Science.gov

Sample records for frequency separation variations

  1. Solar-cycle variations of large frequency separations of acoustic modes: implications for asteroseismology

    NASA Astrophysics Data System (ADS)

    Broomhall, A.-M.; Chaplin, W. J.; Elsworth, Y.; New, R.

    2011-06-01

    We have studied solar-cycle changes in the large frequency separations that can be observed in Birmingham Solar Oscillations Network (BiSON) data. The large frequency separation is often one of the first outputs from asteroseismic studies because it can help constrain stellar properties like mass and radius. We have used three methods for estimating the large separations: use of individual p-mode frequencies, computation of the autocorrelation of frequency-power spectra, and computation of the power spectrum of the power spectrum. The values of the large separations obtained by the different methods are offset from each other and have differing sensitivities to the realization noise. A simple model was used to predict solar-cycle variations in the large separations, indicating that the variations are due to the well-known solar-cycle changes to mode frequency. However, this model is only valid over a restricted frequency range. We discuss the implications of these results for asteroseismology.

  2. Radio Frequency Fragment Separator at NSCL

    NASA Astrophysics Data System (ADS)

    Bazin, D.; Andreev, V.; Becerril, A.; Doléans, M.; Mantica, P. F.; Ottarson, J.; Schatz, H.; Stoker, J. B.; Vincent, J.

    2009-07-01

    A new device has been designed and built at NSCL which provides additional filtering of radioactive beams produced via projectile fragmentation. The Radio Frequency Fragment Separator (RFFS) uses the time micro structure of the beams accelerated by the cyclotrons to deflect particles according to their time-of-flight, in effect producing a phase filtering. The transverse RF (Radio Frequency) electric field of the RFFS has superior filtering performance compared to other electrostatic devices, such as Wien filters. Such filtering is critical for radioactive beams produced on the neutron-deficient side of the valley of stability, where strong contamination occurs at intermediate energies from 50 to 200 MeV/u.

  3. 47 CFR 76.612 - Cable television frequency separation standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Cable television frequency separation standards... frequency separation standards. All cable television systems which operate in the frequency bands 108-137 and 225-400 MHz shall comply with the following frequency separation standards: (a) In...

  4. 47 CFR 76.612 - Cable television frequency separation standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Cable television frequency separation standards... frequency separation standards. All cable television systems which operate in the frequency bands 108-137 and 225-400 MHz shall comply with the following frequency separation standards: (a) In...

  5. 47 CFR 76.612 - Cable television frequency separation standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Cable television frequency separation standards... frequency separation standards. All cable television systems which operate in the frequency bands 108-137 and 225-400 MHz shall comply with the following frequency separation standards: (a) In...

  6. 47 CFR 76.612 - Cable television frequency separation standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Cable television frequency separation standards... frequency separation standards. All cable television systems which operate in the frequency bands 108-137 and 225-400 MHz shall comply with the following frequency separation standards: (a) In...

  7. 47 CFR 76.612 - Cable television frequency separation standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Cable television frequency separation standards... frequency separation standards. All cable television systems which operate in the frequency bands 108-137 and 225-400 MHz shall comply with the following frequency separation standards: (a) In...

  8. Seasonal variations of volcanic eruption frequencies

    NASA Technical Reports Server (NTRS)

    Stothers, Richard B.

    1989-01-01

    Do volcanic eruptions have a tendency to occur more frequently in the months of May and June? Some past evidence suggests that they do. The present study, based on the new eruption catalog of Simkin et al.(1981), investigates the monthly statistics of the largest eruptions, grouped according to explosive magnitude, geographical latitude, and year. At the 2-delta level, no month-to-month variations in eruption frequency are found to be statistically significant. Examination of previously published month-to-month variations suggests that they, too, are not statistically significant. It is concluded that volcanism, at least averaged over large portions of the globe, is probably not periodic on a seasonal or annual time scale.

  9. Advances in high frequency ultrasound separation of particulates from biomass.

    PubMed

    Juliano, Pablo; Augustin, Mary Ann; Xu, Xin-Qing; Mawson, Raymond; Knoerzer, Kai

    2017-03-01

    In recent years the use of high frequency ultrasound standing waves (megasonics) for droplet or cell separation from biomass has emerged beyond the microfluidics scale into the litre to industrial scale applications. The principle for this separation technology relies on the differential positioning of individual droplets or particles across an ultrasonic standing wave field within the reactor and subsequent biomass material predisposition for separation via rapid droplet agglomeration or coalescence into larger entities. Large scale transducers have been characterised with sonochemiluminescence and hydrophones to enable better reactor designs. High frequency enhanced separation technology has been demonstrated at industrial scale for oil recovery in the palm oil industry and at litre scale to assist olive oil, coconut oil and milk fat separation. Other applications include algal cell dewatering and milk fat globule fractionation. Frequency selection depends on the material properties and structure in the biomass mixture. Higher frequencies (1 and 2MHz) have proven preferable for better separation of materials with smaller sized droplets such as milk fat globules. For palm oil and olive oil, separation has been demonstrated within the 400-600kHz region, which has high radical production, without detectable impact on product quality.

  10. 46 CFR 111.01-17 - Voltage and frequency variations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Voltage and frequency variations. 111.01-17 Section 111... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General § 111.01-17 Voltage and frequency variations. Unless otherwise stated, electrical equipment must function at variations of at least ±5 percent of rated...

  11. Variations of the Milankovitch frequencies in time

    NASA Technical Reports Server (NTRS)

    Loutre, Marie-France; Berger, A.

    1992-01-01

    The sensitivity of the amplitudes and frequencies in the development of the Earth's orbital and rotational elements involved in the astronomical theory of paleoclimates (eccentricity, obliquity, and climate precession), to the Earth-Moon distance and consequently to the length of the day and to the dynamical ellipticity of the Earth has been discussed for the last billions of years. The shortening of the Earth-Moon distance and of the length of the day, as well as the lengthening of the dynamical ellipticity of the Earth back in time induce a shortening of the fundamental astronomical periods for precession and obliquity. At the same time, the amplitudes of the different terms in the development of the obliquity are undergoing a relative enlargement of about 50 percent at 2 x 10(exp 9) yr BP but the independent term is increasing very weakly (less than 0.1 percent). In other words, the value of the obliquity, which lies within a range of 21.7 to 24.9 deg over the Quarternary was restricted to a range of 22.5 to 24.1 deg at 2 x 10(exp 9) yr BP. On the other hand, the amplitudes in the development of the climatic precession do not change. Moreover, these changes in the frequencies and amplitudes for both obliquity and climatic precession are larger for longer period terms. Finally, the periods in the eccentricity development are not influenced by the variation of the lunar distance. But the motion of the solar system, especially of the inner planets, was shown to be chaotic. It means that it is impossible to compute the exact motion of the planets over more than about 100 Myr, and the fundamental frequencies of the systems are not fixed quantities, but are slowly varying with time. As long as we consider the most important terms, the maximum deviation from the present-day value of the 19-kyr precessional period due to the chaotic motion of the solar system only does not reach more than a few tens of years around 80 Myr BP. Therefore the shortening of the obliquity

  12. Nonmonotonous variation of DNA angular separation during asymmetric pulsed field electrophoresis.

    PubMed

    Nazemifard, Neda; Bhattacharjee, Subir; Masliyah, Jacob H; Harrison, D Jed

    2013-09-01

    Asymmetric pulsed field electrophoresis within crystalline arrays is used to generate angular separation of DNA molecules. Four regimes of the frequency response are observed, a low frequency rise in angular separation, a plateau, a subsequent decline, and a second plateau at higher frequencies. It is shown that the frequency response for different sized DNA is governed by the relation between pulse time and the reorientation time of DNA molecules. The decline in angular separation at higher frequencies has not previously been analyzed. Real-time videos of single DNA molecules migrating under high frequency-pulsed electric field show the molecules no longer follow the head to tail switching, ratchet mechanism seen at lower frequencies. Once the pulse period is shorter than the reorientation time, the migration mechanism changes significantly. The molecule reptates along the average direction of the two electric fields, which reduces the angular separation. A freely jointed chain model of DNA is developed where the porous structure is represented with a hexagonal array of obstacles. The model qualitatively predicts the variation of DNA angular separation with respect to frequency.

  13. CW dual-frequency MOPA laser with frequency separation of 45 GHz.

    PubMed

    Hu, Miao; Zheng, Yaoyuan; Cai, Ju; Zhang, Guiju; Li, Qiliang; Zhou, Xuefang; Wei, Yizhen; Lu, Yang

    2015-04-20

    A CW dual-frequency master oscillator power amplifier (MOPA) laser system with dozens of gigahertz (GHz) frequency separation is presented. The MOPA system consists of a monolithic microchip seed laser and a double-end pumped traveling wave power amplifier. The short length of seed laser cavity guarantees the seed signal with a large frequency separation (above 53 GHz) but low output power (below 247.8 mW). By adding a long and low-doped active medium laser amplifier stage, a significant increase in laser power and an improvement in beam quality are obtained. After fine temperature tuning of seed laser cavity for "spectra matching", a 2.40 W dual-frequency laser signal with 45 GHz frequency separation is achieved.

  14. Development of a frequency-separated knob with variable change rates by rotation speed.

    PubMed

    Kim, Huhn; Ham, Dong-Han

    2014-11-01

    The principle of frequency separation is a design method to display different information or feedback in accordance with the frequency of interaction between users and systems. This principle can be usefully applied to the design of knobs. Particularly, their rotation speed can be a meaningful criterion for applying the principle. Hence a knob can be developed, which shows change rates varying depending on its rotation speed. Such a knob would be more efficient than conventional knobs with constant change rate. We developed a prototype of frequency-separated knobs that has different combinations of the number of rotation speed steps and the size of the variation of change rate. With this prototype, we conducted an experiment to examine whether a speed frequency-separated knob enhances users' task performance. The results showed that the newly designed knob was effective in enhancing task performance, and that task efficiency was the best when its change rate increases exponentially and its rotation speed has three steps. We conducted another experiment to investigate how a more rapid exponential increase of change rate and a more number of steps of rotation speed influence users' task performance. The results showed that merely increasing both the size of the variation of change rates and the number of speed steps did not result in better task performance. Although two experimental results cannot easily be generalized to other contexts, they still offer practical information useful for designing a speed frequency-separated knob in various consumer electronics and control panels of industrial systems.

  15. 46 CFR 111.01-17 - Voltage and frequency variations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Voltage and frequency variations. 111.01-17 Section 111.01-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General § 111.01-17 Voltage and frequency variations....

  16. Implementation of the Frequency Separation Technique in general lineshape codes

    NASA Astrophysics Data System (ADS)

    Alexiou, S.

    2013-06-01

    The Frequency Separation Technique (FST) has been proposed and theoretically documented. It is a technique capable of unifying and improving lineshape calculations, for both accuracy and speed. In this work, we briefly recall its key features and advantages and present a practical way of implementing it in lineshape codes. We note that the FST is a general technique, capable of working with practically any modern lineshape framework that can either employ or go beyond the standard framework.

  17. Blind separation of multiple vehicle signatures in frequency domain

    NASA Astrophysics Data System (ADS)

    Azimi-Sadjadi, M. R.; Srinivasan, S.

    2005-05-01

    This paper considers the problem of classifying ground vehicles using their acoustic signatures recorded by unattended passive acoustic sensors. Using these sensors, acoustic signatures of a wide variety of sources such as trucks, tanks, personnel, and airborne targets can be recorded. Additionally, interference sources such as wind noise and ambient noise are typically present. The proposed approach in this paper relies on the blind source separation of the recorded signatures of various sources. Two different frequency domain source separation methods have been employed to separate the vehicle signatures that overlap both spectrally and temporally. These methods rely on the frequency domain extension of the independent component analysis (ICA) method and a joint diagonalization of the time varying spectra. Spectral and temporal-dependent features are then extracted from the separated sources using a new feature extraction method and subsequently used for target classification using a three-layer neural network. The performance of the developed algorithms are demonstrated on a subset of a real acoustic signature database acquired from the US Army TACOM-ARDEC, Picatinny Arsenal, NJ.

  18. Interdecadal variation of TC frequency in Japan

    NASA Astrophysics Data System (ADS)

    Choi, Ki-Seon; Cha, Yu-Mi; Kang, Sung-Dae; Kim, Hae-Dong

    2015-07-01

    This study analyzed the climate regime shift using statistical change-point analysis on the time-series tropical cyclone (TC) frequency that affected Japan in July to September. The result showed that there was a significant change in 1995, and since then, it showed a trend of rapidly decreasing frequency. To determine the reason for this, differences between 1995 to 2012 (9512) period and 1978 to 1994 (7894) period were analyzed. First, regarding TC genesis, TCs during the 9512 period showed a characteristic of genesis from the southeast quadrant of the tropical and subtropical western North Pacific and TCs during the 7894 period showed their genesis from the northwest quadrant. Regarding a TC track, TCs in the 7894 period had a strong trend of moving from the far east sea of the Philippines via the East China Sea to the mid-latitude region in East Asia while TCs in the 9512 period showed a trend of moving from the Philippines toward the southern part of China westward. Thus, TC intensity in the 7894 period, which can absorb sufficient energy from the sea as they moved a long distance over the sea, was stronger than that of 9512. Large-scale environments were analyzed to determine the cause of such difference in TC activity occurred between two periods. During the 9512 period, anomalous cold and dry anticyclones were developed strongly in the East Asia continent. As a result, Korea and Japan were affected by the anomalous northerlies thereby preventing TCs in this period from moving toward the mid-latitude region in East Asia. Instead, anomalous easterlies (anomalous trade wind) were developed in the tropical western Pacific so that a high passage frequency from the Philippines to the south China region along the anomalous steering flows was revealed. The characteristics of the anomalous cold and dry anticyclone developed in the East Asia continent were also confirmed by the analysis of air temperature, relative humidity, and sensible heat net flux showing that

  19. 46 CFR 111.01-17 - Voltage and frequency variations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ....01-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General § 111.01-17 Voltage and frequency variations. Unless otherwise stated, electrical equipment must function at variations of at least ±5 percent of rated...

  20. 46 CFR 111.01-17 - Voltage and frequency variations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ....01-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General § 111.01-17 Voltage and frequency variations. Unless otherwise stated, electrical equipment must function at variations of at least ±5 percent of rated...

  1. 46 CFR 111.01-17 - Voltage and frequency variations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ....01-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS General § 111.01-17 Voltage and frequency variations. Unless otherwise stated, electrical equipment must function at variations of at least ±5 percent of rated...

  2. Physics of systematic frequency variations in hydrogen masers

    NASA Technical Reports Server (NTRS)

    Mattison, Edward M.

    1990-01-01

    The frequency stability of hydrogen masers for intervals longer that 10(exp 4) seconds is limited at present by systematic processes. Researchers discuss the physics of frequency-determining mechanisms internal to the maser that are susceptible to systematic variations, and the connections between these internal mechanisms and external environmental factors. Based upon estimates of the magnitudes of systematic effects, they find that the primary internal mechanisms currently limiting long-term maser frequency stability are cavity pulling, at the level parts in 10(exp 15) per day, and wall shift variations, at the level of parts in 10(exp 16) to parts in 10(exp 15) per day. They discuss strategies for reducing systematic frequency variations.

  3. Physics of systematic frequency variations in hydrogen masers

    NASA Technical Reports Server (NTRS)

    Mattison, Edward M.

    1992-01-01

    The frequency stability of hydrogen masers for intervals longer than 10 exp 4 s is currently limited by systematic processes. The physics of frequency-determining mechanisms internal to the maser that are susceptible to systematic variations, and the connections between these internal mechanisms and external environmental factors are discussed. From estimates of the magnitudes of systematic effects, it is found that the primary internal mechanisms limiting long-term maser frequency stability are cavity pulling, at the level of parts in 1015 per day, and wall shift variations, at the level of parts in 10 exp 16 to parts in 10 exp 15 per day. Strategies for reducing systematic frequency variations are discussed.

  4. The structure of a separating turbulent boundary layer. V Frequency effects on periodic unsteady free-stream flows

    NASA Technical Reports Server (NTRS)

    Simpson, R. L.; Shivaprasad, B. G.

    1983-01-01

    The results of experimental trials to obtain measurements of the effects of frequency on the sinusoidal variations in the free stream velocity over a separating turbulent boundary layer are reported. An oscillation frequency of 0.596 Hz was examined, in conjunction with a free stream velocity of 10.18 m/sec. Hot-wire anemometers measured the velocity upstream of the separation and the phase-averaged skin friction, while the velocities in the detached flow zone and the downstream velocity were assayed with a laser anemometer. Large amplitude and phase variations developed at the beginning of separation, producing hysteresis in the relationships between flow parameters. Increases in the free stream velocity decreased the detached shear layer thickness, while in the deceleration segment of the cycle the separated shear layer grew thicker. The results are in a frequency range that are significant for axial compressor blades and helicopter blades.

  5. Ion mobility spectrometer using frequency-domain separation

    DOEpatents

    Martin, Stephen J.; Butler, Michael A.; Frye, Gregory C.; Schubert, W. Kent

    1998-01-01

    An apparatus and method is provided for separating and analyzing chemical species in an ion mobility spectrometer using a frequency-domain technique wherein the ions generated from the chemical species are selectively transported through an ion flow channel having a moving electrical potential therein. The moving electrical potential allows the ions to be selected according to ion mobility, with certain of the ions being transported to an ion detector and other of the ions being effectively discriminated against. The apparatus and method have applications for sensitive chemical detection and analysis for monitoring of exhaust gases, hazardous waste sites, industrial processes, aerospace systems, non-proliferation, and treaty verification. The apparatus can be formed as a microelectromechanical device (i.e. a micromachine).

  6. Ion optics system incorporating radio frequency mass separation

    NASA Technical Reports Server (NTRS)

    Anderson, John R.; Carruth, M. R., Jr.

    1990-01-01

    Results of an experimental study are presented. They show that an RF mass discriminator, based on a Bennett mass spectrometer concept, can be used to discriminate between two species of ions with about a 2-to-1 charge-to-mass ratio. Such a device would be useful for separating monatomic and diatomic oxygen ions in a system designed to simulate the environment that spacecraft encounter in low earth orbit. The influence of changing mass discriminator parameters - such as the spacing of its grids, the amplitude and frequency of RF voltage signals applied to it and the current density of ions incident upon it - on its species discrimination capabilities is discussed. Experimental results are also compared to the results of a simple theoretical model to gain insight into the processes occurring in the discriminator. These results are shown to be in good agreement.

  7. Ion mobility spectrometer using frequency-domain separation

    DOEpatents

    Martin, S.J.; Butler, M.A.; Frye, G.C.; Schubert, W.K.

    1998-08-04

    An apparatus and method are provided for separating and analyzing chemical species in an ion mobility spectrometer using a frequency-domain technique wherein the ions generated from the chemical species are selectively transported through an ion flow channel having a moving electrical potential therein. The moving electrical potential allows the ions to be selected according to ion mobility, with certain of the ions being transported to an ion detector and other of the ions being effectively discriminated against. The apparatus and method have applications for sensitive chemical detection and analysis for monitoring of exhaust gases, hazardous waste sites, industrial processes, aerospace systems, non-proliferation, and treaty verification. The apparatus can be formed as a microelectromechanical device (i.e. a micromachine). 6 figs.

  8. Peculiar variations of white dwarf pulsation frequencies and maestro

    NASA Astrophysics Data System (ADS)

    Dalessio, James Ruland

    In Part I we report on variations of the normal mode frequencies of the pulsating DB white dwarfs EC 20058-5234 and KIC 8626021 and the pulsating DA white dwarf GD 66. The observations of EC 20058-5234 and KIC 8626021 were motivated by the possibility of measuring the plasmon neutrino production rate of a white dwarf, while the observations of GD 66 were part of a white dwarf pulsation timing based planet search. We announce the discovery of periodic and quasi-periodic variations of multiple normal mode frequencies that cannot be due to the presence of planetary companions. We note the possible signature of a planetary companion to EC 20058-5234 and show that GD 66 cannot have a planet in a several AU orbit down to half a Jupiter mass. We also announce the discovery of secular variations of the normal mode frequencies of all three stars that are inconsistent with cooling alone. Importantly, the rates of period change of several modes of KIC 8626021 are consistent with evolutionary cooling, but are not yet statistically significant. These modes offer the best possibility of measuring the neutrino production rate in a white dwarf. We also observe periodic and secular variations in the frequency of a combination mode that exactly matches the variations predicted by the parent modes, strong observational evidence that combination modes are created by the convection zone and are not normal modes. Periodic variations in the amplitudes of many of these modes is also noted. We hypothesize that these frequency variations are caused by complex variations of the magnetic field strength and geometry, analogous to behavior observed in the Sun. In Part II we describe the MAESTRO software framework and the MAESTRO REDUCE algorithm. MAESTRO is a collection of astronomy specific MatLab software developed by the Whole Earth Telescope. REDUCE is an an algorithm that can extract the brightness of stars on a set of CCD images with minimal configuration and human interaction. The key to

  9. Gravitational dynamos and the low-frequency geomagnetic secular variation

    PubMed Central

    Olson, P.

    2007-01-01

    Self-sustaining numerical dynamos are used to infer the sources of low-frequency secular variation of the geomagnetic field. Gravitational dynamo models powered by compositional convection in an electrically conducting, rotating fluid shell exhibit several regimes of magnetic field behavior with an increasing Rayleigh number of the convection, including nearly steady dipoles, chaotic nonreversing dipoles, and chaotic reversing dipoles. The time average dipole strength and dipolarity of the magnetic field decrease, whereas the dipole variability, average dipole tilt angle, and frequency of polarity reversals increase with Rayleigh number. Chaotic gravitational dynamos have large-amplitude dipole secular variation with maximum power at frequencies corresponding to a few cycles per million years on Earth. Their external magnetic field structure, dipole statistics, low-frequency power spectra, and polarity reversal frequency are comparable to the geomagnetic field. The magnetic variability is driven by the Lorentz force and is characterized by an inverse correlation between dynamo magnetic and kinetic energy fluctuations. A constant energy dissipation theory accounts for this inverse energy correlation, which is shown to produce conditions favorable for dipole drift, polarity reversals, and excursions. PMID:18048345

  10. Gravitational dynamos and the low-frequency geomagnetic secular variation.

    PubMed

    Olson, P

    2007-12-18

    Self-sustaining numerical dynamos are used to infer the sources of low-frequency secular variation of the geomagnetic field. Gravitational dynamo models powered by compositional convection in an electrically conducting, rotating fluid shell exhibit several regimes of magnetic field behavior with an increasing Rayleigh number of the convection, including nearly steady dipoles, chaotic nonreversing dipoles, and chaotic reversing dipoles. The time average dipole strength and dipolarity of the magnetic field decrease, whereas the dipole variability, average dipole tilt angle, and frequency of polarity reversals increase with Rayleigh number. Chaotic gravitational dynamos have large-amplitude dipole secular variation with maximum power at frequencies corresponding to a few cycles per million years on Earth. Their external magnetic field structure, dipole statistics, low-frequency power spectra, and polarity reversal frequency are comparable to the geomagnetic field. The magnetic variability is driven by the Lorentz force and is characterized by an inverse correlation between dynamo magnetic and kinetic energy fluctuations. A constant energy dissipation theory accounts for this inverse energy correlation, which is shown to produce conditions favorable for dipole drift, polarity reversals, and excursions.

  11. FINDbase: a worldwide database for genetic variation allele frequencies updated

    PubMed Central

    Georgitsi, Marianthi; Viennas, Emmanouil; Antoniou, Dimitris I.; Gkantouna, Vassiliki; van Baal, Sjozef; Petricoin, Emanuel F.; Poulas, Konstantinos; Tzimas, Giannis; Patrinos, George P.

    2011-01-01

    Frequency of INherited Disorders database (FIND base; http://www.findbase.org) records frequencies of causative genetic variations worldwide. Database records include the population and ethnic group or geographical region, the disorder name and the related gene, accompanied by links to any related external resources and the genetic variation together with its frequency in that population. In addition to the regular data content updates, we report the following significant advances: (i) the systematic collection and thorough documentation of population/ethnic group-specific pharmacogenomic markers allele frequencies for 144 markers in 14 genes of pharmacogenomic interest from different classes of drug-metabolizing enzymes and transporters, representing 150 populations and ethnic groups worldwide; (ii) the development of new data querying and visualization tools in the expanded FINDbase data collection, built around Microsoft’s PivotViewer software (http://www.getpivot.com), based on Microsoft Silverlight technology (http://www.silverlight.net) that facilitates querying of large data sets and visualizing the results; and (iii) the establishment of the first database journal, by affiliating FINDbase with Human Genomics and Proteomics, a new open-access scientific journal, which would serve as a prime example of a non-profit model for sustainable database funding. PMID:21113021

  12. Commissioning of helium injector for coupled radio frequency quadrupole and separated function radio frequency quadrupole accelerator.

    PubMed

    Peng, Shixiang; Chen, Jia; Ren, Haitao; Zhao, Jie; Xu, Yuan; Zhang, Tao; Zhang, Ailing; Xia, Wenlong; Gao, Shuli; Wang, Zhi; Luo, Yuting; Guo, Zhiyu; Chen, Jia'er

    2014-02-01

    A project to study a new type of acceleration structure has been launched at Peking University, in which a traditional radio frequency quadrupole (RFQ) and a separated function radio frequency quadrupole are coupled in one cavity to accelerate the He+ beam. A helium injector for this project is developed. The injector consists of a 2.45 GHz permanent magnet electron cyclotron resonance ion source and a 1.16 m long low energy beam transport (LEBT). The commissioning of this injector was carried out and an onsite test was held in June 2013. A 14 mA He+ beam with the energy of 30 keV has been delivered to the end of the LEBT, where a diaphragm with the diameter of 7 mm is located. The position of the diaphragm corresponds to the entrance of the RFQ electrodes. The beam emittance and fraction were measured after the 7 mm diaphragm. Its rms emittance is about 0.14 π mm mrad and the fraction of He+ is about 99%.

  13. Commissioning of helium injector for coupled radio frequency quadrupole and separated function radio frequency quadrupole accelerator

    SciTech Connect

    Peng, Shixiang Chen, Jia; Ren, Haitao; Zhao, Jie; Xu, Yuan; Zhang, Tao; Xia, Wenlong; Gao, Shuli; Wang, Zhi; Luo, Yuting; Guo, Zhiyu; Zhang, Ailing; Chen, Jia'er

    2014-02-15

    A project to study a new type of acceleration structure has been launched at Peking University, in which a traditional radio frequency quadrupole (RFQ) and a separated function radio frequency quadrupole are coupled in one cavity to accelerate the He+ beam. A helium injector for this project is developed. The injector consists of a 2.45 GHz permanent magnet electron cyclotron resonance ion source and a 1.16 m long low energy beam transport (LEBT). The commissioning of this injector was carried out and an onsite test was held in June 2013. A 14 mA He+ beam with the energy of 30 keV has been delivered to the end of the LEBT, where a diaphragm with the diameter of 7 mm is located. The position of the diaphragm corresponds to the entrance of the RFQ electrodes. The beam emittance and fraction were measured after the 7 mm diaphragm. Its rms emittance is about 0.14 π mm mrad and the fraction of He+ is about 99%.

  14. Dual-band frequency selective surface with large band separation and stable performance

    NASA Astrophysics Data System (ADS)

    Zhou, Hang; Qu, Shao-Bo; Peng, Wei-Dong; Lin, Bao-Qin; Wang, Jia-Fu; Ma, Hua; Zhang, Jie-Qiu; Bai, Peng; Wang, Xu-Hua; Xu, Zhuo

    2012-05-01

    A new technique of designing a dual-band frequency selective surface with large band separation is presented. This technique is based on a delicately designed topology of L- and Ku-band microwave filters. The two band-pass responses are generated by a capacitively-loaded square-loop frequency selective surface and an aperture-coupled frequency selective surface, respectively. A Faraday cage is located between the two frequency selective surface structures to eliminate undesired couplings. Based on this technique, a dual-band frequency selective surface with large band separation is designed, which possesses large band separation, high selectivity, and stable performance under various incident angles and different polarizations.

  15. The role of low-frequency variation in the manifestation of warming trend and ENSO amplitude

    NASA Astrophysics Data System (ADS)

    Yeo, Sae-Rim; Yeh, Sang-Wook; Kim, Kwang-Yul; Kim, WonMoo

    2016-10-01

    Despite the increase in greenhouse gas concentration, the sea surface temperature (SST) over the tropical eastern Pacific during the period of 1999-2014 exhibits less warming trend compared to the earlier decades. It has been noted that this warming hiatus is accompanied by a negative phase of the Pacific Decadal Oscillation (PDO), which represents low-frequency variability over the Pacific. On the other hand, the 2015/2016 El Niño is among the strongest comparable to the 1997/1998 event, which coincides with the recently altered PDO phase from negative to positive. These observational evidences have generated substantial interest in the role of low-frequency variations in modulating El Niño-Southern Oscillation amplitude as well as manifestation of warming signal in the tropical Pacific. Therefore, it is necessary to appropriately separate low-frequency variability and global warming signal from SST records. Here, we present three primary modes of global SST that include secular warming trend, low-frequency variability, and biennial oscillation. Based on the independent behavior of these three modes, global warming is clearly continuing but its manifestation is enhanced (depressed) when the low-frequency variation is in the positive (negative) phase. Further, possibility of strong El Niño increases under the positive phase of the low-frequency mode, which amplifies warming over the tropical eastern Pacific. Indeed, the strong 2015/2016 El Niño is largely attributed to the positive phase of the low-frequency mode. In order to examine the climate models' ability to simulate the three SST modes as obtained in the observational record, the Coupled Model Intercomparison Project phase 5 (CMIP5) datasets are also analyzed. The spatial and temporal characteristics of the three modes have been replicated closely by the selected CMIP5 models forced by the historical condition, which provides an analogy of the interplay of three modes in the observed tropical Pacific SST.

  16. Single channel speech separation in modulation frequency domain based on a novel pitch range estimation method

    NASA Astrophysics Data System (ADS)

    Mahmoodzadeh, Azar; Abutalebi, Hamid Reza; Soltanian-Zadeh, Hamid; Sheikhzadeh, Hamid

    2012-12-01

    Computational Auditory Scene Analysis (CASA) has been the focus in recent literature for speech separation from monaural mixtures. The performance of current CASA systems on voiced speech separation strictly depends on the robustness of the algorithm used for pitch frequency estimation. We propose a new system that estimates pitch (frequency) range of a target utterance and separates voiced portions of target speech. The algorithm, first, estimates the pitch range of target speech in each frame of data in the modulation frequency domain, and then, uses the estimated pitch range for segregating the target speech. The method of pitch range estimation is based on an onset and offset algorithm. Speech separation is performed by filtering the mixture signal with a mask extracted from the modulation spectrogram. A systematic evaluation shows that the proposed system extracts the majority of target speech signal with minimal interference and outperforms previous systems in both pitch extraction and voiced speech separation.

  17. Multibeam single frequency synthetic aperture radar processor for imaging separate range swaths

    NASA Technical Reports Server (NTRS)

    Jain, A. (Inventor)

    1982-01-01

    A single-frequency multibeam synthetic aperture radar for large swath imaging is disclosed. Each beam illuminates a separate ""footprint'' (i.e., range and azimuth interval). The distinct azimuth intervals for the separate beams produce a distinct Doppler frequency spectrum for each beam. After range correlation of raw data, an optical processor develops image data for the different beams by spatially separating the beams to place each beam of different Doppler frequency spectrum in a different location in the frequency plane as well as the imaging plane of the optical processor. Selection of a beam for imaging may be made in the frequency plane by adjusting the position of an aperture, or in the image plane by adjusting the position of a slit. The raw data may also be processed in digital form in an analogous manner.

  18. Time Variation of the Distance Separating Bomb and Dive Bomber Subsequent to Bomb Release

    NASA Technical Reports Server (NTRS)

    Mathews, Charles W.

    1952-01-01

    A study has been made of the variation of the distance separating bomb and aircraft with time after release as applied to dive-bombing operations, Separation distances determined from this study are presented in terms of two variables only, dive angle and maximum airplane accelerometer reading; the values of separation distance include the effects of delay in initiation of the pull-out and lag in attainment of the maximum normal acceleration.Contains analysis and calculations of the separation distances between bomb and dive bomber following bomb release, Separation distances as determined by the dive angle and the maximum airplane accelerometer reading are presented in a single chart.

  19. Lab-chip HPLC with integrated droplet-based microfluidics for separation and high frequency compartmentalisation.

    PubMed

    Kim, Jin-Young; Cho, Soong-Won; Kang, Dong-Ku; Edel, Joshua B; Chang, Soo-Ik; deMello, Andrew J; O'Hare, Danny

    2012-09-21

    We demonstrate the integration of a droplet-based microfluidic device with high performance liquid chromatography (HPLC) in a monolithic format. Sequential operations of separation, compartmentalisation and concentration counter were conducted on a monolithic chip. This describes the use of droplet-based microfluidics for the preservation of chromatographic separations, and its potential application as a high frequency fraction collector.

  20. Separation of structural modes and harmonic frequencies in Operational Modal Analysis using random decrement

    NASA Astrophysics Data System (ADS)

    Modak, S. V.

    2013-12-01

    Operational Modal Analysis (OMA) is used to extract modal parameters of a structure on the basis of their output response measured during operation. OMA, when applied to mechanical engineering structures is often faced with the problem of harmonics present in the output response. A complex structure may have many dominant frequency components in its response frequency spectrum. These may contain frequency components associated with resonant frequencies of the structure, which and the associated mode shapes and the damping factors represent the data of interest, but may also contain frequencies or harmonics associated with the excitation sources. Since in OMA the characteristics of the excitation sources are not known, one of the problems lies in separating the resonant frequencies from the harmonic excitation frequencies. Any error in this regard may lead to an error in modal identification with the consequence that a harmonic may be construed as a structural mode and vice versa. This issue is addressed in this paper and a method is presented for separating resonant frequencies from harmonic excitation frequencies using random decrement of the response. The principle of the method is presented using an analytical study on a single degree of freedom system. The effectiveness of the method is then demonstrated through numerical studies on a lumped parameter multi-degree of freedom system and a simulated plate structure. Detection of single and multiple harmonics in the response that are well separated as well as close to resonant frequencies are considered.

  1. High frequency behavior of a rolling ball and simplification of the separation equation

    NASA Astrophysics Data System (ADS)

    Rutstam, Nils

    2013-05-01

    The Chaplygin separation equation for a rolling axisymmetric ball has an algebraic expression for the effective potential V ( z = cos θ, D, λ) that is difficult to analyze. We simplify this expression for the potential and find a 2-parameter family for when the potential becomes a rational function of z = cos θ. Then this separation equation becomes similar to the separation equation for the heavy symmetric top. For nutational solutions of a rolling sphere, we study a high frequency ω 3-dependence of the width of the nutational band, the depth of motion above V( z min, D, λ) and the ω 3-dependence of nutational frequency tfrac{{2π }} {T}.

  2. Auditory scene analysis: the interaction of stimulation rate and frequency separation on pre-attentive grouping.

    PubMed

    De Sanctis, Pierfilippo; Ritter, Walter; Molholm, Sophie; Kelly, Simon P; Foxe, John J

    2008-03-01

    Segregation of auditory inputs into meaningful acoustic groups is a key element of auditory scene analysis. Previously, we showed that two interwoven sets of tones differing widely along multiple feature dimensions (duration, pitch and location) were pre-attentively separated into different groups, and that tones separated in this manner did not elicit the mismatch negativity component with respect to each other. Grouping was studied with human subjects using a stimulus rate too slow to induce streaming. Here, we varied the separation of tone sequences along a single feature dimension, i.e. frequency. Frequency differences were either 24 Hz (small) or 1054 Hz (large). Two relatively slow stimulus rates were used (2.7 or 1 tone/s) to explicitly investigate grouping outside the so-called 'streaming effect', which requires rates of about 4 tones/s or faster. Two tones were presented in a quasi-random manner with embedded trains of one to four identical tones in a row. Deviants were defined as frequency switches after trains of four identical tones. Mismatch negativity was only elicited for small frequency switches at the slower stimulation rate. The data indicate that pre-attentive grouping of tones occurred when the frequency difference that separated them was large, regardless of stimulation rate. For small frequency differences, inputs were only grouped separately when the stimulation rate was relatively fast.

  3. The use of extrapolation concepts to augment the Frequency Separation Technique

    NASA Astrophysics Data System (ADS)

    Alexiou, Spiros

    2015-03-01

    The Frequency Separation Technique (FST) is a general method formulated to improve the speed and/or accuracy of lineshape calculations, including strong overlapping collisions, as is the case for ion dynamics. It should be most useful when combined with ultrafast methods, that, however have significant difficulties when the impact regime is approached. These difficulties are addressed by the Frequency Separation Technique, in which the impact limit is correctly recovered. The present work examines the possibility of combining the Frequency Separation Technique with the addition of extrapolation to improve results and minimize errors resulting from the neglect of fast-slow coupling and thus obtain the exact result with a minimum of extra effort. To this end the adequacy of one such ultrafast method, the Frequency Fluctuation Method (FFM) for treating the nonimpact part is examined. It is found that although the FFM is unable to reproduce the nonimpact profile correctly, its coupling with the FST correctly reproduces the total profile.

  4. Frequency variations of discrete cranial traits in major human populations. III. Hyperostotic variations

    PubMed Central

    HANIHARA, TSUNEHIKO; ISHIDA, HAJIME

    2001-01-01

    Seven discrete cranial traits usually categorised as hyperostotic characters, the medial palatine canal, hypoglossal canal bridging, precondylar tubercle, condylus tertius, jugular foramen bridging, auditory exostosis, and mylohyoid bridging were investigated in 81 major human population samples from around the world. Significant asymmetric occurrences of the bilateral traits were detected in the medial palatine canal and jugular foramen bridging in several samples. Significant intertrait associations were found between some pairs of the traits, but not consistently across the large geographical samples. The auditory exostosis showed a predominant occurrence in males. With the exception of the auditory exostosis and mylohyoid bridging in a few samples, significant sex differences were slight. The frequency distributions of the traits (except for the auditory exostosis) showed some interregional clinality and intraregional discontinuity, suggesting that genetic drift could have contributed to the observed pattern of variation. PMID:11554504

  5. Read distance performance and variation of 5 low-frequency radio frequency identification panel transceiver manufacturers.

    PubMed

    Ryan, S E; Blasi, D A; Anglin, C O; Bryant, A M; Rickard, B A; Anderson, M P; Fike, K E

    2010-07-01

    Use of electronic animal identification technologies by livestock managers is increasing, but performance of these technologies can be variable when used in livestock production environments. This study was conducted to determine whether 1) read distance of low-frequency radio frequency identification (RFID) transceivers is affected by type of transponder being interrogated; 2) read distance variation of low-frequency RFID transceivers is affected by transceiver manufacturer; and 3) read distance of various transponder-transceiver manufacturer combinations meet the 2004 United States Animal Identification Plan (USAIP) bovine standards subcommittee minimum read distance recommendation of 60 cm. Twenty-four transceivers (n = 5 transceivers per manufacturer for Allflex, Boontech, Farnam, and Osborne; n = 4 transceivers for Destron Fearing) were tested with 60 transponders [n = 10 transponders per type for Allflex full duplex B (FDX-B), Allflex half duplex (HDX), Destron Fearing FDX-B, Farnam FDX-B, and Y-Tex FDX-B; n = 6 for Temple FDX-B (EM Microelectronic chip); and n = 4 for Temple FDX-B (HiTag chip)] presented in the parallel orientation. All transceivers and transponders met International Organization for Standardization 11784 and 11785 standards. Transponders represented both one-half duplex and full duplex low-frequency air interface technologies. Use of a mechanical trolley device enabled the transponders to be presented to the center of each transceiver at a constant rate, thereby reducing human error. Transponder and transceiver manufacturer interacted (P < 0.0001) to affect read distance, indicating that transceiver performance was greatly dependent upon the transponder type being interrogated. Twenty-eight of 30 combinations of transceivers and transponders evaluated met the minimum recommended USAIP read distance. The mean read distance across all 30 combinations was 45.1 to 129.4 cm. Transceiver manufacturer and transponder type interacted to affect read

  6. Multibeam single frequency synthetic aperture radar processor for imaging separate range swaths

    NASA Technical Reports Server (NTRS)

    Jain, A. (Inventor)

    1979-01-01

    A method and apparatus are described for single frequency multibeam imaging of multiple strips of range swath at high range intervals for those applications where it is desirable to cover a range swath much greater than is possible for a given interpulse interval. Data from a single frequency synthetic aperture radar (in which beam parameters are adjusted so that the return from each successive swath is received during successive interpulse periods) are separated in Dopple frequency for the return from each beam at the frequency plane of the processor. Alternatively, the image formed by each beam may be spatially separated in the azimuth direction and successively selected by positioning an appropriate slit in the recording plane of the processor.

  7. Low-frequency and common genetic variation in ischemic stroke

    PubMed Central

    Malik, Rainer; Traylor, Matthew; Pulit, Sara L.; Bevan, Steve; Hopewell, Jemma C.; Holliday, Elizabeth G.; Zhao, Wei; Abrantes, Patricia; Amouyel, Philippe; Attia, John R.; Battey, Thomas W.K.; Berger, Klaus; Boncoraglio, Giorgio B.; Chauhan, Ganesh; Cheng, Yu-Ching; Chen, Wei-Min; Clarke, Robert; Cotlarciuc, Ioana; Debette, Stephanie; Falcone, Guido J.; Ferro, Jose M.; Gamble, Dale M.; Ilinca, Andreea; Kittner, Steven J.; Kourkoulis, Christina E.; Lemmens, Robin; Levi, Christopher R.; Lichtner, Peter; Lindgren, Arne; Liu, Jingmin; Meschia, James F.; Mitchell, Braxton D.; Oliveira, Sofia A.; Pera, Joana; Reiner, Alex P.; Rothwell, Peter M.; Sharma, Pankaj; Slowik, Agnieszka; Sudlow, Cathie L.M.; Tatlisumak, Turgut; Thijs, Vincent; Vicente, Astrid M.; Woo, Daniel; Seshadri, Sudha; Saleheen, Danish; Rosand, Jonathan; Markus, Hugh S.; Worrall, Bradford B.

    2016-01-01

    Objective: To investigate the influence of common and low-frequency genetic variants on the risk of ischemic stroke (all IS) and etiologic stroke subtypes. Methods: We meta-analyzed 12 individual genome-wide association studies comprising 10,307 cases and 19,326 controls imputed to the 1000 Genomes (1 KG) phase I reference panel. We selected variants showing the highest degree of association (p < 1E-5) in the discovery phase for replication in Caucasian (13,435 cases and 29,269 controls) and South Asian (2,385 cases and 5,193 controls) samples followed by a transethnic meta-analysis. We further investigated the p value distribution for different bins of allele frequencies for all IS and stroke subtypes. Results: We showed genome-wide significance for 4 loci: ABO for all IS, HDAC9 for large vessel disease (LVD), and both PITX2 and ZFHX3 for cardioembolic stroke (CE). We further refined the association peaks for ABO and PITX2. Analyzing different allele frequency bins, we showed significant enrichment in low-frequency variants (allele frequency <5%) for both LVD and small vessel disease, and an enrichment of higher frequency variants (allele frequency 10% and 30%) for CE (all p < 1E-5). Conclusions: Our findings suggest that the missing heritability in IS subtypes can in part be attributed to low-frequency and rare variants. Larger sample sizes are needed to identify the variants associated with all IS and stroke subtypes. PMID:26935894

  8. Audio source separation with multiple microphones on time-frequency representations

    NASA Astrophysics Data System (ADS)

    Sawada, Hiroshi

    2013-05-01

    This paper presents various source separation methods that utilize multiple microphones. We classify them into two classes. Methods that fall into the first class apply independent component analysis (ICA) or Gaussian mixture model (GMM) to frequency bin-wise observations, and then solve the permutation problem to reconstruct separated signals. The second type of method extends non-negative matrix factorization (NMF) to a multimicrophone situation, in which NMF bases are clustered according to their spatial properties. We have a unified understanding that all methods analyze a time-frequency representation with an additional microphone axis.

  9. Variation in the Input: A Case Study of Manner Class Frequencies

    ERIC Educational Resources Information Center

    Daland, Robert

    2013-01-01

    What are the sources of variation in the input, and how much do they matter for language acquisition? This study examines frequency variation in manner-of-articulation classes in child and adult input. The null hypothesis is that segmental frequency distributions of language varieties are unigram (modelable by stationary, ergodic processes), and…

  10. Frequency variations of solar radio zebras and their power-law spectra

    NASA Astrophysics Data System (ADS)

    Karlický, M.

    2014-01-01

    Context. During solar flares several types of radio bursts are observed. The fine striped structures of the type IV solar radio bursts are called zebras. Analyzing them provides important information about the plasma parameters of their radio sources. We present a new analysis of zebras. Aims: Power spectra of the frequency variations of zebras are computed to estimate the spectra of the plasma density variations in radio zebra sources. Methods: Frequency variations of zebra lines and the high-frequency boundary of the whole radio burst were determined with and without the frequency fitting. The computed time dependencies of these variations were analyzed with the Fourier method. Results: First, we computed the variation spectrum of the high-frequency boundary of the whole radio burst, which is composed of several zebra patterns. This power spectrum has a power-law form with a power-law index -1.65. Then, we selected three well-defined zebra-lines in three different zebra patterns and computed the spectra of their frequency variations. The power-law indices in these cases are found to be in the interval between -1.61 and -1.75. Finally, assuming that the zebra-line frequency is generated on the upper-hybrid frequency and that the plasma frequency ωpe is much higher than the electron-cyclotron frequency ωce, the Fourier power spectra are interpreted to be those of the electron plasma density in zebra radio sources.

  11. Frequency spectra of short-period variations of cosmic ray

    NASA Technical Reports Server (NTRS)

    Antonova, V. P.; Zusmanovich, A. G.

    1985-01-01

    Frequency spectra for different periods of solar activity were calculated by 5-minutes data of a neutron super-monitor, (altitude 3340 m, cutoff rigidity is 6, 7 GV, counting rate is about 4.5.10 per hour). It was shown that shifting of the spectrum power from low-frequency range to high-frequency range takes place from minimum to maximum of the solar activity. It was reliably distinguished the peak with 160-minutes period coincided with the period of the Sun's atmosphere oscillation and some types of geomagnetic pulsation by the method of accumulation of the frequency spectra. It was conducted the comparison of cosmic ray spectra with spectra of geomagnetic field for the same point of the registration and at the same period.

  12. Wide Angle, Single Screen, Gridded Square-Loop Frequency Selective Surface for Diplexing Two Closely Separated Frequency Bands

    NASA Technical Reports Server (NTRS)

    Wu, Te-Kao (Inventor)

    1996-01-01

    The design and performance of a wide angle, single screen, frequency selective surface (FSS) with gridded square-loop path elements are described for diplexing closely separated signal bands, for example, X- and Ku-band signals in an Orbiting Very Long Baseline Interferometer (OVLBI) earth station reflector antenna system, as well as other applications such as military and commercial communications via satellites. Excellent agreement is obtained between the predicted and measured results of this FSS design using the gridded square-loop patch elements sandwiched between 0.0889 cm thick tetrafluoroethylene fluorocarbon polymer (PTFE) slabs. Resonant frequency drift is reduced by 1 GHz with an incidence angle from 0 deg normal to 40 deg from normal.

  13. A frequency-control particle separation device based on resultant effects of electroosmosis and dielectrophoresis

    NASA Astrophysics Data System (ADS)

    Lin, Shiang-Chi; Tung, Yi-Chung; Lin, Chih-Ting

    2016-08-01

    Particle separation plays an important role in microfluidic sample preparation for various biomedical applications. In this paper, we report a particle manipulation and separation scheme using a microfluidic device based on low-volume/low-voltage electrokinetic frequency modulation. Utilizing a circular micro-electrode array, both electroosmosis and dielectrophoresis can be contributed to manipulate particles in the device by controlling the frequency of applied sinusoidal travelling wave signals. Theoretical simulations based on finite-element methods are employed to establish fundamental understanding of the developed scheme. For experimental demonstration, polystyrene beads (6 μm in diameter) and human promyelocytic leukaemia cells (HL-60) are used to validate the frequency-modulation effect. Furthermore, different diameter polystyrene beads (6 μm and 10 μm in diameter) are mixed to show potentials of precise particle separations (˜90% efficiency) by the reported frequency-controlled electrokinetic device. The developed technique can be exploited as an actuation scheme and particle manipulation method for microfluidic sample preparations of low ionic concentration samples.

  14. Enhanced Mixture Separations of Metal Adducted Tetrasaccharides Using Frequency Encoded Ion Mobility Separations and Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Morrison, Kelsey A.; Bendiak, Brad K.; Clowers, Brian H.

    2016-10-01

    Using five isomeric tetrasaccharides in combination with seven multivalent metals, the impact on mobility separations and resulting CID spectra were examined using a hybrid ion mobility atmospheric pressure drift tube system coupled with a linear ion trap. By enhancing the duty cycle of the drift tube system using a linearly chirped frequency, the collision-induced dissociation spectra were encoded in the mobility domain according to the drift times of each glycan isomer precursor. Differential fragmentation patterns correlated with precursor drift times ensured direct assignment of fragments with precursor structure whether as individual standards or in a mixture of isomers. In addition to certain metal ions providing higher degrees of separation than others, in select cases more than one arrival time distribution was observed for a single pure carbohydrate isomer. These observations suggest the existence of alternative coordination sites within a single monomeric species, but more interesting was the observation of different fragmentation ion yields for carbohydrate dimers formed through metal adduction. Positive-ion data were also compared with negative-ion species, where dimer formation did not occur and single peaks were observed for each isomeric tetrasaccharide-alditol. This enhanced analytical power has implications not only for carbohydrate molecules but also for a wide variety of complex mixtures of molecules where dissociation spectra may potentially be derived from combinations of monomeric, homodimeric, and heterodimeric species having identical nominal m/z values.

  15. Adaptive frequency-separation-based energy management system for electric vehicles

    NASA Astrophysics Data System (ADS)

    Florescu, Adrian; Bacha, Seddik; Munteanu, Iulian; Bratcu, Antoneta Iuliana; Rumeau, Axel

    2015-04-01

    This paper deals with an adaptive frequency-based power sharing method between batteries and ultracapacitors (UC) as power sources within an electric vehicle. An adaptive frequency splitter is used for routing the low-frequency content of power demand into the battery and its high-frequency content into the UC system, taking profit from the UC as a peak power unit. Autonomy may thus be increased while preserving battery state of health and ensuring that UC voltage variations remain confined within certain desired range. Results obtained by real-time experiments on a dedicated test rig validate the proposed energy management approach and recommend it to be applied as power source coordination method to microgrids in general.

  16. Polarity separating optical orthogonal frequency division multiplexing for free-space visible light communications

    NASA Astrophysics Data System (ADS)

    Li, Jianfeng; Huang, Zhitong; Li, Jianke; Liu, Xiaoshuang

    2017-02-01

    A modulation format, polarity separating optical orthogonal frequency division multiplexing (PSO-OFDM), is proposed to mitigate the light-emitting diode (LED) nonlinearity for visible light communication systems. A polarity separator is used to divide the OFDM signal in time domain x(t) into two parts: x+(t) and x-(t), which will be transmitted parallelly from the different LEDs and overlap linearly in free space to realize PSO-OFDM. The experimental results demonstrate that PSO-OFDM has high spectral efficiency and suffers less nonlinear distortions than other methods. Employing PSO-OFDM, the modulation index and bit error rate performance can be significantly enhanced.

  17. Aero-acoustics source separation with sparsity inducing priors in the frequency domain

    NASA Astrophysics Data System (ADS)

    Schwander, Olivier; Picheral, José; Gac, Nicolas; Mohammad-Djafari, Ali; Blacodon, Daniel

    2015-01-01

    The characterization of acoustic sources is of great interest in many industrial applications, in particular for the aeronautic or automotive industry for the development of new products. While localization of sources using observations from a wind tunnel is a well-known subject, the characterization and separation of the sources still needs to be explored. We present here a Bayesian approach for sources separation. Two prior modeling of the sources are considered: a sparsity inducing prior in the frequency domain and an autoregressive model in the time domain. The proposed methods are evaluated on synthetic data simulating noise sources emitting from an airfoil inside a wind tunnel.

  18. Determining Optimum C-Field Settings that Minimize Output Frequency Variations in Cesium Atomic Frequency Standards

    DTIC Science & Technology

    1989-11-01

    current setting is probably on the order of parts in lo4 in our laboratory environment over the three months during which data were taken; this...hardware and long-term frequency-stability measurements. This work was supported, in part , by the U.S. Air Force Space Systems Division under Contract...Long-Term Stability in Cesium Beam Frequency Standards," IEEE Trans. Ultrasonics , Ferroelectronics, and Frequency Control UFFC-34 [6], 598-601 (Novem

  19. Separation of Intercepted Multi-Radar Signals Based on Parameterized Time-Frequency Analysis

    NASA Astrophysics Data System (ADS)

    Lu, W. L.; Xie, J. W.; Wang, H. M.; Sheng, C.

    2016-09-01

    Modern radars use complex waveforms to obtain high detection performance and low probabilities of interception and identification. Signals intercepted from multiple radars overlap considerably in both the time and frequency domains and are difficult to separate with primary time parameters. Time-frequency analysis (TFA), as a key signal-processing tool, can provide better insight into the signal than conventional methods. In particular, among the various types of TFA, parameterized time-frequency analysis (PTFA) has shown great potential to investigate the time-frequency features of such non-stationary signals. In this paper, we propose a procedure for PTFA to separate overlapped radar signals; it includes five steps: initiation, parameterized time-frequency analysis, demodulating the signal of interest, adaptive filtering and recovering the signal. The effectiveness of the method was verified with simulated data and an intercepted radar signal received in a microwave laboratory. The results show that the proposed method has good performance and has potential in electronic reconnaissance applications, such as electronic intelligence, electronic warfare support measures, and radar warning.

  20. Silent (painless) thyroiditis. Evidence of a geographic variation in frequency

    SciTech Connect

    Vitug, A.C.; Goldman, J.M.

    1985-03-01

    Recent reports suggest that 14% to 23% of thyrotoxic patients have silent (painless) thyroiditis, a newly described syndrome characterized by transient thyrotoxicosis with a low radioactive iodine uptake. A three-year review at a Brooklyn (NY) hospital showed only one definite and three possible cases of silent thyroiditis among 86 thyrotoxic patients. At most, 4% to 5% of thyrotoxic patients had silent thyroiditis. The authors suggest a geographic variation in this syndrome. Most cases and the largest series are from Japan and the Great Lakes area of North America. The latter may be related to increased iodine intake over many years in a previously endemic area of hypoiodidism and goiter, although other local factors may also be involved.

  1. Tectorial Membrane Morphological Variation: Effects upon Stimulus Frequency Otoacoustic Emissions

    PubMed Central

    Bergevin, Christopher; Velenovsky, David S.; Bonine, Kevin E.

    2010-01-01

    The tectorial membrane (TM) is widely believed to play an important role in determining the ear's ability to detect and resolve incoming acoustic information. While it is still unclear precisely what that role is, the TM has been hypothesized to help overcome viscous forces and thereby sharpen mechanical tuning of the sensory cells. Lizards present a unique opportunity to further study the role of the TM given the diverse inner-ear morphological differences across species. Furthermore, stimulus-frequency otoacoustic emissions (SFOAEs), sounds emitted by the ear in response to a tone, noninvasively probe the frequency selectivity of the ear. We report estimates of auditory tuning derived from SFOAEs for 12 different species of lizards with widely varying TM morphology. Despite gross anatomical differences across the species examined herein, low-level SFOAEs were readily measurable in all ears tested, even in non-TM species whose basilar papilla contained as few as 50–60 hair cells. Our measurements generally support theoretical predictions: longer delays/sharper tuning features are found in species with a TM relative to those without. However, SFOAEs from at least one non-TM species (Anolis) with long delays suggest there are likely additional micromechanical factors at play that can directly affect tuning. Additionally, in the one species examined with a continuous TM (Aspidoscelis) where cell-to-cell coupling is presumably relatively stronger, delays were intermediate. This observation appears consistent with recent reports that suggest the TM may play a more complex macromechanical role in the mammalian cochlea via longitudinal energy distribution (and thereby affect tuning). Although significant differences exist between reptilian and mammalian auditory biophysics, understanding lizard OAE generation mechanisms yields significant insight into fundamental principles at work in all vertebrate ears. PMID:20712989

  2. Variation in the resting frequency of Rhinolophus pusillus in Mainland China: effect of climate and implications for conservation.

    PubMed

    Jiang, Tinglei; Metzner, Walter; You, Yuyan; Liu, Sen; Lu, Guanjun; Li, Shi; Wang, Lei; Feng, Jiang

    2010-10-01

    This study describes variation patterns in the constant frequency of echolocation calls emitted at rest and when not flying ("resting frequency" RF) of the least horseshoe bat, Rhinolophus pusillus, on a broad geographical scale and in response to local climatic variables. Significant differences in RF were observed among populations throughout the species range in Mainland China, and this variation was positively and significantly related to climate conditions, especially environmental humidity, but the variability was only weakly associated with geographical distance. Sex dimorphism in the RF of R. pusillus may imply that female and male might keep their frequencies within a narrow range for sex recognition. Moreover, bats adjusted resting frequency to humidity, which may imply partitioning diet by prey size or the influence of rainfall noise. The results indicate that bats adjust echolocation call frequency to adapt to environmental conditions. Therefore, environmental selection shape the diversity of echolocation call structure of R. pusillus in geographically separated populations, and conservation efforts should focus on changes in local climate and effects of environmental noise.

  3. Underdetermined Blind Source Separation with Variational Mode Decomposition for Compound Roller Bearing Fault Signals

    PubMed Central

    Tang, Gang; Luo, Ganggang; Zhang, Weihua; Yang, Caijin; Wang, Huaqing

    2016-01-01

    In the condition monitoring of roller bearings, the measured signals are often compounded due to the unknown multi-vibration sources and complex transfer paths. Moreover, the sensors are limited in particular locations and numbers. Thus, this is a problem of underdetermined blind source separation for the vibration sources estimation, which makes it difficult to extract fault features exactly by ordinary methods in running tests. To improve the effectiveness of compound fault diagnosis in roller bearings, the present paper proposes a new method to solve the underdetermined problem and to extract fault features based on variational mode decomposition. In order to surmount the shortcomings of inadequate signals collected through limited sensors, a vibration signal is firstly decomposed into a number of band-limited intrinsic mode functions by variational mode decomposition. Then, the demodulated signal with the Hilbert transform of these multi-channel functions is used as the input matrix for independent component analysis. Finally, the compound faults are separated effectively by carrying out independent component analysis, which enables the fault features to be extracted more easily and identified more clearly. Experimental results validate the effectiveness of the proposed method in compound fault separation, and a comparison experiment shows that the proposed method has higher adaptability and practicability in separating strong noise signals than the commonly-used ensemble empirical mode decomposition method. PMID:27322268

  4. Underdetermined Blind Source Separation with Variational Mode Decomposition for Compound Roller Bearing Fault Signals.

    PubMed

    Tang, Gang; Luo, Ganggang; Zhang, Weihua; Yang, Caijin; Wang, Huaqing

    2016-06-16

    In the condition monitoring of roller bearings, the measured signals are often compounded due to the unknown multi-vibration sources and complex transfer paths. Moreover, the sensors are limited in particular locations and numbers. Thus, this is a problem of underdetermined blind source separation for the vibration sources estimation, which makes it difficult to extract fault features exactly by ordinary methods in running tests. To improve the effectiveness of compound fault diagnosis in roller bearings, the present paper proposes a new method to solve the underdetermined problem and to extract fault features based on variational mode decomposition. In order to surmount the shortcomings of inadequate signals collected through limited sensors, a vibration signal is firstly decomposed into a number of band-limited intrinsic mode functions by variational mode decomposition. Then, the demodulated signal with the Hilbert transform of these multi-channel functions is used as the input matrix for independent component analysis. Finally, the compound faults are separated effectively by carrying out independent component analysis, which enables the fault features to be extracted more easily and identified more clearly. Experimental results validate the effectiveness of the proposed method in compound fault separation, and a comparison experiment shows that the proposed method has higher adaptability and practicability in separating strong noise signals than the commonly-used ensemble empirical mode decomposition method.

  5. Experimental Studies of Variations in the Maximum Usable Frequency on Oblique Sounding Paths

    NASA Astrophysics Data System (ADS)

    Cherkashin, Yu. N.; Egorov, I. B.; Uryadov, V. P.; Ponyatov, A. A.

    2003-12-01

    We present the results of experimental studies of variations in the maximum usable frequency (MUF) on the latitudinal (England-Moscow and Khabarovsk-Nizhny Novgorod) and meridional (Cyprus-Moscow) paths. It is found that the quasi-period of MUF variations ranges from 20 min to several hours in spring 2002. The absolute value of the MUF varied in the range from 0.2 to 2 MHz. We show that variations in distance-frequency characteristics of HF signals propagated over the long-distance latitudinal path are strongly affected by quasi-periodic disturbances being the ionospheric response to acoustic-gravity waves excited by the terminator.

  6. A fast-settling frequency-presetting PLL frequency synthesizer with process variation compensation and spur reduction

    NASA Astrophysics Data System (ADS)

    Xiaozhou, Yan; Xiaofei, Kuang; Nanjian, Wu

    2009-04-01

    This paper proposes a fast-settling frequency-presetting PLL frequency synthesizer. A mixed-signal VCO and a digital processor are developed to accurately preset the frequency of VCO and greatly reduce the settling time. An auxiliary tuning loop is introduced in order to reduce reference spur caused by leakage current. The digital processor can automatically compensate presetting frequency variation with process and temperature, and control the operation of the auxiliary tuning loop. A 1.2 GHz integer-N synthesizer with 1 MHz reference input was implemented in a 0.18 μm process. The measured results demonstrate that the typical settling time of the synthesizer is less than 3 μs, and the phase noise is -108 dBc/Hz@ 1MHz. The reference spur is -52 dBc.

  7. High Contrast Imaging with Spitzer: Constraining the Frequency of Giant Planets out to 1000 au Separations

    NASA Astrophysics Data System (ADS)

    Durkan, Stephen; Janson, Markus; Carson, Joseph C.

    2016-06-01

    We report results of a re-analysis of archival Spitzer IRAC direct imaging surveys encompassing a variety of nearby stars. Our sample is generated from the combined observations of 73 young stars (median age, distance, spectral type = 85 Myr, 23.3 pc, G5) and 48 known exoplanet host stars with unconstrained ages (median distance, spectral type = 22.6 pc, G5). While the small size of Spitzer provides a lower resolution than 8 m class AO-assisted ground-based telescopes, which have been used for constraining the frequency of 0.5-13 M J planets at separations of 10-102 au, its exquisite infrared sensitivity provides the ability to place unmatched constraints on the planetary populations at wider separations. Here we apply sophisticated high-contrast techniques to our sample in order to remove the stellar point-spread function and to open up sensitivity to planetary mass companions down to 5″ separations. This enables sensitivity to 0.5-13 M J planets at physical separations on the order of 102-103 au, allowing us to probe a parameter space that has not previously been systematically explored to any similar degree of sensitivity. Based on a color and proper motion analysis, we do not record any planetary detections. Exploiting this enhanced survey sensitivity, employing Monte Carlo simulations with a Bayesian approach, and assuming a mass distribution of {dn}/{dm}\\propto {m}-1.31, we constrain (at 95% confidence) a population of 0.5-13 M J planets at separations of 100-1000 au with an upper frequency limit of 9%.

  8. System identification through nonstationary data using Time-Frequency Blind Source Separation

    NASA Astrophysics Data System (ADS)

    Guo, Yanlin; Kareem, Ahsan

    2016-06-01

    Classical output-only system identification (SI) methods are based on the assumption of stationarity of the system response. However, measured response of buildings and bridges is usually non-stationary due to strong winds (e.g. typhoon, and thunder storm etc.), earthquakes and time-varying vehicle motions. Accordingly, the response data may have time-varying frequency contents and/or overlapping of modal frequencies due to non-stationary colored excitation. This renders traditional methods problematic for modal separation and identification. To address these challenges, a new SI technique based on Time-Frequency Blind Source Separation (TFBSS) is proposed. By selectively utilizing "effective" information in local regions of the time-frequency plane, where only one mode contributes to energy, the proposed technique can successfully identify mode shapes and recover modal responses from the non-stationary response where the traditional SI methods often encounter difficulties. This technique can also handle response with closely spaced modes which is a well-known challenge for the identification of large-scale structures. Based on the separated modal responses, frequency and damping can be easily identified using SI methods based on a single degree of freedom (SDOF) system. In addition to the exclusive advantage of handling non-stationary data and closely spaced modes, the proposed technique also benefits from the absence of the end effects and low sensitivity to noise in modal separation. The efficacy of the proposed technique is demonstrated using several simulation based studies, and compared to the popular Second-Order Blind Identification (SOBI) scheme. It is also noted that even some non-stationary response data can be analyzed by the stationary method SOBI. This paper also delineates non-stationary cases where SOBI and the proposed scheme perform comparably and highlights cases where the proposed approach is more advantageous. Finally, the performance of the

  9. Variation in the resting frequency of Rhinolophus pusillus in Mainland China: Effect of climate and implications for conservation

    PubMed Central

    Jiang, Tinglei; Metzner, Walter; You, Yuyan; Liu, Sen; Lu, Guanjun; Li, Shi; Wang, Lei; Feng, Jiang

    2010-01-01

    This study describes variation patterns in the constant frequency of echolocation calls emitted at rest and when not flying (“resting frequency” RF) of the least horseshoe bat, Rhinolophus pusillus, on a broad geographical scale and in response to local climatic variables. Significant differences in RF were observed among populations throughout the species range in Mainland China, and this variation was positively and significantly related to climate conditions, especially environmental humidity, but the variability was only weakly associated with geographical distance. Sex dimorphism in the RF of R. pusillus may imply that female and male might keep their frequencies within a narrow range for sex recognition. Moreover, bats adjusted resting frequency to humidity, which may imply partitioning diet by prey size or the influence of rainfall noise. The results indicate that bats adjust echolocation call frequency to adapt to environmental conditions. Therefore, environmental selection shape the diversity of echolocation call structure of R. pusillus in geographically separated populations, and conservation efforts should focus on changes in local climate and effects of environmental noise. PMID:20968390

  10. Low-Frequency Flow Oscillations on Stalled Wings Exhibiting Cellular Separation Topology

    NASA Astrophysics Data System (ADS)

    Disotell, Kevin James

    One of the most pervasive threats to aircraft controllability is wing stall, a condition associated with loss of lift due to separation of air flow from the wing surface at high angles of attack. A recognized need for improved upset recovery training in extended-envelope flight simulators is a physical understanding of the post-stall aerodynamic environment, particularly key flow phenomena which influence the vehicle trajectory. Large-scale flow structures known as stall cells, which scale with the wing chord and are spatially-periodic along the span, have been previously observed on post-stall airfoils with trailing-edge separation present. Despite extensive documentation of stall cells in the literature, the physical mechanisms behind their formation and evolution have proven to be elusive. The undertaken study has sought to characterize the inherently turbulent separated flow existing above the wing surface with cell formation present. In particular, the question of how the unsteady separated flow may interact with the wing to produce time-averaged cellular surface patterns is considered. Time-resolved, two-component particle image velocimetry measurements were acquired at the plane of symmetry of a single stall cell formed on an extruded NACA 0015 airfoil model at chord Reynolds number of 560,000 to obtain insight into the time-dependent flow structure. The evolution of flow unsteadiness was analyzed over a static angle-of-attack range covering the narrow post-stall regime in which stall cells have been observed. Spectral analysis of velocity fields acquired near the stall angle confirmed a low-frequency flow oscillation previously detected in pointwise surface measurements by Yon and Katz (1998), corresponding to a Strouhal number of 0.042 based on frontal projected chord height. Probability density functions of the streamwise velocity component were used to estimate the convective speed of this mode at approximately half the free-stream velocity, in agreement

  11. Effects of Oscillation Frequency and Amplitude on Separation in an Unsteady Turbulent Flow.

    DTIC Science & Technology

    1980-09-01

    Effects of Oscillation Frequency and Amplitude on Separation in an Unsteady Turbulent Flow by Martin Fox Lieutenant, United States Navy B.S.A.E., Auburn...L a 0.- I III 00 0N 0 N7 IN %0i On enNn ODv ’ -D CO~ i ’ 00 0 w N C N C 70 C "𔃻 > IJ 0 . 4 ".1. 40 NNN n ) ii ’ itii 3’. vi 4et 04 D1t IN O-io -- 1

  12. Gaussian variational equations for osculating elements of an arbitrary separable reference orbit.

    NASA Technical Reports Server (NTRS)

    Vinti, J. P.

    1973-01-01

    Lagrange-type equations are often used in planetary theory and sometimes in satellite theory. The equations express the variation of osculating Keplerian elements in terms of derivatives of a disturbing function or a perturbing potential. When the perturbing force is derivable from a potential, it is possible to convert the Lagrange-type equations to another form. This form, usually, attributed to Gauss, contains the perturbing forces instead of the derivatives of the potential. The case of an arbitrary separable reference orbit is discussed together with a lemma, a Keplerian check, and questions of the applicability of the equations to the spheroidal method.

  13. Mixed variational potentials and inherent symmetries of the Cahn–Hilliard theory of diffusive phase separation

    PubMed Central

    Miehe, C.; Hildebrand, F. E.; Böger, L.

    2014-01-01

    This work shows that the Cahn–Hilliard theory of diffusive phase separation is related to an intrinsic mixed variational principle that determines the rate of concentration and the chemical potential. The principle characterizes a canonically compact model structure, where the two balances involved for the species content and microforce appear as the Euler equations of a variational statement. The existence of the variational principle underlines an inherent symmetry in the two-field representation of the Cahn–Hilliard theory. This can be exploited in the numerical implementation by the construction of time- and space-discrete incremental potentials, which fully determine the update problems of typical time-stepping procedures. The mixed variational principles provide the most fundamental approach to the finite-element solution of the Cahn–Hilliard equation based on low-order basis functions, leading to monolithic symmetric algebraic systems of iterative update procedures based on a linearization of the nonlinear problem. They induce in a natural format the choice of symmetric solvers for Newton-type iterative updates, providing a speed-up and reduction of data storage when compared with non-symmetric implementations. In this sense, the potentials developed are believed to be fundamental ingredients to a deeper understanding of the Cahn–Hilliard theory. PMID:24711722

  14. Rapid variations in fluid chemistry constrain hydrothermal phase separation at the Main Endeavour Field

    NASA Astrophysics Data System (ADS)

    Love, Brooke; Lilley, Marvin; Butterfield, David; Olson, Eric; Larson, Benjamin

    2017-02-01

    Previous work at the Main Endeavour Field (MEF) has shown that chloride concentration in high-temperature vent fluids has not exceeded 510 mmol/kg (94% of seawater), which is consistent with brine condensation and loss at depth, followed by upward flow of a vapor phase toward the seafloor. Magmatic and seismic events have been shown to affect fluid temperature and composition and these effects help narrow the possibilities for sub-surface processes. However, chloride-temperature data alone are insufficient to determine details of phase separation in the upflow zone. Here we use variation in chloride and gas content in a set of fluid samples collected over several days from one sulfide chimney structure in the MEF to constrain processes of mixing and phase separation. The combination of gas (primarily magmatic CO2 and seawater-derived Ar) and chloride data, indicate that neither variation in the amount of brine lost, nor mixing of the vapor phase produced at depth with variable quantities of (i) brine or (ii) altered gas rich seawater that has not undergone phase separation, can explain the co-variation of gas and chloride content. The gas-chloride data require additional phase separation of the ascending vapor-like fluid. Mixing and gas partitioning calculations show that near-critical temperature and pressure conditions can produce the fluid compositions observed at Sully vent as a vapor-liquid conjugate pair or as vapor-liquid pair with some remixing, and that the gas partition coefficients implied agree with theoretically predicted values.Plain Language SummaryWhen the chemistry of fluids from deep sea hot springs changes over a short time span, it allows us to narrow down the conditions and processes that created those fluids. This gives us a better idea what is happening under the seafloor where the water is interacting with hot rocks and minerals, boiling, and taking on the character it will have when it emerges at</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvE..93d2314S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvE..93d2314S"><span>Collective <span class="hlt">frequency</span> <span class="hlt">variation</span> in network synchronization and reverse PageRank</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Skardal, Per Sebastian; Taylor, Dane; Sun, Jie; Arenas, Alex</p> <p>2016-04-01</p> <p>A wide range of natural and engineered phenomena rely on large networks of interacting units to reach a dynamical consensus state where the system collectively operates. Here we study the dynamics of self-organizing systems and show that for generic directed networks the collective <span class="hlt">frequency</span> of the ensemble is not the same as the mean of the individuals' natural <span class="hlt">frequencies</span>. Specifically, we show that the collective <span class="hlt">frequency</span> equals a weighted average of the natural <span class="hlt">frequencies</span>, where the weights are given by an outflow centrality measure that is equivalent to a reverse PageRank centrality. Our findings uncover an intricate dependence of the collective <span class="hlt">frequency</span> on both the structural directedness and dynamical heterogeneity of the network, and also reveal an unexplored connection between synchronization and PageRank, which opens the possibility of applying PageRank optimization to synchronization. Finally, we demonstrate the presence of collective <span class="hlt">frequency</span> <span class="hlt">variation</span> in real-world networks by considering the UK and Scandinavian power grids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030112522','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030112522"><span><span class="hlt">Frequency</span> Reuse, Cell <span class="hlt">Separation</span>, and Capacity Analysis of VHF Digital Link Mode 3 TDMA</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shamma, Mohammed A.; Nguyen, Thanh C.; Apaza, Rafael D.</p> <p>2003-01-01</p> <p>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 <span class="hlt">frequency</span> 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 <span class="hlt">frequency</span> reuse; cell <span class="hlt">separation</span> 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 <span class="hlt">frequency</span> reuse factor is a crucial parameter for capacity estimation. Formulation of this <span class="hlt">frequency</span> 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 <span class="hlt">separation</span> of Co-Channel cells is computed for most of the <span class="hlt">Frequency</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SMaS...25e5008M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SMaS...25e5008M"><span>Detection of sudden structural damage using blind source <span class="hlt">separation</span> and time-<span class="hlt">frequency</span> approaches</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morovati, V.; Kazemi, M. T.</p> <p>2016-05-01</p> <p>Seismic signal processing is one of the most reliable methods of detecting the structural damage during earthquakes. In this paper, the use of the hybrid method of blind source <span class="hlt">separation</span> (BSS) and time-<span class="hlt">frequency</span> analysis (TFA) is explored to detect the changes in the structural response data. The combination of the BSS and TFA is applied to the seismic signals due to the non-stationary nature of them. Firstly, the second-order blind identification technique is used to decompose the response signal of structural vibration into modal coordinate signals which will be mono-components for TFA. Then each mono-component signal is analyzed to extract instantaneous <span class="hlt">frequency</span> of structure. Numerical simulations and a real-world seismic-excited structure with time-varying <span class="hlt">frequencies</span> show the accuracy and robustness of the developed algorithm. TFA of extracted sources shows that used method can be successfully applied to structural damage detection. The results also demonstrate that the combined method can be used to identify the time instant of structural damage occurrence more sharply and effectively than by the use of TFA alone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15478432','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15478432"><span>Auditory stream segregation in monkey auditory cortex: effects of <span class="hlt">frequency</span> <span class="hlt">separation</span>, presentation rate, and tone duration.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fishman, Yonatan I; Arezzo, Joseph C; Steinschneider, Mitchell</p> <p>2004-09-01</p> <p>Auditory stream segregation refers to the organization of sequential sounds into "perceptual streams" reflecting individual environmental sound sources. In the present study, sequences of alternating high and low tones, "...ABAB...," similar to those used in psychoacoustic experiments on stream segregation, were presented to awake monkeys while neural activity was recorded in primary auditory cortex (A1). Tone <span class="hlt">frequency</span> <span class="hlt">separation</span> (AF), tone presentation rate (PR), and tone duration (TD) were systematically varied to examine whether neural responses correlate with effects of these variables on perceptual stream segregation. "A" tones were fixed at the best <span class="hlt">frequency</span> of the recording site, while "B" tones were displaced in <span class="hlt">frequency</span> from "A" tones by an amount = delta F. As PR increased, "B" tone responses decreased in amplitude to a greater extent than "A" tone responses, yielding neural response patterns dominated by "A" tone responses occurring at half the alternation rate. Increasing TD facilitated the differential attenuation of "B" tone responses. These findings parallel psychoacoustic data and suggest a physiological model of stream segregation whereby increasing delta F, PR, or TD enhances spatial differentiation of "A" tone and "B" tone responses along the tonotopic map in A1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004ASAJ..116.1656F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004ASAJ..116.1656F"><span>Auditory stream segregation in monkey auditory cortex: effects of <span class="hlt">frequency</span> <span class="hlt">separation</span>, presentation rate, and tone duration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fishman, Yonatan I.; Arezzo, Joseph C.; Steinschneider, Mitchell</p> <p>2004-09-01</p> <p>Auditory stream segregation refers to the organization of sequential sounds into ``perceptual streams'' reflecting individual environmental sound sources. In the present study, sequences of alternating high and low tones, ``...ABAB...,'' similar to those used in psychoacoustic experiments on stream segregation, were presented to awake monkeys while neural activity was recorded in primary auditory cortex (A1). Tone <span class="hlt">frequency</span> <span class="hlt">separation</span> (ΔF), tone presentation rate (PR), and tone duration (TD) were systematically varied to examine whether neural responses correlate with effects of these variables on perceptual stream segregation. ``A'' tones were fixed at the best <span class="hlt">frequency</span> of the recording site, while ``B'' tones were displaced in <span class="hlt">frequency</span> from ``A'' tones by an amount=ΔF. As PR increased, ``B'' tone responses decreased in amplitude to a greater extent than ``A'' tone responses, yielding neural response patterns dominated by ``A'' tone responses occurring at half the alternation rate. Increasing TD facilitated the differential attenuation of ``B'' tone responses. These findings parallel psychoacoustic data and suggest a physiological model of stream segregation whereby increasing ΔF, PR, or TD enhances spatial differentiation of ``A'' tone and ``B'' tone responses along the tonotopic map in A1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JaJAP..52kNM07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JaJAP..52kNM07L"><span>Tailoring Surface Properties of Polymeric <span class="hlt">Separators</span> for Lithium-Ion Batteries by 13.56 MHz Radio-<span class="hlt">Frequency</span> Plasma Glow Discharge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, Chia-Han; Juang, Ruey-Shin; Tsai, Ching-Yuan; Huang, Chun</p> <p>2013-11-01</p> <p>The hydrophilic surface modification of the polymeric <span class="hlt">separator</span> is achieved by low-pressure 13.56 MHz radio-<span class="hlt">frequency</span> Ar and He gas plasma treatments. The changes in surface hydrophilicity and surface free energy were examined by static contact angle analysis. The static water contact angle of the plasma-modified polymeric <span class="hlt">separator</span> particularly decreased with the increase in treatment time. An obvious increase in the surface energy of polymeric <span class="hlt">separators</span> owing to the crosslinking by activated species of inert gases effect of monatomic-gas-plasma treatments was also observed. Optical emission spectroscopy was carried out to analyze the chemical species generated after Ar and He gas plasma treatments. The <span class="hlt">variations</span> in the surface morphology and chemical structure of the polymeric <span class="hlt">separators</span> were confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS) measurements. XPS analysis showed significantly higher surface concentrations of oxygen functional groups for monatomic-gas-plasma-modified polymeric <span class="hlt">separator</span> surfaces than for the unmodified polymeric <span class="hlt">separator</span> surface. The experimental results show the important role of chemical species in the interaction between Ar and He gas plasmas and the polymeric <span class="hlt">separator</span> surface, which can be controlled by surface modification to tailor the hydrophilicity of the polymeric <span class="hlt">separator</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_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" 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_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</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="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24740903','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24740903"><span>Negative <span class="hlt">frequency</span>-dependent preferences and <span class="hlt">variation</span> in male facial hair.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Janif, Zinnia J; Brooks, Robert C; Dixson, Barnaby J</p> <p>2014-01-01</p> <p>Negative <span class="hlt">frequency</span>-dependent sexual selection maintains striking polymorphisms in secondary sexual traits in several animal species. Here, we test whether <span class="hlt">frequency</span> of beardedness modulates perceived attractiveness of men's facial hair, a secondary sexual trait subject to considerable cultural <span class="hlt">variation</span>. We first showed participants a suite of faces, within which we manipulated the <span class="hlt">frequency</span> of beard thicknesses and then measured preferences for four standard levels of beardedness. Women and men judged heavy stubble and full beards more attractive when presented in treatments where beards were rare than when they were common, with intermediate preferences when intermediate <span class="hlt">frequencies</span> of beardedness were presented. Likewise, clean-shaven faces were least attractive when clean-shaven faces were most common and more attractive when rare. This pattern in preferences is consistent with negative <span class="hlt">frequency</span>-dependent selection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2007/5091/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2007/5091/"><span>Amplitude <span class="hlt">Variation</span> of Bottom Simulating Reflection with Respect to <span class="hlt">Frequency</span> - Transitional Base or Attenuation?</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lee, Myung W.</p> <p>2007-01-01</p> <p>The amplitude of a bottom simulating reflection (BSR), which occurs near the phase boundary between gas hydrate-bearing sediments and underlying gas-filled sediments, strongly depends on the <span class="hlt">frequency</span> content of a seismic signal, as well as the impedance contrast across the phase boundary. A strong-amplitude BSR, detectable in a conventional seismic profile, is a good indicator of the presence of free gas beneath the phase boundary. However, the BSR as observed in low-<span class="hlt">frequency</span> multichannel seismic data is generally difficult to identify in high-<span class="hlt">frequency</span>, single-channel seismic data. To investigate the <span class="hlt">frequency</span> dependence of BSR amplitudes, single-channel seismic data acquired with an air gun source at Blake Ridge, which is located off the shore of South Carolina, were analyzed in the <span class="hlt">frequency</span> range of 10-240 Hz. The <span class="hlt">frequency</span>-dependent impedance contrast caused by the velocity dispersion in partially gas saturated sediments is important to accurately analyze BSR amplitude. Analysis indicates that seismic attenuation of gas hydrate-bearing sediments, velocity dispersion, and a transitional base all contribute to the <span class="hlt">frequency</span>-dependent BSR amplitude <span class="hlt">variation</span> in the <span class="hlt">frequency</span> range of 10-500 Hz. When velocity dispersion is incorporated into the BSR amplitude analysis, the <span class="hlt">frequency</span>-dependent BSR amplitude at Blake Ridge can be explained with gas hydrate-bearing sediments having a quality factor of about 250 and a transitional base with a thickness of about 1 meter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24728188','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24728188"><span>No large-effect low-<span class="hlt">frequency</span> coding <span class="hlt">variation</span> found for myocardial infarction.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Holmen, Oddgeir L; Zhang, He; Zhou, Wei; Schmidt, Ellen; Hovelson, Daniel H; Langhammer, Arnulf; Løchen, Maja-Lisa; Ganesh, Santhi K; Mathiesen, Ellisiv B; Vatten, Lars; Platou, Carl; Wilsgaard, Tom; Chen, Jin; Skorpen, Frank; Dalen, Håvard; Boehnke, Michael; Abecasis, Goncalo R; Njølstad, Inger; Hveem, Kristian; Willer, Cristen J</p> <p>2014-09-01</p> <p>Genome-wide association studies have identified variants, primarily common, that are associated with coronary artery disease or myocardial infarction (MI), but have not tested the majority of the low <span class="hlt">frequency</span> and rare <span class="hlt">variation</span> in the genome. We explored the hypothesis that previously untested low <span class="hlt">frequency</span> (1-5% minor allele <span class="hlt">frequency</span>) and rare (<1% minor allele <span class="hlt">frequency</span>) coding variants are associated with MI. We genotyped 2906 MI cases and 6738 non-MI controls from Norway using the Illumina HumanExome Beadchip, allowing for direct genotyping of 85 972 polymorphic coding variants as well as 48 known GWAS SNPs. We followed-up 34 coding variants in an additional 2350 MI cases and 2318 controls from Norway. We evaluated exome array coverage in a subset of these samples using whole exome sequencing (N = 151). The exome array provided successful genotyping for an estimated 72.5% of Norwegian loss-of-function or missense variants with <span class="hlt">frequency</span> >1% and 66.2% of variants <1% <span class="hlt">frequency</span> observed more than once. Despite 80% power in the two-stage study (N = 14 312) to detect association with low-<span class="hlt">frequency</span> variants with high effect sizes [odds ratio (OR) >1.86 and >1.36 for 1 and 5% <span class="hlt">frequency</span>, respectively], we did not identify any novel genes or single variants that reached significance. This suggests that low-<span class="hlt">frequency</span> coding variants with large effect sizes (OR >2) may not exist for MI. Larger sample sizes may identify coding variants with more moderate effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850054906&hterms=behavior+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbehavior%2Banalysis','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850054906&hterms=behavior+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbehavior%2Banalysis"><span>Analysis of all-<span class="hlt">frequency</span> <span class="hlt">variational</span> behavior of the Kirchhoff approximation for a classic surface-scattering model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bird, J. F.</p> <p>1985-01-01</p> <p>In testing a stochastic <span class="hlt">variational</span> principle at high <span class="hlt">frequencies</span> by using a Kirchhoffean trial function in an idealized model for surface scattering - a randomly embossed plane - we have found not only the predicted high-<span class="hlt">frequency</span> improvement but also an unexpected low-<span class="hlt">frequency</span> improvement in the calculated scattering amplitudes. To investigate systematically the all-<span class="hlt">frequency</span> <span class="hlt">variational</span> behavior, we consider here the deterministic one-boss case - Rayleigh's classic model whose exact solution is available for comparison - over all wavelengths, polarizations, and configurations of incidence and scattering. We examine analytically in particular the long-wave limit of the <span class="hlt">variational</span>-Kirchhoff amplitudes; the results demonstrate improvements in both wavelength and angle depedence for horizontal (TM) polarization and some <span class="hlt">variational</span> improvements for vertical (TE) polarization. This low-<span class="hlt">frequency</span> behavior in tandem with the foreseen high-<span class="hlt">frequency</span> improvement leads to good <span class="hlt">variational</span>-Kirchhoff results through the intermediate resonance-<span class="hlt">frequency</span> regime for this model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012GeoJI.189.1611C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012GeoJI.189.1611C"><span>Implementation of elastic reverse-time migration using wavefield <span class="hlt">separation</span> in the <span class="hlt">frequency</span> domain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chung, Wookeen; Pyun, Sukjoon; Bae, Ho Seuk; Shin, Changsoo; Marfurt, Kurt J.</p> <p>2012-06-01</p> <p>Considerable effort has been devoted to the migration of multicomponent data in elastic media with wavefield <span class="hlt">separation</span> techniques being the most successful. Most of this work has been carried out in the time domain. In this paper, we formulate a multicomponent migration technique in the <span class="hlt">frequency</span> domain. Reverse-time migration can be viewed as the zero-lag cross-correlation between virtual source and back-propagated wavefields. Cross-correlating the Helmholtz decomposed wavefields rather than directly correlating the vector displacement fields results in sharper, more interpretable images, contaminated by fewer crosstalk artefacts. The end products are <span class="hlt">separate</span> P and S wave (and if desired, PS and SP) migration images. We test our migration algorithm on synthetic seismic data generated using the SEG/EAGE salt-dome, Overthrust and Marmousi-2 models. We correctly image the location and shape of the target zone for oil exploration using these data sets. Furthermore, we demonstrate that our new migration technique provides good images even when the initial velocity model is only approximate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4481908','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4481908"><span><span class="hlt">Separation</span> of Radio-<span class="hlt">Frequency</span> Sources and Localization of Partial Discharges in Noisy Environments</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Robles, Guillermo; Fresno, José Manuel; Martínez-Tarifa, Juan Manuel</p> <p>2015-01-01</p> <p>The detection of partial discharges (PD) can help in early-warning detection systems to protect critical assets in power systems. The radio-<span class="hlt">frequency</span> emission of these events can be measured with antennas even when the equipment is in service which reduces dramatically the maintenance costs and favours the implementation of condition-based monitoring systems. The drawback of these type of measurements is the difficulty of having a reference signal to study the events in a classical phase-resolved partial discharge pattern (PRPD). Therefore, in open-air substations and overhead lines where interferences from radio and TV broadcasting and mobile communications are important sources of noise and other pulsed interferences from rectifiers or inverters can be present, it is difficult to identify whether there is partial discharges activity or not. This paper proposes a robust method to <span class="hlt">separate</span> the events captured with the antennas, identify which of them are partial discharges and localize the piece of equipment that is having problems. The <span class="hlt">separation</span> is done with power ratio (PR) maps based on the spectral characteristics of the signal and the identification of the type of event is done localizing the source with an array of four antennas. Several classical methods to calculate the time differences of arrival (TDOA) of the emission to the antennas have been tested, and the localization is done using particle swarm optimization (PSO) to minimize a distance function. PMID:25923935</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25923935','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25923935"><span><span class="hlt">Separation</span> of radio-<span class="hlt">frequency</span> sources and localization of partial discharges in noisy environments.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Robles, Guillermo; Fresno, José Manuel; Martínez-Tarifa, Juan Manuel</p> <p>2015-04-27</p> <p>The detection of partial discharges (PD) can help in early-warning detection systems to protect critical assets in power systems. The radio-<span class="hlt">frequency</span> emission of these events can be measured with antennas even when the equipment is in service which reduces dramatically the maintenance costs and favours the implementation of condition-based monitoring systems. The drawback of these type of measurements is the difficulty of having a reference signal to study the events in a classical phase-resolved partial discharge pattern (PRPD). Therefore, in open-air substations and overhead lines where interferences from radio and TV broadcasting and mobile communications are important sources of noise and other pulsed interferences from rectifiers or inverters can be present, it is difficult to identify whether there is partial discharges activity or not. This paper proposes a robust method to <span class="hlt">separate</span> the events captured with the antennas, identify which of them are partial discharges and localize the piece of equipment that is having problems. The <span class="hlt">separation</span> is done with power ratio (PR) maps based on the spectral characteristics of the signal and the identification of the type of event is done localizing the source with an array of four antennas. Several classical methods to calculate the time differences of arrival (TDOA) of the emission to the antennas have been tested, and the localization is done using particle swarm optimization (PSO) to minimize a distance function.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/867546','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/867546"><span>Systems for controlling the intensity <span class="hlt">variations</span> in a laser beam and for <span class="hlt">frequency</span> conversion thereof</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Skupsky, Stanley; Craxton, R. Stephen; Soures, John</p> <p>1990-01-01</p> <p>In order to control the intensity of a laser beam so that its intensity varies uniformly and provides uniform illumination of a target, such as a laser fusion target, a broad bandwidth laser pulse is spectrally dispersed spatially so that the <span class="hlt">frequency</span> components thereof are spread apart. A disperser (grating) provides an output beam which varies spatially in wavelength in at least one direction transverse to the direction of propagation of the beam. Temporal spread (time delay) across the beam is corrected by using a phase delay device (a time delay compensation echelon). The dispersed beam may be amplified with laser amplifiers and <span class="hlt">frequency</span> converted (doubled, tripled or quadrupled in <span class="hlt">frequency</span>) with nonlinear optical elements (birefringent crystals). The spectral <span class="hlt">variation</span> across the beam is compensated by varying the angle of incidence on one of the crystals with respect to the crystal optical axis utilizing a lens which diverges the beam. Another lens after the <span class="hlt">frequency</span> converter may be used to recollimate the beam. The <span class="hlt">frequency</span> converted beam is recombined so that portions of different <span class="hlt">frequency</span> interfere and, unlike interference between waves of the same wavelength, there results an intensity pattern with rapid temoral oscillations which average out rapidly in time thereby producing uniform illumination on target. A distributed phase plate (also known as a random phase mask), through which the spectrally dispersed beam is passed and then focused on a target, is used to provide the interference pattern which becomes nearly modulation free and uniform in intensity in the direction of the spectral <span class="hlt">variation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7159875','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/7159875"><span>Systems for controlling the intensity <span class="hlt">variations</span> in a laser beam and for <span class="hlt">frequency</span> conversion thereof</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Skupsky, S.; Craxton, R.S.; Soures, J.</p> <p>1990-10-02</p> <p>In order to control the intensity of a laser beam so that its intensity varies uniformly and provides uniform illumination of a target, such as a laser fusion target, a broad bandwidth laser pulse is spectrally dispersed spatially so that the <span class="hlt">frequency</span> components thereof are spread apart. A disperser (grating) provides an output beam which varies spatially in wavelength in at least one direction transverse to the direction of propagation of the beam. Temporal spread (time delay) across the beam is corrected by using a phase delay device (a time delay compensation echelon). The dispersed beam may be amplified with laser amplifiers and <span class="hlt">frequency</span> converted (doubled, tripled or quadrupled in <span class="hlt">frequency</span>) with nonlinear optical elements (birefringent crystals). The spectral <span class="hlt">variation</span> across the beam is compensated by varying the angle of incidence on one of the crystals with respect to the crystal optical axis utilizing a lens which diverges the beam. Another lens after the <span class="hlt">frequency</span> converter may be used to recollimate the beam. The <span class="hlt">frequency</span> converted beam is recombined so that portions of different <span class="hlt">frequency</span> interfere and, unlike interference between waves of the same wavelength, there results an intensity pattern with rapid temporal oscillations which average out rapidly in time thereby producing uniform illumination on target. A distributed phase plate (also known as a random phase mask), through which the spectrally dispersed beam is passed and then focused on a target, is used to provide the interference pattern which becomes nearly modulation free and uniform in intensity in the direction of the spectral <span class="hlt">variation</span>. 16 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MNRAS.464.4777H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MNRAS.464.4777H"><span>Parametrizing the time <span class="hlt">variation</span> of the `surface term' of stellar p-mode <span class="hlt">frequencies</span>: application to helioseismic data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Howe, R.; Basu, S.; Davies, G. R.; Ball, W. H.; Chaplin, W. J.; Elsworth, Y.; Komm, R.</p> <p>2017-02-01</p> <p>The solar-cycle <span class="hlt">variation</span> of acoustic mode <span class="hlt">frequencies</span> has a <span class="hlt">frequency</span> dependence related to the inverse mode inertia. The discrepancy between model predictions and measured oscillation <span class="hlt">frequencies</span> for solar and solar-type stellar acoustic modes includes a significant <span class="hlt">frequency</span>-dependent term known as the surface term, which is also related to the inverse mode inertia. We parametrize both the surface term and the <span class="hlt">frequency</span> <span class="hlt">variations</span> for low-degree solar data from Birmingham Solar-Oscillations Network (BiSON) and medium-degree data from the Global Oscillations Network Group (GONG) using the mode inertia together with cubic and inverse <span class="hlt">frequency</span> terms. We find that for the central <span class="hlt">frequency</span> of rotationally split multiplets, the cubic term dominates both the average surface term and the temporal <span class="hlt">variation</span>, but for the medium-degree case, the inverse term improves the fit to the temporal <span class="hlt">variation</span>. We also examine the <span class="hlt">variation</span> of the even-order splitting coefficients for the medium-degree data and find that, as for the central <span class="hlt">frequency</span>, the latitude-dependent <span class="hlt">frequency</span> <span class="hlt">variation</span>, which reflects the changing latitudinal distribution of magnetic activity over the solar cycle, can be described by the combination of a cubic and an inverse function of <span class="hlt">frequency</span> scaled by inverse mode inertia. The results suggest that this simple parametrization could be used to assess the activity-related <span class="hlt">frequency</span> <span class="hlt">variation</span> in solar-like asteroseismic targets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27207643','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27207643"><span>In situ cardiac perfusion reveals interspecific <span class="hlt">variation</span> of intraventricular flow <span class="hlt">separation</span> in reptiles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Joyce, William; Axelsson, Michael; Altimiras, Jordi; Wang, Tobias</p> <p>2016-07-15</p> <p>The ventricles of non-crocodilian reptiles are incompletely divided and provide an opportunity for mixing of oxygen-poor blood and oxygen-rich blood (intracardiac shunting). However, both cardiac morphology and in vivo shunting patterns exhibit considerable interspecific <span class="hlt">variation</span> within reptiles. In the present study, we develop an in situ double-perfused heart approach to characterise the propensity and capacity for shunting in five reptile species: the turtle Trachemys scripta, the rock python Python sebae, the yellow anaconda Eunectes notaeus, the varanid lizard Varanus exanthematicus and the bearded dragon Pogona vitticeps To simulate changes in vascular bed resistance, pulmonary and systemic afterloads were independently manipulated and changes in blood flow distribution amongst the central outflow tracts were monitored. As previously demonstrated in Burmese pythons, rock pythons and varanid lizards exhibited pronounced intraventricular flow <span class="hlt">separation</span>. As pulmonary or systemic afterload was raised, flow in the respective circulation decreased. However, flow in the other circulation, where afterload was constant, remained stable. This correlates with the convergent evolution of intraventricular pressure <span class="hlt">separation</span> and the large intraventricular muscular ridge, which compartmentalises the ventricle, in these species. Conversely, in the three other species, the pulmonary and systemic flows were strongly mutually dependent, such that the decrease in pulmonary flow in response to elevated pulmonary afterload resulted in redistribution of perfusate to the systemic circuit (and vice versa). Thus, in these species, the muscular ridge appeared labile and blood could readily transverse the intraventricular cava. We conclude that relatively minor structural differences between non-crocodilian reptiles result in the fundamental changes in cardiac function. Further, our study emphasises that functionally similar intracardiac flow <span class="hlt">separation</span> evolved independently in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920068598&hterms=Ice+Age&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DIce%2BAge','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920068598&hterms=Ice+Age&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DIce%2BAge"><span><span class="hlt">Frequency</span> <span class="hlt">variations</span> of the earth's obliquity and the 100-kyr ice-age cycles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Liu, Han-Shou</p> <p>1992-01-01</p> <p>Changes in the earth's climate are induced by <span class="hlt">variations</span> in the earth's orbital parameters which modulate the seasonal distribution of solar radiation. Periodicities in the geological climate record with cycles of 100, 41, and 23 kyr have been linked with changes in obliquity, eccentricity, and precession of the equinoxes. The effect of <span class="hlt">variations</span> of eccentricity during a 100 kyr period is weak relative to the signals from obliquity and precession <span class="hlt">variations</span> and it may therefore be expected that the 100 kyr signal in the climate record would be of low intensity. However, this signal dominates the climate record and internal nonlinear processes within the climate system have previously been proposed to account for this fact. The author shows that <span class="hlt">variations</span> in the <span class="hlt">frequency</span> of the obliquity cycle can give rise to strong 100-kyr forcing of climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19197906','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19197906"><span>Dual <span class="hlt">frequency</span> dielectrophoresis with interdigitated sidewall electrodes for microfluidic flow-through <span class="hlt">separation</span> of beads and cells.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Lisen; Lu, Jente; Marchenko, Steven A; Monuki, Edwin S; Flanagan, Lisa A; Lee, Abraham P</p> <p>2009-03-01</p> <p>This paper presents a novel design and <span class="hlt">separation</span> strategy for lateral flow-through <span class="hlt">separation</span> of cells/particles in microfluidics by dual <span class="hlt">frequency</span> coupled dielectrophoresis (DEP) forces enabled by vertical interdigitated electrodes embedded in the channel sidewalls. Unlike field-flow-fractionation-DEP <span class="hlt">separations</span> in microfluidics, which utilize planar electrodes on the microchannel floor to generate a DEP force to balance the gravitational force and <span class="hlt">separate</span> objects at different height locations, lateral <span class="hlt">separation</span> is enabled by sidewall interdigitated electrodes that are used to generate non-uniform electric fields and balanced DEP forces along the width of the microchannel. In the current design, two <span class="hlt">separate</span> AC electric fields are applied to two sets of independent interdigitated electrode arrays fabricated in the sidewalls of the microchannel to generate differential DEP forces that act on the cells/particles flowing through. Individual particles (cells or beads) will experience DEP forces differently due to the difference in their dielectric properties. The balance of the differential DEP forces from the electrode arrays will position dissimilar particles at distinct equilibrium planes across the width of the channel. When coupled with fluid flow, this results in lateral <span class="hlt">separation</span> along the width of the microchannel and the <span class="hlt">separated</span> particles can thus be automatically directed into branched channel outlets leading to different reservoirs for downstream processing. In this paper, we present the design and analysis of lateral <span class="hlt">separation</span> enabled by dual <span class="hlt">frequency</span> coupled DEP, and cell/bead and cell/cell <span class="hlt">separations</span> are demonstrated with this lateral <span class="hlt">separation</span> strategy. With vertical interdigitated electrodes on the sidewall, the height of the microchannel can be increased without losing the electric field strength in contrast to other multiple <span class="hlt">frequency</span> DEP devices with planar electrodes. As a result, populations of cells can be <span class="hlt">separated</span> simultaneously</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JCoPh.324...44W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JCoPh.324...44W"><span><span class="hlt">Frequency</span>-independent approach to calculate physical optics radiations with the quadratic concave phase <span class="hlt">variations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Yu Mao; Teng, Si Jia</p> <p>2016-11-01</p> <p>In this work, we develop the numerical steepest descent path (NSDP) method to calculate the physical optics (PO) radiations with the quadratic concave phase <span class="hlt">variations</span>. With the surface integral equation method, the physical optics (PO) scattered fields are formulated and further reduced to the surface integrals. The high <span class="hlt">frequency</span> physical critical points contributions, including the stationary phase points, the boundary resonance points and the vertex points are comprehensively studied via the proposed NSDP method. The key contributions of this work are twofold. One is that together with the PO integrals taking the quadratic parabolic and hyperbolic phase terms, this work makes the NSDP theory be complete for treating the PO integrals with quadratic phase <span class="hlt">variations</span>. Another is that, in order to illustrate the transition effect of the high <span class="hlt">frequency</span> physical critical points, in this work, we consider and further extend the NSDP method to calculate the PO integrals with the coalescence of the high <span class="hlt">frequency</span> critical points. Numerical results for the highly oscillatory PO integral with the coalescence of the critical points are given to verify the efficiency of the proposed NSDP method. The NSDP method could achieve the <span class="hlt">frequency</span> independent computational workload and error controllable accuracy in all the numerical experiments, especially for the case of the coalescence of the high <span class="hlt">frequency</span> critical points.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4406052','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4406052"><span>Top down and bottom up selection drives <span class="hlt">variations</span> in <span class="hlt">frequency</span> and form of a visual signal</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yeh, Chien-Wei; Blamires, Sean J.; Liao, Chen-Pan; Tso, I.-Min</p> <p>2015-01-01</p> <p>The <span class="hlt">frequency</span> and form of visual signals can be shaped by selection from predators, prey or both. When a signal simultaneously attracts predators and prey, selection may favour a strategy that minimizes risks while attracting prey. Accordingly, varying the <span class="hlt">frequency</span> and form of the silken decorations added to their web may be a way that Argiope spiders minimize predation while attracting prey. Nonetheless, the role of extraneous factors renders the influences of top down and bottom up selection on decoration <span class="hlt">frequency</span> and form <span class="hlt">variation</span> difficult to discern. Here we used dummy spiders and decorations to simulate four possible strategies that the spider Argiope aemula may choose and measured the prey and predator attraction consequences for each in the field. The strategy of decorating at a high <span class="hlt">frequency</span> with a variable form attracted the most prey, while that of decorating at a high <span class="hlt">frequency</span> with a fixed form attracted the most predators. These results suggest that mitigating the cost of attracting predators while maintaining prey attraction drives the use of <span class="hlt">variation</span> in decoration form by many Argiope spp. when decorating frequently. Our study highlights the importance of considering top-down and bottom up selection pressure when devising evolutionary ecology experiments. PMID:25828030</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ChPhB..25h5201Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ChPhB..25h5201Z"><span>Theoretical analysis of the EAST 4-strap ion cyclotron range of <span class="hlt">frequency</span> antenna with <span class="hlt">variational</span> theory</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Jia-Hui; Zhang, Xin-Jun; Zhao, Yan-Ping; Qin, Cheng-Ming; Chen, Zhao; Yang, Lei; Wang, Jian-Hua</p> <p>2016-08-01</p> <p>A <span class="hlt">variational</span> principle code which can calculate self-consistently currents on the conductors is used to assess the coupling characteristic of the EAST 4-strap ion cyclotron range of <span class="hlt">frequency</span> (ICRF) antenna. Taking into account two layers of antenna conductors without lateral frame but with slab geometry, the antenna impedances as a function of <span class="hlt">frequency</span> and the structure of RF field excited inside the plasma in various phasing cases are discussed in this paper. Project supported by the National Magnetic Confinement Fusion Science Program, China (Grant No. 2015GB101001) and the National Natural Science Foundation of China (Grant Nos. 11375236 and 11375235).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4367342','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4367342"><span>High <span class="hlt">Frequency</span> <span class="hlt">Variations</span> of Earth Rotation Parameters from GPS and GLONASS Observations</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wei, Erhu; Jin, Shuanggen; Wan, Lihua; Liu, Wenjie; Yang, Yali; Hu, Zhenghong</p> <p>2015-01-01</p> <p>The Earth's rotation undergoes changes with the influence of geophysical factors, such as Earth's surface fluid mass redistribution of the atmosphere, ocean and hydrology. However, <span class="hlt">variations</span> of Earth Rotation Parameters (ERP) are still not well understood, particularly the short-period <span class="hlt">variations</span> (e.g., diurnal and semi-diurnal <span class="hlt">variations</span>) and their causes. In this paper, the hourly time series of Earth Rotation Parameters are estimated using Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), and combining GPS and GLONASS data collected from nearly 80 sites from 1 November 2012 to 10 April 2014. These new observations with combining different satellite systems can help to decorrelate orbit biases and ERP, which improve estimation of ERP. The high <span class="hlt">frequency</span> <span class="hlt">variations</span> of ERP are analyzed using a de-trending method. The maximum of total diurnal and semidiurnal <span class="hlt">variations</span> are within one milli-arcseconds (mas) in Polar Motion (PM) and 0.5 milli-seconds (ms) in UT1-UTC. The semidiurnal and diurnal <span class="hlt">variations</span> are mainly related to the ocean tides. Furthermore, the impacts of satellite orbit and time interval used to determinate ERP on the amplitudes of tidal terms are analyzed. We obtain some small terms that are not described in the ocean tide model of the IERS Conventions 2010, which may be caused by the strategies and models we used or the signal noises as well as artifacts. In addition, there are also small differences on the amplitudes between our results and IERS convention. This might be a result of other geophysical excitations, such as the high-<span class="hlt">frequency</span> <span class="hlt">variations</span> in atmospheric angular momentum (AAM) and hydrological angular momentum (HAM), which needs more detailed analysis with more geophysical data in the future. PMID:25635416</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25635416','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25635416"><span>High <span class="hlt">frequency</span> <span class="hlt">variations</span> of Earth Rotation Parameters from GPS and GLONASS observations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wei, Erhu; Jin, Shuanggen; Wan, Lihua; Liu, Wenjie; Yang, Yali; Hu, Zhenghong</p> <p>2015-01-28</p> <p>The Earth's rotation undergoes changes with the influence of geophysical factors, such as Earth's surface fluid mass redistribution of the atmosphere, ocean and hydrology. However, <span class="hlt">variations</span> of Earth Rotation Parameters (ERP) are still not well understood, particularly the short-period <span class="hlt">variations</span> (e.g., diurnal and semi-diurnal <span class="hlt">variations</span>) and their causes. In this paper, the hourly time series of Earth Rotation Parameters are estimated using Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), and combining GPS and GLONASS data collected from nearly 80 sites from 1 November 2012 to 10 April 2014. These new observations with combining different satellite systems can help to decorrelate orbit biases and ERP, which improve estimation of ERP. The high <span class="hlt">frequency</span> <span class="hlt">variations</span> of ERP are analyzed using a de-trending method. The maximum of total diurnal and semidiurnal <span class="hlt">variations</span> are within one milli-arcseconds (mas) in Polar Motion (PM) and 0.5 milli-seconds (ms) in UT1-UTC. The semidiurnal and diurnal <span class="hlt">variations</span> are mainly related to the ocean tides. Furthermore, the impacts of satellite orbit and time interval used to determinate ERP on the amplitudes of tidal terms are analyzed. We obtain some small terms that are not described in the ocean tide model of the IERS Conventions 2010, which may be caused by the strategies and models we used or the signal noises as well as artifacts. In addition, there are also small differences on the amplitudes between our results and IERS convention. This might be a result of other geophysical excitations, such as the high-<span class="hlt">frequency</span> <span class="hlt">variations</span> in atmospheric angular momentum (AAM) and hydrological angular momentum (HAM), which needs more detailed analysis with more geophysical data in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1202657','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1202657"><span>Natural Selection VS. Random Drift: Evidence from Temporal <span class="hlt">Variation</span> in Allele <span class="hlt">Frequencies</span> in Nature</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mueller, Laurence D.; Barr, Lorraine G.; Ayala, Francisco J.</p> <p>1985-01-01</p> <p>We have obtained monthly samples of two species, Drosophila pseudoobscura and Drosophila persimilis, in a natural population from Napa County, California. In each species, about 300 genes have been assayed by electrophoresis for each of seven enzyme loci in each monthly sample from March 1972 to June 1975. Using statistical methods developed for the purpose, we have examined whether the allele <span class="hlt">frequencies</span> at different loci vary in a correlated fashion. The methods used do not detect natural selection when it is deterministic (e.g., overdominance or directional selection), but only when alleles at different loci vary simultaneously in response to the same environmental <span class="hlt">variations</span>. Moreover, only relatively large fitness differences (of the order of 15%) are detectable. We have found strong evidence of correlated allele <span class="hlt">frequency</span> <span class="hlt">variation</span> in 13–20% of the cases examined. We interpret this as evidence that natural selection plays a major role in the evolution of protein polymorphisms in nature. PMID:4054608</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PPCF...59d5013B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PPCF...59d5013B"><span><span class="hlt">Variational</span> approach to low-<span class="hlt">frequency</span> kinetic-MHD in the current coupling scheme</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burby, Joshua W.; Tronci, Cesare</p> <p>2017-04-01</p> <p>Hybrid kinetic-MHD models describe the interaction of an MHD bulk fluid with an ensemble of hot particles, which obeys a kinetic equation. In this work we apply Hamilton’s <span class="hlt">variational</span> principle to formulate new current-coupling kinetic-MHD models in the low-<span class="hlt">frequency</span> approximation (i.e. large Larmor <span class="hlt">frequency</span> limit). More particularly, we formulate current-coupling schemes, in which energetic particle dynamics are expressed in either guiding center or gyrocenter coordinates. When guiding center theory is used to model the hot particles, we show how energy conservation requires corrections to the standard magnetization term. On the other hand, charge and momentum conservation in gyrokinetic-MHD lead to extra terms in the usual definition of the hot current density as well as modifications to conventional gyrocenter dynamics. All these new features arise naturally from the underlying <span class="hlt">variational</span> structure of the proposed models.</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_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" 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_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</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="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DPPCM9007T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DPPCM9007T"><span><span class="hlt">Variational</span> approach to low-<span class="hlt">frequency</span> kinetic-MHD in the current-coupling scheme</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tronci, Cesare; Burby, Joshua</p> <p>2016-10-01</p> <p>Hybrid kinetic-MHD models describe the interaction of an MHD bulk fluid with an ensemble of hot particles, which is described by a kinetic equation. When the Vlasov description is adopted for the energetic particles, different Vlasov-MHD models have been shown to lack an exact energy balance, unless non-inertial force terms are inserted in the kinetic equation. These force terms arise from fundamental approaches based on Hamiltonian and <span class="hlt">variational</span> methods. In this work we apply Hamilton's <span class="hlt">variational</span> principle to formulate new current-coupling kinetic-MHD models in the low-<span class="hlt">frequency</span> approximation (i.e. large Larmor <span class="hlt">frequency</span> limit). More particularly, we formulate current-coupling hybrid schemes, in which energetic particle dynamics are expressed in either guiding-center or gyrocenter coordinates. Financial support by the Leverhulme Trust Research Project Grant No. 2014-112 is greatly acknowledged.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010MSSP...24..567G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010MSSP...24..567G"><span>The new chirp-Wigner higher order spectra for transient signals with any known nonlinear <span class="hlt">frequency</span> <span class="hlt">variation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gelman, L.; Petrunin, I.; Komoda, J.</p> <p>2010-02-01</p> <p>The new chirp-Wigner higher order spectra (CWHOS) are proposed for transient signals with any known nonlinear polynomial <span class="hlt">variation</span> of instantaneous <span class="hlt">frequency</span>. The proposed technique is effective for nonlinearity detection for transient signals with nonlinear polynomial time <span class="hlt">variation</span> of the instantaneous <span class="hlt">frequency</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RaSc...51.1660N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RaSc...51.1660N"><span>Detection of hypervelocity impact radio <span class="hlt">frequency</span> pulses through prior constrained source <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nuttall, Andrew; Kochenderfer, Mykel; Close, Sigrid</p> <p>2016-10-01</p> <p>Hypervelocity dust impacts produce electromagnetic pulses in the radio <span class="hlt">frequency</span> (RF) spectrum that scales with impactor mass and velocity. Due to the mass acceleration limitations of ground-based facilities, detecting emissions from impacts in a laboratory setup is difficult due to their low output power. This paper presents a general probabilistic technique to perform signal excision, which was applied to synthetic and hypervelocity impact data sets. The task of excising multiple signals from a single observation of their mixtures is referred to as underdetermined blind source <span class="hlt">separation</span> (BSS). This paper introduces a framework for solving underdetermined BSS problems when there is only one observation signal by leveraging often overlooked prior information. The most probable solutions for the source signals are computed by solving an iterative constrained optimization problem that seeks to maximize the posterior probability of the system model. In the hypervelocity impact data set, the goal was to reduce the noise floor on an RF antenna by modeling and extracting exterior sources of noise. It was found that the algorithm described in this paper was able to model signals in the observation and subtract them while still maintaining the spectral and temporal content of the remaining signals. Through the use of this methodology, previously hidden impact emissions were able to be isolated and identified for further characterization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016isms.confEMF05T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016isms.confEMF05T"><span><span class="hlt">Variation</span> of CH Stretch <span class="hlt">Frequencies</span> with CH_4 Orientation in the CH_4 - F^- Complex: Multiple Resonances as Vibrational Conical Intersections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thapaliya, Bishnu P.; Perry, David S.</p> <p>2016-06-01</p> <p>In the CH_4 - F^- complex, an adiabatic <span class="hlt">separation</span> of the CH stretch <span class="hlt">frequencies</span> from the CH_4 orientational coordinates allows the calculation of the four adiabatic CH stretch surfaces. These ab initio calculations reveal (i) a large <span class="hlt">variation</span> of CH stretch <span class="hlt">frequencies</span> (> 100 wn) in the orientational space and (ii) the existence of four symmetrically equivalent sets of vibrational conical intersections (CIs). Two sets of symmetry-allowed CIs are identified in addition to the symmetry-required CIs at the front- and back-side C3v geometries. These results have implications for the evolution of excited CH vibrations in methane during its approach to a potentially reactive surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22522070','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22522070"><span>PULSAR TIMING ERRORS FROM ASYNCHRONOUS MULTI-<span class="hlt">FREQUENCY</span> SAMPLING OF DISPERSION MEASURE <span class="hlt">VARIATIONS</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lam, M. T.; Cordes, J. M.; Chatterjee, S.; Dolch, T.</p> <p>2015-03-10</p> <p>Free electrons in the interstellar medium cause <span class="hlt">frequency</span>-dependent delays in pulse arrival times due to both scattering and dispersion. Multi-<span class="hlt">frequency</span> measurements are used to estimate and remove dispersion delays. In this paper, we focus on the effect of any non-simultaneity of multi-<span class="hlt">frequency</span> observations on dispersive delay estimation and removal. Interstellar density <span class="hlt">variations</span> combined with changes in the line of sight from pulsar and observer motions cause dispersion measure (DM) <span class="hlt">variations</span> with an approximately power-law power spectrum, augmented in some cases by linear trends. We simulate time series, estimate the magnitude and statistical properties of timing errors that result from non-simultaneous observations, and derive prescriptions for data acquisition that are needed in order to achieve a specified timing precision. For nearby, highly stable pulsars, measurements need to be simultaneous to within about one day in order for the timing error from asynchronous DM correction to be less than about 10 ns. We discuss how timing precision improves when increasing the number of dual-<span class="hlt">frequency</span> observations used in DM estimation for a given epoch. For a Kolmogorov wavenumber spectrum, we find about a factor of two improvement in precision timing when increasing from two to three observations but diminishing returns thereafter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000GeoJI.142..889L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000GeoJI.142..889L"><span>Using geomagnetic secular <span class="hlt">variation</span> to <span class="hlt">separate</span> remanent and induced sources of the crustal magnetic field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lesur, Vincent; Gubbins, David</p> <p>2000-09-01</p> <p>Magnetic fields originating from magnetized crustal rocks dominate the geomagnetic spectrum at wavelengths of 0.1-100km. It is not known whether the magnetization is predominantly induced or remanent, and static surveys cannot discriminate between the two. Long-running magnetic observatories offer a chance, in principle, of <span class="hlt">separating</span> the two sources because secular <span class="hlt">variation</span> leads to a change in the main inducing field, which in turn causes a change in the induced part of the short-wavelength crustal field. We first argue that the induced crustal field, bI(t), is linearly related to the local core field, B(t), through a symmetric, trace-free matrix A: bI(t)=AB(t). We then subtract a core field model from the observatory annual means and invert the residuals for three components of the remanent field, bR(t), and the five independent elements of A. Applying the method to 20 European observatories, all of which have recorded for more than 50 years, shows that the most difficult task is to distinguish bR from the steady part of bI. However, for nine observatories a time-dependent induced field fits the data better than a steady remanent field at the 99 per cent confidence level, suggesting the presence of a significant induced component to the magnetization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19686983','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19686983"><span>Cyclic <span class="hlt">variations</span> of high-<span class="hlt">frequency</span> ultrasonic backscattering from blood under pulsatile flow.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huang, Chih-Chung</p> <p>2009-08-01</p> <p>It was shown previously that ultrasonic scattering from whole blood varies during the flow cycle under pulsatile flow both in vitro and in vivo. It has been postulated that the cyclic <span class="hlt">variations</span> of the backscattering signal are associated with red blood cell (RBC) aggregation in flowing whole blood. To obtain a better understanding of the relationship between blood backscattering and RBC aggregation behavior for pulsatile flowing blood, the present study used high-<span class="hlt">frequency</span> ultrasound to characterize blood properties. The backscattering signals from both whole blood and an RBC suspension at different peak flow velocities (from 10 to 30 cm/s) and hematocrits (20% and 40%) under pulsatile flow (stroke rate of 20 beats/min) were measured with 3 single-element transducers at <span class="hlt">frequencies</span> of 10, 35, and 50 MHz in a mock flow loop. To avoid the <span class="hlt">frequency</span> response problem of a Doppler flowmeter, the integrated backscatter (IB) and flow velocity as functions of time were calculated directly using RF signals from flowing blood. The experimental results showed that cyclic <span class="hlt">variations</span> of the IB curve were clearly observed at a low flow velocity and a hematocrit of 40% when using 50 MHz ultrasound, and that these <span class="hlt">variations</span> became weaker as the peak flow velocity increased. However, these cyclic <span class="hlt">variations</span> were detected only at 10 cm/s when using 10 MHz ultrasound. These results demonstrate that a high flow velocity can stop the formation of rouleaux and that a high hematocrit can promote RBC aggregation to produce cyclic <span class="hlt">variations</span> of the backscattering signal under pulsatile flow. In addition, slight cyclic <span class="hlt">variations</span> of the IB curve for an RBC suspension were observed at 35 and 50 MHz. Furthermore, the peak of the IB curve from whole blood led the peak of the velocity waveform when using high-<span class="hlt">frequency</span> ultrasound, which could be explained by the assumption that a rapid flow can promote RBC aggregation under pulsatile flow. Together, the experimental results showed that the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4822465','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4822465"><span><span class="hlt">Variation</span> in relapse <span class="hlt">frequency</span> and the transmission potential of Plasmodium vivax malaria</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>White, Michael T.; Shirreff, George; Karl, Stephan; Ghani, Azra C.; Mueller, Ivo</p> <p>2016-01-01</p> <p>There is substantial <span class="hlt">variation</span> in the relapse <span class="hlt">frequency</span> of Plasmodium vivax malaria, with fast-relapsing strains in tropical areas, and slow-relapsing strains in temperate areas with seasonal transmission. We hypothesize that much of the phenotypic diversity in P. vivax relapses arises from selection of relapse <span class="hlt">frequency</span> to optimize transmission potential in a given environment, in a process similar to the virulence trade-off hypothesis. We develop mathematical models of P. vivax transmission and calculate the basic reproduction number R0 to investigate how transmission potential varies with relapse <span class="hlt">frequency</span> and seasonality. In tropical zones with year-round transmission, transmission potential is optimized at intermediate relapse <span class="hlt">frequencies</span> of two to three months: slower-relapsing strains increase the opportunity for onward transmission to mosquitoes, but also increase the risk of being outcompeted by faster-relapsing strains. Seasonality is an important driver of relapse <span class="hlt">frequency</span> for temperate strains, with the time to first relapse predicted to be six to nine months, coinciding with the duration between seasonal transmission peaks. We predict that there is a threshold degree of seasonality, below which fast-relapsing tropical strains are selected for, and above which slow-relapsing temperate strains dominate, providing an explanation for the observed global distribution of relapse phenotypes. PMID:27030414</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27030414','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27030414"><span><span class="hlt">Variation</span> in relapse <span class="hlt">frequency</span> and the transmission potential of Plasmodium vivax malaria.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>White, Michael T; Shirreff, George; Karl, Stephan; Ghani, Azra C; Mueller, Ivo</p> <p>2016-03-30</p> <p>There is substantial <span class="hlt">variation</span> in the relapse <span class="hlt">frequency</span> of Plasmodium vivax malaria, with fast-relapsing strains in tropical areas, and slow-relapsing strains in temperate areas with seasonal transmission. We hypothesize that much of the phenotypic diversity in P. vivax relapses arises from selection of relapse <span class="hlt">frequency</span> to optimize transmission potential in a given environment, in a process similar to the virulence trade-off hypothesis. We develop mathematical models of P. vivax transmission and calculate the basic reproduction number R0 to investigate how transmission potential varies with relapse <span class="hlt">frequency</span> and seasonality. In tropical zones with year-round transmission, transmission potential is optimized at intermediate relapse <span class="hlt">frequencies</span> of two to three months: slower-relapsing strains increase the opportunity for onward transmission to mosquitoes, but also increase the risk of being outcompeted by faster-relapsing strains. Seasonality is an important driver of relapse <span class="hlt">frequency</span> for temperate strains, with the time to first relapse predicted to be six to nine months, coinciding with the duration between seasonal transmission peaks. We predict that there is a threshold degree of seasonality, below which fast-relapsing tropical strains are selected for, and above which slow-relapsing temperate strains dominate, providing an explanation for the observed global distribution of relapse phenotypes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MNRAS.464.4408S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MNRAS.464.4408S"><span>A thorough analysis of the short- and mid-term activity-related <span class="hlt">variations</span> in the solar acoustic <span class="hlt">frequencies</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Santos, A. R. G.; Cunha, M. S.; Avelino, P. P.; Chaplin, W. J.; Campante, T. L.</p> <p>2017-02-01</p> <p>The <span class="hlt">frequencies</span> of the solar acoustic oscillations vary over the activity cycle. The <span class="hlt">variations</span> in other activity proxies are found to be well correlated with the <span class="hlt">variations</span> in the acoustic <span class="hlt">frequencies</span>. However, each proxy has a slightly different time behaviour. Our goal is to characterize the differences between the time behaviour of the <span class="hlt">frequency</span> shifts and of two other activity proxies, namely the area covered by sunspots and the 10.7-cm flux. We define a new observable that is particularly sensitive to the short-term <span class="hlt">frequency</span> <span class="hlt">variations</span>. We then compare the observable when computed from model <span class="hlt">frequency</span> shifts and from observed <span class="hlt">frequency</span> shifts obtained with the Global Oscillation Network Group (GONG) for cycle 23. Our analysis shows that on the shortest time-scales, the <span class="hlt">variations</span> in the <span class="hlt">frequency</span> shifts seen in the GONG observations are strongly correlated with the <span class="hlt">variations</span> in the area covered by sunspots. However, a significant loss of correlation is still found. We verify that the times when the <span class="hlt">frequency</span> shifts and the sunspot area do not vary in a similar way tend to coincide with the times of the maxima of the quasi-biennial <span class="hlt">variations</span> seen in the solar seismic data. A similar analysis of the relation between the 10.7-cm flux and the <span class="hlt">frequency</span> shifts reveals that the short-time <span class="hlt">variations</span> in the <span class="hlt">frequency</span> shifts follow even more closely those of the 10.7-cm flux than those of the sunspot area. However, a loss of correlation between <span class="hlt">frequency</span> shifts and 10.7-cm flux <span class="hlt">variations</span> is still found around the same times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920024126&hterms=rubidium&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Drubidium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920024126&hterms=rubidium&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Drubidium"><span>Measuring <span class="hlt">frequency</span> changes due to microwave power <span class="hlt">variations</span> as a function of C-field setting in a rubidium <span class="hlt">frequency</span> standard</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sarosy, E. B.; Johnson, Walter A.; Karuza, Sarunas K.; Voit, Frank J.</p> <p>1992-01-01</p> <p>It has been shown in previous studies that in some cesium <span class="hlt">frequency</span> standards there exist certain C-field settings that minimize <span class="hlt">frequency</span> changes that are due to <span class="hlt">variations</span> in the microwave power. In order to determine whether similar results could be obtained with rubidium (Rb) <span class="hlt">frequency</span> standards (clocks), we performed a similar study, using a completely automated measurement system, on a commercial Rb standard. From our measurements we found that changing the microwave power to the filter cell resulted in significant changes in <span class="hlt">frequency</span>, and that the magnitude of these <span class="hlt">frequency</span> changes at low C-field levels went to zero and decreased as the C-field was increased.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AtmRe.100..391B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AtmRe.100..391B"><span>Regional and yearly <span class="hlt">variations</span> of hail <span class="hlt">frequency</span> and intensity in France</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berthet, C.; Dessens, J.; Sanchez, J. L.</p> <p>2011-06-01</p> <p>In addition to the ground seeding hail prevention project, the Association Nationale d'Etude et de Lutte contre les Fléaux Atmosphériques (ANELFA) operates hailpad networks in four of the most hailed regions of France: Atlantic, Pyrenean, Central and Mediterranean. During the past 22 years of continuous measurements, more than five thousand point hailfalls have been recorded at 922 stations (mean annual value) installed in a 66,500 km² area. At the scale of a region and of a hail season, hail is found to be the product of two nearly independent parameters, the <span class="hlt">frequency</span> and the mean intensity of hailfalls. The <span class="hlt">frequency</span> is highest in the Pyrenean region, while the intensity is highest both in the Pyrenean and Central regions. This can be explained, for the <span class="hlt">frequency</span>, by the proximity of Spain, and, for the intensity, by the mean hailstone size distributions which are different in the continental and maritime regions. The time <span class="hlt">variations</span> and trends of hail during the 1989-2009 period are computed from the data at 457 stations which never changed during this period. The annual <span class="hlt">frequency</span> is subject to cyclic <span class="hlt">variations</span>, while the yearly mean intensity is affected by irregular severe hail events. The <span class="hlt">frequency</span> did not change significantly during the period, while the intensity increased by 70%. The mean monthly distribution of hail is bimodal, with two maximums in May and July, suggesting that two types of meteorological conditions are at the origin of hailstorms. April and May are solely responsible for the mean hail increase observed during the period. A computation of the year-to-year correlation between hail intensity and mean minimum surface temperature for each month suggests that the large hail increase in April and May is at least partially due to the observed concomitant increase in temperature, and then may be a consequence of global warning.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/3351147','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/3351147"><span>Atrial signal <span class="hlt">variations</span> and pacemaker malsensing during exercise: a study in the time and <span class="hlt">frequency</span> domain.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fröhlig, G; Schwerdt, H; Schieffer, H; Bette, L</p> <p>1988-04-01</p> <p>To give some explanation for atrial malsensing in dual chamber pacing that occurs only during exercise, atrial electrograms from 33 patients were telemetrically recorded and analyzed in both the time and <span class="hlt">frequency</span> domains. During exercise, an overall decrease from 6.4 +/- 1.9 to 5.6 +/- 1.9 mV (-11%) in the atrial signal amplitude was noted. Despite considerable variability among patients, marked changes occurred in 15 patients whose signals diminished by 11 to 49%. Slew rates showed a similar decrease from 1.35 +/- 0.45 to 1.18 +/- 0.45 V/s (-10.8%), with individual changes of as much as -51%. Signal attenuation in the time domain correlated well with <span class="hlt">frequency</span> data, exhibiting a highly significant reduction of signal energy between 25 and 105 Hz. However, spectral distribution changed from rest to exercise, with a relative increase of signal energy in the range between 5 and 25 Hz and a decrease at higher <span class="hlt">frequencies</span>. Individual changes differed widely when low (15 to 65 Hz) and high (65 to 115 Hz) <span class="hlt">frequencies</span> were compared, but in a group of 11 patients signal attenuation in the high <span class="hlt">frequency</span> band was more pronounced (-45%) than in the low <span class="hlt">frequency</span> band (-23%). The clinical impact of the change in <span class="hlt">frequency</span> distribution during ergometry was visualized by computer simulation of two different (low and high bandpass) filters. Although in individual patients, both characteristics may be favorable with respect to atrial sensing, it was observed in 11 patients that high pass filtering attenuates signal amplitudes by 10 to 24% in excess of the <span class="hlt">variation</span> without filtering.(ABSTRACT TRUNCATED AT 250 WORDS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20377573','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20377573"><span>Does infectious disease cause global <span class="hlt">variation</span> in the <span class="hlt">frequency</span> of intrastate armed conflict and civil war?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Letendre, Kenneth; Fincher, Corey L; Thornhill, Randy</p> <p>2010-08-01</p> <p>Geographic and cross-national <span class="hlt">variation</span> in the <span class="hlt">frequency</span> of intrastate armed conflict and civil war is a subject of great interest. Previous theory on this <span class="hlt">variation</span> has focused on the influence on human behaviour of climate, resource competition, national wealth, and cultural characteristics. We present the parasite-stress model of intrastate conflict, which unites previous work on the correlates of intrastate conflict by linking <span class="hlt">frequency</span> of the outbreak of such conflict, including civil war, to the intensity of infectious disease across countries of the world. High intensity of infectious disease leads to the emergence of xenophobic and ethnocentric cultural norms. These cultures suffer greater poverty and deprivation due to the morbidity and mortality caused by disease, and as a result of decreased investment in public health and welfare. Resource competition among xenophobic and ethnocentric groups within a nation leads to increased <span class="hlt">frequency</span> of civil war. We present support for the parasite-stress model with regression analyses. We find support for a direct effect of infectious disease on intrastate armed conflict, and support for an indirect effect of infectious disease on the incidence of civil war via its negative effect on national wealth. We consider the entanglements of feedback of conflict into further reduced wealth and increased incidence of disease, and discuss implications for international warfare and global patterns of wealth and imperialism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70144383','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70144383"><span>Ecological drivers of <span class="hlt">variation</span> in tool-use <span class="hlt">frequency</span> across sea otter populations</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fujii, Jessica A; Ralls, Katherine; Tinker, M. Tim</p> <p>2015-01-01</p> <p>Sea otters are well-known tool users, employing objects such as rocks or shells to break open hard-shelled invertebrate prey. However, little is known about how the <span class="hlt">frequency</span> of tool use varies among sea otter populations and the factors that drive these differences. We examined 17 years of observational data on prey capture and tool use from 8 sea otter populations ranging from southern California to the Aleutian Islands in Alaska. There were significant differences in the diets of these populations as well as <span class="hlt">variation</span> in the <span class="hlt">frequency</span> of tool use. Sea otters at Amchitka Island, Alaska, used tools on less than 1% of dives that resulted in the capture of prey compared with approximately 16% in Monterey, California. The percentage of individuals in the population that used tools ranged from 10% to 93%. In all populations, marine snails and thick-shelled bivalves were most likely to be associated with tool use, whereas soft-bodied prey items such as worms and sea stars were the least likely. The probability that a tool would be used on a given prey type varied across populations. The morphology of the prey item being handled and the prevalence of various types of prey in local diets were major ecological drivers of tool use: together they accounted for about 64% of the <span class="hlt">variation</span> in tool-use <span class="hlt">frequency</span> among populations. The remaining <span class="hlt">variation</span> may be related to changes in the relative costs and benefits to an individual otter of learning to use tools effectively under differing ecological circumstances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E1450K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E1450K"><span>The <span class="hlt">variations</span> of ionosphere critical <span class="hlt">frequency</span> of E layer over Chumphon during solar cycle 24</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kenpankho, Prasert; Tsugawa, Takuya; Supnithi, Pornchai; Wongcharoen, Poramintra</p> <p></p> <p>The values of the critical <span class="hlt">frequency</span> of the ionospheric E layer, foE, obtained at Chumphon ionospheric observatory station (geographic 99.37 E, 10.72 N, 3 dip), Thailand, during the year 2007-2012, have been used to investigate the <span class="hlt">variations</span> of foE over the geomagnetic equatorial region during the solar cycle 24. The investigation, including <span class="hlt">variations</span> with local time, day, seasons and solar cycle, is in agreement with the observations. A comparison between the observation data and International Reference Ionosphere (IRI) 2012 model has also been made. The IRI 2012 model underestimates foE especially during the period of 7-11 am and after 6 pm for each day and all seasons. Combining with previous investigations, we suggest that underestimation of ionospheric foE by IRI 2012 model is very helpful for the correction of IRI model in an equatorial Asia region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5157949','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5157949"><span>Mutation Rate <span class="hlt">Variation</span> is a Primary Determinant of the Distribution of Allele <span class="hlt">Frequencies</span> in Humans</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Pritchard, Jonathan K.</p> <p>2016-01-01</p> <p>The site <span class="hlt">frequency</span> spectrum (SFS) has long been used to study demographic history and natural selection. Here, we extend this summary by examining the SFS conditional on the alleles found at the same site in other species. We refer to this extension as the “phylogenetically-conditioned SFS” or cSFS. Using recent large-sample data from the Exome Aggregation Consortium (ExAC), combined with primate genome sequences, we find that human variants that occurred independently in closely related primate lineages are at higher <span class="hlt">frequencies</span> in humans than variants with parallel substitutions in more distant primates. We show that this effect is largely due to sites with elevated mutation rates causing significant departures from the widely-used infinite sites mutation model. Our analysis also suggests substantial <span class="hlt">variation</span> in mutation rates even among mutations involving the same nucleotide changes. In summary, we show that variable mutation rates are key determinants of the SFS in humans. PMID:27977673</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080007433','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080007433"><span>Active noise control using noise source having adaptive resonant <span class="hlt">frequency</span> tuning through stiffness <span class="hlt">variation</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pla, Frederic G. (Inventor); Rajiyah, Harindra (Inventor); Renshaw, Anthony A. (Inventor); Hedeen, Robert A. (Inventor)</p> <p>1995-01-01</p> <p>A noise source for an aircraft engine active noise cancellation system in which the resonant <span class="hlt">frequency</span> of a noise radiating element is tuned to permit noise cancellation over a wide range of <span class="hlt">frequencies</span>. The resonant <span class="hlt">frequency</span> of the noise radiating element is tuned by a plurality of force transmitting mechanisms which contact the noise radiating element. Each one of the force transmitting mechanisms includes an expandable element and a spring in contact with the noise radiating element so that excitation of the element varies the spring force applied to the noise radiating element. The elements are actuated by a controller which receives input of a signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage <span class="hlt">frequency</span> of the engine's fan. In response, the controller determines a control signal which is sent to the elements and causes the spring force applied to the noise radiating element to be varied. The force transmitting mechanisms can be arranged to either produce bending or linear stiffness <span class="hlt">variations</span> in the noise radiating element.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MsT..........5G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MsT..........5G"><span>Water tunnel experiments on span-wise <span class="hlt">variation</span> of laminar <span class="hlt">separation</span> bubbles for swept and unswept wings using particle image velocimetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gilbert, Jordan</p> <p></p> <p>An inverted airfoil mounted above a flat plate was used to create laminar <span class="hlt">separation</span> bubbles on a flat plate in water tunnel experiments at low Reynolds numbers. Boundary layer suction ensured that the flow remained attached to the wing. Two-dimensional PIV measurements were used to qualitatively and quantitatively characterize the spanwise bubble <span class="hlt">variation</span> on an unswept wing and on the same wing featuring a 22 degree sweep. The <span class="hlt">separation</span> bubbles were recorded at varied span-wise locations in a 31.5 cm wide region of the flow. The limitations of this measurement region were dictated by the focal length of the laser optic used for PIV measurements. The straight wing exhibited approximately uniform time averaged <span class="hlt">separation</span> positions across the span of the wing. The reattachment locations varied only slightly which was expected due to the transition to turbulent flow before reattachment. A form of bubble "breathing" was observed in the laminar <span class="hlt">separation</span> bubbles on the straight wing and is believed to have affected the mean reattachment locations for two data points recorded. The shedding <span class="hlt">frequencies</span> on the straight wing were slightly higher than those obtained from CFD simulations. The swept wing planform showed significantly more <span class="hlt">variation</span> in the mean <span class="hlt">separation</span> and reattachment locations with respect to the leading edge of the wing. There is a general trend of the <span class="hlt">separation</span> locations moving upstream in the direction of the aft leading edge. The reattachment points are shown to move downstream as the <span class="hlt">separation</span> points move upstream relative to the leading edge and visa versa, displaying an inverse relationship between the two. The bubble lengths were found to be slightly longer on the swept wing compared to the straight wing usually by about 10%. The shedding <span class="hlt">frequencies</span> on the swept wing were found to be lower than the straight wing. The quality of flow in the water tunnel may have degraded over time, showing signs of increased free stream turbulence. After data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4725738','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4725738"><span>Wolbachia in European Populations of the Invasive Pest Drosophila suzukii: Regional <span class="hlt">Variation</span> in Infection <span class="hlt">Frequencies</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>Gibert, Patricia; Martinez, Julien; Fraimout, Antoine; Jiggins, Francis; Andrieux, Thibault; Siozios, Stefanos; Anfora, Gianfranco; Miller, Wolfgang; Rota-Stabelli, Omar; Mouton, Laurence</p> <p>2016-01-01</p> <p>The invasive pest Drosophila suzukii is characterized by a specific fresh-fruit targeting behavior and has quickly become a menace for the fruit economy of newly infested North American and European regions. D. suzukii carries a strain of the endosymbiotic bacterium Wolbachia, named wSuz, which has a low infection <span class="hlt">frequency</span> and no reproductive manipulation capabilities in American populations of D. suzukii. To further understand the nature of wSuz biology and assess its utility as a tool for controlling this pest’s populations, we investigated the prevalence of Wolbachia in 23 European D. suzukii populations, and compared our results with those available in American populations. Our data showed a highly variable infection <span class="hlt">frequency</span> with a mean prevalence of 46%, which is significantly higher than the 17% found in American populations. Based on Multilocus Sequence Typing analysis, a single wSuz strain was diagnosed in all European populations of D. suzukii. In agreement with American data, we found no evidence of cytoplasmic incompatibility induced by wSuz. These findings raise two questions: a) why Wolbachia is maintained in field populations of D. suzukii and b) what are the selective forces responsible for the <span class="hlt">variation</span> in prevalence within populations, particularly between European and American continents? Our results provide new insights into the D. suzukii-Wolbachia association and highlight regional <span class="hlt">variations</span> that await further investigation and that should be taken into account for using Wolbachia-based pest management programs. PMID:26809119</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_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" 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_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</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="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26809119','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26809119"><span>Wolbachia in European Populations of the Invasive Pest Drosophila suzukii: Regional <span class="hlt">Variation</span> in Infection <span class="hlt">Frequencies</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cattel, Julien; Kaur, Rupinder; Gibert, Patricia; Martinez, Julien; Fraimout, Antoine; Jiggins, Francis; Andrieux, Thibault; Siozios, Stefanos; Anfora, Gianfranco; Miller, Wolfgang; Rota-Stabelli, Omar; Mouton, Laurence</p> <p>2016-01-01</p> <p>The invasive pest Drosophila suzukii is characterized by a specific fresh-fruit targeting behavior and has quickly become a menace for the fruit economy of newly infested North American and European regions. D. suzukii carries a strain of the endosymbiotic bacterium Wolbachia, named wSuz, which has a low infection <span class="hlt">frequency</span> and no reproductive manipulation capabilities in American populations of D. suzukii. To further understand the nature of wSuz biology and assess its utility as a tool for controlling this pest's populations, we investigated the prevalence of Wolbachia in 23 European D. suzukii populations, and compared our results with those available in American populations. Our data showed a highly variable infection <span class="hlt">frequency</span> with a mean prevalence of 46%, which is significantly higher than the 17% found in American populations. Based on Multilocus Sequence Typing analysis, a single wSuz strain was diagnosed in all European populations of D. suzukii. In agreement with American data, we found no evidence of cytoplasmic incompatibility induced by wSuz. These findings raise two questions: a) why Wolbachia is maintained in field populations of D. suzukii and b) what are the selective forces responsible for the <span class="hlt">variation</span> in prevalence within populations, particularly between European and American continents? Our results provide new insights into the D. suzukii-Wolbachia association and highlight regional <span class="hlt">variations</span> that await further investigation and that should be taken into account for using Wolbachia-based pest management programs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5348505','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5348505"><span><span class="hlt">Variation</span> in the human lymphocyte sister chromatid exchange <span class="hlt">frequency</span> as a function of time: results of daily and twice-weekly sampling</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tucker, J.D.; Christensen, M.L.; Strout, C.L.; McGee, K.A.; Carrano, A.V.</p> <p>1987-01-01</p> <p>The <span class="hlt">variation</span> in lymphocyte sister chromatid exchange (SCE) <span class="hlt">frequency</span> was investigated in healthy nonsmokers who were not taking any medication. Two <span class="hlt">separate</span> studies were undertaken. In the first, blood was drawn from four women twice a week for 8 weeks. These donors recorded the onset and termination of menstruation and times of illness. In the second study, blood was obtained from two women and two men for 5 consecutive days on two <span class="hlt">separate</span> occasions initiated 14 days apart. Analysis of the mean SCE <span class="hlt">frequencies</span> in each study indicated that significant temporal <span class="hlt">variation</span> occurred in each donor, and that more <span class="hlt">variation</span> occurred in the longer study. Some of the <span class="hlt">variation</span> was found to be associated with the menstrual cycle. In the daily study, most of the <span class="hlt">variation</span> appeared to be random, but occasional day-to-day changes occurred that were greater than those expected by chance. To determine how well a single SCE sample estimated the pooled mean for each donor in each study, the authors calculated the number of samples that encompassed that donor's pooled mean within 1 or more standard errors. For both studies, about 75% of the samples encompassed the pooled mean within 2 standard errors. An analysis of high-<span class="hlt">frequency</span> cells (HFCs) was also undertaken. The results for each study indicate that the proportion of HFCs, compared with the use of Fisher's Exact test, is significantly more constant than the means, which were compared by using the t-test. These results coupled with our previous work suggest that HFC analysis may be the method of choice when analyzing data from human population studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9932806','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9932806"><span>High-<span class="hlt">frequency</span> alternating-crossed-field gel electrophoresis with neutral or slightly charged interpenetrating networks to improve DNA <span class="hlt">separation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boyd, B M; Prausnitz, J M; Blanch, H W</p> <p>1998-12-01</p> <p>Toward improving DNA <span class="hlt">separations</span>, this work reports the effects of high-<span class="hlt">frequency</span> square-wave AC fields superimposed perpendicular to the direct current (DC) <span class="hlt">separation</span> field on DNA migration in both polyacrylamide-based interpenetrating networks (IPNs) and in agarose networks. Compared to standard polyacrylamide gels, IPNs allow the <span class="hlt">separation</span> of larger DNA (9000 bp vs. 5000 bp at 5 V/cm). In novel polyacrylamide-based IPNs, an alternating current (AC) field of 5 Hz increased the maximum DNA size <span class="hlt">separable</span>. This effect was extended to larger DNA sizes with increasing electric-field strength up to and apparently beyond the power supply-limited maximum electric-field strength of 48 V/cm. The orthogonal AC field also increased mobility. These two results combine to yield a reduction in <span class="hlt">separation</span> time of up to a factor of 20 in novel polyacrylamide-based IPNs. When negatively charged acrylic-acid groups were incorporated into the IPNs, the use of the AC field changed the DNA-network interaction, which altered the size dependence of DNA mobility. In agarose gels, an AC field of 50 Hz increased the size range <span class="hlt">separable</span>; however, there was no increase in DNA mobility. There was no change in size dependence of mobility in an AC field when the number of charged groups in the agarose network was increased. Based on results in the literature, possible mechanisms were examined for the effects of the AC field on DNA <span class="hlt">separation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B23F0653X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B23F0653X"><span>Hydrological niche <span class="hlt">separation</span> explains seasonal and inter-annual <span class="hlt">variations</span> of vegetation dynamics in seasonally dry tropical forests</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, X.; Medvigy, D.; Powers, J. S.; Becknell, J. M.; Guan, K.</p> <p>2015-12-01</p> <p>Despite ample water supply, vegetation dynamics are subject to seasonal water stress in large fraction of tropical forests. These seasonally dry tropical forests (SDTFs) account for over 40% of tropical forests, harbor high biodiversity, have large potential carbon sink due to forest recovery from human disturbance and also play a critical role in global carbon budget and inter-annual <span class="hlt">variations</span>. Plants in this biome display notably diverse responses to seasonal and inter-annual <span class="hlt">variations</span> of water availability, especially inter-specific <span class="hlt">variations</span> in canopy seasonality and biomass growth. Current process-based dynamic vegetation models cannot represent these diversities and are shown to perform poorly on simulating drought responses of tropical forests, calling into question of their ability to accurately simulate future changes in SDTFs. Accumulated field observations, suggest that hydrological niche <span class="hlt">separation</span> driven by coordinated plant functional traits is associated with plants' performance under drought. Yet, it remains not clear whether the physiology-level hydrological niche <span class="hlt">separation</span> can explain the ecosystem-level diversity observed in SDTFs. Here, we test the theory with a model-data fusion approach. We implemented a new plant hydrodynamic module that is able to track leaf water potential at sub-daily scale in ED2 model. We further incorporated a hydrological niche <span class="hlt">separation</span> scheme based on a meta-data analysis of key functional traits in SDTFs. Simulated ecological patterns with and without hydrological niche <span class="hlt">separation</span> were then compared with remote-sensing and long-term field observations from an SDTF site in Palo Verde, Costa Rica. Using several numerical experiments, we specifically examine the following questions: (i) Whether hydrological niche <span class="hlt">separation</span> can explain the diversity in canopy seasonality and biomass growth? (ii) How important are the yet uncertain belowground functional traits, especially root profile in determining canopy</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017OptCo.382..604W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017OptCo.382..604W"><span>Time division approach to <span class="hlt">separate</span> overlapped interference fringes of multiple pulse trains of femtosecond optical <span class="hlt">frequency</span> comb for length measurement</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wei, Dong; Aketagawa, Masato</p> <p>2017-01-01</p> <p>In this study, we attempt the <span class="hlt">separation</span> of overlapped interference fringes arising from multiple pulse trains of a femtosecond optical <span class="hlt">frequency</span> comb for length measurement. Based on an optical experiment, we test the performance of the <span class="hlt">separation</span> of two overlapped interference fringes by time division for an absolute length measurement, which is about one adjacent pulse repetition interval length. We compare our results with those of a commercial He-Ne interferometer system. The two sets of results show an agreement within 0.7 μm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A13G0313M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A13G0313M"><span>Regional <span class="hlt">frequency</span> analysis to asses wind resource spatial and temporal <span class="hlt">variations</span> in Washington State</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mortuza, M.; Demissie, D.</p> <p>2013-12-01</p> <p>According to the U.S. Department of Energy's annual wind technologies market report, the wind power capacity in the country grew from 2.5 gigawatts in early 2000 to 60 gigawatts in 2012, making it one of the largest new sources of electric capacity additions in the U.S. in recent years. With over 2.8 gigawatts of current capacity (eighth largest in the nation), Washington State plays a significant role in this rapidly increasing energy resource. To further expand and/or optimize these capacities, assessment of wind resource and its spatial and temporal <span class="hlt">variations</span> are important. However, since at-site <span class="hlt">frequency</span> analysis using meteorological data is not adequate for extending wind <span class="hlt">frequency</span> to locations with no data, longer return period, and heterogeneous topography and surface, a regional <span class="hlt">frequency</span> analysis based on L-moment method is adopted in this study to estimate regional wind speed patterns and return periods in Washington State using hourly mean wind speed data from 1979 - 2010. The analysis applies the k-means, hierarchical and self-organizing map clustering techniques to explore potential clusters or regions; statistical tests are then applied to identify homogeneous regions and appropriate probability distribution models. The result from the analysis is expected to provide essential knowledge about the areas with potential capacity of constructing wind power plants, which can also be readily extended to assist decisions on their daily operations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhFl...29c3102O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhFl...29c3102O"><span><span class="hlt">Variational</span> approach to powder-binder <span class="hlt">separation</span> in Poiseuille and Couette flows</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oh, Youngmin; Park, Dong Yong; Park, Seong Jin; Fontelos, Marco Antonio; Hwang, Hyung Ju</p> <p>2017-03-01</p> <p>To predict the time-evolution of powder <span class="hlt">separation</span> in the Phillips model, we derive an essential condition under a viscosity model for non-Newtonian fluids which considers the effects of shear rate and particle volume fraction. Under the condition, the time-evolution is independent of initial conditions, and powder <span class="hlt">separation</span> converges in time to smooth steady-states. The proposed condition also determines the existence and uniqueness of smooth steady-states and the degree of powder <span class="hlt">separation</span>. Finally, we compare the theoretical prediction for the particle volume fraction to numerical verification for the purpose of confirming our prediction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5292413','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5292413"><span>Robustness of <span class="hlt">Frequency</span> Division Technique for Online Myoelectric Pattern Recognition against Contraction-Level <span class="hlt">Variation</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>Tolooshams, Bahareh; Jiang, Ning</p> <p>2017-01-01</p> <p>Contraction-level invariant surface electromyography pattern recognition introduces the decrease of training time and decreases the limitation of clinical prostheses. This study intended to examine whether a signal pre-processing method named <span class="hlt">frequency</span> division technique (FDT) for online myoelectric pattern recognition classification is robust against contraction-level <span class="hlt">variation</span>, and whether this pre-processing method has an advantage over traditional time-domain pattern recognition techniques even in the absence of muscle contraction-level <span class="hlt">variation</span>. Eight healthy and naïve subjects performed wrist contractions during two degrees of freedom goal-oriented tasks, divided in three groups of type I, type II, and type III. The performance of these tasks, when the two different methods were used, was quantified by completion rate, completion time, throughput, efficiency, and overshoot. The traditional and the FDT method were compared in four runs, using combinations of normal or high muscle contraction level, and the traditional method or FDT. The results indicated that FDT had an advantage over traditional methods in the tested real-time myoelectric control tasks. FDT had a much better median completion rate of tasks (95%) compared to the traditional method (77.5%) among non-perfect runs, and the variability in FDT was strikingly smaller than the traditional method (p < 0.001). Moreover, the FDT method outperformed the traditional method in case of contraction-level <span class="hlt">variation</span> between the training and online control phases (p = 0. 005 for throughput in type I tasks with normal contraction level, p = 0.006 for throughput in type II tasks, and p = 0.001 for efficiency with normal contraction level of all task types). This study shows that FDT provides advantages in online myoelectric control as it introduces robustness over contraction-level <span class="hlt">variations</span>. PMID:28220147</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhyA..469..731O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhyA..469..731O"><span>A mathematical structure of the <span class="hlt">separated</span> <span class="hlt">variational</span> principles of steady states for multi-forces and multi-currents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Okada, Kanzo</p> <p>2017-03-01</p> <p><span class="hlt">Separated</span> <span class="hlt">variational</span> principles of steady states for multi-forces and multi-currents in transport phenomena were recently proposed by Suzuki (Suzuki, 2013) by extending the principle of minimum integrated entropy production for a single force found by the same author (Suzuki, 2013). On the other hand, in non-equilibrium thermodynamics, Edelen (Edelen, 1974) generalized the linear Onsager theory to those irreversible processes with significant thermodynamic forces by means of Onsager fluxes. Onsager fluxes by definition satisfy a nonlinear system of reciprocity relations, vanish in thermodynamic equilibrium, and satisfy the second law of thermodynamics. Each system of Onsager fluxes is derivable from a dissipation potential sometimes called the flux potential. This paper aims to elucidate a mathematical structure of the <span class="hlt">separated</span> <span class="hlt">variational</span> principles based on the above work of Edelen.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27085959','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27085959"><span>Effect of ultrasonic <span class="hlt">frequency</span> on <span class="hlt">separation</span> of water from heavy crude oil emulsion using ultrasonic baths.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Antes, Fabiane G; Diehl, Liange O; Pereira, Juliana S F; Guimarães, Regina C L; Guarnieri, Ricardo A; Ferreira, Bianca M S; Flores, Erico M M</p> <p>2017-03-01</p> <p>In this work, a comprehensive study was performed for the evaluation of ultrasound (US) <span class="hlt">frequency</span> for demulsification of crude oil emulsions. Experiments were performed using ultrasonic baths operating at the following <span class="hlt">frequencies</span>: 25, 35, 45, 130, 582, 862 and 1146kHz. Synthetic water-in-oil emulsions with 12%, 35% and 50% of water and medians of droplet size distribution (DSD, D(0.5)) of 5, 10 and 25μm were prepared using a heavy crude oil (API density of 19). Crude oil demulsification was achieved at <span class="hlt">frequencies</span> in the range of 25-45kHz for all tested emulsions. When <span class="hlt">frequencies</span> higher than 45kHz were applied, no changes in the characteristics of the crude oil emulsions were observed. Demulsification efficiencies of about 65% were achieved at a <span class="hlt">frequency</span> of 45kHz after 15min of US application (emulsions with original water content of 50% and D(0.5)=10μm). An important aspect is that no addition of chemical demulsifiers was performed, and the demulsification efficiency was considered high, taking into account that the results were obtained using a non-conventional crude oil. Contrary to the normal application of low-<span class="hlt">frequency</span> US that has been used for emulsification, the proposed approach seems to be a promising technology for water removal from crude oil emulsions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27814533','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27814533"><span>Temporal and spatial <span class="hlt">variations</span> in road traffic noise for different <span class="hlt">frequency</span> components in metropolitan Taichung, Taiwan.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Ven-Shing; Lo, Ei-Wen; Liang, Chih-Hsiang; Chao, Keh-Ping; Bao, Bo-Ying; Chang, Ta-Yuan</p> <p>2016-12-01</p> <p>Road traffic noise exposure has been associated with auditory and non-auditory health effects, but few studies report noise characteristics. This study determines 24-h noise levels and analyzes their <span class="hlt">frequency</span> components to investigate associations between seasons, meteorology, land-use types, and traffic. We set up 50 monitoring stations covering ten different land-use types and conducted measurements at three times of the year to obtain 24-h-average A-weighted equivalent noise levels (LAeq,24h) and <span class="hlt">frequency</span> analyses from 2013 to 2014 in Taichung, Taiwan. Information on land-use types, road parameters, traffic flow rates, and meteorological variables was also collected for analysis with the annual averages of road traffic noise and its <span class="hlt">frequency</span> components. The annual average LAeq,24h in Taichung was 66.4 ± 4.7 A-weighed decibels (dBA). Significant differences in LAeq,24h and <span class="hlt">frequency</span> components were observed between land-use types (all p-values < 0.001), but not between seasons, with the highest two noise levels of 71.2 ± 1.0 dBA and 70.0 ± 2.6 dBA measured in stream-channel and commercial areas, with the highest component being 61.4 ± 5.3 dBA at 1000 Hz. Road width, traffic flow rates, and land-use types were significantly associated with annual average LAeq,24h (all p-values < 0.050). Noise levels at 125 Hz had the highest correlation with total traffic (Spearman's coefficient = 0.795) and the highest prediction in the multiple linear regression (R(2) = 0.803; adjusted R(2) = 0.765). These findings reveal the spatial <span class="hlt">variation</span> in road traffic noise exposure in Taichung. The highest correlation and predictive capacity was observed between this <span class="hlt">variation</span> and noise levels at 125 Hz. We recommend that governmental agencies should take actions to reduce noise levels from traffic vehicles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.8603M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.8603M"><span>Regional <span class="hlt">Variations</span> in Low <span class="hlt">Frequency</span> Transport Variability of the Southern Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Makowski, Jessica; Chambers, Don</p> <p>2016-04-01</p> <p>Using ocean bottom pressure data from the Gravity Recovery and Climate Experiment (GRACE) and the ECCO2 state estimate, we estimate the variability of the low <span class="hlt">frequency</span> zonal transport in the Southern Ocean. The interannual <span class="hlt">variations</span> and trend estimates from calculated transport variability differ as the east-west averaging area and north-south boundaries change. We look at various study areas throughout the Southern Ocean, including west of the Drake Passage, in order to determine the regional variability and coherency within the Southern Ocean. We have observed a high coherency between the Southern Annular Mode (SAM) and interannual variability in the transport south of Australia, and further investigate how other regions respond to the SAM and zonally averaged Southern Hemisphere winds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGeod..90.1237M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGeod..90.1237M"><span>High-<span class="hlt">frequency</span> Earth rotation <span class="hlt">variations</span> deduced from altimetry-based ocean tides</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Madzak, Matthias; Schindelegger, Michael; Böhm, Johannes; Bosch, Wolfgang; Hagedoorn, Jan</p> <p>2016-11-01</p> <p>A model of diurnal and semi-diurnal <span class="hlt">variations</span> in Earth rotation parameters (ERP) is constructed based on altimetry-measured tidal heights from a multi-mission empirical ocean tide solution. Barotropic currents contributing to relative angular momentum changes are estimated for nine major tides in a global inversion algorithm that solves the two-dimensional momentum equations on a regular 0.5° grid with a heavily weighted continuity constraint. The influence of 19 minor tides is accounted for by linear admittance interpolation of ocean tidal angular momentum, although the assumption of smooth admittance <span class="hlt">variations</span> with <span class="hlt">frequency</span> appears to be a doubtful concept for semi-diurnal mass terms in particular. A validation of the newly derived model based on post-fit corrections to polar motion and universal time (Δ UT1) from the analysis of Very Long Baseline Interferometry (VLBI) observations shows a variance reduction for semi-diurnal Δ UT1 residuals that is significant at the 0.05 level with respect to the conventional ERP model. Improvements are also evident for the explicitly modeled K_1, Q_1, and K_2 tides in individual ERP components, but large residuals of more than 15 μ as remain at the principal lunar <span class="hlt">frequencies</span> of O_1 and M_2. We attribute these shortcomings to uncertainties in the inverted relative angular momentum changes and, to a minor extent, to violation of mass conservation in the empirical ocean tide solution. Further dedicated hydrodynamic modeling efforts of these anomalous constituents are required to meet the accuracy standards of modern space geodesy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JSV...337..218L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JSV...337..218L"><span><span class="hlt">Frequency</span> <span class="hlt">variation</span> and sensor contribution assessment: Application to an offshore platform in the South China Sea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Fushun; Li, Huajun; Wang, Weiying; Li, Wei; Wang, Bin</p> <p>2015-02-01</p> <p>In this paper, a time-<span class="hlt">frequency</span> and multiple-sensor assessment method is presented and then applied to an offshore platform in the South China Sea with the goal of providing a more suitable time duration of measured signals and evaluating each sensor's contribution to mode shapes of interest. By processing all measured signals simultaneously, a series of linear parameters are used to fit the measured signals. A moving window in overlapping steps along the time record of a non-stationary signal is used for time-<span class="hlt">frequency</span> analysis while a series of amplitude matrices are obtained for all sliced segments. These segments are then used to evaluate each sensor's contribution to <!--retain&QJ;retain-->some mode(s) of interest. Compared with the short-time Fourier transform (STFT) or <!--retain&QJ;retain-->S-transform method, the <span class="hlt">frequencies</span> used in this time-<span class="hlt">frequency</span> analysis are shared by the sensors involved so that the <span class="hlt">variations</span> in the results due to the characteristics of different sensors are avoided. In addition, the approach requires only a short-duration segment to obtain high-<span class="hlt">frequency</span> resolution, which will improve the computing efficiency of modal analysis using measured seat est data. The proposed method could also be used to estimate damping ratios and each sensor's contribution to modes of interest based on the analysis of the series of amplitude matrices; this could be used to guide the installation of sensors in field tests of offshore structures. To demonstrate the proposed method with a time-<span class="hlt">frequency</span> analysis, a numerical example of a synthesized signal with five segments, each with its owns different <span class="hlt">frequency</span> componentsincluding a relatively weaker component, is constructed; numerical results from the analysis of this example signal indicate that the approach could yield a sharper image with a good computing efficiency. The second example simulates three signals that represent multiple measurements; this example is used to study each sensor</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3210668','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3210668"><span><span class="hlt">Frequency</span>-dependent <span class="hlt">variation</span> in the two-dimensional beam pattern of an echolocating dolphin</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Starkhammar, Josefin; Moore, Patrick W.; Talmadge, Lois; Houser, Dorian S.</p> <p>2011-01-01</p> <p>Recent recordings of dolphin echolocation using a dense array of hydrophones suggest that the echolocation beam is dynamic and can at times consist of a single dominant peak, while at other times it consists of forward projected primary and secondary peaks with similar energy, partially overlapping in space and <span class="hlt">frequency</span> bandwidth. The spatial <span class="hlt">separation</span> of the peaks provides an area in front of the dolphin, where the spectral magnitude slopes drop off quickly for certain <span class="hlt">frequency</span> bands. This region is potentially used to optimize prey localization by directing the maximum pressure slope of the echolocation beam at the target, rather than the maximum pressure peak. The dolphin was able to steer the beam horizontally to a greater extent than previously described. The complex and dynamic sound field generated by the echolocating dolphin may be due to the use of two sets of phonic lips as sound sources, or an unknown complexity in the sound propagation paths or acoustic properties of the forehead tissues of the dolphin. PMID:21561965</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EJASP2012..113L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EJASP2012..113L"><span>Independent vector analysis based on overlapped cliques of variable width for <span class="hlt">frequency</span>-domain blind signal <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Intae; Jang, Gil-Jin</p> <p>2012-12-01</p> <p>A novel method is proposed to improve the performance of independent vector analysis (IVA) for blind signal <span class="hlt">separation</span> of acoustic mixtures. IVA is a <span class="hlt">frequency</span>-domain approach that successfully resolves the well-known permutation problem by applying a spherical dependency model to all pairs of <span class="hlt">frequency</span> bins. The dependency model of IVA is equivalent to a single clique in an undirected graph; a clique in graph theory is defined as a subset of vertices in which any pair of vertices is connected by an undirected edge. Therefore, IVA imposes the same amount of statistical dependency on every pair of <span class="hlt">frequency</span> bins, which may not match the characteristics of real-world signals. The proposed method allows variable amounts of statistical dependencies according to the correlation coefficients observed in real acoustic signals and, hence, enables more accurate modeling of statistical dependencies. A number of cliques constitutes the new dependency graph so that neighboring <span class="hlt">frequency</span> bins are assigned to the same clique, while distant bins are assigned to different cliques. The permutation ambiguity is resolved by overlapped <span class="hlt">frequency</span> bins between neighboring cliques. For speech signals, we observed especially strong correlations across neighboring <span class="hlt">frequency</span> bins and a decrease in these correlations with an increase in the distance between bins. The clique sizes are either fixed, or determined by the reciprocal of the mel-<span class="hlt">frequency</span> scale to impose a wider dependency on low-<span class="hlt">frequency</span> components. Experimental results showed improved performances over conventional IVA. The signal-to-interference ratio improved from 15.5 to 18.8 dB on average for seven different source locations. When we varied the clique sizes according to the observed correlations, the stability of the proposed method increased with a large number of cliques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.4035B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.4035B"><span>Demeter/ICE Experiment: Study of low <span class="hlt">frequency</span> transmitter intensity <span class="hlt">variations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boudjada, M. Y.; Moldovan, I.; Schwingenschuh, K.; Al-Haddad, E.; Biagi, P. F.; Parrot, M.</p> <p>2012-04-01</p> <p>We report on low <span class="hlt">frequency</span> (LF) transmitter signal recorded by the 'Instrument Capteur Electrique' (ICE) experiment onboard the DEMETER micro-satellite. We mainly consider the signal emitted by the Brasov broadcasting station (25.60E, 45.75N) at <span class="hlt">frequency</span> of about 153 kHz. We analyze the reception conditions of this transmitter several weeks before the occurrence of the Vrancea earthquakes, on October, 27th, 2004. Ground-based observations revealed the presence of sudden decrease of the Y-component of the magnetic field at Muntele Rosu Observatory (Romania), at about 68 km from the epicenter, as reported by Moldovan et al. (Rom. Journ. Phys., Vol. 54, Nos. 1-2, p. 249-261, Bucharest, 2009). In this contribution we attempt to check if the LF Brasov signal was also subject to similar disturbances as observed by the ground-station. We focus on the <span class="hlt">variation</span> of the LF transmitter intensity levels, several weeks before and after the Vrancea earthquake occurrence. We discuss the physical parameters which may disturb the signal reception in particular the geomagnetic activity and the signal to noise ratios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20338748','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20338748"><span>Belt <span class="hlt">separation</span> system under slat in fattening pig housing: effect of belt type and extraction <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>Alonso, F; Vázquez, J; Ovejero, I; Garcimartín, M A; Mateos, A; Sánchez, E</p> <p>2010-08-01</p> <p>The efficiency of manure <span class="hlt">separation</span> by a conveyor belt under a partially slatted floor for fattening pigs was determined for two types of belts, a flat belt with an incline of up to 6 degrees transversely and a concave belt with an incline of up to 1 degrees longitudinally. A 31.20% and 23.75% dry matter content of the solid fraction was obtained for the flat and concave belt, respectively. The flat belt was more efficient at 6 degrees than other slope angles. The residence time of the manure on the two belt types influenced the <span class="hlt">separation</span> efficiency from a live weight of 63.00 kg upwards. The quantity of residue produced with this system was reduced to 25-40% with respect to a pit system under slat. This could mean a remarkable reduction in costs of storage, transport and application of manure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ApJ...765....5D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApJ...765....5D"><span>Periodic <span class="hlt">Variations</span> in the O - C Diagrams of Five Pulsation <span class="hlt">Frequencies</span> of the DB White Dwarf EC 20058-5234</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dalessio, J.; Sullivan, D. J.; Provencal, J. L.; Shipman, H. L.; Sullivan, T.; Kilkenny, D.; Fraga, L.; Sefako, R.</p> <p>2013-03-01</p> <p><span class="hlt">Variations</span> in the pulsation arrival time of five independent pulsation <span class="hlt">frequencies</span> of the DB white dwarf EC 20058-5234 individually imitate the effects of reflex motion induced by a planet or companion but are inconsistent when considered in unison. The pulsation <span class="hlt">frequencies</span> vary periodically in a 12.9 year cycle and undergo secular changes that are inconsistent with simple neutrino plus photon-cooling models. The magnitude of the periodic and secular <span class="hlt">variations</span> increases with the period of the pulsations, possibly hinting that the corresponding physical mechanism is located near the surface of the star. The phase of the periodic <span class="hlt">variations</span> appears coupled to the sign of the secular <span class="hlt">variations</span>. The standards for pulsation-timing-based detection of planetary companions around pulsating white dwarfs, and possibly other variables such as subdwarf B stars, should be re-evaluated. The physical mechanism responsible for this surprising result may involve a redistribution of angular momentum or a magnetic cycle. Additionally, <span class="hlt">variations</span> in a supposed combination <span class="hlt">frequency</span> are shown to match the sum of the <span class="hlt">variations</span> of the parent <span class="hlt">frequencies</span> to remarkable precision, an expected but unprecedented confirmation of theoretical predictions. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the US National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22167670','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22167670"><span>PERIODIC <span class="hlt">VARIATIONS</span> IN THE O - C DIAGRAMS OF FIVE PULSATION <span class="hlt">FREQUENCIES</span> OF THE DB WHITE DWARF EC 20058-5234</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dalessio, J.; Provencal, J. L.; Shipman, H. L.; Sullivan, D. J.; Sullivan, T.; Kilkenny, D.; Fraga, L.; Sefako, R.</p> <p>2013-03-01</p> <p><span class="hlt">Variations</span> in the pulsation arrival time of five independent pulsation <span class="hlt">frequencies</span> of the DB white dwarf EC 20058-5234 individually imitate the effects of reflex motion induced by a planet or companion but are inconsistent when considered in unison. The pulsation <span class="hlt">frequencies</span> vary periodically in a 12.9 year cycle and undergo secular changes that are inconsistent with simple neutrino plus photon-cooling models. The magnitude of the periodic and secular <span class="hlt">variations</span> increases with the period of the pulsations, possibly hinting that the corresponding physical mechanism is located near the surface of the star. The phase of the periodic <span class="hlt">variations</span> appears coupled to the sign of the secular <span class="hlt">variations</span>. The standards for pulsation-timing-based detection of planetary companions around pulsating white dwarfs, and possibly other variables such as subdwarf B stars, should be re-evaluated. The physical mechanism responsible for this surprising result may involve a redistribution of angular momentum or a magnetic cycle. Additionally, <span class="hlt">variations</span> in a supposed combination <span class="hlt">frequency</span> are shown to match the sum of the <span class="hlt">variations</span> of the parent <span class="hlt">frequencies</span> to remarkable precision, an expected but unprecedented confirmation of theoretical predictions.</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_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" 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_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</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="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3971153','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3971153"><span>Maintaining acoustic communication at a cocktail party: heterospecific masking noise improves signal detection through <span class="hlt">frequency</span> <span class="hlt">separation</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>Siegert, M. E.; Römer, H.; Hartbauer, M.</p> <p>2014-01-01</p> <p>SUMMARY We examined acoustic masking in a chirping katydid species of the Mecopoda elongata complex due to interference with a sympatric Mecopoda species where males produce continuous trills at high amplitudes. <span class="hlt">Frequency</span> spectra of both calling songs range from 1 to 80 kHz; the chirper species has more energy in a narrow <span class="hlt">frequency</span> band at 2 kHz and above 40 kHz. Behaviourally, chirper males successfully phase-locked their chirps to playbacks of conspecific chirps under masking conditions at signal-to-noise ratios (SNRs) of −8 dB. After the 2 kHz band in the chirp had been equalised to the level in the masking trill, the breakdown of phase-locked synchrony occurred at a SNR of +7 dB. The remarkable receiver performance is partially mirrored in the selective response of a first-order auditory interneuron (TN1) to conspecific chirps under these masking conditions. However, the selective response is only maintained for a stimulus including the 2 kHz component, although this <span class="hlt">frequency</span> band has no influence on the unmasked TN1 response. Remarkably, the addition of masking noise at 65 dB sound pressure level (SPL) to threshold response levels of TN1 for pure tones of 2 kHz enhanced the sensitivity of the response by 10 dB. Thus, the spectral dissimilarity between masker and signal at a rather low <span class="hlt">frequency</span> appears to be of crucial importance for the ability of the chirping species to communicate under strong masking by the trilling species. We discuss the possible properties underlying the cellular/synaptic mechanisms of the ‘novelty detector’. PMID:24307713</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1462226','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1462226"><span>The tRNA-Tyr gene family of Saccharomyces cerevisiae: agents of phenotypic <span class="hlt">variation</span> and position effects on mutation <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>Ito-Harashima, Sayoko; Hartzog, Phillip E; Sinha, Himanshu; McCusker, John H</p> <p>2002-01-01</p> <p>Extensive phenotypic diversity or <span class="hlt">variation</span> exists in clonal populations of microorganisms and is thought to play a role in adaptation to novel environments. This phenotypic <span class="hlt">variation</span> or instability, which occurs by multiple mechanisms, may be a form of cellular differentiation and a stochastic means for modulating gene expression. This work dissects a case of phenotypic <span class="hlt">variation</span> in a clinically derived Saccharomyces cerevisiae strain involving a cox15 ochre mutation, which acts as a reporter. The ochre mutation reverts to sense at a low <span class="hlt">frequency</span> while tRNA-Tyr ochre suppressors (SUP-o) arise at a very high <span class="hlt">frequency</span> to produce this phenotypic <span class="hlt">variation</span>. The SUP-o mutations are highly pleiotropic. In addition, although all SUP-o mutations within the eight-member tRNA-Tyr gene family suppress the ochre mutation reporter, there are considerable phenotypic differences among the different SUP-o mutants. Finally, and of particular interest, there is a strong position effect on mutation <span class="hlt">frequency</span> within the eight-member tRNA-Tyr gene family, with one locus, SUP6, mutating at a much higher than average <span class="hlt">frequency</span> and two other loci, SUP2 and SUP8, mutating at much lower than average <span class="hlt">frequencies</span>. Mechanisms for the position effect on mutation <span class="hlt">frequency</span> are evaluated. PMID:12196388</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JIMTW..37..944P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JIMTW..37..944P"><span>A Tri-Band <span class="hlt">Frequency</span> Selective Surface (FSS) to Diplex Widely <span class="hlt">Separated</span> Bands for Millimeter Wave Remote Sensing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poojali, Jayaprakash; Ray, Shaumik; Pesala, Bala; Chitti, Krishnamurthy V.; Arunachalam, Kavitha</p> <p>2016-10-01</p> <p>A substrate-backed <span class="hlt">frequency</span> selective surface (FSS) is presented for diplexing the widely <span class="hlt">separated</span> <span class="hlt">frequency</span> spectrum centered at 55, 89, and 183 GHz with varying bandwidth for spatial <span class="hlt">separation</span> in the quasi-optical feed network of the millimeter wave sounder. A unit cell composed of a crossed dipole integrated with a circular ring and loaded inside a square ring is optimized for tri-band <span class="hlt">frequency</span> response with transmission window at 89 GHz and rejection windows at 55 and 183 GHz. The reflection and transmission losses predicted for the optimized unit cell (728 μm × 728 μm) composed of dissimilar resonant shapes is less than 0.5 dB for transverse electric (TE) and transverse magnetic (TM) polarizations and wide angle of incidence (0°-45°). The FSS is fabricated on a 175-μm-thick quartz substrate using microfabrication techniques. The transmission characteristics measured with continuous wave (CW) terahertz transmit receive system are in good agreement with the numerical simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1077846','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1077846"><span>Methylene singlet-triplet <span class="hlt">separation</span>. An explicit <span class="hlt">variational</span> treatment of many-body correlation effects</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Saxe, Paul; Schaefer, III, Henry F.; Handy, Nicholas C.</p> <p>1981-04-01</p> <p>The electronic structure of CH<sub>2</sub> has been addressed in this study using theoretical techniques which allow for the <span class="hlt">variational</span> inclusion of large classes of excitions differing by more than two electrons from the Hartree-Fock description. Specifically, a natural orbital transformation has been used to define orbitals for a full configuration interaction (CI) within the valence electron space. In addition, these full valence CI's include 56 configurations for <sup>1</sup>A<sub>1</sub> methylene and 51 configurations for <sup>3</sup>B<sub>1</sub> CH<sub>2</sub>. Subsequently all single and double excitations with respect to all configurations in the full valence are included in the final <span class="hlt">variation</span> treatments, which involved 57,684 configurations (<sup>1</sup>A<sub>1</sub>) and 84,536 configurations (<sup>3</sup>B<sub>1</sub>).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA610255','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA610255"><span>Approximate <span class="hlt">Separability</span> of Green’s Function for High <span class="hlt">Frequency</span> Helmholtz Equations</span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>2014-09-01</p> <p>developing fast algorithms. (a) In [24, 6, 18] fast butterfly algorithms for computing highly oscillatory Fourier integral APPROXIMATE <span class="hlt">SEPARABILITY</span> OF... butterfly algorithm is tight. Let r(X), r(Y ) denote the diameters of X,Y respectively. Denote the distance between X and Y to be dist(X,Y ). Without loss...HONGKAI ZHAO In a typical setup for butterfly algorithm [24, 6, 18], there are two domains A,B whose sizes are of O(1) and dist(A,B) = O(1). For</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhRvB..82w5431D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhRvB..82w5431D"><span><span class="hlt">Separating</span> surface structure and surface charge with second-harmonic and sum-<span class="hlt">frequency</span> scattering</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Beer, Alex G. F.; Campen, R. Kramer; Roke, Sylvie</p> <p>2010-12-01</p> <p>We analyze the effect of an electrostatic surface charge on the angular nonlinear light scattering pattern from spherical particles in solution. An electrostatic field near a charged interface leads to a bulk-allowed third-order process, the strength of which is proportional to the electrostatic surface potential. The commonly isotropic nature of the bulk leads to a fixed angular scattering pattern with fixed intensity ratios between polarizations. We show that second- and third-order scattering effects are <span class="hlt">separable</span> due to their different angular radiation patterns. Furthermore, nonlinear light scattering from a third-order contribution is strongest in the ppp polarization combination.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23058229','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23058229"><span>Multiphysics modelling of the <span class="hlt">separation</span> of suspended particles via <span class="hlt">frequency</span> ramping of ultrasonic standing waves.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Trujillo, Francisco J; Eberhardt, Sebastian; Möller, Dirk; Dual, Jurg; Knoerzer, Kai</p> <p>2013-03-01</p> <p>A model was developed to determine the local changes of concentration of particles and the formations of bands induced by a standing acoustic wave field subjected to a sawtooth <span class="hlt">frequency</span> ramping pattern. The mass transport equation was modified to incorporate the effect of acoustic forces on the concentration of particles. This was achieved by balancing the forces acting on particles. The <span class="hlt">frequency</span> ramping was implemented as a parametric sweep for the time harmonic <span class="hlt">frequency</span> response in time steps of 0.1s. The physics phenomena of piezoelectricity, acoustic fields and diffusion of particles were coupled and solved in COMSOL Multiphysics™ (COMSOL AB, Stockholm, Sweden) following a three step approach. The first step solves the governing partial differential equations describing the acoustic field by assuming that the pressure field achieves a pseudo steady state. In the second step, the acoustic radiation force is calculated from the pressure field. The final step allows calculating the locally changing concentration of particles as a function of time by solving the modified equation of particle transport. The diffusivity was calculated as function of concentration following the Garg and Ruthven equation which describes the steep increase of diffusivity when the concentration approaches saturation. However, it was found that this steep increase creates numerical instabilities at high voltages (in the piezoelectricity equations) and high initial particle concentration. The model was simplified to a pseudo one-dimensional case due to computation power limitations. The predicted particle distribution calculated with the model is in good agreement with the experimental data as it follows accurately the movement of the bands in the centre of the chamber.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhyA..392.4279S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhyA..392.4279S"><span>Irreversibility and entropy production in transport phenomena, IV: Symmetry, integrated intermediate processes and <span class="hlt">separated</span> <span class="hlt">variational</span> principles for multi-currents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suzuki, Masuo</p> <p>2013-10-01</p> <p>The mechanism of entropy production in transport phenomena is discussed again by emphasizing the role of symmetry of non-equilibrium states and also by reformulating Einstein’s theory of Brownian motion to derive entropy production from it. This yields conceptual reviews of the previous papers [M. Suzuki, Physica A 390 (2011) 1904; 391 (2012) 1074; 392 (2013) 314]. <span class="hlt">Separated</span> <span class="hlt">variational</span> principles of steady states for multi external fields {Xi} and induced currents {Ji} are proposed by extending the principle of minimum integrated entropy production found by the present author for a single external field. The basic strategy of our theory on steady states is to take in all the intermediate processes from the equilibrium state to the final possible steady states in order to study the irreversible physics even in the steady states. As an application of this principle, Gransdorff-Prigogine’s evolution criterion inequality (or stability condition) dXP≡∫dr∑iJidXi≤0 is derived in the stronger form dQi≡∫drJidXi≤0 for individual force Xi and current Ji even in nonlinear responses which depend on all the external forces {Xk} nonlinearly. This is called “<span class="hlt">separated</span> evolution criterion”. Some explicit demonstrations of the present general theory to simple electric circuits with multi external fields are given in order to clarify the physical essence of our new theory and to realize the condition of its validity concerning the existence of the solutions of the simultaneous equations obtained by the <span class="hlt">separated</span> <span class="hlt">variational</span> principles. It is also instructive to compare the two results obtained by the new <span class="hlt">variational</span> theory and by the old scheme based on the instantaneous entropy production. This seems to be suggestive even to the energy problem in the world.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5006941','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5006941"><span>Perceptual Qualities of Ethanol Depend on Concentration, and <span class="hlt">Variation</span> in These Percepts Associates with Drinking <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>Nolden, Alissa A.</p> <p>2016-01-01</p> <p>Introduction Ethanol, the pharmaceutically active ingredient in all alcoholic beverages, elicits multiple percepts including sweet, bitter, drying, and burning. However, quality-specific perceptual dose-response functions have not been previously reported. Also, individual differences in ethanol perception may associate with differences in alcoholic beverage use. Here, we describe the chemosensory profile of ethanol across concentrations in a convenience sample of mixed-age adults; secondarily, we explore whether individual differences in various qualities from ethanol associate with alcohol use behaviors. Methods Participants (n=100, 33 men) aged 21 to 55 (mean 33 years) tasted ethanol in water (4, 8, 16, 32, and 48 % v/v) and rated sweetness, bitterness, drying, and burning/tingling on four general Labeled Magnitude Scales. Demographic question and alcohol use measures (years drinking and reported <span class="hlt">frequency</span> of drinking occasions) were also collected. Results Intensity of most qualities increased as a function of ethanol concentration, although the dominant sensation differed with concentration. The dominant sensation for 8 and 16 % ethanol was bitterness (7.4±1.0; 13.5±1.4), whereas for 32 and 48 % ethanol, burning/tingling was the dominant sensation (29.7±2.1; 44.7±2.4). <span class="hlt">Variation</span> in quality-specific intensities of sampled ethanol explained variability in the reported intake <span class="hlt">frequency</span> for beer, wine, straight spirits, and number of drinking occasions. The number of years reported drinking (grand mean 10.5±0.8) was not significantly associated with perceptual ratings for sampled ethanol. Conclusions In a convenience sample of mixed-aged adults, the sensations from suprathreshold ethanol varied by concentration: bitterness dominated at lower concentrations, while burn dominated at higher concentrations. Exploratory analyses also suggest that differences in chemosensory responses across participants may associate with measures of alcohol use. PMID:27594968</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27723609','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27723609"><span>Illumination <span class="hlt">Variation</span>-Resistant Video-Based Heart Rate Measurement Using Joint Blind Source <span class="hlt">Separation</span> and Ensemble Empirical Mode Decomposition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cheng, Juan; Chen, Xun; Xu, Lingxi; Wang, Z Jane</p> <p>2016-10-06</p> <p>Recent studies have demonstrated that heart rate (HR) could be estimated using video data (e.g., exploring human facial regions of interest (ROIs)) under well controlled conditions. However, in practice, the pulse signals may be contaminated by motions and illumination <span class="hlt">variations</span>. In this paper, tackling the illumination <span class="hlt">variation</span> challenge, we propose an illuminationrobust framework using joint blind source <span class="hlt">separation</span> (JBSS) and ensemble empirical mode decomposition (EEMD) to effectively evaluate HR from webcam videos. The framework takes the hypotheses that both facial ROI and background ROI have similar illumination <span class="hlt">variations</span>. The background ROI is then considered as a noise reference sensor to denoise the facial signals by using the JBSS technique to extract the underlying illumination <span class="hlt">variation</span> sources. Further, the reconstructed illumination-resisted green channel of the facial ROI is detrended and decomposed into a number of intrinsic mode functions (IMFs) using EEMD to estimate the HR. Experimental results demonstrated that the proposed framework could estimate HR more accurately than the state-of-the-art methods. The Bland-Altman plots showed that it led to better agreement with HR ground truth with the mean bias 1.15 beat per minute (bpm), with 95 % limits from -15.43 bpm to 17.73 bpm, and the correlation coefficient 0.53. This study provides a promising solution for realistic non-contact and robust HR measurement applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5378544','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5378544"><span><span class="hlt">Frequency</span> of and <span class="hlt">variation</span> in low-value care in primary care: a retrospective cohort study</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Pendrith, Ciara; Bhatia, Meghan; Ivers, Noah M.; Mecredy, Graham; Tu, Karen; Hawker, Gillian A.; Jaglal, Susan B.; Wilson, Lynn; Wintemute, Kimberly; Glazier, Richard H.; Levinson, Wendy; Bhatia, R. Sacha</p> <p>2017-01-01</p> <p>Background: Low-value care, defined as care with a lack of benefit, can lead to higher health care costs, inconvenience to patients and, in some cases, harm to patients. The objectives of this study are to conduct exploratory analyses to understand how frequently selected low-value tests are ordered, to assess the degree of <span class="hlt">variation</span> in ordering that exists across regions and practices, and to identify services that may warrant further investigation and targeted interventions. Methods: We conducted a population-based retrospective cohort study using administrative health care databases from Ontario to identify rates of use of the following low-value services between fiscal years 2008/09 and 2012/13: computed tomography (CT) or magnetic resonance imaging (MRI) after a diagnosis of low back pain, Papanicolaou testing in women less than 21 years of age or older than 69 years of age and repeated dual-energy X-ray absorptiometry (DEXA) scanning within 2 years of an index scan. Regional and practice-level rates were calculated. Bivariate analyses were conducted to explore associations between patient factors and repeat DEXA scans. Results: Repeated DEXA scans were the most common service (21.0%), whereas cervical cancer screening among women less than 21 years of age or older than 69 years of age (8.0%) and CT or MRI imaging for low back pain (4.5%) were less common. There was substantial <span class="hlt">variation</span> across practices with rates of repeated DEXA scans, ranging from 4.0% to 54.9%, and cervical cancer screening, ranging from 0.9% to 35.2%. Patients with a high-risk index DEXA were more likely to receive a repeat scan (28.1%) than those with a baseline (8.9%) or low-risk (8.1%) scan. Interpretation: There is significant, practice-level <span class="hlt">variation</span> in the <span class="hlt">frequency</span> of low-value testing for DEXA scans, back imaging and cervical cancer screening. There is a particular need for interventions that aim to reduce unnecessary DEXA scans.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/14581','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/14581"><span>Development of Equipment to <span class="hlt">Separate</span> Nonthermal and Thermal Effects of Radio <span class="hlt">Frequency</span> Energy on Microorganisms</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>D.J. Geveke; M. Kozempel; C. Brunkhorst</p> <p>1999-11-01</p> <p>A radio <span class="hlt">frequency</span> (RF) dielectric heater has been developed for isolating thermal and nonthermal effects of RF energy on microorganisms in liquid foods. The modified heater enables the simultaneous application of RF energy and removal of thermal energy from the liquids. A double-pipe heat exchanger is an integral part of the heater. The outer pipe is made of Teflon. The inner pipe is made of stainless steel that is grounded in the RF circuit. Liquid food flows through the annular region between the two concentric pipes. Cooling water flows through the stainless steel pipe. The food in the annular region absorbs the RF energy. Concurrently, the cooling water flowing in the inner pipe removes the thermal energy from the food, thus controlling the temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940011845','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940011845"><span><span class="hlt">Separation</span> of topographic and intrinsic backscatter <span class="hlt">variations</span> in biscopic radar images: A magic airbrush</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kirk, R. L.</p> <p>1993-01-01</p> <p>Shaded-relief maps portraying landforms as they would appear in the absence of <span class="hlt">variations</span> in the intrinsic brightness of the surface are a venerable and extremely useful tool in planetary geology. Such maps have traditionally been produced by a highly labor intensive manual process. Skilled cartographer-artists develop detailed mental images of landforms by meticulous scrutiny of all available data, and are able to use an airbrush and electric eraser to draw these images on a map. This process becomes increasingly time-consuming or even impossible if - as is true for radar data in general and Magellan data in particular - the effects on image brightness of varying scattering properties greatly outweigh those of slope <span class="hlt">variations</span>. Because of the difficulty of interpreting relief in the Magellan images, the airbrush technique is being used only to remove obvious artifacts from low-resolution, shaded-relief images computed digitally from altimetric data. A surprisingly simple digital-processing technique that can be applied to pairs of radar images to produce shaded-relief-like results at the full image resolution is described. These shaded-relief images can be used not only as base maps, but to improve the accuracy of quantitative topographic mapping by radarclinometry and stereoanalysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4590873','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4590873"><span>Seasonal <span class="hlt">Variation</span> and <span class="hlt">Frequency</span> Distribution of Ectoparasites in Crossbreed Cattle in Southeastern Brazil</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ferraz da Costa, Maria do Socorro; Guimarães, Marcos Pezzi; Lima, Walter dos Santos; Ferraz da Costa, Ana Julia; Facury Filho, Elias Jorge; Araujo, Ricardo Nascimento</p> <p>2014-01-01</p> <p>The aims of this study were to evaluate the seasonal <span class="hlt">variation</span> and <span class="hlt">frequency</span> distribution of Rhipicephalus (Boophilus) microplus, Haematobia irritans, and Dermatobia hominis on crossbred heifers under field conditions in the northeast of Minas Gerais state, southeastern Brazil. From November 2007 to September 2009 (23 months), 40 heifers aged 16.6 ± 2.4 months were divided into groups A (1/4 Holstein × 3/4 Gir) and B (1/2 Holstein × 1/2 Gir) and had the monthly infestation estimated along with the climatic conditions. The mean maximum and minimum temperatures were 28.5 and 19°C, respectively. The ectoparasites were present on animals in all months of the year. The levels of ticks on the animals were low (3.0 ± 0.2 ticks/animal), with the highest density in midwinter. The temperature was the climatic factor that most influenced the tick levels. The population of H. irritans (13.9 ± 0.3 flies/animal) and D. hominis (1.5 ± 0.2 larvae/animal) on heifers was more influenced by rainfall and exhibited two population peaks during the year. 1/2 Holstein heifers harbored significantly more H. irritans and D. hominis than 1/4 Holstein heifers. The results are discussed considering the most appropriate periods to apply ectoparasiticides and the genetic make-up of the animals. PMID:26464941</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JBO....21k4001V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JBO....21k4001V"><span><span class="hlt">Separating</span> melanin from hemodynamics in nevi using multimode hyperspectral dermoscopy and spatial <span class="hlt">frequency</span> domain spectroscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vasefi, Fartash; MacKinnon, Nicholas; Saager, Rolf; Kelly, Kristen M.; Maly, Tyler; Booth, Nicholas; Durkin, Anthony J.; Farkas, Daniel L.</p> <p>2016-11-01</p> <p>Changes in the pattern and distribution of both melanocytes (pigment producing) and vasculature (hemoglobin containing) are important in distinguishing melanocytic proliferations. The ability to accurately measure melanin distribution at different depths and to distinguish it from hemoglobin is clearly important when assessing pigmented lesions (benign versus malignant). We have developed a multimode hyperspectral dermoscope (SkinSpect™) able to more accurately image both melanin and hemoglobin distribution in skin. SkinSpect uses both hyperspectral and polarization-sensitive measurements. SkinSpect's higher accuracy has been obtained by correcting for the effect of melanin absorption on hemoglobin absorption in measurements of melanocytic nevi. In vivo human skin pigmented nevi (N=20) were evaluated with the SkinSpect, and measured melanin and hemoglobin concentrations were compared with spatial <span class="hlt">frequency</span> domain spectroscopy (SFDS) measurements. We confirm that both systems show low correlation of hemoglobin concentrations with regions containing different melanin concentrations (R=0.13 for SFDS, R=0.07 for SkinSpect).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPS...272...24M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPS...272...24M"><span>Temporal <span class="hlt">variations</span> of cathode performance in air-cathode single-chamber microbial fuel cells with different <span class="hlt">separators</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, Jinxing; Wang, Zhiwei; Suor, Denis; Liu, Shumeng; Li, Jiaqi; Wu, Zhichao</p> <p>2014-12-01</p> <p>An ideal <span class="hlt">separator</span> is essential for efficient power production from air-cathode single-chamber microbial fuel cells (MFCs). In this study, we use different kinds of membranes as <span class="hlt">separators</span>, including Nafion 117 proton exchange membrane, polyethersulfone and poly(vinylidene fluoride) microfiltration membranes. Temporal <span class="hlt">variations</span> of cathode performance are monitored during the experiment. Results show that MFCs with microfiltration membranes present higher power output but deterioration is still observed after about 600-h operation. With the utilization of appropriate <span class="hlt">separators</span> (e.g., polyethersulfone membrane), biofouling, cation fouling and chemical scale fouling of the cathodes are alleviated while reaction fouling seems inevitable. Moreover, it is found that Coulombic efficiency (CE) and energy efficiency (EE) are also related to the cathode performance. Despite relatively high oxygen diffusivity (1.49 × 10-5 cm2 s-1), CE and EE of the MFC with 0.1 μm pore-size polyethersulfone membrane can reach 92.8% and 13.7%, respectively, when its average power density registers 403.5 mW m-2. This phenomenon might be attributed to the finding that the overall substrate consumption rate due to oxygen reduction and respiration is almost constant in the air-cathode MFCs. Oxygen leakage into the electrolyte can be inhibited due to the efficient oxygen reduction reaction on the surface of the cathode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JGR...10613711R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JGR...10613711R"><span>High-<span class="hlt">frequency</span> <span class="hlt">variations</span> in Earth rotation from Global Positioning System data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rothacher, M.; Beutler, G.; Weber, R.; Hefty, J.</p> <p>2001-01-01</p> <p>Using the data of the global, dense Global Positioning System (GPS) network established by the International GPS Service a continuous, uninterrupted series of subdaily Earth rotation parameters (ERPs) with a time resolution of 2 hours has been generated at the Center for Orbit Determination in Europe. The series starts in January 1995 and has a length of more than 3 years. Starting from the 2-hour ERP values of this, to our knowledge, unique time series, the high-<span class="hlt">frequency</span> <span class="hlt">variations</span> in Universal Time (UT1) and polar motion (PM) due to ocean tides are studied and a set of sine and cosine coefficients is estimated for all the major tidal terms at nearly diurnal and semidiurnal <span class="hlt">frequencies</span>. The GPS series is not very homogeneous (various processing changes during the 3 years) and still short compared to the length of very long baseline interferometry (VLBI) and satellite laser ranging (SLR) data sets. However, the results derived from this series are already of the same quality as the results from VLBI and SLR. A comparison of the tidal coefficients stemming from all three space-geodetic techniques shows an agreement on the 1 μs level for UT1 and 10 microarc seconds (μas) for PM, respectively. The RMS difference between the ocean tide amplitudes estimated from GPS data and from TOPEX/Poseidon altimeter data amounts to 0.7-0.9 μs in UT1 and 9-13 μas in PM. The residual spectrum that remains after the removal of all tidal terms has a noise level of ˜5-10 μas in PM and 0.5-1 μs in UT1 and contains nontidal signals (up to 55 μas in PM and 3 μs in UT1) that might be due to the impact of the satellite orbit modeling (12-hour revolution period of the satellites) or, alternatively, due to atmospheric or oceanic normal modes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRD..120.8743H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRD..120.8743H"><span>Impact of atmospheric changes on the low-<span class="hlt">frequency</span> <span class="hlt">variations</span> of convective afternoon rainfall activity over Taiwan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, Wan-Ru; Hsu, Huang-Hsiung; Wang, Shih-Yu; Chen, Jian-Pu</p> <p>2015-09-01</p> <p>This study examines the characteristics of low-<span class="hlt">frequency</span> <span class="hlt">variations</span> (defined as decadal-scale changes) in summer (June-August) convective afternoon rainfall (CAR) activity over Taiwan during 1961-2012. Using 3-hourly rain gauge data, it was found that (1) the CAR <span class="hlt">frequency</span> exhibits a secular trend and the 10-20 decadal oscillation, (2) the trend in CAR <span class="hlt">frequency</span> is positive in northern Taiwan but negative in central and southern Taiwan, and (3) the CAR rate increased over most of the lower plains but decreased over the mountain range of Taiwan. Diagnoses using the Japanese ReAnalysis (JRA-55) data and surface observations indicate that the low-<span class="hlt">frequency</span> <span class="hlt">variations</span> in CAR <span class="hlt">frequency</span> are closely associated with the <span class="hlt">variations</span> in monsoon southwesterly winds over the South China Sea and island-wide sea breeze convergence. The regional low-level circulation changes are linked to sea surface temperature anomalies over the Niño-4 region and its 10-20 year (quasi-decadal) oscillation. Regarding the processes that change the CAR rate in the trending patterns, it was found that increases in the moisture flux convergence and the moist (conditional) instability over the lower plains together explain the stronger CAR events in the long run.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A31E0113W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A31E0113W"><span>A mechanism for decadal <span class="hlt">variations</span> in the <span class="hlt">frequency</span> of extreme El Niño events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, G.; Cai, W.</p> <p>2015-12-01</p> <p>The El Niño Southern Oscillation (ENSO), the largest source of Earth's climate variability on interannual time scales, has massive impacts on extreme weathers, agriculture and ecosystems, particularly during extreme El Niño events, such as the 1982/83 and 1997/98 episodes. However, the associated mechanism is not fully understood, hindering their forecasts, as attested by the false alarm of an extreme El Niño in 2014 predicted by many models. Recent studies have identified additional precursors beyond westerly wind anomalies and oceanic heat content along the equatorial Pacific, including the southwest Pacific southerly jets, which tend to occur strongly and concurrently with equatorial westerly anomalies during extreme El Niño, but NOT during weak El Niño events. Here we show that the concurrences of southwest Pacific southerlies, anomalous equatorial westerlies, and their relationship, are modulated by the Pacific Decadal Oscillation (PDO)/Interdecadal Pacific Oscillation (IPO), even on daily timescales. During a positive phase of the PDO/IPO, occurrences of westerly wind events (WWEs), in the region between the Maritime continent and the eastern Pacific Ocean, are reinforced by the southwest Pacific southerly surges (SPSSs) in austral winter. By contrast, during a negative phase of the PDO/IPO, such SPSSs are not reinforcing WWEs; instead stronger SPSSs are associated with weaker WWEs. This interdecadal contrast in the relationship between SPSSs and WWEs contributes to the decadal <span class="hlt">variations</span> in the <span class="hlt">frequency</span> of extreme El Niño events. The associated mechanism will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22548454','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22548454"><span>SU-E-T-408: Evaluation of the Type and <span class="hlt">Frequency</span> of <span class="hlt">Variations</span> Discovered During Routine Secondary Patient Chart Review</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hardin, M; Harrison, A; Lockamy, V; Li, J; Peng, C; Potrebko, P; Yu, Y; Doyle, L; Cao, J</p> <p>2015-06-15</p> <p>Purpose: Desire to improve efficiency and throughput inspired a review of our physics chart check procedures. Departmental policy mandates plan checks pre-treatment, after first treatment and weekly every 3–5 days. This study examined the effectiveness of the “after first” check with respect to improving patient safety and clinical efficiency. Type and <span class="hlt">frequency</span> of <span class="hlt">variations</span> discovered during this redundant secondary review was examined over seven months. Methods: A community spreadsheet was created to record <span class="hlt">variations</span> in care discovered during chart review following the first fraction of treatment and before the second fraction (each plan reviewed prior to treatment). Entries were recorded from August 2014 through February 2015, amounting to 43 recorded <span class="hlt">variations</span> out of 906 reviewed charts. The <span class="hlt">variations</span> were divided into categories and <span class="hlt">frequencies</span> were assessed month-to-month. Results: Analysis of recorded <span class="hlt">variations</span> indicates an overall <span class="hlt">variation</span> rate of 4.7%. The initial rate was 13.5%; months 2–7 average 3.7%. The majority of <span class="hlt">variations</span> related to discrepancies in documentation at 46.5%, followed by prescription, plan deficiency, and dose tracking related <span class="hlt">variations</span> at 25.5%, 12.8%, and 12.8%, respectively. Minor <span class="hlt">variations</span> (negligible consequence on patient treatment) outweighed major <span class="hlt">variations</span> 3 to 1. Conclusion: This work indicates that this redundant secondary check is effective. The first month spike in rates could be due to the Hawthorne/observer effect, but the consistent 4% <span class="hlt">variation</span> rate suggests the need for periodical re-training on <span class="hlt">variations</span> noted as frequent to improve awareness and quality of the initial chart review process, which may lead to improved treatment quality, patient safety and increased clinical efficiency. Utilizing these results, a continuous quality improvement process following Deming’s Plan-Do-Study-Act (PDSA) methodology was generated. The first iteration of this PDSA was adding a specific dose tracking</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_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" 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_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</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="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoJI.207.1030H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoJI.207.1030H"><span><span class="hlt">Variation</span> in high-<span class="hlt">frequency</span> wave radiation from small repeating earthquakes as revealed by cross-spectral analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hatakeyama, Norishige; Uchida, Naoki; Matsuzawa, Toru; Okada, Tomomi; Nakajima, Junichi; Matsushima, Takeshi; Kono, Toshio; Hirahara, Satoshi; Nakayama, Takashi</p> <p>2016-11-01</p> <p>We examined the <span class="hlt">variation</span> in the high-<span class="hlt">frequency</span> wave radiation for three repeating earthquake sequences (M = 3.1-4.1) in the northeastern Japan subduction zone by waveform analyses. Earthquakes in each repeating sequence are located at almost the same place and show low-angle thrust type focal mechanisms, indicating that they represent repeated ruptures of a seismic patch on the plate boundary. We calculated cross-spectra of the waveforms and obtained the phases and coherences for pairs of events in the respective repeating sequences in order to investigate the waveform differences. We used waveform data sampled at 1 kHz that were obtained from temporary seismic observations we conducted immediately after the 2011 Tohoku earthquake near the source area. For two repeating sequences, we found that the interevent delay times for the two waveforms in a <span class="hlt">frequency</span> band higher than the corner <span class="hlt">frequencies</span> are different from those in a lower <span class="hlt">frequency</span> band for particular event pairs. The phases and coherences show that there are coherent high-<span class="hlt">frequency</span> waves for almost all the repeaters regardless of the high-<span class="hlt">frequency</span> delays. These results indicate that high-<span class="hlt">frequency</span> waves are always radiated from the same vicinity (subpatch) for these events but the time intervals between the ruptures of the subpatch and the centroid times can vary. We classified events in the sequence into two subgroups according to the high-<span class="hlt">frequency</span> band interevent delays relative to the low-<span class="hlt">frequency</span> band. For one sequence, we found that all the events that occurred just after (within 11 days) larger nearby earthquakes belong to one subgroup while other events belong to the other subgroup. This suggests that the high-<span class="hlt">frequency</span> wave differences were caused by stress perturbations due to the nearby earthquakes. In summary, our observations suggest that high-<span class="hlt">frequency</span> waves from the repeating sequence are radiated not from everywhere but from a long-duration subpatch within the seismic slip area. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED052010.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED052010.pdf"><span><span class="hlt">Variation</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>Hamilton City Board of Education (Ontario).</p> <p></p> <p>Suggestions for studying the topic of <span class="hlt">variation</span> of individuals and objects (balls) to help develop elementary school students' measurement, comparison, classification, evaluation, and data collection and recording skills are made. General suggestions of variables that can be investigated are made for the study of human <span class="hlt">variation</span>. Twelve specific…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E.200B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.200B"><span>Annual ionospheric <span class="hlt">variations</span> of the critical <span class="hlt">frequency</span> foF2 at the equatorial stations during the solar minima</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Biktash, Lilia</p> <p>2016-07-01</p> <p>We have analyzed annual ionospheric <span class="hlt">variations</span> of the critical <span class="hlt">frequency</span> foF2 at the equatorial stations during the solar minima. There are essential distinctions between the global TEC (total electron content) and foF2 annual <span class="hlt">variations</span> during the last two solar minima. Many authors concluded that the annual means of foF2 and the global TEC were reduced, while others investigations no found essential <span class="hlt">variations</span> as compared with the previous solar minimum. Most if not all of authors suppose that the possible source of this phenomenon is the low level of the EUV (extreme ultraviolet) during the solar minima. The aim of our paper is to amplify these conclusions or to propose new factor which can change ionosphere parameters during the solar minima. We calculated annual <span class="hlt">variations</span> of foF2 at the equatorial stations and compared these data with Dst annual <span class="hlt">variations</span>. We found that in addition to low level of the EUV during the solar minima, geomagnetic storms effects have to be included as the influencing factor on annual ionospheric <span class="hlt">variations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=318412','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=318412"><span>High <span class="hlt">frequency</span> genetic <span class="hlt">variation</span> of purine biosynthesis genes is a mechanism of success in Campylobacter jejuni</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Phenotypic <span class="hlt">variation</span> is prevalent among progeny of the zoonotic pathogen Campylobacter jejuni, the leading agent of enterocolitis in the developed world. Heterogeneity bestows increased survival to bacterial populations because variable phenotypes ensure some cells will be protected against future s...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19770012598&hterms=mother&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmother','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19770012598&hterms=mother&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmother"><span>Low <span class="hlt">frequency</span> electric field <span class="hlt">variations</span> during HF transmissions on a mother-daughter rocket</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rosenberg, T. J.; Maynard, M. C.; Holtet, J. A.; Karlsen, N. O.; Egeland, A.; Moe, T. E.; Troim, J.</p> <p>1977-01-01</p> <p>HF wave propagation experiments were conducted on Mother-Daughter rockets in the polar ionosphere. Swept <span class="hlt">frequency</span> transmissions from the Mother, nominally covering the range from 0.5 to 5 MHz in both CW and pulse modes, are received by the Daughter. In the most recent rocket of the series, the Mother also contained an AC electric field spectrometer covering the <span class="hlt">frequency</span> range from 10 Hz to 100 kHz in four decade bands. The low <span class="hlt">frequency</span> response of the ionosphere with respect to waves emitted from the onboard HF transmitter is examined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005ASAJ..117.2390M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005ASAJ..117.2390M"><span>The impact of <span class="hlt">variation</span> in low-<span class="hlt">frequency</span> interaural cross correlation on auditory spatial imagery in stereophonic loudspeaker reproduction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martens, William</p> <p>2005-04-01</p> <p>Several attributes of auditory spatial imagery associated with stereophonic sound reproduction are strongly modulated by <span class="hlt">variation</span> in interaural cross correlation (IACC) within low <span class="hlt">frequency</span> bands. Nonetheless, a standard practice in bass management for two-channel and multichannel loudspeaker reproduction is to mix low-<span class="hlt">frequency</span> musical content to a single channel for reproduction via a single driver (e.g., a subwoofer). This paper reviews the results of psychoacoustic studies which support the conclusion that reproduction via multiple drivers of decorrelated low-<span class="hlt">frequency</span> signals significantly affects such important spatial attributes as auditory source width (ASW), auditory source distance (ASD), and listener envelopment (LEV). A variety of methods have been employed in these tests, including forced choice discrimination and identification, and direct ratings of both global dissimilarity and distinct attributes. Contrary to assumptions that underlie industrial standards established in 1994 by ITU-R. Recommendation BS.775-1, these findings imply that substantial stereophonic spatial information exists within audio signals at <span class="hlt">frequencies</span> below the 80 to 120 Hz range of prescribed subwoofer cutoff <span class="hlt">frequencies</span>, and that loudspeaker reproduction of decorrelated signals at <span class="hlt">frequencies</span> as low as 50 Hz can have an impact upon auditory spatial imagery. [Work supported by VRQ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4349587','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4349587"><span><span class="hlt">Variation</span> in the <span class="hlt">Frequency</span> and Extent of Hybridization between Leucosceptrum japonicum and L. stellipilum (Lamiaceae) in the Central Japanese Mainland</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Yue; Maki, Masayuki</p> <p>2015-01-01</p> <p><span class="hlt">Variations</span> in the <span class="hlt">frequency</span> and extent of hybridization among mixed populations located in the same contact zone provide natural laboratories for the study of extrinsic reproductive isolation maintaining species integrity. In this study, we examined the pattern of hybridization between L. japonicum and L. stellipilum among mixed populations in different localities of a contact zone. The genetic structures from three sympatric populations and six mixed populations in the hybrid zone, and five reference populations far from the contact zone, were characterized using 10 neutral nuclear microsatellite markers. Evidence from genetic distance-based clustering analysis, the <span class="hlt">frequency</span> distribution of admixture proportion values, and the hybrid category assignment approaches indicated that the <span class="hlt">frequency</span> and extent of hybridization varied considerably among populations in the contact zone between L. japonicum and L. stellipilum. One likely explanation is that <span class="hlt">variation</span> in exogenous (ecological) selection among populations might contribute to differences in <span class="hlt">frequency</span> and extent of hybridization. The present study will facilitate future research exploring the evolution of reproductive isolation between L. japonicum and L. stellipilum. PMID:25738505</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=189923&keyword=washington+AND+beach&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=88133284&CFTOKEN=47240358','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=189923&keyword=washington+AND+beach&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=88133284&CFTOKEN=47240358"><span>Time-<span class="hlt">Frequency</span> Analysis of Beach Bacteria <span class="hlt">Variations</span> and its Implication for Recreational Water Quality Modeling</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>This paper explores the potential of time-<span class="hlt">frequency</span> wavelet analysis in resolving beach bacteria concentration and possible explanatory variables across multiple time scales with temporal information still preserved. The wavelet scalograms of E. coli concentrations and the explan...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRD..120.4600Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRD..120.4600Z"><span>Studies of the <span class="hlt">variations</span> of the first Schumann resonance <span class="hlt">frequency</span> during the solar flare on 7 March 2012</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, Hongjuan; Qiao, Xiaolin</p> <p>2015-05-01</p> <p>The ELF measurements at the YS station in China during the X5.4 solar flare on 7 March 2012 are examined. The first modal Schumann resonance (SR) <span class="hlt">frequencies</span> of the horizontal magnetic field components were found to increase by 0.1-0.2 Hz during the X-ray burst. During the enhancement of the proton flux, the first modal <span class="hlt">frequency</span> of the east-west magnetic field component decreases by approximately 0.6 Hz at most, while the <span class="hlt">variation</span> in the north-south magnetic field component is less well defined. The mechanisms of the <span class="hlt">variations</span> are simulated with a finite difference time domain technique by modeling the perturbed conductivity profile in the day-night asymmetric Earth-ionosphere cavity and modeling the global lightning source with the raw flash data measured by satellites. The simulated varying trends of the SR <span class="hlt">frequencies</span> observed near the ground with the altitudes of the conductivity perturbations are nearly the same as those previously reported and are interpreted by the two characteristic height model first proposed by Greifinger and Greifinger. It is concluded that the SR <span class="hlt">frequencies</span> increase for enhanced conductivity above the altitude of 60-70 km because of the lowered magnetic height and decrease for enhanced conductivity below this altitude due to the lowered electric height. This finding can explain the opposite behaviors of the SR <span class="hlt">frequencies</span> during X-ray bursts and strong solar proton events (SPEs). The simulation model in this work proved to be effective, with the simulated shifts in the values of SR <span class="hlt">frequencies</span> during X-ray bursts and SPEs being close to the practical measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PApGe.174.1043Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PApGe.174.1043Y"><span><span class="hlt">Frequency</span>-Dependent Amplitude Versus Offset <span class="hlt">Variations</span> in Porous Rocks with Aligned Fractures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Xiaohui; Cao, Siyuan; Guo, Quanshi; Kang, Yonggan; Yu, Pengfei; Hu, Wei</p> <p>2017-03-01</p> <p>The theory of <span class="hlt">frequency</span>-dependent amplitude versus offset (AVO) was developed for patchy-saturated model. In this work, we consider this theory in the case of an anisotropic medium based on a fractured-sandstone model. Thus, building on viscoelastic theory, we introduce a method for the computation of <span class="hlt">frequency</span>-dependent AVO that is suitable for use in the case of an anisotropic medium. We use both analytical methods and numerical simulations to study P-P and P-S reflection coefficients, and results suggest that dispersion and anisotropy should not be neglected in AVO analysis. Indeed, for class I AVO reservoirs, the reflection magnitude of P-wave increases with <span class="hlt">frequency</span>, while the responses of class II AVO reservoirs suggest that phase reversal occurs as <span class="hlt">frequency</span> increases positively. In the case of class III AVO reservoirs, reflection magnitude decreases as <span class="hlt">frequency</span> increases positively, while in the offset domain, the presence of anisotropy can distort or even reverse AVO responses. Thus, when compared to reflection coefficients for P-wave, reflection magnitude features of S-wave are more complex. The <span class="hlt">frequency</span>-dependent AVO responses reported in this study provide insights for the interpretation of seismic anomalies in vertical transverse isotropy (VTI) dispersive reservoirs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PApGe.tmp..189Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PApGe.tmp..189Y"><span><span class="hlt">Frequency</span>-Dependent Amplitude Versus Offset <span class="hlt">Variations</span> in Porous Rocks with Aligned Fractures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Xiaohui; Cao, Siyuan; Guo, Quanshi; Kang, Yonggan; Yu, Pengfei; Hu, Wei</p> <p>2016-11-01</p> <p>The theory of <span class="hlt">frequency</span>-dependent amplitude versus offset (AVO) was developed for patchy-saturated model. In this work, we consider this theory in the case of an anisotropic medium based on a fractured-sandstone model. Thus, building on viscoelastic theory, we introduce a method for the computation of <span class="hlt">frequency</span>-dependent AVO that is suitable for use in the case of an anisotropic medium. We use both analytical methods and numerical simulations to study P-P and P-S reflection coefficients, and results suggest that dispersion and anisotropy should not be neglected in AVO analysis. Indeed, for class I AVO reservoirs, the reflection magnitude of P-wave increases with <span class="hlt">frequency</span>, while the responses of class II AVO reservoirs suggest that phase reversal occurs as <span class="hlt">frequency</span> increases positively. In the case of class III AVO reservoirs, reflection magnitude decreases as <span class="hlt">frequency</span> increases positively, while in the offset domain, the presence of anisotropy can distort or even reverse AVO responses. Thus, when compared to reflection coefficients for P-wave, reflection magnitude features of S-wave are more complex. The <span class="hlt">frequency</span>-dependent AVO responses reported in this study provide insights for the interpretation of seismic anomalies in vertical transverse isotropy (VTI) dispersive reservoirs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27846291','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27846291"><span>Geographic <span class="hlt">Variation</span> in Festuca rubra L. Ploidy Levels and Systemic Fungal Endophyte <span class="hlt">Frequencies</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dirihan, Serdar; Helander, Marjo; Väre, Henry; Gundel, Pedro E; Garibaldi, Lucas A; Irisarri, J Gonzalo N; Saloniemi, Irma; Saikkonen, Kari</p> <p>2016-01-01</p> <p>Polyploidy and symbiotic Epichloë fungal endophytes are common and heritable characteristics that can facilitate environmental range expansion in grasses. Here we examined geographic patterns of polyploidy and the <span class="hlt">frequency</span> of fungal endophyte colonized plants in 29 Festuca rubra L. populations from eight geographic sites across latitudes from Spain to northernmost Finland and Greenland. Ploidy seemed to be positively and negatively correlated with latitude and productivity, respectively. However, the correlations were nonlinear; 84% of the plants were hexaploids (2n = 6x = 42), and the positive correlation between ploidy level and latitude is the result of only four populations skewing the data. In the southernmost end of the gradient 86% of the plants were tetraploids (2n = 4x = 28), whereas in the northernmost end of the gradient one population had only octoploid plants (2n = 8x = 56). Endophytes were detected in 22 out of the 29 populations. Endophyte <span class="hlt">frequencies</span> varied among geographic sites, and populations and habitats within geographic sites irrespective of ploidy, latitude or productivity. The highest overall endophyte <span class="hlt">frequencies</span> were found in the southernmost end of the gradient, Spain, where 69% of plants harbored endophytes. In northern Finland, endophytes were detected in 30% of grasses but endophyte <span class="hlt">frequencies</span> varied among populations from 0% to 75%, being higher in meadows compared to riverbanks. The endophytes were detected in 36%, 30% and 27% of the plants in Faroe Islands, Iceland and Switzerland, respectively. Practically all examined plants collected from southern Finland and Greenland were endophyte-free, whereas in other geographic sites endophyte <span class="hlt">frequencies</span> were highly variable among populations. Common to all populations with high endophyte <span class="hlt">frequencies</span> is heavy vertebrate grazing. We propose that the detected endophyte <span class="hlt">frequencies</span> and ploidy levels mirror past distribution history of F. rubra after the last glaciation period, and local</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5112939','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5112939"><span>Geographic <span class="hlt">Variation</span> in Festuca rubra L. Ploidy Levels and Systemic Fungal Endophyte <span class="hlt">Frequencies</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>Dirihan, Serdar; Helander, Marjo; Väre, Henry; Gundel, Pedro E.; Garibaldi, Lucas A.; Irisarri, J. Gonzalo N.; Saloniemi, Irma; Saikkonen, Kari</p> <p>2016-01-01</p> <p>Polyploidy and symbiotic Epichloë fungal endophytes are common and heritable characteristics that can facilitate environmental range expansion in grasses. Here we examined geographic patterns of polyploidy and the <span class="hlt">frequency</span> of fungal endophyte colonized plants in 29 Festuca rubra L. populations from eight geographic sites across latitudes from Spain to northernmost Finland and Greenland. Ploidy seemed to be positively and negatively correlated with latitude and productivity, respectively. However, the correlations were nonlinear; 84% of the plants were hexaploids (2n = 6x = 42), and the positive correlation between ploidy level and latitude is the result of only four populations skewing the data. In the southernmost end of the gradient 86% of the plants were tetraploids (2n = 4x = 28), whereas in the northernmost end of the gradient one population had only octoploid plants (2n = 8x = 56). Endophytes were detected in 22 out of the 29 populations. Endophyte <span class="hlt">frequencies</span> varied among geographic sites, and populations and habitats within geographic sites irrespective of ploidy, latitude or productivity. The highest overall endophyte <span class="hlt">frequencies</span> were found in the southernmost end of the gradient, Spain, where 69% of plants harbored endophytes. In northern Finland, endophytes were detected in 30% of grasses but endophyte <span class="hlt">frequencies</span> varied among populations from 0% to 75%, being higher in meadows compared to riverbanks. The endophytes were detected in 36%, 30% and 27% of the plants in Faroe Islands, Iceland and Switzerland, respectively. Practically all examined plants collected from southern Finland and Greenland were endophyte-free, whereas in other geographic sites endophyte <span class="hlt">frequencies</span> were highly variable among populations. Common to all populations with high endophyte <span class="hlt">frequencies</span> is heavy vertebrate grazing. We propose that the detected endophyte <span class="hlt">frequencies</span> and ploidy levels mirror past distribution history of F. rubra after the last glaciation period, and local</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910057123&hterms=Waterfalls&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWaterfalls','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910057123&hterms=Waterfalls&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWaterfalls"><span>Space Shuttle Redesigned Solid Rocket Motor nozzle natural <span class="hlt">frequency</span> <span class="hlt">variations</span> with burn time</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lui, C. Y.; Mason, D. R.</p> <p>1991-01-01</p> <p>The effects of erosion and thermal degradation on the Space Shuttle Redesigned Solid Rocket Motor (RSRM) nozzle's structural dynamic characteristics were analytically evaluated. Also considered was stiffening of the structure due to internal pressurization. A detailed NASTRAN finite element model of the nozzle was developed and used to evaluate the influence of these effects at several discrete times during motor burn. Methods were developed for treating erosion and thermal degradation, and a procedure was developed to account for internal pressure stiffening using differential stiffness matrix techniques. Results were verified using static firing test accelerometer data. Fast Fourier Transform and Maximum Entropy Method techniques were applied to the data to generate waterfall plots which track modal <span class="hlt">frequencies</span> with burn time. Results indicate that the lower <span class="hlt">frequency</span> nozzle 'vectoring' modes are only slightly affected by erosion, thermal effects and internal pressurization. The higher <span class="hlt">frequency</span> shell modes of the nozzle are, however, significantly reduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/972061','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/972061"><span>Searches for high <span class="hlt">frequency</span> <span class="hlt">variations</span> in the 8-B neutrino flux at the Sudbury neutrino observatory</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rielage, Keith; Seibert, Stanley R; Hime, Andrew; Elliott, Steven R; Stonehill, L C; Wouters, J M; Aharmim, B; Ahmed, S N; Anthony, A E; Barros, N; Beier, E W; Bellerive, A; Belttran, B; Bergevin, M; Biller, S D; Boudjemline, K; Burritt, T H; Cai, B; Chan, Y D; Chauhan, D; Chen, M; Cleveland, B T; Cox - Mobrand, G A; Dai, X; Deng, H; Detwiler, J; Dimarco, M; Doe, P J; Drouin, P - L; Duba, C A; Duncan, F A; Dunford, M; Earle, E D; Evans, H C; Ewan, G T; Farine, J; Fergani, H; Fleurot, F; Ford, R J; Formaggilo, J A; Gagnon, N; Goon, J Tm; Guillian, E; Habib, S; Hahn, R L; Hallin, A L; Hallman, E D; Harvey, P J; Hazama, R; Heintzelman, W J; Heise, J; Helmer, R L; Howard, C; Howe, M A; Huang, M; Jamieson, B; Jelley, N A; Keeter, K J; Klein, J R; Kos, M; Kraus, C; Krauss, C B; Kutter, T; Kyba, C C M; Law, J; Lawson, I T; Lesko, K T; Leslie, J R; Loach, J C; Maclellan, R; Majerus, S; Mak, H B; Maneira, J; Martin, R; Mccauley, N; Mc Donald, A B; Mcgee, S; Miffin, C; Miller, M L; Monreal, B; Monroe, J; Morissette, B; Nickel, B G; Noble, A J; O' Keeffe, H M; Oblath, N S; Orebi Gann, G D; Oser, S M; Ott, R A; Peeters, S J M; Poon, A W P; Prior, G; Reitzner, S D; Robertson, B C; Robertson, R G H; Rollin, E; Schwendener, M H; Secrest, J A; Seibert, S R; Simard, O; Sinclair, D; Sinclair, L; Skensved, P; Sonley, T J; Tesic, G; Tolich, N; Tsui, T; Tunnell, C D; Van Berg, R; Van Devender, B A; Virtue, C J; Wall, B L; Waller, D; Wan Chan Tseung, H; West, N; Wilkerson, J F; Wilson, J R; Wright, A; Yeh, M; Zhang, F; Zuber, K</p> <p>2009-01-01</p> <p>We have peformed three searches for high-<span class="hlt">frequency</span> signals in the solar neutrino flux measured by the Sudbury Neutrino Observatory (SNO), motivated by the possibility that solar g-mode oscillations could affect the production or propagation of solar {sup 8}B neutrinos. The first search looked for any significant peak in the <span class="hlt">frequency</span> range l/day to 144/day, with a sensitivity to sinusoidal signals with amplitudes of 12% or greater. The second search focused on regions in which g-mode signals have been claimed by experiments aboard the SoHO satellite, and was sensitive to signals with amplitudes of 10% or greater. The third search looked for extra power across the entire <span class="hlt">frequency</span> band. No statistically significant signal was detected in any of the three searches.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27382482','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27382482"><span>Path loss <span class="hlt">variation</span> of on-body UWB channel in the <span class="hlt">frequency</span> bands of IEEE 802.15.6 standard.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Goswami, Dayananda; Sarma, Kanak C; Mahanta, Anil</p> <p>2016-06-01</p> <p>The wireless body area network (WBAN) has gaining tremendous attention among researchers and academicians for its envisioned applications in healthcare service. Ultra wideband (UWB) radio technology is considered as excellent air interface for communication among body area network devices. Characterisation and modelling of channel parameters are utmost prerequisite for the development of reliable communication system. The path loss of on-body UWB channel for each <span class="hlt">frequency</span> band defined in IEEE 802.15.6 standard is experimentally determined. The parameters of path loss model are statistically determined by analysing measurement data. Both the line-of-sight and non-line-of-sight channel conditions are considered in the measurement. <span class="hlt">Variations</span> of parameter values with the size of human body are analysed along with the <span class="hlt">variation</span> of parameter values with the surrounding environments. It is observed that the parameters of the path loss model vary with the <span class="hlt">frequency</span> band as well as with the body size and surrounding environment. The derived parameter values are specific to the particular <span class="hlt">frequency</span> bands of IEEE 802.15.6 standard, which will be useful for the development of efficient UWB WBAN system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080007426','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080007426"><span>Active noise control using noise source having adaptive resonant <span class="hlt">frequency</span> tuning through stress <span class="hlt">variation</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pla, Frederic G. (Inventor); Rajiyah, Harindra (Inventor); Renshaw, Anthony A. (Inventor); Hedeen, Robert A. (Inventor)</p> <p>1995-01-01</p> <p>A noise source for an aircraft engine active noise cancellation system in which the resonant <span class="hlt">frequency</span> of a noise radiating element is tuned to permit noise cancellation over a wide range of <span class="hlt">frequencies</span>. The resonant <span class="hlt">frequency</span> of the noise radiating element is tuned by an expandable ring embedded in the noise radiating element. Excitation of the ring causes expansion or contraction of the ring, thereby varying the stress in the noise radiating element. The ring is actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage <span class="hlt">frequency</span> of the engine's fan. In response, the controller determines a control signal which is sent to the ring, causing the ring to expand or contract. Instead of a single ring embedded in the noise radiating panel, a first expandable ring can be bonded to one side of the noise radiating element, and a second expandable ring can be bonded to the other side.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.S33B4517R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.S33B4517R"><span>Corner <span class="hlt">Frequency</span> <span class="hlt">Variation</span> in the Southeastern Region of the 1992 Nicaragua Tsunami Earthquake</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rotman, H. M. M.; Bilek, S. L.; Phillips, W. S.</p> <p>2014-12-01</p> <p>At the Nicaragua portion of the Middle America Trench, where the Cocos Plate is subducting at ~85 mm/yr, a tsunami earthquake (mb 5.3, Ms 7.2, Mw 7.6) occurred at 15 km depth on 2 September 1992, causing a tsunami up to 8 m high and >116 deaths. A tsunami earthquake is characterized by deficiency in high <span class="hlt">frequency</span> radiated energy and large tsunami for its Ms. Tsunami earthquakes are relatively rare, but their occurrence presents a significant hazard to coastal populations, so the potential to identify tsunami earthquake regions has wide-reaching hazard implications. Here we examine the notion that the cause of the dominantly low <span class="hlt">frequency</span> energy in the 1992 tsunami earthquake may also manifest in small earthquakes in the same area. We examine 241 events within and south of the 1992 rupture limits with hypocenters 8-30 km depth and 1.7 < Mw < 4.6, recorded by land station and ocean bottom seismometers in southern Nicaragua and northern Costa Rica from November 2005 to June 2006. Event source parameters moment, corner <span class="hlt">frequency</span>, and stress drop are determined using the spectral ratios of S-wave coda. Mean stress drop inside the 1992 rupture area is 3.2 MPa, and immediately south of the 1992 rupture zone mean stress drop is 10.4 MPa. Inside and outside the 1992 rupture zone at similar depths, the increase in stress drop is by a factor of five and occurs abruptly over <50 km. The mean corner <span class="hlt">frequency</span> of events in the 1992 rupture area is ~45% the mean corner <span class="hlt">frequency</span> value for events south of the 1992 rupture zone. Therefore, our results demonstrate different source parameter characteristics for microseismicity in the region of a past tsunami earthquake. If this finding can be reproduced at other subduction zones, it may significantly improve subduction zone coastal hazard assessment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.5385J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.5385J"><span>Seasonal and regional <span class="hlt">variations</span> in extreme precipitation event <span class="hlt">frequency</span> using CMIP5</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Janssen, E.; Sriver, R. L.; Wuebbles, D. J.; Kunkel, K. E.</p> <p>2016-05-01</p> <p>Understanding how the <span class="hlt">frequency</span> and intensity of extreme precipitation events are changing is important for regional risk assessments and adaptation planning. Here we use observational data and an ensemble of climate change model experiments (from the Coupled Model Intercomparison Project Phase 5 (CMIP5)) to examine past and potential future seasonal changes in extreme precipitation event <span class="hlt">frequency</span> over the United States. Using the extreme precipitation index as a metric for extreme precipitation change, we find key differences between models and observations. In particular, the CMIP5 models tend to overestimate the number of spring events and underestimate the number of summer events. This seasonal shift in the models is amplified in projections. These results provide a basis for evaluating climate model skill in simulating observed seasonality and changes in regional extreme precipitation. Additionally, we highlight key sources of variability and uncertainty that can potentially inform regional impact analyses and adaptation planning.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.3104B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.3104B"><span>Capturing temporal <span class="hlt">variation</span> in phosphorus dynamics in groundwater dominated rivers using automated high-<span class="hlt">frequency</span> sampling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bieroza, M. Z.; Heathwaite, A. L.; Mullinger, N. J.; Keenan, P. O.</p> <p>2012-04-01</p> <p>High-<span class="hlt">frequency</span> river water quality monitoring provides detailed hydrochemical information on the time scale of hydrologic response. Several studies (Kirchner et al., 2004; Johnes, 2007; Cassidy and Jordan, 2011) have shown previously that coarse sampling approaches fail to quantify nutrient and sediment loads and to capture the fine structure of water quality dynamics correctly. A robust analysis of high-<span class="hlt">frequency</span> nutrient and water quality time series can present a complex conceptual, analytical and computational problem. High-<span class="hlt">frequency</span> nutrient monitoring provides new evidence of processes and patterns that could not be observed previously using standard coarse resolution sampling schemes. However, to fully utilise the wealth of information contained in high-<span class="hlt">frequency</span> nutrient data, we need to address the following questions: how to detect complex coupling patterns and processes in high-resolution flow-nutrients data, how do these patterns and processes change throughout the period of observation, and how to distinguish noise signals from an evidence of real processes (Harris and Heathwaite, 2005). Here, hourly measurements of total phosphorus (TP), soluble reactive phosphorus (SRP) and turbidity were carried out using bank side analysers to study the biogeochemical response of a 54 km2 catchment of the River Leith, a tributary of the River Eden (Cumbria, UK). A remote automated mobile lab facilitates real-time high-<span class="hlt">frequency</span> nutrient and water quality monitoring, with no time delay between collection and analysis of the reactive elements. The objectives of this study were two-fold: first to investigate the intrinsic complexity of the temporal relationship between phosphorus fractions (SRP, TP), turbidity and continuous hydrometric time series and secondly to investigate the possibilities of missing high-<span class="hlt">frequency</span> phosphorus data infilling using continuous hydrometric time series. Complex non-linear relationships between flow, TP and SRP, turbidity were observed</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_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" 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_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</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="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE10010E..38D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE10010E..38D"><span>A synthesis approach for antennas with a quasi-linear gain <span class="hlt">variation</span> over a wide <span class="hlt">frequency</span> range</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deacu, Daniela; Tamas, Razvan; Petrescu, Teodor; Tasu, Sorin</p> <p>2016-12-01</p> <p>In this paper, we propose to extend the <span class="hlt">frequency</span>-domain synthesis approach based on a variable slope profile for antennas with a linear <span class="hlt">variation</span> over a fractional bandwidth in the order of 100%. In that case the inflection point on the resulting profile is no longer located at its half. Thus, the profile shape will no longer be folded at the half, but at a coordinate closer to the end, the resulting shape approaching to a bow-tie antenna than to a circular dipole antenna.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6934698','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6934698"><span>MUF (maximum usable <span class="hlt">frequency</span>) (3000) as an indicator for F-region <span class="hlt">variations</span>. Final report, February 1986-August 1987</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Paul, A.K.</p> <p>1988-01-01</p> <p>Ionograms recorded at Brighton, Colorado during the last sunspot maximum are still being studied. Samples show that the high quality and high temporal resolution of the data may yield new information about the dynamics of the ionosphere, especially in the F region. F-region parameters from these data show that this part of the ionosphere is highly variable, with short periods of the order of the order of fractions of an hour. This report explains why the maximum usable <span class="hlt">frequency</span> (MUF) (3000) appears to be the most-appropriate indicator for F-region <span class="hlt">variations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/88805','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/88805"><span>Greater <span class="hlt">variation</span> in BCL-2 mutation <span class="hlt">frequency</span> among lymphocytes of heavy smokers than among those of controls</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cortopassi, G.A.; Liu, Y.; Bell, D.A.</p> <p>1994-12-31</p> <p>It is possible that the risk for tumors in specific human individuals might be most usefully estimated by determining the <span class="hlt">frequency</span> of (rare) somatic mutations at oncogenic loci in their tissue. Using a sensitive nested PCR assay, we have investigated the <span class="hlt">frequency</span> of rare t(14;18) (q32;q21) translocations at the bcl-2 proto-oncogene locus in peripheral blood lymphocytes of 85 smokers and 36 control non-smokers. The <span class="hlt">variation</span> in translocation <span class="hlt">frequencies</span> (plus or minus the <span class="hlt">variation</span> at the 95% confidence interval) were 1.4 {+-} -0.37 per million lymphocytes among smokers, versus 0.53 {+-} -0.20 among non-smokers, a 2.6-fold excess of such oncogenic translocations among lymphocytes of smokers. Logistic regression analysis including age, race, sex, years of smoking and pack-years indicated that only current smoking was significantly associated with increased <span class="hlt">frequency</span> of the translocation of bcl-2 occur in 85% of follicular lymphoma tumors, and about 50% of all Non-Hodgkin`s Lymphoma, and are thought to be the result of errors of the V(D)J recombinase. Epidemiological studies by others have shown that there is about a two-fold higher relative risk of Non-Hodgkin`s Lymphoma for heavy smokers vs. non-smokers. We speculate that one reason for excess NHL tumors among heavy smokers may be their increased average burden of t(14;18) mutations, and that smoke-derived substances may induce errors of the V(D)J recombinase by mutagenic or antigenic mechanisms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E2033M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E2033M"><span>Seasonal <span class="hlt">Variation</span> of the Minimum Value of Critical <span class="hlt">Frequency</span> of the Equatorial Ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mathew, Tiju Joseph; Prabhakaran Nayar, S. R.</p> <p></p> <p>Ionosonde data recorded at Trivandrum (8.33°N, 77°E, dip 0.4°N) during a year of high solar activity (2001) is used in this work to study the <span class="hlt">variation</span> of foF2 and h’F2 during pre-sunrise hours. The minimum value of pre-sunrise foF2 shows daily and seasonal <span class="hlt">variations</span>. It is found that the minimum value of foF2 is greater in December solstice. The minimum value of foF2 for each day is found to be related to the h’F2 values during early morning hours. On some days, the value of h’F 2 is found to be enhanced (greater than 300 km) during early morning hours (02:00 - 04:00 LT). On such days, the rate of decrease of foF2 is low and hence the minimum vale of foF2 will be relatively high.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16338015','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16338015"><span>Genetic <span class="hlt">variation</span> of individual alpha <span class="hlt">frequency</span> (IAF) and alpha power in a large adolescent twin sample.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Smit, Christine M; Wright, Margaret J; Hansell, Narelle K; Geffen, Gina M; Martin, Nicholas G</p> <p>2006-08-01</p> <p>To further clarify the mode of genetic transmission on individual alpha <span class="hlt">frequency</span> (IAF) and alpha power, the extent to which individual differences in these alpha indices are influenced by genetic factors were examined in a large sample of adolescent twins (237 MZ, 282 DZ pairs; aged 16). EEG was measured at rest (eyes closed) from the right occipital site, and a second EEG recording for 50 twin pairs obtained approximately 3 months after the initial collection, enabled an estimation of measurement error. Analyses confirmed a strong genetic influence on both IAF (h(2)=0.81) and alpha power (h(2)=0.82), and there was little support for non-additive genetic (dominance) variance. A small but significant negative correlation (-0.18) was found between IAF and alpha power, but genetic influences on IAF and alpha power were largely independent. All non-genetic variance was due to unreliability, with no significant variance attributed to unique environmental factors. Relationships between the alpha and IQ indices were also explored but were generally either non-significant or very low. The findings confirm the high heritability for both IAF and alpha power, they further suggest that the mode of genetic transmission is due to additive genetic factors, that genetic influences on the underlying neural mechanisms of alpha <span class="hlt">frequency</span> and power are largely specific, and that individual differences in alpha activity are influenced little by developmental plasticity and individual experiences.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JHyd..524..333B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JHyd..524..333B"><span>Seasonal <span class="hlt">variation</span> in phosphorus concentration-discharge hysteresis inferred from high-<span class="hlt">frequency</span> in situ monitoring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bieroza, M. Z.; Heathwaite, A. L.</p> <p>2015-05-01</p> <p>High-resolution in situ total phosphorus (TP), total reactive phosphorus (TRP) and turbidity (TURB) time series are presented for a groundwater-dominated agricultural catchment. Meta-analysis of concentration-discharge (c-q) intra-storm signatures for 61 storm events revealed dominant hysteretic patterns with similar <span class="hlt">frequency</span> of anti-clockwise and clockwise responses; different determinands (TP, TRP, TURB) behaved similarly. We found that the c-q loop direction is controlled by seasonally variable flow discharge and temperature whereas the magnitude is controlled by antecedent rainfall. Anti-clockwise storm events showed lower flow discharge and higher temperature compared to clockwise events. Hydrological controls were more important for clockwise events and TP and TURB responses, whereas in-stream biogeochemical controls were important for anti-clockwise storm events and TRP responses. Based on the best predictors of the direction of the hysteresis loops, we calibrated and validated a simple fuzzy logic inference model (FIS) to determine likely direction of the c-q responses. We show that seasonal and inter-storm succession in clockwise and anti-clockwise responses corroborates the transition in P transport from a chemostatic to an episodic regime. Our work delivers new insights for the evidence base on the complexity of phosphorus dynamics. We show the critical value of high-<span class="hlt">frequency</span> in situ observations in advancing understanding of freshwater biogeochemical processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005EOSTr..86...26P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005EOSTr..86...26P"><span>Forcing of polar motion in the Chandler <span class="hlt">frequency</span> band: An opportunity to evaluate interannual climate <span class="hlt">variations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Plag, H.-P.; Chao, B. F.; Gross, R. S.; Van Dam, T.</p> <p></p> <p>The Earth rotates about its axis once per day but does not do so uniformly. The length of the day changes by as much as a millisecond from day to day and the Earth wobbles as it rotates. That the Earth should wobble was predicted by the Swiss mathematician Leonhard Euler in 1765, but it was not until 1891 that the wobbling motion of the Earth was detected by the American astronomer Seth Carlo Chandler, Jr. In fact, Chandler observed that the Earth has two distinct wobbles, one with an annual period and the other with a 14-month period. The annual wobble is a forced motion of the Earth caused by seasonal <span class="hlt">variations</span> in the atmosphere, oceans, and hydrosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22365654','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22365654"><span><span class="hlt">Frequency</span> of close companions among Kepler planets—a transit time <span class="hlt">variation</span> study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Xie, Ji-Wei; Wu, Yanqin; Lithwick, Yoram E-mail: wu@astro.utoronto.ca</p> <p>2014-07-10</p> <p>A transiting planet exhibits sinusoidal transit time <span class="hlt">variations</span> (TTVs) if perturbed by a companion near a mean-motion resonance. We search for sinusoidal TTVs in more than 2600 Kepler candidates, using the publicly available Kepler light curves (Q0-Q12). We find that the TTV fractions rise strikingly with the transit multiplicity. Systems where four or more planets transit enjoy a TTV fraction that is roughly five times higher than those where a single planet transits, and about twice as high as those for doubles and triples. In contrast, models in which all transiting planets arise from similar dynamical configurations predict comparable TTV fractions among these different systems. One simple explanation for our results is that there are at least two different classes of Kepler systems, one closely packed and one more sparsely populated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ApJ...789..165X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ApJ...789..165X"><span><span class="hlt">Frequency</span> of Close Companions among Kepler Planets—a Transit Time <span class="hlt">Variation</span> Study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, Ji-Wei; Wu, Yanqin; Lithwick, Yoram</p> <p>2014-07-01</p> <p>A transiting planet exhibits sinusoidal transit time <span class="hlt">variations</span> (TTVs) if perturbed by a companion near a mean-motion resonance. We search for sinusoidal TTVs in more than 2600 Kepler candidates, using the publicly available Kepler light curves (Q0-Q12). We find that the TTV fractions rise strikingly with the transit multiplicity. Systems where four or more planets transit enjoy a TTV fraction that is roughly five times higher than those where a single planet transits, and about twice as high as those for doubles and triples. In contrast, models in which all transiting planets arise from similar dynamical configurations predict comparable TTV fractions among these different systems. One simple explanation for our results is that there are at least two different classes of Kepler systems, one closely packed and one more sparsely populated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ClDy...46.3405W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ClDy...46.3405W"><span>Can the Tibetan Plateau snow cover influence the interannual <span class="hlt">variations</span> of Eurasian heat wave <span class="hlt">frequency</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Zhiwei; Zhang, Peng; Chen, Hua; Li, Yun</p> <p>2016-06-01</p> <p>The Eurasian continent has experienced significant year-to-year <span class="hlt">variations</span> of summer heat waves during the past decades. Several possible factors, such as ocean temperature, soil moisture, and changes in land use and greenhouse gases, have been identified in previous studies, but the mechanisms are still unclear. In this study, it is found that the Tibetan Plateau snow cover (TPSC) is closely linked to the interannual <span class="hlt">variations</span> of summer heat waves over Eurasia. The TPSC variability explains more than 30 % of the total variances of heat wave variability in the southern Europe and northeastern Asia (SENA) region. A set of numerical experiments reveal that the reduced TPSC may induce a distinct teleconnection pattern across the Eurasian continent, with two anomalous high pressure centers in the upper troposphere over the SENA region, which may lead to a reduction of the cloud formation near the surface. The less cloud cover tends to increase the net shortwave radiation and favor a stronger surface sensible heat flux in the dry surface condition over the SENA region, resulting in a deeper, warmer and drier atmospheric boundary layer that would further inhibit the local cloud formation. Such a positive land-atmosphere feedback may dry the surface even further, heat the near-surface atmosphere and thereby intensify the local heat waves. The above dynamical processes also operate on interdecadal time scales. Given the reduction of the TPSC could become more pronounced with increasing levels of greenhouse gases in a warming climate, we infer that the TPSC may play an increasingly important role in shaping the summer heat waves over the SENA region in next decades.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMNS41B1685K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMNS41B1685K"><span>Development of a new medium <span class="hlt">frequency</span> EM device: Mapping soil water content <span class="hlt">variations</span> using electrical conductivity and dielectric permittivity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kessouri, P.; Buvat, S.; Tabbagh, A.</p> <p>2012-12-01</p> <p>Both electrical conductivity and dielectric permittivity of soil are influenced by its water content. Dielectric permittivity is usually measured in the high <span class="hlt">frequency</span> range, using GPR or TDR, where the sensitivity to water content is high. However, its evaluation is limited by a low investigation depth, especially for clay rich soils. Electrical conductivity is closely related not only to soil water content, but also to clay content and soil structure. A simultaneous estimation of these electrical parameters can allow the mapping of soil water content <span class="hlt">variations</span> for an investigation depth close to 1m. In order to estimate simultaneously both soil electrical conductivity and dielectric permittivity, an electromagnetic device working in the medium <span class="hlt">frequency</span> range (between 100 kHz and 10 MHz) has been designed. We adopted Slingram geometry for the EM prototype: its PERP configuration (vertical transmission loop Tx and horizontal measuring loop Rx) was defined using 1D ground models. As the required investigation depth is around 1m, the coil spacing was fixed to 1.2m. This prototype works in a <span class="hlt">frequency</span> range between 1 and 5 MHz. After calibration, we tested the response of prototype to objects with known properties. The first in situ measurements were led on experimental sites with different types of soils and different water content <span class="hlt">variations</span> (artificially created or natural): sandy alluvium on a plot of INRA (French National Institute for Agricultural Research) in Orléans (Centre, France), a clay-loam soil on an experimental site in Estrée-Mons (Picardie, France) and fractured limestone at the vicinity of Grand (Vosges, France). In the case of the sandy alluvium, the values of dielectric permittivity measured are close to those of HF permittivity and allow the use of existing theoretical models to determine the soil water content. For soils containing higher amount of clay, the coupled information brought by the electrical conductivity and the dielectric</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=303213','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=303213"><span>A surface epitope undergoing high-<span class="hlt">frequency</span> phase <span class="hlt">variation</span> is shared by Mycoplasma gallisepticum and Mycoplasma bovis.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yogev, D; Menaker, D; Strutzberg, K; Levisohn, S; Kirchhoff, H; Hinz, K H; Rosengarten, R</p> <p>1994-01-01</p> <p>We have recently reported that three distinct size- and phase-variable surface lipoproteins (Vsps) of the bovine pathogen Mycoplasma bovis possess a common epitope recognized by monoclonal antibody 1E5. In the present study, we show that this epitope is also present on a size-variant protein (PvpA) of the avian pathogen Mycoplasma gallisepticum. Application of monoclonal antibody 1E5 in Western immunoblot analysis of Triton X-114 phase-fractionated proteins and in colony immunoblots, as well as in trypsin and carboxypeptidase digestion experiments, has demonstrated that (i) PvpA is an integral membrane protein with a free C terminus, (ii) the shared epitope is surface exposed, and (iii) PvpA is subjected to high-<span class="hlt">frequency</span> phase <span class="hlt">variation</span> in expression. By using serum antibodies from M. gallisepticum-infected chickens, we were able to demonstrate the immunogenic nature of PvpA and identify three additional highly immunogenic Triton X-114 phase proteins (p67, p72, and p75) also undergoing high-<span class="hlt">frequency</span> phase <span class="hlt">variation</span> spontaneously and independently. Metabolic labeling experiments with [14C]palmitate and [14C]oleate revealed that PvpA, in contrast to p67, p72, and p75, is not lipid modified. Southern blot hybridization with restriction fragments carrying the pvpA gene of M. gallisepticum or the vspA gene of M. bovis against digested genomic DNA of the two Mycoplasma species indicated the absence of genetic relatedness between the pvpA and vspA genes. The apparent complexity of the antigenic <span class="hlt">variation</span> phenomenon in M. gallisepticum is discussed. Images PMID:7523302</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AAS...21840605D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AAS...21840605D"><span>On the <span class="hlt">Frequency</span> of Additional Planets in Short Period Hot Jupiter Systems from Transit Timing <span class="hlt">Variations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dittmann, Jason; Close, L.; Scuderi, L.</p> <p>2011-05-01</p> <p>The large number of hot Jupiter planets allows one to probe these systems for additional unseen planets via transit timing <span class="hlt">variations</span> (TTVs). Even relatively small terrestrial planets, when placed in an energetically favorable mean motion resonance (MMR), can cause detectable TTVs with an amplitude of several minutes (Holman and Murray 2005, Agol et al. 2005). In an effort to discover and characterize such companions, we have embarked on a systematic study of known transiting hot Jupiters, utilizing the 1.55 meter Kuiper telescope on Mt. Bigelow to measure multiple individual transits in an observing season to within 30 second precision, and constrain the nature of any planetary companions. Here, we present current and preliminary results on this study, and show that the systems HAT-P-5, HAT- P-6, HAT-P-8, HAT-P-9, WASP-11/HAT-P-10, HAT-P-11, TrES-2, and WASP-10 do not contain small mass companions in MMRs, or moderate mass companions in close enough proximity to induce TTVs on the order of 1.5 minutes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22952449','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22952449"><span>Telomere length affects the <span class="hlt">frequency</span> and mechanism of antigenic <span class="hlt">variation</span> in Trypanosoma brucei.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hovel-Miner, Galadriel A; Boothroyd, Catharine E; Mugnier, Monica; Dreesen, Oliver; Cross, George A M; Papavasiliou, F Nina</p> <p>2012-01-01</p> <p>Trypanosoma brucei is a master of antigenic <span class="hlt">variation</span> and immune response evasion. Utilizing a genomic repertoire of more than 1000 Variant Surface Glycoprotein-encoding genes (VSGs), T. brucei can change its protein coat by "switching" from the expression of one VSG to another. Each active VSG is monoallelically expressed from only one of approximately 15 subtelomeric sites. Switching VSG expression occurs by three predominant mechanisms, arguably the most significant of which is the non-reciprocal exchange of VSG containing DNA by duplicative gene conversion (GC). How T. brucei orchestrates its complex switching mechanisms remains to be elucidated. Recent work has demonstrated that an exogenous DNA break in the active site could initiate a GC based switch, yet the source of the switch-initiating DNA lesion under natural conditions is still unknown. Here we investigated the hypothesis that telomere length directly affects VSG switching. We demonstrate that telomerase deficient strains with short telomeres switch more frequently than genetically identical strains with long telomeres and that, when the telomere is short, switching preferentially occurs by GC. Our data supports the hypothesis that a short telomere at the active VSG expression site results in an increase in subtelomeric DNA breaks, which can initiate GC based switching. In addition to their significance for T. brucei and telomere biology, the findings presented here have implications for the many diverse pathogens that organize their antigenic genes in subtelomeric regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23905281','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23905281"><span>Effects of fundamental <span class="hlt">frequency</span> and duration <span class="hlt">variation</span> on the perception of South Kyungsang Korean tones.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chang, Seung-Eun</p> <p>2013-06-01</p> <p>The perception of lexical tones is addressed through research on South Kyungsang Korean, spoken in the southeastern part of Korea. Based on an earlier production study (Chang, 2008a, 2008b), a categorization experiment was conducted to determine the perceptually salient aspects of the perceptual nature of a high tone and a rising tone. The experiment tested the perception of isolated synthetic stimuli, in which the crucial acoustic parameters (i.e., timing of F0 peak, initial F0, and syllable duration) were systematically manipulated. The results are generally consistent with the previous production data, showing that these acoustic cues contribute to the perception of two tones, a high tone and a rising tone. The stimulus tends to be identified as a rising tone if the F0 peak is late in the syllable, the initial F0 is low, and the syllable is long, while the stimulus tends to be identified as a high tone if the F0 peak is early in the syllable, the initial F0 is high, and the duration is short. Each of these three parameters, although necessary, did not contribute equally to the perception of tone contrast. Between-subject <span class="hlt">variation</span>, according to the participant's gender and language background, is also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70176033','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70176033"><span>Spatial-temporal <span class="hlt">variation</span> of low-<span class="hlt">frequency</span> earthquake bursts near Parkfield, California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wu, Chunquan; Guyer, Robert; Shelly, David R.; Trugman, D.; Frank, William; Gomberg, Joan S.; Johnson, P.</p> <p>2015-01-01</p> <p>Tectonic tremor (TT) and low-<span class="hlt">frequency</span> earthquakes (LFEs) have been found in the deeper crust of various tectonic environments globally in the last decade. The spatial-temporal behaviour of LFEs provides insight into deep fault zone processes. In this study, we examine recurrence times from a 12-yr catalogue of 88 LFE families with ∼730 000 LFEs in the vicinity of the Parkfield section of the San Andreas Fault (SAF) in central California. We apply an automatic burst detection algorithm to the LFE recurrence times to identify the clustering behaviour of LFEs (LFE bursts) in each family. We find that the burst behaviours in the northern and southern LFE groups differ. Generally, the northern group has longer burst duration but fewer LFEs per burst, while the southern group has shorter burst duration but more LFEs per burst. The southern group LFE bursts are generally more correlated than the northern group, suggesting more coherent deep fault slip and relatively simpler deep fault structure beneath the locked section of SAF. We also found that the 2004 Parkfield earthquake clearly increased the number of LFEs per burst and average burst duration for both the northern and the southern groups, with a relatively larger effect on the northern group. This could be due to the weakness of northern part of the fault, or the northwesterly rupture direction of the Parkfield earthquake.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70026885','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70026885"><span>Spatial <span class="hlt">variations</span> in the <span class="hlt">frequency</span>-magnitude distribution of earthquakes at Mount Pinatubo volcano</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sanchez, J.J.; McNutt, S.R.; Power, J.A.; Wyss, M.</p> <p>2004-01-01</p> <p>The <span class="hlt">frequency</span>-magnitude distribution of earthquakes measured by the b-value is mapped in two and three dimensions at Mount Pinatubo, Philippines, to a depth of 14 km below the summit. We analyzed 1406 well-located earthquakes with magnitudes MD ???0.73, recorded from late June through August 1991, using the maximum likelihood method. We found that b-values are higher than normal (b = 1.0) and range between b = 1.0 and b = 1.8. The computed b-values are lower in the areas adjacent to and west-southwest of the vent, whereas two prominent regions of anomalously high b-values (b ??? 1.7) are resolved, one located 2 km northeast of the vent between 0 and 4 km depth and a second located 5 km southeast of the vent below 8 km depth. The statistical differences between selected regions of low and high b-values are established at the 99% confidence level. The high b-value anomalies are spatially well correlated with low-velocity anomalies derived from earlier P-wave travel-time tomography studies. Our dataset was not suitable for analyzing changes in b-values as a function of time. We infer that the high b-value anomalies around Mount Pinatubo are regions of increased crack density, and/or high pore pressure, related to the presence of nearby magma bodies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007EP%26S...59..221L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007EP%26S...59..221L"><span>Spatial <span class="hlt">variations</span> in the <span class="hlt">frequency</span>-magnitude distribution of earthquakes in the southwestern Okinawa Trough</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, J.-Y.; Sibuet, J.-C.; Lee, C.-S.; Hsu, S.-K.; Klingelhoefer, F.</p> <p>2007-04-01</p> <p>The relations between the <span class="hlt">frequency</span> of occurrence and the magnitude of earthquakes are established in the southern Okinawa Trough for 2823 relocated earthquakes recorded during a passive ocean bottom seismometer experiment. Three high b-values areas are identified: (1) for an area offshore of the Ilan Plain, south of the andesitic Kueishantao Island from a depth of 50 km to the surface, thereby confirming the subduction component of the island andesites; (2) for a body lying along the 123.3°E meridian at depths ranging from 0 to 50 km that may reflect the high temperature inflow rising up from a slab tear; (3) for a third cylindrical body about 15 km in diameter beneath the Cross Backarc Volcanic Trail, at depths ranging from 0 to 15 km. This anomaly might be related to the presence of a magma chamber at the base of the crust already evidenced by tomographic and geochemical results. The high b-values are generally linked to magmatic and geothermal activities, although most of the seismicity is linked to normal faulting processes in the southern Okinawa Trough.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4795233','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4795233"><span>The relationship between surname <span class="hlt">frequency</span> and Y chromosome <span class="hlt">variation</span> in Spain</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Martinez-Cadenas, Conrado; Blanco-Verea, Alejandro; Hernando, Barbara; Busby, George BJ; Brion, Maria; Carracedo, Angel; Salas, Antonio; Capelli, Cristian</p> <p>2016-01-01</p> <p>In most societies, surnames are passed down from fathers to sons, just like the Y chromosome. It follows that, theoretically, men sharing the same surnames would also be expected to share related Y chromosomes. Previous investigations have explored such relationships, but so far, the only detailed studies that have been conducted are on samples from the British Isles. In order to provide additional insights into the correlation between surnames and Y chromosomes, we focused on the Spanish population by analysing Y chromosomes from 2121 male volunteers representing 37 surnames. The results suggest that the degree of coancestry within Spanish surnames is highly dependent on surname <span class="hlt">frequency</span>, in overall agreement with British but not Irish surname studies. Furthermore, a reanalysis of comparative data for all three populations showed that Irish surnames have much greater and older surname descent clusters than Spanish and British ones, suggesting that Irish surnames may have considerably earlier origins than Spanish or British ones. Overall, despite closer geographical ties between Ireland and Britain, our analysis points to substantial similarities in surname origin and development between Britain and Spain, while possibly hinting at unique demographic or social events shaping Irish surname foundation and development. PMID:25898922</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA218270','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA218270"><span>Effect of <span class="hlt">Variation</span> in the Burst Mode and Carrier <span class="hlt">Frequency</span> of High Intensity Electrical Stimulation on Muscle Fatigue and Pain Perception of Healthy Subjects</span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>1988-10-22</p> <p>MVC; ( c ) Subjects pain tolerance is contingent upon the stimulating <span class="hlt">frequency</span> and the amplitude of stimulation. <span class="hlt">Variations</span> in either burst mode or...Body Weight and Force Data ..... ............. .132 C . Suoject Pain Ratings for all Combinations of Bursts and Carrier <span class="hlt">Frequencies</span>...work supports the "size principle’ espoused by Henneman (1965) and confirmed by electromyographic studies using fine wire electrodes (Hannez, 1974</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_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" 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_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</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="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26892980','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26892980"><span>Genetic <span class="hlt">variation</span> <span class="hlt">frequencies</span> in Wilms' tumor: A meta-analysis and systematic review.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Deng, Changkai; Dai, Rong; Li, Xuliang; Liu, Feng</p> <p>2016-05-01</p> <p>Over the last few decades, numerous biomarkers in Wilms' tumor have been confirmed and shown <span class="hlt">variations</span> in prevalence. Most of these studies were based on small sample sizes. We carried out a meta-analysis of the research published from 1992 to 2015 to obtain more precise and comprehensive outcomes for genetic tests. In the present study, 70 out of 5175 published reports were eligible for the meta-analysis, which was carried out using Stata 12.0 software. Pooled prevalence for gene mutations WT1, WTX, CTNNB1, TP53, MYCN, DROSHA, and DGCR8 was 0.141 (0.104, 0.178), 0.147 (0.110, 0.184), 0.140 (0.100, 0.190), 0.410 (0.214, 0.605), 0.071 (0.041, 0.100), 0.082 (0.048, 0.116), and 0.036 (0.026, 0.046), respectively. Pooled prevalence of loss of heterozygosity at 1p, 11p, 11q, 16q, and 22q was 0.109 (0.084, 0.133), 0.334 (0.295, 0.373), 0.199 (0.146, 0.252), 0.151 (0.129, 0.172), and 0.148 (0.108, 0.189), respectively. Pooled prevalence of 1q and chromosome 12 gain was 0.218 (0.161, 0.275) and 0.273 (0.195, 0.350), respectively. The limited prevalence of currently known genetic alterations in Wilms' tumors indicates that significant drivers of initiation and progression remain to be discovered. Subgroup analyses indicated that ethnicity may be one of the sources of heterogeneity. However, in meta-regression analyses, no study-level characteristics of indicators were found to be significant. In addition, the findings of our sensitivity analysis and possible publication bias remind us to interpret results with caution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19320169','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19320169"><span>Time-<span class="hlt">frequency</span> analysis of beach bacteria <span class="hlt">variations</span> and its implication for recreational water quality modeling.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ge, Zhongfu; Frick, Walter E</p> <p>2009-02-15</p> <p>This paper exploited the potential of the wavelet analysis in resolving beach bacteria concentration and candidate explanatory variables across multiple time scales with temporal information preserved. The wavelet transform of E. coli concentration and its explanatory variables observed at Huntington Beach, Ohio in 2006 exhibited well-defined patterns of different time scales, phases, and durations, which cannot be clearly shown in conventional time-domain analyses. If linear regression modeling is to be used for the ease of implementation and interpretation,the wavelet-transformed regression model reveals that low model residual can be realized through matching major patterns and their phase angles between E. coli concentration and its explanatory variables. The property of pattern matching for linear regression models can be adopted as a criterion for choosing useful predictors, while phase matching further explains why intuitively good variables such as wave height and onshore wind speed were excluded from the optimal models by model selection processes in Frick et al. (Environ. Sci. Technol. 2008, 42,4818-4824). The phase angles defined by the wavelet analysis in the time-<span class="hlt">frequency</span> domain can help identify the physical processes and interactions occurring between bacteria concentration and its explanatory variables. It was deduced, for this particular case, that wind events resulted in elevated E. coli concentration, wave height, and turbidity at the beach with a periodicity of 7-8 days. Wind events also brought about increased beach bacteria concentrations through large-scale current circulations in the lake with a period of 21 days. The time length for linear regression models with statistical robustness can also be deduced from the periods of the major patterns in bacteria concentration and explanatory variables, which explains and supplements the modeling efforts performed in (1).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3389337','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3389337"><span><span class="hlt">Variations</span> in Dream Recall <span class="hlt">Frequency</span> and Dream Theme Diversity by Age and Sex</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nielsen, Tore</p> <p>2012-01-01</p> <p>We assessed dream recall <span class="hlt">frequency</span> (DRF) and dream theme diversity (DTD) with an internet questionnaire among a cohort of 28,888 male and female participants aged 10–79 years in a cross-sectional design. DRF increased from adolescence (ages 10–19) to early adulthood (20–29) and then decreased again for the next 20 years. The nature of this decrease differed for males and females. For males, it began earlier (30–39), proceeded more gradually, and reached a nadir earlier (40–49) than it did for females. For females, it began later (40–49), dropped more abruptly, and reached nadir later (50–59). Marked sex differences were observed for age strata 10–19 through 40–49 and year-by-year analyses estimated the window for these differences to be more precisely from 14 to 44 years. DTD decreased linearly with age for both sexes up to 50–59 and then dropped even more sharply for 60–79. There was a sex difference favoring males on this measure but only for ages 10–19. Findings replicate, in a single sample, those from several previous studies showing an increase in DRF from adolescence to early adulthood, a subsequent decrease primarily in early and middle adulthood, and different patterns of age-related decrease in the two sexes. Age-related changes in sleep structure, such as decreasing %REM sleep which parallel the observed dream recall changes, might help explain these findings, but these sleep changes are much smaller and more gradual in nature. Changes in the phase and amplitude of circadian rhythms of REM propensity and generational differences in life experiences may also account for some part of the findings. That decreases in DTD parallel known age-related decreases in episodic and autobiographical memory may signify that this new diversity measure indexes an aspect of autobiographical memory that also influences dream recall. PMID:22783222</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=gay+AND+marriage+AND+children&pg=2&id=EJ325018','ERIC'); return false;" href="http://eric.ed.gov/?q=gay+AND+marriage+AND+children&pg=2&id=EJ325018"><span>Marital Discord and Marital <span class="hlt">Separation</span>: A County Survey.</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>Kitson, Gay C.</p> <p>1985-01-01</p> <p>Explored the <span class="hlt">frequency</span> of marital <span class="hlt">separations</span> of 48 hours or more due to marital discord in Cuyahoga County, Ohio, residents (N=1,101). Results indicated one in six couples is likely to <span class="hlt">separate</span> at some point in their relationship. Income and children account for much of the <span class="hlt">variation</span> between race, sex, and <span class="hlt">separations</span>. (Author/BL)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17086451','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17086451"><span>The <span class="hlt">frequency</span> of eubacterium-to-eukaryote lateral gene transfers shows significant cross-taxa <span class="hlt">variation</span> within amoebozoa.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Watkins, Russell F; Gray, Michael W</p> <p>2006-12-01</p> <p>Single-celled bacterivorous eukaryotes offer excellent test cases for evaluation of the <span class="hlt">frequency</span> of prey-to-predator lateral gene transfer (LGT). Here we use analysis of expressed sequence tag (EST) data sets to quantify the extent of LGT from eubacteria to two amoebae, Acanthamoeba castellanii and Hartmannella vermiformis. Stringent screening for LGT proceeded in several steps intended to enrich for authentic events while at the same time minimizing the incidence of false positives due to factors such as limitations in database coverage and ancient paralogy. The results were compared with data obtained when the same methodology was applied to EST libraries from a number of other eukaryotic taxa. Significant differences in the extent of apparent eubacterium-to-eukaryote LGT were found between taxa. Our results indicate that there may be substantial inter-taxon <span class="hlt">variation</span> in the number of LGT events that become fixed even between amoebozoan species that have similar feeding modalities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16241387','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16241387"><span>Autoregressive processes with anomalous scaling behavior: applications to high-<span class="hlt">frequency</span> <span class="hlt">variations</span> of a stock market index.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dose, Christian; Porto, Markus; Roman, H Eduardo</p> <p>2003-06-01</p> <p>We employ autoregressive conditional heteroskedasticity processes to model the probability distribution function (PDF) of high-<span class="hlt">frequency</span> relative <span class="hlt">variations</span> of the Standard & Poors 500 market index data, obtained at the time horizon of 1 min. The model reproduces quantitatively the shape of the PDF, characterized by a Lévy-type power-law decay around its center, followed by a crossover to a faster decay at the tails. Furthermore, it is able to reproduce accurately the anomalous decay of the central part of the PDF at larger time horizons and, by the introduction of a short-range memory, also the crossover behavior of the corresponding standard deviations and the time scale of the exponentially decaying autocorrelation function of returns displayed by the empirical data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1514246J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1514246J"><span>High <span class="hlt">frequency</span> <span class="hlt">variations</span> of the main magnetic field: convergence of observations and theory (Petrus Peregrinus Medal Lecture)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jault, Dominique</p> <p>2013-04-01</p> <p>Understanding the main magnetic field <span class="hlt">variations</span> has been hindered by the discrepancy between the periods (from months to years) of the simplest linear wave phenomena and the relatively long time intervals (10 to 100 years) over which magnetic field changes can be confidently monitored. A theoretical description of short-period waves within the Earth's fluid core is at hand. Quasi-geostrophic inertial waves (akin to Rossby waves in the atmosphere) are slightly modified in the presence of magnetic fields and torsional oscillations consist of differential motion between coaxial rigid cylindrical annuli. Torsional oscillations are sensitive to the whole magnetic field that they shear in the course of their propagation. From their modelling, we have thus gained an estimate for the magnetic field strength in the core interior. There is now ongoing work to extend the theoretical framework to longer times. Furthermore, data collected from the Swarm constellation of three satellites to be launched this year by ESA will permit to better <span class="hlt">separate</span> the internal and external magnetic signals. We may thus dream to detect quasi-geostrophic inertial waves. As the spectral ranges of theoretical models and observations begin to overlap, we can now go beyond the understanding of the magnetic field <span class="hlt">variations</span> as the juxtaposition of partial models, arranged as a set of nested Matryoshka dolls. This talk will give illustrations for this statement, among which the question of induction in the lower mantle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CSR...122....1O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CSR...122....1O"><span>High-<span class="hlt">frequency</span> sea level <span class="hlt">variations</span> and implications for coastal flooding: A case study of the Solent, UK</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ozsoy, Ozgun; Haigh, Ivan D.; Wadey, Matthew P.; Nicholls, Robert J.; Wells, Neil C.</p> <p>2016-07-01</p> <p>This study examines the occurrence and characteristics of high-<span class="hlt">frequency</span> (<6 h) sea level <span class="hlt">variations</span> in the Solent, UK - a mesotidal estuarine strait located in the central English Channel. A 14-year time series (2000-2013) of sea level observations sampled at 15-min intervals from the Southampton tide gauge was analyzed. The 8 highest-energy events have a mean amplitude of approximately 0.6 m and a dominant period of around 4 h. These events correspond with periods of enhanced meteorological activity, namely a marked reduction in air pressure and onset of strong southwesterly-southeasterly winds. Sea level observations from tide gauges around the Solent and the wider English Channel region (23 in total) were used to assess the spatial characteristics of these events. Analysis of time series and phase information indicates the occurrence of standing waves oscillating across the English Channel between southern England and northern France. This study provides a unique example of standing waves generated by extra-tropical cyclones over a large basin (the English Channel) with implications for flood inundation. The event of 28th October 2013 - the highest-amplitude (1.16 m) event in the record - was associated with minor coastal flooding at Yarmouth, Isle of Wight. This flood occurred during a neap tide, when such events are widely thought to be impossible. Hence, our findings emphasize the relevance of high-<span class="hlt">frequency</span> sea level variability for regional sea level forecasting and flood risk management.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21259663','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21259663"><span><span class="hlt">Variational</span> derivation of the dispersion relation of kinetic coherent modes in the acoustic <span class="hlt">frequency</span> range in tokamaks</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nguyen, C.; Garbet, X.; Smolyakov, A. I.</p> <p>2008-11-15</p> <p>In the present paper, we compare two modes with <span class="hlt">frequencies</span> belonging to the acoustic <span class="hlt">frequency</span> range: the geodesic acoustic mode (GAM) and the Beta Alfven eigenmode (BAE). For this, a <span class="hlt">variational</span> gyrokinetic energy principle coupled to a Fourier sidebands expansion is developed. High order finite Larmor radius and finite orbit width effects are kept. Their impact on the mode structures and on the Alfven spectrum is calculated and discussed. We show that in a local analysis, the degeneracy of the electrostatic GAM and the BAE dispersion relations is verified to a high order and based in particular on a local poloidal symmetry of the two modes. When a more global point of view is taken, and the full radial structures of the modes are computed, differences appear. The BAE structure is shown to have an enforced localization, and to possibly connect to a large magnetohydrodynamic structure. On the contrary, the GAM is seen to have a wavelike, nonlocalized structure, as long as standard slowly varying monotonic profiles are considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/3352638','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/3352638"><span>Effect of X-ray and ethylnitrosourea exposures <span class="hlt">separated</span> by 24 h on specific-locus mutation <span class="hlt">frequency</span> in mouse stem-cell spermatogonia.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Russell, W L; Carpenter, D A; Hitotsumachi, S</p> <p>1988-04-01</p> <p>Specific-locus mutation <span class="hlt">frequencies</span> in mouse stem-cell spermatogonia were determined in 3 experiments in which mature male mice were exposed to 100,m 300, or 500 R of X-rays followed, 24 h later, by intraperitoneal injection of 100 mg/kg of ethylnitrosourea (ENU). The purpose was to find out if the mutation <span class="hlt">frequencies</span> would be augmented over those expected on the basis of additivity of the effects of the <span class="hlt">separate</span> treatments. Such augmentation had been observed in earlier work in which exposure to 100 or 500 R of X-rays was followed 24 h later by a second exposure of 500 R. No augmentation was observed for X-rays followed by ENU. The mutation <span class="hlt">frequencies</span> in all 3 experiments actually fell below those expected on the basis of additivity, although the reductions were not statistically significant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22492970','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22492970"><span>Multi-<span class="hlt">frequency</span> inversion-charge pumping for charge <span class="hlt">separation</span> and mobility analysis in high-k/InGaAs metal-oxide-semiconductor field-effect transistors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Djara, V.; Cherkaoui, K.; Negara, M. A.; Hurley, P. K.</p> <p>2015-11-28</p> <p>An alternative multi-<span class="hlt">frequency</span> inversion-charge pumping (MFICP) technique was developed to directly <span class="hlt">separate</span> the inversion charge density (N{sub inv}) from the trapped charge density in high-k/InGaAs metal-oxide-semiconductor field-effect transistors (MOSFETs). This approach relies on the fitting of the <span class="hlt">frequency</span> response of border traps, obtained from inversion-charge pumping measurements performed over a wide range of <span class="hlt">frequencies</span> at room temperature on a single MOSFET, using a modified charge trapping model. The obtained model yielded the capture time constant and density of border traps located at energy levels aligned with the InGaAs conduction band. Moreover, the combination of MFICP and pulsed I{sub d}-V{sub g} measurements enabled an accurate effective mobility vs N{sub inv} extraction and analysis. The data obtained using the MFICP approach are consistent with the most recent reports on high-k/InGaAs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014A%26A...570A.100S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014A%26A...570A.100S"><span>Revisiting CoRoT RR Lyrae stars: detection of period doubling and temporal <span class="hlt">variation</span> of additional <span class="hlt">frequencies</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Szabó, R.; Benkő, J. M.; Paparó, M.; Chapellier, E.; Poretti, E.; Baglin, A.; Weiss, W. W.; Kolenberg, K.; Guggenberger, E.; Le Borgne, J.-F.</p> <p>2014-10-01</p> <p>Context. High-precision, space-based photometric missions like CoRoT and Kepler have revealed new and surprising phenomena in classical variable stars. Such discoveries were the period doubling in RR Lyrae stars and the frequent occurrence of additional periodicities some of which can be explained by radial overtone modes, but others are discordant with the radial eigenfrequency spectrum. Aims: We search for signs of period doubling in CoRoT RR Lyrae stars. The occurrence of this dynamical effect in modulated RR Lyrae stars might help us to gain more information about the mysterious Blazhko effect. The temporal variability of the additional <span class="hlt">frequencies</span> in representatives of all subtypes of RR Lyrae stars is also investigated. Methods: We preprocess CoRoT light curves by applying trend and jump correction and outlier removal. Standard Fourier technique is used to analyze the <span class="hlt">frequency</span> content of our targets and follow the time-dependent phenomena. Results: The most comprehensive collection of CoRoT RR Lyrae stars, including new discoveries is presented and analyzed. We found alternating maxima and in some cases half-integer <span class="hlt">frequencies</span> in four CoRoT Blazhko RR Lyrae stars, as clear signs of the presence of period doubling. This reinforces that period doubling is an important ingredient for understanding the Blazhko effect - a premise we derived previously from the Kepler RR Lyrae sample. As expected, period doubling is detectable only for short time intervals in most modulated RRab stars. Our results show that the temporal variability of the additional <span class="hlt">frequencies</span> in all RR Lyrae subtypes is ubiquitous. The ephemeral nature and the highly variable amplitude of these <span class="hlt">variations</span> suggest a complex underlying dynamics of and an intricate interplay between radial and possibly nonradial modes in RR Lyrae stars. The omnipresence of additional modes in all types of RR Lyrae - except in non-modulated RRab stars - implies that asteroseismology of these objects should be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JAP...106c3308X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JAP...106c3308X"><span>High efficiency annular magnetically insulated line oscillator-transit time oscillator with three <span class="hlt">separate</span> <span class="hlt">frequencies</span> in three bands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiao, Renzhen; Sun, Jun; Chen, Changhua; Zhang, Yongpeng; Shao, Hao</p> <p>2009-08-01</p> <p>To increase the efficiency of the magnetically insulated line oscillator (MILO) and expand its <span class="hlt">frequency</span> band, a coaxial transit time oscillator (TTO) is introduced to use the load currents of an annular MILO, called the annular MILO-TTO, which comprises an inward-emitting MILO, an outward-emitting MILO, and a coaxial TTO. In simulation, when the input power is 78 GW and the diode voltage is 520 kV, three microwaves with powers of 3.2, 9.6, and 7.0 GW are generated, with a total efficiency of 25.4%, in the inward-emitting MILO, the outward-emitting MILO, and the coaxial TTO, and the <span class="hlt">frequencies</span> are 1.7, 3.3, and 4.2 GHz, corresponding to L, S, and C bands, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApPhB.122..203K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApPhB.122..203K"><span>Evaluation of <span class="hlt">variation</span> in ( m_p/m_e) from the <span class="hlt">frequency</span> difference between the 15N2+ and 87Sr transitions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kajita, Masatoshi</p> <p>2016-07-01</p> <p>The uncertainty of the 87Sr1 S0-3 P0 transition <span class="hlt">frequency</span> (429 THz) has been reduced to the level of 10^{-18}. Also, the 15N2+ Q(0) vibrational transition <span class="hlt">frequency</span> is expected to be measured with an uncertainty of 10^{-17} , and the v = 0-7 transition <span class="hlt">frequency</span> (422 THz) is close to the 87Sr transition <span class="hlt">frequency</span>. In this paper, we propose a test for the <span class="hlt">variation</span> in the proton-to-electron mass ratio μ via precise measurement of the difference (f_d=7 THz) between these transition <span class="hlt">frequencies</span>. By measuring f_d within the uncertainty of 10^{-16}, a <span class="hlt">variation</span> in μ of 4 × 10^{-18} can be detected. The 15N2+ v =0 -7 Q(0) transition <span class="hlt">frequency</span> is free from Zeeman and electric quadrupole shifts. The dc Stark coefficient is about 0.2 mHz/(V/cm)2, and the measurement of f_d with an uncertainty lower than 10^{-16} appears to be attainable using molecular ions in a string crystal. The 15N2+ transition <span class="hlt">frequency</span> is observed via the two-photon excitation of a laser with a wavelength of 1422 nm (laser A). Another laser with a wavelength of 1396 nm (laser B) is used as a 87Sr clock laser after <span class="hlt">frequency</span> doubling. The <span class="hlt">frequency</span> difference between lasers A and B (3.5 THz) should be measured using a <span class="hlt">frequency</span> comb. Lasers A and B can be transferred to another laboratory via an optical fiber. Therefore, a sensitive test of the <span class="hlt">variation</span> in μ can be performed in cooperation between two distant laboratories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27446671','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27446671"><span>Artificial neural networks for retrieving absorption and reduced scattering spectra from <span class="hlt">frequency</span>-domain diffuse reflectance spectroscopy at short source-detector <span class="hlt">separation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Yu-Wen; Chen, Chien-Chih; Huang, Po-Jung; Tseng, Sheng-Hao</p> <p>2016-04-01</p> <p>Diffuse reflectance spectroscopy (DRS) based on the <span class="hlt">frequency</span>-domain (FD) technique has been employed to investigate the optical properties of deep tissues such as breast and brain using source to detector <span class="hlt">separation</span> up to 40 mm. Due to the modeling and system limitations, efficient and precise determination of turbid sample optical properties from the FD diffuse reflectance acquired at a source-detector <span class="hlt">separation</span> (SDS) of around 1 mm has not been demonstrated. In this study, we revealed that at SDS of 1 mm, acquiring FD diffuse reflectance at multiple <span class="hlt">frequencies</span> is necessary for alleviating the influence of inevitable measurement uncertainty on the optical property recovery accuracy. Furthermore, we developed artificial neural networks (ANNs) trained by Monte Carlo simulation generated databases that were capable of efficiently determining FD reflectance at multiple <span class="hlt">frequencies</span>. The ANNs could work in conjunction with a least-square optimization algorithm to rapidly (within 1 second), accurately (within 10%) quantify the sample optical properties from FD reflectance measured at SDS of 1 mm. In addition, we demonstrated that incorporating the steady-state apparatus into the FD DRS system with 1 mm SDS would enable obtaining broadband absorption and reduced scattering spectra of turbid samples in the wavelength range from 650 to 1000 nm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4929657','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4929657"><span>Artificial neural networks for retrieving absorption and reduced scattering spectra from <span class="hlt">frequency</span>-domain diffuse reflectance spectroscopy at short source-detector <span class="hlt">separation</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>Chen, Yu-Wen; Chen, Chien-Chih; Huang, Po-Jung; Tseng, Sheng-Hao</p> <p>2016-01-01</p> <p>Diffuse reflectance spectroscopy (DRS) based on the <span class="hlt">frequency</span>-domain (FD) technique has been employed to investigate the optical properties of deep tissues such as breast and brain using source to detector <span class="hlt">separation</span> up to 40 mm. Due to the modeling and system limitations, efficient and precise determination of turbid sample optical properties from the FD diffuse reflectance acquired at a source-detector <span class="hlt">separation</span> (SDS) of around 1 mm has not been demonstrated. In this study, we revealed that at SDS of 1 mm, acquiring FD diffuse reflectance at multiple <span class="hlt">frequencies</span> is necessary for alleviating the influence of inevitable measurement uncertainty on the optical property recovery accuracy. Furthermore, we developed artificial neural networks (ANNs) trained by Monte Carlo simulation generated databases that were capable of efficiently determining FD reflectance at multiple <span class="hlt">frequencies</span>. The ANNs could work in conjunction with a least-square optimization algorithm to rapidly (within 1 second), accurately (within 10%) quantify the sample optical properties from FD reflectance measured at SDS of 1 mm. In addition, we demonstrated that incorporating the steady-state apparatus into the FD DRS system with 1 mm SDS would enable obtaining broadband absorption and reduced scattering spectra of turbid samples in the wavelength range from 650 to 1000 nm. PMID:27446671</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013QSRv...80..112W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013QSRv...80..112W"><span>Holocene flood <span class="hlt">frequency</span> across the Central Alps - solar forcing and evidence for <span class="hlt">variations</span> in North Atlantic atmospheric circulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wirth, Stefanie B.; Glur, Lukas; Gilli, Adrian; Anselmetti, Flavio S.</p> <p>2013-11-01</p> <p>The <span class="hlt">frequency</span> of large-scale heavy precipitation events in the European Alps is expected to undergo substantial changes with current climate change. Hence, knowledge about the past natural variability of floods caused by heavy precipitation constitutes important input for climate projections. We present a comprehensive Holocene (10,000 years) reconstruction of the flood <span class="hlt">frequency</span> in the Central European Alps combining 15 lacustrine sediment records. These records provide an extensive catalog of flood deposits, which were generated by flood-induced underflows delivering terrestrial material to the lake floors. The multi-archive approach allows suppressing local weather patterns, such as thunderstorms, from the obtained climate signal. We reconstructed mainly late spring to fall events since ice cover and precipitation in form of snow in winter at high-altitude study sites do inhibit the generation of flood layers. We found that flood <span class="hlt">frequency</span> was higher during cool periods, coinciding with lows in solar activity. In addition, flood occurrence shows periodicities that are also observed in reconstructions of solar activity from 14C and 10Be records (2500-3000, 900-1200, as well as of about 710, 500, 350, 208 (Suess cycle), 150, 104 and 87 (Gleissberg cycle) years). As atmospheric mechanism, we propose an expansion/shrinking of the Hadley cell with increasing/decreasing air temperature, causing dry/wet conditions in Central Europe during phases of high/low solar activity. Furthermore, differences between the flood patterns from the Northern Alps and the Southern Alps indicate changes in North Atlantic circulation. Enhanced flood occurrence in the South compared to the North suggests a pronounced southward position of the Westerlies and/or blocking over the northern North Atlantic, hence resembling a negative NAO state (most distinct from 4.2 to 2.4 kyr BP and during the Little Ice Age). South-Alpine flood activity therefore provides a qualitative record of <span class="hlt">variations</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PMB....59.6019S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PMB....59.6019S"><span><span class="hlt">Separating</span> components of <span class="hlt">variation</span> in measurement series using maximum likelihood estimation. Application to patient position data in radiotherapy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sage, J. P.; Mayles, W. P. M.; Mayles, H. M.; Syndikus, I.</p> <p>2014-10-01</p> <p>Maximum likelihood estimation (MLE) is presented as a statistical tool to evaluate the contribution of measurement error to any measurement series where the same quantity is measured using different independent methods. The technique was tested against artificial data sets; generated for values of underlying <span class="hlt">variation</span> in the quantity and measurement error between 0.5 mm and 3 mm. In each case the simulation parameters were determined within 0.1 mm. The technique was applied to analyzing external random positioning errors from positional audit data for 112 pelvic radiotherapy patients. Patient position offsets were measured using portal imaging analysis and external body surface measures. Using MLE to analyze all methods in parallel it was possible to ascertain the measurement error for each method and the underlying positional <span class="hlt">variation</span>. In the (AP / Lat / SI) directions the standard deviations of the measured patient position errors from portal imaging were (3.3 mm / 2.3 mm / 1.9 mm), arising from underlying <span class="hlt">variations</span> of (2.7 mm / 1.5 mm / 1.4 mm) and measurement uncertainties of (1.8 mm / 1.8 mm / 1.3 mm), respectively. The measurement errors agree well with published studies. MLE used in this manner could be applied to any study in which the same quantity is measured using independent methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23020838','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23020838"><span>Temperature <span class="hlt">variation</span> of ultralow <span class="hlt">frequency</span> modes and mean square displacements in solid lasamide (diuretic drug) studied by 35Cl-NQR, X-ray and DFT/QTAIM.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Latosińska, Jolanta Natalia; Latosińska, Magdalena; Kasprzak, Jerzy; Tomczak, Magdalena; Maurin, Jan Krzysztof</p> <p>2012-10-25</p> <p>The application of combined (35)Cl-NQR/X-ray/DFT/QTAIM methods to study the temperature <span class="hlt">variation</span> of anisotropic displacement parameters and ultralow <span class="hlt">frequency</span> modes of anharmonic torsional vibrations in the solid state is illustrated on the example of 2,4-dichloro-5-sulfamolybenzoic acid (lasamide, DSBA) which is a diuretic and an intermediate in the synthesis of furosemide and thus its common impurity. The crystallographic structure of lasamide is solved by X-ray diffraction and refined to a final R-factor of 3.06% at room temperature. Lasamide is found to crystallize in the triclinic space group P-1, with two equivalent molecules in the unit cell a = 7.5984(3) Å, b = 8.3158(3) Å, c = 8.6892(3) Å; α = 81.212(3)°, β = 73.799(3)°, γ = 67.599(3)°. Its molecules form symmetric dimers linked by two short and linear intermolecular hydrogen bonds O-H···O (O-H···O = 2.648 Å and ∠OHO = 171.5°), which are further linked by weaker and longer intermolecular hydrogen bonds N-H···O (N-H···O = 2.965 Å and ∠NHO = 166.4°). Two (35)Cl-NQR resonance <span class="hlt">frequencies</span>, 36.899 and 37.129 MHz, revealed at room temperature are assigned to chlorine sites at the ortho and para positions, relative to the carboxyl functional group, respectively. The difference in C-Cl(1) and C-Cl(2) bond lengths only slightly affects the value of (35)Cl-NQR <span class="hlt">frequencies</span>, which results mainly from chemical inequivalence of chlorine atoms but also involvement in different intermolecular interactions pattern. The smooth decrease in both (35)Cl-NQR <span class="hlt">frequencies</span> with increasing temperature in the range of 77-300 K testifies to the averaging of EFG tensor at each chlorine site due to anharmonic torsional vibrations. Lasamide is thermally stable; no temperature-induced release of chlorine or decomposition of this compound is detected. The temperature dependence of ultralow <span class="hlt">frequency</span> modes of anharmonic small-angle internal torsional vibrations averaging EFG tensor and mean square angle</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E.979K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.979K"><span>The <span class="hlt">variations</span> of ionosphere critical <span class="hlt">frequency</span> of E layer over the equatorial geomagnetic region in Southeast Asia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kenpankho, Prasert; Ishii, Mamoru; Supnithi, Pornchai</p> <p>2016-07-01</p> <p>We investigate the values of the critical <span class="hlt">frequency</span> of the ionospheric E layer, foE, obtained at Chumphon ionospheric observatory station, Thailand. For a declining phase of the solar cycle 23 during the year 2005-2008 and an inclining phase of the solar cycle 24 during the year 2009-2013, the foE data have been used to investigate the foE <span class="hlt">variations</span> over the equatorial geomagnetic region in Southeast Asia. A comparison between the observation data and International Reference Ionosphere (IRI) 2012 model has also been investigated and studied. The results show that the foE obtained from IRI 2012 model underestimates foE from Chumphon station especially during the period of 7-11 am and after 6 pm for each day and all seasons. As the results combining with the previous investigations, we suggest that the underestimation of ionospheric foE by IRI 2012 model is helpful for the correction and improvement of IRI model in an equatorial Asia region.</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_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" 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_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</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="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22287162','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22287162"><span>Using <span class="hlt">frequency</span>-labeled exchange transfer to <span class="hlt">separate</span> out conventional magnetization transfer effects from exchange transfer effects when detecting ParaCEST agents.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lin, Chien-Yuan; Yadav, Nirbhay N; Friedman, Joshua I; Ratnakar, James; Sherry, A Dean; van Zijl, Peter C M</p> <p>2012-04-01</p> <p>Paramagnetic chemical exchange saturation transfer agents combine the benefits of a large chemical shift difference and a fast exchange rate for sensitive MRI detection. However, the in vivo detection of these agents is hampered by the need for high B(1) fields to allow sufficiently fast saturation before exchange occurs, thus causing interference of large magnetization transfer effects from semisolid macromolecules. A recently developed approach named <span class="hlt">frequency</span>-labeled exchange transfer utilizes excitation pulses instead of saturation pulses for detecting the exchanging protons. Using solutions and gel phantoms containing the europium (III) complex of DOTA tetraglycinate (EuDOTA-(gly)(-) (4) ), it is shown that <span class="hlt">frequency</span>-labeled exchange transfer allows the <span class="hlt">separation</span> of chemical exchange effects and magnetization transfer (MT) effects in the time domain, therefore allowing the study of the individual resonance of rapidly exchanging water molecules (k(ex) >10(4) s(-1) ) without interference from conventional broad-band MT.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70027606','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70027606"><span>Response of a hydrothermal system to magmatic heat inferred from temporal <span class="hlt">variations</span> in the complex <span class="hlt">frequencies</span> of long-period events at Kusatsu-Shirane Volcano, Japan</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nakano, M.; Kumagai, H.</p> <p>2005-01-01</p> <p>We investigate temporal <span class="hlt">variations</span> in the complex <span class="hlt">frequencies</span> (<span class="hlt">frequency</span> and quality factor Q) of long-period (LP) events that occurred at Kusatsu-Shirane Volcano, central Japan. We analyze LP waveforms observed at this volcano in the period between 1988 and 1995, which covers a seismically active period between 1989 and 1993. Systematic temporal <span class="hlt">variations</span> in the complex <span class="hlt">frequencies</span> are observed in October-November 1989, July-October 1991, and September 1992-January 1993. We use acoustic properties of a crack filled with hydrothermal fluids to interpret the observed temporal <span class="hlt">variations</span> in the complex <span class="hlt">frequencies</span>. The temporal <span class="hlt">variations</span> in October-November 1989 can be divided into two periods, which are explained by a gradual decrease and increase of a gas-volume fraction in a water-steam mixture in a crack, respectively. The temporal <span class="hlt">variations</span> in July-October 1991 can be also divided into two periods. These <span class="hlt">variations</span> in the first and second periods are similar to those observed in November 1989 and in September-November 1992, respectively, and are interpreted as drying of a water-steam mixture and misty gas in a crack, respectively. The repeated nature of the temporal <span class="hlt">variations</span> observed in similar seasons between July and November suggests the existence of seasonality in the occurrence of LP events. This may be caused by a seasonally variable meteoritic water supply to a hydrothermal system, which may have been heated by the flux of volcanic gases from magma beneath this volcano. ?? 2005 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70037005','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70037005"><span>Learning to be different: Acquired skills, social learning, <span class="hlt">frequency</span> dependence, and environmental <span class="hlt">variation</span> can cause behaviourally mediated foraging specializations</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Tinker, M.T.; Mangel, M.; Estes, J.A.</p> <p>2009-01-01</p> <p>) Offspring can learn foraging skills from their mothers (matrilineal social learning). (6) Food abundance is limited, such that average individual energy reserves are low Additionally, the following factors increase the likelihood of alternative specializations co-occurring in a predator population: (1) The predator exerts effective top-down control of prey abundance, resulting in <span class="hlt">frequency</span>-dependent dynamics. (2) There is stochastic <span class="hlt">Variation</span> in prey population dynamics, but this <span class="hlt">Variation</span> is neither too extreme in magnitude nor too 'slow' with respect to the time required for an individual forager to learn new foraging skills. For a given predator population, we deduce that the degree of specialization will be highest for those prey types requiring complex capture or handling skills, while prey species that are both profitable and easy to capture and handle will be included in the diet of all individuals. <span class="hlt">Frequency</span>-dependent benefits of selecting alternative prey types, combined with the ability of foragers to improve their foraging skills by learning, and transmit learned skills to offspring, can result in behaviourally mediated foraging specialization, and also lead to the co-existence of alternative specializations. The extent of such specialization is predicted to be a variable trait, increasing in locations or years when intra-specific competition is high relative to inter-specific competition. ?? 2009 M. Tim Tinker.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyB..456..108N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyB..456..108N"><span>Ferrimagnetism and magnetic phase <span class="hlt">separation</span> in Nd1-xYxMnO3 studied by magnetization and high <span class="hlt">frequency</span> electron paramagnetic resonance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nair, Harikrishnan S.; Yadav, Ruchika; Adiga, Shilpa; Rao, S. S.; van Tol, Johan; Elizabeth, Suja</p> <p>2015-01-01</p> <p>Ferrimagnetism and metamagnetic features tunable by composition are observed in the magnetic response of Nd1-xYxMnO3, for x=0.1-0.5. For all values of x in the series, the compound crystallizes in orthorhombic Pbnm space group similar to NdMnO3. Magnetization studies reveal a phase transition of the Mn-sublattice below <mml:msubsup> T N Mn ≈ 80 K for all compositions, which, decreases up on diluting the Nd-site with Yttrium. For x=0.35, ferrimagnetism is observed. At 5 K, metamagnetic transition is observed for all compositions x < 0.4. The evolution of magnetic ground states and appearance of ferrimagnetism in Nd1-xYxMnO3 can be accounted for by invoking the scenario of magnetic phase <span class="hlt">separation</span>. The high <span class="hlt">frequency</span> electron paramagnetic resonance measurements on x=0.4 sample, which is close to the critical composition for phase <span class="hlt">separation</span>, revealed complex temperature dependent lineshapes clearly supporting the assumption of magnetic phase <span class="hlt">separation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22305784','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22305784"><span><span class="hlt">Variations</span> of boundary reaction rate and particle size on the diffusion-induced stress in a phase <span class="hlt">separating</span> electrode</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhang, Lei; He, Linghui; Ni, Yong; Song, Yicheng</p> <p>2014-10-14</p> <p>In contrast to the case of single-phase delithiation wherein faster discharging leads to higher diffusion-induced stress (DIS), this paper reports nonmonotonous dependency of the boundary reaction rate on the DIS in nanosized spherical electrode accompanying phase <span class="hlt">separation</span>. It is attributed to a transition from two-phase to single-phase delithiation driven by increase of the boundary reaction rate leading to narrowing and vanishing of the miscibility gap in a range of the particle size. The profiles of lithium concentration and the DIS are identified during the transition based on a continuum model. The resultant maximum DIS first decreases in the region of two-phase delithiation and later returns to increase in the region of single-phase delithiation with the increase of the boundary reaction rate. A map for the failure behavior in the spherical electrode particle is constructed based on the Tresca failure criterion. These results indicate that the failure caused by the DIS can be avoided by appropriate selection of the said parameters in such electrodes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhRvA..95b3418K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhRvA..95b3418K"><span>Accuracy estimation of the O162+ transition <span class="hlt">frequencies</span> targeting the search for the <span class="hlt">variation</span> in the proton-electron mass ratio</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kajita, Masatoshi</p> <p>2017-02-01</p> <p>We estimate the Stark and Zeeman shifts in the transition <span class="hlt">frequencies</span> of the O162+ molecular ion as a step in the search for the <span class="hlt">variation</span> in the proton-to-electron mass ratio μ . The X2Π v =21 -a4Π v =0 or the X2Π v =21 -a4Π v =1 transition <span class="hlt">frequencies</span> (THz region) of the O162+ molecular ion have particularly high sensitivity to the <span class="hlt">variation</span> in μ . Note also that the Stark shift in the O162+ transition <span class="hlt">frequencies</span> is expected to be much smaller than that for heteronuclear diatomic molecules. However, the actual systematic uncertainties for the O162+ transition <span class="hlt">frequencies</span> have never been estimated. We estimated the Stark and Zeeman shifts in the different O162+ transition <span class="hlt">frequencies</span>. When the molecular ions in a string crystal formed in a linear trap (trap electric field <0.1 V/cm, and Stark shift <10-20 ) are used, the X2Π1 /2(v ,J ) =(0 ,1 /2 ) -(v',1 /2 ) (v'≥1 ) transition <span class="hlt">frequencies</span> are most advantageous for the search for the <span class="hlt">variation</span> in μ (" close=")v ,J )">Δ μ /μ <10-17</mml:mfenced> because the Zeeman shift is easily suppressed to lower than 10-18 and the electric quadrupole shift is zero. On the other hand, the X2Π1 /2(0 ,1 /2 ) transition <span class="hlt">frequency</span> has another merit in that the positive Stark shift induced by the trap electric field can be canceled by the quadratic Doppler shift. Therefore, the measurement using molecular ions in a Coulomb crystal broadened in the radial direction is also possible, when the Zeeman shift is effectively eliminated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21371011','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21371011"><span>EXPERIMENTAL-BASED DISCUSSION FOR THE <span class="hlt">SEPARATION</span> OF RESIDUAL STRESSES AND COLD WORK IN SHOT PEENED IN718 USING HIGH <span class="hlt">FREQUENCY</span> EDDY CURRENT SPECTROSCOPY</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hillmann, S.; Heuer, H.; Robbert, A.; Meyendorf, N.; Baron, H.-U.; Bamberg, J.</p> <p>2010-02-22</p> <p>Typical aero engine alloys, such as IN718, can be surface-treated by shot peening to induce near-surface compressive strains. To calculate the remaining operation time for those critical aero engine components, a quantitative nondestructive determination of near-surface strain gradients has to be developed. We have demonstrated in the past, that it is possible to obtain a characteristic depth profile (surface and sub-surface) of the electrical conductivity of shot peened specimen by using high-<span class="hlt">frequency</span> eddy current techniques. The measured conductivity profile is resulting from residual stresses, cold work, surface roughness, and the microstructure of the material. The objective is to measure residual stresses (<span class="hlt">separately</span> from other material properties) in such components after a defined life time. It can be assumed, that surface roughness and microstructure remain unchanged in IN718 materials over their lifetime, but cold work and residual stresses can change independently. Consequently, there is a need to clearly <span class="hlt">separate</span> the information from both material properties of received eddy current conductivity signals in order to obtain specific information related to residual stresses. This paper presents results acquired from different experiments, conducted to <span class="hlt">separate</span> both effects by using the eddy current technique on shot peened IN718 materials. We present different physical approaches and illustrate the experiments to solve them. In addition, we will demonstrate that there is a need to use additional techniques, for example ultrasonic time-of-flight measurements, to <span class="hlt">separate</span> the effects of residual stresses from compound (mixed) signals obtained on cold work samples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2364643','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2364643"><span>High <span class="hlt">Frequency</span> of Copy Number <span class="hlt">Variations</span> and Sequence Variants at CYP21A2 Locus: Implication for the Genetic Diagnosis of 21-Hydroxylase Deficiency</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Parajes, Silvia; Quinteiro, Celsa; Domínguez, Fernando; Loidi, Lourdes</p> <p>2008-01-01</p> <p>Background The systematic study of the human genome indicates that the inter-individual variability is greater than expected and it is not only related to sequence polymorphisms but also to gene copy number variants (CNVs). Congenital Adrenal Hyperplasia due to 21-hydroxylase deficiency (21OHD) is the most common autosomal recessive disorder with a carrier <span class="hlt">frequency</span> of 1∶25 to 1∶10. The gene that encodes 21-hydroxylase enzyme, CYP21A2, is considered to be one of the most polymorphic human genes. Copy number <span class="hlt">variations</span>, such as deletions, which are severe mutations common in 21OHD patients, or gene duplications, which have been reported as rare events, have also been described. The correct characterization of 21OHD alleles is important for disease carrier detection and genetic counselling Methodology and Findings CYP21A2 genotyping by sequencing has been performed in a random sample of the Spanish population, where 144 individuals recruited from university students and employees of the hospital were studied. The <span class="hlt">frequency</span> of CYP21A2 mutated alleles in our sample was 15.3% (77.3% were mild mutations, 9% were severe mutations and 13.6% were novel variants). Gene dosage assessment was also performed when CYP21A2 gene duplication was suspected. This analysis showed that 7% of individuals bore a chromosome with a duplicated CYP21A2 gene, where one of the copies was mutated. Conclusions As far as we know, the present study has shown the highest <span class="hlt">frequency</span> of 21OHD carriers reported by a genotyping analysis. In addition, a high <span class="hlt">frequency</span> of alleles with CYP21A2 duplications, which could be misinterpreted as 21OHD alleles, was found. Moreover, a high <span class="hlt">frequency</span> of novel genetic <span class="hlt">variations</span> with an unknown effect on 21-hydroxylase activity was also found. The high <span class="hlt">frequency</span> of gene duplications, as well as novel <span class="hlt">variations</span>, should be considered since they have an important involvement in carrier testing and genetic counseling. PMID:18478071</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JSV...392..170R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JSV...392..170R"><span>A new multi-<span class="hlt">frequency</span> approach based on Padé approximants for the treatment of transient dynamics problems with the <span class="hlt">variational</span> theory of complex rays</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rouzaud, C.; Gatuingt, F.; Hervé, G.; Dorival, O.</p> <p>2017-03-01</p> <p><span class="hlt">Frequency</span>-based methods were set up in order to circumvent the limits of classical finite element methods in fast dynamic simulations due to discretizations. In this approach the dynamic loading was shifted in the <span class="hlt">frequency</span> domain by FFT, then treated by the <span class="hlt">Variational</span> Theory of Complex Rays, and then the time response was reconstructed through an IFFT. This strategy proved to be very efficient due to the CPU VTCR very low cost. However in the case of a large loading spectrum this <span class="hlt">frequency-by-frequency</span> approach could seriously degrade the computational performances of the strategy. This paper addresses this point by proposing the use of Padé approximants in order to limit the number of <span class="hlt">frequencies</span> at which the response should be calculated. Padé approximation is applied to the overall VTCR system based on its <span class="hlt">frequency</span> dependency. Finally, as simulations on a simple academic case and on a civil engineering structure show, this method is found to be very efficient for interpolating the <span class="hlt">frequency</span> response functions of a complex structure. This is a key point to preserve the efficiency of the complete VTCR strategy for transient dynamic problems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20338711','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20338711"><span>Geographic <span class="hlt">variation</span> in the <span class="hlt">frequency</span> of isolation and fluconazole and voriconazole susceptibilities of Candida glabrata: an assessment from the ARTEMIS DISK Global Antifungal Surveillance Program.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pfaller, Michael A; Diekema, Daniel J; Gibbs, David L; Newell, Vance A; Barton, Richard; Bijie, Hu; Bille, Jacques; Chang, Shan-Chwen; da Luz Martins, Maria; Duse, Adriano; Dzierzanowska, Danuta; Ellis, David; Finquelievich, Jorge; Gould, Ian; Gur, Deniz; Hoosen, Anwar; Lee, Kyungwon; Mallatova, Nada; Mallie, Michele; Peng, N G Kee; Petrikos, George; Santiago, Axel; Trupl, Jan; VanDen Abeele, Ann Marie; Wadula, Jeannette; Zaidi, Mussaret</p> <p>2010-06-01</p> <p>Geographic differences in <span class="hlt">frequency</span> and azole resistance among Candida glabrata may impact empiric antifungal therapy choice. We examined geographic <span class="hlt">variation</span> in isolation and azole susceptibility of C. glabrata. We examined 23 305 clinical isolates of C. glabrata during ARTEMIS DISK global surveillance. Susceptibility testing to fluconazole and voriconazole was assessed by disk diffusion, and the results were grouped by geographic location: North America (NA) (2470 isolates), Latin America (LA) (2039), Europe (EU) (12 439), Africa and the Middle East (AME) (728), and Asia-Pacific (AP) (5629). Overall, C. glabrata accounted for 11.6% of 201 653 isolates of Candida and varied as a proportion of all Candida isolated from 7.4% in LA to 21.1% in NA. Decreased susceptibility (S) to fluconazole was observed in all geographic regions and ranged from 62.8% in AME to 76.7% in LA. <span class="hlt">Variation</span> in fluconazole susceptibility was observed within each region: AP (range, 50-100% S), AME (48-86.9%), EU (44.8-88%), LA (43-92%), and NA (74.5-91.6%). Voriconazole was more active than fluconazole (range, 82.3-84.2% S) with similar regional <span class="hlt">variation</span>. Among 22 sentinel sites participating in ARTEMIS from 2001 through 2007 (84 140 total isolates, 8163 C. glabrata), the <span class="hlt">frequency</span> of C. glabrata isolation increased in 14 sites and the <span class="hlt">frequency</span> of fluconazole resistance (R) increased in 11 sites over the 7-year period of study. The sites with the highest cumulative rates of fluconazole R were in Poland (22% R), the Czech Republic (27% R), Venezuela (27% R), and Greece (33% R). C. glabrata was most often isolated from blood, normally sterile body fluids and urine. There is substantial geographic and institutional <span class="hlt">variation</span> in both <span class="hlt">frequency</span> of isolation and azole resistance among C. glabrata. Prompt species identification and fluconazole susceptibility testing are necessary to optimize therapy for invasive candidiasis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25808847','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25808847"><span><span class="hlt">Separating</span> water-potential induced swelling and shrinking from measured radial stem <span class="hlt">variations</span> reveals a cambial growth and osmotic concentration signal.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chan, Tommy; Hölttä, Teemu; Berninger, Frank; Mäkinen, Harri; Nöjd, Pekka; Mencuccini, Maurizio; Nikinmaa, Eero</p> <p>2016-02-01</p> <p>The quantification of cambial growth over short time periods has been hampered by problems to discern between growth and the swelling and shrinking of a tree stem. This paper presents a model, which <span class="hlt">separates</span> cambial growth and reversible water-potential induced diurnal changes from simultaneously measured whole stem and xylem radial <span class="hlt">variations</span>, from field-measured Scots pine trees in Finland. The modelled growth, which includes osmotic concentration changes, was compared with (direct) dendrometer measurements and microcore samples. In addition, the relationship of modelled growth and dendrometer measurements to environmental factors was analysed. The results showed that the water-potential induced changes of tree radius were successfully <span class="hlt">separated</span> from stem growth. Daily growth predicted by the model exhibited a high correlation with the modelled daily changes of osmotic concentration in phloem, and a temperature dependency in early summer. Late-summer growth saw higher dependency on water availability and temperature. Evaluation of the model against dendrometer measurements showed that the latter masked a true environmental signal in stem growth due to water-potential induced changes. The model provides better understanding of radial growth physiology and offers potential to examine growth dynamics and changes due to osmotic concentration, and how the environment affects growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E.284C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.284C"><span>The pulse amplitude <span class="hlt">variation</span> with QPO <span class="hlt">frequency</span> in SAX J1808.4-3658: Resonances with the accretion disk</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caliskan, Sirin; Alpar, Mehmet Ali; Sasmaz Mus, Sinem</p> <p>2016-07-01</p> <p>SAX J1808.4-3658 is an accreting millisecond pulsar with a spin period of 401 Hz. The pulsed amplitudes of this source vary with its kHz QPO <span class="hlt">frequencies</span> (Bult & van der Klis 2015). The pulsed amplitude peaks at certain upper kHz QPO <span class="hlt">frequencies</span> which we associate with boundary layer modes of the viscous accretion disk (Erkut et al. 2008). We model this as peaks in the energy dissipation rate at the accretion caps due to resonances between the accretion column and the driving modes of the boundary layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/254432','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/254432"><span><span class="hlt">Frequency</span> <span class="hlt">variations</span> of quasi-periodic ELF-VLF emissions: A possible new ground-based diagnostic of the outer high-latitude magnetosphere</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Alford, J.; Engebretson, M.; Arnoldy, R.; Inan, U.</p> <p>1996-01-01</p> <p>Magnetic pulsations and quasi-periodic (QP) amplitude modulations of ELF-VLF waves at Pc 3-4 <span class="hlt">frequencies</span> (15-50 mHz) are commonly observed simultaneously in cusp-latitude data. The naturally occurring ELF-VLF emissions are believed to be modulated within the magnetosphere by the compressional component of geomagnetic pulsations formed external to the magnetosphere. The authors have examined data from South Pole Station (L {approximately} 14) to determine the occurrence and characteristics of QP emissions. On the basis of 14 months of data during 1987 and 1988 they found that QP emissions typically appeared in both the 0.5-1 kHz and 1-2 kHz receiver channels at South Pole Station and ocassionally in the 2-4 kHz channel. The QP emission <span class="hlt">frequency</span> appeared to depend on solar wind parameters and interplanetary magnetic field (IMF) direction, and the months near fall equinox in both 1987 and 1988 showed a significant increase in the percentage of QP emissions only in the lowest-<span class="hlt">frequency</span> channel. The authors present a model consistent with these <span class="hlt">variations</span> in which high-latitude (nonequatorial) magnetic field minima near the magnetopause play a major role, because the field magnitude governs both the <span class="hlt">frequency</span> of ELF-VLF emissions and the whistler mode propagation cutoffs. Because the field in these regions will be strongly influenced by solar wind and IMF parameters, <span class="hlt">variations</span> in the <span class="hlt">frequency</span> of such emissions may be useful in providing ground-based diagnostics of the outer high-latitude magnetosphere. 32 refs., 13 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17360212','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17360212"><span>Interannual <span class="hlt">variations</span> in feeding <span class="hlt">frequencies</span> and food quality of greater flamingo chicks (Phoenicopterus roseus): evidence from plasma chemistry and effects on body condition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Amat, Juan A; Hortas, Francisco; Arroyo, Gonzalo M; Rendón, Miguel A; Ramírez, José M; Rendón-Martos, Manuel; Pérez-Hurtado, Alejandro; Garrido, Araceli</p> <p>2007-06-01</p> <p>Greater flamingos in southern Spain foraged in areas distant from a breeding site, spending 4-6 days in foraging areas between successive visits to the colony to feed their chicks. During four years, we took blood samples from chicks to ascertain whether there were interannual <span class="hlt">variations</span> in several blood parameters, indicative of food quality and feeding <span class="hlt">frequencies</span>. When the chicks were captured, 20-31% of them had their crops empty, indicating that not all chicks were fed daily. Additional evidence of <span class="hlt">variations</span> in feeding <span class="hlt">frequencies</span> was obtained from a principal component analysis (PCA) on plasma chemistry values, which also indicated that there were annual <span class="hlt">variations</span> in the quality of food received by chicks. The association of cholesterol and glucose with some PC axes indicated that some chicks were experiencing fasting periods. Of all plasma metabolites considered, cholesterol was the best one to predict body condition. Greater flamingo chicks experiencing longer fasting intervals, as suggested by higher plasma levels of cholesterol, were in lower body condition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24558468','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24558468"><span>Modelling of human low <span class="hlt">frequency</span> sound localization acuity demonstrates dominance of spatial <span class="hlt">variation</span> of interaural time difference and suggests uniform just-noticeable differences in interaural time difference.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Smith, Rosanna C G; Price, Stephen R</p> <p>2014-01-01</p> <p>Sound source localization is critical to animal survival and for identification of auditory objects. We investigated the acuity with which humans localize low <span class="hlt">frequency</span>, pure tone sounds using timing differences between the ears. These small differences in time, known as interaural time differences or ITDs, are identified in a manner that allows localization acuity of around 1° at the midline. Acuity, a relative measure of localization ability, displays a non-linear <span class="hlt">variation</span> as sound sources are positioned more laterally. All species studied localize sounds best at the midline and progressively worse as the sound is located out towards the side. To understand why sound localization displays this <span class="hlt">variation</span> with azimuthal angle, we took a first-principles, systemic, analytical approach to model localization acuity. We calculated how ITDs vary with sound <span class="hlt">frequency</span>, head size and sound source location for humans. This allowed us to model ITD <span class="hlt">variation</span> for previously published experimental acuity data and determine the distribution of just-noticeable differences in ITD. Our results suggest that the best-fit model is one whereby just-noticeable differences in ITDs are identified with uniform or close to uniform sensitivity across the physiological range. We discuss how our results have several implications for neural ITD processing in different species as well as development of the auditory system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4985177','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4985177"><span>Highly-Efficient Charge <span class="hlt">Separation</span> and Polaron Delocalization in Polymer-Fullerene Bulk-Heterojunctions: A Comparative Multi-<span class="hlt">Frequency</span> EPR & DFT Study</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Niklas, Jens; Mardis, Kristy L.; Banks, Brian P.; Grooms, Gregory M.; Sperlich, Andreas; Dyakonov, Vladimir; Beaupré, Serge; Leclerc, Mario; Xu, Tao; Yu, Luping; Poluektov, Oleg G.</p> <p>2016-01-01</p> <p>The ongoing depletion of fossil fuels has led to an intensive search for additional renewable energy sources. Solar-based technologies could provide sufficient energy to satisfy the global economic demands in the near future. Photovoltaic (PV) cells are the most promising man-made devices for direct solar energy utilization. Understanding the charge <span class="hlt">separation</span> and charge transport in PV materials at a molecular level is crucial for improving the efficiency of the solar cells. Here, we use light-induced EPR spectroscopy combined with DFT calculations to study the electronic structure of charge <span class="hlt">separated</span> states in blends of polymers (P3HT, PCDTBT, and PTB7) and fullerene derivatives (C60-PCBM and C70-PCBM). Solar cells made with the same composites as active layers show power conversion efficiencies of 3.3% (P3HT), 6.1% (PCDTBT), and 7.3% (PTB7), respectively. Under illumination of these composites, two paramagnetic species are formed due to photo-induced electron transfer between the conjugated polymer and the fullerene. They are the positive, P+, and negative, P-, polarons on the polymer backbone and fullerene cage, respectively, and correspond to radical cations and radical anions. Using the high spectral resolution of high-<span class="hlt">frequency</span> EPR (130 GHz), the EPR spectra of these species were resolved and principal components of the g-tensors were assigned. Light-induced pulsed ENDOR spectroscopy allowed the determination of 1H hyperfine coupling constants of photogenerated positive and negative polarons. The experimental results obtained for the different polymer-fullerene composites have been compared with DFT calculations, revealing that in all three systems the positive polaron is distributed over distances of 40 - 60 Å on the polymer chain. This corresponds to about 15 thiophene units for P3HT, approximately three units PCDTBT, and about three to four units for PTB7. No spin density delocalization between neighboring fullerene molecules was detected by EPR. Strong</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23670645','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23670645"><span>Highly-efficient charge <span class="hlt">separation</span> and polaron delocalization in polymer-fullerene bulk-heterojunctions: a comparative multi-<span class="hlt">frequency</span> EPR and DFT study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Niklas, Jens; Mardis, Kristy L; Banks, Brian P; Grooms, Gregory M; Sperlich, Andreas; Dyakonov, Vladimir; Beaupré, Serge; Leclerc, Mario; Xu, Tao; Yu, Luping; Poluektov, Oleg G</p> <p>2013-06-28</p> <p>The ongoing depletion of fossil fuels has led to an intensive search for additional renewable energy sources. Solar-based technologies could provide sufficient energy to satisfy the global economic demands in the near future. Photovoltaic (PV) cells are the most promising man-made devices for direct solar energy utilization. Understanding the charge <span class="hlt">separation</span> and charge transport in PV materials at a molecular level is crucial for improving the efficiency of the solar cells. Here, we use light-induced EPR spectroscopy combined with DFT calculations to study the electronic structure of charge <span class="hlt">separated</span> states in blends of polymers (P3HT, PCDTBT, and PTB7) and fullerene derivatives (C60-PCBM and C70-PCBM). Solar cells made with the same composites as active layers show power conversion efficiencies of 3.3% (P3HT), 6.1% (PCDTBT), and 7.3% (PTB7), respectively. Upon illumination of these composites, two paramagnetic species are formed due to photo-induced electron transfer between the conjugated polymer and the fullerene. They are the positive, P(+), and negative, P(-), polarons on the polymer backbone and fullerene cage, respectively, and correspond to radical cations and radical anions. Using the high spectral resolution of high-<span class="hlt">frequency</span> EPR (130 GHz), the EPR spectra of these species were resolved and principal components of the g-tensors were assigned. Light-induced pulsed ENDOR spectroscopy allowed the determination of (1)H hyperfine coupling constants of photogenerated positive and negative polarons. The experimental results obtained for the different polymer-fullerene composites have been compared with DFT calculations, revealing that in all three systems the positive polaron is distributed over distances of 40-60 Å on the polymer chain. This corresponds to about 15 thiophene units for P3HT, approximately three units for PCDTBT, and about three to four units for PTB7. No spin density delocalization between neighboring fullerene molecules was detected by EPR</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=third+AND+language+AND+acquisition&pg=4&id=EJ1130009','ERIC'); return false;" href="http://eric.ed.gov/?q=third+AND+language+AND+acquisition&pg=4&id=EJ1130009"><span>A CDI Study of Bilingual English-Hebrew Children--<span class="hlt">Frequency</span> of Exposure as a Major Source of <span class="hlt">Variation</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>Armon-Lotem, Sharon; Ohana, Odelya</p> <p>2017-01-01</p> <p>The present study explores the vocabulary development of bilingual children when neither of their languages has a minority language status. With both languages having high relative prestige, it is possible to address the impact of exposure variables: age of onset, length of exposure, and <span class="hlt">frequency</span> of exposure (FoE) to both languages. Parents of 40…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/862448','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/862448"><span>Product <span class="hlt">separator</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Welsh, Robert A.; Deurbrouck, Albert W.</p> <p>1976-01-20</p> <p>A secondary light sensitive photoelectric product <span class="hlt">separator</span> for use with a primary product <span class="hlt">separator</span> that concentrates a material so that it is visually distinguishable from adjacent materials. The concentrate <span class="hlt">separation</span> is accomplished first by feeding the material onto a vibratory inclined surface with a liquid flow, such as a wet concentrating table. Vibrations generally perpendicular to the stream direction of flow cause the concentrate to <span class="hlt">separate</span> from its mixture according to its color. When the concentrate and its surrounding stream reach the recovery end of the table, a detecting device notes the line of color demarcation and triggers a signal if it differs from a normal condition. If no difference is noted nothing moves on the second <span class="hlt">separator</span>. However, if a difference is detected in the constant monitoring of the color line's location, a product splitter and recovery unit normally positioned near the color line at the recovery end, moves to a new position. In this manner the selected <span class="hlt">separated</span> concentrate is recovered at a maximum rate regardless of <span class="hlt">variations</span> in the flow stream or other conditions present.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4724046','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4724046"><span><span class="hlt">Variation</span> in style morph <span class="hlt">frequencies</span> in tristylous Lythrum salicaria in the Iberian Peninsula: the role of geographical and demographic factors</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Costa, Joana; Castro, Sílvia; Loureiro, João; Barrett, Spencer C. H.</p> <p>2016-01-01</p> <p>Background and Aims The balance between stochastic forces and negative <span class="hlt">frequency</span>-dependent selection largely determines style morph <span class="hlt">frequencies</span> in heterostylous populations. Investigation of morph <span class="hlt">frequencies</span> at geographical range limits can provide insights into the forces maintaining the floral polymorphism, and the factors causing biased morph ratios. Here, we investigate style morph <span class="hlt">frequencies</span> in populations at the south-western European range limit of tristylous Lythrum salicaria, to explore the role of demographic and geographical factors influencing morph ratios in its native range. Methods We measured morph composition and evenness, and the size of 96 populations, along a north to south latitudinal transect from Galicia to Andalucia, Iberian Peninsula, traversing a steep climatic gradient. To examine the potential influence of morph-specific fitness components on morph ratios, we examined reproductive traits in 19 populations. Key Results Most populations of L. salicaria were trimorphic (94·79 %), the majority exhibiting 1 : 1 : 1 morph ratios (68·75 %). Populations with biased morph ratios had a deficiency of the short-styled morph. Population size and morph evenness were positively associated with latitude, with smaller populations and those with less even morph ratios occurring towards the south. Greater variance in morph evenness was evident at the southern range margin. There were no consistent differences in components of reproductive fitness among style morphs, but southern populations produced less fruit and seed than more northerly populations. Conclusions Our results demonstrate the influence of finite population size on morph <span class="hlt">frequencies</span> in L. salicaria. However, they also illustrate the resilience of Iberian populations to the factors causing deviations from isoplethy and morph loss, especially at the southern range limit where populations are smaller. The maintenance of tristyly in small populations of L. salicaria may be aided</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_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" 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_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</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="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24020470','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24020470"><span>Body size <span class="hlt">variation</span> of four latitudinally-<span class="hlt">separated</span> populations of a toad species: age and growth rate as the proximate determinants.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yu, Tonglei; Lu, Xin</p> <p>2013-09-01</p> <p>Age and growth rate are critical parameters determining the body size of adult anurans, which grow indeterminately. Therefore, evaluating their relative importance and selective pressures acting on them may help to explain <span class="hlt">variation</span> in body size of anurans across geographical populations. Based on the data on body size and skeletochronological age of 4 Asiatic toad (Bufo gargarizans) populations that are widely <span class="hlt">separated</span> in latitude, the present study showed that toads at the northern extremity of the range were the oldest, on average, and grew relatively fast, toads at the southern end of the range were relatively old but grew fastest, whereas mid-latitude toads were intermediate in both traits. These results indicated that relative contributions of age and growth rate to body size differed among populations. From a life history perspective, greater age attained by toads at higher latitudes should result from delayed maturation, and faster growth from an adaptive response to strong seasonal time constraints; in contrast, selective pressures on the 2 parameters at lower latitudes might be associated, respectively, with low adult death rates and longer favorable growing seasons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Ge%26Ae..54..640P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Ge%26Ae..54..640P"><span>Annual <span class="hlt">variations</span> of the amplitude characteristic of the noise magnetic field in the ELF <span class="hlt">frequency</span> range based on the results of high-latitude observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pchelkin, V. V.</p> <p>2014-09-01</p> <p>The annual <span class="hlt">variation</span> of a number of amplitude characteristics of the noise electromagnetic field in the <span class="hlt">frequency</span> range near the first Schumann resonance (and in particular the mean values of the modulus of horizontal magnetic components and parameters of the distribution function of noise pulses over amplitudes) was obtained and analyzed based on the results of three-year measurements performed at the high-latitude magnetic observatory Lovozero. The summer increase in mean and median values of the magnetic component of noises associated with electrical storms and the lack of annual <span class="hlt">variations</span> of the exponent that empirically describes the distribution of amplitudes of noise signals were found. The relationship between the seasonal (winter/summer in the northern hemisphere) increase in the mean value of the modulus of the horizontal magnetic field component and seasonal increase in the global number of lightning discharges is shown by the correlation of the results of satellite observations and measurements of the magnetic component.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/2767673','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/2767673"><span><span class="hlt">Variation</span> in the gene <span class="hlt">frequencies</span> of three generations of humans from Monterrey, Nuevo León, Mexico.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cerda-Flores, R M; Garza-Chapa, R</p> <p>1989-04-01</p> <p>Allele <span class="hlt">frequencies</span> for the ABO, Rh, MNSs, Duffy, Kidd, Lutheran, P and Lewis blood group systems in 207 persons whose 4 grandparents were born in the Monterrey Metropolitan area (MMA), grouped into 3 generations, were ascertained along with other related population from the MMA, Mestizos from Saltillo, Coahuila and Tlaxcala, and from the populations thought to have contributed to their genetic constitution (native Mexican Indians and Spanish). Genetic admixture and distance estimates were calculated. Gene <span class="hlt">frequencies</span> of the three generations from MMA are intermediate to those of the ancestral populations, indicating that they are Mestizo but with a genetic structure different from Mestizos of Saltillo and Tlaxcala. Both genetic admixture and distance estimates indicate that the oldest generation exhibits the greatest Spanish influence which decreases in the youngest generation and in the other MMA populations as a result of the immigration from the central states of Mexico.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA565322','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA565322"><span>Improved High <span class="hlt">Frequency</span> Discrimination: A New Approach to Correct for Regional Source Scaling <span class="hlt">Variations</span> (POSTPRINT) Annual Report 2</span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>2012-03-20</p> <p>spectral ratios (e.g., Izutani and Kanamori , 2001). Figure 1 shows a typical S-wave source ratio result from Izutani (2005) for the 2004 Mw 6.7 Niigata...it has been proposed by Kanamori and Rivera (2004) that the scaling between moment and corner <span class="hlt">frequency</span> could take on the form, (2...and G. C. Beroza (2001). Does apparent stress vary with earthquake size?, Geophys. Res. Lett. 28: 3349–3352. Izutani Y. and Kanamori , H. (2001</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26738079','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26738079"><span>Dynamic response of cardiac autonomic nervous system activity to habitual exercise during gradual <span class="hlt">variation</span> of breathing <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>Nakamura, H</p> <p>2015-01-01</p> <p>The purpose of this study is to measure cardiac autonomic nervous system activity during breathing control with gradual alteration of the <span class="hlt">frequency</span> between habitual exercise and sedentary young male subjects. In this study, to evaluate CANS activity, Tone-Entropy analysis, which is based on statistical property of acceleration between consecutive R-R intervals, was used. Sixteen healthy young male subjects (21.6+/-1.4yrs) were participated in these experiments and their R-R interval sequences were recorded. The controlled breathing trials let the subjects synchronize their breathing <span class="hlt">frequency</span> ranging 3 to 30 breathing per minute. After that, breathing <span class="hlt">frequency</span> was gradually and reversely decreased from 30 to 3 breathing per minute. Before and after the breathing controlled trials, 5 minute voluntary breathing trials were performed. Our results showed that total CANS activities of HE group were activated more than those of SE group in the entire sections and also that, as compared with HE group, maximum of average HR in SE group was appeared at 30 breathing per minute and it is recognized that the statistically significant difference between HE and SE group was shown. In conclusion, our results suggest that efficiency of cardiac function on habitual exercise in breathing control may be quantitatively and graphically evaluated with HR and Tone-Entropy analysis without any physical stimulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/1372303','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/1372303"><span>HLA class II <span class="hlt">variation</span> in the Gila River Indian Community of Arizona: alleles, haplotypes, and a high <span class="hlt">frequency</span> epitope at the HLA-DR locus.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Williams, R C; McAuley, J E</p> <p>1992-01-01</p> <p>A genetic distribution for the HLA class II loci is described for 349 "full-blooded" Pima and Tohono O'odham Indians (Pimans) in the Gila River Indian Community. A high <span class="hlt">frequency</span> epitope in the *DRw52 family was defined by reactions with 31 alloantisera, which we have designated *DR3X6. It segregates as a codominant allele at HLA-DR with alleles *DR2, *DR4, and *DRw8, and has the highest <span class="hlt">frequency</span> yet reported for an HLA-DR specificity, 0.735. It forms a common haplotype with *DRw52 and *DQw3 that is a valuable marker for genetic admixture and anthropological studies. Phenotype and allele <span class="hlt">frequencies</span>, and haplotype <span class="hlt">frequencies</span> for two and three loci, are presented. <span class="hlt">Variation</span> at these loci is highly restricted, the mean heterozygosity for HLA-DR and HLA-DQ being 0.361. The Pimans represent a contemporary model for the Paleo-Indians who first entered North America 20,000 to 40,000 years ago.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRA..117.4321T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRA..117.4321T"><span><span class="hlt">Variation</span> of the first cut-off <span class="hlt">frequency</span> of the Earth-ionosphere waveguide observed by DEMETER</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Toledo-Redondo, S.; Parrot, M.; Salinas, A.</p> <p>2012-04-01</p> <p>More than four years of VLF electric field data recorded by DEMETER have been analyzed, in order to monitor the first cut-off <span class="hlt">frequency</span> (QTM1) of the Earth-ionosphere waveguide, at around 1.6-1.8 kHz. Since losses in a waveguide are maximized right at the cut-off <span class="hlt">frequency</span>, DEMETER (˜700 km orbit) can detect the minimum of energy of the leaking fields coming from the waveguide. This measurement permits to draw a global map of its value (f1), which is directly related to the effective height of the ionosphere (h) by the relation f1 = c/2h (c is the speed of light). It enables the remote sensing of the D region, which is one of the less known layers of the ionosphere, because it is too low for satellites to orbit inside it and too high for balloons to reach it. The effective height depends mainly on the electron density (Ne) and neutral density (Nn) profiles, which determine the plasma <span class="hlt">frequency</span> and the electron mobility. The effective height shifts downward 5-10 km in southern warm season in the South Pacific Ocean. Another effect is observed in the Indian and Atlantic Oceans; the effective height decreases its value twice a year, in the area of roughly ±15° from the geomagnetic equator. The main causes for the changes on the effective reflection height are the solar radiation and the thunderstorm activity. However, the observed shifts are more prominent over the oceans, and a possible explanation for this difference could be attributed to i) less polluted conditions above the oceans (aerosols change the atmospheric conductivity and then the global atmospheric electric circuit), ii) the effect of the current associated to the thunderclouds on the bottom of the ionosphere because thunderstorms are much more numerous above land, or iii) ionization by elves because their occurrence is larger above oceans.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.2056S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.2056S"><span>Low-<span class="hlt">frequency</span> Intensity <span class="hlt">Variation</span> of the South Asian High and its relationship to Boreal Summer Intraseasonal Oscillation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shang, Wei; Ren, Xuejuan</p> <p>2016-04-01</p> <p>The South Asian High (SAH) is an important member among the Asian summer monsoon circulations in the upper troposphere located over the Tibean Plateau and its surrounding areas during boreal summer. This research attempts to study the characteristics and mechanisms of low-<span class="hlt">frequency</span> oscillation of SAH, using daily ERA-Interim reanalysis dataset and NECP/NCAR OLR data. The empirical orthogonal function (EOF)analysis is performed on 200hPa geopotential height low-<span class="hlt">frequency</span> anomalies over the 20°-35°N, 35°-110°E for June, July and August from 1979 to 2013. The first EOF mode shows a monopole pattern capturing the strengthening or weakening of the SAH's body. The power spectrum analysis of the corresponding principal component (PC1) time series shows that the first mode has a period about 10-30 days. Positive anomalies appear in the 200hPa geopotential height and negative anomalies appear in their north side when SAH is in positive low-<span class="hlt">frequency</span> phase. A band with negative outgoing longwave radiation (OLR) anomalies presents from the Arabian Sea, north of Indian Peninsula to Southeast China and Japan Island. Correspondingly, positive anomalous rainfall are contiguous in the north of Indian Peninsula, south of Tibetan Plateau, Southeast China and Japan Island. The lead-lag regression analysis demonstrates that from day -12 to day 0, negative OLR anomalies band move northward and northwest from the equatorial Indian Ocean, the Bay of Bengals, the South China sea and Western North Pacific to the Arabian Sea, north of Indian Peninsula, south of Tibetan Plateau, Southeast China and Japan Island. Corresponding to OLR anomalies, positive rainfall anomalies band have the similar evolution. The spatial pattern of anomalies in integrated apparent heat source <Q1> and integrated apparent moisture sink <Q2> resemble that of rainfall and OLR, which correspond more anomalous condensation heat release. The lead-lag regression analysis also shows that the OLR band moving northward</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6037544','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6037544"><span>Seasonal, annual and geographic <span class="hlt">variation</span> in color morph <span class="hlt">frequencies</span> of the cricket frog, Acris crepitans, in Illinois</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gray, R.H.</p> <p>1983-01-01</p> <p>A three-year field study was conducted in Illinois to investigate seasonal, annual and geographic <span class="hlt">variation</span> in color morph proportions of the cricket frog, Acris crepitans. Life history information (i.e., time of overwintering, emergence of adults in spring, breeding, metamorphosis, emergence of juveniles in summer, and growth and survival) for A. crepitans color morphs was compared to evaluate the potential adaptive significance of this polymorphism. Although seasonal <span class="hlt">variations</span> in color morph proportions were not significant, some annual and geographic differences were. No differences were found among morphs related to the timing of various life history events. Studies of individual movements, dispersal, growth and survivorship also revealed no differences among morphs. Comparison of these data, as well as physiological and behavioral data for A. crepitans from Illinois, with similar data from Texas and elsewhere suggests that different factors must operate throughout the species range to maintain this color polymorphism. Chance may be a major factor in determining color morph proportions in localized populations in Illinois. 22 references, 5 figures, 3 tables.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23797104','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23797104"><span><span class="hlt">Variation</span> in meiotic recombination <span class="hlt">frequencies</span> between allelic transgenes inserted at different sites in the Drosophila melanogaster genome.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McMahan, Susan; Kohl, Kathryn P; Sekelsky, Jeff</p> <p>2013-08-07</p> <p>Meiotic crossovers are distributed nonrandomly across the genome. Classic studies in Drosophila suggest that the position of a gene along a chromosome arm can affect the outcome of the recombination process, with proximity to the centromere being associated with lower crossing over. To examine this phenomenon molecularly, we developed an assay that measures meiotic crossovers and noncrossover gene conversions between allelic transgenes inserted into different genomic positions. To facilitate collecting a large number of virgin females, we developed a useful genetic system that kills males and undesired classes of females. We found that the recombination <span class="hlt">frequency</span> at a site in the middle of the X chromosome, where crossovers are normally frequent, was similar to the <span class="hlt">frequency</span> at the centromere-proximal end of the euchromatin, where crossovers are normally infrequent. In contrast, we recovered no recombinants--crossovers or noncrossovers--at a site on chromosome 4 and at a site toward the distal end of the X chromosome. These results suggest that local sequence or chromatin features have a stronger impact on recombination rates in this transgene assay than position along the chromosome arm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.9899T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.9899T"><span>Assessing <span class="hlt">variation</span> in skeletal production from surface death assemblages on the basis of age-<span class="hlt">frequency</span> distributions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tomasovych, Adam; Kidwell, Susan M.; Foygel Barber, Rina</p> <p>2015-04-01</p> <p>Age-<span class="hlt">frequency</span> distributions of dead skeletal material that capture information on the elapsed time since death of individuals on the landscape or seabed provide decadal- to millennial-scale windows into the history of production and on the processes that lead to skeletal disintegration and burial. However, models quantifying the dynamics of skeletal loss assumed that skeletal production has been constant during accumulation of death assemblages. Here, we assess the joint effects of temporally-variable production and skeletal loss on the shape of postmortem age-<span class="hlt">frequency</span> distributions. We show that the modes of such distributions will tend to be shifted to younger age cohorts relative to the true timing of past production pulses. This shift in the timing of a past production will be higher where loss rates are high and/or the rate of decline in production is slow. We apply the models combining the dynamic of loss and production to death assemblages with the deposit-feeding bivalve Nuculana taphria from the Southern California continental shelf, finding that (1) an onshore-offshore gradient in time averaging is dominated by a gradient in the timing of production, corresponding to the tracking of shallow-water habitats under a sea-level rise, and (2) model estimates of the timing of past production are in good agreement with an independent sea-level curve.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4226647','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4226647"><span>Microsatellite <span class="hlt">frequencies</span> vary with body mass and body temperature in mammals, suggesting correlated <span class="hlt">variation</span> in mutation rate</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Filipe, Laura N.S.</p> <p>2014-01-01</p> <p>Substitution rate is often found to correlate with life history traits such as body mass, a predictor of population size and longevity, and body temperature. The underlying mechanism is unclear but most models invoke either natural selection or factors such as generation length that change the number of mutation opportunities per unit time. Here we use published genome sequences from 69 mammals to ask whether life history traits impact another form of genetic mutation, the high rates of predominantly neutral slippage in microsatellites. We find that the length-<span class="hlt">frequency</span> distributions of three common dinucleotide motifs differ greatly between even closely related species. These <span class="hlt">frequency</span> differences correlate with body mass and body temperature and can be used to predict the phenotype of an unknown species. Importantly, different length microsatellites show complicated patterns of excess and deficit that cannot be explained by a simple model where species with short generation lengths have experienced more mutations. Instead, the patterns probably require changes in mutation rate that impact alleles of different length to different extents. Body temperature plausibly influences mutation rate by modulating the propensity for slippage. Existing hypotheses struggle to account for a link between body mass and mutation rate. However, body mass correlates inversely with population size, which in turn predicts heterozygosity. We suggest that heterozygote instability, HI, the idea that heterozygous sites show increased mutability, could provide a plausible link between body mass and mutation rate. PMID:25392761</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.S33A2395A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.S33A2395A"><span>Investigation of global <span class="hlt">variations</span> in the in amplitude and <span class="hlt">frequency</span> content of the PdP, SdS and Pds phases from common upper mantle discontinuities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ainiwaer, A.; Gurrola, H.; Zou, Z.</p> <p>2013-12-01</p> <p>The global existence of transition zone discontinuities at 410 km and 660 km depths and both almost universally observed in PdP, SdS and Pds data but the 520 and 660 are usually not observed in PdP data.. Discontinuities at approximately 220 km and 520 km depth are observed in these types of data at many regions. The discontinuities at 410, 520 and 660 km are believed to be the polymorphic phase transition zone in olivine. At 410 km discontinuity, α-olivine transforms to β-wadsleyite while γ-ringwoodite decomposes into wusite and provskite at 660 discontinuity while the 220 is usually considered to be the LAB and caused by partial melt. The contrast of elastic properties and the thickness of discontinuity can be estimated by investigating the amplitude of reflected or converted seismic waves. Recent progress in our ability to image these discontinuities in PP and SS data have made it possible to image these PdP and SdS phases to a much as 4 Hz. This will make it possible to investigate the <span class="hlt">frequency</span> response of these phases to <span class="hlt">frequencies</span> previously not possible; analysis of which makes it possible add new insight as to the nature of these boundaries. For example beneath the regions beneath the Line Island and the Aleutian Trench The PdP phase has amplitudes of 0.04 to 0.08, which is significantly higher than beneath Hawaii(0.02-0.04) and the region near the Nazca Plate and South American subduction zone Plate where the PdP phase has amplitudes of 0.02-0.04. We interpret that the difference of reflection amplitudes is the result of <span class="hlt">variations</span> in the impedance between layers due to <span class="hlt">variations</span> in the velocity and density contrast and the sharpness thereof. For example in most region investigated the P510P is not present in our data but is present in some regions such as the Line Islands. But the phase change expected for the 520 is usually considered to occur over a wide range of depths in which case it should not be visible anywhere at such high <span class="hlt">frequencies</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150017753','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150017753"><span>Seasonal <span class="hlt">Variations</span> of the James Webb Space Telescope Orbital Dynamics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brown, Jonathan; Peterson, Jeremy; Villac, Benjamin; Yu, Wayne</p> <p>2015-01-01</p> <p>LV <span class="hlt">separation</span> state is fixed ECEF, so inertial states vary with hourly, daily, monthly, and yearly <span class="hlt">frequencies</span> The net effect of all <span class="hlt">frequencies</span> leads to significant <span class="hlt">variations</span> in orbit geometry Injection states can be matched with invariant manifolds of periodic orbits in the CR3BP to explain observed final orbit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5056762','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5056762"><span>Estimating KIR Haplotype <span class="hlt">Frequencies</span> on a Cohort of 10,000 Individuals: A Comprehensive Study on Population <span class="hlt">Variations</span>, Typing Resolutions, and Reference Haplotypes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jayaraman, Jyothi; Trowsdale, John; Traherne, James; Kuang, Rui; Spellman, Stephen; Maiers, Martin</p> <p>2016-01-01</p> <p>The killer cell immunoglobulin-like receptors (KIR) mediate human natural killer (NK) cell cytotoxicity via activating or inhibiting signals. Although informative and functional haplotype patterns have been reported, most genotyping has been performed at resolutions that are structurally ambiguous. In order to leverage structural information given low-resolution genotypes, we performed experiments to quantify the effects of population <span class="hlt">variations</span>, reference haplotypes, and genotyping resolutions on population-level haplotype <span class="hlt">frequency</span> estimations as well as predictions of individual haplotypes. We genotyped 10,157 unrelated individuals in 5 populations (518 African American[AFA], 258 Asian or Pacific Islander[API], 8,245 European[EUR], 1,073 Hispanic[HIS], and 63 Native American[NAM]) for KIR gene presence/absence (PA), and additionally half of the AFA samples for KIR gene copy number <span class="hlt">variation</span> (CNV). A custom EM algorithm was used to estimate haplotype <span class="hlt">frequencies</span> for each population by interpretation in the context of three sets of reference haplotypes. The algorithm also assigns each individual the haplotype pairs of maximum likelihood. Generally, our haplotype <span class="hlt">frequency</span> estimates agree with similar previous publications to within <5% difference for all haplotypes. The exception is that estimates for NAM from the U.S. showed higher <span class="hlt">frequency</span> association of cB02 with tA01 (+14%) instead of tB01 (-8.5%) compared to a previous study of NAM from south of the U.S. The higher-resolution CNV genotyping on the AFA samples allowed unambiguous haplotype-pair assignments for the majority of individuals, resulting in a 22% higher median typing resolution score (TRS), which measures likelihood of self-match in the context of population-specific haplo- and geno-types. The use of TRS to quantify reduced ambiguity with CNV data clearly revealed the few individuals with ambiguous genotypes as outliers. It is observed that typing resolution and reference haplotype set influence</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGeod..85..565A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGeod..85..565A"><span>Assessment of periodic sub-diurnal Earth rotation <span class="hlt">variations</span> at tidal <span class="hlt">frequencies</span> through transformation of VLBI normal equation systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Artz, Thomas; Tesmer Née Böckmann, Sarah; Nothnagel, Axel</p> <p>2011-09-01</p> <p>We present an empirical model for periodic <span class="hlt">variations</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25392473','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25392473"><span>Higher <span class="hlt">frequency</span> of social learning in China than in the West shows cultural <span class="hlt">variation</span> in the dynamics of cultural evolution.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mesoudi, Alex; Chang, Lei; Murray, Keelin; Lu, Hui Jing</p> <p>2015-01-07</p> <p>Cultural evolutionary models have identified a range of conditions under which social learning (copying others) is predicted to be adaptive relative to asocial learning (learning on one's own), particularly in humans where socially learned information can accumulate over successive generations. However, cultural evolution and behavioural economics experiments have consistently shown apparently maladaptive under-utilization of social information in Western populations. Here we provide experimental evidence of cultural <span class="hlt">variation</span> in people's use of social learning, potentially explaining this mismatch. People in mainland China showed significantly more social learning than British people in an artefact-design task designed to assess the adaptiveness of social information use. People in Hong Kong, and Chinese immigrants in the UK, resembled British people in their social information use, suggesting a recent shift in these groups from social to asocial learning due to exposure to Western culture. Finally, Chinese mainland participants responded less than other participants to increased environmental change within the task. Our results suggest that learning strategies in humans are culturally variable and not genetically fixed, necessitating the study of the 'social learning of social learning strategies' whereby the dynamics of cultural evolution are responsive to social processes, such as migration, education and globalization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4262178','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4262178"><span>Higher <span class="hlt">frequency</span> of social learning in China than in the West shows cultural <span class="hlt">variation</span> in the dynamics of cultural evolution</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mesoudi, Alex; Chang, Lei; Murray, Keelin; Lu, Hui Jing</p> <p>2015-01-01</p> <p>Cultural evolutionary models have identified a range of conditions under which social learning (copying others) is predicted to be adaptive relative to asocial learning (learning on one's own), particularly in humans where socially learned information can accumulate over successive generations. However, cultural evolution and behavioural economics experiments have consistently shown apparently maladaptive under-utilization of social information in Western populations. Here we provide experimental evidence of cultural <span class="hlt">variation</span> in people's use of social learning, potentially explaining this mismatch. People in mainland China showed significantly more social learning than British people in an artefact-design task designed to assess the adaptiveness of social information use. People in Hong Kong, and Chinese immigrants in the UK, resembled British people in their social information use, suggesting a recent shift in these groups from social to asocial learning due to exposure to Western culture. Finally, Chinese mainland participants responded less than other participants to increased environmental change within the task. Our results suggest that learning strategies in humans are culturally variable and not genetically fixed, necessitating the study of the ‘social learning of social learning strategies' whereby the dynamics of cultural evolution are responsive to social processes, such as migration, education and globalization. PMID:25392473</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CSR...117...92L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CSR...117...92L"><span>High <span class="hlt">frequency</span> (hourly) <span class="hlt">variation</span> in vertical distribution and abundance of meroplanktonic larvae in nearshore waters during strong internal tidal forcing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liévana MacTavish, A.; Ladah, L. B.; Lavín, M. F.; Filonov, A.; Tapia, Fabian J.; Leichter, J.</p> <p>2016-04-01</p> <p>We related the vertical distribution and abundance of nearshore meroplankton at hourly time scales with internal tidal wave events. We proposed that significant changes in plankter abundance would occur across internal tidal fronts, and that surface and bottom strata would respond in opposite fashions. First-mode internal tidal bores propagating in the alongshore direction were detected in water-column currents and baroclinic temperature changes. Surface and bottom currents always flowed in opposite directions, and abrupt flow reversals coincided with large temperature changes during arrival of bores. Crab zoeae and barnacle cyprids were more abundant in the bottom strata, whereas barnacle nauplii showed the opposite pattern. Significant changes in vertical distribution and abundance of target meroplankters occurred across internal tidal fronts, especially for crabs at depth, with surface and bottom organisms responding in opposite fashions. Changes in plankter abundance were significantly correlated with current flows in the strata where they were most abundant. The manner in which plankters were affected (increasing or decreasing abundance) appeared to be modulated by their vertical position within the water column. The significant differences found at the high <span class="hlt">frequencies</span> of this study, maintained across sampling days, suggest that nearshore meroplankton populations may have greater and more consistent temporal and vertical variability than previously considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70020283','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70020283"><span>Spatial <span class="hlt">variations</span> in the <span class="hlt">frequency</span>-magnitude distribution of earthquakes at Soufriere Hills Volcano, Montserrat, West Indies</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Power, J.A.; Wyss, M.; Latchman, J.L.</p> <p>1998-01-01</p> <p>The <span class="hlt">frequency</span>-magnitude distribution of earthquakes measured by the b-value is determined as a function of space beneath Soufriere Hills Volcano, Montserrat, from data recorded between August 1, 1995 and March 31, 1996. A volume of anomalously high b-values (b > 3.0) with a 1.5 km radius is imaged at depths of 0 and 1.5 km beneath English's Crater and Chance's Peak. This high b-value anomaly extends southwest to Gage's Soufriere. At depths greater than 2.5 km volumes of comparatively low b-values (b-1) are found beneath St. George's Hill, Windy Hill, and below 2.5 km depth and to the south of English's Crater. We speculate the depth of high b-value anomalies under volcanoes may be a function of silica content, modified by some additional factors, with the most siliceous having these volumes that are highly fractured or contain high pore pressure at the shallowest depths. Copyright 1998 by the American Geophysical Union.</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_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" 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_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</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="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.V11C0746O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.V11C0746O"><span>Nature of low <span class="hlt">frequency</span> earthquakes observed at Asama volcano, Japan: Time <span class="hlt">variation</span> of wave parameters and hypocenter distribution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oikawa, J.; Ida, Y.</p> <p>2007-12-01</p> <p>Long period (LP) events called N-type earthquakes are typical phenomena observed at many active volcanoes, such as Kusatsu-Shirane, Asama, Tokachi-dake volcanoes. They are probably related to activities of magma, ground water or volcanic gas and many source mechanisms such as resonance of fluid cracks or spheres are proposed. In this study, we analyze the LP events observed at Asama volcano in Dec. 1-10, 1996, to reveal their source process with the high quality data obtained by the seismic network close to the summit crater of the volcano. We observed 112 N-type earthquakes during the period. The waveforms of these events seem to be a quasi-monochromatic oscillation with gradually decreasing amplitude. The spectrum has a dominant peak at 1.6-7.2 Hz, most of which make a group (Group 0) in which the dominant peak changes from 2.0 Hz to 1.6 Hz gradually, indicating that the scale or the physical properties of the LP source changes gradually if we accept the resonance model. Other groups appear in Dec. 3-6 (Group 1) and in Dec. 9-10 (Group 2) in which the dominant peak changes from 7.2 Hz to 1.4 Hz and 4.3 Hz to 1.6 Hz gradually, respectively. This indicates that two or more sources of the N-type earthquakes exist simultaneously. Attenuation factors have a positive but weak correlation with the <span class="hlt">frequency</span> of dominant peaks. Hypocenters of the events determined by the travel time of the first motion are concentrated within a depth of 300 m underneath the summit crater and are distributed in the shallow part of the region where B-type earthquakes occur. The events of Group 0 are concentrated underneath the southwest side of the crater, and the events of Group 1 and 2 distribute in the east side of the crater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3469346','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3469346"><span>Celiac disease T-cell epitopes from gamma-gliadins: immunoreactivity depends on the genome of origin, transcript <span class="hlt">frequency</span>, and flanking protein <span class="hlt">variation</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></p> <p>2012-01-01</p> <p>Background Celiac disease (CD) is caused by an uncontrolled immune response to gluten, a heterogeneous mixture of wheat storage proteins. The CD-toxicity of these proteins and their derived peptides is depending on the presence of specific T-cell epitopes (9-mer peptides; CD epitopes) that mediate the stimulation of HLA-DQ2/8 restricted T-cells. Next to the thoroughly characterized major T-cell epitopes derived from the α-gliadin fraction of gluten, γ-gliadin peptides are also known to stimulate T-cells of celiac disease patients. To pinpoint CD-toxic γ-gliadins in hexaploid bread wheat, we examined the <span class="hlt">variation</span> of T-cell epitopes involved in CD in γ-gliadin transcripts of developing bread wheat grains. Results A detailed analysis of the genetic <span class="hlt">variation</span> present in γ-gliadin transcripts of bread wheat (T. aestivum, allo-hexaploid, carrying the A, B and D genome), together with genomic γ-gliadin sequences from ancestrally related diploid wheat species, enabled the assignment of sequence variants to one of the three genomic γ-gliadin loci, Gli-A1, Gli-B1 or Gli-D1. Almost half of the γ-gliadin transcripts of bread wheat (49%) was assigned to locus Gli-D1. Transcripts from each locus differed in CD epitope content and composition. The Gli-D1 transcripts contained the highest <span class="hlt">frequency</span> of canonical CD epitope cores (on average 10.1 per transcript) followed by the Gli-A1 transcripts (8.6) and the Gli-B1 transcripts (5.4). The natural variants of the major CD epitope from γ-gliadins, DQ2-γ-I, showed <span class="hlt">variation</span> in their capacity to induce in vitro proliferation of a DQ2-γ-I specific and HLA-DQ2 restricted T-cell clone. Conclusions Evaluating the CD epitopes derived from γ-gliadins in their natural context of flanking protein <span class="hlt">variation</span>, genome specificity and transcript <span class="hlt">frequency</span> is a significant step towards accurate quantification of the CD toxicity of bread wheat. This approach can be used to predict relative levels of CD toxicity of individual wheat</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4959233','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4959233"><span>Mycoplasma agalactiae Secretion of β-(1→6)-Glucan, a Rare Polysaccharide in Prokaryotes, Is Governed by High-<span class="hlt">Frequency</span> Phase <span class="hlt">Variation</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>Baranowski, E.; Pau-Roblot, C.; Sagné, E.; Citti, C.</p> <p>2016-01-01</p> <p>ABSTRACT Mycoplasmas are minimal, wall-less bacteria but have retained the ability to secrete complex carbohydrate polymers that constitute a glycocalyx. In members of the Mycoplasma mycoides cluster, which are important ruminant pathogens, the glycocalyx includes both cell-attached and cell-free polysaccharides. This report explores the potential secretion of polysaccharides by M. agalactiae, another ruminant pathogen that belongs to a distant phylogenetic group. Comparative genomic analyses showed that M. agalactiae possesses all the genes required for polysaccharide secretion. Notably, a putative synthase gene (gsmA) was identified, by in silico reconstruction of the biosynthetic pathway, that could be involved in both polymerization and export of the carbohydrate polymers. M. agalactiae polysaccharides were then purified in vitro and found to be mainly cell attached, with a linear β-(1→6)-glucopyranose structure [β-(1→6)-glucan]. Secretion of β-(1→6)-glucan was further shown to rely on the presence of a functional gsmA gene, whose expression is subjected to high-<span class="hlt">frequency</span> phase <span class="hlt">variation</span>. This event is governed by the spontaneous intraclonal <span class="hlt">variation</span> in length of a poly(G) tract located in the gsmA coding sequence and was shown to occur in most of the M. agalactiae clinical isolates tested in this study. M. agalactiae susceptibility to serum-killing activity appeared to be dictated by ON/OFF switching of β-(1→6)-glucan secretion, suggesting a role of this phenomenon in survival of the pathogen when it invades the host bloodstream. Finally, β-(1→6)-glucan secretion was not restricted to M. agalactiae but was detected also in M. mycoides subsp. capri PG3T, another pathogen of small ruminants. IMPORTANCE Many if not all bacteria are able to secrete polysaccharides, either attached to the cell surface or exported unbound into the extracellular environment. Both types of polysaccharides can play a role in bacterium-host interactions. Mycoplasmas are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26978944','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26978944"><span>High-<span class="hlt">Frequency</span> Observation of Water Spectrum and Its Application in Monitoring of Dynamic <span class="hlt">Variation</span> of Suspended Materials in the Hangzhou Bay.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dai, Qian; Pan, De-lu; He, Xian-qiang; Zhu, Qian-kun; Gong, Fang; Huang, Hai-qing</p> <p>2015-11-01</p> <p>In situ measurement of water spectrum is the basis of the validation of the ocean color remote sensing. The traditional method to obtain the water spectrum is based on the shipboard measurement at limited stations, which is difficult to meet the requirement of validation of ocean color remote sensing in the highly dynamic coastal waters. To overcome this shortage, continuously observing systems of water spectrum have been developed in the world. However, so far, there are still few high-<span class="hlt">frequency</span> observation systems of the water spectrum in coastal waters, especially in the highly turbid and high-dynamic waters. Here, we established a high-<span class="hlt">frequency</span> water-spectrum observing system based on tower in the Hangzhou Bay. The system measures the water spectrum at a step of 3 minutes, which can fully match the satellite observation. In this paper, we primarily developed a data processing method for the tower-based high-<span class="hlt">frequency</span> water spectrum data, to realize automatic judgment of clear sky, sun glint, platform shadow, and weak illumination, etc. , and verified the processing results. The results show that the normalized water-leaving radiance spectra obtained through tower observation have relatively high consistency with the shipboard measurement results, with correlation coefficient of more than 0. 99, and average relative error of 9.96%. In addition, the long-term observation capability of the tower-based high-<span class="hlt">frequency</span> water-spectrum observing system was evaluated, and the results show that although the system has run for one year, the normalized water-leaving radiance obtained by this system have good consistency with the synchronously measurement by Portable spectrometer ASD in respect of spectral shape and value, with correlation coefficient of more than 0.90 and average relative error of 6.48%. Moreover, the water spectra from high-<span class="hlt">frequency</span> observation by the system can be used to effectively monitor the rapid dynamic <span class="hlt">variation</span> in concentration of suspended</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PMB....62.1149W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PMB....62.1149W"><span>An analysis of intrinsic <span class="hlt">variations</span> of low-<span class="hlt">frequency</span> shear wave speed in a stochastic tissue model: the first application for staging liver fibrosis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Yu; Wang, Min; Jiang, Jingfeng</p> <p>2017-02-01</p> <p>Shear wave elastography is increasingly being used to non-invasively stage liver fibrosis by measuring shear wave speed (SWS). This study quantitatively investigates intrinsic <span class="hlt">variations</span> among SWS measurements obtained from heterogeneous media such as fibrotic livers. More specifically, it aims to demonstrate that intrinsic <span class="hlt">variations</span> in SWS measurements, in general, follow a non-Gaussian distribution and are related to the heterogeneous nature of the medium being measured. Using the principle of maximum entropy (ME), our primary objective is to derive a probability density function (PDF) of the SWS distribution in conjunction with a lossless stochastic tissue model. Our secondary objective is to evaluate the performance of the proposed PDF using Monte Carlo (MC)-simulated shear wave (SW) data against three other commonly used PDFs. Based on statistical evaluation criteria, initial results showed that the derived PDF fits better to MC-simulated SWS data than the other three PDFs. It was also found that SW fronts stabilized after a short (compared with the SW wavelength) travel distance in lossless media. Furthermore, in lossless media, the distance required to stabilize the SW propagation was not correlated to the SW wavelength at the low <span class="hlt">frequencies</span> investigated (i.e. 50, 100 and 150 Hz). Examination of the MC simulation data suggests that elastic (shear) wave scattering became more pronounced when the volume fraction of hard inclusions increased from 10 to 30%. In conclusion, using the principle of ME, we theoretically demonstrated for the first time that SWS measurements in this model follow a non-Gaussian distribution. Preliminary data indicated that the proposed PDF can quantitatively represent intrinsic <span class="hlt">variations</span> in SWS measurements simulated using a two-phase random medium model. The advantages of the proposed PDF are its physically meaningful parameters and solid theoretical basis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AdSpR..58..326G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AdSpR..58..326G"><span>Modeling the <span class="hlt">variations</span> of reflection coefficient of Earth's lower ionosphere using very low <span class="hlt">frequency</span> radio wave data by artificial neural network</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ghanbari, Keyvan; Khakian Ghomi, Mehdi; Mohammadi, Mohammad; Marbouti, Marjan; Tan, Le Minh</p> <p>2016-08-01</p> <p>The ionized atmosphere lying from 50 to 600 km above surface, known as ionosphere, contains high amount of electrons and ions. Very Low <span class="hlt">Frequency</span> (VLF) radio waves with <span class="hlt">frequencies</span> between 3 and 30 kHz are reflected from the lower ionosphere specifically D-region. A lot of applications in long range communications and navigation systems have been inspired by this characteristic of ionosphere. There are several factors which affect the ionization rate in this region, such as: time of day (presence of sun in the sky), solar zenith angle (seasons) and solar activities. Due to nonlinear response of ionospheric reflection coefficient to these factors, finding an accurate relation between these parameters and reflection coefficient is an arduous task. In order to model these kinds of nonlinear functionalities, some numerical methods are employed. One of these methods is artificial neural network (ANN). In this paper, the VLF radio wave data of 4 sudden ionospheric disturbance (SID) stations are given to a multi-layer perceptron ANN in order to simulate the <span class="hlt">variations</span> of reflection coefficient of D region ionosphere. After training, validation and testing the ANN, outputs of ANN and observed values are plotted together for 2 random cases of each station. By evaluating the results using 2 parameters of pearson correlation coefficient and root mean square error, a satisfying agreement was found between ANN outputs and real observed data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5184738','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5184738"><span><span class="hlt">Frequency</span> dependence of pulsar integrated profiles</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Thorsett, S.E. )</p> <p>1991-08-01</p> <p>The dependence of component <span class="hlt">separation</span> on observing <span class="hlt">frequency</span> has been studied for seven pulsars that exhibit double- or multiple-component average profiles. In each case, a review of all available data shows a smooth <span class="hlt">variation</span> of given form. No evidence is found for a 'break <span class="hlt">frequency</span>' at which the <span class="hlt">separation</span> behavior discretely changes. It is argued that previous reports of such a discontinuity are due to insufficiently sampled data together with a prejudice toward pure power-law functional behaviors. The absence of such a break has implications for theories of the pulsar emission mechanism and of the propagation of radio waves in the pulsar magnetosphere. 44 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000056935','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000056935"><span>Hg(+) <span class="hlt">Frequency</span> Standards</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prestage, John D.; Tjoelker, Robert L.; Maleki, Lute</p> <p>2000-01-01</p> <p>In this paper we review the development of Hg(+) microwave <span class="hlt">frequency</span> standards for use in high reliability and continuous operation applications. In recent work we have demonstrated short-term <span class="hlt">frequency</span> stability of 3 x 10(exp -14)/nu(sub tau) when a cryogenic oscillator of stability 2-3 x 10(exp 15) was used a the local oscillator. The trapped ion <span class="hlt">frequency</span> standard employs a Hg-202 discharge lamp to optically pump the trapped Hg(+)-199 clock ions and a helium buffer gas to cool the ions to near room temperature. We describe a small Hg(+) ion trap based <span class="hlt">frequency</span> standard with an extended linear ion trap (LITE) architecture which <span class="hlt">separates</span> the optical state selection region from the clock resonance region. This <span class="hlt">separation</span> allows the use of novel trap configurations in the resonance region since no optical pumping is carried out there. A method for measuring the size of an ion cloud inside a linear trap with a 12-rod trap is currently being investigated. At approx. 10(exp -12), the 2nd order Doppler shift for trapped mercury ion <span class="hlt">frequency</span> standards is one of the largest <span class="hlt">frequency</span> offsets and its measurement to the 1% level would represent an advance in insuring the very long-term stability of these standards to the 10(exp -14) or better level. Finally, we describe atomic clock comparison experiments that can probe for a time <span class="hlt">variation</span> of the fine structure constant, alpha = e(exp 2)/2(pi)hc, at the level of 10(exp -20)/year as predicted in some Grand Unified String Theories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990042067','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990042067"><span><span class="hlt">Frequency</span> and Angular <span class="hlt">Variations</span> of Land Surface Microwave Emissivities: Can we Estimate SSM/T and AMSU Emissivities from SSM/I Emissivities?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prigent, Catherine; Wigneron, Jean-Pierre; Rossow, William B.; Pardo-Carrion, Juan R.</p> <p>1999-01-01</p> <p>To retrieve temperature and humidity profiles from SSM/T and AMSU, it is important to quantify the contribution of the Earth surface emission. So far, no global estimates of the land surface emissivities are available at SSM/T and AMSU <span class="hlt">frequencies</span> and scanning conditions. The land surface emissivities have been previously calculated for the globe from the SSM/I conical scanner between 19 and 85 GHz. To analyze the feasibility of deriving SSM/T and AMSU land surface emissivities from SSM/I emissivities, the spectral and angular <span class="hlt">variations</span> of the emissivities are studied, with the help of ground-based measurements, models and satellite estimates. Up to 100 GHz, for snow and ice free areas, the SSM/T and AMSU emissivities can be derived with useful accuracy from the SSM/I emissivities- The emissivities can be linearly interpolated in <span class="hlt">frequency</span>. Based on ground-based emissivity measurements of various surface types, a simple model is proposed to estimate SSM/T and AMSU emissivities for all zenith angles knowing only the emissivities for the vertical and horizontal polarizations at 53 deg zenith angle. The method is tested on the SSM/T-2 91.655 GHz channels. The mean difference between the SSM/T-2 and SSM/I-derived emissivities is less than or equal to 0.01 for all zenith angles with an r.m.s. difference of approx. = 0.02. Above 100 GHz, preliminary results are presented at 150 GHz, based on SSM/T-2 observations and are compared with the very few estimations available in the literature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/867321','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/867321"><span>Particle <span class="hlt">separator</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Hendricks, Charles D.</p> <p>1990-01-01</p> <p>Method and apparatus (10) are provided for <span class="hlt">separating</span> and classifying particles (48,50,56) by dispersing the particles within a fluid (52) that is upwardly flowing within a cone-shaped pipe (12) that has its large end (20) above its small end (18). Particles of similar size and shape (48,50) migrate to individual levels (A,B) within the flowing fluid. As the fluid is deflected by a plate (42) at the top end of the pipe (12), the smallest particles are collected on a shelf-like flange (40). Ever larger particles are collected as the flow rate of the fluid is increased. To prevent particle sticking on the walls (14) of the pipe (12), additional fluid is caused to flow into the pipe (12) through holes (68) that are specifically provided for that purpose. Sticking is further prevented by high <span class="hlt">frequency</span> vibrators (70) that are positioned on the apparatus (10).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70164444','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70164444"><span>Along-strike <span class="hlt">variations</span> in fault frictional properties along the San Andreas Fault near Cholame, California from joint earthquake and low-<span class="hlt">frequency</span> earthquake relocations</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Harrington, Rebecca M.; Cochran, Elizabeth S.; Griffiths, Emily M.; Zeng, Xiangfang; Thurber, Clifford H.</p> <p>2016-01-01</p> <p>Recent observations of low‐<span class="hlt">frequency</span> earthquakes (LFEs) and tectonic tremor along the Parkfield–Cholame segment of the San Andreas fault suggest slow‐slip earthquakes occur in a transition zone between the shallow fault, which accommodates slip by a combination of aseismic creep and earthquakes (<15  km depth), and the deep fault, which accommodates slip by stable sliding (>35  km depth). However, the spatial relationship between shallow earthquakes and LFEs remains unclear. Here, we present precise relocations of 34 earthquakes and 34 LFEs recorded during a temporary deployment of 13 broadband seismic stations from May 2010 to July 2011. We use the temporary array waveform data, along with data from permanent seismic stations and a new high‐resolution 3D velocity model, to illuminate the fine‐scale details of the seismicity distribution near Cholame and the relation to the distribution of LFEs. The depth of the boundary between earthquakes and LFE hypocenters changes along strike and roughly follows the 350°C isotherm, suggesting frictional behavior may be, in part, thermally controlled. We observe no overlap in the depth of earthquakes and LFEs, with an ∼5  km <span class="hlt">separation</span> between the deepest earthquakes and shallowest LFEs. In addition, clustering in the relocated seismicity near the 2004 Mw 6.0 Parkfield earthquake hypocenter and near the northern boundary of the 1857 Mw 7.8 Fort Tejon rupture may highlight areas of frictional heterogeneities on the fault where earthquakes tend to nucleate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12683992','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12683992"><span>A multi-<span class="hlt">variate</span> statistical model integrating passive sampler and meteorology data to predict the <span class="hlt">frequency</span> distributions of hourly ambient ozone (O3) concentrations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Krupa, S; Nosal, M; Ferdinand, J A; Stevenson, R E; Skelly, J M</p> <p>2003-01-01</p> <p>A multi-<span class="hlt">variate</span>, non-linear statistical model is described to simulate passive O3 sampler data to mimic the hourly <span class="hlt">frequency</span> distributions of continuous measurements using climatologic O3 indicators and passive sampler measurements. The main meteorological parameters identified by the model were, air temperature, relative humidity, solar radiation and wind speed, although other parameters were also considered. Together, air temperature, relative humidity and passive sampler data by themselves could explain 62.5-67.5% (R(2)) of the corresponding variability of the continuously measured O3 data. The final correlation coefficients (r) between the predicted hourly O3 concentrations from the passive sampler data and the true, continuous measurements were 0.819-0.854, with an accuracy of 92-94% for the predictive capability. With the addition of soil moisture data, the model can lead to the first order approximation of atmospheric O3 flux and plant stomatal uptake. Additionally, if such data are coupled to multi-point plant response measurements, meaningful cause-effect relationships can be derived in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.mayoclinic.org/diseases-conditions/separated-shoulder/home/ovc-20232317?p=1','NIH-MEDLINEPLUS'); return false;" href="http://www.mayoclinic.org/diseases-conditions/separated-shoulder/home/ovc-20232317?p=1"><span><span class="hlt">Separated</span> Shoulder</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p><span class="hlt">Separated</span> shoulder Overview By Mayo Clinic Staff A <span class="hlt">separated</span> shoulder is an injury to the ligaments that hold your collarbone (clavicle) to your shoulder blade. In a mild <span class="hlt">separated</span> shoulder, the ligaments ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013CRGeo.345..350F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013CRGeo.345..350F"><span>Estimating <span class="hlt">variation</span> in stomatal <span class="hlt">frequency</span> at intra-individual, intra-site, and inter-taxonomic levels in populations of the Leonardoxa africana (Fabaceae) complex over environmental gradients in Cameroon</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Finsinger, Walter; Dos Santos, Thibaut; McKey, Doyle</p> <p>2013-07-01</p> <p><span class="hlt">Variation</span> of stomatal <span class="hlt">frequency</span> (stomatal density and stomatal index) includes genetically-based, potentially-adaptive <span class="hlt">variation</span>, and <span class="hlt">variation</span> due to phenotypic plasticity, the degree of which may be fundamental to the ability to maintain high water-use efficiency and thus to deal with environmental change. We analysed stomatal <span class="hlt">frequency</span> and morphology (pore length, pore width) in leaves from several individuals from nine populations of four sub-species of the Leonardoxa africana complex. The dataset represents a hierarchical sampling wherein factors are nested within each level (leaves in individuals, individuals in sites, etc.), allowing estimation of the contribution of different levels to overall <span class="hlt">variation</span>, using variance-component analysis. SI showed significant <span class="hlt">variation</span> among sites ("site" is largely confounded with "sub-species"), being highest in the sub-species localized in the highest-elevation site. However, most of the observed variance was accounted for at intra-site and intra-individual levels. This variance could reflect great phenotypic plasticity, presumably in response to highly local <span class="hlt">variation</span> in micro-environmental conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/873593','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/873593"><span>Ultracapacitor <span class="hlt">separator</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Wei, Chang; Jerabek, Elihu Calvin; LeBlanc, Jr., Oliver Harris</p> <p>2001-03-06</p> <p>An ultracapacitor includes two solid, nonporous current collectors, two porous electrodes <span class="hlt">separating</span> the collectors, a porous <span class="hlt">separator</span> between the electrodes and an electrolyte occupying the pores in the electrodes and <span class="hlt">separator</span>. The electrolyte is a polar aprotic organic solvent and a salt. The porous <span class="hlt">separator</span> comprises a wet laid cellulosic material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JCrGr.455....6S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JCrGr.455....6S"><span><span class="hlt">Separation</span> behavior of impurities and selenium reduction by the reactive zone refining process using high-<span class="hlt">frequency</span> induction heating to purify Te</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shim, Moonsoo; Kim, Young-Min; Lee, Huk-Hee; Hong, Soon-Jik; Lee, Jong-Hyeon</p> <p>2016-12-01</p> <p>A zone refining processing was utilized to purify tellurium (Te) metal using a locally melted zone caused by high-<span class="hlt">frequency</span> induction heating. The travel rate of the molten zone was set as a parameter. The purification efficiency for each impurity (Bi, Sb, Sn, and Se) in the tellurium sample was analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES), and the experimental results were compared with the theoretical results furnished by the proposed model to validate its predictions. The experimental results indicated that a lower travel rate of the molten zone and repetition of passes were more efficient for purification. The effective distribution coefficient keff and the keff values of bismuth, antimony, tin, and selenium were 0.5, 0.35, 0.22, and 0.58, respectively. These elements were effective for the purification of Te by zone refining. The obtained distribution coefficient keff values of impurities can be used as standards for the purification of Te by zone refining. The Vickers hardness was measured, and a correlation between hardness and concentration was observed, with an average Vickers hardness was 62 Hv.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010ARAC....3..341S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010ARAC....3..341S"><span>Chiral <span class="hlt">Separations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stalcup, A. M.</p> <p>2010-07-01</p> <p>The main goal of this review is to provide a brief overview of chiral <span class="hlt">separations</span> to researchers who are versed in the area of analytical <span class="hlt">separations</span> but unfamiliar with chiral <span class="hlt">separations</span>. To researchers who are not familiar with this area, there is currently a bewildering array of commercially available chiral columns, chiral derivatizing reagents, and chiral selectors for approaches that span the range of analytical <span class="hlt">separation</span> platforms (e.g., high-performance liquid chromatography, gas chromatography, supercritical-fluid chromatography, and capillary electrophoresis). This review begins with a brief discussion of chirality before examining the general strategies and commonalities among all of the chiral <span class="hlt">separation</span> techniques. Rather than exhaustively listing all the chiral selectors and applications, this review highlights significant issues and differences between chiral and achiral <span class="hlt">separations</span>, providing salient examples from specific classes of chiral selectors where appropriate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790013174','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790013174"><span>Water <span class="hlt">separator</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dunn, W. F.; Austin, I. G. (Inventor)</p> <p>1964-01-01</p> <p>An apparatus for <span class="hlt">separating</span> liquids from gases or gaseous fluids is described. Features of the apparatus include: (1) the collection and removal of the moisture in the fluid is not dependent upon, or affected by gravity; (2) all the collected water is cyclically drained from the apparatus irrespective of the attitude of the <span class="hlt">separator</span>; and (3) a fluid actuator is utilized to remove the collected water from the <span class="hlt">separator</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15669158','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15669158"><span>Battery <span class="hlt">separators</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Arora, Pankaj; Zhang, Zhengming John</p> <p>2004-10-01</p> <p>The ideal battery <span class="hlt">separator</span> would be infinitesimally thin, offer no resistance to ionic transport in electrolytes, provide infinite resistance to electronic conductivity for isolation of electrodes, be highly tortuous to prevent dendritic growths, and be inert to chemical reactions. Unfortunately, in the real world the ideal case does not exist. Real world <span class="hlt">separators</span> are electronically insulating membranes whose ionic resistivity is brought to the desired range by manipulating the membranes thickness and porosity. It is clear that no single <span class="hlt">separator</span> satisfies all the needs of battery designers, and compromises have to be made. It is ultimately the application that decides which <span class="hlt">separator</span> is most suitable. We hope that this paper will be a useful tool and will help the battery manufacturers in selecting the most appropriate <span class="hlt">separators</span> for their batteries and respective applications. The information provided is purely technical and does not include other very important parameters, such as cost of production, availability, and long-term stability. There has been a continued demand for thinner battery <span class="hlt">separators</span> to increase battery power and capacity. This has been especially true for lithiumion batteries used in portable electronics. However, it is very important to ensure the continued safety of batteries, and this is where the role of the <span class="hlt">separator</span> is greatest. Thus, it is essential to optimize all the components of battery to improve the performance while maintaining the safety of these cells. <span class="hlt">Separator</span> manufacturers should work along with the battery manufacturers to create the next generation of batteries with increased reliability and performance, but always keeping safety in mind. This paper has attempted to present a comprehensive review of literature on <span class="hlt">separators</span> used in various batteries. It is evident that a wide variety of <span class="hlt">separators</span> are available and that they are critical components in batteries. In many cases, the <span class="hlt">separator</span> is one of the major factors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004ASAJ..116..566C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004ASAJ..116..566C"><span>Non-Gaussian statistics and temporal <span class="hlt">variations</span> of the ultrasound signal backscattered by blood at <span class="hlt">frequencies</span> between 10 and 58 MHz</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cloutier, Guy; Daronat, Michel; Savéry, David; Garcia, Damien; Durand, Louis-Gilles; Foster, F. Stuart</p> <p>2004-07-01</p> <p>Very little is known about the blood backscattering behavior and signal statistics following flow stoppage at <span class="hlt">frequencies</span> higher than 10 MHz. Measurements of the radio <span class="hlt">frequency</span> (rf) signals backscattered by normal human blood (hematocrit=40%, temperature=37 °C) were performed in a tube flow model at mean <span class="hlt">frequencies</span> varying between 10 and 58 MHz. The range of increase of the backscattered power during red blood cell (RBC) rouleau formation was close to 15 dB at 10 and 36 MHz, and dropped, for the same blood samples, below 8 dB at 58 MHz. Increasing the <span class="hlt">frequency</span> from 10 to 58 MHz raised the slope of the power changes at the beginning of the kinetics of aggregation, and could emphasize the non-Gaussian behavior of the rf signals interpreted in terms of the K and Nakagami statistical models. At 36 and 58 MHz, significant increases of the kurtosis coefficient, and significant reductions of the Nakagami parameter were noted during the first 30 s of flow stoppage. In conclusion, increasing the transducer <span class="hlt">frequency</span> reduced the magnitude of the backscattered power changes attributed to the phenomenon of RBC aggregation, but improved the detection of rapid growth in aggregate sizes and non-Gaussian statistical behavior.</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_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" 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_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</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="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790000021&hterms=hartop&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D20%26Ntt%3Dhartop','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790000021&hterms=hartop&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D20%26Ntt%3Dhartop"><span>Signal <span class="hlt">separator</span> for dual-<span class="hlt">frequency</span> antenna</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hartop, R. W.</p> <p>1979-01-01</p> <p>Replacement for dichroic plate reduces noise. Besides being easier to install, flange is less expensive to fabricate. Most important, the flange reduces antenna contribution to system noise; whereas, dichroic plate increases noise temperature by 2 or 3 degrees.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GeoRL..41.4442T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeoRL..41.4442T"><span>Features of amplitude and Doppler <span class="hlt">frequency</span> <span class="hlt">variation</span> of ELF/VLF waves generated by "beat-wave" HF heating at high latitudes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tereshchenko, E. D.; Shumilov, O. I.; Kasatkina, E. A.; Gomonov, A. D.</p> <p>2014-07-01</p> <p>Observations of extremely low <span class="hlt">frequency</span> (ELF, 3-3000 Hz) radio waves generated by a "beat-wave" (BW) high <span class="hlt">frequency</span> (~ 4.04-4.9 MHz) ionospheric heating are presented. ELF waves were registered with the ELF receiver located at Lovozero (68°N, 35°E), 660 km east from the European Incoherent Scatter Tromso heating facility (69.6°N, 19.2°E). <span class="hlt">Frequency</span> shifts between the generated beat-wave and received ELF waves were detected in all sessions. It is shown that the amplitudes of ELF waves depend on the auroral electrojet current strength. Our results showing a strong dependence of ELF signal intensities on the substorm development seem to support the conclusion that electrojet currents may affect the BW generation of ELF/VLF waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22725666','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22725666"><span><span class="hlt">Variation</span> in adult sex ratio alters the association between courtship, mating <span class="hlt">frequency</span> and paternity in the lek-forming fruitfly Ceratitis capitata.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Leftwich, P T; Edward, D A; Alphey, L; Gage, M J G; Chapman, T</p> <p>2012-09-01</p> <p>The intensity with which males deliver courtship and the <span class="hlt">frequency</span> with which they mate are key components of male reproductive success. However, we expect the strength of the relationship between these traits and a male's overall paternity to be strongly context dependent, for example to be altered significantly by the extent of post-mating competition. We tested this prediction in a lekking insect, Ceratitis capitata (medfly). We examined the effect of manipulating the sex ratio from male- to female-biased (high and low male competition, respectively) on courtship behaviour, mating <span class="hlt">frequency</span> and paternity of focal males. Under high male competition, focal males delivered significantly more courtship but gained lower paternity than under lower competition. Paternity was positively associated with mating <span class="hlt">frequency</span> and small residual testes size. However, the association between mating <span class="hlt">frequency</span> and paternity was significantly stronger under low competition. We conclude that manipulation of sex ratio significantly altered the predictors of mating success and paternity. The relationship between pre- and post-mating success is therefore plastic and alters according to the prevailing level of competition. The results highlight the importance of post-copulatory processes in lekking species and illuminate selection pressures placed on insects such as medflies that are mass reared for pest control.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22542968','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22542968"><span>Disentangling the roles of history and local selection in shaping clinal <span class="hlt">variation</span> of allele <span class="hlt">frequencies</span> and gene expression in Norway spruce (Picea abies).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Jun; Källman, Thomas; Ma, Xiaofei; Gyllenstrand, Niclas; Zaina, Giusi; Morgante, Michele; Bousquet, Jean; Eckert, Andrew; Wegrzyn, Jill; Neale, David; Lagercrantz, Ulf; Lascoux, Martin</p> <p>2012-07-01</p> <p>Understanding the genetic basis of local adaptation is challenging due to the subtle balance among conflicting evolutionary forces that are involved in its establishment and maintenance. One system with which to tease apart these difficulties is clines in adaptive characters. Here we analyzed genetic and phenotypic <span class="hlt">variation</span> in bud set, a highly heritable and adaptive trait, among 18 populations of Norway spruce (Picea abies), arrayed along a latitudinal gradient ranging from 47°N to 68°N. We confirmed that <span class="hlt">variation</span> in bud set is strongly clinal, using a subset of five populations. Genotypes for 137 single-nucleotide polymorphisms (SNPs) chosen from 18 candidate genes putatively affecting bud set and 308 control SNPs chosen from 264 random genes were analyzed for patterns of genetic structure and correlation to environment. Population genetic structure was low (F(ST) = 0.05), but latitudinal patterns were apparent among Scandinavian populations. Hence, part of the observed clinal <span class="hlt">variation</span> should be attributable to population demography. Conditional on patterns of genetic structure, there was enrichment of SNPs within candidate genes for correlations with latitude. Twenty-nine SNPs were also outliers with respect to F(ST). The enrichment for clinal <span class="hlt">variation</span> at SNPs within candidate genes (i.e., SNPs in PaGI, PaPhyP, PaPhyN, PaPRR7, and PaFTL2) indicated that local selection in the 18 populations, and/or selection in the ancestral populations from which they were recently derived, shaped the observed cline. Validation of these genes using expression studies also revealed that PaFTL2 expression is significantly associated with latitude, thereby confirming the central role played by this gene in the control of phenology in plants.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4116343','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4116343"><span>AUTOMATIC <span class="hlt">FREQUENCY</span> CONTROL SYSTEM</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Hansen, C.F.; Salisbury, J.D.</p> <p>1961-01-10</p> <p>A control is described for automatically matching the <span class="hlt">frequency</span> of a resonant cavity to that of a driving oscillator. The driving oscillator is disconnected from the cavity and a secondary oscillator is actuated in which the cavity is the <span class="hlt">frequency</span> determining element. A low <span class="hlt">frequency</span> is mixed with the output of the driving oscillator and the resultant lower and upper sidebands are <span class="hlt">separately</span> derived. The <span class="hlt">frequencies</span> of the sidebands are compared with the secondary oscillator <span class="hlt">frequency</span>. deriving a servo control signal to adjust a tuning element in the cavity and matching the cavity <span class="hlt">frequency</span> to that of the driving oscillator. The driving oscillator may then be connected to the cavity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ettp.book..237W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ettp.book..237W"><span>Stereoisomers <span class="hlt">Separation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wieczorek, Piotr</p> <p></p> <p>The use of capillary electrophoresis for enantiomer <span class="hlt">separation</span> and optical purity determination is presented. The contents start with basic information about the nature of stereoizomers and the mechanism of enantioseparation using capillary electrophoresis techniques. The molecules to be <span class="hlt">separated</span> show identical chemical structure and electrochemical behavior. Therefore, the chiral recognition of enantiomers is possible only by bonding to chiral selector and the <span class="hlt">separation</span> based on very small differences in complexation energies of diastereomer complexes formed. This method is useful for this purpose due to the fact that different compounds can be used as chiral selectors. The mostly used chiral selectors like cyclodextrins, crown ethers, chiral surfactants, macrocyclic antibiotics, transition metal complexes, natural, and synthetic polymers and their application for this purpose is also discussed. Finally, examples of practical applications of electromigration techniques for enantiomers <span class="hlt">separation</span> and determination are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23924834','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23924834"><span>Galactosemia in the Turkish population with a high <span class="hlt">frequency</span> of Q188R mutation and distribution of Duarte-1 and Duarte-2 <span class="hlt">variations</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Özgül, Rıza Köksal; Güzel-Ozantürk, Ayşegül; Dündar, Halil; Yücel-Yılmaz, Didem; Coşkun, Turgay; Sivri, Serap; Aydoǧdu, Sultan; Tokatlı, Ayşegül; Dursun, Ali</p> <p>2013-10-01</p> <p>Classical galactosemia is an inherited recessive disorder of galactose metabolism caused by deficiency of the enzyme galactose-1-phosphate uridyl transferase (GALT), which is caused by mutations in the GALT gene. In this study, 56 Turkish patients diagnosed with galactosemia were screened for GALT gene mutations using Affymetrix resequencing microarrays. Eleven types of mutations were detected in these patients, including two novel mutations (R258G and G310fsX49) and nine recurrent mutations. We detected six patients who were homozygous for the E340* mutation and for N314D, L218L silent substitutions (Duarte-1 variant) in this study. The haplotype E340*, N314D and L218L has been reported only in Turkish patients, which suggests that the E340* mutation is specific for our population and might be spread by a Turk ancestor. In patients, the Duarte-1 allele was found with a <span class="hlt">frequency</span> of 10.71%, whereas the Duarte-2 allele was not detected. Duarte-1 and Duarte-2 alleles were found to be present at a <span class="hlt">frequency</span> of 2.3% and 1.4%, respectively, in the screening of 105 healthy individuals. Considering all detected mutations, it is a very important finding that exons 6 and 10 of the GALT gene account for 79% of all mutant alleles in the Turkish population. The most common mutation is Q188R, with a <span class="hlt">frequency</span> of 55.35%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6451584','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6451584"><span>Mist <span class="hlt">separator</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Moran, T.M.</p> <p>1984-04-17</p> <p>An apparatus for the removal of particulates from a flowing gas stream and a process for its use are provided. A perforated screen <span class="hlt">separator</span> formed as a plate having parallel rows of perforations formed by pushing alternating strips of the plate material forward and backward from the plane of the plate is used. The perforated screen <span class="hlt">separator</span> may be used alone or with a fiber bed mist eliminator for increased particulate removal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4523739','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4523739"><span><span class="hlt">Variations</span> of high <span class="hlt">frequency</span> parameter of heart rate variability following osteopathic manipulative treatment in healthy subjects compared to control group and sham therapy: randomized controlled trial</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ruffini, Nuria; D'Alessandro, Giandomenico; Mariani, Nicolò; Pollastrelli, Alberto; Cardinali, Lucia; Cerritelli, Francesco</p> <p>2015-01-01</p> <p>Context: Heart Rate Variability (HRV) indicates how heart rate changes in response to inner and external stimuli. HRV is linked to health status and it is an indirect marker of the autonomic nervous system (ANS) function. Objective: To investigate the influence of osteopathic manipulative treatment (OMT) on cardiac autonomic modulation in healthy subjects, compared with sham therapy and control group. Methods: Sixty-six healthy subjects, both male and female, were included in the present 3-armed randomized placebo controlled within subject cross-over single blinded study. Participants were asymptomatic adults (26.7 ± 8.4 y, 51% male, BMI 18.5 ± 4.8), both smokers and non-smokers and not on medications. At enrollment subjects were randomized in three groups: A, B, C. Standardized structural evaluation followed by a patient need-based osteopathic treatment was performed in the first session of group A and in the second session of group B. Standardized evaluation followed by a protocoled sham treatment was provided in the second session of group A and in the first session of group B. No intervention was performed in the two sessions of group C, acting as a time-control. The trial was registered on clinicaltrials.gov identifier: NCT01908920. Main Outcomes Measures: HRV was calculated from electrocardiography before, during and after the intervention, for a total amount time of 25 min and considering <span class="hlt">frequency</span> domain as well as linear and non-linear methods as outcome measures. Results: OMT engendered a statistically significant increase of parasympathetic activity, as shown by High <span class="hlt">Frequency</span> power (p < 0.001), expressed in normalized and absolute unit, and possibly decrease of sympathetic activity, as revealed by Low <span class="hlt">Frequency</span> power (p < 0.01); results also showed a reduction of Low <span class="hlt">Frequency</span>/High <span class="hlt">Frequency</span> ratio (p < 0.001) and Detrended fluctuation scaling exponent (p < 0.05). Conclusions: Findings suggested that OMT can influence ANS activity increasing</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JLTP..184..137A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JLTP..184..137A"><span>Crosstalk in a KID Array Caused by the Thickness <span class="hlt">Variation</span> of Superconducting Metal</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adane, A.; Boucher, C.; Coiffard, G.; Leclercq, S.; Schuster, K. F.; Goupy, J.; Calvo, M.; Hoarau, C.; Monfardini, A.</p> <p>2016-07-01</p> <p>The work presented in this paper is focused on the improvement of the kinetic detectors used on NIKA2 instrument (New IRAM KID array 2). Based on the simulation and low temperature measurements, it aims at showing how the <span class="hlt">variations</span> of the superconducting metal corrupt the <span class="hlt">frequency</span> comb of the kinetic Inductance detectors (KID) in the <span class="hlt">frequency</span> range (between 1 and 3 GHz), i.e., how the superconducting metal inhomogeneity induces the resonance-to-resonance cross-coupling which deteriorates the homogeneity of the resonance quality factor and the <span class="hlt">frequency</span> resonance <span class="hlt">separation</span>. Solutions are then proposed to fight against the effect of these metallic <span class="hlt">variations</span> when designing the KID array.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014NPGeo..21.1185C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014NPGeo..21.1185C"><span>Dependence of sandpile avalanche <span class="hlt">frequency</span>-size distribution on coverage extent and compactness of embedded toppling threshold heterogeneity: implications for the <span class="hlt">variation</span> of Gutenberg-Richter b value</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chiao, L.-Y.; Liu, Q.</p> <p>2014-12-01</p> <p>The effects of the spatiotemporal evolution of failure threshold heterogeneity on the dynamics of fault criticality, and thus on regional seismogenesis, have attracted strong interest in the field of regional seismotectonics. The heterogeneity might be a manifestation of the macroscopic distribution and multiscale strength <span class="hlt">variation</span> of asperities, the distinct regional stress level, and (microscopically) heterogeneous fault surface roughness or friction regimes. In this study, rather than attempting to mimic the complex microscale slipping physics on a fault surface, sandpile cellular automata were implemented with a straightforward toppling rule. The objective is to examine the influence of distinct configurations of the embedded heterogeneous toppling threshold field on the global system avalanche event statistics. The examination results revealed that increasing the coverage extent and decreasing the compactness of the heterogeneous failure threshold, rather than the magnitude, range of contrast, diversity, or the geometric configuration of the threshold heterogeneity, leads to a systematic increase in the scaling exponent of the avalanche event power law statistics, implying the importance of mutual interaction among toppling sites with distinct thresholds. For tectonic provinces with differing stress regimes evolving spatio temporally, it is postulated that the distinct extent and compactness of the heterogeneous failure threshold are critical factors that manifest in the reported dynamic <span class="hlt">variations</span> of seismicity scaling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2001/0042/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2001/0042/report.pdf"><span>Map <span class="hlt">Separates</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>,</p> <p>2001-01-01</p> <p>U.S. Geological Survey (USGS) topographic maps are printed using up to six colors (black, blue, green, red, brown, and purple). To prepare your own maps or artwork based on maps, you can order <span class="hlt">separate</span> black-and-white film positives or negatives for any color printed on a USGS topographic map, or for one or more of the groups of related features printed in the same color on the map (such as drainage and drainage names from the blue plate.) In this document, examples are shown with appropriate ink color to illustrate the various <span class="hlt">separates</span>. When purchased, <span class="hlt">separates</span> are black-and-white film negatives or positives. After you receive a film <span class="hlt">separate</span> or composite from the USGS, you can crop, enlarge or reduce, and edit to add or remove details to suit your special needs. For example, you can adapt the <span class="hlt">separates</span> for making regional and local planning maps or for doing many kinds of studies or promotions by using the features you select and then printing them in colors of your choice.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20119850','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20119850"><span>Seasonal <span class="hlt">Variation</span> in <span class="hlt">Frequency</span> of Isolation of Ophiosphaerella korrae from Bermudagrass Roots in Mississippi and Pathogenicity and Optimal Growth of Selected Isolates.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Perry, D Hunter; Tomaso-Peterson, Maria; Baird, Richard</p> <p>2010-05-01</p> <p>Isolation <span class="hlt">frequency</span> of Ophiosphaerella korrae (spring dead spot pathogen) from Cynodon dactylon (bermudagrass) roots at a golf course near West Point, Mississippi, was monitored over a 3-year investigation. Laboratory and greenhouse experiments were conducted to determine optimal temperatures for the growth of selected O. korrae isolates collected from the field study and to evaluate those isolates for pathogenicity potential. Isolation <span class="hlt">frequencies</span> of the pathogen from naturally infested root samples were significantly higher in the winter and spring and lowest in the fall regardless of cultural, nutrient, and chemical treatments. Annual soil temperatures ranged between 8 and 29 degrees C, and no correlation was observed between temperature and percent isolation of O. korrae. Optimal in vitro growth of selected O. korrae isolates ranged from 21 to 25 degrees C. Root discoloration was significantly greater in the presence of O. korrae compared to non-inoculated roots in greenhouse studies. Results of this study confirm and are the first to document that O. korrae naturally infests roots throughout the bermudagrass growth cycle, but factors other than temperature and management practices may influence O. korrae in situ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JASTP..80..296S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JASTP..80..296S"><span>Multi-scale harmonic model for solar and climate cyclical <span class="hlt">variation</span> throughout the Holocene based on Jupiter-Saturn tidal <span class="hlt">frequencies</span> plus the 11-year solar dynamo cycle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scafetta, Nicola</p> <p>2012-05-01</p> <p>The Schwabe <span class="hlt">frequency</span> band of the Zurich sunspot record since 1749 is found to be made of three major cycles with periods of about 9.98, 10.9 and 11.86 years. The side <span class="hlt">frequencies</span> appear to be closely related to the spring tidal period of Jupiter and Saturn (range between 9.5 and 10.5 years, and median 9.93 years) and to the tidal sidereal period of Jupiter (about 11.86 years). The central cycle may be associated to a quasi-11-year solar dynamo cycle that appears to be approximately synchronized to the average of the two planetary <span class="hlt">frequencies</span>. A simplified harmonic constituent model based on the above two planetary tidal <span class="hlt">frequencies</span> and on the exact dates of Jupiter and Saturn planetary tidal phases, plus a theoretically deduced 10.87-year central cycle reveals complex quasi-periodic interference/beat patterns. The major beat periods occur at about 115, 61 and 130 years, plus a quasi-millennial large beat cycle around 983 years. We show that equivalent synchronized cycles are found in cosmogenic records used to reconstruct solar activity and in proxy climate records throughout the Holocene (last 12,000 years) up to now. The quasi-secular beat oscillations hindcast reasonably well the known prolonged periods of low solar activity during the last millennium such as the Oort, Wolf, Spörer, Maunder and Dalton minima, as well as the 17 115-year long oscillations found in a detailed temperature reconstruction of the Northern Hemisphere covering the last 2000 years. The millennial three-<span class="hlt">frequency</span> beat cycle hindcasts equivalent solar and climate cycles for 12,000 years. Finally, the harmonic model herein proposed reconstructs the prolonged solar minima that occurred during 1900-1920 and 1960-1980 and the secular solar maxima around 1870-1890, 1940-1950 and 1995-2005 and a secular upward trending during the 20th century: this modulated trending agrees well with some solar proxy model, with the ACRIM TSI satellite composite and with the global surface temperature</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4303005','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4303005"><span>ISOTOPE <span class="hlt">SEPARATORS</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Bacon, C.G.</p> <p>1958-08-26</p> <p>An improvement is presented in the structure of an isotope <span class="hlt">separation</span> apparatus and, in particular, is concerned with a magnetically operated shutter associated with a window which is provided for the purpose of enabling the operator to view the processes going on within the interior of the apparatus. The shutier is mounted to close under the force of gravity in the absence of any other force. By closing an electrical circuit to a coil mouated on the shutter the magnetic field of the isotope <span class="hlt">separating</span> apparatus coacts with the magnetic field of the coil to force the shutter to the open position.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/863152','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/863152"><span>Isotope <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Bartlett, Rodney J.; Morrey, John R.</p> <p>1978-01-01</p> <p>A method and apparatus is described for <span class="hlt">separating</span> gas molecules containing one isotope of an element from gas molecules containing other isotopes of the same element in which all of the molecules of the gas are at the same electronic state in their ground state. Gas molecules in a gas stream containing one of the isotopes are selectively excited to a different electronic state while leaving the other gas molecules in their original ground state. Gas molecules containing one of the isotopes are then deflected from the other gas molecules in the stream and thus physically <span class="hlt">separated</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21071057','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21071057"><span>Temporal and geographical genetic <span class="hlt">variation</span> in the amphipod Melita plumulosa (Crustacea: Melitidae): Link of a localized change in haplotype <span class="hlt">frequencies</span> to a chemical spill.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chung, Pann Pann; Hyne, Ross V; Mann, Reinier M; Ballard, J William O</p> <p>2011-02-01</p> <p>Anthropogenic effects such as contamination affect the genetic structure of populations. This study examined the temporal and geographical patterns of genetic diversity among populations of the benthic crustacean amphipod Melita plumulosa in the Parramatta River (Sydney, Australia), following an industrial chemical spill. The spill of an acrylate/methacrylate co-polymer in naphtha solvent occurred in July 2006. M. plumulosa were sampled temporally between December 2006 and November 2009 and spatially in November 2009. Genetic <span class="hlt">variation</span> was examined at the mitochondrial cytochrome c oxidase subunit I locus. Notably, nucleotide diversity was low and Tajima's D was significantly negative amongst amphipods collected immediately downstream from the spill for 10 months. We hypothesize that the spill had a significant localized effect on the genetic diversity of M. plumulosa. Alternate explanations include an alternate and unknown toxicant or a localized sampling bias. Future proposed studies will dissect these alternatives.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMGC22E..01S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMGC22E..01S"><span>Harmonic model for solar and climate cyclical <span class="hlt">variation</span> throughout the Holocene based on Jupiter-Saturn tidal <span class="hlt">frequencies</span> plus the 11-year solar dynamo cycle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scafetta, N.</p> <p>2012-12-01</p> <p>We show that the Schwabe <span class="hlt">frequency</span> band of the Zurich sunspot record since 1749 is made of three major cycles that are closely related to the spring tidal period of Jupiter and Saturn (~9.93 year), to the tidal sidereal period of Jupiter (about 11.86 years) and to a central cycle that may be associated to a quasi-11-year solar dynamo cycle. The central harmonic is approximately synchronized to the average of the two planetary <span class="hlt">frequencies</span>. A harmonic model based on the above two planetary tidal <span class="hlt">frequencies</span> and on the exact dates of Jupiter and Saturn planetary tidal phases, plus a theoretically deduced 10.87-year central cycle reveals major beat periods occurring at about 115, 61 and 130 years, plus a quasi-millennial large beat cycle around 983 years. Equivalent synchronized cycles are found in cosmogenic solar proxy records used to reconstruct solar activity and in proxy climate records throughout the Holocene (last 12,000 years) up to now. The quasi-secular beat oscillations hindcast reasonably well the known prolonged periods of low solar activity during the last millennium such as the Oort, Wolf, Sporer, Maunder and Dalton minima, as well as the 17 115-year long oscillations found in a detailed temperature reconstruction of the Northern Hemisphere covering the last 2000 years. The millennial three-<span class="hlt">frequency</span> beat cycle hindcasts equivalent solar and climate cycles for 12,000 years. Finally, the harmonic model herein proposed reconstructs the prolonged solar minima around 1900-1920 and 1960-1980, the secular solar maxima around 1870-1890, 1940-1950 and 1995-2005, and a secular upward trending during the 20th century. The latter modulated trending agrees well with some solar proxy model, with the ACRIM TSI satellite composite and with the global surface temperature modulation since 1850. The model forecasts a new prolonged solar minimum during 2020-2045, which is produced by the minima of both the 61 and 115-year reconstructed cycles. Finally, the model predicts</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3718373','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3718373"><span>A Mechanism for <span class="hlt">Frequency</span> Modulation in Songbirds Shared with Humans</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Margoliash, Daniel</p> <p>2013-01-01</p> <p>In most animals that vocalize, control of fundamental <span class="hlt">frequency</span> is a key element for effective communication. In humans, subglottal pressure controls vocal intensity but also influences fundamental <span class="hlt">frequency</span> during phonation. Given the underlying similarities in the biomechanical mechanisms of vocalization in humans and songbirds, songbirds offer an attractive opportunity to study <span class="hlt">frequency</span> modulation by pressure. Here, we present a novel technique for dynamic control of subsyringeal pressure in zebra finches. By regulating the opening of a custom-built fast valve connected to the air sac system, we achieved partial or total silencing of specific syllables, and could modify syllabic acoustics through more complex manipulations of air sac pressure. We also observed that more nuanced pressure <span class="hlt">variations</span> over a limited interval during production of a syllable concomitantly affected the <span class="hlt">frequency</span> of that syllable segment. These results can be explained in terms of a mathematical model for phonation that incorporates a nonlinear description for the vocal source capable of generating the observed <span class="hlt">frequency</span> modulations induced by pressure <span class="hlt">variations</span>. We conclude that the observed interaction between pressure and <span class="hlt">frequency</span> was a feature of the source, not a result of feedback control. Our results indicate that, beyond regulating phonation or its absence, regulation of pressure is important for control of fundamental <span class="hlt">frequencies</span> of vocalizations. Thus, although there are <span class="hlt">separate</span> brainstem pathways for syringeal and respiratory control of song production, both can affect airflow and <span class="hlt">frequency</span>. We hypothesize that the control of pressure and <span class="hlt">frequency</span> is combined holistically at higher levels of the vocalization pathways. PMID:23825417</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23825417','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23825417"><span>A mechanism for <span class="hlt">frequency</span> modulation in songbirds shared with humans.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Amador, Ana; Margoliash, Daniel</p> <p>2013-07-03</p> <p>In most animals that vocalize, control of fundamental <span class="hlt">frequency</span> is a key element for effective communication. In humans, subglottal pressure controls vocal intensity but also influences fundamental <span class="hlt">frequency</span> during phonation. Given the underlying similarities in the biomechanical mechanisms of vocalization in humans and songbirds, songbirds offer an attractive opportunity to study <span class="hlt">frequency</span> modulation by pressure. Here, we present a novel technique for dynamic control of subsyringeal pressure in zebra finches. By regulating the opening of a custom-built fast valve connected to the air sac system, we achieved partial or total silencing of specific syllables, and could modify syllabic acoustics through more complex manipulations of air sac pressure. We also observed that more nuanced pressure <span class="hlt">variations</span> over a limited interval during production of a syllable concomitantly affected the <span class="hlt">frequency</span> of that syllable segment. These results can be explained in terms of a mathematical model for phonation that incorporates a nonlinear description for the vocal source capable of generating the observed <span class="hlt">frequency</span> modulations induced by pressure <span class="hlt">variations</span>. We conclude that the observed interaction between pressure and <span class="hlt">frequency</span> was a feature of the source, not a result of feedback control. Our results indicate that, beyond regulating phonation or its absence, regulation of pressure is important for control of fundamental <span class="hlt">frequencies</span> of vocalizations. Thus, although there are <span class="hlt">separate</span> brainstem pathways for syringeal and respiratory control of song production, both can affect airflow and <span class="hlt">frequency</span>. We hypothesize that the control of pressure and <span class="hlt">frequency</span> is combined holistically at higher levels of the vocalization pathways.</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_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" 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_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</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="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4837839','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4837839"><span><span class="hlt">SEPARATION</span> PROCESS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Stoughton, R.W.</p> <p>1961-10-24</p> <p>A process for <span class="hlt">separating</span> tetravalent plutonium from aqueous solutions and from niobium and zirconium by precipitation on lanthanum oxalate is described. The oxalate ions of the precipitate may be decomposed by heating in the presence of an oxidizing agent, forming a plutonium compound readily soluble in acid. (AEC)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930007703','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930007703"><span>Plasma <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Steurer, Wolfgang</p> <p>1992-01-01</p> <p>This process employs a thermal plasma for the <span class="hlt">separation</span> and production of oxygen and metals. It is a continuous process that requires no consumables and relies entirely on space resources. The almost complete absence of waste renders it relatively clean. It can be turned on or off without any undesirable side effects or residues. The prime disadvantage is its high power consumption.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA531469','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA531469"><span><span class="hlt">Frequency</span> Diverse Array Radar</span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>2010-09-01</p> <p>the methods for electronic scanning of antenna systems. Techniques that have been studied in this connection include <span class="hlt">frequency</span> <span class="hlt">variation</span>, phase shift...an array antenna instantaneously into a desired direction where no mechanical mechanism is involved in the scanning process. Electronic scanning... methods including phase scanning, time delay scanning, and <span class="hlt">frequency</span> scanning have been used in various radar applications; however new and cheaper</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25708724','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25708724"><span>Dosimetry of infant exposure to power-<span class="hlt">frequency</span> magnetic fields: <span class="hlt">variation</span> of 99th percentile induced electric field value by posture and skin-to-skin contact.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Congsheng; Wu, Tongning</p> <p>2015-04-01</p> <p>Infant exposure to 50 Hz magnetic fields from power lines was numerically analyzed in this study. Dosimetric variability due to posture and skin-to-skin contact was evaluated using human anatomical models including a recently developed model of a 12-months-old infant. As proposed by the International Commission on Non-Ionizing Radiation Protection, the induced E-field strength (99th percentile value, E99 ) for the central nerve systems (E99_CNS ) and peripheral nerve system (E99_PNS ), were used as metrics. Results showed that the single (free of contact with others) infant model has lower E99 (E99_CNS and E99_PNS inclusive) compared with single adult and child models when exposed to the same power-<span class="hlt">frequency</span> magnetic field. Also, studied postures of sitting, standing, or arm-up, would not change E99 _PNS . However, skin-to-skin contact with other models could significantly raise induced E-field strength in the infant (e.g., contact on 0.93% of the infant's total surface increased E99_PNS by 213%). Simulations with canonical models were conducted to assess different factors contributing to the E99 enhancement. Results indicated the importance of thoroughly investigating the conservativeness of current safety guidelines in the case of skin-to-skin contact, especially with infants.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1176690','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1176690"><span>Gas <span class="hlt">separating</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Gollan, Arye Z.</p> <p>1990-12-25</p> <p>Feed gas is directed tangentially along the non-skin surface of gas <span class="hlt">separation</span> membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/866546','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/866546"><span>Gas <span class="hlt">separating</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Gollan, Arye</p> <p>1988-01-01</p> <p>Feed gas is directed tangentially along the non-skin surface of gas <span class="hlt">separation</span> membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6801183','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6801183"><span>Dust <span class="hlt">separator</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Borow, H.</p> <p>1987-01-27</p> <p>This patent describes a gas filter apparatus for <span class="hlt">separating</span> solids from a gas stream comprising a housing having a top, base, and side walls defining a chamber, a partition wall extending across the chamber and <span class="hlt">separating</span> the chamber into an upper compartment and a lower compartment. A gas inlet conveyor tube in the chamber passes downwardly of the partition and into the lower compartment, the portion of the conveyor tube passing through the upper compartment being impervious and the portion of the conveyor tube extending downwardly into the lower compartment being provided with exit means including exit apertures at least in the area of the conveyor tube adjacent the partition wall. The partition wall is provided with openings surrounding the conveyor tube and communicates the lower compartment with the upper compartment. A filter means in the form of filter tubes covers each opening in the partition wall and extends downwardly in the lower compartment and parallel to the conveyor tube, at least one gas outlet communicating with the upper compartment. A suction means is associated with the gas outlet to provide a reduced pressure within the chamber. A discharge means at the base of the housing is associated with the lower compartment for discharging solid matter <span class="hlt">separated</span> from the gas stream. The solid laden gas is conveyed into the lower compartment downwardly by the conveying tube and the gas of the stream is drawn from the conveyor tube immediately past the partition, through the surrounding filter tubes in order to prevent the formation of counter gas flows to the gravity discharge of the solids being <span class="hlt">separated</span> from the gas stream.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/865826','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/865826"><span><span class="hlt">Separation</span> system</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Rubin, Leslie S.</p> <p>1986-01-01</p> <p>A <span class="hlt">separation</span> system for dewatering radioactive waste materials includes a disposal container, drive structure for receiving the container, and means for releasably attaching the container to the drive structure. <span class="hlt">Separation</span> structure disposed in the container adjacent the inner surface of the side wall structure retains solids while allowing passage of liquids. Inlet port structure in the container top wall is normally closed by first valve structure that is centrifugally actuated to open the inlet port and discharge port structure at the container periphery receives liquid that passes through the <span class="hlt">separation</span> structure and is normally closed by second valve structure that is centrifugally actuated to open the discharge ports. The container also includes coupling structure for releasable engagement with the centrifugal drive structure. Centrifugal force produced when the container is driven in rotation by the drive structure opens the valve structures, and radioactive waste material introduced into the container through the open inlet port is dewatered, and the waste is compacted. The ports are automatically closed by the valves when the container drum is not subjected to centrifugal force such that containment effectiveness is enhanced and exposure of personnel to radioactive materials is minimized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1108984','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1108984"><span>Spatial and temporal <span class="hlt">variations</span> of new particle formation in East Asia using an NPF-explicit WRF-chem model: North-south contrast in new particle formation <span class="hlt">frequency</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Matsui, H.; Koike, Makoto; Takegawa, Nobuyuki; Kondo, Yutaka; Takami, A.; Takamura, T.; Yoon, Soh-joung; Kim, S. W.; Lim, Hyuntae; Fast, Jerome D.</p> <p>2013-10-27</p> <p>The new particle formation (NPF)-explicit version of the WRF-chem model, which we developed recently, can calculate the growth and sink of nucleated clusters explicitly with 20 aerosol size bins from 1 nm to 10 μm. In this study, the model is used to understand spatial and temporal <span class="hlt">variations</span> of the <span class="hlt">frequency</span> of NPF events and the concentrations of aerosols (condensation nuclei, CN) and cloud condensation nuclei (CCN) within the boundary layer in East Asia in spring 2009. Model simulations show distinct north-south contrast in the <span class="hlt">frequency</span> and mechanism of NPF in East Asia. NPF mostly occurred over limited periods and regions between 30° and 45°N, such as northeast China, Korea, and Japan, including regions around active volcanoes (Miyakejima and Sakurajima). At these latitudes, NPF was considerably suppressed by high concentrations of preexisting particles under stagnant air conditions associated with high-pressure systems, while nucleation occurred more extensively on most days during the simulation period. Conversely, neither nucleation nor NPF occurred frequently south of 30°N because of lower SO2 emissions and H2SO4 concentrations. The period-averaged NPF <span class="hlt">frequency</span> was 3 times higher at latitudes of 30° - 45°N than at latitudes of 20° - 30°N. The north-south contrast of NPF <span class="hlt">frequency</span> is validated by surface measurements in outflow regions in East Asia. The period- and domain-averaged contribution of secondary particles is estimated to be 44% for CN (> 10 nm) and 26% for CCN at a supersaturation of 1.0% in our simulation, though the contribution is highly sensitive to the magnitudes and size distributions of primary aerosol emissions and the coefficients in the nucleation parameterizations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Frequency&id=EJ1056039','ERIC'); return false;" href="http://eric.ed.gov/?q=Frequency&id=EJ1056039"><span>Parametric Effects of Word <span class="hlt">Frequency</span> in Memory for Mixed <span class="hlt">Frequency</span> Lists</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>Lohnas, Lynn J.; Kahana, Michael J.</p> <p>2013-01-01</p> <p>The "word <span class="hlt">frequency</span> paradox" refers to the finding that low <span class="hlt">frequency</span> words are better recognized than high <span class="hlt">frequency</span> words yet high <span class="hlt">frequency</span> words are better recalled than low <span class="hlt">frequency</span> words. Rather than comparing <span class="hlt">separate</span> groups of low and high <span class="hlt">frequency</span> words, we sought to quantify the functional relation between word <span class="hlt">frequency</span> and…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.4536S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.4536S"><span>Quantifying the climate change-induced <span class="hlt">variations</span> in Saskatoon's Intensity-Duration-<span class="hlt">Frequency</span> curves using stochastic rainfall generators and K-nearest neighbors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shahabul Alam, Md.; Nazemi, Alireza; Elshorbagy, Amin</p> <p>2014-05-01</p> <p>Intensity-Duration-<span class="hlt">Frequency</span> (IDF) curves are among standard design criteria for various engineering applications, such as storm water management systems. Warming climate, however, changes the extreme rainfall quantiles represented by the IDF curves. This study attempts to construct the future IDF curves under possible climate change scenarios. For this purpose, a stochastic rainfall generator is used to spatially downscale the daily projections of Global Climate Models (GCMs) from coarse grid resolution to the point scale. The stochastically downscaled daily rainfall realizations can be further disaggregated to hourly and sub-hourly rainfall series using a deterministic disaggregation scheme developed based on the K-Nearest Neighbor (K-NN) method. We applied this framework for constructing the future IDF curves in the city of Saskatoon, Canada. As a model development step, the sensitivity of the K-NN disaggregation model to the number of nearest neighbors (i.e. window size) is evaluated during the baseline periods. The optimum window size is assigned based on the performance in reproducing the historical IDF curves. The optimum windows identified for 1-hour and 5-min temporal resolutions are then used to produce the future hourly and consequently, 5-min resolution rainfall based on the K-NN simulations. By using the simulated hourly and sub-hourly rainfall series and the Generalized Extreme Value (GEV) distribution future changes in IDF curves and associated uncertainties are quantified using a large ensemble of projections obtained for the CGCM3.1 and HadCM3 based on A1B, A2 and B1 emission scenarios in case of CMIP3 and RCP2.6, RCP4.5, and RCP8.5 in case of CMIP5 datasets. The constructed IDF curves for the city of Saskatoon are then compared with corresponding historical relationships at various durations and/or return periods and are discussed based on different models, emission scenarios and/or simulation release (i.e. CMIP3 vs. CMIP5).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7168455','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/7168455"><span>Gas <span class="hlt">separating</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Gollan, A.</p> <p>1988-03-29</p> <p>Feed gas is directed tangentially along the non-skin surface of gas <span class="hlt">separation</span> membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/27737','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/27737"><span>Gas <span class="hlt">separating</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Gollan, A.Z.</p> <p>1990-12-25</p> <p>Feed gas is directed tangentially along the non-skin surface of gas <span class="hlt">separation</span> membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080023303','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080023303"><span>Spectral <span class="hlt">Separation</span> of the Turbofan Engine Coherent Combustion Noise Component</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miles, Jeffrey Hilton</p> <p>2008-01-01</p> <p>The core noise components of a dual spool turbofan engine (Honeywell TECH977) were <span class="hlt">separated</span> by the use of a coherence function. A source location technique based on adjusting the time delay between the combustor pressure sensor signal and the far-field microphone signal to maximize the coherence and remove as much <span class="hlt">variation</span> of the phase angle with <span class="hlt">frequency</span> as possible was used. While adjusting the time delay to maximize the coherence and minimize the cross spectrum phase angle <span class="hlt">variation</span> with <span class="hlt">frequency</span>, the discovery was made that for the 130 microphone a 90.027 ms time shift worked best for the <span class="hlt">frequency</span> band from 0 to 200 Hz while a 86.975 ms time shift worked best for the <span class="hlt">frequency</span> band from 200 to 400 Hz. Since the 0 to 200 Hz band signal took more time to travel the same distance, it is slower than the 200 to 400 Hz band signal. This suggests the 0 to 200 Hz coherent cross spectral density band is partly due to indirect combustion noise attributed to hot spots interacting with the turbine. The signal in the 200 to 400 Hz <span class="hlt">frequency</span> band is attributed mostly to direct combustion noise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19968425','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19968425"><span>Contour integration across spatial <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>Persike, Malte; Olzak, Lynn A; Meinhardt, Günter</p> <p>2009-12-01</p> <p>Association field models of contour integration suggest that local band-pass elements are spatially grouped to global contours within limited bands of spatial <span class="hlt">frequency</span> (Field, Hayes, & Hess, 1993). While results for local orientation and spacing <span class="hlt">variation</span> render support for AF models, effects of spatial <span class="hlt">frequency</span> (SF) have rarely been addressed. To explore whether contour integration occurs across SF, we studied human contour detection in Gabor random fields with SF jitter along the contour, and in the embedding field. Results show no impairment of contour detection when the contour elements are 1.25 octaves apart. Even with a SF <span class="hlt">separation</span> of 2.25 octaves there is only moderate impairment. Because SF tuning functions measured for contextual interactions of neighbored single band-pass elements indicate much smaller bandwidths (Polat & Sagi, 1993), the results imply that contour integration cannot rest solely on local locking among neighbored orientation and SF tuned mechanisms. Robustness across spatial <span class="hlt">frequency</span>, and across color and depth, as found recently, indicates that local orientation based grouping integrates across other basic features. This suggests an origin in not too distal brain regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22408129','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22408129"><span>Ionospheric very low <span class="hlt">frequency</span> transmitter</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kuo, Spencer P.</p> <p>2015-02-15</p> <p>The theme of this paper is to establish a reliable ionospheric very low <span class="hlt">frequency</span> (VLF) transmitter, which is also broad band. Two approaches are studied that generate VLF waves in the ionosphere. The first, classic approach employs a ground-based HF heater to directly modulate the high latitude ionospheric, or auroral electrojet. In the classic approach, the intensity-modulated HF heater induces an alternating current in the electrojet, which serves as a virtual antenna to transmit VLF waves. The spatial and temporal <span class="hlt">variations</span> of the electrojet impact the reliability of the classic approach. The second, beat-wave approach also employs a ground-based HF heater; however, in this approach, the heater operates in a continuous wave mode at two HF <span class="hlt">frequencies</span> <span class="hlt">separated</span> by the desired VLF <span class="hlt">frequency</span>. Theories for both approaches are formulated, calculations performed with numerical model simulations, and the calculations are compared to experimental results. Theory for the classic approach shows that an HF heater wave, intensity-modulated at VLF, modulates the electron temperature dependent electrical conductivity of the ionospheric electrojet, which, in turn, induces an ac electrojet current. Thus, the electrojet becomes a virtual VLF antenna. The numerical results show that the radiation intensity of the modulated electrojet decreases with an increase in VLF radiation <span class="hlt">frequency</span>. Theory for the beat wave approach shows that the VLF radiation intensity depends upon the HF heater intensity rather than the electrojet strength, and yet this approach can also modulate the electrojet when present. HF heater experiments were conducted for both the intensity modulated and beat wave approaches. VLF radiations were generated and the experimental results confirm the numerical simulations. Theory and experimental results both show that in the absence of the electrojet, VLF radiation from the F-region is generated via the beat wave approach. Additionally, the beat wave approach</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1016681','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1016681"><span>Particle <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Moosmuller, Hans [Reno, NV; Chakrabarty, Rajan K [Reno, NV; Arnott, W Patrick [Reno, NV</p> <p>2011-04-26</p> <p>Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, <span class="hlt">separate</span> the particles based on their morphology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110011185','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110011185"><span>Particle <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moosmuller, Hans (Inventor); Chakrabarty, Rajan K. (Inventor); Arnott, W. Patrick (Inventor)</p> <p>2011-01-01</p> <p>Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, <span class="hlt">separate</span> the particles based on their morphology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999ASPC..180..419S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999ASPC..180..419S"><span>Multi-<span class="hlt">Frequency</span> Synthesis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sault, R. J.; Conway, J. E.</p> <p></p> <p>Multi-<span class="hlt">frequency</span> synthesis is the practice of using visibility data measured over a range of <span class="hlt">frequencies</span> when forming a continuum image. Because observing <span class="hlt">frequency</span> is easier to vary than antenna location, it is an effective way of filling the (u,v) plane for an observation. Here we consider the artifacts in MFS images caused by source spectral <span class="hlt">variation</span>. For <span class="hlt">frequency</span> ranges of about 30%, for observations where only modest dynamic range is required, the artifacts of MFS can be completely ignored. For higher dynamic range observations, some calibration techniques and deconvolution algorithms are described which minimize the artifacts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70035508','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70035508"><span>b values and ω−γ seismic source models: Implications for tectonic stress <span class="hlt">variations</span> along active crustal fault zones and the estimation of high-<span class="hlt">frequency</span> strong ground motion</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hanks, Thomas C.</p> <p>1979-01-01</p> <p>In this study the tectonic stress along active crustal fault zones is taken to be of the form , where  is the average tectonic stress at depth y and Δσp(x, y) is a seismologically observable, essentially random function of both fault plane coordinates; the stress differences arising in the course of crustal faulting are derived from Δσp(x, y). Empirically known <span class="hlt">frequency</span> of occurrence statistics, moment-magnitude relationships, and the constancy of earthquake stress drops may be used to infer that the number of earthquakes N of dimension ≥r is of the form N ∼ 1/r2 and that the spectral composition of Δσp(x, y) is of the form , where  is the two-dimensional Fourier transform of Δσp(x, y) expressed in radial wave number k. The γ = 2 model of the far-field shear wave displacement spectrum is consistent with the spectral composition , provided that the number of contributions to the spectral representation of the radiated field at <span class="hlt">frequency</span> ƒ goes as (k/k0)2, consistent with the quasi-static <span class="hlt">frequency</span> of occurrence relation N ∼ 1/r2;k0 is a reference wave number associated with the reciprocal source dimension. <span class="hlt">Separately</span>, a variety of seismologic observations suggests that the γ = 2 model is the one generally, although certainly not always, applicable to the high-<span class="hlt">frequency</span> spectral decay of the far-field radiation of earthquakes. In this framework, then, b values near 1, the general validity of the γ = 2 model, and the constancy of earthquake stress drops independent of size are all related to the average spectral composition of. Should one of these change as a result of premonitory effects leading to failure, as has been specifically proposed for b values, it seems likely that one or all of the other characteristics will change as well from their normative values. Irrespective of these associations, the far-field, high-<span class="hlt">frequency</span> shear radiation for the γ = 2 model in the presence of anelastic attenuation may be interpreted as</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_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" 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_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</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="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=reduplication&id=ED519308','ERIC'); return false;" href="http://eric.ed.gov/?q=reduplication&id=ED519308"><span><span class="hlt">Frequency</span>, Gradience, and <span class="hlt">Variation</span> in Consonant Insertion</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>An, Young-ran</p> <p>2010-01-01</p> <p>This dissertation addresses the extent to which linguistic behavior can be described in terms of the projection of patterns from existing lexical items, through an investigation of Korean reduplication. Korean has a productive pattern of reduplication in which a consonant is inserted in a vowel-initial base, illustrated by forms such as "alok"--"t…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880014582','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880014582"><span>Acoustic emission <span class="hlt">frequency</span> discrimination</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sugg, Frank E. (Inventor); Graham, Lloyd J. (Inventor)</p> <p>1988-01-01</p> <p>In acoustic emission nondestructive testing, broadband <span class="hlt">frequency</span> noise is distinguished from narrow banded acoustic emission signals, since the latter are valid events indicative of structural flaws in the material being examined. This is accomplished by <span class="hlt">separating</span> out those signals which contain <span class="hlt">frequency</span> components both within and beyond (either above or below) the range of valid acoustic emission events. Application to acoustic emission monitoring during nondestructive bond verification and proof loading of undensified tiles on the Space Shuttle Orbiter is considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MSSP...86...75W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MSSP...86...75W"><span>Complex <span class="hlt">variational</span> mode decomposition for signal processing applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Yanxue; Liu, Fuyun; Jiang, Zhansi; He, Shuilong; Mo, Qiuyun</p> <p>2017-03-01</p> <p>Complex-valued signals occur in many areas of science and engineering and are thus of fundamental interest. The complex <span class="hlt">variational</span> mode decomposition (CVMD) is proposed as a natural and a generic extension of the original VMD algorithm for the analysis of complex-valued data in this work. Moreover, the equivalent filter bank structure of the CVMD in the presence of white noise, and the effects of initialization of center <span class="hlt">frequency</span> on the filter bank property are both investigated via numerical experiments. Benefiting from the advantages of CVMD algorithm, its bi-directional Hilbert time-<span class="hlt">frequency</span> spectrum is developed as well, in which the positive and negative <span class="hlt">frequency</span> components are formulated on the positive and negative <span class="hlt">frequency</span> planes <span class="hlt">separately</span>. Several applications in the real-world complex-valued signals support the analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19770000169&hterms=liquid+liquid+separation+methods&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dliquid%2Bliquid%2Bseparation%2Bmethods','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19770000169&hterms=liquid+liquid+separation+methods&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dliquid%2Bliquid%2Bseparation%2Bmethods"><span>Radioactive-gas <span class="hlt">separation</span> technique</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Haney, R.; King, K. J.; Nellis, D. O.; Nisson, R. S.; Robling, P.; Womack, W.</p> <p>1977-01-01</p> <p>Cryogenic technique recovers gases inexpensively. Method uses differences in vapor pressures, melting points, and boiling points of components in gaseous mixture. Series of temperature and pressure <span class="hlt">variations</span> converts gases independently to solid and liquid states, thereby simplifying <span class="hlt">separation</span>. Apparatus uses readily available cryogen and does not require expensive refrigeration equipment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160012469','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160012469"><span>Complex Signal Kurtosis and Independent Component Analysis for Wideband Radio <span class="hlt">Frequency</span> Interference Detection</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schoenwald, Adam; Mohammed, Priscilla; Bradley, Damon; Piepmeier, Jeffrey; Wong, Englin; Gholian, Armen</p> <p>2016-01-01</p> <p>Radio-<span class="hlt">frequency</span> interference (RFI) has negatively implicated scientific measurements across a wide <span class="hlt">variation</span> passive remote sensing satellites. This has been observed in the L-band radiometers SMOS, Aquarius and more recently, SMAP [1, 2]. RFI has also been observed at higher <span class="hlt">frequencies</span> such as K band [3]. Improvements in technology have allowed wider bandwidth digital back ends for passive microwave radiometry. A complex signal kurtosis radio <span class="hlt">frequency</span> interference detector was developed to help identify corrupted measurements [4]. This work explores the use of ICA (Independent Component Analysis) as a blind source <span class="hlt">separation</span> technique to pre-process radiometric signals for use with the previously developed real and complex signal kurtosis detectors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3545284','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3545284"><span><span class="hlt">Separate</span> Magnitude and Phase Regularization via Compressed Sensing</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Noll, Douglas C.; Nielsen, Jon-Fredrik; Fessler, Jeffrey A.</p> <p>2012-01-01</p> <p>Compressed sensing (CS) has been used for accelerating magnetic resonance imaging (MRI) acquisitions, but its use in applications with rapid spatial phase <span class="hlt">variations</span> is challenging, e.g., proton resonance <span class="hlt">frequency</span> shift (PRF-shift) thermometry and velocity mapping. Previously, an iterative MRI reconstruction with <span class="hlt">separate</span> magnitude and phase regularization was proposed for applications where magnitude and phase maps are both of interest, but it requires fully sampled data and unwrapped phase maps. In this paper, CS is combined into this framework to reconstruct magnitude and phase images accurately from undersampled data. Moreover, new phase regularization terms are proposed to accommodate phase wrapping and to reconstruct images with encoded phase <span class="hlt">variations</span>, e.g., PRF-shift thermometry and velocity mapping. The proposed method is demonstrated with simulated thermometry data and in-vivo velocity mapping data and compared to conventional phase corrected CS. PMID:22552571</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050215216','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050215216"><span>Impulsive Injection for Compressor Stator <span class="hlt">Separation</span> Control</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Culley, Dennis E.; Braunscheidel, Edward P.; Bright, Michelle M.</p> <p>2005-01-01</p> <p>Flow control using impulsive injection from the suction surface of a stator vane has been applied in a low speed axial compressor. Impulsive injection is shown to significantly reduce <span class="hlt">separation</span> relative to steady injection for vanes that were induced to <span class="hlt">separate</span> by an increase in vane stagger angle of 4 degrees. Injected flow was applied to the airfoil suction surface using spanwise slots pitched in the streamwise direction. Injection was limited to the near-hub region, from 10 to 36 percent of span, to affect the dominant loss due to hub leakage flow. Actuation was provided externally using high-speed solenoid valves closely coupled to the vane tip. <span class="hlt">Variations</span> in injected mass, <span class="hlt">frequency</span>, and duty cycle are explored. The local corrected total pressure loss across the vane at the lower span region was reduced by over 20 percent. Additionally, low momentum fluid migrating from the hub region toward the tip was effectively suppressed resulting in an overall benefit which reduced corrected area averaged loss through the passage by 4 percent. The injection mass fraction used for impulsive actuation was typically less than 0.1 percent of the compressor through flow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.6063L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.6063L"><span>Analysis of L5 phase <span class="hlt">variations</span> in GPS IIF satellites by the raw observation PPP approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Sha; Becker, Matthias</p> <p>2015-04-01</p> <p>GPS modernization along with Glonass modernization and the emerging Galileo and Compass system has been highly anticipated by every GNSS user since several years. The third civilian L5 signal transmitted by the modernized GPS satellites brings us to the GNSS multi-<span class="hlt">frequency</span> era. The first GPS IIF satellite was launched in May 2010, until now there are eight block IIF satellites in service and the remaining four IIF satellites are planned to be launched by 2016. The introduction of the third <span class="hlt">frequency</span> to GPS and the usage of advanced atomic clocks not only provide the users more possibilities but also enable higher positioning accuracy. Nevertheless phase <span class="hlt">variations</span> are found on the new L5 observation of GPS SVN62. Further investigations suggest that the <span class="hlt">variations</span> of this satellite are strongly dependent on the satellite inner temperature <span class="hlt">variation</span> caused by sun illumination. Besides achieving precise positioning accuracy, PPP is also frequently used as a tool to analyze and evaluate various GNSS errors, for instance, tropospheric delays and receiver clock errors. Other than with differential GNSS, it is possible to <span class="hlt">separate</span> different errors and to identify the error sources with PPP. Conventional PPP is based on the ionosphere-free linear combination, in order to eliminate the first-order ionospheric delays. However only dual <span class="hlt">frequencies</span> can be used to build ionosphere-free linear combination, which leads to the waste of the information on the third <span class="hlt">frequency</span>. Furthermore, the <span class="hlt">frequency</span> dependent errors can not be <span class="hlt">separated</span> and traced. A new PPP approach that avoids using any linear combination is proposed recently, which is called the raw observation PPP. One advantage of the raw observation PPP approach is that data of all <span class="hlt">frequencies</span> and all GNSS systems can be jointly used. In addition, the <span class="hlt">frequency</span> dependent errors are possible to be <span class="hlt">separated</span>, identified and analyzed. In this paper the raw observation PPP is utilized to analyze the phase <span class="hlt">variations</span> on L5</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://medlineplus.gov/ency/patientinstructions/000562.htm','NIH-MEDLINEPLUS'); return false;" href="https://medlineplus.gov/ency/patientinstructions/000562.htm"><span>Shoulder <span class="hlt">separation</span> - aftercare</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p><span class="hlt">Separated</span> shoulder - aftercare; Acromioclavicular joint <span class="hlt">separation</span> - aftercare; A/C <span class="hlt">separation</span> - aftercare ... Most shoulder <span class="hlt">separation</span> injuries are caused by falling onto the shoulder. This causes a tear in the tissue that connects the ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5131883','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5131883"><span>A Deep Ensemble Learning Method for Monaural Speech <span class="hlt">Separation</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>Zhang, Xiao-Lei; Wang, DeLiang</p> <p>2016-01-01</p> <p>Monaural speech <span class="hlt">separation</span> is a fundamental problem in robust speech processing. Recently, deep neural network (DNN)-based speech <span class="hlt">separation</span> methods, which predict either clean speech or an ideal time-<span class="hlt">frequency</span> mask, have demonstrated remarkable performance improvement. However, a single DNN with a given window length does not leverage contextual information sufficiently, and the differences between the two optimization objectives are not well understood. In this paper, we propose a deep ensemble method, named multicontext networks, to address monaural speech <span class="hlt">separation</span>. The first multicontext network averages the outputs of multiple DNNs whose inputs employ different window lengths. The second multicontext network is a stack of multiple DNNs. Each DNN in a module of the stack takes the concatenation of original acoustic features and expansion of the soft output of the lower module as its input, and predicts the ratio mask of the target speaker; the DNNs in the same module employ different contexts. We have conducted extensive experiments with three speech corpora. The results demonstrate the effectiveness of the proposed method. We have also compared the two optimization objectives systematically and found that predicting the ideal time-<span class="hlt">frequency</span> mask is more efficient in utilizing clean training speech, while predicting clean speech is less sensitive to SNR <span class="hlt">variations</span>. PMID:27917394</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/863597','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/863597"><span>Isotope <span class="hlt">separation</span> apparatus</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Arnush, Donald; MacKenzie, Kenneth R.; Wuerker, Ralph F.</p> <p>1980-01-01</p> <p>Isotope <span class="hlt">separation</span> apparatus consisting of a plurality of cells disposed adjacent to each other in an evacuated container. A common magnetic field is established extending through all of the cells. A source of energetic electrons at one end of the container generates electrons which pass through the cells along the magnetic field lines. Each cell includes an array of collector plates arranged in parallel or in tandem within a common magnetic field. Sets of collector plates are disposed adjacent to each other in each cell. Means are provided for differentially energizing ions of a desired isotope by applying energy at the cyclotron resonant <span class="hlt">frequency</span> of the desired isotope. As a result, the energized desired ions are preferentially collected by the collector plates.</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 Link Land Test Stations § 87.287 <span class="hlt">Frequencies</span>. (a) The <span class="hlt">frequencies</span> assignable to aircraft data link..., 136.925 MHz, 136.950 MHz, and 136.975 MHz. Interstitial <span class="hlt">frequencies</span> <span class="hlt">separated</span> by 8.33 kilohertz...</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('https://www.gpo.gov/fdsys/pkg/CFR-2011-title47-vol2/pdf/CFR-2011-title47-vol2-sec24-135.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title47-vol2/pdf/CFR-2011-title47-vol2-sec24-135.pdf"><span>47 CFR 24.135 - <span class="hlt">Frequency</span> stability.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 47 Telecommunication 2 2011-10-01 2011-10-01 false <span class="hlt">Frequency</span> stability. 24.135 Section 24.135... SERVICES Narrowband PCS § 24.135 <span class="hlt">Frequency</span> stability. (a) The <span class="hlt">frequency</span> stability of the transmitter shall be maintained within ±0.0001 percent (±1 ppm) of the center <span class="hlt">frequency</span> over a temperature <span class="hlt">variation</span>...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title47-vol2/pdf/CFR-2010-title47-vol2-sec24-135.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title47-vol2/pdf/CFR-2010-title47-vol2-sec24-135.pdf"><span>47 CFR 24.135 - <span class="hlt">Frequency</span> stability.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 47 Telecommunication 2 2010-10-01 2010-10-01 false <span class="hlt">Frequency</span> stability. 24.135 Section 24.135... SERVICES Narrowband PCS § 24.135 <span class="hlt">Frequency</span> stability. (a) The <span class="hlt">frequency</span> stability of the transmitter shall be maintained within ±0.0001 percent (±1 ppm) of the center <span class="hlt">frequency</span> over a temperature <span class="hlt">variation</span>...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title47-vol2/pdf/CFR-2013-title47-vol2-sec24-135.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title47-vol2/pdf/CFR-2013-title47-vol2-sec24-135.pdf"><span>47 CFR 24.135 - <span class="hlt">Frequency</span> stability.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 47 Telecommunication 2 2013-10-01 2013-10-01 false <span class="hlt">Frequency</span> stability. 24.135 Section 24.135... SERVICES Narrowband PCS § 24.135 <span class="hlt">Frequency</span> stability. (a) The <span class="hlt">frequency</span> stability of the transmitter shall be maintained within ±0.0001 percent (±1 ppm) of the center <span class="hlt">frequency</span> over a temperature <span class="hlt">variation</span>...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title47-vol2/pdf/CFR-2014-title47-vol2-sec24-135.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title47-vol2/pdf/CFR-2014-title47-vol2-sec24-135.pdf"><span>47 CFR 24.135 - <span class="hlt">Frequency</span> stability.</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 2 2014-10-01 2014-10-01 false <span class="hlt">Frequency</span> stability. 24.135 Section 24.135... SERVICES Narrowband PCS § 24.135 <span class="hlt">Frequency</span> stability. (a) The <span class="hlt">frequency</span> stability of the transmitter shall be maintained within ±0.0001 percent (±1 ppm) of the center <span class="hlt">frequency</span> over a temperature <span class="hlt">variation</span>...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title47-vol2/pdf/CFR-2012-title47-vol2-sec24-135.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title47-vol2/pdf/CFR-2012-title47-vol2-sec24-135.pdf"><span>47 CFR 24.135 - <span class="hlt">Frequency</span> stability.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 47 Telecommunication 2 2012-10-01 2012-10-01 false <span class="hlt">Frequency</span> stability. 24.135 Section 24.135... SERVICES Narrowband PCS § 24.135 <span class="hlt">Frequency</span> stability. (a) The <span class="hlt">frequency</span> stability of the transmitter shall be maintained within ±0.0001 percent (±1 ppm) of the center <span class="hlt">frequency</span> over a temperature <span class="hlt">variation</span>...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5783869','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5783869"><span>Wax <span class="hlt">separation</span> process</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Broadhurst, T.E.</p> <p>1980-06-03</p> <p>Particles of solid wax are <span class="hlt">separated</span> from a slurry comprising said wax particles and a hydrocarbon oil by filtering the slurry through a cloth filter medium. It has been found that using, as the filter medium, a needled-felt cloth fabricated from fibers fusible by means of an open flame and having a singed surface on which the wax is collected results in an unexpected reduction in filter cloth blinding thereby yielding up to 30% increased throughput through the filter cloth and greatly reducing the <span class="hlt">frequency</span> of washing the filter cloth. The cloth is further characterized in that it has a permeability to air in excess of about 3 cubic feet per minute per square foot of cloth surface at a differential pressure of 0.5 inches of water, a root mean square surface roughness in excess of 500 rms microinches and a fouling factor in excess of about 75%. This improved process has been found to be particularly useful for <span class="hlt">separating</span> wax particles from a dewaxed lube oil slurry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7205091','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/7205091"><span>Light beam <span class="hlt">frequency</span> comb generator</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Priatko, G.J.; Kaskey, J.A.</p> <p>1992-11-24</p> <p>A light beam <span class="hlt">frequency</span> comb generator uses an acousto-optic modulator to generate a plurality of light beams with <span class="hlt">frequencies</span> which are uniformly <span class="hlt">separated</span> and possess common noise and drift characteristics. A well collimated monochromatic input light beam is passed through this modulator to produce a set of both <span class="hlt">frequency</span> shifted and unshifted optical beams. An optical system directs one or more <span class="hlt">frequency</span> shifted beams along a path which is parallel to the path of the input light beam such that the <span class="hlt">frequency</span> shifted beams are made incident on the modulator proximate to but <span class="hlt">separated</span> from the point of incidence of the input light beam. After the beam is thus returned to and passed through the modulator repeatedly, a plurality of mutually parallel beams are generated which are <span class="hlt">frequency</span>-shifted different numbers of times and possess common noise and drift characteristics. 2 figs.</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_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" 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_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</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="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/868558','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/868558"><span>Light beam <span class="hlt">frequency</span> comb generator</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Priatko, Gordon J.; Kaskey, Jeffrey A.</p> <p>1992-01-01</p> <p>A light beam <span class="hlt">frequency</span> comb generator uses an acousto-optic modulator to generate a plurality of light beams with <span class="hlt">frequencies</span> which are uniformly <span class="hlt">separated</span> and possess common noise and drift characteristics. A well collimated monochromatic input light beam is passed through this modulator to produce a set of both <span class="hlt">frequency</span> shifted and unshifted optical beams. An optical system directs one or more <span class="hlt">frequency</span> shifted beams along a path which is parallel to the path of the input light beam such that the <span class="hlt">frequency</span> shifted beams are made incident on the modulator proximate to but <span class="hlt">separated</span> from the point of incidence of the input light beam. After the beam is thus returned to and passed through the modulator repeatedly, a plurality of mutually parallel beams are generated which are <span class="hlt">frequency</span>-shifted different numbers of times and possess common noise and drift characteristics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=contour&pg=2&id=EJ865273','ERIC'); return false;" href="http://eric.ed.gov/?q=contour&pg=2&id=EJ865273"><span>Contour Integration across Spatial <span class="hlt">Frequency</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>Persike, Malte; Olzak, Lynn A.; Meinhardt, Gunter</p> <p>2009-01-01</p> <p>Association field models of contour integration suggest that local band-pass elements are spatially grouped to global contours within limited bands of spatial <span class="hlt">frequency</span> (Field, Hayes, & Hess, 1993). While results for local orientation and spacing <span class="hlt">variation</span> render support for AF models, effects of spatial <span class="hlt">frequency</span> (SF) have rarely been addressed.…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730000463','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730000463"><span>Ferrofluid <span class="hlt">separator</span> for nonferrous scrap <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kaiser, R.; Mir, L.</p> <p>1974-01-01</p> <p>Behavior of nonmagnetic objects within <span class="hlt">separator</span> is essentially function of density, and independent of size or shape of objects. Results show close agreement between density of object and apparent density of ferrofluid required to float it. Results also demonstrate that very high <span class="hlt">separation</span> rates are achievable by ferrofluid sink-float <span class="hlt">separation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1001134','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1001134"><span>Deep Ensemble Learning for Monaural Speech <span class="hlt">Separation</span></span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>2015-02-01</p> <p>Ensemble Learning for Monaural Speech <span class="hlt">Separation</span> Xiao-Lei Zhang Department of Computer Science and Engineering The Ohio State University, Columbus...State University, Columbus, OH 43210, USA dwang@cse.ohio-state.edu Abstract – Monaural speech <span class="hlt">separation</span> is a fundamental problem in robust speech...processing. Recently, deep neural network (DNN) based speech <span class="hlt">separation</span> methods, which predict either clean speech or an ideal time-<span class="hlt">frequency</span> mask, have</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830026125','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830026125"><span><span class="hlt">Separability</span> of agricultural crops with airborne scatterometry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mehta, N. C.</p> <p>1983-01-01</p> <p>Backscattering measurements were acquired with airborne scatterometers over a site in Cass County, North Dakota on four days in the 1981 crop growing season. Data were acquired at three <span class="hlt">frequencies</span> (L-, C- and Ku-bands), two polarizations (like and cross) and ten incidence angles (5 degrees to 50 degrees in 5 degree steps). Crop <span class="hlt">separability</span> is studied in an hierarchical fashion. A two-class <span class="hlt">separability</span> measure is defined, which compares within-class to between-class variability, to determine crop <span class="hlt">separability</span>. The scatterometer channels with the best potential for crop <span class="hlt">separability</span> are determined, based on this <span class="hlt">separability</span> measure. Higher <span class="hlt">frequencies</span> are more useful for discriminating small grains, while lower <span class="hlt">frequencies</span> tend to <span class="hlt">separate</span> non-small grains better. Some crops are more <span class="hlt">separable</span> when row direction is taken into account. The effect of pixel purity is to increase the <span class="hlt">separability</span> between all crops while not changing the order of useful scatterometer channels. Crude estimates of <span class="hlt">separability</span> errors are calculated based on these analyses. These results are useful in selecting the parameters of active microwave systems in agricultural remote sensing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4090194','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4090194"><span>Feline Calicivirus Can Tolerate Gross Changes of Its Minor Capsid Protein Expression Levels Induced by Changing Translation Reinitiation <span class="hlt">Frequency</span> or Use of a <span class="hlt">Separate</span> VP2-Coding mRNA</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Meyers, Gregor</p> <p>2014-01-01</p> <p>Caliciviruses use reinitiation of translation governed by a ‘termination upstream ribosomal binding site’ (TURBS) for expression of their minor capsid protein VP2. Mutation analysis allowed to identify sequences surrounding the translational start/stop site of the feline calicivirus (FCV) that fine tune reinitiation <span class="hlt">frequency</span>. A selection of these changes was introduced into the infectious FCV cDNA clone to check the influence of altered VP2 levels on virus replication. In addition, full length constructs were established that displayed a conformation, in which VP2 expression occurred under control of a duplicated subgenomic promoter. Viable viruses recovered from such constructs revealed a rather broad range of VP2 expression levels but comparable growth kinetics showing that caliciviruses can tolerate gross changes of the VP2 expression level. PMID:25007260</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18450479','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18450479"><span><span class="hlt">Variational</span> filtering.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Friston, K J</p> <p>2008-07-01</p> <p>This note presents a simple Bayesian filtering scheme, using <span class="hlt">variational</span> calculus, for inference on the hidden states of dynamic systems. <span class="hlt">Variational</span> filtering is a stochastic scheme that propagates particles over a changing <span class="hlt">variational</span> energy landscape, such that their sample density approximates the conditional density of hidden and states and inputs. The key innovation, on which <span class="hlt">variational</span> filtering rests, is a formulation in generalised coordinates of motion. This renders the scheme much simpler and more versatile than existing approaches, such as those based on particle filtering. We demonstrate <span class="hlt">variational</span> filtering using simulated and real data from hemodynamic systems studied in neuroimaging and provide comparative evaluations using particle filtering and the fixed-form homologue of <span class="hlt">variational</span> filtering, namely dynamic expectation maximisation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://kidshealth.org/en/parents/sep-anxiety.html','NIH-MEDLINEPLUS'); return false;" href="https://kidshealth.org/en/parents/sep-anxiety.html"><span><span class="hlt">Separation</span> Anxiety (For Parents)</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... Old Feeding Your 1- to 2-Year-Old <span class="hlt">Separation</span> Anxiety KidsHealth > For Parents > <span class="hlt">Separation</span> Anxiety Print A ... help both of you get through it. About <span class="hlt">Separation</span> Anxiety Babies adapt pretty well to other caregivers. ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27805695','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27805695"><span>Clustered <span class="hlt">frequency</span> comb.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Matsko, Andrey B; Savchenkov, Anatoliy A; Huang, Shu-Wei; Maleki, Lute</p> <p>2016-11-01</p> <p>We show theoretically that it is feasible to generate a spectrally broad Kerr <span class="hlt">frequency</span> comb consisting of several spectral clusters phase matched due to interplay among second- and higher-order group velocity dispersion contributions. We validate the theoretical analysis experimentally by driving a magnesium fluoride resonator, characterized with 110 GHz free spectral range, with a continuous wave light at 1.55 μm and observing two comb clusters <span class="hlt">separated</span> by nearly two-thirds of an octave.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA03245&hterms=animation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Danimation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA03245&hterms=animation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Danimation"><span>Spacecraft -- Capsule <span class="hlt">Separation</span> (Animation)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2005-01-01</p> <p>[figure removed for brevity, see original site] Click on the image for Spacecraft -- Capsule <span class="hlt">Separation</span> animation <p/> This animation shows the return capsule <span class="hlt">separating</span> from the Stardust spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT.......153A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT.......153A"><span>Numerical modeling of active <span class="hlt">separation</span> control by synthetic jets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aram, Shawn</p> <p></p> <p> oriented slot is a pair of strong counter-rotating streamwise vortices and these are missing in the spanwise oriented slot configuration. A variety of flow statistics are computed that indicate that despite the smaller overall blockage represented by the streamwise oriented slot, it is more effective in increasing the momentum of the boundary layer and therefore is expected to be more effective in <span class="hlt">separation</span> control. For further investigation, the effect of slot orientation at different operational conditions (jet velocity and <span class="hlt">frequency</span>) on a <span class="hlt">separated</span> flow over a wall-mounted hump is examined in the third part of this work. Comparison of various instantaneous integral quantities, time average aerodynamic parameters and <span class="hlt">separation</span> bubble size between two slot configurations shows that the streamwise oriented slot provides better performance in all jet velocities and most forcing <span class="hlt">frequencies</span> of the range of study. In the fourth and final part of the study, a canonical <span class="hlt">separated</span> flow configuration is used to explore the rich flow physics and nonlinear dynamics of <span class="hlt">separated</span> flows in a systematic manner and to establish a flow-physics based understanding of effective forcing schemes. This configuration consists of a three dimensional 9.5% thick flat plate with an elliptical leading edge and a blunt trailing edge with <span class="hlt">separation</span> induced through the application of blowing and suction on the top boundary of the computational domain. The key aspect of this approach is that the <span class="hlt">separation</span> bubble can be located in any position along the suction side of the plate with desired size along with <span class="hlt">separate</span> control on the Reynolds number which is not possible by <span class="hlt">variation</span> of angle of attack and/or free-stream velocity for an airfoil. This study shows that even this simple canonical <span class="hlt">separated</span> flow is dominated by nonlinear interactions between the shear layer, <span class="hlt">separation</span> bubble, and wake instabilities in a manner that is representative of more complex airfoil <span class="hlt">separation</span>. The simple boundary</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/917521','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/917521"><span>High-<span class="hlt">Frequency</span> and Very-high-<span class="hlt">Frequency</span> (HF&VHF) above-groundelectromagnetic impedance measurements</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Frangos, William; Becker, Alex; Lee, K.H.</p> <p>2002-09-20</p> <p>We have field-tested an apparatus for measuring the electromagnetic impedance above the ground at a plurality of <span class="hlt">frequencies</span> in the 0.3 - 30 MHz range. This window in the <span class="hlt">frequency</span> spectrum, which lies between <span class="hlt">frequencies</span> used for GPR and those used for conventional loop-loop EM soundings, has not been used because of difficulties in fielding equipment for making absolute and accurate measurements. Model and physical parameter studies however confirm that data in this <span class="hlt">frequency</span> band can be used to construct high-resolution maps of electrical conductivity and permittivity of near-surface material. Our equipment was assembled using commercial electric and magnetic antennas. The magnetic loop source is excited by a conventional signal generator - power amplifier assembly. Signal detection is accomplished using RF lock-in amplifiers. All system elements are appropriately isolated by optic - fiber links. We estimate a measurement accuracy of about {+-} 10% for an 8-m <span class="hlt">separation</span> between source and detector. Field tests were done at the University of California Richmond Field Station where the near surface electrical structure is well known. The experimental data at this site are mainly a function of electrical conductivity. In this context, we have obtained good agreement with the known local <span class="hlt">variations</span> in resistivity both with depth and with position along a 35-m traverse. Additional tests in more resistive regimes where dielectric permittivity is not negligible yield spectral data compatible with the less well known near-surface electrical properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MS%26E..163a2036B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MS%26E..163a2036B"><span>Single-phase <span class="hlt">frequency</span> converter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baciu, I.; Cunţan, C. D.</p> <p>2017-01-01</p> <p>The paper presents a continuous voltage inverter - AC (12V / 230V) made with IGBT and two-stage voltage transformer. The sequence control transistors is achieved using a ring counter whose clock signal is obtained with a monostable circuit LM 555. The <span class="hlt">frequency</span> of the clock signal can be adjustment with a potentiometer that modifies the charging current of the capacitor which causes constant monostable circuit time. Command sequence consists of 8 intervals of which 6 are assigned to command four transistors and two for the period break at the beginning and end of the sequence control. To obtain an alternation consisting of two different voltage level, two transistors will be comanded, connected to different windings of the transformer and the one connected to the winding providing lower voltage must be comanded twice. The output of the numerator goes through an inverter type MOS and a current amplifier with bipolar transistor.To achieve galvanic <span class="hlt">separation</span>, an optocoupler will be used for each IGBT transistor, while protection is achieved with resistance and diode circuit. At the end there is connected an LC filter for smoothing voltage <span class="hlt">variations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6744421','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6744421"><span>Hydrocyclone <span class="hlt">separation</span> system</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Worrell, J.R.; Wakley, W.D.; Young, G.A.</p> <p>1990-05-22</p> <p>This patent describes a hydrocyclone <span class="hlt">separation</span> system for <span class="hlt">separating</span> a fluid mixture into at least two components having differing densities. It comprises: a first hydrocyclone <span class="hlt">separator</span> and a second hydrocyclone <span class="hlt">separator</span> contained within an elongated protective conduit and each being substantially parallel to a longitudinal axis of the conduit, each hydrocyclone <span class="hlt">separator</span> having a tangential fluid inlet, an overflow fluid outlet and an underflow fluid outlet; and the first hydrocyclone <span class="hlt">separator</span> and the second hydrocyclone <span class="hlt">separator</span> being oppositely disposed with respect to each other with the underflow fluid outlet of the first hydrocyclone <span class="hlt">separator</span> being spaced immediately adjacent to the tangential fluid inlet of the second hydrocyclone <span class="hlt">separator</span> and the overflow fluid outlet of the first hydrocyclone <span class="hlt">separator</span> being spaced immediately adjacent the underflow fluid outlet of the second hydrocyclone <span class="hlt">separator</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/1179219','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/1179219"><span>Binaural beats at high <span class="hlt">frequencies</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McFadden, D; Pasanen, E G</p> <p>1975-10-24</p> <p>Binaural beats have long been believed to be audible only at low <span class="hlt">frequencies</span>, but an interaction reminiscent of a binaural beat can sometimes be heard when different two-tone complexes of high <span class="hlt">frequency</span> are presented to the two ears. The primary requirement is that the <span class="hlt">frequency</span> <span class="hlt">separation</span> in the complex at one ear be slightly different from that in the other--that is, that there be a small interaural difference in the envelope periodicities. This finding is in accord with other recent demonstrations that the auditory system is not deaf to interaural time differences at high <span class="hlt">frequencies</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JaJAP..55aAF04L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JaJAP..55aAF04L"><span>Tailoring surface properties of polyethylene <span class="hlt">separator</span> by low pressure 13.56 MHz RF oxygen plasma glow discharge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Chun; Liang, Chia-Han; Huang, Chun</p> <p>2016-01-01</p> <p>Low-pressure plasma surface modification in a radio-<span class="hlt">frequency</span> capacitively coupled glow discharge of oxygen gas was carried out to induce polar functional groups onto polyethylene membrane <span class="hlt">separator</span> surfaces to enhance its hydrophilicity. The surface changes in surface free energy were monitored by static contact angle measurement. A significant increase in the surface energy of polyethylene membrane <span class="hlt">separators</span> caused by the oxygen gas plasma modifications was observed. The static water contact angle of the plasma-modified membrane <span class="hlt">separator</span> significantly decreased with the increase in treatment duration and plasma power. An obvious increase in the surface energy of the membrane <span class="hlt">separators</span> owing to the oxidative effect of oxygen-gas-plasma modifications was also observed. Optical emission spectroscopy was carried out to analyze the chemical species generated by oxygen gas plasma surface modification. The <span class="hlt">variations</span> in the surface morphology and chemical structure of the <span class="hlt">separators</span> were confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS). XPS showed significantly higher surface concentrations of oxygen functional groups in the oxygen-gas-plasma-modified polymeric <span class="hlt">separator</span> surfaces than in the unmodified polymeric <span class="hlt">separator</span> surface. The experimental results show the important role of chemical species in the interaction between oxygen gas plasmas and the <span class="hlt">separator</span> surface, which can be controlled by surface modification to tailor the hydrophilicity of the <span class="hlt">separator</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1233799','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1233799"><span>Magnetic <span class="hlt">Separation</span> Dynamics of Colloidal Magnetic Nanoparticles</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kaur, M.; Huijin Zhang,; You Qiang,</p> <p>2013-01-01</p> <p>Surface functionalized magnetic nanoparticles (MNPs) are appealing candidates for analytical <span class="hlt">separation</span> of heavy metal ions from waste water and <span class="hlt">separation</span> of actinides from spent nuclear fuel. This work studies the <span class="hlt">separation</span> dynamics and investigates the appropriate magnetic-field gradients. A dynamic study of colloidal MNPs was performed for steady-state flow. Measurements were conducted to record the <span class="hlt">separation</span> time of particles as a function of magnetic field gradient. The drag and magnetic forces play a significant role on the <span class="hlt">separation</span> time. A drop in saturation magnetization and <span class="hlt">variation</span> of particle size occurs after surface functionalization of the MNPs; these are the primary factors that affect the <span class="hlt">separation</span> time and velocity of the MNPs. The experimental results are correlated to a theoretical one-dimensional model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EEEV...14..715K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EEEV...14..715K"><span>Analysis of <span class="hlt">frequency</span> shifting in seismic signals using Gabor-Wigner transform</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kumar, Roshan; Sumathi, P.; Kumar, Ashok</p> <p>2015-12-01</p> <p>A hybrid time-<span class="hlt">frequency</span> method known as Gabor-Wigner transform (GWT) is introduced in this paper for examining the time-<span class="hlt">frequency</span> 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 <span class="hlt">separately</span> on synthetic and recorded earthquake data to identify <span class="hlt">frequency</span> 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 (<span class="hlt">frequency</span> interference), GT and WVD are judiciously combined and the resultant GWT used to identify <span class="hlt">frequency</span> 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 <span class="hlt">variations</span> in <span class="hlt">frequency</span>, good time-<span class="hlt">frequency</span> resolution, and localized response. Presented results confirm the efficacy of GWT when compared with GT and WVD used <span class="hlt">separately</span>. 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10573865','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10573865"><span><span class="hlt">Frequency</span> discrimination of brief tonal steps as a function of <span class="hlt">frequency</span> in the lesser bulldog bat.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roverud, R C</p> <p>1999-09-01</p> <p>In a two-alternative, forced-choice task lesser bulldog bats were trained to distinguish between a pure tone pulse and a pulse composed of a series of brief tonal steps oscillating between two different <span class="hlt">frequencies</span>. The tone-step pulse gradually approximates the pure tone pulse as the <span class="hlt">frequency</span> difference between the steps becomes progressively smaller. <span class="hlt">Frequency</span> difference limens for the brief tonal <span class="hlt">frequency</span> steps were determined for a broad range of ultrasonic <span class="hlt">frequencies</span>. The <span class="hlt">variation</span> in tone-step difference limens with <span class="hlt">frequency</span> appears to be correlated to the <span class="hlt">frequency</span> structure of the bat's short-constant-<span class="hlt">frequency/frequency</span>-modulated echolocation sound. There was a marked decline in the value of the relative <span class="hlt">frequency</span> difference limens (Weber ratio) over a fairly narrow range of <span class="hlt">frequencies</span> above the constant <span class="hlt">frequency</span> and a sharp increase in threshold above this range. The relative thresholds for <span class="hlt">frequency</span> discrimination were small and uniform over the <span class="hlt">frequency</span> range of the <span class="hlt">frequency</span>-modulated sweep and increased for <span class="hlt">frequencies</span> below the <span class="hlt">frequency</span>-modulated sweep. Thus, the most accurate <span class="hlt">frequency</span>-discrimination abilities occur over a narrow <span class="hlt">frequency</span> range around the <span class="hlt">frequency</span> of the constant-<span class="hlt">frequency</span> component of returning echoes. <span class="hlt">Frequency</span> discrimination over the range of <span class="hlt">frequencies</span> of the <span class="hlt">frequency</span>-modulated component is relatively good.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23518735','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23518735"><span>Interferometric homogeneity test using adaptive <span class="hlt">frequency</span> comb illumination.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mantel, Klaus; Schwider, Johannes</p> <p>2013-03-20</p> <p>The homogeneity test of glass plates in a Fizeau interferometer requires the measurement of the glass sample in reflected as well as in transmitted light. For the measurement in transmitted light, the sample has to be inserted into the ray path of a Fizeau or Twyman-Green interferometer, which leads to a nested cavity setup. To <span class="hlt">separate</span> the interference signals from the different cavities, we illuminate a Fizeau interferometer with an adaptive <span class="hlt">frequency</span> comb. In this way, rigid glass plates can be measured, and linear <span class="hlt">variations</span> in the homogeneity can also be detected. The adaptive <span class="hlt">frequency</span> comb is provided by a variable Fabry-Perot filter under broadband illumination from a superluminescence diode. Compared to approaches using a two-beam interferometer as a filter for the broadband light source, the visibility of the fringe system is considerably higher.</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_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" 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_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</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="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790011946','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790011946"><span>Theory of low <span class="hlt">frequency</span> noise transmission through turbines</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Matta, R. K.; Mani, R.</p> <p>1979-01-01</p> <p>Improvements of the existing theory of low <span class="hlt">frequency</span> noise transmission through turbines and development of a working prediction tool are described. The existing actuator-disk model and a new finite-chord model were utilized in an analytical study. The interactive effect of adjacent blade rows, higher order spinning modes, blade-passage shocks, and duct area <span class="hlt">variations</span> were considered <span class="hlt">separately</span>. The improved theory was validated using the data acquired in an earlier NASA program. Computer programs incorporating the improved theory were produced for transmission loss prediction purposes. The programs were exercised parametrically and charts constructed to define approximately the low <span class="hlt">frequency</span> noise transfer through turbines. The loss through the exhaust nozzle and flow(s) was also considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1980ucla.rept.....F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1980ucla.rept.....F"><span>Vapors-liquid phase <span class="hlt">separator</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frederking, T. H. K.; Brown, G. S.; Chuang, C.; Kamioka, Y.; Kim, Y. I.; Lee, J. M.; Yuan, S. W. K.</p> <p>1980-10-01</p> <p>The use of porous plugs, mostly with in the form of passive devices with constant area were considered as vapor-liquid phase <span class="hlt">separators</span> for helium 2 storage vessels under reduced gravity. The incorporation of components with variable cross sectional area as a method of flow rate modification was also investigated. A particular device which uses a shutter-type system for area <span class="hlt">variation</span> was designed and constructed. This system successfully permitted flor rate changes of up to plus or minus 60% from its mean value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1248896','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1248896"><span>Magnetic <span class="hlt">separation</span> of algae</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nath, Pulak; Twary, Scott N.</p> <p>2016-04-26</p> <p>Described herein are methods and systems for harvesting, collecting, <span class="hlt">separating</span> and/or dewatering algae using iron based salts combined with a magnetic field gradient to <span class="hlt">separate</span> algae from an aqueous solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://medlineplus.gov/ency/article/001542.htm','NIH-MEDLINEPLUS'); return false;" href="https://medlineplus.gov/ency/article/001542.htm"><span><span class="hlt">Separation</span> anxiety in children</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... this page: //medlineplus.gov/ency/article/001542.htm <span class="hlt">Separation</span> anxiety in children To use the sharing features on this page, please enable JavaScript. <span class="hlt">Separation</span> anxiety in children is a developmental stage in ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19690000481','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19690000481"><span>Ionene membrane battery <span class="hlt">separator</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moacanin, J.; Tom, H. Y.</p> <p>1969-01-01</p> <p>Ionic transport characteristics of ionenes, insoluble membranes from soluble polyelectrolyte compositions, are studied for possible application in a battery <span class="hlt">separator</span>. Effectiveness of the thin film of <span class="hlt">separator</span> membrane essentially determines battery lifetime.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940012260','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940012260"><span>Comparison of JPL-AIRSAR and DLR E-SAR images from the MAC Europe 1991 campaign over testsite Oberpfaffenhofen: <span class="hlt">Frequency</span> and polarization dependent backscatter <span class="hlt">variations</span> from agricultural fields</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmullius, C.; Nithack, J.</p> <p>1992-01-01</p> <p>On July 12, the MAC Europe '91 (Multi-Sensor Airborne Campaign) took place over test site Oberpfaffenhofen. The DLR Institute of Radio-<span class="hlt">Frequency</span> Technology participated with its C-VV, X-VV, and X-HH Experimental Synthetic Aperture Radar (E-SAR). The high resolution E-SAR images with a pixel size between 1 and 2 m and the polarimetric AIRSAR images were analyzed. Using both sensors in combination is a unique opportunity to evaluate SAR images in a <span class="hlt">frequency</span> range from P- to X-band and to investigate polarimetric information.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7156946','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/7156946"><span><span class="hlt">Frequency</span> regulator for synchronous generators</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Karlicek, R.F.</p> <p>1982-08-10</p> <p>The present invention is directed to a novel <span class="hlt">frequency</span> regulator which controls a generator output <span class="hlt">frequency</span> for <span class="hlt">variations</span> in both the input power to the generator and the power supplied to an uncontrolled external load. The present invention further includes over current and current balance protection devices which are relatively inexpensive to manufacture, which may be encapsulated to provide protection from the operating environment and which respond more quickly than previously known electromechanical devices. 11 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/864305','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/864305"><span><span class="hlt">Frequency</span> regulator for synchronous generators</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Karlicek, Robert F.</p> <p>1982-01-01</p> <p>The present invention is directed to a novel <span class="hlt">frequency</span> regulator which controls a generator output <span class="hlt">frequency</span> for <span class="hlt">variations</span> in both the input power to the generator and the power supplied to an uncontrolled external load. The present invention further includes over current and current balance protection devices which are relatively inexpensive to manufacture, which may be encapsulated to provide protection from the operating environment and which respond more quickly than previously known electromechanical devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20718866','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20718866"><span>New limit on the present temporal <span class="hlt">variation</span> of the fine structure constant</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Peik, E.; Lipphardt, B.; Schnatz, H.; Schneider, T.; Tamm, Chr.; Karshenboim, S.G.</p> <p>2005-05-05</p> <p>A comparison of different atomic <span class="hlt">frequency</span> standards over time can be used to perform a measurement of the present value of the temporal derivative of the fine structure constant {alpha} in a model-independent way without assumptions on constancy or variability of other parameters. We have measured an optical transition <span class="hlt">frequency</span> at 688 THz in Yb+ with a cesium atomic clock at two times <span class="hlt">separated</span> by 2.8 years and find that a <span class="hlt">variation</span> of this <span class="hlt">frequency</span> can be excluded within a 1{sigma} relative uncertainty of 4.4{center_dot}10-15 yr-1. Combined with recently published values for the constancy of other transition <span class="hlt">frequencies</span> this measurement provides a limit on the present variability of {alpha} at the level of 2.0{center_dot}10-15 yr-1. Constraints are also derived for the drift rates of other fundamental constants like the electron/proton mass ratio and the proton g-factor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22483216','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22483216"><span>Chaotic attractors with <span class="hlt">separated</span> scrolls</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bouallegue, Kais</p> <p>2015-07-15</p> <p>This paper proposes a new behavior of chaotic attractors with <span class="hlt">separated</span> scrolls while combining Julia's process with Chua's attractor and Lorenz's attractor. The main motivation of this work is the ability to generate a set of <span class="hlt">separated</span> scrolls with different behaviors, which in turn allows us to choose one or many scrolls combined with modulation (amplitude and <span class="hlt">frequency</span>) for secure communication or synchronization. This set seems a new class of hyperchaos because each element of this set looks like a simple chaotic attractor with one positive Lyapunov exponent, so the cardinal of this set is greater than one. This new approach could be used to generate more general higher-dimensional hyperchaotic attractor for more potential application. Numerical simulations are given to show the effectiveness of the proposed theoretical results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/880338','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/880338"><span>Meniscus Membranes For <span class="hlt">Separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Dye, Robert C.; Jorgensen, Betty; Pesiri, David R.</p> <p>2005-09-20</p> <p>Gas <span class="hlt">separation</span> membranes, especially meniscus-shaped membranes for gas <span class="hlt">separations</span> are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas <span class="hlt">separation</span> is provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/935568','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/935568"><span>Meniscus membranes for <span class="hlt">separations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Dye, Robert C.; Jorgensen, Betty; Pesiri, David R.</p> <p>2004-01-27</p> <p>Gas <span class="hlt">separation</span> membranes, especially meniscus-shaped membranes for gas <span class="hlt">separations</span> are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas <span class="hlt">separation</span> is provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860000231&hterms=liquid+liquid+separation+methods&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dliquid%2Bliquid%2Bseparation%2Bmethods','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860000231&hterms=liquid+liquid+separation+methods&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dliquid%2Bliquid%2Bseparation%2Bmethods"><span><span class="hlt">Separation</span> in Binary Alloys</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Frazier, D. O.; Facemire, B. R.; Kaukler, W. F.; Witherow, W. K.; Fanning, U.</p> <p>1986-01-01</p> <p>Studies of monotectic alloys and alloy analogs reviewed. Report surveys research on liquid/liquid and solid/liquid <span class="hlt">separation</span> in binary monotectic alloys. Emphasizes <span class="hlt">separation</span> processes in low gravity, such as in outer space or in free fall in drop towers. Advances in methods of controlling <span class="hlt">separation</span> in experiments highlighted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009fsm..conf.....M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009fsm..conf.....M"><span><span class="hlt">Frequency</span> Standards and Metrology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maleki, Lute</p> <p>2009-04-01</p> <p>Preface / Lute Maleki -- Symposium history / Jacques Vanier -- Symposium photos -- pt. I. Fundamental physics. <span class="hlt">Variation</span> of fundamental constants from the big bang to atomic clocks: theory and observations (Invited) / V. V. Flambaum and J. C. Berengut. Alpha-dot or not: comparison of two single atom optical clocks (Invited) / T. Rosenband ... [et al.]. <span class="hlt">Variation</span> of the fine-structure constant and laser cooling of atomic dysprosium (Invited) / N. A. Leefer ... [et al.]. Measurement of short range forces using cold atoms (Invited) / F. Pereira Dos Santos ... [et al.]. Atom interferometry experiments in fundamental physics (Invited) / S. W. Chiow ... [et al.]. Space science applications of <span class="hlt">frequency</span> standards and metrology (Invited) / M. Tinto -- pt. II. <span class="hlt">Frequency</span> & metrology. Quantum metrology with lattice-confined ultracold Sr atoms (Invited) / A. D. Ludlow ... [et al.]. LNE-SYRTE clock ensemble: new [symbol]Rb hyperfine <span class="hlt">frequency</span> measurement - spectroscopy of [symbol]Hg optical clock transition (Invited) / M. Petersen ... [et al.]. Precise measurements of S-wave scattering phase shifts with a juggling atomic clock (Invited) / S. Gensemer ... [et al.]. Absolute <span class="hlt">frequency</span> measurement of the [symbol] clock transition (Invited) / M. Chwalla ... [et al.]. The semiclassical stochastic-field/atom interaction problem (Invited) / J. Camparo. Phase and <span class="hlt">frequency</span> noise metrology (Invited) / E. Rubiola ... [et al.]. Optical spectroscopy of atomic hydrogen for an improved determination of the Rydberg constant / J. L. Flowers ... [et al.] -- pt. III. Clock applications in space. Recent progress on the ACES mission (Invited) / L. Cacciapuoti and C. Salomon. The SAGAS mission (Invited) / P. Wolf. Small mercury microwave ion clock for navigation and radioScience (Invited) / J. D. Prestage ... [et al.]. Astro-comb: revolutionizing precision spectroscopy in astrophysics (Invited) / C. E. Kramer ... [et al.]. High <span class="hlt">frequency</span> very long baseline interferometry: <span class="hlt">frequency</span> standards and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1005582','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1005582"><span>Self-assembly of amorphous biophotonic nanostructures by phase <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dufresne, Eric R.; Noh, Heeso; Saranathan, Vinodkumar; Mochrie, Simon G.J.; Cao, Hui; Prum, Richard O.</p> <p>2009-04-23</p> <p>Some of the most vivid colors in the animal kingdom are created not by pigments, but by wavelength-selective scattering of light from nanostructures. Here we investigate quasi-ordered nanostructures of avian feather barbs which produce vivid non-iridescent colors. These {beta}-keratin and air nanostructures are found in two basic morphologies: tortuous channels and amorphous packings of spheres. Each class of nanostructure is isotropic and has a pronounced characteristic length scale of <span class="hlt">variation</span> in composition. These local structural correlations lead to strong backscattering over a narrow range of optical <span class="hlt">frequencies</span> and little <span class="hlt">variation</span> with angle of incidence. Such optical properties play important roles in social and sexual communication. To be effective, birds need to precisely control the development of these nanoscale structures, yet little is known about how they grow. We hypothesize that multiple lineages of birds have convergently evolved to exploit phase <span class="hlt">separation</span> and kinetic arrest to self-assemble spongy color-producing nanostructures in feather barbs. Observed avian nanostructures are strikingly similar to those self-assembled during the phase <span class="hlt">separation</span> of fluid mixtures; the channel and sphere morphologies are characteristic of phase <span class="hlt">separation</span> by spinodal decomposition and nucleation and growth, respectively. These unstable structures are locked-in by the kinetic arrest of the {beta}-keratin matrix, likely through the entanglement or cross-linking of supermolecular {beta}-keratin fibers. Using the power of self-assembly, birds can robustly realize a diverse range of nanoscopic morphologies with relatively small physical and chemical changes during feather development.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/776571','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/776571"><span>Beam-beam simulations for <span class="hlt">separated</span> beams</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Furman, Miguel A.</p> <p>2000-04-10</p> <p>We present beam-beam simulation results from a strong-strong gaussian code for <span class="hlt">separated</span> beams for the LHC and RHIC. The <span class="hlt">frequency</span> spectrum produced by the beam-beam collisions is readily obtained and offers a good opportunity for experimental comparisons. Although our results for the emittance blowup are preliminary, we conclude that, for nominal parameter values, there is no significant difference between <span class="hlt">separated</span> beams and center-on-center collisions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22521678','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22521678"><span><span class="hlt">FREQUENCY</span>-DEPENDENT DISPERSION MEASURES AND IMPLICATIONS FOR PULSAR TIMING</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cordes, J. M.; Shannon, R. M.; Stinebring, D. R. E-mail: ryan.shannon@csiro.au</p> <p>2016-01-20</p> <p>The dispersion measure (DM), the column density of free electrons to a pulsar, is shown to be <span class="hlt">frequency</span> dependent because of multipath scattering from small-scale electron-density fluctuations. DMs vary between propagation paths whose transverse extent varies strongly with <span class="hlt">frequency</span>, yielding arrival times that deviate from the high-<span class="hlt">frequency</span> scaling expected for a cold, uniform, unmagnetized plasma (1/<span class="hlt">frequency</span>{sup 2}). Scaling laws for thin phase screens are verified with simulations; extended media are also analyzed. The rms DM difference across an octave band near 1.5 GHz is ∼ 4 × 10{sup −5} pc cm{sup −3} for pulsars at ∼1 kpc distance. The corresponding arrival-time <span class="hlt">variations</span> are a few to hundreds of nanoseconds for DM ≲ 30 pc cm{sup −3} but increase rapidly to microseconds or more for larger DMs and wider <span class="hlt">frequency</span> ranges. Chromatic DMs introduce correlated noise into timing residuals with a power spectrum of “low pass” form. The correlation time is roughly the geometric mean of the refraction times for the highest and lowest radio <span class="hlt">frequencies</span> used, ranging from days to years, depending on the pulsar. We discuss implications for methodologies that use large <span class="hlt">frequency</span> <span class="hlt">separations</span> or wide bandwidth receivers for timing measurements. Chromatic DMs are partially mitigable by including an additional chromatic term in arrival time models. Without mitigation, an additional term in the noise model for pulsar timing is implied. In combination with measurement errors from radiometer noise, an arbitrarily large increase in total <span class="hlt">frequency</span> range (or bandwidth) will yield diminishing benefits and may be detrimental to overall timing precision.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...817...16C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...817...16C"><span><span class="hlt">Frequency</span>-dependent Dispersion Measures and Implications for Pulsar Timing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cordes, J. M.; Shannon, R. M.; Stinebring, D. R.</p> <p>2016-01-01</p> <p>The dispersion measure (DM), the column density of free electrons to a pulsar, is shown to be <span class="hlt">frequency</span> dependent because of multipath scattering from small-scale electron-density fluctuations. DMs vary between propagation paths whose transverse extent varies strongly with <span class="hlt">frequency</span>, yielding arrival times that deviate from the high-<span class="hlt">frequency</span> scaling expected for a cold, uniform, unmagnetized plasma (1/<span class="hlt">frequency</span>2). Scaling laws for thin phase screens are verified with simulations; extended media are also analyzed. The rms DM difference across an octave band near 1.5 GHz is ˜ 4 × 10-5 pc cm-3 for pulsars at ˜1 kpc distance. The corresponding arrival-time <span class="hlt">variations</span> are a few to hundreds of nanoseconds for DM ≲ 30 pc cm-3 but increase rapidly to microseconds or more for larger DMs and wider <span class="hlt">frequency</span> ranges. Chromatic DMs introduce correlated noise into timing residuals with a power spectrum of “low pass” form. The correlation time is roughly the geometric mean of the refraction times for the highest and lowest radio <span class="hlt">frequencies</span> used, ranging from days to years, depending on the pulsar. We discuss implications for methodologies that use large <span class="hlt">frequency</span> <span class="hlt">separations</span> or wide bandwidth receivers for timing measurements. Chromatic DMs are partially mitigable by including an additional chromatic term in arrival time models. Without mitigation, an additional term in the noise model for pulsar timing is implied. In combination with measurement errors from radiometer noise, an arbitrarily large increase in total <span class="hlt">frequency</span> range (or bandwidth) will yield diminishing benefits and may be detrimental to overall timing precision.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1187931','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1187931"><span>Safety shutdown <span class="hlt">separators</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Carlson, Steven Allen; Anakor, Ifenna Kingsley; Farrell, Greg Robert</p> <p>2015-06-30</p> <p>The present invention pertains to electrochemical cells which comprise (a) an anode; (b) a cathode; (c) a solid porous <span class="hlt">separator</span>, such as a polyolefin, xerogel, or inorganic oxide <span class="hlt">separator</span>; and (d) a nonaqueous electrolyte, wherein the <span class="hlt">separator</span> comprises a porous membrane having a microporous coating comprising polymer particles which have not coalesced to form a continuous film. This microporous coating on the <span class="hlt">separator</span> acts as a safety shutdown layer that rapidly increases the internal resistivity and shuts the cell down upon heating to an elevated temperature, such as 110.degree. C. Also provided are methods for increasing the safety of an electrochemical cell by utilizing such <span class="hlt">separators</span> with a safety shutdown layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/862972','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/862972"><span>Method for isotope <span class="hlt">separation</span> by photodeflection</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Bernhardt, Anthony F.</p> <p>1977-01-01</p> <p>In the method of <span class="hlt">separating</span> isotopes wherein a desired isotope species is selectively deflected out of a beam of mixed isotopes by irradiating the beam with a directed beam of light of narrowly defined <span class="hlt">frequency</span> which is selectively absorbed by the desired species, the improvement comprising irradiating the deflected beam with light from other light sources whose <span class="hlt">frequencies</span> are selected to cause the depopulation of any metastable excited states.</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_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" 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_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></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_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JMiMi..27a5031L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JMiMi..27a5031L"><span>Acoustofluidic bacteria <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Sixing; Ma, Fen; Bachman, Hunter; Cameron, Craig E.; Zeng, Xiangqun; Huang, Tony Jun</p> <p>2017-01-01</p> <p>Bacterial <span class="hlt">separation</span> from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial <span class="hlt">separation</span> from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to <span class="hlt">separate</span> Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli <span class="hlt">separated</span> from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the <span class="hlt">separated</span> E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial <span class="hlt">separation</span> platform has advantages such as label-free <span class="hlt">separation</span>, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986mico....2...23P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986mico....2...23P"><span>Broadband <span class="hlt">frequency</span> selective surface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Palma, D. A.; Wong, W. C.</p> <p></p> <p>A method for designing broadband dichroic surfaces is described. A tripole and a Jerusalem cross are evaluated as candidate resonant elements. The effects of dielectric substrates on resonant <span class="hlt">frequency</span> and bandwidth are investigated. The theoretical and measured <span class="hlt">frequency</span> responses of tripoles and Jerusalem crosses are presented. It is observed that the metallic area of the tripole within a given period increases the bandwidth, the maximum theoretical bandwidth of the tripole dichroic sheet being about 50 percent; for a Jerusalem cross, increasing the metallic area of the two perpendicular strips and increasing the end cap capacitative loading increases the bandwidth to a theoretical maximum about 60 percent. Multilayered dichroic panels capable of producing a 4:1 stopband and 1.4:1 band <span class="hlt">separation</span> have been designed for circular polarization and angles of incidence up to 40 degrees.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70180688','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70180688"><span>Genetic <span class="hlt">variation</span> in steelhead of Oregon and northern California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Reisenbichler, R.R.; McIntyre, J.D.; Solazzi, M.F.; Landino, S.W</p> <p>1992-01-01</p> <p>Steelhead Oncorhynchus mykiss from various sites between the Columbia River and the Mad River, California, were genetically characterized at 10 protein-coding loci or pairs of loci by starch gel electrophoresis. Fish from coastal streams differed from fish east of the Cascade Mountains and from fish of the Willamette River (a tributary of the Columbia River, west of the Cascade Mountains). Coastal steelhead from the northern part of the study area differed from those in the southern part. Genetic differentiation within and among drainages was not statistically significant; however, gene diversity analysis and the life history of steelhead suggested that fish from different drainages should be considered as <span class="hlt">separate</span> populations. Genetic <span class="hlt">variation</span> among fish in <span class="hlt">separate</span> drainages was similar to that reported in northwestern Washington and less than that reported in British Columbia. Allele <span class="hlt">frequencies</span> varied significantly among year-classes. Genetic <span class="hlt">variation</span> within samples accounted for 98.3% of the total genetic <span class="hlt">variation</span> observed in this study. Most hatchery populations differed from wild populations, suggesting that conservation of genetic diversity among and within wild populations could be facilitated by altering hatchery programs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9497E..0CJ','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9497E..0CJ"><span>Transform domain steganography with blind source <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jouny, Ismail</p> <p>2015-05-01</p> <p>This paper applies blind source <span class="hlt">separation</span> or independent component analysis for images that may contain mixtures of text, audio, or other images for steganography purposes. The paper focuses on <span class="hlt">separating</span> mixtures in the transform domain such as Fourier domain or the Wavelet domain. The study addresses the effectiveness of steganography when using linear mixtures of multimedia components and the ability of standard blind sources <span class="hlt">separation</span> techniques to discern hidden multimedia messages. Mixing in the space, <span class="hlt">frequency</span>, and wavelet (scale) domains is compared. Effectiveness is measured using mean square error rate between original and recovered images.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/788520','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/788520"><span>Bayesian <span class="hlt">Separation</span> of Lamb Wave Signatures</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kercel, SW</p> <p>2001-07-19</p> <p>A persistent problem in the analysis of Lamb wave signatures in experimental data is the fact that several different modes appear simultaneously in the signal. The modes overlap in both the <span class="hlt">frequency</span> and time domains. Attempts to <span class="hlt">separate</span> the overlapping Lamb wave signatures by conventional signal processing methods have been unsatisfactory. This paper reports an exciting alternative to conventional methods. Severely overlapping Lamb waves are found to be readily <span class="hlt">separable</span> by Bayesian parameter estimation. The authors have used linear-chirped Gaussian-windowed sinusoids as models of each Lamb wave mode. The <span class="hlt">separation</span> algorithm allows each mode to be examined individually.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22489096','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22489096"><span>Coupling and tuning of modal <span class="hlt">frequencies</span> in direct current biased microelectromechanical systems arrays</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kambali, Prashant N.; Swain, Gyanadutta; Pandey, Ashok Kumar; Buks, Eyal; Gottlieb, Oded</p> <p>2015-08-10</p> <p>Understanding the coupling of different modal <span class="hlt">frequencies</span> and their tuning mechanisms has become essential to design multi-<span class="hlt">frequency</span> MEMS devices. In this work, we fabricate a MEMS beam with fixed boundaries <span class="hlt">separated</span> from two side electrodes and a bottom electrode. Subsequently, we perform experiments to obtain the <span class="hlt">frequency</span> <span class="hlt">variation</span> of in-plane and out-of-plane mechanical modes of the microbeam with respect to both DC bias and laser heating. We show that the <span class="hlt">frequencies</span> of the two modes coincide at a certain DC bias, which in turn can also be varied due to temperature. Subsequently, we develop a theoretical model to predict the <span class="hlt">variation</span> of the two modes and their coupling due to a variable gap between the microbeam and electrodes, initial tension, and fringing field coefficients. Finally, we discuss the influence of <span class="hlt">frequency</span> tuning parameters in arrays of 3, 33, and 40 microbeams, respectively. It is also found that the <span class="hlt">frequency</span> bandwidth of a microbeam array can be increased to as high as 25 kHz for a 40 microbeam array with a DC bias of 80 V.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1088603','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1088603"><span>Coexistence under positive <span class="hlt">frequency</span> dependence.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Molofsky, J.; Bever, J. D.; Antonovics, J.</p> <p>2001-01-01</p> <p>Negative <span class="hlt">frequency</span> dependence resulting from interspecific interactions is considered a driving force in allowing the coexistence of competitors. While interactions between species and genotypes can also result in positive <span class="hlt">frequency</span> dependence, positive <span class="hlt">frequency</span> dependence has usually been credited with hastening the extinction of rare types and is not thought to contribute to coexistence. In the present paper, we develop a stochastic cellular automata model that allows us to vary the scale of <span class="hlt">frequency</span> dependence and the scale of dispersal. The results of this model indicate that positive <span class="hlt">frequency</span> dependence will allow the coexistence of two species at a greater rate than would be expected from chance. This coexistence arises from the generation of banding patterns that will be stable over long time-periods. As a result, we found that positive <span class="hlt">frequency</span>-dependent interactions over local spatial scales promote coexistence over neutral interactions. This result was robust to <span class="hlt">variation</span> in boundary conditions within the simulation and to <span class="hlt">variation</span> in levels of disturbance. Under all conditions, coexistence is enhanced as the strength of positive <span class="hlt">frequency</span>-dependent interactions is increased. PMID:11217898</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6878271','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6878271"><span><span class="hlt">Variations</span> of the solar constant</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sofia, S.</p> <p>1981-12-01</p> <p>The <span class="hlt">variations</span> in data received from rocket-borne and balloon-borne instruments are discussed. Indirect techniques to measure and monitor the solar constant are presented. Emphasis is placed on the correlation of data from the Solar Maximum Mission and the Nimbus 7 satellites. Abstracts of individual items from the workshop were prepared <span class="hlt">separately</span> for the data base.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/8050378','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/8050378"><span>[<span class="hlt">Separation</span> anxiety. Theoretical considerations].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Blandin, N; Parquet, P J; Bailly, D</p> <p>1994-01-01</p> <p>The interest in <span class="hlt">separation</span> anxiety is nowadays increasing: this disorder appearing during childhood may predispose to the occurrence of anxiety disorders (such as panic disorder and agoraphobia) and major depression into adulthood. Psychoanalytic theories differ on the nature of <span class="hlt">separation</span> anxiety and its place in child development. For some authors, <span class="hlt">separation</span> anxiety must be understood as resulting from the unconscious internal conflicts inherent in the individuation process and gradual attainment of autonomy. From this point of view, the fear of loss of mother by <span class="hlt">separation</span> is not regarded as resulting from a real danger. However, Freud considers the primary experience of <span class="hlt">separation</span> from protecting mother as the prototype situation of anxiety and compares the situations generating fear to <span class="hlt">separation</span> experiences. For him, anxiety originates from two factors: the physiological fact is initiated at the time of birth but the primary traumatic situation is the <span class="hlt">separation</span> from mother. This point of view may be compared with behavioral theories. Behavioral theories suggest that <span class="hlt">separation</span> anxiety may be conditioned or learned from innate fears. In Freud's theory, the primary situation of anxiety resulting from the <span class="hlt">separation</span> from mother plays a role comparable to innate fears. Grappling with the problem of <span class="hlt">separation</span> anxiety, Bowlby emphasizes then the importance of the child's attachment to one person (mother or primary caregiver) and the fact that this attachment is instinctive. This point of view, based on the watch of infants, is akin to ethological theories on behaviour of non human primates. Bowlby especially shows that the reactions of infant <span class="hlt">separated</span> from mother evolve on three stages: the phase of protestation which may constitute the prototype of adulthood anxiety, the phase of desperation which may be the prototype of depression, and the phase of detachment. He emphasizes so the role of early <span class="hlt">separations</span> in the development of vulnerability to depression</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7330631','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/7330631"><span>Isotope <span class="hlt">separation</span> by photochromatography</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Suslick, K.S.</p> <p>1975-10-03</p> <p>A photochromatographic method for isotope <span class="hlt">separation</span> is described. An isotopically mixed molecular species is adsorbed on an adsorptive surface, and the adsorbed molecules are irradiated with radiation of a predetermined wavelength which will selectively excite desired isotopic species. Sufficient energy is transferred to the excited molecules to desorb them from the surface and thus <span class="hlt">separate</span> them from the undesired isotopic species. The method is particularly applicable to the <span class="hlt">separation</span> of hydrogen isotopes. (BLM)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/862772','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/862772"><span>Isotope <span class="hlt">separation</span> by photochromatography</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Suslick, Kenneth S.</p> <p>1977-01-01</p> <p>An isotope <span class="hlt">separation</span> method which comprises physically adsorbing an isotopically mixed molecular species on an adsorptive surface and irradiating the adsorbed molecules with radiation of a predetermined wavelength which will selectively excite a desired isotopic species. Sufficient energy is transferred to the excited molecules to desorb them from the surface and thereby <span class="hlt">separate</span> them from the unexcited undesired isotopic species. The method is particularly applicable to the <span class="hlt">separation</span> of hydrogen isotopes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6008666','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6008666"><span>Membrane <span class="hlt">separation</span> systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Baker, R.W.; Cussler, E.L.; Eykamp, W.; Koros, W.J.; Riley, R.L.; Strathman, R.H.</p> <p>1991-01-01</p> <p>This book discusses developments and future directions in the field of membrane <span class="hlt">separation</span> systems. It describes research needed to bring energy-saving membrane <span class="hlt">separation</span> processes to technical and commercial readiness for commercial acceptance within the next 5 to 20 years. The assessment was conducted by a group of six internationally known membrane <span class="hlt">separations</span> experts who examined the worldwide status of research in seven major membrane areas. These encompassed four mature technology areas: reverse osmosis, microfiltration, ultrafiltration, and electrodialysis; two developing areas: gas <span class="hlt">separation</span> and pervaporation; and one emerging technology; facilitated transport.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=MSFC-9807329&hterms=Hemoglobin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DHemoglobin','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=MSFC-9807329&hterms=Hemoglobin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DHemoglobin"><span>The ADvanced <span class="hlt">SEParation</span> (ADSEP)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1998-01-01</p> <p>The ADvanced <span class="hlt">SEParation</span> (ADSEP) commercial payload is making use of major advances in <span class="hlt">separation</span> technology: The Phase Partitioning Experiment (PPE); the Micorencapsulation experiment; and the Hemoglobin <span class="hlt">Separation</span> Experiment (HSE). Using ADSEP, commercial researchers will attempt to determine the partition coefficients for model particles in a two-phase system. With this information, researchers can develop a higher resolution, more effective cell isolation procedure that can be used for many different types of research and for improved health care. The advanced <span class="hlt">separation</span> technology is already being made available for use in ground-based laboratories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860011197','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860011197"><span>Automatic oscillator <span class="hlt">frequency</span> control system</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, S. F. (Inventor)</p> <p>1985-01-01</p> <p>A <span class="hlt">frequency</span> control system makes an initial correction of the <span class="hlt">frequency</span> of its own timing circuit after comparison against a <span class="hlt">frequency</span> of known accuracy and then sequentially checks and corrects the <span class="hlt">frequencies</span> of several voltage controlled local oscillator circuits. The timing circuit initiates the machine cycles of a central processing unit which applies a <span class="hlt">frequency</span> index to an input register in a modulo-sum <span class="hlt">frequency</span> divider stage and enables a multiplexer to clock an accumulator register in the divider stage with a cyclical signal derived from the oscillator circuit being checked. Upon expiration of the interval, the processing unit compares the remainder held as the contents of the accumulator against a stored zero error constant and applies an appropriate correction word to a correction stage to shift the <span class="hlt">frequency</span> of the oscillator being checked. A signal from the accumulator register may be used to drive a phase plane ROM and, with periodic shifts in the applied <span class="hlt">frequency</span> index, to provide <span class="hlt">frequency</span> shift keying of the resultant output signal. Interposition of a phase adder between the accumulator register and phase plane ROM permits phase shift keying of the output signal by periodic <span class="hlt">variation</span> in the value of a phase index applied to one input of the phase adder.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22413033','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22413033"><span>Modulating action of low <span class="hlt">frequency</span> oscillations on high <span class="hlt">frequency</span> instabilities in Hall thrusters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Liqiu, Wei E-mail: weiliqiu@hit.edu.cn; Liang, Han; Ziyi, Yang; Jing, Li; Yong, Cao; Daren, Yu; Jianhua, Du</p> <p>2015-02-07</p> <p>It is found that the low <span class="hlt">frequency</span> oscillations have modulating action on high <span class="hlt">frequency</span> instabilities in Hall thrusters. The physical mechanism of this modulation is discussed and verified by numerical simulations. Theoretical analyses indicate that the wide-range fluctuations of plasma density and electric field associated with the low <span class="hlt">frequency</span> oscillations affect the electron drift velocity and anomalous electron transport across the magnetic field. The amplitude and <span class="hlt">frequency</span> of high <span class="hlt">frequency</span> oscillations are modulated by low <span class="hlt">frequency</span> oscillations, which show the periodic <span class="hlt">variation</span> in the time scale of low <span class="hlt">frequency</span> oscillations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AdSpR..58.2052T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AdSpR..58.2052T"><span>Atmospheric electric field <span class="hlt">variations</span> and lower ionosphere disturbance during the total solar eclipse of 2010 July 11</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tacza, José C.; Raulin, Jean-Pierre; Macotela, Edith L.; Norabuena, Edmundo O.; Fernandez, Germán</p> <p>2016-11-01</p> <p>In this paper, we study the <span class="hlt">variations</span> of atmospheric electric field during the total solar eclipse (TSE) of July 11, 2010, at Complejo Astronómico El Leoncito (CASLEO). These <span class="hlt">variations</span> observed with two identical sensors <span class="hlt">separated</span> by 0.4 km, show a significant increase (∼55 V/m) when compared with averaged values measured during previous and subsequent fair weather days. Furthermore, identical changes are detected on the measured phases of Very Low <span class="hlt">Frequency</span> waves received at CASLEO. The latter suggests a possible connection between the lower ionosphere and the lower atmosphere during the period of the eclipse.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.P43D..01G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.P43D..01G"><span>Low-<span class="hlt">Frequency</span> Electromagnetic Sounding for Planetary Volatiles (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grimm, R. E.</p> <p>2013-12-01</p> <p>EM sounding is divided by loss tangent << 1 (surface-penetrating radars) and >> 1 (inductive methods). The former have high resolution and responses dominated by dielectric permittivity. They have been useful for sounding the polar caps of Mars and are very promising to image the shells of icy satellites as well as the uppermost crusts of silicate bodies. The latter have poorer resolution but greater penetration depth, responses dominated by electrical conductivity, and are the subject of this talk. Low-<span class="hlt">frequency</span> inductive methods are further divided by comparing the source-receiver <span class="hlt">separation</span> to the skin depth. Large <span class="hlt">separations</span> are parametric in <span class="hlt">frequency</span> so that the <span class="hlt">variation</span> of EM response with <span class="hlt">frequency</span> is translated to change in conductivity with depth. Parametric soundings can exploit natural sources from the solar wind, magnetosphere, ionosphere, or atmosphere. Small source-sensor <span class="hlt">separations</span> are geometric with transmitter-receiver positions: both conductivity and permittivity can be recovered as a function of <span class="hlt">frequency</span> (a dielectric spectrum), but at greater resource requirements. Subsurface liquid water is an optimal low-<span class="hlt">frequency</span> EM target because even small quantities of dissolved ions make it a powerful electrical conductor compared to dry, resistive, silicate crusts. Water at kms or even tens of kms can be detected using the magnetotelluric, geomagnetic-depth sounding, or wave-tilt methods: these are all natural-source soundings using different combinations of field components and receiver geometries. If natural sources are weak or absent, a transmitter can be used to obtain high SNR; the time-domain EM (TDEM) method has been used extensively for terrestrial groundwater exploration. Using a ballistically deployed 200-m diameter transmitter loop, TDEM can detect groundwater at depths of several km. If landed in a region of strong local crustal magnetism, the characteristic Larmor <span class="hlt">frequency</span> of liquid water can be detected with a TDEM-like setup using</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10125946','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10125946"><span>Adventures in maceral <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dyrkacz, G.R.</p> <p>1994-02-01</p> <p>Progress has been made in recent years in the science of maceral <span class="hlt">separation</span>. However, there are many areas that can be improved and new areas investigated. Power of density gradient centrifugation to physically resolve macerals and submaceral species coupled with other instrumental techniques is attractive for defining the limits of coal heterogeneity as well as investigating the ability of other <span class="hlt">separation</span> methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4031314','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4031314"><span>Method for <span class="hlt">separating</span> isotopes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Jepson, B.E.</p> <p>1975-10-21</p> <p>Isotopes are <span class="hlt">separated</span> by contacting a feed solution containing the isotopes with a cyclic polyether wherein a complex of one isotope is formed with the cyclic polyether, the cyclic polyether complex is extracted from the feed solution, and the isotope is thereafter <span class="hlt">separated</span> from the cyclic polyether.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4241817','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4241817"><span>URANIUM <span class="hlt">SEPARATION</span> PROCESS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>McVey, W.H.; Reas, W.H.</p> <p>1959-03-10</p> <p>The <span class="hlt">separation</span> of uranium from an aqueous solution containing a water soluble uranyl salt is described. The process involves adding an alkali thiocyanate to the aqueous solution, contacting the resulting solution with methyl isobutyl ketons and <span class="hlt">separating</span> the resulting aqueous and organic phase. The uranium is extracted in the organic phase as UO/sub 2/(SCN)/sub/.</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_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></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_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" 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_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> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980228196','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980228196"><span>Vanguard Satellite <span class="hlt">Separation</span> Mechanisms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baumann, Robert C.</p> <p>1961-01-01</p> <p>Early in the Vanguard program it became apparent that a thoroughly reliable means of <span class="hlt">separating</span> the satellite packages from the third-stage rocket would be required. A completely self -contained standard mechanism was developed with redundant firing circuits for use on both test vehicles and satellite-launching vehicles. A change in the experimental objectives of the test-vehicle payload units necessitated modification of some of the standard <span class="hlt">separation</span> mechanisms. A strap, pull-pin, girth-ring <span class="hlt">separation</span> device was developed which employed the basic actuation of the standard mechanisms. Evidence of residual burning of the third stage made it necessary to delay <span class="hlt">separation</span> longer than the time designed into the long-delay <span class="hlt">separation</span> device. The standard <span class="hlt">separation</span> mechanism was modified and integrated with the satellite command receiver system so that a ground command after third-stage burnout would cause <span class="hlt">separation</span>. Flight performance of the various <span class="hlt">separation</span> mechanisms proved their reliability; they performed without failure in all Vanguard launchings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=krugman&pg=2&id=EJ046893','ERIC'); return false;" href="http://eric.ed.gov/?q=krugman&pg=2&id=EJ046893"><span>Working with <span class="hlt">Separation</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>Krugman, Dorothy C.</p> <p>1971-01-01</p> <p>Discusses the role of the caseworker in providing support to children experiencing <span class="hlt">separation</span> from their families and emphasizes the need to recognize that there are differences between those <span class="hlt">separation</span> experiences dictated by the needs of children and those dictated by arbitrary or noncasework factors. (AJ)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6165886','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6165886"><span>Overview of membrane <span class="hlt">separations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Noble, R.D.</p> <p>1987-01-01</p> <p>The field of membrane <span class="hlt">separations</span> is discussed. The major membrane types and applications are outlined. The outlook with respect to research activities and commercial applications is surveyed. The advantages and disadvantages of this <span class="hlt">separation</span> process are discussed. Certain applications where membranes may save energy and improve productivity are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/672515','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/672515"><span><span class="hlt">Separators</span> for flywheel rotors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Bender, D.A.; Kuklo, T.C.</p> <p>1998-07-07</p> <p>A <span class="hlt">separator</span> forms a connection between the rotors of a concentric rotor assembly. This <span class="hlt">separator</span> allows for the relatively free expansion of outer rotors away from inner rotors while providing a connection between the rotors that is strong enough to prevent disassembly. The rotor assembly includes at least two rotors referred to as inner and outer flywheel rings or rotors. This combination of inner flywheel ring, <span class="hlt">separator</span>, and outer flywheel ring may be nested to include an arbitrary number of concentric rings. The <span class="hlt">separator</span> may be a segmented or continuous ring that abuts the ends of the inner rotor and the inner bore of the outer rotor. It is supported against centrifugal loads by the outer rotor and is affixed to the outer rotor. The <span class="hlt">separator</span> is allowed to slide with respect to the inner rotor. It is made of a material that has a modulus of elasticity that is lower than that of the rotors. 10 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/871676','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/871676"><span><span class="hlt">Separators</span> for flywheel rotors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Bender, Donald A.; Kuklo, Thomas C.</p> <p>1998-01-01</p> <p>A <span class="hlt">separator</span> forms a connection between the rotors of a concentric rotor assembly. This <span class="hlt">separator</span> allows for the relatively free expansion of outer rotors away from inner rotors while providing a connection between the rotors that is strong enough to prevent disassembly. The rotor assembly includes at least two rotors referred to as inner and outer flywheel rings or rotors. This combination of inner flywheel ring, <span class="hlt">separator</span>, and outer flywheel ring may be nested to include an arbitrary number of concentric rings. The <span class="hlt">separator</span> may be a segmented or continuous ring that abuts the ends of the inner rotor and the inner bore of the outer rotor. It is supported against centrifugal loads by the outer rotor and is affixed to the outer rotor. The <span class="hlt">separator</span> is allowed to slide with respect to the inner rotor. It is made of a material that has a modulus of elasticity that is lower than that of the rotors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/570515','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/570515"><span>Substituted polyacetylene <span class="hlt">separation</span> membrane</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Pinnau, I.; Morisato, Atsushi</p> <p>1998-01-13</p> <p>A <span class="hlt">separation</span> membrane is described which is useful for gas <span class="hlt">separation</span>, particularly <span class="hlt">separation</span> of C{sub 2+} hydrocarbons from natural gas. The invention encompasses the membrane itself, methods of making it and processes for using it. The membrane comprises a polymer having repeating units of a hydrocarbon-based, disubstituted polyacetylene, having the general formula shown in the accompanying diagram, wherein R{sub 1} is chosen from the group consisting of C{sub 1}-C{sub 4} alkyl and phenyl, and wherein R{sub 2} is chosen from the group consisting of hydrogen and phenyl. In the most preferred embodiment, the membrane comprises poly(4-methyl-2-pentyne) [PMP]. The membrane exhibits good chemical resistance and has super-glassy properties with regard to <span class="hlt">separating</span> certain large, condensable permeant species from smaller, less-condensable permeant species. The membranes may also be useful in other fluid <span class="hlt">separations</span>. 4 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/871320','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/871320"><span>Substituted polyacetylene <span class="hlt">separation</span> membrane</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Pinnau, Ingo; Morisato, Atsushi</p> <p>1998-01-13</p> <p>A <span class="hlt">separation</span> membrane useful for gas <span class="hlt">separation</span>, particularly <span class="hlt">separation</span> of C.sub.2+ hydrocarbons from natural gas. The invention encompasses the membrane itself, methods of making it and processes for using it. The membrane comprises a polymer having repeating units of a hydrocarbon-based, disubstituted polyacetylene, having the general formula: ##STR1## wherein R.sub.1 is chosen from the group consisting of C.sub.1 -C.sub.4 alkyl and phenyl, and wherein R.sub.2 is chosen from the group consisting of hydrogen and phenyl. In the most preferred embodiment, the membrane comprises poly(4-methyl-2-pentyne) ›PMP!. The membrane exhibits good chemical resistance and has super-glassy properties with regard to <span class="hlt">separating</span> certain large, condensable permeant species from smaller, less-condensable permeant species. The membranes may also be useful in other fluid <span class="hlt">separations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830025064','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830025064"><span>Isothermal <span class="hlt">separation</span> processes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>England, C.</p> <p>1982-01-01</p> <p>The isothermal processes of membrane <span class="hlt">separation</span>, supercritical extraction and chromatography were examined using availability analysis. The general approach was to derive equations that identified where energy is consumed in these processes and how they compare with conventional <span class="hlt">separation</span> methods. These <span class="hlt">separation</span> methods are characterized by pure work inputs, chiefly in the form of a pressure drop which supplies the required energy. Equations were derived for the energy requirement in terms of regular solution theory. This approach is believed to accurately predict the work of <span class="hlt">separation</span> in terms of the heat of solution and the entropy of mixing. It can form the basis of a convenient calculation method for optimizing membrane and solvent properties for particular applications. Calculations were made on the energy requirements for a membrane process <span class="hlt">separating</span> air into its components.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8759E..0IS','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8759E..0IS"><span>Dynamic measurement technology in object <span class="hlt">separate</span> experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Song, Jin Cheng; Liang, Yajun; Guo, Lei; Sun, Zengyu</p> <p>2013-01-01</p> <p>In this paper, a novel experimental method is proposed in order to verify the availability and reliability in <span class="hlt">separate</span> system. To measure the position-change caused by the fault-mode machine-<span class="hlt">separate</span> of the electric isolator plug and to know the real switch process of the important component, the ground <span class="hlt">separate</span> experiment is required to simulate the real object <span class="hlt">separate</span> process and to obtain the relative position of isolate component under different <span class="hlt">separate</span> parameter. In the experiment, a position measurement system based on high speed photograph principle is introduced which has hardware, software and gauging method of photograph measure system. A in-situ measurement system is set up by two high speed camera in order to synchronized image collection of <span class="hlt">separate</span> process. After extracting, matching, coordinate and position calculating to the image, a relative position of the isolator component at the time of <span class="hlt">separate</span> process can be deduced. The relative <span class="hlt">separate</span> speed at this time can be calculated by the position parameter. The measurement system can be tested by the three-axis standard revolving stage. The results of the measurement experiment show that camera response <span class="hlt">frequency</span> is 1000Hz, the relative error of position measurement is less than 5%, the relative error of speed measurement is less than 5% which can meet demands of experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=267220','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=267220"><span>HILIC <span class="hlt">separation</span> mechanisms of tetracyclines on amino bonded silica column</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Effects of mobile phase <span class="hlt">variations</span> on the chromatographic <span class="hlt">separation</span> on amino bonded silica column in hydrophilic interaction chromatography (HILIC) were investigated for four zwitterionic tetracyclines (TCs): oxytetracycline, doxycycline, chlortetracycline and tetracycline. A mixed-mode retention m...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/863332','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/863332"><span>Process for phase <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Comolli, Alfred G.</p> <p>1979-01-01</p> <p>This invention provides a continuous process for <span class="hlt">separating</span> a gaseous phase from a hydrocarbon liquid containing carbonaceous particulates and gases. The liquid is fed to a cylindrical <span class="hlt">separator</span>, with the gaseous phase being removed therefrom as an overhead product, whereas the hydrocarbon liquid and the particulates are withdrawn as a bottoms product. By feeding the liquid tangentially to the <span class="hlt">separator</span> and maintaining a particulate-liquid slurry downward velocity of from about 0.01 to about 0.25 fps in the <span class="hlt">separator</span>, a total solids weight percent in the slurry of from about 0.1 to about 30%, a slurry temperature of from about 550.degree. to about 900.degree. F., a slurry residence time in the <span class="hlt">separator</span> of from about 30 to about 360 seconds, and a length/diameter ratio for the <span class="hlt">separator</span> of from about 20/1 to about 50/1, so that the characterization factor, .alpha., defined as ##STR1## DOES NOT EXCEED ABOUT 48 (.degree.R sec.sup.2)/ft, the deposit of carbonaceous materials on the interior surface of the <span class="hlt">separator</span> may be substantially eliminated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28157979','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28157979"><span>Quantum <span class="hlt">frequency</span> bridge: high-accuracy characterization of a nearly-noiseless parametric <span class="hlt">frequency</span> converter.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Burenkov, Ivan A; Gerrits, Thomas; Lita, Adriana; Nam, Sae Woo; Krister Shalm, L; Polyakov, Sergey V</p> <p>2017-01-23</p> <p>We demonstrate an efficient and inherently ultra-low noise <span class="hlt">frequency</span> conversion via a parametric sum <span class="hlt">frequency</span> generation. Due to the wide <span class="hlt">separation</span> between the input and pump <span class="hlt">frequencies</span> and the low pump <span class="hlt">frequency</span> relative to the input photons, the upconversion results in only ≈100 background photons per hour. To measure such a low rate, we introduced a dark count reduction algorithm for an optical transition edge sensor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/863918','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/863918"><span>Chromatographic hydrogen isotope <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Aldridge, Frederick T.</p> <p>1981-01-01</p> <p>Intermetallic compounds with the CaCu.sub.5 type of crystal structure, particularly LaNiCo.sub.4 and CaNi.sub.5, exhibit high <span class="hlt">separation</span> factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope <span class="hlt">separation</span> colum. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale mutli-stage chromatographic <span class="hlt">separation</span> process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5325204','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/5325204"><span>Chromatographic hydrogen isotope <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Aldridge, F.T.</p> <p></p> <p>Intermetallic compounds with the CaCu/sub 5/ type of crystal structure, particularly LaNiCo/sub 4/ and CaNi/sub 5/, exhibit high <span class="hlt">separation</span> factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope <span class="hlt">separation</span> column. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale multi-stage chromatographic <span class="hlt">separation</span> process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen cn produce large quantities of heavy water at an effective cost for use in heavy water reactors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5838708','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5838708"><span>Asymmetric gas <span class="hlt">separation</span> membranes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Malon, R. F.; Zampini, A.</p> <p>1984-12-04</p> <p>Asymmetric gas <span class="hlt">separation</span> membranes of materials having selective permeation of at least one gas of a gaseous mixture over that of one or more remaining gases of the gaseous mixture, exhibit significantly improved permeation selectivities for the at least one gas when the asymmetric membrane is contacted on one or both surfaces with an effective amount of a Lewis acid. The improved asymmetric gas <span class="hlt">separation</span> membranes, process for producing the improved membrane, and processes utilizing such membranes for selectively <span class="hlt">separating</span> at least one gas from a gaseous mixture by permeation are disclosed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6010897','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6010897"><span>Asymmetric gas <span class="hlt">separation</span> membranes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Malon, R. F.; Zampini, A.</p> <p>1984-09-18</p> <p>Asymmetric gas <span class="hlt">separation</span> membranes of materials having selective permeation of at least one gas of a gaseous mixture over that of one or more remaining gases of the gaseous mixture, exhibit significantly improved permeation selectivities for the at least one gas when the asymmetric membrane is contacted on one or both surfaces with an effective amount of a Br nsted-Lowry acid. The improved asymmetric gas <span class="hlt">separation</span> membranes, process for producing the improved membrane, and processes utilizing such membranes for selectively <span class="hlt">separating</span> at least one gas from a gaseous mixture by permeation are disclosed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/7038297','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/7038297"><span>Enhance <span class="hlt">separations</span> with electricity</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Muralidhara, H.S.</p> <p>1994-05-01</p> <p>To satisfy growing environmental regulations, control energy costs, or just to stay competitive, one must improve existing <span class="hlt">separation</span> technologies and make them more efficient. New challenges in food processing and requirements for novel purification technologies in the biotech industry also will require more efficient <span class="hlt">separation</span> techniques. This paper discusses some enhanced <span class="hlt">separation</span> processes based on the application of an electric field in the combined-fields approach. In a combined-fields approach, the emphasis is on the generation of additional driving forces to work simultaneously with the conventional driving force of the process. Here the authors concentrate on the application of an electric field to generate the additional driving force.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.1133S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.1133S"><span>Assessing the value of multi-receiver low-<span class="hlt">frequency</span> electromagnetic-induction (EMI) measurement for assessing <span class="hlt">variation</span> in soil moisture content in field experiments with winter wheat (Triticum aestivum)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shanahan, Peter; Binley, Andrew; Dodd, Ian; Whalley, Richard; Watts, Chris; Ashton, Rhys; Ober, Eric</p> <p>2014-05-01</p> <p>In large plant breeding field trials with multiple genotypes, measuring soil water status (an indicator of crop water uptake) by conventional techniques (e.g. core extraction and penetration resistance) is limited by the cost and effort needed to achieve sufficient replication to apply robust statistical analysis. Geophysical methods may provide a more cost-effective means of more assessing valuable information about soil water status for such studies. We present here results from a field experiment using geophysical techniques for remote mapping of soil water content on sandy loam and silt loam soils in spring/summer 2013 in the UK. The aim of the study was to assess electromagnetic-induction (EMI) conductivity measurements for sensitivity to <span class="hlt">variations</span> in shallow soil electrical properties and the spatial and temporal mapping of soil water. The CMD Mini-Explorer (GF Instruments) operates with three receiver coils at fixed distances from a transmitter coil (0.32 m, 0.71 m, 1.2 m). Measurement of magnetic field quadrature in horizontal coplanar (HC) and vertical coplanar (VC) of the three receiver coils provides six depths of investigation for the given coil spacing cumulative sensitivities. At the two field sites the instrument was applied to measuring apparent electrical conductivity (ECa) below 7.0 x 1.8 m plots consisting of 23 rain fed winter wheat cultivars and bare soil fallow control plots. These plots were sown in March 2013 and organised into a randomised block design. Electrical resistivity tomography (ERT) surveys along 15 m transects were also conducted at the two sites in order to compare EMI measured ECa. Our results show that progressive soil drying at both sites due to crop uptake significantly decreased (p<0.05) soil ECa. The difference in soil ECa as a result of water uptake between cultivars was found to be significant (p<0.05) from one of the coil configurations (coil spacing 1.8m in HC mode), and only at the silty loam site (no significant</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16740314','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16740314"><span>Estimation of short-time cross-correlation between <span class="hlt">frequency</span> bands of event related EEG.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zygierewicz, J; Mazurkiewicz, J; Durka, P J; Franaszczuk, P J; Crone, N E</p> <p>2006-10-30</p> <p>Simultaneous <span class="hlt">variations</span> of the event-related power changes (ERD/ERS) are often observed in a number of <span class="hlt">frequency</span> bands. ERD/ERS measures are usually based on the relative changes of power in a given single <span class="hlt">frequency</span> band. Within such an approach one cannot answer questions concerning the mutual relations between the band-power <span class="hlt">variations</span> observed in different <span class="hlt">frequency</span> bands. This paper addresses the problem of estimating and assessing the significance of the average cross-correlation between ERD/ERS phenomena occurring in two <span class="hlt">frequency</span> bands. The cross-correlation function in a natural way also provides estimation of the delay between ERD/ERS in those bands. The proposed method is based on estimating the short-time cross-correlation function between relative changes of power in two selected <span class="hlt">frequency</span> bands. The cross-correlation function is estimated in each trial <span class="hlt">separately</span> and then averaged across trials. The significance of those mean cross-correlation functions is evaluated by means of a nonparametric test. The basic properties of the method are presented on simulated signals, and an example application to real EEG and ECoG signals is given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24528520','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24528520"><span>Geographic <span class="hlt">variation</span> in animal colour polymorphisms and its role in speciation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McLean, Claire A; Stuart-Fox, Devi</p> <p>2014-11-01</p> <p>Polymorphic species, in which multiple variants coexist within a population, are often used as model systems in evolutionary biology. Recent research has been dominated by the hypothesis that polymorphism can be a precursor to speciation. To date, the majority of research regarding polymorphism and speciation has focused on whether polymorphism is maintained within a population or whether morphs within populations may diverge to form <span class="hlt">separate</span> species (sympatric speciation); however, the geographical context of speciation in polymorphic systems is likely to be both diverse and complex. In this review, we draw attention to the geographic <span class="hlt">variation</span> in morph composition and <span class="hlt">frequencies</span> that characterises many, if not most polymorphic species. Recent theoretical and empirical developments suggest that such <span class="hlt">variation</span> in the number, type and <span class="hlt">frequency</span> of morphs present among populations can increase the probability of speciation. Thus, the geographical context of a polymorphism requires a greater research focus. Here, we review the prevalence, causes and evolutionary consequences of geographic <span class="hlt">variation</span> in polymorphism in colour-polymorphic animal species. The prevalence and nature of geographic <span class="hlt">variation</span> in polymorphism suggests that polymorphism may be a precursor to and facilitate speciation more commonly than appreciated previously. We argue that a better understanding of the processes generating geographic <span class="hlt">variation</span> in polymorphism is vital to understanding how polymorphism can promote speciation.</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://www.osti.gov/scitech/servlets/purl/870500','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/870500"><span>Molten salt electrolyte <span class="hlt">separator</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Kaun, Thomas D.</p> <p>1996-01-01</p> <p>A molten salt electrolyte/<span class="hlt">separator</span> for battery and related electrochemical systems including a molten electrolyte composition and an electrically insulating solid salt dispersed therein, to provide improved performance at higher current densities and alternate designs through ease of fabrication.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730018322','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730018322"><span>Inorganic <span class="hlt">separator</span> technology program</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smatko, J. S.; Weaver, R. D.; Kalhammer, F. R.</p> <p>1973-01-01</p> <p>Testing and failure analyses of silver zinc cells with largely inorganic <span class="hlt">separators</span> were performed. The results showed that the wet stand and cycle life objective of the silver-zinc cell development program were essentially accomplished and led to recommendations for cell composition, design, and operation that should yield further improvement in wet and cycle life. A series of advanced inorganic materials was successfully developed and formulated into rigid and semiflexible <span class="hlt">separator</span> samples. Suitable screening tests for evaluation of largely inorganic <span class="hlt">separators</span> were selected and modified for application to the <span class="hlt">separator</span> materials. The results showed that many of these formulations are potentially superior to previously used materials and permitted selection of three promising materials for further evaluation in silver-zinc cells.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910000108&hterms=sensor+natural&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dsensor%2Bnatural','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910000108&hterms=sensor+natural&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dsensor%2Bnatural"><span>Laminar-<span class="hlt">Separation</span> Sensor</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Manuel, G. S.; Carraway, D. L.; Lee, C. C.</p> <p>1991-01-01</p> <p>Reduction of viscous drag on airplanes explores limits of practical applications of natural laminar flow. Wind-tunnel and flight tests conducted to explore abilities of hot-film sensors to identify <span class="hlt">separation</span> of laminar flow as principal mode of amplification of instability leading to transition from laminar to turbulent flow. Two different laminar-<span class="hlt">separation</span>-sensor configurations developed and used to detect boundary-layer transitions. Results show hot-film laminar-<span class="hlt">separation</span>-sensor technique viable means for detecting existence of transition as well as for indicating reversed flow in laminar-<span class="hlt">separation</span> bubble. Refinement of sensor configurations provides tools necessary to explore, in all speed regimes, practical limits of laminar-flow applications and viscous-drag-reduction technology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3040254','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3040254"><span><span class="hlt">Separable</span> Arrowhead Microneedles</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chu, Leonard Y.; Prausnitz, Mark R.</p> <p>2010-01-01</p> <p>Hypodermic needles cause pain and bleeding, produce biohazardous sharp waste and require trained personnel. To address these issues, we introduce <span class="hlt">separable</span> arrowhead microneedles that rapidly and painlessly deliver drugs and vaccines to the skin. These needles are featured by micron-size sharp tips mounted on blunt shafts. Upon insertion in the skin, the sharp-tipped polymer arrowheads encapsulating drug <span class="hlt">separate</span> from their metal shafts and remain embedded in the skin for subsequent dissolution and drug release. The blunt metal shafts can then be discarded. Due to rapid <span class="hlt">separation</span> of the arrowhead tips from the shafts within seconds, administration using arrowhead microneedles can be carried out rapidly, while drug release kinetics can be independently controlled based on <span class="hlt">separable</span> arrowhead formulation. Thus, drug and vaccine delivery using arrowhead microneedles are designed to offer a quick, convenient, safe and potentially self-administered method of drug delivery as an alternative to hypodermic needles. PMID:21047538</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820014433','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820014433"><span>Booster <span class="hlt">separation</span> motor</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1981-01-01</p> <p>The design, development, fabrication, testing, evaluation and flight qualification of the space shuttle booster <span class="hlt">separation</span> motor is discussed. Delivery of flight hardware to support the research and development flights of the space shuttle is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/862495','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/862495"><span><span class="hlt">Separation</span> by solvent extraction</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Holt, Jr., Charles H.</p> <p>1976-04-06</p> <p>17. A process for <span class="hlt">separating</span> fission product values from uranium and plutonium values contained in an aqueous solution, comprising adding an oxidizing agent to said solution to secure uranium and plutonium in their hexavalent state; contacting said aqueous solution with a substantially water-immiscible organic solvent while agitating and maintaining the temperature at from -1.degree. to -2.degree. C. until the major part of the water present is frozen; continuously <span class="hlt">separating</span> a solid ice phase as it is formed; <span class="hlt">separating</span> a remaining aqueous liquid phase containing fission product values and a solvent phase containing plutonium and uranium values from each other; melting at least the last obtained part of said ice phase and adding it to said <span class="hlt">separated</span> liquid phase; and treating the resulting liquid with a new supply of solvent whereby it is practically depleted of uranium and plutonium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1007483','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1007483"><span>Microsystem capillary <span class="hlt">separations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>TeGrotenhuis, Ward E [Kennewick, WA; Wegeng, Robert S [Richland, WA; Whyatt, Greg A [West Richland, WA; Stenkamp, Victoria S [Richland, WA; Gauglitz, Phillip A [Richland, WA</p> <p>2003-12-23</p> <p>Laminated, multiphase <span class="hlt">separators</span> and contactors having wicking structures and gas flow channels are described. Some preferred embodiments are combined with microchannel heat exchange. Integrated systems containing these components are also part of the present invention.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19680000513','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19680000513"><span><span class="hlt">Separator</span> for alkaline batteries</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hoyt, H. W.; Pfluger, H. L.</p> <p>1968-01-01</p> <p><span class="hlt">Separator</span> compositions have been tested as components of three-plate silver-zinc oxide cells in a standard cycling test. Six materials meet imposed requirements, giving cycling performance superior to cellophane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110004876','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110004876"><span>Monitored <span class="hlt">separation</span> device</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jackson, George William (Inventor); Willson, Richard Coale (Inventor); Fox, George Edward (Inventor)</p> <p>2011-01-01</p> <p>A device for <span class="hlt">separating</span> and purifying useful quantities of particles comprises: a. an anolyte reservoir connected to an anode, the anolyte reservoir containing an electrophoresis buffer; b. a catholyte reservoir connected to a cathode, the catholyte reservoir also containing the electrophoresis buffer; c. a power supply connected to the anode and to the cathode; d. a column having a first end inserted into the anolyte reservoir, a second end inserted into the catholyte reservoir, and containing a <span class="hlt">separation</span> medium; e. a light source; f. a first optical fiber having a first fiber end inserted into the <span class="hlt">separation</span> medium, and having a second fiber end connected to the light source; g. a photo detector; h. a second optical fiber having a third fiber end inserted into the <span class="hlt">separation</span> medium, and having a fourth fiber end connected to the photo detector; and i. an ion-exchange membrane in the anolyte reservoir.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA083895','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA083895"><span><span class="hlt">Frequency</span> Spreading in Underwater Acoustic Signal Transmission.</span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>1980-04-15</p> <p>acoustic signal transmitted and received underwater J-2 J.2 Signal spectrum computing block diagram. J-3 Chapter I. <span class="hlt">Frequency</span> spreading 1.0 Introduction... transmitted <span class="hlt">frequency</span> can be expected in the received signal [1] - [18]. This <span class="hlt">frequency</span> spreading behavior is the result of the amplitude and phase...result of phase modulation of the transmitted sinusoid by the moving surface, and the <span class="hlt">separation</span> between the spectral lines at the receiving point is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26788945','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26788945"><span><span class="hlt">Separation</span> of Craniopagus Twins.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Johnson, Reuben; Weir, Philip</p> <p>2016-01-01</p> <p><span class="hlt">Separation</span> of craniopagus twins is fraught by ethical issues. The surgery is high risk and may involve the sacrifice of one twin. We review surgical successes in <span class="hlt">separation</span> of craniopagus twins and consider ethical and legal concepts affecting the decision to undertake such procedures. Our discussion considers how Gillett's potentiality principle and the concept of moral permissibility may be used to arrive at fair and realistic decisions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1019538','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1019538"><span>Hydrogen <span class="hlt">separation</span> process</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Mundschau, Michael; Xie, Xiaobing; Evenson, IV, Carl; Grimmer, Paul; Wright, Harold</p> <p>2011-05-24</p> <p>A method for <span class="hlt">separating</span> a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to a hydrogen <span class="hlt">separation</span> membrane system comprising a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for <span class="hlt">separating</span> a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to an integrated water gas shift/hydrogen <span class="hlt">separation</span> membrane system wherein the hydrogen <span class="hlt">separation</span> membrane system comprises a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for pretreating a membrane, comprising: heating the membrane to a desired operating temperature and desired feed pressure in a flow of inert gas for a sufficient time to cause the membrane to mechanically deform; decreasing the feed pressure to approximately ambient pressure; and optionally, flowing an oxidizing agent across the membrane before, during, or after deformation of the membrane. A method of supporting a hydrogen <span class="hlt">separation</span> membrane system comprising selecting a hydrogen <span class="hlt">separation</span> membrane system comprising one or more catalyst outer layers deposited on a hydrogen transport membrane layer and sealing the hydrogen <span class="hlt">separation</span> membrane system to a porous support.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4830493','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4830493"><span><span class="hlt">SEPARATIONS</span> BY ELECTRODIALYSIS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Webb, W.H.; Vie, J.D.</p> <p>1962-06-12</p> <p>A method is given for <span class="hlt">separating</span> cesium, cerium, zirconium, and uranyl ions frora a common solution by electrodialysis. An anion exchange membrane and a cation exchange membrane are placed on either side of the feed solution compartment; the former is in electrolytic contact with an anode and the latter with cathode. On acidification of the feed solution to a critical value of 0.5 N and passage of a current from the anode to the cathode, the desired <span class="hlt">separations</span> tske place. (AEC)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997PhDT.......219D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997PhDT.......219D"><span>Numerical study of lift augmentation in massively <span class="hlt">separated</span> turbulent flows with forcing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Denny, Andrew Gregory</p> <p></p> <p>At high angles of attack the flow over any lifting body experiences massive <span class="hlt">separation</span>. The resulting shear layers naturally tend to roll up into large vortical structures. The presence and motion of these structures has a significant impact on the continuing flowfield development. By applying an artificial forcing to the shedding shear layer the rollup can be intensified or reduced, and the entire vorticity field may be altered. Control of these vortical structures by forcing to enhance lift has been the goal of numerous investigations, and some progress has been made in understanding how an unsteady forcing can be used to advantage. This study describes work done in determining the effectiveness of using computational simulations to model massively <span class="hlt">separated</span>, turbulent unsteady flowfields subject to small-amplitude mechanical forcing. Algorithm development and validation highlight certain concerns that arise in the modeling of such unsteady flowfields using the Reynolds-Averaged Navier-Stokes equations, and questions of grid density, numerical diffusion, timestep size, and turbulence modeling are addressed with a suite of sample calculations. Simulation of flowfields undergoing mechanical forcing by flap is accomplished using an overset grid methodology with the flow solver. Excellent agreement is demonstrated for flow over a NACA 63sb3-018 airfoil with a small flap placed near the leading edge <span class="hlt">separation</span> point. Computed values of the unforced lift and drag coefficients agree with given experimental values to less than 2%. Forcing <span class="hlt">frequencies</span> for the experimental configuration were in the range of global shedding <span class="hlt">frequency</span>, and the maximum <span class="hlt">variation</span> of the aerodynamic coefficients was seen when the forcing <span class="hlt">frequency</span> was equal to the shedding <span class="hlt">frequency</span>. Excellent agreement with experiment is also found for the cases involving forcing, and the data is used to explain the effect of forcing in terms of a global receptivity mechanism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=child+AND+anxiety+AND+attachment+AND+disorder&pg=5&id=EJ550617','ERIC'); return false;" href="http://eric.ed.gov/?q=child+AND+anxiety+AND+attachment+AND+disorder&pg=5&id=EJ550617"><span>Autistic Children's Responses to <span class="hlt">Separation</span> and Reunion with Their Mothers.</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>Dissanayake, Cheryl; Crossley, Stella A.</p> <p>1997-01-01</p> <p>A study of 16 children with autism, 16 typical children, and 16 children with Downs syndrome (ages 3-6) investigated children's responses to <span class="hlt">separation</span> and reunion with their mothers. No differences were found between groups; however, the children with disabilities showed more individual <span class="hlt">variation</span> in <span class="hlt">separation</span> and reunion patterns. (Author/CR)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT.......548S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT.......548S"><span>Gulf stream <span class="hlt">separation</span> dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schoonover, Joseph</p> <p></p> <p>Climate models currently struggle with the more traditional, coarse ( O(100 km) ) representation of the ocean. In these coarse ocean simulations, western boundary currents are notoriously difficult to model accurately. The modeled Gulf Stream is typically seen exhibiting a mean pathway that is north of observations, and is linked to a warm sea-surface temperature bias in the Mid-Atlantic Bight. Although increased resolution ( O(10 km) ) improves the modeled Gulf Stream position, there is no clean recipe for obtaining the proper pathway. The 70 year history of literature on the Gulf Stream <span class="hlt">separation</span> suggests that we have not reached a resolution on the dynamics that control the current's pathway just south of the Mid-Atlantic Bight. Without a concrete knowledge on the <span class="hlt">separation</span> dynamics, we cannot provide a clean recipe for accurately modeling the Gulf Stream at increased resolutions. Further, any reliable parameterization that yields a realistic Gulf Stream path must express the proper physics of <span class="hlt">separation</span>. The goal of this dissertation is to determine what controls the Gulf Stream <span class="hlt">separation</span>. To do so, we examine the results of a model intercomparison study and a set of numerical regional terraforming experiments. It is argued that the <span class="hlt">separation</span> is governed by local dynamics that are most sensitive to the steepening of the continental shelf, consistent with the topographic wave arrest hypothesis of Stern (1998). A linear extension of Stern's theory is provided, which illustrates that wave arrest is possible for a continuously stratified fluid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000MNRAS.312..301L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000MNRAS.312..301L"><span>Carter <span class="hlt">separable</span> electromagnetic fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lynden-Bell, D.</p> <p>2000-02-01</p> <p>The purely electromagnetic analogue in flat space of Kerr's metric in general relativity is only rarely considered. Here we carry out in flat space a programme similar to Carter's investigation of metrics in general relativity in which the motion of a charged particle is <span class="hlt">separable</span>. We concentrate on the <span class="hlt">separability</span> of the motion (be it classical, relativistic or quantum) of a charged particle in electromagnetic fields that lie in planes through an axis of symmetry. In cylindrical polar coordinates (t,R,φ,z) the four-vector potential takes the form [formmu2] is the unit toroidal vector. The forms of the functions Φ(R,z) and A(R,z) are sought that allow <span class="hlt">separable</span> motion. This occurs for relativistic motion only when AR,Φ and A2-Φ2 are all of the <span class="hlt">separable</span> form ζ(λ)-η(μ)]/(λ-μ), where ζ and η are arbitrary functions, and λ and μ are spheroidal coordinates or degenerations thereof. The special forms of A and Φ that allow this are deduced. They include the Kerr metric analogue, with E+iB=-∇{q[(r-ia).(r-ia)]-1/2}. Rather more general electromagnetic fields allow <span class="hlt">separation</span> when the motion is non-relativistic. The investigation is extended to fields that lie in parallel planes. Connections to Larmor's theorem are remarked upon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1158501','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1158501"><span>Organic <span class="hlt">Separation</span> Test Results</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Russell, Renee L.; Rinehart, Donald E.; Peterson, Reid A.</p> <p>2014-09-22</p> <p><span class="hlt">Separable</span> organics have been defined as “those organic compounds of very limited solubility in the bulk waste and that can form a <span class="hlt">separate</span> liquid phase or layer” (Smalley and Nguyen 2013), and result from three main solvent extraction processes: U Plant Uranium Recovery Process, B Plant Waste Fractionation Process, and Plutonium Uranium Extraction (PUREX) Process. The primary organic solvents associated with tank solids are TBP, D2EHPA, and NPH. There is concern that, while this organic material is bound to the sludge particles as it is stored in the tanks, waste feed delivery activities, specifically transfer pump and mixer pump operations, could cause the organics to form a <span class="hlt">separated</span> layer in the tank farms feed tank. Therefore, Washington River Protection Solutions (WRPS) is experimentally evaluating the potential of organic solvents <span class="hlt">separating</span> from the tank solids (sludge) during waste feed delivery activities, specifically the waste mixing and transfer processes. Given the Hanford Tank Waste Treatment and Immobilization Plant (WTP) waste acceptance criteria per the Waste Feed Acceptance Criteria document (24590-WTP-RPT-MGT-11-014) that there is to be “no visible layer” of <span class="hlt">separable</span> organics in the waste feed, this would result in the batch being unacceptable to transfer to WTP. This study is of particular importance to WRPS because of these WTP requirements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.5607V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.5607V"><span>Can accelerometers detect mass <span class="hlt">variations</span> in Amazonian trees?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Emmerik, Tim; Steele-Dunne, Susan; Gentine, Pierre; Guerin, Marceau; Hut, Rolf; Oliveira, Rafael; van de Giesen, Nick</p> <p>2016-04-01</p> <p>The mass of trees is influenced by physiological processes within the tree (e.g. transpiration and root water uptake), as well as external loads (e.g. intercepted precipitation). Recent studies have found diurnal <span class="hlt">variations</span> in radar backscatter over vegetated areas, which might be attributed to mass changes of the vegetation layer. Field measurements are required to study the driving processes. This study aims to use measured three-dimensional displacement and acceleration of trees, to detect and quantify their diurnal (bio)mass <span class="hlt">variations</span>. Accelerometers and dendrometers were installed on seven different tree species in the Amazon rainforest. Trees were selected to cover a broad range of wood density. Using spectral analysis, the governing <span class="hlt">frequencies</span> in the acceleration time series were found. The governing <span class="hlt">frequencies</span> showed a diurnal pattern, as well as a change during precipitation events. Our results suggest that we can <span class="hlt">separate</span> and potentially quantify tree mass changes due to (1) internal water redistribution and (2) intercepted precipitation. This will allow further investigation of the effect of precipitation and water stress on tree dynamics in forest canopies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10950452','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10950452"><span>Microsatellite DNA <span class="hlt">variation</span> in Bornean orangutans (Pongo pygmaeus).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Warren, K S; Nijmian, I J; Lenstra, J A; Swan, R A; Heriyanto; den Boer, M</p> <p>2000-04-01</p> <p>Orangutans (Pongo pygmaeus) on the islands of Borneo and Sumatra are considered two <span class="hlt">separate</span> subspecies. However, the genetic relationships between isolated populations on Borneo are not clear. This study determined the extent of <span class="hlt">variation</span> within the Bornean subspecies of orangutan, using microsatellite DNA analysis. Blood samples were collected from 96 individuals of known origin from East, West and Central Kalimantan. Human microsatellite primer pairs located at human map position D2S141, D4S431, D 11S925, D16S420 and D17S791 were suitable for use in primates. D4S431 appeared monomorphic for all orangutans. In three cases (D2S141 East and West and D16S420 West), a highly significant excess of homozygous allele <span class="hlt">frequencies</span> was detected, but with other primer pairs no significant difference in allele <span class="hlt">frequencies</span> occurred. We conclude that the divergence between the different populations on Borneo is less than the <span class="hlt">variation</span> within the populations. There was also evidence that inbreeding occurred within the populations.</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('http://hdl.handle.net/2060/19670000360','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19670000360"><span>Pressure levels and pulsation <span class="hlt">frequencies</span> can be varied on high pressure/<span class="hlt">frequency</span> testing device</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Routson, J. W.</p> <p>1967-01-01</p> <p>Hydraulic system components test device obtains a pulsating pressure from a hydraulic actuator that is being driven by a vibration exciter of sufficient force and displacement. Input to the exciter controls the <span class="hlt">frequency</span> of pressure <span class="hlt">variation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780006421','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780006421"><span>Flow <span class="hlt">separation</span> detector</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mateer, G. C.; Brosh, A. (Inventor)</p> <p>1977-01-01</p> <p>An arrangement for sensing the fluid <span class="hlt">separation</span> along a surface which employs a thermally insulating element having a continuous surface blending into and forming a part of the fluid flow surface is described. A sudden decrease in the temperature of the downstream sensor conductor and concomitant increase in the temperature of the upstream sensor conductor is an indication of the <span class="hlt">separation</span>. When the temperatures are returned to the state achieved during normal flow, the indicator thereby indicates the normal, attached fluid flow. The conductors may be, for example, wires or thin films, and should be within the viscous sub-layer of the expected fluid flow. A single heater and several pairs of sensors and corresponding sensor conductors may be used to detect not only the fluid flow and the <span class="hlt">separation</span>, but the direction of the fluid flow, over the fluid flow surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/865879','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/865879"><span>Membrane <span class="hlt">separation</span> of hydrocarbons</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Chang, Y. Alice; Kulkarni, Sudhir S.; Funk, Edward W.</p> <p>1986-01-01</p> <p>Mixtures of heavy oils and light hydrocarbons may be <span class="hlt">separated</span> by passing the mixture through a polymeric membrane. The membrane which is utilized to effect the <span class="hlt">separation</span> comprises a polymer which is capable of maintaining its integrity in the presence of hydrocarbon compounds and which has been modified by being subjected to the action of a sulfonating agent. Sulfonating agents which may be employed will include fuming sulfuric acid, chlorosulfonic acid, sulfur trioxide, etc., the surface or bulk modified polymer will contain a degree of sulfonation ranging from about 15 to about 50%. The <span class="hlt">separation</span> process is effected at temperatures ranging from about ambient to about 100.degree. C. and pressures ranging from about 50 to about 1000 psig.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...621971R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...621971R"><span>Mass <span class="hlt">Separation</span> by Metamaterials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Restrepo-Flórez, Juan Manuel; Maldovan, Martin</p> <p>2016-02-01</p> <p>Being able to manipulate mass flow is critically important in a variety of physical processes in chemical and biomolecular science. For example, <span class="hlt">separation</span> and catalytic systems, which requires precise control of mass diffusion, are crucial in the manufacturing of chemicals, crystal growth of semiconductors, waste recovery of biological solutes or chemicals, and production of artificial kidneys. Coordinate transformations and metamaterials are powerful methods to achieve precise manipulation of molecular diffusion. Here, we introduce a novel approach to obtain mass <span class="hlt">separation</span> based on metamaterials that can sort chemical and biomolecular species by cloaking one compound while concentrating the other. A design strategy to realize such metamaterial using homogeneous isotropic materials is proposed. We present a practical case where a mixture of oxygen and nitrogen is manipulated using a metamaterial that cloaks nitrogen and concentrates oxygen. This work lays the foundation for molecular mass <span class="hlt">separation</span> in biophysical and chemical systems through metamaterial devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998SPIE.3327...32L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998SPIE.3327...32L"><span><span class="hlt">Variations</span> of hybrid damping</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lam, Margaretha J.; Inman, Daniel J.; Saunders, William R.</p> <p>1998-06-01</p> <p>Damping is important to structures and can be achieved through the addition of viscoelastic materials (VEM). The damping of the VEM is enhanced if a constraining layer is attached to the VEM. If this constraining layer is active, the treatment is called active constrained layer damping (ACLD). In the last few years, ACLD has proven to be superior in vibration control to active or passive damping. The active element makes ACLD more effective than passive constrained layer damping. It also provides a fail-safe in case of breakdown of the active element that is not present for purely active control. It is shown that the control effort needed to damp vibration using ACLD can be significantly higher than purely active control. In order to combine the inherent damping of passive control with the effectiveness of the active element, this paper will explore different <span class="hlt">variations</span> of active, passive and hybrid damping. Some of the <span class="hlt">variations</span> include: passive constrained layer damping (PCLD) <span class="hlt">separate</span> from active element but on the same side of beam, PCLD <span class="hlt">separate</span> from active on the opposite side of the beam, and active element underneath PCLD. The discretized system equations will be obtained using assumed modes method and Lagrange's equation. The damping will be modeled using the Golla-Hughes-McTavish (GHM) method. The optimal placement and size of the active, passive, ACLD and hybrid treatments will be found using different schemes. The issue of overshoot and settling time of the output and control force using LQR will be addressed, as well as the control effort, passive and active vibration suppression, and LQR cost function. It will be shown that the hybrid treatments are capable of greater vibration control for lower control effort for different optimization schemes. 31</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JMMM..422...37K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JMMM..422...37K"><span>Mathematical modelling of <span class="hlt">frequency</span>-dependent hysteresis and energy loss of FeBSiC amorphous alloy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koprivica, Branko; Milovanovic, Alenka; Mitrovic, Nebojsa</p> <p>2017-01-01</p> <p>The aim of this paper is to present a novel mathematical model of <span class="hlt">frequency</span>-dependent magnetic hysteresis. The major hysteresis loop in this model is represented by the ascending and descending curve over an arctangent function. The parameters of the hysteresis model have been calculated from a measured hysteresis loop of the FeBSiC amorphous alloy sample. A number of measurements have been performed with this sample at different <span class="hlt">frequencies</span> of the sinusoidal excitation magnetic field. A <span class="hlt">variation</span> of the coercive magnetic field with the <span class="hlt">frequency</span> has been observed and used in the modelling of <span class="hlt">frequency</span>-dependent hysteresis with the proposed model. A comparison between measured and modelled hysteresis loops has been presented. Additionally, the areas of the obtained hysteresis loops, representing the energy loss per unit volume, have been calculated and the dependence of the energy loss on the <span class="hlt">frequency</span> is shown. Furthermore, two models of the <span class="hlt">frequency</span> dependence of the coercivity and two models of the energy loss <span class="hlt">separation</span> have been used for fitting the experimental and simulation results. The relations between these models and their parameters have been observed and analysed. Also, the relations between parameters of the hysteresis model and the parameters of the energy loss <span class="hlt">separation</span> models have been analysed and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6054404','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6054404"><span><span class="hlt">Separation</span> of organic liquids</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pasternak, M.; Bartels, C.R.; Reale, J. Jr.</p> <p>1989-01-17</p> <p>The method is described comprising: concentrating a charge solution containing methanol and either dimethyl carbonate or methyl t-butyl ether oxygenate by, maintaining a membrane of non-porous <span class="hlt">separating</span> layer of cast polyvinyl alcohol which has been crosslinked with an aliphatic polyaldehyde containing at least three carbon atoms including those in the aldehyde groups; maintaining a pressure drop across the non-porous <span class="hlt">separating</span> layer of polyvinyl alcohol; passing a charge aqueous solution containing methanol and either dimethyl carbonate or methyl t-butyl ether oxygenate into contact with the high pressure side of the non-porous <span class="hlt">separating</span> layer of polyvinyl alcohol having properties which enable at least a portion of the methanol in the charge solution and a lesser portion of oxygenate to pass by pervaporation through the non-porous <span class="hlt">separating</span> layer of polyvinyl alcohol as a lean mixture containing more methanol and less oxygenate than are present in the charge solution and the charge solution is converted to a rich liquid containing less methanol and more oxygenate than are present in the charge solution; recovering as permeate from the low pressure side of the non-porous <span class="hlt">separating</span> layer of polyvinyl alcohol the lean mixture containing more methanol and less oxygenate than are present in the charge solution, the lean mixture being recovered in vapor phase at a pressure below the vapor pressure thereof; and recovering as retentate from the high pressure side of the non-porous <span class="hlt">separating</span> layer the rich liquid containing a lower methanol content and a higher oxygenate content than are present in the charge solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050182046','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050182046"><span>Unsteady Aerodynamic Response of a Linear Cascade of Airfoils in <span class="hlt">Separated</span> Flow</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Capece, Vincent R.; Ford, Christopher; Bone, Christopher; Li, Rui</p> <p>2004-01-01</p> <p>The overall objective of this research program was to investigate methods to modify the leading edge <span class="hlt">separation</span> region, which could lead to an improvement in aeroelastic stability of advanced airfoil designs. The airfoil section used is representative of current low aspect ratio fan blade tip sections. The experimental potion of this study investigated <span class="hlt">separated</span> zone boundary layer from removal through suction slots. Suction applied to a cavity in the vicinity of the <span class="hlt">separation</span> onset point was found to be the most effective location. The computational study looked into the influence of front camber on flutter stability. To assess the influence of the change in airfoil shape on stability the work-per-cycle was evaluated for torsion mode oscillations. It was shown that the front camberline shape can be an important factor for stabilizing the predicted work-per-cycle and reducing the predicted extent of the <span class="hlt">separation</span> zone. In addition, data analysis procedures are discussed for reducing data acquired in experiments that involve periodic unsteady data. This work was conducted in support of experiments being conducted in the NASA Glenn Research Center Transonic Flutter Cascade. The spectral block averaging method is presented. This method is shown to be able to account for <span class="hlt">variations</span> in airfoil oscillation <span class="hlt">frequency</span> that can occur in experiments that force oscillate the airfoils to simulate flutter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/305618','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/305618"><span><span class="hlt">Separation</span> membrane development</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lee, M.W.</p> <p>1998-08-01</p> <p>A ceramic membrane has been developed to <span class="hlt">separate</span> hydrogen from other gases. The method used is a sol-gel process. A thin layer of dense ceramic material is coated on a coarse ceramic filter substrate. The pore size distribution in the thin layer is controlled by a densification of the coating materials by heat treatment. The membrane has been tested by permeation measurement of the hydrogen and other gases. Selectivity of the membrane has been achieved to <span class="hlt">separate</span> hydrogen from carbon monoxide. The permeation rate of hydrogen through the ceramic membrane was about 20 times larger than Pd-Ag membrane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4329797','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4329797"><span>SULFIDE METHOD PLUTONIUM <span class="hlt">SEPARATION</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Duffield, R.B.</p> <p>1958-08-12</p> <p>A process is described for the recovery of plutonium from neutron irradiated uranium solutions. Such a solution is first treated with a soluble sullide, causing precipitation of the plutoniunn and uraniunn values present, along with those impurities which form insoluble sulfides. The precipitate is then treated with a solution of carbonate ions, which will dissolve the uranium and plutonium present while the fission product sulfides remain unaffected. After <span class="hlt">separation</span> from the residue, this solution may then be treated by any of the usual methods, such as formation of a lanthanum fluoride precipitate, to effect <span class="hlt">separation</span> of plutoniunn from uranium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/863259','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/863259"><span>Gas <span class="hlt">separation</span> membranes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Schell, William J.</p> <p>1979-01-01</p> <p>A dry, fabric supported, polymeric gas <span class="hlt">separation</span> membrane, such as cellulose acetate, is prepared by casting a solution of the polymer onto a shrinkable fabric preferably formed of synthetic polymers such as polyester or polyamide filaments before washing, stretching or calendering (so called griege goods). The supported membrane is then subjected to gelling, annealing, and drying by solvent exchange. During the processing steps, both the fabric support and the membrane shrink a preselected, controlled amount which prevents curling, wrinkling or cracking of the membrane in flat form or when spirally wound into a gas <span class="hlt">separation</span> element.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4296252','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4296252"><span>WET FLUORIDE <span class="hlt">SEPARATION</span> METHOD</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Seaborg, G.T.; Gofman, J.W.; Stoughton, R.W.</p> <p>1958-11-25</p> <p>The <span class="hlt">separation</span> of U/sup 233/ from thorium, protactinium, and fission products present in neutron-irradiated thorium is accomplished by dissolving the irradiated materials in aqueous nitric acid, adding either a soluble fluoride, iodate, phosphate, or oxalate to precipltate the thorium, <span class="hlt">separating</span> the precipltate from the solution, and then precipitating uranlum and protactinium by alkalizing the solution. The uranium and protactinium precipitate is removcd from the solution and dissolved in nitric acid. The uranyl nitrate may then be extracted from the acid solution by means of ether, and the protactinium recovered from the aqueous phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4273849','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4273849"><span><span class="hlt">SEPARATION</span> OF FLUID MIXTURES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Lipscomb, R.; Craig, A.; Labrow, S.; Dunn, J.F.</p> <p>1958-10-28</p> <p>An apparatus is presented for <span class="hlt">separating</span> gaseous mixtures by selectively freezing a constituent of the mixture and subsequently <span class="hlt">separating</span> the frozen gas. The gas mixture is passed through a cylinder fltted with a cooling jacket, causing one gas to freeze on the walls of the cylinder. A set of scraper blades are provided in the interior of the cyllnder, and as the blades oscillate, the frozen gas is scraped to the bottom of the cylinder. Means are provided for the frozen material to pass into a heating chamber where it is vaporized and the product gas collected.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100014083','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100014083"><span>Multistage Electrophoretic <span class="hlt">Separators</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thomas, Nathan; Doyle, John F.; Kurk, Andy; Vellinger, John C.; Todd, Paul</p> <p>2006-01-01</p> <p>A multistage electrophoresis apparatus has been invented for use in the <span class="hlt">separation</span> of cells, protein molecules, and other particles and solutes in concentrated aqueous solutions and suspensions. The design exploits free electrophoresis but overcomes the deficiencies of prior free-electrophoretic <span class="hlt">separators</span> by incorporating a combination of published advances in mathematical modeling of convection, sedimentation, electro-osmotic flow, and the sedimentation and aggregation of droplets. In comparison with other electrophoretic <span class="hlt">separators</span>, these apparatuses are easier to use and are better suited to <span class="hlt">separation</span> in relatively large quantities characterized in the art as preparative (in contradistinction to smaller quantities characterized in the art as analytical). In a multistage electrophoretic <span class="hlt">separator</span> according to the invention, an applied vertical steady electric field draws the electrically charged particles of interest from within a cuvette to within a collection cavity that has been moved into position of the cuvette. There are multiple collection cavities arranged in a circle; each is aligned with the cuvette for a prescribed short time. The multistage, short-migration-path character of the invention solves, possibly for the first time, the fluid-instability problems associated with free electrophoresis. The figure shows a prototype multistage electrophoretic <span class="hlt">separator</span> that includes four sample stations and five collection stages per sample. At each sample station, an aqueous solution or suspension containing charged species to be <span class="hlt">separated</span> is loaded into a cuvette, which is machined into a top plate. The apparatus includes a lower plate, into which 20 collection cavities have been milled. Each cavity is filled with an electrophoresis buffer solution. For the collection of an electrophoretic fraction, the lower plate is rotated to move a designated collection cavity into alignment with the opening of the cuvette. An electric field is then applied between a non</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5206469','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5206469"><span><span class="hlt">Separation</span> techniques: Chromatography</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Coskun, Ozlem</p> <p>2016-01-01</p> <p>Chromatography is an important biophysical technique that enables the <span class="hlt">separation</span>, identification, and purification of the components of a mixture for qualitative and quantitative analysis. Proteins can be purified based on characteristics such as size and shape, total charge, hydrophobic groups present on the surface, and binding capacity with the stationary phase. Four <span class="hlt">separation</span> techniques based on molecular characteristics and interaction type use mechanisms of ion exchange, surface adsorption, partition, and size exclusion. Other chromatography techniques are based on the stationary bed, including column, thin layer, and paper chromatography. Column chromatography is one of the most common methods of protein purification. PMID:28058406</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1163750','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1163750"><span><span class="hlt">Separators</span> for electrochemical cells</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Carlson, Steven Allen; Anakor, Ifenna Kingsley</p> <p>2014-11-11</p> <p>Provided are <span class="hlt">separators</span> for use in an electrochemical cell comprising (a) an inorganic oxide and (b) an organic polymer, wherein the inorganic oxide comprises organic substituents. Preferably, the inorganic oxide comprises an hydrated aluminum oxide of the formula Al.sub.2O.sub.3.xH.sub.2O, wherein x is less than 1.0, and wherein the hydrated aluminum oxide comprises organic substituents, preferably comprising a reaction product of a multifunctional monomer and/or organic carbonate with an aluminum oxide, such as pseudo-boehmite and an aluminum oxide. Also provided are electrochemical cells comprising such <span class="hlt">separators</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940015888','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940015888"><span>Spiral fluid <span class="hlt">separator</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Robertson, Glen A. (Inventor)</p> <p>1993-01-01</p> <p>A fluid <span class="hlt">separator</span> for <span class="hlt">separating</span> particulate matter such as contaminates is provided which includes a series of spiral tubes of progressively decreasing cross sectional area connected in series. Each tube has an outlet on the outer curvature of the spiral. As fluid spirals down a tube, centrifugal force acts to force the heavier particulate matter to the outer wall of the tube, where it exits through the outlet. The remaining, and now cleaner, fluid reaches the next tube, which is smaller in cross sectional area, where the process is repeated. The fluid which comes out the final tube is diminished of particulate matter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040089029&hterms=protein+chromatography&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dprotein%2Bchromatography','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040089029&hterms=protein+chromatography&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dprotein%2Bchromatography"><span>Electrochromatographic <span class="hlt">separation</span> of proteins</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Basak, S. K.; Velayudhan, A.; Kohlmann, K.; Ladisch, M. R.; Mitchell, C. A. (Principal Investigator)</p> <p>1995-01-01</p> <p>We have developed a modified electrochromatography system which minimizes Joule heating at electric field strengths up to 125 V/cm. A non-linear equilibrium model is described which incorporates electrophoretic mobility, hydrodynamic flow velocity, and an electrically induced concentration polarization at the surface of the stationary phase. This model is able to provide useful estimates of protein retention time and velocity in a column packed with Sephadex gel and subjected to an electric field. A correlation of electrophoretic mobility of peptide and proteins with respect to their charge, molecular mass, and asymmetry enables the selection of solute target molecules for electrochromatographic <span class="hlt">separations</span>. Good <span class="hlt">separation</span> of protein mixtures have been obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6799208','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6799208"><span>Oscillation <span class="hlt">frequencies</span> of solar models</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cox, A.N.; Guzik, J.A.; Kidman, R.B.</p> <p>1988-01-01</p> <p>Two solar models have been constructed, one with no diffusion of the atomic nuclei, and another including diffusive element <span class="hlt">separation</span>. The opacity at the bottom of the convection zone was increased 15--20 percent (within its theoretical uncertainty) to obtain a few microhertz agreement with observed p-mode <span class="hlt">frequencies</span>. Original helium mass fractions were 0.291 and 0.289 for the no-diffusion and diffusion models, respectively. The diffusion model evolved to a surface Y = 0.256 at the solar age, and the original Z value of 0.0200 decreased to 0.0179. Agreement of l = 0 and 2 p-mode <span class="hlt">frequency</span> <span class="hlt">separations</span> with those observed is good. The g-mode nonadiabatic solutions do not have equal period spacing until high radial order. The lowest order modes are more visible if they all have the same kinetic energy. High central temperatures, produce over 9 SNUs from the B and 1.5 SNUs from the Be reactions. Models with iron condensed-out below the convection zone, and with WIMPs cooling the central regions to reduce the SNUs, agree less well with p-mode <span class="hlt">frequency</span> <span class="hlt">separations</span>. 53 refs., 6 figs., 4 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/wri994232/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/wri994232/"><span>Depth-Duration <span class="hlt">Frequency</span> of Precipitation for Oklahoma</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Tortorelli, Robert L.; Rea, Alan; Asquith, William H.</p> <p>1999-01-01</p> <p>A regional <span class="hlt">frequency</span> analysis was conducted to estimate the depth-duration <span class="hlt">frequency</span> of precipitation for 12 durations in Oklahoma (15, 30, and 60 minutes; 1, 2, 3, 6, 12, and 24 hours; and 1, 3, and 7 days). Seven selected <span class="hlt">frequencies</span>, expressed as recurrence intervals, were investigated (2, 5, 10, 25, 50, 100, and 500 years). L-moment statistics were used to summarize depth-duration data and to determine the appropriate statistical distributions. Three different rain-gage networks provided the data (15minute, 1-hour, and 1-day). The 60-minute, and 1-hour; and the 24-hour, and 1-day durations were analyzed <span class="hlt">separately</span>. Data were used from rain-gage stations with at least 10-years of record and within Oklahoma or about 50 kilometers into bordering states. Precipitation annual maxima (depths) were determined from the data for 110 15-minute, 141 hourly, and 413 daily stations. The L-moment statistics for depths for all durations were calculated for each station using unbiased L-mo-ment estimators for the mean, L-scale, L-coefficient of <span class="hlt">variation</span>, L-skew, and L-kur-tosis. The relation between L-skew and L-kurtosis (L-moment ratio diagram) and goodness-of-fit measures were used to select the <span class="hlt">frequency</span> distributions. The three-parameter generalized logistic distribution was selected to model the <span class="hlt">frequencies</span> of 15-, 30-, and 60-minute annual maxima; and the three-parameter generalized extreme-value distribution was selected to model the <span class="hlt">frequencies</span> of 1-hour to 7-day annual maxima. The mean for each station and duration was corrected for the bias associated with fixed interval recording of precipitation amounts. The L-scale and spatially averaged L-skew statistics were used to compute the location, scale, and shape parameters of the selected distribution for each station and duration. The three parameters were used to calculate the depth-duration-<span class="hlt">frequency</span> relations for each station. The precipitation depths for selected <span class="hlt">frequencies</span> were contoured from weighted depth</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://www.osti.gov/scitech/biblio/4212218','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4212218"><span><span class="hlt">SEPARATION</span> BY ADSORPTION</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Lowe, C.S.</p> <p>1959-06-16</p> <p><span class="hlt">Separation</span> of Pu from fission products by adsorption on hydrous aluminum silicate is described. The Pu in a HNO/sub 3/ solution is oxidized to the hexavalent state and contacted with the silicate which adsorbs fission products. (T.R.H.)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/253862','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/253862"><span>Molten salt electrolyte <span class="hlt">separator</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Kaun, T.D.</p> <p>1996-07-09</p> <p>The patent describes a molten salt electrolyte/<span class="hlt">separator</span> for battery and related electrochemical systems including a molten electrolyte composition and an electrically insulating solid salt dispersed therein, to provide improved performance at higher current densities and alternate designs through ease of fabrication. 5 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25243599','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25243599"><span>Chemotactic <span class="hlt">separation</span> of enzymes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dey, Krishna Kanti; Das, Sambeeta; Poyton, Matthew F; Sengupta, Samudra; Butler, Peter J; Cremer, Paul S; Sen, Ayusman</p> <p>2014-12-23</p> <p>We demonstrate a procedure for the <span class="hlt">separation</span> of enzymes based on their chemotactic response toward an imposed substrate concentration gradient. The <span class="hlt">separation</span> is observed within a two-inlet, five-outlet microfluidic network, designed to allow mixtures of active (ones that catalyze substrate turnover) and inactive (ones that do not catalyze substrate turnover) enzymes, labeled with different fluorophores, to flow through one of the inlets. Substrate solution prepared in phosphate buffer was introduced through the other inlet of the device at the same flow rate. The steady-state concentration profiles of the enzymes were obtained at specific positions within the outlets of the microchannel using fluorescence microscopy. In the presence of a substrate concentration gradient, active enzyme molecules migrated preferentially toward the substrate channel. The excess migration of the active enzyme molecules was quantified in terms of an enrichment coefficient. Experiments were carried out with different pairs of enzymes. Coupling the physics of laminar flow of liquid and molecular diffusion, multiphysics simulations were carried out to estimate the extent of the chemotactic <span class="hlt">separation</span>. Our results show that, with appropriate microfluidic arrangement, molecular chemotaxis leads to spontaneous <span class="hlt">separation</span> of active enzyme molecules from their inactive counterparts of similar charge and size.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4834101','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4834101"><span>METHOD OF <span class="hlt">SEPARATING</span> NEPTUNIUM</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Seaborg, G.T.</p> <p>1961-10-24</p> <p>plutonium in an aqueous solution containing sulfate ions. The process consists of contacting the solution with an alkali metal bromate, digesting the resulting mixture at 15 to 25 deg C for a period of time not more than that required to oxidize the neptunium, adding lanthanum ions and fluoride ions, and <span class="hlt">separating</span> the plutonium-containing precipitate thus formed from the supernatant solution. (AEC)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5306485','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/5306485"><span>Hydrogen isotope <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Bartlit, J.R.; Denton, W.H.; Sherman, R.H.</p> <p></p> <p>Disclosed is a system of four cryogenic fractional distillation columns interlinked with two equilibrators for <span class="hlt">separating</span> a DT and hydrogen feed stream into four product streams, consisting of a stream of high purity D/sub 2/, DT, T/sub 2/, and a tritium-free stream of HD for waste disposal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/864366','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/864366"><span>Hydrogen isotope <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Bartlit, John R.; Denton, William H.; Sherman, Robert H.</p> <p>1982-01-01</p> <p>A system of four cryogenic fractional distillation columns interlinked with two equilibrators for <span class="hlt">separating</span> a DT and hydrogen feed stream into four product streams, consisting of a stream of high purity D.sub.2, DT, T.sub.2, and a tritium-free stream of HD for waste disposal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED286801.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED286801.pdf"><span><span class="hlt">Separation</span> of Powers.</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>Bill of Rights in Action, 1987</p> <p>1987-01-01</p> <p>The dimensions of the <span class="hlt">separation</span> of powers principle are explored through three lessons in the subject areas of U.S. history, U.S. government, and world history. In 1748, a French nobleman, Baron de Montesquieu, wrote a book called "The Spirit of the Laws," in which he argued that there could be no liberty when all government power was…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1175026','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1175026"><span>Polymide gas <span class="hlt">separation</span> membranes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Ding, Yong; Bikson, Benjamin; Nelson, Joyce Katz</p> <p>2004-09-14</p> <p>Soluble polyamic acid salt (PAAS) precursors comprised of tertiary and quaternary amines, ammonium cations, sulfonium cations, or phosphonium cations, are prepared and fabricated into membranes that are subsequently imidized and converted into rigid-rod polyimide articles, such as membranes with desirable gas <span class="hlt">separation</span> properties. A method of enhancing solubility of PAAS polymers in alcohols is also disclosed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100024432','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100024432"><span>Lunar Soil Particle <span class="hlt">Separator</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Berggren, Mark</p> <p>2010-01-01</p> <p>The Lunar Soil Particle <span class="hlt">Separator</span> (LSPS) beneficiates soil prior to in situ resource utilization (ISRU). It can improve ISRU oxygen yield by boosting the concentration of ilmenite, or other iron-oxide-bearing materials found in lunar soils, which can substantially reduce hydrogen reduction reactor size, as well as drastically decreasing the power input required for soil heating</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=GIFT+AND+LIST&id=EJ738495','ERIC'); return false;" href="http://eric.ed.gov/?q=GIFT+AND+LIST&id=EJ738495"><span><span class="hlt">Separation</span> and Attachment</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>Honig, Alice Sterling</p> <p>2005-01-01</p> <p>Developing secure attachments with babies gives them a very special gift--the foundation for good infant mental health! In this article, the author discusses how to develop secure attachments with babies. Babies who are in the care of others during the day often suffer from <span class="hlt">separations</span> from their special adults. Thirteen "tips" to ensure that…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080004078','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080004078"><span>Alkaline battery, <span class="hlt">separator</span> therefore</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmidt, George F. (Inventor)</p> <p>1980-01-01</p> <p>An improved battery <span class="hlt">separator</span> for alkaline battery cells has low resistance to electrolyte ion transfer and high resistance to electrode ion transfer. The <span class="hlt">separator</span> is formed by applying an improved coating to an electrolyte absorber. The absorber, preferably, is a flexible, fibrous, and porous substrate that is resistant to strong alkali and oxidation. The coating composition includes an admixture of a polymeric binder, a hydrolyzable polymeric ester and inert fillers. The coating composition is substantially free of reactive fillers and plasticizers commonly employed as porosity promoting agents in <span class="hlt">separator</span> coatings. When the <span class="hlt">separator</span> is immersed in electrolyte, the polymeric ester of the film coating reacts with the electrolyte forming a salt and an alcohol. The alcohol goes into solution with the electrolyte while the salt imbibes electrolyte into the coating composition. When the salt is formed, it expands the polymeric chains of the binder to provide a film coating substantially permeable to electrolyte ion transfer but relatively impermeable to electrode ion transfer during use.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28359582','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28359582"><span><span class="hlt">Variation</span> in Recombination Rate: Adaptive or Not?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ritz, Kathryn R; Noor, Mohamed A F; Singh, Nadia D</p> <p>2017-03-27</p> <p>Rates of meiotic recombination are widely variable both within and among species. However, the functional significance of this <span class="hlt">variation</span> remains largely unknown. Is the observed within-species <span class="hlt">variation</span> in recombination rate adaptive? Recent work has revealed new insight into the scale and scope of population-level <span class="hlt">variation</span> in recombination rate. These data indicate that the magnitude of within-population <span class="hlt">variation</span> in recombination is similar among taxa. The apparent similarity of the variance in recombination rate among individuals between distantly related species suggests that the relative costs and benefits of recombination that establish the upper and lower bounds may be similar across species. Here we review the current data on intraspecific <span class="hlt">variation</span> in recombination rate and discuss the molecular and evolutionary costs and benefits of recombination <span class="hlt">frequency</span>. We place this <span class="hlt">variation</span> in the context of adaptation and highlight the need for more empirical studies focused on the adaptive value of <span class="hlt">variation</span> in recombination rate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830001865','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830001865"><span>Polyvinyl alcohol membranes as alkaline battery <span class="hlt">separators</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sheibley, D. W.; Gonzalez-Sanabria, O.; Manzo, M. A.</p> <p>1982-01-01</p> <p>Polyvinly alcohol (PVA) cross-linked with aldehyde reagents yields membranes that demonstrate properties that make them suitable for use as alkaline battery <span class="hlt">separators</span>. Film properties can be controlled by the choice of cross-linker, cross-link density and the method of cross-linking. Three methods of cross-linking and their effects on film properties are discussed. Film properties can also be modified by using a copolymer of vinyl alcohol and acrylic acid as the base for the <span class="hlt">separator</span> and cross-linking it similarly to the PVA. Fillers can be incorporated into the films to further modify film properties. Results of <span class="hlt">separator</span> screening tests and cell tests for several <span class="hlt">variations</span> of PBA films are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/307877','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/307877"><span><span class="hlt">Separation</span> science and technology</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Smith, B.F.; Sauer, N.; Chamberlin, R.M.; Gottesfeld, S.; Mattes, B.R.; Li, D.Q.; Swanson, B.</p> <p>1998-12-31</p> <p>The focus of this project is the demonstration and advancement of membrane-based <span class="hlt">separation</span> and destruction technologies. The authors are exploring development of membrane systems for gas <span class="hlt">separations</span>, selective metal ion recovery, and for <span class="hlt">separation</span> or destruction of hazardous organics. They evaluated existing polymers and polymer formulations for recovery of toxic oxyanionic metals such as chromate and arsenate from selected waste streams and developed second-generation water-soluble polymeric systems for highly selective oxyanion removal and recovery. They optimized the simultaneous removal of radioactive strontium and cesium from aqueous solutions using the new nonhazardous <span class="hlt">separations</span> agents, and developed recyclable, redox-active extractants that permitted recovery of the radioactive ions into a minimal waste volume. They produced hollow fibers and fabricated prototype hollow-fiber membrane modules for applications to gas <span class="hlt">separations</span> and the liquid-liquid extraction and recovery of actinides and nuclear materials from process streams. They developed and fabricated cyclodextrin-based microporous materials that selectively absorb organic compounds in an aqueous environment; the resultant products gave pure water with organics at less than 0.05 parts per billion. They developed new, more efficient, membrane-based electrochemical reactors for use in organic destruction in process waste treatment. They addressed the need for advanced oxidation technologies based on molecular-level materials designs that selectively remove or destroy target species. They prepared and characterized surface-modified TiO{sub 2} thin films using different linking approaches to attach ruthenium photosensitizers, and they started the measurement of the photo-degradation products generated using surface modified TiO{sub 2} films in reaction with chlorophenol.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhDT.......269M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhDT.......269M"><span>Turbulent transition behavior in a <span class="hlt">separated</span> and attached-flow low pressure turbine passage</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Memory, Curtis L.</p> <p></p> <p>Various time accurate numerical simulations were conducted on the aft-loaded L1A low pressure turbine airfoil operating at Reynolds numbers presenting with fully-stalled, non-reattaching laminar <span class="hlt">separation</span>. The numerical solver TURBO was modified from its annular gas turbine simulation configuration to conduct simulations based on a linear cascade wind tunnel facility. Simulation results for the fully <span class="hlt">separated</span> flow fields revealed various turbulent decay mechanisms. <span class="hlt">Separated</span> shear layer decay, in the form of vortices forming between the shear layer and the blade wall, was shown to agree with experimental particle image velocimetry (PIV) data in terms of decay vortex size and core vorticity levels. These vortical structures eventually mix into a large recirculation zone which dominates the blade wake. Turbulent wake ex- tent and time-averaged velocity distributions agreed with PIV data. Steady-blowing vortex generating jet (VGJ) flow control was then applied to the flow fields. VGJ-induced streamwise vorticity was only present at blowing ratios above 1.5. VGJs actuated at the point of flow <span class="hlt">separation</span> on the blade wall were more effective than those actuated downstream, within the <span class="hlt">separation</span> zone. Pulsed-blowing VGJs at the upstream blade wall position were then actuated at various pulsing <span class="hlt">frequencies</span>, duty cycles, and blowing ratios. These condition <span class="hlt">variations</span> yielded differing levels of <span class="hlt">separation</span> zone mitigation. Pulsed VGJs were shown to be more effective than steady blowing VGJs at conditions of high blowing ratio, high <span class="hlt">frequency</span>, or high duty cycle, where blowing ratio had the highest level of influence on pulsed jet efficacy. The characteristic "calm zone" following the end of a given VGJ pulse was observed in simulations exhibiting high levels of <span class="hlt">separation</span> zone mitigation. Numerical velocity fields near the blade wall during this calm zone was shown to be similar to velocity fields observed in PIV data. Instantaneous numerical vorticity fields indicated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5265474','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5265474"><span>Harmonically excited orbital <span class="hlt">variations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Morgan, T.</p> <p>1985-08-06</p> <p>Rephrasing the equations of motion for orbital maneuvers in terms of Lagrangian generalized coordinates instead of Newtonian rectangular cartesian coordinates can make certain harmonic terms in the orbital angular momentum vector more readily apparent. In this formulation the equations of motion adopt the form of a damped harmonic oscillator when torques are applied to the orbit in a <span class="hlt">variationally</span> prescribed manner. The <span class="hlt">frequencies</span> of the oscillator equation are in some ways unexpected but can nonetheless be exploited through resonant forcing functions to achieve large secular <span class="hlt">variations</span> in the orbital elements. Two cases are discussed using a circular orbit as the control case: (1) large changes in orbital inclination achieved by harmonic excitation rather than one impulsive velocity change, and (2) periodic and secular changes to the longitude of the ascending node using both stable and unstable excitation strategies. The implications of these equations are also discussed for both artificial satellites and natural satellites. For the former, two utilitarian orbits are suggested, each exploiting a form of harmonic excitation. 5 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5820S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5820S"><span>High <span class="hlt">frequency</span> noise studies at the Hartousov mofette area (CZE)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmidt, Andreas; Flores-Estrella, Hortencia; Pommerencke, Julia; Umlauft, Josefine</p> <p>2014-05-01</p> <p>Ambient noise analysis has been used as a reliable tool to investigate sub-surface structures at seismological quiet regions with none or less specific seismic events. Here, we consider the acoustic signals from a single mofette at the Hartoušov area (CZE) as a noise-like high <span class="hlt">frequency</span> source caused by multiple near surface degassing processes in a restricted location. From this assumption we have used different array geometries for recording at least one hour of continuous noise. We installed triangular arrays with 3 component geophones: the first deployment consisted on two co-centric triangles with side length of 30 and 50 m with the mofette in the center; the second deployment consisted on two triangular arrays, both with side length of 30 m, co-directional to the mofette. Furthermore, we also installed profiles with 24 channels and vertical geophones locating them in different positions with respect to the mofette. In this work, we present preliminary results from the data analysis dependent on the geometry, to show the characteristics of the noise wave-field referring to <span class="hlt">frequency</span> content and propagation features, such as directionality and surface wave velocity. The spectral analysis shows that the energy is concentrated in a <span class="hlt">frequency</span> band among 10 and 40 Hz. However, in this interval there is no evidence of any exclusive fundamental <span class="hlt">frequencies</span>. From this, man-induced influences can be identified as intermittent signal peaks in narrow <span class="hlt">frequency</span> bands and can be <span class="hlt">separated</span> to receive the revised mofette wave-field record. The inversion of dispersive surface waves, that were detected by interferometric methods, provides a velocity model down to 12 m with an S-wave velocity between 160 and 180 m/s on the uppermost layer. Furthermore, the interferometric signal properties indicate that it is not possible to characterize the mofette as a punctual source, but rather as a conglomerate of multiple sources with time and location <span class="hlt">variations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21371510','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21371510"><span>Giant Crab pulses at low <span class="hlt">frequency</span>: statistics, scattering, polarization</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Smirnova, T. V.</p> <p>2010-01-01</p> <p>We carried out observations of Crab giant pulses at <span class="hlt">frequency</span> 112 MHz from 2005 till 2008 on the Large Phased Array of the Pushchino Radio Astronomy Observatory. The scattering of pulses observed in various series varies by a factor of 3: from 11 ms in November 2005 till 34 ms in September 2008. The cumulative probability distribution for the peak intensities of the giant pulses for each of these series shows that the distribution is stable and is a power law with a single slope (n = -2.3). This testifies to stability of the mechanism generating the giant pulses. The energy in the pulses is conserved; i.e., the increase in the pulse intensity is proportional to the decrease in the scattering. Refractive scintillations at low <span class="hlt">frequencies</span> in measurements with large time <span class="hlt">separation</span> lead to <span class="hlt">variations</span> in the relative number of giant pulses exceeding a given amplitude, proportional to the ratio of the mean flux densities of the pulsar in the corresponding observational series. The maximum energy of the recorded giant pulses is 2.5x10{sup 7} Jy mus. Analysis of the giant pulses observed at other <span class="hlt">frequencies</span> shows that the <span class="hlt">frequency</span> dependence of the maximum energy of the giant pulses in the range of 23 MHz-9 GHz is a power-law with index -2.2+-0.2. We measured the rotation measure using GP which is RM (-47.5+-0.4) rad/m{sup 2}, and the degree of linear polarization for pulses with measured <span class="hlt">frequency</span> modulation was 9% divide 17% for November 2005.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22233579','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22233579"><span><span class="hlt">Variational</span> integrators for electric circuits</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ober-Blöbaum, Sina; Tao, Molei; Cheng, Mulin; Owhadi, Houman; Marsden, Jerrold E.</p> <p>2013-06-01</p> <p>In this contribution, we develop a <span class="hlt">variational</span> integrator for the simulation of (stochastic and multiscale) electric circuits. When considering the dynamics of an electric circuit, one is faced with three special situations: 1. The system involves external (control) forcing through external (controlled) voltage sources and resistors. 2. The system is constrained via the Kirchhoff current (KCL) and voltage laws (KVL). 3. The Lagrangian is degenerate. Based on a geometric setting, an appropriate <span class="hlt">variational</span> formulation is presented to model the circuit from which the equations of motion are derived. A time-discrete <span class="hlt">variational</span> formulation provides an iteration scheme for the simulation of the electric circuit. Dependent on the discretization, the intrinsic degeneracy of the system can be canceled for the discrete <span class="hlt">variational</span> scheme. In this way, a <span class="hlt">variational</span> integrator is constructed that gains several advantages compared to standard integration tools for circuits; in particular, a comparison to BDF methods (which are usually the method of choice for the simulation of electric circuits) shows that even for simple LCR circuits, a better energy behavior and <span class="hlt">frequency</span> spectrum preservation can be observed using the developed <span class="hlt">variational</span> integrator.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApGeo..13..156C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApGeo..13..156C"><span>Relationship between the transition <span class="hlt">frequency</span> of local fluid flow and the peak <span class="hlt">frequency</span> of attenuation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cao, Cheng-Hao; Zhang, Hong-Bing; Pan, Yi-Xin; Teng, Xin-Bao</p> <p>2016-03-01</p> <p>Local fluid flow (LFF) at the mesoscopic scale is the main dissipation mechanism of seismic waves in heterogeneous porous media within the seismic <span class="hlt">frequency</span> band. LFF is easily influenced by the structure and boundary conditions of the porous media, which leads to different behaviors of the peak <span class="hlt">frequency</span> of attenuation. The associated transition <span class="hlt">frequency</span> can provide detailed information about the trend of LFF; therefore, research on the transition <span class="hlt">frequency</span> of LFF and its relationship with the peak <span class="hlt">frequency</span> of the corresponding attenuation (i.e., inverse of quality factor) facilitates the detailed understanding of the effect of inner structures and boundary conditions in porous media. In this study, we firstly obtain the transition <span class="hlt">frequency</span> of fluid flux based on Biot's theory of poroelasticity and the fast Fourier transform algorithm in a sample containing one repeating unit cell (RUC). We then analyze changes of these two <span class="hlt">frequencies</span> in porous media with different porous properties. Finally, we extend our analysis to the influence of the undrained boundary condition on the transition <span class="hlt">frequency</span> and peak <span class="hlt">frequency</span> in porous media with multiple RUCs. This setup can facilitate the understanding of the effect from the undrained boundary condition. Results demonstrate that these two <span class="hlt">frequencies</span> have the same trend at low water saturation, but amplitude <span class="hlt">variations</span> differ between the <span class="hlt">frequencies</span> as the amount of saturation increases. However, for cases of high water saturation, both the trend and the amplitude <span class="hlt">variation</span> of these two <span class="hlt">frequencies</span> fit well with each other.</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://hdl.handle.net/2060/20120010417','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120010417"><span>Microgravity Passive Phase <span class="hlt">Separator</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Paragano, Matthew; Indoe, William; Darmetko, Jeffrey</p> <p>2012-01-01</p> <p>A new invention disclosure discusses a structure and process for <span class="hlt">separating</span> gas from liquids in microgravity. The Microgravity Passive Phase <span class="hlt">Separator</span> consists of two concentric, pleated, woven stainless- steel screens (25-micrometer nominal pore) with an axial inlet, and an annular outlet between both screens (see figure). Water enters at one end of the center screen at high velocity, eventually passing through the inner screen and out through the annular exit. As gas is introduced into the flow stream, the drag force exerted on the bubble pushes it downstream until flow stagnation or until it reaches an equilibrium point between the surface tension holding bubble to the screen and the drag force. Gas bubbles of a given size will form a front that is moved further down the length of the inner screen with increasing velocity. As more bubbles are added, the front location will remain fixed, but additional bubbles will move to the end of the unit, eventually coming to rest in the large cavity between the unit housing and the outer screen (storage area). Owing to the small size of the pores and the hydrophilic nature of the screen material, gas does not pass through the screen and is retained within the unit for emptying during ground processing. If debris is picked up on the screen, the area closest to the inlet will become clogged, so high-velocity flow will persist farther down the length of the center screen, pushing the bubble front further from the inlet of the inner screen. It is desired to keep the velocity high enough so that, for any bubble size, an area of clean screen exists between the bubbles and the debris. The primary benefits of this innovation are the lack of any need for additional power, strip gas, or location for venting the <span class="hlt">separated</span> gas. As the unit contains no membrane, the transport fluid will not be lost due to evaporation in the process of gas <span class="hlt">separation</span>. <span class="hlt">Separation</span> is performed with relatively low pressure drop based on the large surface</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/15002083','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/15002083"><span><span class="hlt">Separation</span> of Climate Signals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kamath, C; Fodor, I</p> <p>2002-11-13</p> <p>Understanding changes in global climate is a challenging scientific problem. Simulated and observed data include signals from many sources, and untangling their respective effects is difficult. In order to make meaningful comparisons between different models, and to understand human effects on global climate, we need to isolate the effects of different sources. Recent eruptions of the El Chichon and Mt. Pinatubo volcanoes coincided with large El Nino and Southern Oscillation (ENSO) events, which complicates the <span class="hlt">separation</span> of their contributions on global temperatures. Current approaches for <span class="hlt">separating</span> volcano and ENSO signals in global mean data involve parametric models and iterative techniques [3]. We investigate alternative methods based on principal component analysis (PCA) [2] and independent component analysis (ICA) [1]. Our goal is to determine if such techniques can automatically identify the signals corresponding to the different sources, without relying on parametric models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5060071','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5060071"><span>Hydrocyclone <span class="hlt">separation</span> hydrodynamics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ivanov, A.A.; Ruzanov, S.R.; Lunyushkina, I.A.</p> <p>1987-10-20</p> <p>The lack of an adequate hydrodynamic model for a hydrocyclone has so far been the main obstacle to devising a general method for designing such apparatus. The authors present a method of calculating the liquid flow in the working zone. The results have been used to calculate the <span class="hlt">separating</span> power in application to dilute suspensions. The Navier-Stokes equations and the equation of continuity are used in examining the behavior together with assumptions based on experiment: the conditions for stationary axisymmetric flow, constant turbulent viscosity, and a constant radial profile for the tangential low speed at all the heights. The boundary conditions are those for liquid slip at the side walls and absence of vortex drainage at the axis. The results enable one to choose the dimensions for particular <span class="hlt">separations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24812740','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24812740"><span>Tooth <span class="hlt">separation</span> potential problems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vishwanath, A E; Sharmada, B K; Pai, Sandesh S; Nandini, Nelvigi; Roopa, Tubaki</p> <p>2014-01-01</p> <p>A displaced orthodontic elastic <span class="hlt">separator</span> was proposed as being the source of a gingival abscess that progresses to severe bone loss and exfoliation in a healthy adolescent patient with sound periodontal status prior to commencement of orthodontic treatment. After one year of undergoing orthodontic treatment, the patient presented with dull pain and mobility in the left upper permanent molar for which there was no apparent etiology. On clinical examination the patient had gingival inflammation, associated with a deep pocket and severe mobility (Grade III) in relation to the same teeth. Radiographic examination ofan Orthopantomogram (OPG) and IntraOral Periapical Radiograph (IOPAR) revealed a chronic periodontal abscess with severe necrosis of the periodontal ligament and severe alveolar bone loss. On curettage it was found that there was orthodontic elastic <span class="hlt">separator</span> which was displaced sub gingivally. Active orthodontic forces were temporarily removed and splinting was done. 6 month follow up showed no mobility and significant improvement of alveolar bone height.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20862139','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20862139"><span>Advanced <span class="hlt">Separation</span> Consortium</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p></p> <p>2006-01-01</p> <p>The Center for Advanced <span class="hlt">Separation</span> Technologies (CAST) was formed in 2001 under the sponsorship of the US Department of Energy to conduct fundamental research in advanced <span class="hlt">separation</span> and to develop technologies that can be used to produce coal and minerals in an efficient and environmentally acceptable manner. The CAST consortium consists of seven universities - Virginia Tech, West Virginia University, University of Kentucky, Montana Tech, University of Utah, University of Nevada-Reno, and New Mexico Tech. The consortium brings together a broad range of expertise to solve problems facing the US coal industry and the mining sector in general. At present, a total of 60 research projects are under way. The article outlines some of these, on topics including innovative dewatering technologies, removal of mercury and other impurities, and modelling of the flotation process. 1 photo.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7138654','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/7138654"><span>Laser isotope <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Robinson, C.P.; Reed, J.J.; Cotter, T.P.; Boyer, K.; Greiner, N.R.</p> <p>1975-11-26</p> <p>A process and apparatus for <span class="hlt">separating</span> isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light is described. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photolysis, photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photolysis, photochemical reaction or photoionization. The process is particularly applicable to the <span class="hlt">separation</span> of isotopes of uranium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5291338','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/5291338"><span>Steam <span class="hlt">separator</span> latch assembly</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Challberg, R.C.; Kobsa, I.R.</p> <p>1994-02-01</p> <p>A latch assembly removably joins a steam <span class="hlt">separator</span> assembly to a support flange disposed at a top end of a tubular shroud in a nuclear reactor pressure vessel. The assembly includes an annular head having a central portion for supporting the steam <span class="hlt">separator</span> assembly thereon, and an annular head flange extending around a perimeter thereof for supporting the head to the support flange. A plurality of latches are circumferentially spaced apart around the head flange with each latch having a top end, a latch hook at a bottom end thereof, and a pivot support disposed at an intermediate portion therebetween and pivotally joined to the head flange. The latches are pivoted about the pivot supports for selectively engaging and disengaging the latch hooks with the support flange for fixedly joining the head to the shroud or for allowing removal thereof. 12 figures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/869145','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/869145"><span>Steam <span class="hlt">separator</span> latch assembly</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Challberg, Roy C.; Kobsa, Irvin R.</p> <p>1994-01-01</p> <p>A latch assembly removably joins a steam <span class="hlt">separator</span> assembly to a support flange disposed at a top end of a tubular shroud in a nuclear reactor pressure vessel. The assembly includes an annular head having a central portion for supporting the steam <span class="hlt">separator</span> assembly thereon, and an annular head flange extending around a perimeter thereof for supporting the head to the support flange. A plurality of latches are circumferentially spaced apart around the head flange with each latch having a top end, a latch hook at a bottom end thereof, and a pivot support disposed at an intermediate portion therebetween and pivotally joined to the head flange. The latches are pivoted about the pivot supports for selectively engaging and disengaging the latch hooks with the support flange for fixedly joining the head to the shroud or for allowing removal thereof.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790013426&hterms=nylon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dnylon','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790013426&hterms=nylon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dnylon"><span>Nylon <span class="hlt">separators</span>. [thermal degradation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lim, H. S.</p> <p>1977-01-01</p> <p>A nylon <span class="hlt">separator</span> was placed in a flooded condition in K0H solution and heated at various high temperatures ranging from 60 C to 110 C. The weight decrease was measured and the molecular weight and decomposition product were analyzed to determine: (1) the effect of K0H concentration on the hydrolysis rate; (2) the effect of K0H concentration on nylon degradation; (3) the activation energy at different K0H concentrations; and (4) the effect of oxygen on nylon degradation. The nylon hydrolysis rate is shown to increase as K0H concentration is decreased 34%, giving a maximum rate at about 16%. <span class="hlt">Separator</span> hydrolysis is confirmed by molecular weight decrease in age of the batteries, and the reaction of nylon with molecular oxygen is probably negligible, compared to hydrolysis. The extrapolated rate value from the high temperature experiment correlates well with experimental values at 35 degrees.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/866547','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/866547"><span>Laser isotope <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Boyer, Keith; Greiner, Norman R.</p> <p>1988-01-01</p> <p>A process and apparatus for <span class="hlt">separating</span> isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photolysis, photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photolysis, photochemical reaction or photoionization. The process is particularly applicable to the <span class="hlt">separation</span> of isotopes of uranium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/866235','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/866235"><span>Photochemical isotope <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Greiner, Norman R.; Boyer, Keith</p> <p>1987-01-01</p> <p>A process for <span class="hlt">separating</span> isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the <span class="hlt">separation</span> of isotopes of uranium and plutonium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4138806','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4138806"><span>METHOD OF <span class="hlt">SEPARATING</span> PLUTONIUM</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Heal, H.G.</p> <p>1960-02-16</p> <p>BS>A method of <span class="hlt">separating</span> plutonium from aqueous nitrate solutions of plutonium, uranium. and high beta activity fission products is given. The pH of the aqueous solution is adjusted between 3.0 to 6.0 with ammonium acetate, ferric nitrate is added, and the solution is heated to 80 to 100 deg C to selectively form a basic ferric plutonium-carrying precipitate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA583712','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA583712"><span>Acromioclavicular Joint <span class="hlt">Separations</span></span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>2013-01-01</p> <p>non-surgical measures, high-grade inju- ries frequently warrant surgical intervention to minimize pain and maximize shoulder function. Factors such as...sports [1–3]. While most injuries can be managed non-operatively, high-grade <span class="hlt">separations</span> may result in per- sistent pain or functional decline and...joint pathology (cross arm adduction and loading of the AC joint) can be helpful to localize shoulder pain to the AC joint. These tests are especial- ly</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA275130','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA275130"><span>Enlisted Administrative <span class="hlt">Separations</span></span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>1993-12-21</p> <p>1 16. Sexual Orientation . A sexual attraction to individuals of a particular sex. 17. Show-Cause Authority. Any of the following as determined by the...homosexual acts is grounds for <span class="hlt">separation</span> not because it reflects the member’s sexual orientation , but because the statement indicates a likelihood that the...member engages in or will engage in homosexual acts. Sexual orientation is considered a personal and private matter, and homosexual orientation is not</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4796849','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4796849"><span>URANIUM <span class="hlt">SEPARATION</span> PROCESS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Lyon, W.L.</p> <p>1962-04-17</p> <p>A method of <span class="hlt">separating</span> uranium oxides from PuO/sub 2/, ThO/sub 2/, and other actinide oxides is described. The oxide mixture is suspended in a fused salt melt and a chlorinating agent such as chlorine gas or phosgene is sparged through the suspension. Uranium oxides are selectively chlorinated and dissolve in the melt, which may then be filtered to remove the unchlorinated oxides of the other actinides. (AEC)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4329929','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4329929"><span><span class="hlt">SEPARATION</span> OF PLUTONYL IONS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Connick, R.E.; McVey, Wm.H.</p> <p>1958-07-15</p> <p>A process is described for <span class="hlt">separating</span> plutonyl ions from the acetate ions with which they are associated in certaln carrier precipitation methods of concentrating plutonium. The method consists in adding alkaline earth metal ions and subsequently alkalizing the solution, causing formation of an alkaltne earth plutonate precipitate. Barium hydroxide is used in a preferred embodiment since it provides alkaline earth metal ion and alkalizes the solution in one step forming insoluble barium platonate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/866016','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/866016"><span>Membrane <span class="hlt">separation</span> of hydrocarbons</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Funk, Edward W.; Kulkarni, Sudhir S.; Chang, Y. Alice</p> <p>1986-01-01</p> <p>Mixtures of heavy oils and light hydrocarbons may be <span class="hlt">separated</span> by passing the mixture over a polymeric membrane which comprises a polymer capable of maintaining its integrity in the presence of hydrocarbon compounds at temperature ranging from about ambient to about 100.degree. C. and pressures ranging from about 50 to about 1000 psi. The membranes which possess pore sizes ranging from about 10 to about 500 Angstroms are cast from a solvent solution and recovered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4207797','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4207797"><span>ISOTOPE <span class="hlt">SEPARATING</span> APPARATUS CONTROL</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Barnes, S.W.</p> <p>1959-08-25</p> <p>An improved isotope <span class="hlt">separating</span> apparatus of the electromagnetic type, commonly referred to as a calutron, is described. Improvements in detecting and maintaining optimum position and focus of the ion beam are given. The calutron collector is provided with an additional electrode insulated from and positioned between the collecting pockets. The ion beams are properly positioned and focused until the deionizing current which flows from ground to this additional electrode ts a minimum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940012889','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940012889"><span>Color <span class="hlt">separation</span> gratings</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farn, Michael W.; Knowlden, Robert E.</p> <p>1993-01-01</p> <p>In this paper, we describe the theory, fabrication and test of a binary optics 'echelon'. The echelon is a grating structure which <span class="hlt">separates</span> electromagnetic radiation of different wavelengths, but it does so according to diffraction order rather than by dispersion within one diffraction order, as is the case with conventional gratings. A prototype echelon, designed for the visible spectrum, is fabricated using the binary optics process. Tests of the prototype show good agreement with theoretical predictions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23546253','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23546253"><span><span class="hlt">Frequency</span> noise in <span class="hlt">frequency</span> swept fiber laser.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pedersen, Anders Tegtmeier; Rottwitt, Karsten</p> <p>2013-04-01</p> <p>This Letter presents a measurement of the spectral content of <span class="hlt">frequency</span> shifted pulses generated by a lightwave synthesized <span class="hlt">frequency</span> sweeper. We found that each pulse is shifted in <span class="hlt">frequency</span> with very high accuracy. We also discovered that noise originating from light leaking through the acousto- optical modulators and forward propagating Brillouin scattering appear in the spectrum.</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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