder along with increasing pectin content.

  5. The use of a novel signal analysis to identify the origin of idiopathic right ventricular outflow tract ventricular tachycardia during sinus rhythm: Simultaneous amplitude frequency electrogram transformation mapping

    PubMed Central

    Chung, Fa-Po; Lin, Chin-Yu; Lo, Men-Tzung; Liu, Che-An; Lin, Chen; Chang, Yi-Chung; Chang, Shih-Lin; Lo, Li-Wei; Hu, Yu-Feng; Tuan, Ta-Chuan; Chao, Tze-Fan; Liao, Jonan; Chang, Yao-Ting; Lin, Chung-Hsing; Hung, Yuan; Yamada, Shinya; Pan, Kuo-Li; Lin, Yenn-Jiang; Chen, Shih-Ann

    2017-01-01

    Introduction The signal characteristics of intracardiac bipolar electrograms at the origin of idiopathic RVOT-VT during sinus rhythm remain unclear. Objective The study sought to develop a novel real-time/online technique, simultaneous amplitude frequency electrogram transformation (SAFE-T), to quantify and localize the diseased ventricular substrate in idiopathic RVOT-VT. Methods We retrospectively investigated the intracardiac bipolar recordings in 70 consecutive patients (26% male, mean age 42±12 years) who underwent successful radiofrequency catheter ablation of idiopathic RVOT-VT. We quantified the extent of the frequency fraction of ventricular potentials during sinus rhythm or ventricular pacing using a novel formula, the product of instantaneous amplitude and frequency, and showed that in a 3D geometry as an online SAFE-T map. Results The characteristics of the HHT spectra of electrograms derived from VT origins demonstrated high frequency components (>70 Hz), which were independent of the rhythm. The density of the abnormal potentials at the VT origins were higher (VT origins, 7.5±2.3 sites/cm2 vs. surrounding myocardium, 1.5±1.3 sites/cm2, p<0.001), and were significantly decreased after ablation (0.7±0.6 sites/cm2, p<0.001). A small region of abnormal potentials were observed in the VT origins (mean area of 1.5±0.8 cm2). The SAFE-T maps predicted the VT origins with 92% sensitivity, 78% specificity with optimal cut-off value of >3.0 Hz·mV. Conclusion The online SAFE-T map was feasible for quantifying the diseased ventricular substrate, irrespective of the rhythm of activation, and can be used to identify the optimal ablation targets for idiopathic RVOT-VT. We found a limited region of abnormal potentials where the RVOT-VT origins were successfully ablated. PMID:28282453

  6. System and component design and test of a 10 hp, 18,000 rpm AC dynamometer utilizing a high frequency AC voltage link, part 1

    NASA Astrophysics Data System (ADS)

    Lipo, Thomas A.; Alan, Irfan

    1991-06-01

    Hard and soft switching test results conducted with one of the samples of first generation MOS-controlled thyristor (MCTs) and similar test results with several different samples of second generation MCT's are reported. A simple chopper circuit is used to investigate the basic switching characteristics of MCT under hard switching and various types of resonant circuits are used to determine soft switching characteristics of MCT under both zero voltage and zero current switching. Next, operation principles of a pulse density modulated converter (PDMC) for three phase (3F) to 3F two-step power conversion via parallel resonant high frequency (HF) AC link are reviewed. The details for the selection of power switches and other power components required for the construction of the power circuit for the second generation 3F to 3F converter system are discussed. The problems encountered in the first generation system are considered. Design and performance of the first generation 3F to 3F power converter system and field oriented induction moter drive based upon a 3 kVA, 20 kHz parallel resonant HF AC link are described. Low harmonic current at the input and output, unity power factor operation of input, and bidirectional flow capability of the system are shown via both computer and experimental results. The work completed on the construction and testing of the second generation converter and field oriented induction motor drive based upon specifications for a 10 hp squirrel cage dynamometer and a 20 kHz parallel resonant HF AC link is discussed. The induction machine is designed to deliver 10 hp or 7.46 kW when operated as an AC-dynamo with power fed back to the source through the converter. Results presented reveal that the proposed power level requires additional energy storage elements to overcome difficulties with a peak link voltage variation problem that limits reaching to the desired power level. The power level test of the second generation converter after the

  7. System and component design and test of a 10 hp, 18,000 rpm AC dynamometer utilizing a high frequency AC voltage link, part 1

    NASA Technical Reports Server (NTRS)

    Lipo, Thomas A.; Alan, Irfan

    1991-01-01

    Hard and soft switching test results conducted with one of the samples of first generation MOS-controlled thyristor (MCTs) and similar test results with several different samples of second generation MCT's are reported. A simple chopper circuit is used to investigate the basic switching characteristics of MCT under hard switching and various types of resonant circuits are used to determine soft switching characteristics of MCT under both zero voltage and zero current switching. Next, operation principles of a pulse density modulated converter (PDMC) for three phase (3F) to 3F two-step power conversion via parallel resonant high frequency (HF) AC link are reviewed. The details for the selection of power switches and other power components required for the construction of the power circuit for the second generation 3F to 3F converter system are discussed. The problems encountered in the first generation system are considered. Design and performance of the first generation 3F to 3F power converter system and field oriented induction moter drive based upon a 3 kVA, 20 kHz parallel resonant HF AC link are described. Low harmonic current at the input and output, unity power factor operation of input, and bidirectional flow capability of the system are shown via both computer and experimental results. The work completed on the construction and testing of the second generation converter and field oriented induction motor drive based upon specifications for a 10 hp squirrel cage dynamometer and a 20 kHz parallel resonant HF AC link is discussed. The induction machine is designed to deliver 10 hp or 7.46 kW when operated as an AC-dynamo with power fed back to the source through the converter. Results presented reveal that the proposed power level requires additional energy storage elements to overcome difficulties with a peak link voltage variation problem that limits reaching to the desired power level. The power level test of the second generation converter after the

  8. Detection and imaging of the moving target using frequency space-time adaptive processing and fractional Fourier transform

    NASA Astrophysics Data System (ADS)

    Wu, Jian; Jiang, Yongmei; Kuang, Gangyao

    2014-10-01

    As for multi-channel SAR, the spectrum of the clutter is spatially-temporally coupled, and the echo of the moving target is chirp signal. A novel method based on STAP and FrFT is proposed in this paper, which is used for moving target detection and parameter estimation. Two steps are used for fast target detection : the coarse detection in low range resolution and parameter estimation for the specific data where the moving target appears. This paper discusses the principle of frequency STAP for clutter suppression firstly, and subsequently infers that the signal after clutter suppression is chirp signal. Then FrFT is introduced to estimate the parameters of the output signal, which can be used to estimate the parameters of the moving target. Finally, the process of the proposed method is introduced. Matching function is constructed to compensate the phase deviation caused by movement and focus the moving target. The effectiveness of the proposed method is validated by the simulation.

  9. A stationary wavelet transform and a time-frequency based spike detection algorithm for extracellular recorded data

    NASA Astrophysics Data System (ADS)

    Lieb, Florian; Stark, Hans-Georg; Thielemann, Christiane

    2017-06-01

    Objective. Spike detection from extracellular recordings is a crucial preprocessing step when analyzing neuronal activity. The decision whether a specific part of the signal is a spike or not is important for any kind of other subsequent preprocessing steps, like spike sorting or burst detection in order to reduce the classification of erroneously identified spikes. Many spike detection algorithms have already been suggested, all working reasonably well whenever the signal-to-noise ratio is large enough. When the noise level is high, however, these algorithms have a poor performance. Approach. In this paper we present two new spike detection algorithms. The first is based on a stationary wavelet energy operator and the second is based on the time-frequency representation of spikes. Both algorithms are more reliable than all of the most commonly used methods. Main results. The performance of the algorithms is confirmed by using simulated data, resembling original data recorded from cortical neurons with multielectrode arrays. In order to demonstrate that the performance of the algorithms is not restricted to only one specific set of data, we also verify the performance using a simulated publicly available data set. We show that both proposed algorithms have the best performance under all tested methods, regardless of the signal-to-noise ratio in both data sets. Significance. This contribution will redound to the benefit of electrophysiological investigations of human cells. Especially the spatial and temporal analysis of neural network communications is improved by using the proposed spike detection algorithms.

  10. Absolute atomic oxygen and nitrogen densities in radio-frequency driven atmospheric pressure cold plasmas: Synchrotron vacuum ultra-violet high-resolution Fourier-transform absorption measurements

    SciTech Connect

    Niemi, K.; O'Connell, D.; Gans, T.; Oliveira, N. de; Joyeux, D.; Nahon, L.; Booth, J. P.

    2013-07-15

    Reactive atomic species play a key role in emerging cold atmospheric pressure plasma applications, in particular, in plasma medicine. Absolute densities of atomic oxygen and atomic nitrogen were measured in a radio-frequency driven non-equilibrium plasma operated at atmospheric pressure using vacuum ultra-violet (VUV) absorption spectroscopy. The experiment was conducted on the DESIRS synchrotron beamline using a unique VUV Fourier-transform spectrometer. Measurements were carried out in plasmas operated in helium with air-like N{sub 2}/O{sub 2} (4:1) admixtures. A maximum in the O-atom concentration of (9.1 {+-} 0.7) Multiplication-Sign 10{sup 20} m{sup -3} was found at admixtures of 0.35 vol. %, while the N-atom concentration exhibits a maximum of (5.7 {+-} 0.4) Multiplication-Sign 10{sup 19} m{sup -3} at 0.1 vol. %.

  11. Ancestral links of Chesapeake Bay region African Americans to specific Bight of Bonny (West Africa) microethnic groups and increased frequency of aggressive breast cancer in both regions.

    PubMed

    Jackson, Fatimah L C

    2008-01-01

    The high frequency of aggressive, early onset, and highly fatal breast cancer among Chesapeake Bay region African Americans suggests that there may be a contributing ancestral component. This study identifies the region's founding African, European, and Native American Indian populations using ethnogenetic layering and identifies the microethnic substructure of each founding continental aggregate. The largest component (38%) of the enslaved Africans brought to the Chesapeake Bay originally came from the coastal and hinterlands of the Bight of Bonny, a region with very high rates of aggressive, early onset breast cancer. Ethnogenetic layering is applied a second time to reveal the microethnic groups of the Bight of Bonny hinterlands with historical links to the Chesapeake Bay region. These analyses identify the specific microethnic groups within this region of Africa that may be the sources of relevant polymorphisms contributing to the etiology of aggressive breast cancer in the Chesapeake Bay. This report suggests a historical link between specific African microethnic groups and a US health disparity.

  12. Development of a New Class of Low Cost, High Frequency Link Direct DC to AC Converters for Solid Oxide Fuel Cells (SOFC)

    SciTech Connect

    Prasad Enjeti; J.W. Howze

    2003-12-01

    This project proposes to design and develop a new class of power converters (direct DC to AC) to drastically improve performance and optimize the cost, size, weight and volume of the DC to AC converter in SOFC systems. The proposed topologies employ a high frequency link; direct DC to AC conversion approach. The direct DC to AC conversion approach is more efficient and operates without an intermediate dc-link stage. The absence of the dc-link, results in the elimination of bulky, aluminum electrolytic capacitors, which in turn leads to a reduction in the cost, volume, size and weight of the power electronic converter. The feasibility of two direct DC to AC converter topologies and their suitability to meet SECA objectives will be investigated. Laboratory proto-type converters (3-5kW) will be designed and tested in Phase-1. A detailed design trade-off study along with the test results will be available in the form of a report for the evaluation of SECA Industrial partners. This project proposes to develop a new and innovative power converter technology suitable for Solid Oxide Fuel Cell (SOFC) power systems in accordance with SECA objectives. The proposed fuel cell inverter (FCI) employs state of the art power electronic devices configured in two unique topologies to achieve direct conversion of DC power (24-48V) available from a SOFC to AC power (120/240V, 60Hz) suitable for utility interface and powering stand alone loads. The primary objective is to realize cost effective fuel cell converter, which operates under a wide input voltage range, and output load swings with high efficiency and improved reliability.

  13. DOC and nitrate export linked to dominant rainfall-runoff processes, end-members and seasonality - a long-term high frequency measurement campaign

    NASA Astrophysics Data System (ADS)

    Schwab, M. P.; Klaus, J.; Pfister, L.; Weiler, M.

    2016-12-01

    Over the past decades, stream sampling protocols for hydro-geochemical parameters were often limited by logistical and technological constraints. While long-term monitoring protocols were typically based on weekly sampling intervals, high frequency sampling was commonly limited to a few single events. In this contribution, we combined high frequency and long-term measurements to understand DOC and nitrate dynamics in a forest headwater for different runoff events and seasons. Our study area is the forested Weierbach catchment (0.47 km2) in Luxembourg, where the fractured schist bedrock is covered by cambisol soils. The runoff response is characterized by a double peak behaviour. The first peak occurs during or right after a rainfall event triggered by fast near surface runoff generation processes, while a second delayed peak lasts several days and is generated by subsurface flow. This second peak occurs only if a distinct storage threshold of the catchment is exceeded. Our observations were carried out with a field deployable UV-Vis spectrometer measuring DOC and nitrate concentrations in-situ at 15 min intervals for more than two years. In addition, a long-term validation was carried out with data obtained from the analysis of water collected with grab samples. The long-term, high-frequency measurements allowed us to calculate a complete and detailed balance of DOC and nitrate export over two years. Transport behaviour of the DOC and nitrate showed different dynamics between the first and second hydrograph peaks. DOC is mainly exported during the first peaks, while nitrate is mostly exported during the delayed second peaks. Biweekly end-member measurement of soil and groundwater over several years enables us to link the behaviour of DOC and nitrate export to various end-members in the catchment. Altogether, the long-term and high-frequency time series provides the opportunity to study DOC and nitrate export processes without having to just rely only on either a

  14. Transforming the treatment for hemophilia B patients: update on the clinical development of recombinant fusion protein linking recombinant coagulation factor IX with recombinant albumin (rIX-FP).

    PubMed

    Santagostino, Elena

    2016-05-01

    Recombinant fusion protein linking recombinant coagulation factor IX with recombinant albumin (rIX-FP; Idelvion®(†)) is an innovative new treatment designed to extend the half-life of factor IX (FIX) and ease the burden of care for hemophilia B patients. The rIX-FP clinical development program - PROLONG-9FP - is in its advanced phases, with pivotal studies in previously treated adults, adolescents, and pediatrics now completed. Across all age groups studied, rIX-FP has demonstrated a markedly improved pharmacokinetic profile compared with plasma-derived and recombinant FIX treatments, with a 30-40% higher incremental recovery, an approximately 5-fold longer half-life, a lower clearance, and a greater area under the curve. rIX-FP has been very well tolerated with an excellent safety profile. In the pivotal studies, there have been no reports of FIX inhibitors or antidrug antibodies, and few treatment-related adverse events have been observed. Prophylactic regimens of rIX-FP administered once weekly to once every 14 days have been highly effective. When used for surgical prophylaxis, a single infusion of rIX-FP has been sufficient to maintain hemostasis, even during major orthopedic surgery. An ongoing study is now enrolling previously untreated patients and evaluating the possibility of extending the dosing interval to every 21 days. There is little doubt that rIX-FP will transform the treatment of hemophilia B. © 2016 Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  15. Multiresolution Low Frequency Geometric and Statistical Evolution of Euro-Atlantic Geopotential Height Linked with Monthly Precipitation over Paris, France from NOAA 20CR reanalysis ensemble 1901-2012

    NASA Astrophysics Data System (ADS)

    Fossa, Manuel; Massei, Nicolas; Dieppois, Bastien; Lecoq, Nicolas; Fournier, Matthieu; Laignel, Benoit

    2017-04-01

    local variables are studied at different interannual and decadal time scales using Discrete Wavelet transform methods to decompose the signal into quasi-independent time scales. - The geometric information is characterized without losing the global and local information by means of differential geometry and topological mappings resuming the information in low dimensional spaces. - The uncertainty (i.e internal variability) in the NOAA 20CR ensemble is assessed using Continuous Wavelet Transform methods like Coherence and Wavelet clustering to assess the dispersion within the reanalysis ensemble. This study tries to answer how geopotential height fields linked with discharge over the Paris Montsouris precipitation gauging station evolved from 1901 to 2012. It does so by taking into account the different low frequency time scales, characterizing the geometric and statistical evolution of the fields and discriminating natural variability from internal variability using the aforementioned methods.

  16. The Fethiye-Burdur Fault Zone: A component of upper plate extension of the subduction transform edge propagator fault linking Hellenic and Cyprus Arcs, Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Hall, J.; Aksu, A. E.; Elitez, I.; Yaltırak, C.; Çifçi, G.

    2014-11-01

    The Hellenic and Cyprus Arcs, that mark the convergent boundary of the African and Aegean-Anatolian plates, are offset along a subduction transform edge propagator ('STEP') fault running NE-SW along the Pliny and Strabo Trenches. The continuation of the fault to the northeast through the Rhodes Basin and into SW Anatolia is assessed. Seismic reflection profiles show that the structural architecture of the northern sector of the Rhodes Basin includes a large crustal-scale fold-thrust belt which is overprinted by numerous faults with small extensional stratigraphic separations. A protracted episode of convergence in the Miocene resulted in the development of a prominent NE-SW-striking and NW-verging fold-thrust belt in the Rhodes Basin. The absence of evaporites in the Rhodes Basin and several seaward prograded vertically stacked Quaternary delta successions resting at 2500-3500 m water depth collectively suggest that the Rhodes Basin must have remained above the depositional base of marine evaporite environment during the Messinian and that the region must have subsided very rapidly during the Pliocene-Quaternary. During the Pliocene-Quaternary, a NE-SW-trending belt developed across the Rhodes Basin: while the structural framework of this belt was characterised by reactivated thrusts in the central portion of the basin, a prominent zone of NE-SW-striking and NW- and SE-dipping faults with extensional separations developed in the northern portion of the basin. Two seismic profiles running parallel to the present-day coastline provide the much needed linkage between the Fethiye-Burdur Fault Zone onland and the reactivated thrusts in central Rhodes Basin, and show that the Pliocene-Quaternary zone of high-angle faults with extensional separations clearly link with the similarly trending and dipping strike-slip faults onland in the Eşen Valley, thus providing the continuity between the Pliny-Strabo Trenches in the southwest and the Fethiye-Burdur Fault Zone in the

  17. A fast method for the detection of vascular structure in images, based on the continuous wavelet transform with the Morlet wavelet having a low central frequency

    NASA Astrophysics Data System (ADS)

    Postnikov, Eugene B.; Tsoy, Maria O.; Kurochkin, Maxim A.; Postnov, Dmitry E.

    2017-04-01

    A manual measurement of blood vessels diameter is a conventional component of routine visual assessment of microcirculation, say, during optical capillaroscopy. However, many modern optical methods for blood flow measurements demand the reliable procedure for a fully automated detection of vessels and estimation of their diameter that is a challenging task. Specifically, if one measure the velocity of red blood cells by means of laser speckle imaging, then visual measurements become impossible, while the velocity-based estimation has their own limitations. One of promising approaches is based on fast switching of illumination type, but it drastically reduces the observation time, and hence, the achievable quality of images. In the present work we address this problem proposing an alternative method for the processing of noisy images of vascular structure, which extracts the mask denoting locations of vessels, based on the application of the continuous wavelet transform with the Morlet wavelet having small central frequencies. Such a method combines a reasonable accuracy with the possibility of fast direct implementation to images. Discussing the latter, we describe in details a new MATLAB program code realization for the CWT with the Morlet wavelet, which does not use loops completely replaced with element-by-element operations that drastically reduces the computation time.

  18. Transformation of human epidermal cells by transfection with plasmid containing simian virus 40 DNA linked to a neomycin gene is a defined medium

    SciTech Connect

    Su, R.T.; Yen-Chu Chang )

    1989-01-01

    A human epidermal cell culture was transformed by transfection with a recombinant plasmid containing simian virus 40 DNA with a deletion at the origin and an antibiotic (neomycin or G418) marker. A calcium phosphate-mediated DNA transfection method was optimized for introducing exogenous DNA into cells maintained in a fully defined medium. The transformed cells were propagated for more than 200 population doublings and did not appear to go through a crisis period. The growth characteristics of the transformed cells were similar to those found in normal epidermal cells. Transformed cells initially transfected with the recombinant plasmid could be propagated for more than 30 passages. Actively growing cells could then be repeatedly selected from cell populations based upon their neomycin (G418)-resistant phenotype for at least another 30 passages. Simian virus 40 T-antigen and extrachromosomal DNA containing plasmid- and SV40-specific DNA sequences were detected in the transformed cells. Because of their nononcogenic phenotype and defined growth requirements, the transformed cells provide a model for examining structural changes during cell proliferation and differentiation, and for exploring the multistage carcinogenesis of human epithelial cells.

  19. [A method of object detection for remote sensing-imagery based on spectral space transformation].

    PubMed

    Wu, Gui-Ping; Xiao, Peng-Feng; Feng, Xue-Zhi; Wang, Ke

    2013-03-01

    Object detection is an intermediate link for remote sensing image processing, which is an important guarantee of remote sensing application and services aspects. In view of the characteristics of remotely sensed imagery in frequency domain, a novel object detection algorithm based on spectral space transformation was proposed in the present paper. Firstly, the Fourier transformation method was applied to transform the image in spatial domain into frequency domain. Secondly, the wedge-shaped sample and overlay analysis methods for frequency energy were used to decompose signal into different frequency spectrum zones, and the center frequency values of object's features were acquired as detection marks in frequency domain. Finally, object information was detected with the matched Gabor filters which have direction and frequency selectivity. The results indicate that the proposed algorithm here performs better and it has good detection capability in specific direction as well.

  20. Genome-wide DNA methylation reprogramming in response to inorganic arsenic links inhibition of CTCF binding, DNMT expression and cellular transformation

    NASA Astrophysics Data System (ADS)

    Rea, Matthew; Eckstein, Meredith; Eleazer, Rebekah; Smith, Caroline; Fondufe-Mittendorf, Yvonne N.

    2017-02-01

    Chronic low dose inorganic arsenic (iAs) exposure leads to changes in gene expression and epithelial-to-mesenchymal transformation. During this transformation, cells adopt a fibroblast-like phenotype accompanied by profound gene expression changes. While many mechanisms have been implicated in this transformation, studies that focus on the role of epigenetic alterations in this process are just emerging. DNA methylation controls gene expression in physiologic and pathologic states. Several studies show alterations in DNA methylation patterns in iAs-mediated pathogenesis, but these studies focused on single genes. We present a comprehensive genome-wide DNA methylation analysis using methyl-sequencing to measure changes between normal and iAs-transformed cells. Additionally, these differential methylation changes correlated positively with changes in gene expression and alternative splicing. Interestingly, most of these differentially methylated genes function in cell adhesion and communication pathways. To gain insight into how genomic DNA methylation patterns are regulated during iAs-mediated carcinogenesis, we show that iAs probably targets CTCF binding at the promoter of DNA methyltransferases, regulating their expression. These findings reveal how CTCF binding regulates DNA methyltransferase to reprogram the methylome in response to an environmental toxin.

  1. Genome-wide DNA methylation reprogramming in response to inorganic arsenic links inhibition of CTCF binding, DNMT expression and cellular transformation

    PubMed Central

    Rea, Matthew; Eckstein, Meredith; Eleazer, Rebekah; Smith, Caroline; Fondufe-Mittendorf , Yvonne N.

    2017-01-01

    Chronic low dose inorganic arsenic (iAs) exposure leads to changes in gene expression and epithelial-to-mesenchymal transformation. During this transformation, cells adopt a fibroblast-like phenotype accompanied by profound gene expression changes. While many mechanisms have been implicated in this transformation, studies that focus on the role of epigenetic alterations in this process are just emerging. DNA methylation controls gene expression in physiologic and pathologic states. Several studies show alterations in DNA methylation patterns in iAs-mediated pathogenesis, but these studies focused on single genes. We present a comprehensive genome-wide DNA methylation analysis using methyl-sequencing to measure changes between normal and iAs-transformed cells. Additionally, these differential methylation changes correlated positively with changes in gene expression and alternative splicing. Interestingly, most of these differentially methylated genes function in cell adhesion and communication pathways. To gain insight into how genomic DNA methylation patterns are regulated during iAs-mediated carcinogenesis, we show that iAs probably targets CTCF binding at the promoter of DNA methyltransferases, regulating their expression. These findings reveal how CTCF binding regulates DNA methyltransferase to reprogram the methylome in response to an environmental toxin. PMID:28150704

  2. Determining insulation condition of 110kV instrument transformers. Linking PD measurement results from both gas chromatography and electrical method

    NASA Astrophysics Data System (ADS)

    Dan, C.; Morar, R.

    2017-05-01

    Working methods for on site testing of insulations: Gas chromatography (using the TFGA-P200 chromatographer); Electrical measurements of partial discharge levels using the digital detection, recording, analysis and partial discharge acquisition system, MPD600. First performed, between 2000-2015, were the chromatographic analyses concerning electrical insulating environments of: 102 current transformers, 110kV. Items in operation, functioning in 110/20kV substations. 38 voltage transformers, 110kV also in operation, functioning in 110/20kV substations. Then, electrical measurements of partial discharge inside instrument transformers, on site (power substations) were made (starting in the year 2009, over a 7-year period, collecting data until the year 2015) according to the provisions of standard EN 61869-1:2007 „Instrument transformers. General requirements”, applying, assimilated to it, type A partial discharge test procedure, using as test voltage the very rated 110kV distribution grid voltage. Given the results of two parallel measurements, containing: to this type of failure specific gas amount (H 2) and the quantitative partial discharge’ level, establishing a clear dependence between the quantity of partial discharges and the type and amount of in oil dissolved gases inside equipments affected by this type of defect: partial discharges, was expected. Of the „population” of instrument transformers subject of the two parallel measurements, the dependency between Q IEC (apparent charge) and (H 2) (hydrogen, gas amount dissolved within their insulating environment) represents a finite assemblage situated between the two limits developed on an empirical basis.

  3. The Use of Two-Station Ionosonde Data for IONCAP/ASAPS Model Validation on Transpolar Two-Hop, High-Frequency Skywave Radio Links

    DTIC Science & Technology

    1994-08-08

    5 ANALYSIS OF RESULTS ......... ................................................... 11 Dikson ...6 4 Six-Month Frequency Availability for Dikson and Resolute Bay ........................ 11 5 Twelve-Month Frequency Availability for Cape...probability bins. The IONOLNK2 computer program is described in appendix A. 9/10 Reverse Blank ANALYSIS OF RESULTS DIKSON (RUSSIA) AND RESOLUTE BAY (CANADA

  4. Transformational Learners: Transformational Teachers

    ERIC Educational Resources Information Center

    Jones, Marguerite

    2009-01-01

    Transformational learning, according to Mezirow (1981), involves transforming taken-for-granted frames of reference into more discriminating, flexible "habits of mind". In teacher education, transformative learning impacts on the development of students' action theories, self-efficacy and professional attributes. Although considered…

  5. The Transformations of Transformations.

    ERIC Educational Resources Information Center

    Lin, Francis Y.

    2000-01-01

    Harris's original idea of transformations has been changed several times in Chomsky's work. This article explicates these transformations, arguing that though their motivations are highly understandable, these transformations are not necessary for understanding the workings of natural languages. (Author/VWL)

  6. Unusual Transformation from a Solvent-Stabilized 1D Coordination Polymer to a Metal-Organic Framework (MOF)-Like Cross-Linked 3D Coordination Polymer.

    PubMed

    Lee, Seung-Chul; Choi, Eun-Young; Lee, Sang-Beom; Kim, Sang-Wook; Kwon, O-Pil

    2015-10-26

    An unusual 1D-to-3D transformation of a coordination polymer based on organic linkers containing highly polar push-pull π-conjugated side chains is reported. The coordination polymers are synthesized from zinc nitrate and an organic linker, namely, 2,5-bis{4-[1-(4-nitrophenyl)pyrrolidin-2-yl]butoxy}terephthalic acid, which possesses highly polar (4-nitrophenyl)pyrrolidine groups, with high dipole moments of about 7 D. The coordination polymers exhibit an unusual transformation from a soluble, solvent-stabilized 1D coordination polymer into an insoluble, metal-organic framework (MOF)-like 3D coordination polymer. The coordination polymer exhibits good film-forming ability, and the MOF-like films are insoluble in conventional organic solvents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Synthesis and characterization of combined cross-linked laccase and tyrosinase aggregates transforming acetaminophen as a model phenolic compound in wastewaters.

    PubMed

    Ba, Sidy; Haroune, Lounes; Cruz-Morató, Carles; Jacquet, Chloé; Touahar, Imad E; Bellenger, Jean-Phillipe; Legault, Claude Y; Jones, J Peter; Cabana, Hubert

    2014-07-15

    Laccase (EC 1.10.3.2) and tyrosinases (EC 1.14.18.1) are ubiquitous enzymes present in nature as they are known to originate from bacteria, fungi, plants, etc. Both laccase and tyrosinase are copper-containing phenoloxidases requiring readily available O2 without auxiliary cofactor for their catalytic transformation of numerous phenolic substrates. In the present study, laccase and tyrosinase have been insolubilized as combined crosslinked enzyme aggregates (combi-CLEA) using chitosan, a renewable and biodegradable polymer, as crosslinker. The combi-CLEA, with specific activity of 12.3 U/g for laccase and 167.4 U/g for tyrosinase, exhibited high enzymatic activity at pH5-8 and temperature at 5-30°C, significant resistance to denaturation and no diffusional restriction to its active site based upon the Michaelis-Menten kinetic parameters. Subsequently, the combi-CLEA was applied to the transformation of acetaminophen as a model phenolic compound in samples of real wastewaters in order to evaluate the potential efficiency of the biocatalyst. In batch mode the combi-CLEA transformed more than 80% to nearly 100% of acetaminophen from the municipal wastewater and more than 90% from the hospital wastewater. UPLC-MS analysis of acetaminophen metabolites showed the formation of its oligomers as dimers, trimers and tetramers due to the laccase and 3-hydroxyacetaminophen due to the tyrosinase. © 2013.

  8. Analysis of a modular generator for high-voltage, high-frequency pulsed applications, using low voltage semiconductors (< 1 kV) and series connected step-up (1:10) transformers.

    PubMed

    Redondo, L M; Fernando Silva, J; Margato, E

    2007-03-01

    This article discusses the operation of a modular generator topology, which has been developed for high-frequency (kHz), high-voltage (kV) pulsed applications. The proposed generator uses individual modules, each one consisting of a pulse circuit based on a modified forward converter, which takes advantage of the required low duty cycle to operate with a low voltage clamp reset circuit for the step-up transformer. This reduces the maximum voltage on the semiconductor devices of both primary and secondary transformer sides. The secondary winding of each step-up transformer is series connected, delivering a fraction of the total voltage. Each individual pulsed module is supplied via an isolation transformer. The assembled modular laboratorial prototype, with three 5 kV modules, 800 V semiconductor switches, and 1:10 step-up transformers, has 80% efficiency, and is capable of delivering, into resistive loads, -15 kV1 A pulses with 5 micros width, 10 kHz repetition rate, with less than 1 micros pulse rise time. Experimental results for resistive loads are presented and discussed.

  9. Consumption Frequency of Foods Away from Home Linked with Higher Body Mass Index and Lower Fruit and Vegetable Intake among Adults: A Cross-Sectional Study

    PubMed Central

    Seguin, Rebecca A.; Aggarwal, Anju; Vermeylen, Francoise; Drewnowski, Adam

    2016-01-01

    Introduction. Consumption of foods prepared away from home (FAFH) has grown steadily since the 1970s. We examined the relationship between FAFH and body mass index (BMI) and fruit and vegetable (FV) consumption. Methods. Frequency of FAFH, daily FV intake, height and weight, and sociodemographic data were collected using a telephone survey in 2008-2009. Participants included a representative sample of 2,001 adult men and women (mean age 54 ± 15 years) residing in King County, WA, with an analytical sample of 1,570. Frequency of FAFH was categorized as 0-1, 2–4, or 5+ times per week. BMI was calculated from self-reported height and weight. We examined the relationship between FAFH with FV consumption and BMI using multivariate models. Results. Higher frequency of FAFH was associated with higher BMI, after adjusting for age, income, education, race, smoking, marital status, and physical activity (women: p = 0.001; men: p = 0.003). There was a negative association between frequency of FAFH and FV consumption. FAFH frequency was significantly (p < 0.001) higher among males than females (43.1% versus 54.0% eating out 0-1 meal per week, resp.). Females reported eating significantly (p < 0.001) more FV than males. Conclusion. Among adults, higher frequency of FAFH was related to higher BMI and less FV consumption. PMID:26925111

  10. The small GTP-binding protein Rho links G protein-coupled receptors and Gα12 to the serum response element and to cellular transformation

    PubMed Central

    Fromm, Christian; Coso, Omar A.; Montaner, Silvia; Xu, Ningzhi; Gutkind, J. Silvio

    1997-01-01

    Receptors coupled to heterotrimeric G proteins can effectively stimulate growth promoting pathways in a large variety of cell types, and if persistently activated, these receptors can also behave as dominant-acting oncoproteins. Consistently, activating mutations for G proteins of the Gαs and Gαi2 families were found in human tumors; and members of the Gαq and Gα12 families are fully transforming when expressed in murine fibroblasts. In an effort aimed to elucidate the molecular events involved in proliferative signaling through heterotrimeric G proteins we have focused recently on gene expression regulation. Using NIH 3T3 fibroblasts expressing m1 muscarinic acetylcholine receptors as a model system, we have observed that activation of this transforming G protein-coupled receptors induces the rapid expression of a variety of early responsive genes, including the c-fos protooncogene. One of the c-fos promoter elements, the serum response element (SRE), plays a central regulatory role, and activation of SRE-dependent transcription has been found to be regulated by several proteins, including the serum response factor and the ternary complex factor. With the aid of reporter plasmids for gene expression, we observed here that stimulation of m1 muscarinic acetylcholine receptors potently induced SRE-driven reporter gene activity in NIH 3T3 cells. In these cells, only the Gα12 family of heterotrimeric G protein α subunits strongly induced the SRE, while Gβ1γ2 dimers activated SRE to a more limited extent. Furthermore, our study provides strong evidence that m1, Gα12 and the small GTP-binding protein RhoA are components of a novel signal transduction pathway that leads to the ternary complex factor-independent transcriptional activation of the SRE and to cellular transformation. PMID:9294169

  11. Dynamics of a combined Medea-underdominant population transformation system.

    PubMed

    Gokhale, Chaitanya S; Reeves, Richard Guy; Reed, Floyd A

    2014-05-07

    Transgenic constructs intended to be stably established at high frequencies in wild populations have been demonstrated to "drive" from low frequencies in experimental insect populations. Linking such population transformation constructs to genes which render them unable to transmit pathogens could eventually be used to stop the spread of vector-borne diseases like malaria and dengue. Generally, population transformation constructs with only a single transgenic drive mechanism have been envisioned. Using a theoretical modelling approach we describe the predicted properties of a construct combining autosomal Medea and underdominant population transformation systems. We show that when combined they can exhibit synergistic properties which in broad circumstances surpass those of the single systems. With combined systems, intentional population transformation and its reversal can be achieved readily. Combined constructs also enhance the capacity to geographically restrict transgenic constructs to targeted populations. It is anticipated that these properties are likely to be of particular value in attracting regulatory approval and public acceptance of this novel technology.

  12. A 400-mV 2.4-GHz frequency-shift keying transmitter using a capacitor switch across a transformer for a wide tuning range voltage-controlled oscillator

    NASA Astrophysics Data System (ADS)

    Miyahara, Yasunori; Ishikawa, Keisuke; Kuroda, Tadahiro

    2017-04-01

    We use a simple directly modulated closed loop to develop a 2.1-mW, 2.4-GHz frequency-shift keying (FSK) transmitter that operates on 400-mV DC supply. Connecting a capacitor bank switch via a transformer in the voltage control oscillator (VCO) to the frequency-divider circuit expands the frequency tuning range without reducing VCO performance. A prototype was fabricated using the 65-nm standard CMOS process with a chip size of 1.65 × 1.85 mm2. A modulation output signal spectrum of ‑42 dBc at 1.5 MHz with ‑6 dBm at the PA buffer output terminal; moreover, a VCO phase noise of ‑101 dBc/Hz at 1 MHz is achieved. The FSK transmitter can readily use voltages supplied by harvested energy because of the low power consumption of the sensor network.

  13. Comparison of particle-in-cell simulations with experimentally observed frequency shifts between ions of the same mass-to-charge in Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Leach, Franklin E; Kharchenko, Andriy; Heeren, Ron M A; Nikolaev, Eugene; Amster, I Jonathan

    2010-02-01

    It has been previously observed that the measured frequency of ions in a Fourier transform mass spectrometry experiment depend upon the number of trapped ions, even for populations consisting exclusively of a single mass-to-charge. Since ions of the same mass-to-charge are thought not to exert a space-charge effect among themselves, the experimental observation of such frequency shifts raises questions about their origin. To determine the source of such experimentally observed frequency shifts, multiparticle ion trajectory simulations have been conducted on monoisotopic populations of Cs(+) ranging from 10(2) ions to 10(6) ions. A close match to experimental behavior is observed. By probing the effect of ion number and orbital radius on the shift in the cyclotron frequency, it is shown that for a monoisotopic population of ions, the frequency shift is caused by the interaction of ions with their image-charge. The addition of ions of a second mass-to-charge to the simulation allows the comparison of the magnitude of the frequency shift resulting from space-charge (ion-ion) effects versus ion interactions with their image charge.

  14. The effect of radio frequency interference on the 136- to 138-MHz return link and 400.5- to 401.5-MHz forward link of the Tracking and Data Relay Satellite System

    NASA Technical Reports Server (NTRS)

    Jenny, J.; Lyttle, J. D.

    1973-01-01

    The purpose is to update the RFI estimates in the 136- to 138-MHz VHF band and to make estimates for the first time for the 400.5- to 401.5-MHz UHF band. These preliminary predictions are based on primarily ITU frequency-registration data, with missing data bridged by engineering judgement.

  15. Comparison of the frequency estimation of the DORIS/Jason2 oscillator thanks to the onboard DIODE and Time Transfer by Laser Link experiment

    NASA Astrophysics Data System (ADS)

    Jayles, C.; Exertier, P.; Martin, N.; Chauveau, J. P.; Samain, E.; Tourain, C.; Auriol, A.; Guillemot, P.

    2016-12-01

    The main applications for DORIS are precise orbit determination, and precise Geodesy. Onboard Jason-2 for instance, the DORIS tracking component is the French contribution to the precise orbit determination capability, a key capability for altimetry product scientific result accuracy. T2L2 is a time transfer technique based on the propagation of light pulses for synchronization between two clocks. Hosting T2L2 on-board Jason-2 was to allow for very fine DORIS USO (Ultra-Stable Oscillator) frequency monitoring, and for this purpose T2L2 was connected to the DORIS USO. Thanks to the continuous tracking of T2L2/Jason-2 by the Laser Ranging network it is possible to monitor the USO for several days, weeks, and even much longer, and thus to also compare with the DIODE (the DORIS on-board orbit determination software) frequency bias estimates. The DORIS USO frequency biases estimate comparison between two independent systems, T2L2 and DIODE, can be of benefit to both, allowing the accuracies of both systems to be better understood, and for improvements to be made to both systems. Such comparison is the central topic of the present paper. T2L2 monitors the DORIS on-board USO frequency with an accuracy of much better than 10-12 which is the specification for the Doppler instrumentation. The paper investigates the limits of the DORIS-DIODE frequency bias estimates using T2L2, showing that USO frequency compliance accuracy of 10-12 has been reached.

  16. Genetic transformation in Escherichia coli K12.

    PubMed

    Cosloy, S D; Oishi, M

    1973-01-01

    An auxotrophic strain of E. coli K12 treated with CaCl(2) was transformed for several markers at a frequency of up to 10(-6) per recipient cell by a DNA preparation isolated from a prototrophic strain. The transforming activity of the DNA preparation was eliminated by treatment with DNase, heat, or sonication, whereas RNase or Pronase treatment had little effect. Two closely linked genetic markers (leu and ara) showed a high degree of cotransformation linkage when high molecular weight DNA was used, but the linkage was almost completely eliminated when sheared, smaller molecular weight DNA was used. There is genetic evidence that the transformation is a result of the replacement of the preexisting genetic marker on the chromosome by that of the donor DNA.

  17. Reduced frequency of CD4(+)CD25(HIGH)FOXP3(+) cells and diminished FOXP3 expression in patients with Common Variable Immunodeficiency: a link to autoimmunity?

    PubMed

    Genre, J; Errante, P R; Kokron, C M; Toledo-Barros, M; Câmara, N O S; Rizzo, L V

    2009-08-01

    Common Variable Immunodeficiency (CVID) is a primary immunodeficiency disease characterized by defective immunoglobulin production and often associated with autoimmunity. We used flow cytometry to analyze CD4(+)CD25(HIGH)FOXP3(+) T regulatory (Treg) cells and ask whether perturbations in their frequency in peripheral blood could underlie the high incidence of autoimmune disorders in CVID patients. In this study, we report for the first time that CVID patients with autoimmune disease have a significantly reduced frequency of CD4(+)CD25(HIGH)FOXP3(+) cells in their peripheral blood accompanied by a decreased intensity of FOXP3 expression. Notably, although CVID patients in whom autoimmunity was not diagnosed had a reduced frequency of CD4(+)CD25(HIGH)FOXP3(+) cells, FOXP3 expression levels did not differ from those in healthy controls. In conclusion, these data suggest compromised homeostasis of CD4(+)CD25(HIGH)FOXP3(+) cells in a subset of CVID patients with autoimmunity, and may implicate Treg cells in pathological mechanisms of CVID.

  18. Transformation plasmonics

    NASA Astrophysics Data System (ADS)

    Kadic, Muamer; Guenneau, Sébastien; Enoch, Stefan; Huidobro, Paloma A.; Martín-Moreno, Luis; García-Vidal, Francisco J.; Renger, Jan; Quidant, Romain

    2012-07-01

    Surface plasmons polaritons (SPPs) at metal/dielectric interfaces have raised lots of expectations in the on-going quest towards scaling down optical devices. SPP optics offers a powerful and flexible platform for real two-dimensional integrated optics, capable of supporting both light and electrons. Yet, a full exploitation of the features of SPPs is conditioned by an accurate control of their flow. Most efforts have so far focused on the extrapolation of concepts borrowed from guided optics. This strategy has already led to many important breakthroughs but a fully deterministic control of SPP modes remains a challenge. Recently, the field of optics was stimulated by a novel paradigm, transformation optics, which offers the capability to control light flow in any desired fashion. While it has already significantly contributed to the design of metamaterials with unprecedented optical properties, its versatility offers new opportunities towards a fully deterministic control of SPPs and the design of a new class of plasmonic functionalities. Here, we review recent progress in the application of transformation optics to SPPs. We first briefly describe the theoretical formalism of transformation plasmonics, focusing on its specificities over its three-dimensional optical counterpart. Numerical simulations are then used to illustrate its capability to tame SPP flows at a metal interface patterned with a dielectric load. Finally, we review recent experimental implementations leading to unique SPP functionalities at optical frequencies.

  19. Frequencies of Six (Five Novel) STR Markers Linked to TUSC3 (MRT7) or NSUN2 (MRT5) Genes Used for Homozygosity Mapping of Recessive Intellectual Disability.

    PubMed

    Ghadami, Shirin; Mohammadi, Hossein Malek; Malbin, Jamileh; Masoodifard, Mahboobeh; Sarhaddi, Amene Bandehi; Tavakkoly-Bazzaz, Javad; Zeinali, Sirous

    2015-01-01

    Non-syndromic autosomal recessive intellectual disability (NS-ARID) is an extremely heterogeneous genetic disorder. Therefore, to investigate these genes, more research is required. One approach to investigate the NS-ARID loci is homozygosity mapping which requires appropriate STR markers within or flanking the gene/s of interest. In this research, we aimed to find novel STRs for two common NS-ARID genes (TUSC3 and NSUN2) and, in addition, to identify allele frequencies of those STR markers. The study group included 119 unrelated healthy individuals. STR markers were investigated using the UCSC genome browser web site and SERV software. Genotyping was determined by multiplex PCR. Data were evaluated using Gene Mapper software. Allele frequencies and observed heterozygosity rates were calculated using PowerStatV12. Deviation from Hardy-Weinberg equilibrium and expected heterozygosity were assessed using the DNAView software. In total, 56 alleles were detected. According to our research, D8TUSC3SU8.3 and D5NSUN2SU0.5 were the most informative STR markers in MRT7 and MRT5 loci, respectively and showed a high percentage of heterozygosity in Iranian population. The observed range of allele frequencies was from 3.4% to 32.4% and 0.8% to 18.9% for MRT5 and MRT7 loci, respectively. Further, we have evaluated other statistical surveys of these STR markers and discovered that all of the six listed STRs were informative and five meet the Hardy-Weinberg equilibrium for the tester group. Finding novel STRs, with high allele heterozygosity, is one of the most significant current finding in the present study for the two common NSARID genes. The recognized heterozygosity of these markers make MRT flanking STR markers very efficient to be used in diagnostic medical genetics labs or homozygosity mapping on NS-ARID.

  20. Male accessory gland infection frequency in infertile patients with chronic microbial prostatitis and irritable bowel syndrome: transrectal ultrasound examination helps to understand the links.

    PubMed

    Vicari, Enzo; Calogero, Aldo E; Condorelli, Rosita A; Vicari, Lucia O; La Vignera, Sandro

    2012-01-01

    The aim of this study was to evaluate the frequency of male accessory gland infection (MAGI) in patients with chronic bacterial prostatitis (CBP) plus irritable bowel syndrome (IBS) and to compare the sperm parameters of patients with or without MAGI. In addition, another objective of this study was to evaluate the ultrasound characterization of the anatomical space between the posterior wall of the prostate and the anterior wall of the rectum using transrectal ultrasonography. Fifty consecutive patients with the following criteria were enrolled: 1) infertility, 2) diagnosis of CBP, and 3) diagnosis of IBS according to the Rome III criteria. The following 2 age-matched control groups were also studied: infertile patients with CBP alone (n = 56) and fertile men (n = 30) who had fathered a child within the previous 3 months. Patients and controls underwent an accurate patient history; administration of the National Institutes of Health-Chronic Prostatitis Symptom Index and the Rome III questionnaires for prostatitis and IBS, respectively; physical examination; semen analysis; and transrectal ultrasound evaluation (limited to patients with CBP and IBS or CBP alone). A significantly higher frequency of MAGI was found in patients with CBP plus IBS (82.0%) compared with patients with CBP alone (53.6%) or fertile men (0%). The presence of MAGI in patients with CBP plus IBS was associated with a significantly lower sperm concentration, total number, and forward motility, and with a higher seminal leukocyte concentration compared with patients with CBP alone and MAGI. Sperm normal morphology was similar in the groups of patients. All sperm parameters did not differ significantly in both groups of patients without MAGI. With ultrasound evaluation, a significantly higher frequency of dilatation of prostatic venous plexus was found in patients with CBP plus IBS (75%) compared with patients with CBP alone (10%). Patients with CBP plus IBS had a significantly higher frequency of

  1. A Study of Photoreceivers for Free-Space, Analog, Intensity-Modulated, Direct-Detection Optical Links Operating at Microwave Frequencies

    DTIC Science & Technology

    2010-09-10

    The RF source (Agilent E8267C PSG Vector Signal Generator ( VSG )) provided two tones near 1 GHz and separated by 1.33 MHz to the MZM. The electrical...integrated TIA. 15 3.1 Source Calibration For the two-tone measurements performed in this investigation, the Agilent VSG was run with the...setting on the VSG . The results are shown graphically in Fig 9. The center frequency (1000.112 MHz) of the tones was chosen to be symmetrically

  2. High-frequency seismic noise generated from breaking shallow water ocean waves and the link to time-variable sea states

    NASA Astrophysics Data System (ADS)

    Poppeliers, Christian; Mallinson, David

    2015-10-01

    Breaking waves in the nearshore are known to generate a significant amount of high-frequency (f > 5 Hz) energy. We investigate the correlation between the spectrum of seismic energy and the local sea states. We deployed a single three-component broadband seismometer approximately 50 m from the seashore and recorded continuously for approximately 10 days. Our observations show that during elevated sea states, and presumably larger breaking waves in the surf zone, the power spectral density of the wave-generated seismic energy shifts to lower frequencies and higher spectral amplitudes. This is similar to the observation that large plunging breakers generate 1-20 Hz acoustic infrasound, suggesting that a significant portion of the infrasound couples into seismic energy at the water/sea floor interface. Based on our observations and previous models, it appears that the seismic spectrum is sensitive to the wave size but not sediment movement. Regardless, the correlation of the seismic spectral power to the height and period of ocean waves suggests that seismic observations can be used as a proxy for local sea states, which may have implications for seashore sediment transport.

  3. The dopamine-related polymorphisms BDNF, COMT, DRD2, DRD3, and DRD4 are not linked with changes in CSF dopamine levels and frequency of HIV infection.

    PubMed

    Horn, Anne; Scheller, C; du Plessis, S; Burger, R; Arendt, G; Joska, J; Sopper, S; Maschke, C M; Obermann, M; Husstedt, I W; Hain, J; Riederer, P; Koutsilieri, E

    2017-04-01

    We showed previously that higher levels in CSF dopamine in HIV patients are associated with the presence of the dopamine transporter (DAT) 10/10-repeat allele which was also detected more frequently in HIV-infected individuals compared to uninfected subjects. In the current study, we investigated further whether other genetic dopamine (DA)-related polymorphisms may be related with changes in CSF DA levels and frequency of HIV infection in HIV-infected subjects. Specifically, we studied genetic polymorphisms of brain-derived neurotrophic factor, catechol-O-methyltransferase, and dopamine receptors DRD2, DRD3, and DRD4 genetic polymorphisms in uninfected and HIV-infected people in two different ethnical groups, a German cohort (Caucasian, 72 individuals with HIV infection and 22 individuals without HIV infection) and a South African cohort (Xhosan, 54 individuals with HIV infection and 19 individuals without HIV infection). We correlated the polymorphisms with CSF DA levels, HIV dementia score, CD4(+) T cell counts, and HIV viral load. None of the investigated DA-related polymorphisms was associated with altered CSF DA levels, CD4(+) T cell count, viral load, and HIV dementia score. The respective allele frequencies were equally distributed between HIV-infected patients and controls. Our findings do not show any influence of the studied genetic polymorphisms on CSF DA levels and HIV infection. This is in contrast to what we found previously for the DAT 3'UTR VNTR and highlights the specific role of the DAT VNTR in HIV infection and disease.

  4. miRNAs as common regulators of the transforming growth factor (TGF)-β pathway in the preeclamptic placenta and cadmium-treated trophoblasts: Links between the environment, the epigenome and preeclampsia.

    PubMed

    Brooks, Samira A; Martin, Elizabeth; Smeester, Lisa; Grace, Matthew R; Boggess, Kim; Fry, Rebecca C

    2016-12-01

    Preeclampsia (PE) is a pregnancy disorder characterized by high blood pressure and proteinuria that can cause adverse health effects in both mother and fetus. There is no current cure for PE other than delivery of the fetus/placenta. While the etiology is unknown, poor placentation due to aberrant signaling of growth and angiogenic factors has been postulated as a causal factor of PE. In addition, environmental contaminants, such as the metal cadmium (Cd), have been linked to placental toxicity and increased risk of developing PE. Here, we use a translational study design to investigate genomic and epigenomic alterations in both placentas and placental trophoblasts, focused on the angiogenesis-associated transforming growth factor-beta (TGF-β) pathway. Genes within the TGF-β pathway displayed increased expression in both the preeclamptic placenta and Cd-treated trophoblasts. In addition, miRNAs that target the TGF-β pathway were also significantly altered within the preeclamptic placenta and Cd-treated trophoblasts. Integrative analysis resulted in the identification of a subset of Cd-responsive miRNAs, including miR-26a and miR-155, common to preeclamptic placentas and Cd-treated trophoblasts. These miRNAs have previously been linked to PE and are predicted to regulate members of the TGF-β pathway. Results from this study provide future targets for PE treatment. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  5. Observations of wave transformation over a fringing coral reef and the importance of low-frequency waves and offshore water levels to runup, overwash, and coastal flooding

    USGS Publications Warehouse

    Cheriton, Olivia; Storlazzi, Curt; Rosenberger, Kurt

    2016-01-01

    Many low-lying tropical islands are susceptible to sea level rise and often subjected to overwash and flooding during large wave events. To quantify wave dynamics and wave-driven water levels on fringing coral reefs, a 5 month deployment of wave gauges and a current meter was conducted across two shore-normal transects on Roi-Namur Island in the Republic of the Marshall Islands. These observations captured two large wave events that had waves with maximum heights greater than 6 m with peak periods of 16 s over the fore reef. The larger event coincided with a peak spring tide, leading to energetic, highly skewed infragravity (0.04–0.004 Hz) and very low frequency (0.004–0.001 Hz) waves at the shoreline, which reached heights of 1.0 and 0.7 m, respectively. Water surface elevations, combined with wave runup, reached 3.7 m above the reef bed at the innermost reef flat adjacent to the toe of the beach, resulting in flooding of inland areas. This overwash occurred during a 3 h time window that coincided with high tide and maximum low-frequency reef flat wave heights. The relatively low-relief characteristics of this narrow reef flat may further drive shoreline amplification of low-frequency waves due to resonance modes. These results (1) demonstrate how the coupling of high offshore water levels with low-frequency reef flat wave energetics can lead to large impacts along fringing reef-lined shorelines, such as island overwash, and (2) lend support to the hypothesis that predicted higher sea levels will lead to more frequent occurrences of these extreme events, negatively impacting coastal resources and infrastructure.

  6. Observations of wave transformation over a fringing coral reef and the importance of low-frequency waves and offshore water levels to runup, overwash, and coastal flooding

    NASA Astrophysics Data System (ADS)

    Cheriton, Olivia M.; Storlazzi, Curt D.; Rosenberger, Kurt J.

    2016-05-01

    Many low-lying tropical islands are susceptible to sea level rise and often subjected to overwash and flooding during large wave events. To quantify wave dynamics and wave-driven water levels on fringing coral reefs, a 5 month deployment of wave gauges and a current meter was conducted across two shore-normal transects on Roi-Namur Island in the Republic of the Marshall Islands. These observations captured two large wave events that had waves with maximum heights greater than 6 m with peak periods of 16 s over the fore reef. The larger event coincided with a peak spring tide, leading to energetic, highly skewed infragravity (0.04-0.004 Hz) and very low frequency (0.004-0.001 Hz) waves at the shoreline, which reached heights of 1.0 and 0.7 m, respectively. Water surface elevations, combined with wave runup, reached 3.7 m above the reef bed at the innermost reef flat adjacent to the toe of the beach, resulting in flooding of inland areas. This overwash occurred during a 3 h time window that coincided with high tide and maximum low-frequency reef flat wave heights. The relatively low-relief characteristics of this narrow reef flat may further drive shoreline amplification of low-frequency waves due to resonance modes. These results (1) demonstrate how the coupling of high offshore water levels with low-frequency reef flat wave energetics can lead to large impacts along fringing reef-lined shorelines, such as island overwash, and (2) lend support to the hypothesis that predicted higher sea levels will lead to more frequent occurrences of these extreme events, negatively impacting coastal resources and infrastructure.

  7. Somatic mutant frequency at the HPRT locus in children associated with a pediatric cancer cluster linked to exposure to two superfund sites.

    PubMed

    Vacek, Pamela M; Messier, Terri; Rivers, Jami; Sullivan, Linda; O'Neill, J Patrick; Finette, Barry A

    2005-05-01

    The somatic mutant frequency (Mf) of the hypoxanthine phosphoribosyl transferase (HPRT) gene has been widely used as a biomarker for the genotoxic effects of exposure but few studies have found an association with environmental exposures. We measured background Mfs in 49 current and former residents of Dover Township, New Jersey, who were exposed during childhood to industrially contaminated drinking water. The exposed subjects were the siblings of children who developed cancer after residing in Dover Township, where the incidence of childhood cancer has been elevated since 1979. Mfs from this exposed group were compared to Mfs in 43 age-matched, presumably unexposed residents of neighboring communities with no known water contamination and no increased cancer incidence. Statistical comparisons were based on the natural logarithm of Mf (lnMF). The mean Mf for the exposed group did not differ significantly from the unexposed group (3.90 x 10(-6) vs. 5.06 x 10(-6); P = 0.135), but unselected cloning efficiencies were higher in the exposed group (0.55 vs. 0.45; P = 0.005). After adjustment for cloning efficiency, lnMf values were very similar in both groups and age-related increases were comparable to those previously observed in healthy children. The results suggest that HPRT Mf may not be a sensitive biomarker for the genotoxic effects of environmental exposures in children, particularly when substantial time has elapsed since exposure. Copyright 2005 Wiley-Liss, Inc

  8. The link in Linking

    PubMed Central

    Caldwell, Jane C; Chiale, Pablo A; Gonzalez, Mario D; Baranchuk, Adrian

    2013-01-01

    We present 2 cases of the slow-fast form of AVNRT with initially narrow QRS complexes followed by sudden unexpected transition to persistently wide QRS complexes due to aberrant intraventricular conduction. Introduction of a properly timed extrastimulus in one case and critical oscillations in cycle length due to short-long coupling in the second case set the stage for the initial bundle branch block. However, persistence of the aberrancy pattern once the initial event abated was maintained by the "linking" phenomenon. Delayed, retrograde concealed activation from the contralateral bundle branch perpetuated the initial bundle branch block. PMID:23840106

  9. The link in Linking.

    PubMed

    Caldwell, Jane C; Chiale, Pablo A; Gonzalez, Mario D; Baranchuk, Adrian

    2013-05-01

    We present 2 cases of the slow-fast form of AVNRT with initially narrow QRS complexes followed by sudden unexpected transition to persistently wide QRS complexes due to aberrant intraventricular conduction. Introduction of a properly timed extrastimulus in one case and critical oscillations in cycle length due to short-long coupling in the second case set the stage for the initial bundle branch block. However, persistence of the aberrancy pattern once the initial event abated was maintained by the "linking" phenomenon. Delayed, retrograde concealed activation from the contralateral bundle branch perpetuated the initial bundle branch block.

  10. Thin-Film Power Transformers

    NASA Technical Reports Server (NTRS)

    Katti, Romney R.

    1995-01-01

    Transformer core made of thin layers of insulating material interspersed with thin layers of ferromagnetic material. Flux-linking conductors made of thinner nonferromagnetic-conductor/insulator multilayers wrapped around core. Transformers have geometric features finer than those of transformers made in customary way by machining and mechanical pressing. In addition, some thin-film materials exhibit magnetic-flux-carrying capabilities superior to those of customary bulk transformer materials. Suitable for low-cost, high-yield mass production.

  11. Nonlinear transient simulation of transformers

    SciTech Connect

    Pierrat, L.; Tran-Quoc, T. |; Montmeat, A.

    1995-12-31

    In this paper, a nonlinear model of transformer which takes into account both the saturation and the hysteresis is proposed. In order to simulate transient phenomena in transformers, a system of equations is presented. The digital simulation of the energization and de-energization of a three-phase distribution transformer is studied. Ferroresonant phenomena in iron core transformers supplied through capacitive links are presented. Finally, the influence of MOV arresters on overvoltage reduction is investigated.

  12. Thin-Film Power Transformers

    NASA Technical Reports Server (NTRS)

    Katti, Romney R.

    1995-01-01

    Transformer core made of thin layers of insulating material interspersed with thin layers of ferromagnetic material. Flux-linking conductors made of thinner nonferromagnetic-conductor/insulator multilayers wrapped around core. Transformers have geometric features finer than those of transformers made in customary way by machining and mechanical pressing. In addition, some thin-film materials exhibit magnetic-flux-carrying capabilities superior to those of customary bulk transformer materials. Suitable for low-cost, high-yield mass production.

  13. Declining frequency of summertime local-scale precipitation over eastern China from 1970 to 2010 and its potential link to aerosols

    NASA Astrophysics Data System (ADS)

    Guo, Jianping; Su, Tianning; Li, Zhanqing; Miao, Yucong; Li, Jing; Liu, Huan; Xu, Hui; Cribb, Maureen; Zhai, Panmao

    2017-06-01

    Summer precipitation plays critical roles in the energy balance and the availability of fresh water over eastern China. However, little is known regarding the trend in local-scale precipitation (LSP). Here we developed a novel method to determine LSP events in the summer afternoon throughout eastern China from 1970 to 2010 based on hourly gauge measurements. The LSP occurrence hours decrease at an annual rate of 0.25%, which varies considerably by region, ranging from 0.14% over the Yangtze River Delta to 0.56% over the Pearl River Delta. This declining frequency of LSP is generally accompanied by an increase in rain rate of LSP but a decrease in visibility, whose linkage to LSP events was investigated. In particular, more LSP events tended to form when the atmosphere was slightly polluted. Afterward, LSP was suppressed. These findings have important implications for improving our understanding of the climatology of daytime precipitation at local scales.Plain Language SummarySummer precipitation plays critical roles in the energy balance and the availability of fresh water over eastern China. However, the knowledge remains poorly understood regarding the trend of local-scale precipitation (LSP). Long-term hourly gauge data in the summer afternoon throughout eastern China for 1970 to 2010 reveal that LSP occurrence hours decrease at an annual rate of 0.25%, which differs greatly by region, ranging from 0.14% over the Yangtze River Delta to 0.56% over the Pearl River Delta. In contrast, large-scale precipitation events do not show significant increasing/decreasing trends over most regions. Further, concurrent visibility observations exhibit a decreasing trend, whose linkage to declining LSP is investigated. In particular, more LSP events tend to form as the atmosphere is slightly polluted. Afterward, LSP is suppressed. The findings provide deep insight into how precipitation changes over long term from a perspective of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21078900','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21078900"><span>Endoplasmic reticulum stress-mediated apoptosis of EBV-<span class="hlt">transformed</span> B cells by cross-<span class="hlt">linking</span> of CD70 is dependent upon generation of reactive oxygen species and activation of p38 MAPK and JNK pathway.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Park, Ga Bin; Kim, Yeong Seok; Lee, Hyun-Kyung; Song, Hyunkeun; Cho, Dae-Ho; Lee, Wang Jae; Hur, Dae Young</p> <p>2010-12-15</p> <p>CD70 is expressed in normal activated immune cells as well as in several types of tumors. It has been established that anti-CD70 mAb induces complement-dependent death of CD70(+) tumor cells, but how anti-CD70 mAb affects the intrinsic signaling is poorly defined. In this report, we show that ligation of CD70 expressed on EBV-<span class="hlt">transformed</span> B cells using anti-CD70 mAb induced production of reactive oxygen species (ROS) and subsequent apoptosis. We observed an early expression of endoplasmic reticulum (ER) stress response genes that preceded the release of apoptotic molecules from the mitochondria and the cleavage of caspases. CD70-induced apoptosis was inhibited by pretreatment with the ER stress inhibitor salubrinal, ROS quencher N-acetylcysteine, and Ca(2+) chelator BAPTA. We supposed that ROS generation might be the first event of CD70-induced apoptosis because N-acetylcysteine blocked increases of ROS and Ca(2+), but BAPTA did not block ROS generation. We also found that CD70 stimulation activated JNK and p38 MAPK. JNK inhibitor SP600125 and p38 inhibitor SB203580 effectively blocked upregulation of ER stress-related genes and cleavage of caspases. Inhibition of ROS generation completely blocked phosphorylation of JNK and p38 MAPK and induction of ER stress-related genes. Taken together, we concluded that cross-<span class="hlt">linking</span> of CD70 on EBV-<span class="hlt">transformed</span> B cells triggered ER stress-mediated apoptosis via ROS generation and JNK and p38 MAPK pathway activation. Our report reveals alternate mechanisms of direct apoptosis through CD70 signaling and provides data supporting CD70 as a viable target for an Ab-based therapy against EBV-related tumors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18941206','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18941206"><span>Cross-<span class="hlt">linking</span> of B7-H1 on EBV-<span class="hlt">transformed</span> B cells induces apoptosis through reactive oxygen species production, JNK signaling activation, and fasL expression.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Yeong Seok; Park, Ga Bin; Lee, Hyun-Kyung; Song, Hyunkeun; Choi, In-Hak; Lee, Wang Jae; Hur, Dae Young</p> <p>2008-11-01</p> <p>B7-H1 is a newly identified member of the B7 family with important regulatory functions in cell-mediated immune responses, and it is expressed in human immune cells and several tumors. We first observed that expression of surface B7-H1 on B cells was increased during the immortalization process by EBV, which is strongly related to both inflammation and tumorigenesis. Cross-<span class="hlt">linking</span> of B7-H1 on EBV-<span class="hlt">transformed</span> B cells using anti-B7-H1 Ab (clone 130002) induced reactive oxygen species (ROS) generation, mitochondrial disruption, release of apoptotic proteins from mitochondria, and subsequent apoptosis. Inhibition of caspases and ROS generation recovered B7-H1-mediated apoptosis and proteolytic activities of caspase-8, -9, and -3. We observed that B7-H1 stimulation induced both transcription and translation of fasL. ZB4, an antagonistic anti-fas Ab, and NOK-1, an antagonistic anti-fasL Ab, effectively blocked apoptosis without exerting any influence on ROS generation. N-acetylcysteine (NAC) completely blocked the induction of fasL mRNA and protein. We found that B7-H1 stimulation activated the phosphorylation of JNK and c-jun and down-regulated ERK1/2 and p-Akt. NAC blocked the activation of JNK and down-regulation of ERK, but both z-VAD-fmk (N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone) and ZB4 did not inhibit JNK activation of B7-H1 stimulation. SP600125 blocked fasL induction and apoptosis but did not affect ROS generation after B7-H1 stimulation. Taken together, we concluded that B7-H1-mediated apoptosis on EBV-<span class="hlt">transformed</span> B cells may be involved in the induction of fasL, which is evoked by ROS generation and JNK activation after cross-<span class="hlt">linking</span> of B7-H1. These results provide a new concept for understanding reverse signaling through B7-H1 and another mechanism of tumor immunotherapy using anti-B7-H1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5347887','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5347887"><span>Rapid Activation of <span class="hlt">Transforming</span> Growth Factor β–Activated Kinase 1 in Chondrocytes by Phosphorylation and K63‐<span class="hlt">Linked</span> Polyubiquitination Upon Injury to Animal Articular Cartilage</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ismail, Heba M.; Didangelos, Athanasios; Vincent, Tonia L.</p> <p>2017-01-01</p> <p>Objective Mechanical injury to cartilage predisposes to osteoarthritis (OA). Wounding of the articular cartilage surface causes rapid activation of MAP kinases and NF‐κB, mimicking the response to inflammatory cytokines. This study was undertaken to identify the upstream signaling mechanisms involved. Methods Cartilage was injured by dissecting it from the articular surface of porcine metacarpophalangeal (MCP) joints or by avulsing murine proximal femoral epiphyses. Protein phosphorylation was assayed by Western blotting of cartilage lysates. Immunolocalization of phosphorylated activating transcription factor 2 (ATF‐2) and NF‐κB/p65 was detected by confocal microscopy. Messenger RNA (mRNA) was measured by quantitative reverse transcriptase–polymerase chain reaction (qRT‐PCR). Receptor associated protein 80 (RAP‐80) ubiquitin interacting motif agarose was used in a pull‐down assay to obtain K63‐polyubiquitinated proteins. Ubiquitin linkages on immunoprecipitated <span class="hlt">transforming</span> growth factor β–activated kinase 1 (TAK‐1) were analyzed with deubiquitinases. Results Sharp injury to porcine cartilage caused rapid activation of JNK and NF‐κB pathways and the upstream kinases MKK‐4, IKK, and TAK‐1. Pharmacologic inhibition of TAK‐1 in porcine cartilage abolished JNK and NF‐κB activation and reduced the injury‐dependent inflammatory gene response. High molecular weight species of phosphorylated TAK‐1 were induced by injury, indicating its ubiquitination. An overall increase in K63‐<span class="hlt">linked</span> polyubiquitination was detected upon injury, and TAK‐1 was specifically <span class="hlt">linked</span> to K63‐ but not K48‐polyubiquitin chains. In mice, avulsion of wild‐type femoral epiphyses caused similar intracellular signaling that was reduced in cartilage‐specific TAK‐1–null mice. Epiphyseal cartilage of MyD88‐null and TRAF‐6–null mice responded to injury, suggesting the involvement of a ubiquitin E3 ligase other than TRAF‐6. Conclusion</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15640959','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15640959"><span>Early nuclear alterations and immunohistochemical expression of Ki-67, Erb-B2, vascular endothelial growth factor (VEGF), <span class="hlt">transforming</span> growth factor (TGF-beta1) and integrine-<span class="hlt">linked</span> kinase (ILK) two days after tamoxifen in breast carcinoma.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Morena, A M L; Oshima, C T F; Gebrim, L H; Egami, M I; Silva, M R R; Segreto, R A; Giannotti Filho, O; Teixeira, V P C; Segreto, H R C</p> <p>2004-01-01</p> <p>The purpose of the present study was to evaluate breast carcinoma samples before and two days after treatment with tamoxifen in order to analyse early histopathological alterations--particularlynuclear alterations-- as well as immunohistochemical expression of Ki-67, Erb-B2, VEGF, TGF-beta1 and ILK proteins. Twenty one cases of invasive ductal and lobular breast carcinoma were studied. Patients were submitted to biopsy of the lesion and, after confirmation of the diagnosis, they received 20 mg of tamoxifen a day, beginning two days before surgery. The samples obtained during biopsy and after surgery were stained with HE for histopathological diagnosis. Estrogen receptor was positive in 18 cases and negative in 3. The immunohistochemical method was applied for the detection of Ki-67, Erb-B2, protein, vascular endothelial growth factor (VEGF), <span class="hlt">transforming</span> growth factor beta (TGF-beta1) and integrin <span class="hlt">linked</span> kinase (ILK). Two days after tamoxifen treatment, the following results were observed: 1) decrease in the cell volume, chomatine condensation, nucleoli less evident and clearly defined nuclear limits; 2) significant reduction in the expression of Erb-B2 protein and significant increase in the expression of TGF-beta1 protein; 3) expression of others proteins (Ki-67, VEGF and ILK) was not altered during the indicated time frame. Our results suggest that analyzing nuclear alterations and expression of Erb-B2 and TGF-beta1 proteins would be useful to assess the initial response to tamoxifen.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/836810','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/836810"><span>Femtosecond nonlinear spectroscopy at surfaces: Second-harmonic probing of hole burning at the Si(111)7x7 surface and fourier-<span class="hlt">transform</span> sum-<span class="hlt">frequency</span> vibrational spectroscopy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>McGuire, John Andrew</p> <p>2004-11-24</p> <p>The high temporal resolution and broad bandwidth of a femtosecond laser system are exploited in a pair of nonlinear optical studies of surfaces. The dephasing dynamics of resonances associated with the adatom dangling bonds of the Si(111)7 x 7 surface are explored by transient second-harmonic hole burning, a process that can be described as a fourth-order nonlinear optical process. Spectral holes produced by a 100 fs pump pulse at about 800 nm are probed by the second harmonic signal of a 100 fs pulse tunable around 800 nm. The measured spectral holes yield homogeneous dephasing times of a few tens of femtoseconds. Fits with a Lorentzian spectral hole centered at zero probe detuning show a linear dependence of the hole width on pump fluence, which suggests that charge carrier-carrier scattering dominates the dephasing dynamics at the measured excitation densities. Extrapolation of the deduced homogeneous dephasing times to zero excitation density yields an intrinsic dephasing time of {approx} 70 fs. The presence of a secondary spectral hole indicates that scattering of the surface electrons with surface optical phonons at 570 cm<sup>-1</sup> occurs within the first 200 fs after excitation. The broad bandwidth of femtosecond IR pulses is used to perform IR-visible sum <span class="hlt">frequency</span> vibrational spectroscopy. By implementing a Fourier-<span class="hlt">transform</span> technique, we demonstrate the ability to obtain sub-laser-bandwidth spectral resolution. FT-SFG yields a greater signal when implemented with a stretched visible pulse than with a femtosecond visible pulse. However, when compared with multichannel spectroscopy using a femtosecond IR pulse but a narrowband visible pulse, Fourier-<span class="hlt">transform</span> SFG is found to have an inferior signal-to-noise ratio. A mathematical analysis of the signal-to-noise ratio illustrates the constraints on the Fourier-<span class="hlt">transform</span> approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhyA..469..767S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhyA..469..767S"><span><span class="hlt">Link</span> direction for <span class="hlt">link</span> prediction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shang, Ke-ke; Small, Michael; Yan, Wei-sheng</p> <p>2017-03-01</p> <p>Almost all previous studies on <span class="hlt">link</span> prediction have focused on using the properties of the network to predict the existence of <span class="hlt">links</span> between pairs of nodes. Unfortunately, previous methods rarely consider the role of <span class="hlt">link</span> direction for <span class="hlt">link</span> prediction. In fact, many real-world complex networks are directed and ignoring the <span class="hlt">link</span> direction will mean overlooking important information. In this study, we propose a phase-dynamic algorithm of the directed network nodes to analyse the role of <span class="hlt">link</span> directions and demonstrate that the bi-directional <span class="hlt">links</span> and the one-directional <span class="hlt">links</span> have different roles in <span class="hlt">link</span> prediction and network structure formation. From this, we propose new directional prediction methods and use six real networks to test our algorithms. In real networks, we find that compared to a pair of nodes which are connected by a one-directional <span class="hlt">link</span>, a pair of nodes which are connected by a bi-directional <span class="hlt">link</span> always have higher probabilities to connect to the common neighbours with only bi-directional <span class="hlt">links</span> (or conversely by one-directional <span class="hlt">links</span>). We suggest that, in the real networks, the bi-directional <span class="hlt">links</span> will generally be more informative for <span class="hlt">link</span> prediction and network structure formation. In addition, we propose a new directional randomized algorithm to demonstrate that the direction of the <span class="hlt">links</span> plays a significant role in <span class="hlt">link</span> prediction and network structure formation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23258020','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23258020"><span>Fiber-wireless transmission system of 108  Gb/sdata over 80 km fiber and 2×2multiple-input multiple-output wireless <span class="hlt">links</span> at 100 GHz W-band <span class="hlt">frequency</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Xinying; Dong, Ze; Yu, Jianjun; Chi, Nan; Shao, Yufeng; Chang, G K</p> <p>2012-12-15</p> <p>We experimentally demonstrate a seamlessly integrated fiber-wireless system that delivers a 108  Gb/s signal through 80 km fiber and 1 m wireless transport over free space at 100 GHz adopting polarization-division-multiplexing quadrature-phase-shift-keying (PDM-QPSK) modulation and heterodyning coherent detection. The X- and Y-polarization components of the optical PDM-QPSK baseband signal are simultaneously upconverted to 100 GHz wireless carrier by optical polarization-diversity heterodyne beating, and then independently transmitted and received by two pairs of transmitter and receiver antennas, which form a 2×2 multiple-input multiple-output wireless <span class="hlt">link</span>. At the wireless receiver, two-stage downconversion is performed firstly in the analog domain based on balanced mixer and sinusoidal radio <span class="hlt">frequency</span> signal, and then in the digital domain based on digital signal processing (DSP). Polarization demultiplexing is realized by the constant modulus algorithm in the DSP part at the receiver. The bit-error ratio for the 108  Gb/s PDM-QPSK signal is less than the pre-forward-error-correction threshold of 3.8×10(-3) after both 1 m wireless delivery at 100 GHz and 80 km single-mode fiber-28 transmission. To our knowledge, this is the first demonstration to realize 100  Gb/s signal delivery through both fiber and wireless <span class="hlt">links</span> at 100 GHz.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800024931','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800024931"><span>Experimental optical fiber communications <span class="hlt">link</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lutes, G. F.</p> <p>1980-01-01</p> <p>An optical fiber communications <span class="hlt">link</span> 1.5 kilometers in length was installed between the Interim <span class="hlt">Frequency</span> Standard Test Facility and the Timing and <span class="hlt">Frequency</span> Systems Research Laboratory at JPL. It is being used to develop optical fiber technology for use in the DSN and particularly for precise time and <span class="hlt">frequency</span> distribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=electrical&pg=3&id=EJ1044174','ERIC'); return false;" href="https://eric.ed.gov/?q=electrical&pg=3&id=EJ1044174"><span><span class="hlt">Transformer</span> Impedance Reflection Demonstration</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Layton, William</p> <p>2014-01-01</p> <p>Questions often arise as to how a device attached to a <span class="hlt">transformer</span> can draw power from the electrical power grid since it seems that the primary and secondary are not connected to one another. However, a closer look at how the primary and secondary are <span class="hlt">linked</span> together magnetically and a consideration of the role of Lenz's law in this linkage…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=bourdieu&pg=4&id=EJ1118868','ERIC'); return false;" href="https://eric.ed.gov/?q=bourdieu&pg=4&id=EJ1118868"><span>Education as Habitus <span class="hlt">Transformations</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>von Rosenberg, Florian</p> <p>2016-01-01</p> <p>Unlike a conventional reading of Bourdieu, this article focuses on his work with regard to the <span class="hlt">transformation</span> of social structure. In the context of a rereading, from an educational theory perspective, the article proposes an approach that allows for the <span class="hlt">linking</span> of empirically informed social theory, on the one hand, and biography research…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=biography&pg=3&id=EJ1118868','ERIC'); return false;" href="http://eric.ed.gov/?q=biography&pg=3&id=EJ1118868"><span>Education as Habitus <span class="hlt">Transformations</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>von Rosenberg, Florian</p> <p>2016-01-01</p> <p>Unlike a conventional reading of Bourdieu, this article focuses on his work with regard to the <span class="hlt">transformation</span> of social structure. In the context of a rereading, from an educational theory perspective, the article proposes an approach that allows for the <span class="hlt">linking</span> of empirically informed social theory, on the one hand, and biography research…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Worship&pg=5&id=EJ989040','ERIC'); return false;" href="https://eric.ed.gov/?q=Worship&pg=5&id=EJ989040"><span>Teaching, Caring, and <span class="hlt">Transformation</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Nieto, Sonia</p> <p>2012-01-01</p> <p>Educator Bell Hooks acknowledged the fundamental truth that teaching, caring, and <span class="hlt">transformation</span> are closely <span class="hlt">linked</span>, that is, that true teaching must be accompanied by a deep level of care in order for learning to take place. No matter how young or old, no matter the subject matter, and no matter where teaching and learning take place--a…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=impedance&id=EJ1044174','ERIC'); return false;" href="http://eric.ed.gov/?q=impedance&id=EJ1044174"><span><span class="hlt">Transformer</span> Impedance Reflection Demonstration</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Layton, William</p> <p>2014-01-01</p> <p>Questions often arise as to how a device attached to a <span class="hlt">transformer</span> can draw power from the electrical power grid since it seems that the primary and secondary are not connected to one another. However, a closer look at how the primary and secondary are <span class="hlt">linked</span> together magnetically and a consideration of the role of Lenz's law in this linkage…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=blacksmith&pg=2&id=ED220845','ERIC'); return false;" href="http://eric.ed.gov/?q=blacksmith&pg=2&id=ED220845"><span>Forging <span class="hlt">Links</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Stewig, John Warren</p> <p></p> <p>Blacksmiths and their craft have changed with the times, and as times change for teachers, they too should be forgers of <span class="hlt">links</span>. Teacher-to-teacher <span class="hlt">links</span> should extend beyond the faculty lounge to support systems and active groups of individuals concerned about each other. Another personal <span class="hlt">link</span> can be made by developing a grade level, system-wide…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27888883','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27888883"><span><span class="hlt">Transformed</span> Lymphoma.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Anderson, Mary Ann; Blombery, Piers; Seymour, John F</p> <p>2016-12-01</p> <p><span class="hlt">Transformed</span> lymphoma is a complex syndrome that encompasses an array of different underlying low-grade lymphoproliferative conditions <span class="hlt">transforming</span> into more aggressive disease as manifest by morphologic, clinical, and genetic features. Over the last decade, advances in chemoimmunotherapy have led to new options. Knowledge surrounding the genetic changes driving the process of <span class="hlt">transformation</span> is leading to novel targeted therapies. This article focuses on the <span class="hlt">transformation</span> of chronic lymphocytic leukemia and follicular lymphoma into diffuse large B-cell lymphoma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title47-vol5/pdf/CFR-2014-title47-vol5-sec87-287.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title47-vol5/pdf/CFR-2014-title47-vol5-sec87-287.pdf"><span>47 CFR 87.287 - <span class="hlt">Frequencies</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 47 Telecommunication 5 2014-10-01 2014-10-01 false <span class="hlt">Frequencies</span>. 87.287 Section 87.287... Data <span class="hlt">Link</span> Land Test Stations § 87.287 <span class="hlt">Frequencies</span>. (a) The <span class="hlt">frequencies</span> assignable to aircraft data <span class="hlt">link</span>..., 136.925 MHz, 136.950 MHz, and 136.975 MHz. Interstitial <span class="hlt">frequencies</span> separated by 8.33 kilohertz from...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1024701','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1024701"><span>Wideband FM Demodulation and Multirate <span class="hlt">Frequency</span> <span class="hlt">Transformations</span></span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2016-12-15</p> <p>University of New Mexico 1700 Lomas Blvd NE Albuquerque, NM 87106-3807 15 Dec 2016 Final Report APPROVED FOR PUBLIC RELEASE; DISTRIBUTION IS...NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER University of New Mexico 1700 Lomas Blvd NE Albuquerque, NM 87106-3807 9. SPONSORING...Edition, Pren- tice Hall, New York, 1999. [9] F. F. Kuo and J. F. Kaiser, “System analysis by digital computer,” John Wiley Publication, 1966. [10] B</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017CNSNS..44...19D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017CNSNS..44...19D"><span>A new fractional wavelet <span class="hlt">transform</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dai, Hongzhe; Zheng, Zhibao; Wang, Wei</p> <p>2017-03-01</p> <p>The fractional Fourier <span class="hlt">transform</span> (FRFT) is a potent tool to analyze the time-varying signal. However, it fails in locating the fractional Fourier domain (FRFD)-<span class="hlt">frequency</span> contents which is required in some applications. A novel fractional wavelet <span class="hlt">transform</span> (FRWT) is proposed to solve this problem. It displays the time and FRFD-<span class="hlt">frequency</span> information jointly in the time-FRFD-<span class="hlt">frequency</span> plane. The definition, basic properties, inverse <span class="hlt">transform</span> and reproducing kernel of the proposed FRWT are considered. It has been shown that an FRWT with proper order corresponds to the classical wavelet <span class="hlt">transform</span> (WT). The multiresolution analysis (MRA) associated with the developed FRWT, together with the construction of the orthogonal fractional wavelets are also presented. Three applications are discussed: the analysis of signal with time-varying <span class="hlt">frequency</span> content, the FRFD spectrum estimation of signals that involving noise, and the construction of fractional Harr wavelet. Simulations verify the validity of the proposed FRWT.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27943351','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27943351"><span>Germline mosaicism is a pitfall in PGD for X-<span class="hlt">linked</span> disorders. Single sperm typing detects very low <span class="hlt">frequency</span> paternal gonadal mosaicism in a case of recurrent chondrodysplasia punctata misattributed to a maternal origin.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Viart, Victoria; Willems, Marjolaine; Ishmukhametova, Aliya; Dufernez, Fabienne; Anahory, Tal; Hamamah, Samir; Schmitt, Sébastien; Claustres, Mireille; Girardet, Anne</p> <p>2017-02-01</p> <p>This manuscript presents a molecularly demonstrated gonadal mosaicism from paternal origin for X-<span class="hlt">linked</span> dominant chondrodysplasia punctata by single sperm typing. A couple who had experienced two medical terminations of pregnancy of female fetuses was referred to our pre-implantation genetic diagnosis (PGD) centre with the diagnosis of maternally derived gonadal mosaicism. Indeed, genetic analyses of different DNA samples - including semen - from the healthy parents failed to detect the variant found in the fetuses. Six embryos, all male, were obtained during the PGD cycle. The causative variant was not detected in any embryo, whereas five embryos had inherited the 'at-risk' maternal haplotype. The assumption of a maternal gonadal mosaicism was still possible, but this finding allowed us to consider the possibility of a paternal rather than maternal gonadal mosaicism. It prompted us to perform extensive single sperm analyses, demonstrating a low-<span class="hlt">frequency</span> paternal germline mosaicism, which led to completely different haplotype phasing and PGD counselling. In conclusion, this case further exemplifies that germline mosaicism is a pitfall in PGD where diagnosis largely relies on linkage analysis and suggests that tracing the parental inheritance through polar body analysis and/or single sperm typing experiments is of major importance for adequate genetic counselling and accurate PGD. © 2016 John Wiley & Sons, Ltd. © 2016 John Wiley & Sons, Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3686866','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3686866"><span><span class="hlt">Link</span> Clustering with Extended <span class="hlt">Link</span> Similarity and EQ Evaluation Division</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Huang, Lan; Wang, Guishen; Wang, Yan; Blanzieri, Enrico; Su, Chao</p> <p>2013-01-01</p> <p><span class="hlt">Link</span> Clustering (LC) is a relatively new method for detecting overlapping communities in networks. The basic principle of LC is to derive a <span class="hlt">transform</span> matrix whose elements are composed of the <span class="hlt">link</span> similarity of neighbor <span class="hlt">links</span> based on the Jaccard distance calculation; then it applies hierarchical clustering to the <span class="hlt">transform</span> matrix and uses a measure of partition density on the resulting dendrogram to determine the cut level for best community detection. However, the original <span class="hlt">link</span> clustering method does not consider the <span class="hlt">link</span> similarity of non-neighbor <span class="hlt">links</span>, and the partition density tends to divide the communities into many small communities. In this paper, an Extended <span class="hlt">Link</span> Clustering method (ELC) for overlapping community detection is proposed. The improved method employs a new <span class="hlt">link</span> similarity, Extended <span class="hlt">Link</span> Similarity (ELS), to produce a denser <span class="hlt">transform</span> matrix, and uses the maximum value of EQ (an extended measure of quality of modularity) as a means to optimally cut the dendrogram for better partitioning of the original network space. Since ELS uses more <span class="hlt">link</span> information, the resulting <span class="hlt">transform</span> matrix provides a superior basis for clustering and analysis. Further, using the EQ value to find the best level for the hierarchical clustering dendrogram division, we obtain communities that are more sensible and reasonable than the ones obtained by the partition density evaluation. Experimentation on five real-world networks and artificially-generated networks shows that the ELC method achieves higher EQ and In-group Proportion (IGP) values. Additionally, communities are more realistic than those generated by either of the original LC method or the classical CPM method. PMID:23840390</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4785364','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4785364"><span>Predicting missing <span class="hlt">links</span> and identifying spurious <span class="hlt">links</span> via likelihood analysis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Pan, Liming; Zhou, Tao; Lü, Linyuan; Hu, Chin-Kun</p> <p>2016-01-01</p> <p>Real network data is often incomplete and noisy, where <span class="hlt">link</span> prediction algorithms and spurious <span class="hlt">link</span> identification algorithms can be applied. Thus far, it lacks a general method to <span class="hlt">transform</span> network organizing mechanisms to <span class="hlt">link</span> prediction algorithms. Here we use an algorithmic framework where a network’s probability is calculated according to a predefined structural Hamiltonian that takes into account the network organizing principles, and a non-observed <span class="hlt">link</span> is scored by the conditional probability of adding the <span class="hlt">link</span> to the observed network. Extensive numerical simulations show that the proposed algorithm has remarkably higher accuracy than the state-of-the-art methods in uncovering missing <span class="hlt">links</span> and identifying spurious <span class="hlt">links</span> in many complex biological and social networks. Such method also finds applications in exploring the underlying network evolutionary mechanisms. PMID:26961965</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26961965','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26961965"><span>Predicting missing <span class="hlt">links</span> and identifying spurious <span class="hlt">links</span> via likelihood analysis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pan, Liming; Zhou, Tao; Lü, Linyuan; Hu, Chin-Kun</p> <p>2016-03-10</p> <p>Real network data is often incomplete and noisy, where <span class="hlt">link</span> prediction algorithms and spurious <span class="hlt">link</span> identification algorithms can be applied. Thus far, it lacks a general method to <span class="hlt">transform</span> network organizing mechanisms to <span class="hlt">link</span> prediction algorithms. Here we use an algorithmic framework where a network's probability is calculated according to a predefined structural Hamiltonian that takes into account the network organizing principles, and a non-observed <span class="hlt">link</span> is scored by the conditional probability of adding the <span class="hlt">link</span> to the observed network. Extensive numerical simulations show that the proposed algorithm has remarkably higher accuracy than the state-of-the-art methods in uncovering missing <span class="hlt">links</span> and identifying spurious <span class="hlt">links</span> in many complex biological and social networks. Such method also finds applications in exploring the underlying network evolutionary mechanisms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980217139','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980217139"><span>Radio <span class="hlt">Links</span> for the NASA ABTS</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jeutter, Dean C.</p> <p>1996-01-01</p> <p>The report discusses: (1) Determination Out-<span class="hlt">Link</span> <span class="hlt">Frequency</span> Shift Keying (FSK) Bandwidth. (2) Development FSK Out-<span class="hlt">link</span> Transmitter. (3) Development Wideband Out-<span class="hlt">link</span> FSK Receiver. (4) Development OOK In-<span class="hlt">Link</span> Transmitter. (5) Development OOK In-<span class="hlt">Link</span> Receiver. and (6) Marry Out-<span class="hlt">Link</span> & In-<span class="hlt">Link</span> Components. Out-<span class="hlt">link</span> FSK Bandwidth preliminary in-<span class="hlt">link</span> transmitter were accomplished in Summer 1995 visit. The calculation of FSK bandwidth is repeated in these notes. Spectrum analyzer measurements of the actual FSK spectrum agree well with the calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10323E..3SX','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10323E..3SX"><span>High spatial resolution multiplexing of fiber Bragg gratings using single-arm <span class="hlt">frequency</span>-shifted interferometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiong, Zeng; Zhou, Ciming; Guo, Huiyong; Fan, Dian; Ou, Yiwen; Liu, Yi; Sun, Chunran; Qian, Li</p> <p>2017-04-01</p> <p>We demonstrate a high spatial resolution multiplexing scheme for fiber Bragg grating (FBG) sensors based on single-arm <span class="hlt">frequency</span>-shifted interferometry (SA-FSI). The SA-FSI system uses an incoherent broadband source, a slow detector, and an electro-optic modulator (EOM). By sweeping the <span class="hlt">frequency</span> of EOM and taking the fast Fourier <span class="hlt">transform</span> (FFT) of the interference signal, we resolved the locations of FBGs distributed both in parallel and in series along fiber <span class="hlt">links</span> despite their reflection spectral overlap. Eighteen weak FBGs ( 5% reflectivity) separated by 0.1 m were clearly resolved experimentally, sweeping EOM modulation <span class="hlt">frequency</span> in the range of 2-11 GHz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013cpgt.book..113S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013cpgt.book..113S"><span>Fourier <span class="hlt">Transformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scherer, Philipp O. J.</p> <p></p> <p>Fourier <span class="hlt">transformation</span> is a very important tool for signal analysis but also helpful to simplify the solution of differential equations or the calculation of convolution integrals. An important numerical method is the discrete Fourier <span class="hlt">transformation</span> which can be used for trigonometric interpolation and also as a numerical approximation to the continuous Fourier integral. It can be realized efficiently by Goertzel's algorithm or the family of fast Fourier <span class="hlt">transformation</span> methods. For real valued even functions the computationally simpler discrete cosine <span class="hlt">transformation</span> can be applied. Several computer experiments demonstrate the principles of trigonometric interpolation and nonlinear filtering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=magnetism&pg=7&id=EJ769547','ERIC'); return false;" href="https://eric.ed.gov/?q=magnetism&pg=7&id=EJ769547"><span><span class="hlt">Transformers</span> and the Electric Utility System</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Roman, Harry T.</p> <p>2005-01-01</p> <p>For electric energy to get from the generating station to a home, it must pass through a <span class="hlt">transformer</span>, a device that can change voltage levels easily. This article describes how <span class="hlt">transformers</span> work, covering the following topics: (1) the magnetism-electricity <span class="hlt">link</span>; (2) <span class="hlt">transformer</span> basics; (3) the energy seesaw; (4) the turns ratio rule; and (5)…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Magnetism&pg=6&id=EJ769547','ERIC'); return false;" href="http://eric.ed.gov/?q=Magnetism&pg=6&id=EJ769547"><span><span class="hlt">Transformers</span> and the Electric Utility System</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Roman, Harry T.</p> <p>2005-01-01</p> <p>For electric energy to get from the generating station to a home, it must pass through a <span class="hlt">transformer</span>, a device that can change voltage levels easily. This article describes how <span class="hlt">transformers</span> work, covering the following topics: (1) the magnetism-electricity <span class="hlt">link</span>; (2) <span class="hlt">transformer</span> basics; (3) the energy seesaw; (4) the turns ratio rule; and (5)…</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/2769731','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/2769731"><span>A shunt-excited inductive power <span class="hlt">link</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sylvan, K; Jordan, J R; Whittington, H W</p> <p>1989-01-01</p> <p>An alternative derivation of the separation-insensitive property of series-excited self-oscillating inductive power transfer circuits is presented. This analysis is based on network theory and does not include the explicit determination of <span class="hlt">frequency</span> as a step in the derivation. The separation-insensitivity principle is extended to shunt-excited <span class="hlt">links</span> which exhibit a theoretical voltage transfer function of unity while the coupling factor exceeds the reciprocal of the secondary quality factor. This requires the inclusion of a series resistor in the primary resonator's capacitive arm. Series RC elements are replaced by parallel forms in both the primary and secondary; this provides a more convenient output impedance level without the need for another <span class="hlt">transformer</span>. A demonstration circuit is described and tested. It is found that separation-insensitivity occurs while the coupling factor exceeds the reciprocal of the loaded secondary quality factor. Somewhat inferior response is obtained from a simpler circuit having no added resistances in the primary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT.......365B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT.......365B"><span>Power Electronic <span class="hlt">Transformer</span> based Three-Phase PWM AC Drives</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Basu, Kaushik</p> <p></p> <p>A <span class="hlt">Transformer</span> is used to provide galvanic isolation and to connect systems at different voltage levels. It is one of the largest and most expensive component in most of the high voltage and high power systems. Its size is inversely proportional to the operating <span class="hlt">frequency</span>. The central idea behind a power electronic <span class="hlt">transformer</span> (PET) also known as solid state <span class="hlt">transformer</span> is to reduce the size of the <span class="hlt">transformer</span> by increasing the <span class="hlt">frequency</span>. Power electronic converters are used to change the <span class="hlt">frequency</span> of operation. Steady reduction in the cost of the semiconductor switches and the advent of advanced magnetic materials with very low loss density and high saturation flux density implies economic viability and feasibility of a design with high power density. Application of PET is in generation of power from renewable energy sources, especially wind and solar. Other important application include grid tied inverters, UPS e.t.c. In this thesis non-resonant, single stage, bi-directional PET is considered. The main objective of this converter is to generate adjustable speed and magnitude pulse width modulated (PWM) ac waveforms from an ac or dc grid with a high <span class="hlt">frequency</span> ac <span class="hlt">link</span>. The windings of a high <span class="hlt">frequency</span> <span class="hlt">transformer</span> contains leakage inductance. Any switching transition of the power electronic converter connecting the inductive load and the <span class="hlt">transformer</span> requires commutation of leakage energy. Commutation by passive means results in power loss, decrease in the <span class="hlt">frequency</span> of operation, distortion in the output voltage waveform, reduction in reliability and power density. In this work a source based partially loss-less commutation of leakage energy has been proposed. This technique also results in partial soft-switching. A series of converters with novel PWM strategies have been proposed to minimize the <span class="hlt">frequency</span> of leakage inductance commutation. These PETs achieve most of the important features of modern PWM ac drives including 1) Input power factor correction, 2) Common</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Denning&pg=2&id=EJ830150','ERIC'); return false;" href="http://eric.ed.gov/?q=Denning&pg=2&id=EJ830150"><span><span class="hlt">Transformational</span> Events</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Denning, Peter J.; Hiles, John E.</p> <p>2006-01-01</p> <p><span class="hlt">Transformational</span> Events is a new pedagogic pattern that explains how innovations (and other <span class="hlt">transformations</span>) happened. The pattern is three temporal stages: an interval of increasingly unsatisfactory ad hoc solutions to a persistent problem (the "mess"), an offer of an invention or of a new way of thinking, and a period of widespread adoption and…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=English+AND+kids&pg=6&id=EJ767086','ERIC'); return false;" href="https://eric.ed.gov/?q=English+AND+kids&pg=6&id=EJ767086"><span>Reading <span class="hlt">Transformation</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Reeves, Melinda</p> <p>2006-01-01</p> <p>The parents of students who attend Decatur High School thought that there was little hope of their kids going on to college. After a year or so in Decatur's reading program, their sons and daughters were both <span class="hlt">transformed</span> and college bound. In this article, the author describes how Decatur was able to successfully <span class="hlt">transform</span> their students. Seven…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=science+AND+education+AND+kids&pg=5&id=EJ767086','ERIC'); return false;" href="http://eric.ed.gov/?q=science+AND+education+AND+kids&pg=5&id=EJ767086"><span>Reading <span class="hlt">Transformation</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Reeves, Melinda</p> <p>2006-01-01</p> <p>The parents of students who attend Decatur High School thought that there was little hope of their kids going on to college. After a year or so in Decatur's reading program, their sons and daughters were both <span class="hlt">transformed</span> and college bound. In this article, the author describes how Decatur was able to successfully <span class="hlt">transform</span> their students. Seven…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=new+AND+inventions&pg=5&id=EJ830150','ERIC'); return false;" href="https://eric.ed.gov/?q=new+AND+inventions&pg=5&id=EJ830150"><span><span class="hlt">Transformational</span> Events</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Denning, Peter J.; Hiles, John E.</p> <p>2006-01-01</p> <p><span class="hlt">Transformational</span> Events is a new pedagogic pattern that explains how innovations (and other <span class="hlt">transformations</span>) happened. The pattern is three temporal stages: an interval of increasingly unsatisfactory ad hoc solutions to a persistent problem (the "mess"), an offer of an invention or of a new way of thinking, and a period of widespread adoption and…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ124667.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ124667.pdf"><span>Community <span class="hlt">Links</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Nelson, Mary</p> <p>1975-01-01</p> <p>At Moraine Valley Community College (Illinois), a chain of events, programs, activities, and services has <span class="hlt">linked</span> the college and community in such areas as fine arts, ethnic groups, public services, community action, community service, and community education. (Author/NHM)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010dmak.book..355D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010dmak.book..355D"><span><span class="hlt">Link</span> Analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Donoho, Steve</p> <p></p> <p><span class="hlt">Link</span> analysis is a collection of techniques that operate on data that can be represented as nodes and <span class="hlt">links</span>. This chapter surveys a variety of techniques including subgraph matching, finding cliques and K-plexes, maximizing spread of influence, visualization, finding hubs and authorities, and combining with traditional techniques (classification, clustering, etc). It also surveys applications including social network analysis, viral marketing, Internet search, fraud detection, and crime prevention.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6893649','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6893649"><span>[<span class="hlt">Transformation</span> toughening</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rafa, M.J.</p> <p>1993-04-19</p> <p>In NiAl, we have succeeded in determining the complete Ginzburg-Landau strain free energy function necessary to model the cubic to tetragonal martensite <span class="hlt">transformation</span> in a sample of any size. We believe that this is the first time that the parameters of a Ginzburg-Landau functional and the complete strain spinodal for any three-dimensional displacive <span class="hlt">transformation</span> were used in simulating the <span class="hlt">transformation</span> near a crack tip under Mode I loading; the <span class="hlt">transformation</span> pattern and toughening are different from standard <span class="hlt">transformation</span> toughening theories. Furthermore, the strain spinodal has an approximately conical shape which can be specified by two material dependent experimentally accessible parameters, rather than the ellipsoidal shape in standard theories. Stress induced martensitic <span class="hlt">transformation</span> in a polycrystalline sample of NiAl was simulated. In the ZrO[sub 2] system, first principles calculations to determine the semi-empirical potentials for simulating the cubic-tetragonal and tetragonal-monoclinic <span class="hlt">transformations</span> have been started by doing a more elaborate total energy calculation.In the Al[sub 2]0[sub 3] system, we have discovered that the first principles calculations and semi-empirical potentials have just been completed byanother group in England which we will use instead to base our molecular dynamics simulations on.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6197083','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6197083"><span>Lightweight <span class="hlt">transformer</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Swallom, D.W.; Enos, G.</p> <p>1990-05-01</p> <p>The technical effort described in this report relates to the program that was performed to design, fabricate, and test a lightweight <span class="hlt">transformer</span> for Strategic Defense Initiative Organization (SDIO) mission requirements. The objectives of this program were two-fold: (1) design and fabricate a lightweight <span class="hlt">transformer</span> using liquid hydrogen as the coolant; and (2) test the completed <span class="hlt">transformer</span> assembly with a low voltage, dc power source. Although the full power testing with liquid helium was not completed, the program demonstrated the viability of the design approach. The lightweight <span class="hlt">transformer</span> was designed and fabricated, and low and moderate power testing was completed. The <span class="hlt">transformer</span> is a liquid hydrogen cooled air core <span class="hlt">transformer</span> that uses thin copper for its primary and secondary windings. The winding mass was approximately 12 kg, or 0.03 kg/kW. Further refinements of the design to a partial air core <span class="hlt">transformer</span> could potentially reduce the winding mass to as low as 4 or 5 kg, or 0.0125 kg/kW. No attempt was made on this program to reduce the mass of the related structural components or cryogenic container. 8 refs., 39 figs., 2 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995ApOpt..34..828Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995ApOpt..34..828Z"><span>Optical implementation of the Bode <span class="hlt">transform</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zalevsky, Zeev; Mendlovic, David</p> <p>1995-02-01</p> <p>The Bode <span class="hlt">transformation</span> is a useful tool for determining and analyzing the <span class="hlt">frequency</span> response of a system. It has a special importance for detecting the resonance <span class="hlt">frequencies</span> of a linear system that, because of its linearity, can be totally characterized by its impulse response. An optical configuration that implements the Bode <span class="hlt">transformation</span> of a function is suggested and demonstrated experimentally.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4068157','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4068157"><span>Dynamics of a combined medea-underdominant population <span class="hlt">transformation</span> system</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2014-01-01</p> <p>Background Transgenic constructs intended to be stably established at high <span class="hlt">frequencies</span> in wild populations have been demonstrated to “drive” from low <span class="hlt">frequencies</span> in experimental insect populations. <span class="hlt">Linking</span> such population <span class="hlt">transformation</span> constructs to genes which render them unable to transmit pathogens could eventually be used to stop the spread of vector-borne diseases like malaria and dengue. Results Generally, population <span class="hlt">transformation</span> constructs with only a single transgenic drive mechanism have been envisioned. Using a theoretical modelling approach we describe the predicted properties of a construct combining autosomal Medea and underdominant population <span class="hlt">transformation</span> systems. We show that when combined they can exhibit synergistic properties which in broad circumstances surpass those of the single systems. Conclusion With combined systems, intentional population <span class="hlt">transformation</span> and its reversal can be achieved readily. Combined constructs also enhance the capacity to geographically restrict transgenic constructs to targeted populations. It is anticipated that these properties are likely to be of particular value in attracting regulatory approval and public acceptance of this novel technology. PMID:24884575</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA614914','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA614914"><span>Flexible Data <span class="hlt">Link</span></span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2015-04-01</p> <p>continuously-interleaved Reed- Solomon scheme with 8% overhead has the best trade-off of performance (net coding gain) and overhead. Therefore, this is...disparity between attenuation at sea level versus at a 9150 meter altitude. As the Flexible Data <span class="hlt">Link</span> system is an airborne asset which may operate...Quadrature Amplitude Modulation QPSK Quadrature Phase Shift Key RF Radio <span class="hlt">Frequency</span> RS Reed- Solomon S&E Scientist & Engineers SFP Small Form-factor</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013NatCC...3..692K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013NatCC...3..692K"><span>Triple <span class="hlt">transformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khan, Farrukh I.; Schinn, Dustin S.</p> <p>2013-08-01</p> <p>A new business plan that enables policy <span class="hlt">transformation</span> and resource mobilization at the national and international level, while improving access to resources, will allow the Green Climate Fund to integrate development goals and action on climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22094611','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22094611"><span><span class="hlt">Transformational</span> leadership.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Luzinski, Craig</p> <p>2011-12-01</p> <p>This month, the director of the Magnet Recognition Program® takes an in-depth look at the Magnet® model component <span class="hlt">transformational</span> leadership. The author examines the expectations for Magnet organizations around this component. What are the qualities that make a nursing leader truly <span class="hlt">transformational</span>, and what is the best approach to successfully lead a healthcare organization through today's volatile healthcare environment?</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11202440','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11202440"><span>Agrobacterium-mediated sorghum <span class="hlt">transformation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhao, Z Y; Cai, T; Tagliani, L; Miller, M; Wang, N; Pang, H; Rudert, M; Schroeder, S; Hondred, D; Seltzer, J; Pierce, D</p> <p>2000-12-01</p> <p>Agrobacterium tumefaciens was used to genetically <span class="hlt">transform</span> sorghum. Immature embryos of a public (P898012) and a commercial line (PHI391) of sorghum were used as the target explants. The Agrobacterium strain used was LBA4404 carrying a 'Super-binary' vector with a bar gene as a selectable marker for herbicide resistance in the plant cells. A series of parameter tests was used to establish a baseline for conditions to be used in stable <span class="hlt">transformation</span> experiments. A number of different <span class="hlt">transformation</span> conditions were tested and a total of 131 stably <span class="hlt">transformed</span> events were produced from 6175 embryos in these two sorghum lines. Statistical analysis showed that the source of the embryos had a very significant impact on <span class="hlt">transformation</span> efficiency, with field-grown embryos producing a higher <span class="hlt">transformation</span> <span class="hlt">frequency</span> than greenhouse-grown embryos. Southern blot analysis of DNA from leaf tissues of T0 plants confirmed the integration of the T-DNA into the sorghum genome. Mendelian segregation in the T1 generation was confirmed by herbicide resistance screening. This is the first report of successful use of Agrobacterium for production of stably <span class="hlt">transformed</span> sorghum plants. The Agrobacterium method we used yields a higher <span class="hlt">frequency</span> of stable <span class="hlt">transformation</span> that other methods reported previously.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/7008679','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/7008679"><span>Helically <span class="hlt">linked</span> mirror arrangement</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ranjan, P.</p> <p>1986-08-01</p> <p>A scheme is described for helical <span class="hlt">linking</span> of mirror sections, which endeavors to combine the better features of toroidal and mirror devices by eliminating the longitudinal loss of mirror machines, having moderately high average ..beta.. and steady state operation. This scheme is aimed at a device, with closed magnetic surfaces having rotational <span class="hlt">transform</span> for equilibrium, one or more axisymmetric straight sections for reduced radial loss, a simple geometrical axis for the <span class="hlt">links</span> and an overall positive magnetic well depth for stability. We start by describing several other attempts at <span class="hlt">linking</span> of mirror sections, made both in the past and the present. Then a description of our helically <span class="hlt">linked</span> mirror scheme is given. This example has three identical straight sections connected by three sections having helical geometric axes. A theoretical analysis of the magnetic field and single-particle orbits in them leads to the conclusion that most of the passing particles would be confined in the device and they would have orbits independent of pitch angle under certain conditions. Numerical results are presented, which agree well with the theoretical results as far as passing particle orbits are concerned.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18055372','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18055372"><span>Psychoanalytic <span class="hlt">transformations</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Riolo, Fernando</p> <p>2007-12-01</p> <p>The author describes how Bion took Freud's conception of dreams as a form of thought and used it as the basis of his theory of <span class="hlt">transformations</span>. Bion developed an expanded theory of 'dream thought', understood as a process of selection and <span class="hlt">transformation</span> of sensory and emotional experiences. In this theory, the work of analysis is in turn conceived as a process not only of deciphering symbols, of revealing already existing unconscious meanings, but also of symbol production--of a process for generating thoughts and conferring meaning on experiences that have never been conscious and never been repressed because they have never been 'thought'. Analysis, in its specific operational sense, becomes a system of <span class="hlt">transformation</span> whereby unconscious somatopsychic processes acquire the conditions for representability and become capable of translation into thoughts, words and interpretations. The rules of <span class="hlt">transformation</span> applied by the patient in his representations and those applied by the analyst in his interpretations have the same importance for the analytic process as those described by Freud for the process of dreaming. The author discusses the broad categories of <span class="hlt">transformation</span> adduced by Bion (rigid motion, projective, and in hallucinosis) and introduces some further distinctions within them.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23280540','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23280540"><span>High-<span class="hlt">frequency</span> subband compressed sensing MRI using quadruplet sampling.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sung, Kyunghyun; Hargreaves, Brian A</p> <p>2013-11-01</p> <p>To present and validate a new method that formalizes a direct <span class="hlt">link</span> between k-space and wavelet domains to apply separate undersampling and reconstruction for high- and low-spatial-<span class="hlt">frequency</span> k-space data. High- and low-spatial-<span class="hlt">frequency</span> regions are defined in k-space based on the separation of wavelet subbands, and the conventional compressed sensing problem is <span class="hlt">transformed</span> into one of localized k-space estimation. To better exploit wavelet-domain sparsity, compressed sensing can be used for high-spatial-<span class="hlt">frequency</span> regions, whereas parallel imaging can be used for low-spatial-<span class="hlt">frequency</span> regions. Fourier undersampling is also customized to better accommodate each reconstruction method: random undersampling for compressed sensing and regular undersampling for parallel imaging. Examples using the proposed method demonstrate successful reconstruction of both low-spatial-<span class="hlt">frequency</span> content and fine structures in high-resolution three-dimensional breast imaging with a net acceleration of 11-12. The proposed method improves the reconstruction accuracy of high-spatial-<span class="hlt">frequency</span> signal content and avoids incoherent artifacts in low-spatial-<span class="hlt">frequency</span> regions. This new formulation also reduces the reconstruction time due to the smaller problem size. Copyright © 2012 Wiley Periodicals, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA338885','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA338885"><span>Lightweight <span class="hlt">Transformer</span></span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1990-05-01</p> <p>could be used in any power conditioning circuit, inserted between any power source and load combination. Thus, its applicability is universal and...Typical Current Waveform from the Power Supply with a 5 ß Electrical Load -63- FILTER r—*-. REPRESENTS 16 OTOS IN PARELLEL , TEST / <span class="hlt">TRANSFORMER</span></p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Metamorphosis&pg=2&id=EJ829825','ERIC'); return false;" href="http://eric.ed.gov/?q=Metamorphosis&pg=2&id=EJ829825"><span><span class="hlt">Transformation</span> & Metamorphosis</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lott, Debra</p> <p>2009-01-01</p> <p>The sculptures of Canadian artist Brian Jungen are a great inspiration for a lesson on creating new forms. Jungen <span class="hlt">transforms</span> found objects into unique creations without fully concealing their original form or purpose. Frank Stella's sculpture series, including "K.132,2007" made of stainless steel and spray paint, is another great example of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=David+AND+Sullivan&pg=6&id=ED391233','ERIC'); return false;" href="https://eric.ed.gov/?q=David+AND+Sullivan&pg=6&id=ED391233"><span><span class="hlt">Transforming</span> Schools.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Cookson, Peter W., Jr., Ed.; Schneider, Barbara, Ed.</p> <p></p> <p>The authors in this book address the issues that relate to the crisis in American education and review some of the proposed solutions. To <span class="hlt">transform</span> education, schools must be examined as social systems that are interrelated with families, communities, and the world of work. Following the introduction, section 1, "Conditions for Educational…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Steel&pg=6&id=EJ829825','ERIC'); return false;" href="https://eric.ed.gov/?q=Steel&pg=6&id=EJ829825"><span><span class="hlt">Transformation</span> & Metamorphosis</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lott, Debra</p> <p>2009-01-01</p> <p>The sculptures of Canadian artist Brian Jungen are a great inspiration for a lesson on creating new forms. Jungen <span class="hlt">transforms</span> found objects into unique creations without fully concealing their original form or purpose. Frank Stella's sculpture series, including "K.132,2007" made of stainless steel and spray paint, is another great example of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=stuff&pg=7&id=EJ786545','ERIC'); return false;" href="https://eric.ed.gov/?q=stuff&pg=7&id=EJ786545"><span><span class="hlt">Transformation</span> Time</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Berry, John N., III</p> <p>2007-01-01</p> <p>The program for the march by librarians on America's capital for the American Library Association (ALA) conference is predictably loaded with lobbying, legislation, and DC tours. It also abounds with professional opportunity and reflects the impact of Leslie Burger, one of the most activist ALA presidents in recent history. Her "<span class="hlt">Transformation</span>"…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=invention+AND+definition&pg=4&id=ED391233','ERIC'); return false;" href="http://eric.ed.gov/?q=invention+AND+definition&pg=4&id=ED391233"><span><span class="hlt">Transforming</span> Schools.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Cookson, Peter W., Jr., Ed.; Schneider, Barbara, Ed.</p> <p></p> <p>The authors in this book address the issues that relate to the crisis in American education and review some of the proposed solutions. To <span class="hlt">transform</span> education, schools must be examined as social systems that are interrelated with families, communities, and the world of work. Following the introduction, section 1, "Conditions for Educational…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=competition+AND+expert&pg=4&id=ED509137','ERIC'); return false;" href="http://eric.ed.gov/?q=competition+AND+expert&pg=4&id=ED509137"><span><span class="hlt">Transformative</span> Assessment</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Popham, W. James</p> <p>2008-01-01</p> <p>If you're at all skeptical that "formative assessment" is just another buzzword, then here's a book that will change the way you think about the role that formative assessment can play in <span class="hlt">transforming</span> education into a more powerful and positive process. Renowned expert W. James Popham clarifies what formative assessment really is, why…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=moss&pg=7&id=EJ487821','ERIC'); return false;" href="http://eric.ed.gov/?q=moss&pg=7&id=EJ487821"><span><span class="hlt">Transforming</span> Curriculum.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Cronin, C. H.; Feldman, Phillip</p> <p>1994-01-01</p> <p>Presents comparisons between the traditional curriculum and the essential learnings curriculum implemented at the Moss Point School District in Moss Point, Mississippi. Describes in detail the curriculum <span class="hlt">transformation</span> process. Provides insight into the role of technology in the reading/language arts curriculum. (RS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=burger&id=EJ786545','ERIC'); return false;" href="http://eric.ed.gov/?q=burger&id=EJ786545"><span><span class="hlt">Transformation</span> Time</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Berry, John N., III</p> <p>2007-01-01</p> <p>The program for the march by librarians on America's capital for the American Library Association (ALA) conference is predictably loaded with lobbying, legislation, and DC tours. It also abounds with professional opportunity and reflects the impact of Leslie Burger, one of the most activist ALA presidents in recent history. Her "<span class="hlt">Transformation</span>"…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012shol.book.1285H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012shol.book.1285H"><span><span class="hlt">Frequency</span> Combs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hänsch, Theodor W.; Picqué, Nathalie</p> <p></p> <p>Much of modern research in the field of atomic, molecular, and optical science relies on lasers, which were invented some 50 years ago and perfected in five decades of intense research and development. Today, lasers and photonic technologies impact most fields of science and they have become indispensible in our daily lives. Laser <span class="hlt">frequency</span> combs were conceived a decade ago as tools for the precision spectroscopy of atomic hydrogen. Through the development of optical <span class="hlt">frequency</span> comb techniques, <Secondary>technique</Secondary> a setup of the size 1 ×1 m2, good for precision measurements of any <span class="hlt">frequency</span>, and even commercially available, has replaced the elaborate previous <span class="hlt">frequency</span>-chain schemes for optical <span class="hlt">frequency</span> measurements, which only worked for selected <span class="hlt">frequencies</span>. A true revolution in optical <span class="hlt">frequency</span> measurements has occurred, paving the way for the creation of all-optical clocks <Secondary>clock</Secondary> with a precision that might approach 10-18. A decade later, <span class="hlt">frequency</span> combs are now common equipment in all <span class="hlt">frequency</span> metrology-oriented laboratories. They are also becoming enabling tools for an increasing number of applications, from the calibration of astronomical spectrographs to molecular spectroscopy. This chapter first describes the principle of an optical <span class="hlt">frequency</span> comb synthesizer. Some of the key technologies to generate such a <span class="hlt">frequency</span> comb are then presented. Finally, a non-exhaustive overview of the growing applications is given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SJRUP..29...95V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SJRUP..29...95V"><span>Intelligent <span class="hlt">Transformer</span>: Possibilities and Challenges</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Viktor, Beldjajev; Indrek, Roasto; Tõnu, Lehtla</p> <p>2011-01-01</p> <p>This paper covers the concept of an intelligent <span class="hlt">transformer</span> that is a good candidate to replace a conventional low <span class="hlt">frequency</span> <span class="hlt">transformer</span> in the microgrids. As the power production and consumption can vary in a wide range, the new substations have to meet many requirements to guarantee reliable energy management in the autonomous networks. Different topologies of intelligent <span class="hlt">transformers</span> can be used to meet these requirements. Therefore the advantages and disadvantages of the existing topologies were analyzed. The future trends and challenges are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhyA..480...63S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhyA..480...63S"><span>κ-deformed Fourier <span class="hlt">transform</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scarfone, A. M.</p> <p>2017-08-01</p> <p>We present a new formulation of Fourier <span class="hlt">transform</span> in the picture of the κ-algebra derived in the framework of the κ-generalized statistical mechanics. The κ-Fourier <span class="hlt">transform</span> is obtained from a κ-Fourier series recently introduced by Scarfone (2013). The kernel of this <span class="hlt">transform</span>, that reduces to the usual exponential phase in the κ → 0 limit, is composed by a κ-deformed phase and a damping factor that gives a wavelet-like behaviour. We show that the κ-Fourier <span class="hlt">transform</span> is isomorph to the standard Fourier <span class="hlt">transform</span> through a changing of time and <span class="hlt">frequency</span> variables. Nevertheless, the new formalism is useful to study, according to Fourier analysis, those functions defined in the realm of the κ-algebra. As a relevant application, we discuss the central limit theorem for the κ-sum of n-iterate statistically independent random variables.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19997365','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19997365"><span><span class="hlt">Frequency</span> comb swept lasers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tsai, Tsung-Han; Zhou, Chao; Adler, Desmond C; Fujimoto, James G</p> <p>2009-11-09</p> <p>We demonstrate a <span class="hlt">frequency</span> comb (FC) swept laser and a <span class="hlt">frequency</span> comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep rate of 1kHz and 120kHz, respectively over a 135nm tuning range centered at 1310nm with average output powers of 50mW. A 25GHz free spectral range <span class="hlt">frequency</span> comb filter in the swept lasers causes the lasers to generate a series of well defined <span class="hlt">frequency</span> steps. The narrow bandwidth (0.015nm) of the <span class="hlt">frequency</span> comb filter enables a approximately -1.2dB sensitivity roll off over approximately 3mm range, compared to conventional swept source and FDML lasers which have -10dB and -5dB roll offs, respectively. Measurements at very long ranges are possible with minimal sensitivity loss, however reflections from outside the principal measurement range of 0-3mm appear aliased back into the principal range. In addition, the <span class="hlt">frequency</span> comb output from the lasers are equally spaced in <span class="hlt">frequency</span> (linear in k-space). The filtered laser output can be used to self-clock the OCT interference signal sampling, enabling direct fast Fourier <span class="hlt">transformation</span> of the fringe signals, without the need for fringe recalibration procedures. The design and operation principles of FC swept lasers are discussed and designs for short cavity lasers for OCT and interferometric measurement applications are proposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2890237','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2890237"><span><span class="hlt">Frequency</span> comb swept lasers</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tsai, Tsung-Han; Zhou, Chao; Adler, Desmond C.; Fujimoto, James G.</p> <p>2010-01-01</p> <p>We demonstrate a <span class="hlt">frequency</span> comb (FC) swept laser and a <span class="hlt">frequency</span> comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep rate of 1kHz and 120kHz, respectively over a 135nm tuning range centered at 1310nm with average output powers of 50mW. A 25GHz free spectral range <span class="hlt">frequency</span> comb filter in the swept lasers causes the lasers to generate a series of well defined <span class="hlt">frequency</span> steps. The narrow bandwidth (0.015nm) of the <span class="hlt">frequency</span> comb filter enables a ~−1.2dB sensitivity roll off over ~3mm range, compared to conventional swept source and FDML lasers which have −10dB and −5dB roll offs, respectively. Measurements at very long ranges are possible with minimal sensitivity loss, however reflections from outside the principal measurement range of 0–3mm appear aliased back into the principal range. In addition, the <span class="hlt">frequency</span> comb output from the lasers are equally spaced in <span class="hlt">frequency</span> (linear in k-space). The filtered laser output can be used to self-clock the OCT interference signal sampling, enabling direct fast Fourier <span class="hlt">transformation</span> of the fringe signals, without the need for fringe recalibration procedures. The design and operation principles of FC swept lasers are discussed and designs for short cavity lasers for OCT and interferometric measurement applications are proposed. PMID:19997365</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MSSP...95..488L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MSSP...95..488L"><span>Use of the Morlet mother wavelet in the <span class="hlt">frequency</span>-scale domain decomposition technique for the modal identification of ambient vibration responses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Le, Thien-Phu</p> <p>2017-10-01</p> <p>The <span class="hlt">frequency</span>-scale domain decomposition technique has recently been proposed for operational modal analysis. The technique is based on the Cauchy mother wavelet. In this paper, the approach is extended to the Morlet mother wavelet, which is very popular in signal processing due to its superior time-<span class="hlt">frequency</span> localization. Based on the regressive form and an appropriate norm of the Morlet mother wavelet, the continuous wavelet <span class="hlt">transform</span> of the power spectral density of ambient responses enables modes in the <span class="hlt">frequency</span>-scale domain to be highlighted. Analytical developments first demonstrate the <span class="hlt">link</span> between modal parameters and the local maxima of the continuous wavelet <span class="hlt">transform</span> modulus. The <span class="hlt">link</span> formula is then used as the foundation of the proposed modal identification method. Its practical procedure, combined with the singular value decomposition algorithm, is presented step by step. The proposition is finally verified using numerical examples and a laboratory test.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21659598','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21659598"><span><span class="hlt">Transformation</span> optics using graphene.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vakil, Ashkan; Engheta, Nader</p> <p>2011-06-10</p> <p>Metamaterials and <span class="hlt">transformation</span> optics play substantial roles in various branches of optical science and engineering by providing schemes to tailor electromagnetic fields into desired spatial patterns. We report a theoretical study showing that by designing and manipulating spatially inhomogeneous, nonuniform conductivity patterns across a flake of graphene, one can have this material as a one-atom-thick platform for infrared metamaterials and <span class="hlt">transformation</span> optical devices. Varying the graphene chemical potential by using static electric field yields a way to tune the graphene conductivity in the terahertz and infrared <span class="hlt">frequencies</span>. Such degree of freedom provides the prospect of having different "patches" with different conductivities on a single flake of graphene. Numerous photonic functions and metamaterial concepts can be expected to follow from such a platform.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/863451','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/863451"><span>RF <span class="hlt">transformer</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Smith, James L.; Helenberg, Harold W.; Kilsdonk, Dennis J.</p> <p>1979-01-01</p> <p>There is provided an improved RF <span class="hlt">transformer</span> having a single-turn secondary of cylindrical shape and a coiled encapsulated primary contained within the secondary. The coil is tapered so that the narrowest separation between the primary and the secondary is at one end of the coil. The encapsulated primary is removable from the secondary so that a variety of different capacity primaries can be utilized with one secondary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988EOSTr..69..620.','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988EOSTr..69..620."><span>Transatlantic <span class="hlt">link</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p></p> <p></p> <p>(left) European Geophysical Society (EGS) President Rolf Meissner at AGU Headquarters with (center) Executive Director Fred Spilhaus and (right) Foreign Secretary Juan Roederer. Meissner attended the meeting of AGU's Committee on International Participation (CIP) on February 26, 1988. At that meeting, specific ways of fostering close <span class="hlt">links</span> between AGU and EGS were discussed.A few weeks later, Roederer and AGU staff, working with EGS Secretary-General Arne Richter at the EGS meeting in Bologna, Italy, March 21-25, planned details of the establishment of an AGU office in Europe. The Copernicus Gesellschaft, a new entity located on the premises of the Max Planck Institute for Aeronomy in Lindau, Federal Republic of Germany, will provide the administrative staff and handle logistics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=277048','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=277048"><span><span class="hlt">TRANSFORMATION</span> OF BACILLUS LICHENIFORMIS1</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gwinn, Darrel D.; Thorne, Curtis B.</p> <p>1964-01-01</p> <p>Gwinn, Darrel D. (Oregon State University, Corvallis), and Curtis B. Thorne. <span class="hlt">Transformation</span> of Bacillus licheniformis. J. Bacteriol. 87:519–526. 1964.—When a series of 28 auxotrophic mutants of Bacillus licheniformis were screened for <span class="hlt">transformation</span>, only three of them, M28 (glycine−), M30 (uncharacterized), and M33 (purine−), produced a detectable number of <span class="hlt">transformants</span>. The screening method consisted of spreading auxotrophic cells and deoxyribonucleic acid (DNA) from the prototrophic strain 9945A on minimal agar plates and observing the plates for development of prototrophic colonies. M28 <span class="hlt">transformed</span> at a higher <span class="hlt">frequency</span> than did the two other mutants, and it was studied in greater detail. Although up to 20% of the recipient cells spread on the plates in the presence of DNA gave rise to prototrophic colonies over a period of 72 hr, only about 10−3% of the cells produced <span class="hlt">transformants</span> when they were incubated with DNA in liquid suspension for 1 hr. The most competent cultures of many tested were those grown on a shaker for 22 hr in a medium composed of nutrient broth, salts, and glycerol. When mutations resulting in requirements for histidine, leucine, serine, and trytophan were introduced singly into the glycine mutant, <span class="hlt">transformants</span> for the leucine, serine, and histidine markers could be obtained at will, but <span class="hlt">transformants</span> for the tryptophan marker were not detected even though all four of the double mutants could be <span class="hlt">transformed</span> to glycine independence. PMID:14127566</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860012072','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860012072"><span>High <span class="hlt">frequency</span>-heated air turbojet</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miron, J. H. D.</p> <p>1986-01-01</p> <p>A description is given of a method to heat air coming from a turbojet compressor to a temperature necessary to produce required expansion without requiring fuel. This is done by high <span class="hlt">frequency</span> heating, which heats the walls corresponding to the combustion chamber in existing jets, by mounting high <span class="hlt">frequency</span> coils in them. The current <span class="hlt">transformer</span> and high <span class="hlt">frequency</span> generator to be used are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20705422','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20705422"><span>Hough <span class="hlt">transform</span> search for continuous gravitational waves</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Krishnan, Badri; Papa, Maria Alessandra; Sintes, Alicia M.; Schutz, Bernard F.; Frasca, Sergio; Palomba, Cristiano</p> <p>2004-10-15</p> <p>This paper describes an incoherent method to search for continuous gravitational waves based on the Hough <span class="hlt">transform</span>, a well-known technique used for detecting patterns in digital images. We apply the Hough <span class="hlt">transform</span> to detect patterns in the time-<span class="hlt">frequency</span> plane of the data produced by an earth-based gravitational wave detector. Two different flavors of searches will be considered, depending on the type of input to the Hough <span class="hlt">transform</span>: either Fourier <span class="hlt">transforms</span> of the detector data or the output of a coherent matched-filtering type search. We present the technical details for implementing the Hough <span class="hlt">transform</span> algorithm for both kinds of searches, their statistical properties, and their sensitivities.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997AAS...191.3501U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997AAS...191.3501U"><span>Hamlet's <span class="hlt">Transformation</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Usher, P. D.</p> <p>1997-12-01</p> <p>William Shakespeare's Hamlet has much evidence to suggest that the Bard was aware of the cosmological models of his time, specifically the geocentric bounded Ptolemaic and Tychonic models, and the infinite Diggesian. Moreover, Shakespeare describes how the Ptolemaic model is to be <span class="hlt">transformed</span> to the Diggesian. Hamlet's "<span class="hlt">transformation</span>" is the reason that Claudius, who personifies the Ptolemaic model, summons Rosencrantz and Guildenstern, who personify the Tychonic. Pantometria, written by Leonard Digges and his son Thomas in 1571, contains the first technical use of the word "<span class="hlt">transformation</span>." At age thirty, Thomas Digges went on to propose his Perfit Description, as alluded to in Act Five where Hamlet's age is given as thirty. In Act Five as well, the words "bore" and "arms" refer to Thomas' vocation as muster-master and his scientific interest in ballistics. England's leading astronomer was also the father of the poet whose encomium introduced the First Folio of 1623. His oldest child Dudley became a member of the Virginia Company and facilitated the writing of The Tempest. Taken as a whole, such manifold connections to Thomas Digges support Hotson's contention that Shakespeare knew the Digges family. Rosencrantz and Guildenstern in Hamlet bear Danish names because they personify the Danish model, while the king's name is latinized like that of Claudius Ptolemaeus. The reason Shakespeare anglicized "Amleth" to "Hamlet" was because he saw a parallel between Book Three of Saxo Grammaticus and the eventual triumph of the Diggesian model. But Shakespeare eschewed Book Four, creating this particular ending from an infinity of other possibilities because it "suited his purpose," viz. to celebrate the concept of a boundless universe of stars like the Sun.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4762553','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4762553"><span><span class="hlt">TRANSFORMER</span> APPARATUS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Wolfgang, F.; Nicol, J.</p> <p>1962-11-01</p> <p><span class="hlt">Transformer</span> apparatus is designed for measuring the amount of a paramagnetic substance dissolved or suspended in a diamagnetic liquid. The apparatus consists of a cluster of tubes, some of which are closed and have sealed within the diamagnetic substance without any of the paramagnetic material. The remaining tubes are open to flow of the mix- ture. Primary and secondary conductors are wrapped around the tubes in such a way as to cancel noise components and also to produce a differential signal on the secondaries based upon variations of the content of the paramagnetic material. (AEC)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060036606&hterms=transformer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dtransformer','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060036606&hterms=transformer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dtransformer"><span>Rotary <span class="hlt">Transformer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McLyman, Colonel Wm. T.</p> <p>1996-01-01</p> <p>None given. From first Par: Many spacecraft (S/C) and surface rovers require the transfer of signals and power across rotating interfaces. Science instruments, antennas and solar arrays are elements needing rotary power transfer for certain (S/C) configurations. Delivery of signal and power has mainly been done by using the simplest means, the slip ring approach. This approach, although simple, leaves debris generating noise over a period of time...The rotary <span class="hlt">transformer</span> is a good alternative to slip rings for signal and power transfer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JARS...10b5023J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JARS...10b5023J"><span>Remote sensing image fusion method in CIELab color space using nonsubsampled shearlet <span class="hlt">transform</span> and pulse coupled neural networks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jin, Xin; Zhou, Dongming; Yao, Shaowen; Nie, Rencan; Yu, Chuanbo; Ding, Tingting</p> <p>2016-04-01</p> <p>In CIELab color space, we propose a remote sensing image fusion technique based on nonsubsampled shearlet <span class="hlt">transform</span> (NSST) and pulse coupled neural network (PCNN), which aim to improve the efficiency and performance of the remote sensing image fusion by combining the excellent properties of the two methods. First, panchromatic (PAN) and multispectral (MS) are <span class="hlt">transformed</span> into CIELab color space to get different color components. Second, PAN and L component of MS are decomposed by the NSST to obtain corresponding the low-<span class="hlt">frequency</span> coefficients and high-<span class="hlt">frequency</span> coefficients. Third, the low-<span class="hlt">frequency</span> coefficients are fused by intersecting cortical model (ICM); the high-<span class="hlt">frequency</span> coefficients are divided into several sub-blocks to calculate the average gradient (AG), and the <span class="hlt">linking</span> strength β of PCNN model is determined by the AG, so that the parameters β can be adaptively set according to the quality of the sub-block images, then the sub-blocks image are input into PCNN to get the oscillation <span class="hlt">frequency</span> graph (OFG), the method can get the fused high-<span class="hlt">frequency</span> coefficients according to the OFG. Finally, the fused L component is obtained by inverse NSST, and the fused RGB color image is obtained through inverse CIELab <span class="hlt">transform</span>. The experimental results demonstrate that the proposed method provide better effect compared with other common methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA495512','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA495512"><span>A Short-Segment Fourier <span class="hlt">Transform</span> Methodology</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2009-03-01</p> <p>defined sampling of the continuous-valued discrete-time Fourier <span class="hlt">transform</span>, superresolution in the <span class="hlt">frequency</span> domain and allowance of Dirac delta functions associated with pure sinusoidal input data components.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005IJTPE.125..759F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005IJTPE.125..759F"><span>A Transfer Voltage Simulation Method for Generator Step Up <span class="hlt">Transformers</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Funabashi, Toshihisa; Sugimoto, Toshirou; Ueda, Toshiaki; Ametani, Akihiro</p> <p></p> <p>It has been found from measurements for 13 sets of GSU <span class="hlt">transformers</span> that a transfer voltage of a generator step-up (GSU) <span class="hlt">transformer</span> involves one dominant oscillation <span class="hlt">frequency</span>. The <span class="hlt">frequency</span> can be estimated from the inductance and capacitance values of the GSU <span class="hlt">transformer</span> low-voltage-side. This observation has led to a new method for simulating a GSU <span class="hlt">transformer</span> transfer voltage. The method is based on the EMTP <span class="hlt">TRANSFORMER</span> model, but stray capacitances are added. The leakage inductance and the magnetizing resistance are modified using approximate curves for their <span class="hlt">frequency</span> characteristics determined from the measured results. The new method is validated in comparison with the measured results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997SPIE.3068..124M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997SPIE.3068..124M"><span>Wavelet <span class="hlt">transform</span> application in human face recognition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meng, Qiang; Thompson, Wiley E.; Flachs, Gerald M.; Jordan, Jay B.</p> <p>1997-07-01</p> <p>A wavelet <span class="hlt">transformation</span> is introduced as a new method to extract sideview face features in human face recognition. Utilizing the wavelet <span class="hlt">transformation</span>, a sideview profile is decomposed as high <span class="hlt">frequency</span> and low <span class="hlt">frequency</span> components. Signal reconstruction, autocorrelation and energy distribution are used to decide a optimal decomposition level in the wavelet <span class="hlt">transformation</span> without losing sideview features. To evaluate the feasibility of the wavelet <span class="hlt">transformation</span> features in human sideview face recognition, the tie statistic is used to compute the complexity of the wavelet <span class="hlt">transform</span> features. Using wavelet <span class="hlt">transformation</span>, the sideview data size is reduced. The reduced features have almost the same ability as the original sideview face profile data in terms of distinguishing different people. The computational expense is greatly decreased. The results of the experiments are also shown in this paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4918344','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4918344"><span>High spectral purity Kerr <span class="hlt">frequency</span> comb radio <span class="hlt">frequency</span> photonic oscillator</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Liang, W.; Eliyahu, D.; Ilchenko, V. S.; Savchenkov, A. A.; Matsko, A. B.; Seidel, D.; Maleki, L.</p> <p>2015-01-01</p> <p>Femtosecond laser-based generation of radio <span class="hlt">frequency</span> signals has produced astonishing improvements in achievable spectral purity, one of the basic features characterizing the performance of an radio <span class="hlt">frequency</span> oscillator. Kerr <span class="hlt">frequency</span> combs hold promise for <span class="hlt">transforming</span> these lab-scale oscillators to chip-scale level. In this work we demonstrate a miniature 10 GHz radio <span class="hlt">frequency</span> photonic oscillator characterized with phase noise better than −60 dBc Hz−1 at 10 Hz, −90 dBc Hz−1 at 100 Hz and −170 dBc Hz−1 at 10 MHz. The <span class="hlt">frequency</span> stability of this device, as represented by Allan deviation measurements, is at the level of 10−10 at 1–100 s integration time—orders of magnitude better than existing radio <span class="hlt">frequency</span> photonic devices of similar size, weight and power consumption. PMID:26260955</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26260955','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26260955"><span>High spectral purity Kerr <span class="hlt">frequency</span> comb radio <span class="hlt">frequency</span> photonic oscillator.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liang, W; Eliyahu, D; Ilchenko, V S; Savchenkov, A A; Matsko, A B; Seidel, D; Maleki, L</p> <p>2015-08-11</p> <p>Femtosecond laser-based generation of radio <span class="hlt">frequency</span> signals has produced astonishing improvements in achievable spectral purity, one of the basic features characterizing the performance of an radio <span class="hlt">frequency</span> oscillator. Kerr <span class="hlt">frequency</span> combs hold promise for <span class="hlt">transforming</span> these lab-scale oscillators to chip-scale level. In this work we demonstrate a miniature 10 GHz radio <span class="hlt">frequency</span> photonic oscillator characterized with phase noise better than -60 dBc Hz(-1) at 10 Hz, -90 dBc Hz(-1) at 100 Hz and -170 dBc Hz(-1) at 10 MHz. The <span class="hlt">frequency</span> stability of this device, as represented by Allan deviation measurements, is at the level of 10(-10) at 1-100 s integration time-orders of magnitude better than existing radio <span class="hlt">frequency</span> photonic devices of similar size, weight and power consumption.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2575124','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2575124"><span>Prior Knowledge and Exemplar <span class="hlt">Frequency</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Harris, Harlan D.; Murphy, Gregory L.; Rehder, Bob</p> <p>2008-01-01</p> <p>New concepts can be learned by statistical associations as well as by relevant existing knowledge. We examined the interaction of these two processes by manipulating exemplar <span class="hlt">frequency</span> and thematic knowledge and considering their interaction through computational modeling. Exemplar <span class="hlt">frequency</span> affects category learning, with high <span class="hlt">frequency</span> items learned faster than low <span class="hlt">frequency</span> items, and prior knowledge usually speeds category learning. In two experiments that manipulated both of these factors, we found that the effects of <span class="hlt">frequency</span> are greatly reduced when stimulus features are <span class="hlt">linked</span> by thematic prior knowledge, and that <span class="hlt">frequency</span> effects on single stimulus features can actually be reversed by knowledge. We account for these results with the Knowledge Resonance (KRES) model of category learning (Rehder & Murphy, 2003) and conclude that prior knowledge may change representations so that empirical effects such as those caused by <span class="hlt">frequency</span> manipulations are modulated. PMID:18927047</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA411450','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA411450"><span>EEG Multiresolution Analysis Using Wavelet <span class="hlt">Transform</span></span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2007-11-02</p> <p>Wavelet <span class="hlt">transform</span> (WT) is a new multiresolution time-<span class="hlt">frequency</span> analysis method. WT possesses well localization feature both in tine and <span class="hlt">frequency</span>...plays a key role in the diagnosing diseases and is useful for both physiological research and medical applications. Using the dyadic wavelet ... <span class="hlt">transform</span> the EEG signals are successfully decomposed to the alpha rhythm (8-13Hz) beta rhythm (14-30Hz) theta rhythm (4-7Hz) and delta rhythm (0.3-3Hz) and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4349091','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4349091"><span>The Evolving Puzzle of Autosomal Versus Y-<span class="hlt">linked</span> Male Determination in Musca domestica</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hamm, Ronda L.; Meisel, Richard P.; Scott, Jeffrey G.</p> <p>2014-01-01</p> <p>Sex determination is one of the most rapidly evolving developmental pathways, but the factors responsible for this fast evolution are not well resolved. The house fly, Musca domestica, is an ideal model for studying sex determination because house fly sex determination is polygenic and varies considerably between populations. Male house flies possess a male-determining locus, the M factor, which can be located on the Y or X chromosome or any of the five autosomes. There can be a single M or multiple M factors present in an individual male, in heterozygous or homozygous condition. Males with multiple copies of M skew the sex ratio toward the production of males. Potentially in response to these male-biased sex ratios, an allele of the gene <span class="hlt">transformer</span>, Md-traD, promotes female development in the presence of one or multiple M factors. There have been many studies to determine the linkage and <span class="hlt">frequency</span> of these male determining factors and the <span class="hlt">frequency</span> of Md-traD chromosomes in populations from around the world. This review provides a summary of the information available to date regarding the patterns of distribution of autosomal, X-<span class="hlt">linked</span> and Y-<span class="hlt">linked</span> M factors, the relative <span class="hlt">frequencies</span> of the linkage of M, the changes in <span class="hlt">frequencies</span> found in field populations, and the fitness of males with autosomal M factors vs. Y-<span class="hlt">linked</span> M. We evaluate this natural variation in the house fly sex determination pathway in light of models of the evolution of sex determination. PMID:25552607</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940006184','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940006184"><span>Subband/<span class="hlt">transform</span> functions for image processing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Glover, Daniel</p> <p>1993-01-01</p> <p>Functions for image data processing written for use with the MATLAB(TM) software package are presented. These functions provide the capability to <span class="hlt">transform</span> image data with block <span class="hlt">transformations</span> (such as the Walsh Hadamard) and to produce spatial <span class="hlt">frequency</span> subbands of the <span class="hlt">transformed</span> data. Block <span class="hlt">transforms</span> are equivalent to simple subband systems. The <span class="hlt">transform</span> coefficients are reordered using a simple permutation to give subbands. The low <span class="hlt">frequency</span> subband is a low resolution version of the original image, while the higher <span class="hlt">frequency</span> subbands contain edge information. The <span class="hlt">transform</span> functions can be cascaded to provide further decomposition into more subbands. If the cascade is applied to all four of the first stage subbands (in the case of a four band decomposition), then a uniform structure of sixteen bands is obtained. If the cascade is applied only to the low <span class="hlt">frequency</span> subband, an octave structure of seven bands results. Functions for the inverse <span class="hlt">transforms</span> are also given. These functions can be used for image data compression systems. The <span class="hlt">transforms</span> do not in themselves produce data compression, but prepare the data for quantization and compression. Sample quantization functions for subbands are also given. A typical compression approach is to subband the image data, quantize it, then use statistical coding (e.g., run-length coding followed by Huffman coding) for compression. Contour plots of image data and subbanded data are shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6181644','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6181644"><span><span class="hlt">Transformation</span> of human cells by DNAs ineffective in <span class="hlt">transformation</span> of NIH 3T3 cells</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sutherland, B.M.; Bennett, P.B.; Freeman, A.G.; Moore, S.P.; Strickland, P.T.</p> <p>1985-04-01</p> <p>Neonatal human foreskin fibroblasts can be <span class="hlt">transformed</span> to anchorage-independent growth by transfection with DNAs inefficient in <span class="hlt">transforming</span> NIH 3T3 cells. Human cells transfected with DNA from GM 1312, a multiple myeloma cell line, or MOLT-4, a permanent lymphoblast line, grow without anchorage at a much higher <span class="hlt">frequency</span> than do the parental cells and their DNAs can <span class="hlt">transform</span> human cell recipients to anchorage-independent growth; they have extended but not indefinite life spans and are nontumorigenic. Human fibroblasts are also <span class="hlt">transformed</span> by DNAs from two multiple myeloma lines that also <span class="hlt">transform</span> 3T3 cells; however, restriction analysis suggests that different <span class="hlt">transforming</span> genes in this DNA are acting in the human and murine systems. These results indicate that the human cell transfection system allows detection of <span class="hlt">transforming</span> genes not effective in the 3T3 system and points out the possibility of detection of additional <span class="hlt">transforming</span> sequences even in DNAs that do <span class="hlt">transform</span> murine cells.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1338748','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1338748"><span>Phase <span class="hlt">Transformations</span> and Microstructural Evolution: Part II</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Clarke, Amy Jean</p> <p>2015-10-30</p> <p>The activities of the Phase <span class="hlt">Transformations</span> Committee of the Materials Processing & Manufacturing Division (MPMD) of The Minerals, Metals & Materials Society (TMS) are oriented toward understanding the fundamental aspects of phase <span class="hlt">transformations</span>. Emphasis is placed on the thermodynamic driving forces for phase <span class="hlt">transformations</span>, the kinetics of nucleation and growth, interfacial structures and energies, <span class="hlt">transformation</span> crystallography, surface reliefs, and, above all, the atomic mechanisms of phase <span class="hlt">transformations</span>. Phase <span class="hlt">transformations</span> and microstructural evolution are directly <span class="hlt">linked</span> to materials processing, properties, and performance. In this issue, aspects of liquid–solid and solid-state phase <span class="hlt">transformations</span> and microstructural evolution are highlighted. Many papers in this issue are highlighted by this paper, giving a brief summary of what they bring to the scientific community.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1338747','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1338747"><span>Phase <span class="hlt">Transformations</span> and Microstructural Evolution: Part I</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Clarke, Amy Jean</p> <p>2015-08-29</p> <p>The activities of the Phase <span class="hlt">Transformations</span> Committee of the Materials Processing & Manufacturing Division (MPMD) of The Minerals, Metals & Materials Society (TMS) are oriented toward understanding the fundamental aspects of phase <span class="hlt">transformations</span>. Emphasis is placed on the thermodynamic driving forces for phase <span class="hlt">transformations</span>, the kinetics of nucleation and growth, interfacial structures and energies, <span class="hlt">transformation</span> crystallography, surface reliefs, and, above all, the atomic mechanisms of phase <span class="hlt">transformations</span>. Phase <span class="hlt">transformations</span> and microstructural evolution are directly <span class="hlt">linked</span> to materials processing, properties, and performance, including in extreme environments, of structural metal alloys. In this paper, aspects of phase <span class="hlt">transformations</span> and microstructural evolution are highlighted from the atomic to the microscopic scale for ferrous and non-ferrous alloys. Many papers from this issue are highlighted with small summaries of their scientific achievements given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1338748-phase-transformations-microstructural-evolution-part-ii','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1338748-phase-transformations-microstructural-evolution-part-ii"><span>Phase <span class="hlt">Transformations</span> and Microstructural Evolution: Part II</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Clarke, Amy Jean</p> <p>2015-10-30</p> <p>The activities of the Phase <span class="hlt">Transformations</span> Committee of the Materials Processing & Manufacturing Division (MPMD) of The Minerals, Metals & Materials Society (TMS) are oriented toward understanding the fundamental aspects of phase <span class="hlt">transformations</span>. Emphasis is placed on the thermodynamic driving forces for phase <span class="hlt">transformations</span>, the kinetics of nucleation and growth, interfacial structures and energies, <span class="hlt">transformation</span> crystallography, surface reliefs, and, above all, the atomic mechanisms of phase <span class="hlt">transformations</span>. Phase <span class="hlt">transformations</span> and microstructural evolution are directly <span class="hlt">linked</span> to materials processing, properties, and performance. In this issue, aspects of liquid–solid and solid-state phase <span class="hlt">transformations</span> and microstructural evolution are highlighted. Many papers in thismore » issue are highlighted by this paper, giving a brief summary of what they bring to the scientific community.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1338747-phase-transformations-microstructural-evolution-part','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1338747-phase-transformations-microstructural-evolution-part"><span>Phase <span class="hlt">Transformations</span> and Microstructural Evolution: Part I</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Clarke, Amy Jean</p> <p>2015-08-29</p> <p>The activities of the Phase <span class="hlt">Transformations</span> Committee of the Materials Processing & Manufacturing Division (MPMD) of The Minerals, Metals & Materials Society (TMS) are oriented toward understanding the fundamental aspects of phase <span class="hlt">transformations</span>. Emphasis is placed on the thermodynamic driving forces for phase <span class="hlt">transformations</span>, the kinetics of nucleation and growth, interfacial structures and energies, <span class="hlt">transformation</span> crystallography, surface reliefs, and, above all, the atomic mechanisms of phase <span class="hlt">transformations</span>. Phase <span class="hlt">transformations</span> and microstructural evolution are directly <span class="hlt">linked</span> to materials processing, properties, and performance, including in extreme environments, of structural metal alloys. In this paper, aspects of phase <span class="hlt">transformations</span> and microstructural evolution aremore » highlighted from the atomic to the microscopic scale for ferrous and non-ferrous alloys. Many papers from this issue are highlighted with small summaries of their scientific achievements given.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003SPIE.5150.1912H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003SPIE.5150.1912H"><span>Slant <span class="hlt">transform</span> watermarking for digital images</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ho, Anthony T. S.; Zhu, Xunzhan; Shen, Jun</p> <p>2003-06-01</p> <p>In this paper, we propose a digital watermarking algorithm based on the Slant <span class="hlt">transform</span> for the copyright protection of images. Our earlier research work associated with the fast Hadamard <span class="hlt">transform</span> for robust watermark embedding and retrieval of images and characters suggests that this <span class="hlt">transform</span> could also provide a good "hidden" space for digital watermarking. The Slant <span class="hlt">transform</span> has many similar properties to the Walsh-Hadamard <span class="hlt">transform</span>. In terms of <span class="hlt">transform</span> coding, the Slant <span class="hlt">transform</span> is considered to be a sub-optimum orthogonal <span class="hlt">transform</span> for energy compaction. For digital watermarking, the energy spread becomes a significant advantage, as there is now a good spread of middle to higher <span class="hlt">frequencies</span> with significant energies for robust information hiding. In this paper, an analytical comparative study on the performance of the Slant <span class="hlt">transform</span> adapting our earlier watermarking schemes for fast Hadamrd <span class="hlt">transform</span> will be performed based on its robustness against various Stirmark attacks. The performance results of the Slant <span class="hlt">transform</span> for image watermarking against other <span class="hlt">transforms</span> such as Cosine <span class="hlt">transform</span> will also be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25786775','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25786775"><span>Radio <span class="hlt">frequency</span> identification-enabled capabilities in a healthcare context: An exploratory study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hornyak, Rob; Lewis, Mark; Sankaranarayan, Balaji</p> <p>2016-09-01</p> <p>Increasingly, the adoption and use of radio <span class="hlt">frequency</span> identification systems in hospital settings is gaining prominence. However, despite the <span class="hlt">transformative</span> impact that radio <span class="hlt">frequency</span> identification has in healthcare settings, few studies have examined how and why this change may occur. The purpose of this study is to systematically understand how radio <span class="hlt">frequency</span> identification can <span class="hlt">transform</span> work practices in an operational process that directly impacts cost and operational efficiency and indirectly contributes to impacting patient safety and quality of care. We leverage an interdisciplinary framework to explore the contextual characteristics that shape the assimilation of radio <span class="hlt">frequency</span> identification in healthcare settings. By <span class="hlt">linking</span> the use of radio <span class="hlt">frequency</span> identification with specific contextual dimensions in healthcare settings, we provide a data-driven account of how and why radio <span class="hlt">frequency</span> identification can be useful in inventory management in this setting. In doing so, we also contribute to recent work by information systems scholars who argue for a reconfiguration of conventional assumptions regarding the role of technology in contemporary organizations. © The Author(s) 2015.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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