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. Vocalization frequency and duration are coded in separate hindbrain nuclei

    PubMed Central

    Chagnaud, Boris P.; Baker, Robert; Bass, Andrew H.

    2011-01-01

    Temporal patterning is an essential feature of neural networks producing precisely timed behaviours such as vocalizations that are widely used in vertebrate social communication. Here we show that intrinsic and network properties of separate hindbrain neuronal populations encode the natural call attributes of frequency and duration in vocal fish. Intracellular structure/function analyses indicate that call duration is encoded by a sustained membrane depolarization in vocal prepacemaker neurons that innervate downstream pacemaker neurons. Pacemaker neurons, in turn, encode call frequency by rhythmic, ultrafast oscillations in their membrane potential. Pharmacological manipulations show prepacemaker activity to be independent of pacemaker function, thus accounting for natural variation in duration which is the predominant feature distinguishing call types. Prepacemaker neurons also innervate key hindbrain auditory nuclei thereby effectively serving as a call-duration corollary discharge. We propose that premotor compartmentalization of neurons coding distinct acoustic attributes is a fundamental trait of hindbrain vocal pattern generators among vertebrates. PMID:21673667

  7. Seasonal variations of volcanic eruption frequencies

    NASA Astrophysics Data System (ADS)

    Stothers, Richard B.

    1989-05-01

    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.

  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. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  10. 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.

  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. 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...

  13. 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. 76.612 Section 76.612 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Technical Standards § 76.612 Cable television...

  14. 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.

  15. 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 frequency...

  16. 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....

  17. 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.

  18. 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.

  19. 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

  20. 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...

  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. 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. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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).

  9. 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.

  10. When Does Frequency-Independent Selection Maintain Genetic Variation?

    PubMed

    Novak, Sebastian; Barton, Nicholas H

    2017-10-01

    Frequency-independent selection is generally considered as a force that acts to reduce the genetic variation in evolving populations, yet rigorous arguments for this idea are scarce. When selection fluctuates in time, it is unclear whether frequency-independent selection may maintain genetic polymorphism without invoking additional mechanisms. We show that constant frequency-independent selection with arbitrary epistasis on a well-mixed haploid population eliminates genetic variation if we assume linkage equilibrium between alleles. To this end, we introduce the notion of frequency-independent selection at the level of alleles, which is sufficient to prove our claim and contains the notion of frequency-independent selection on haploids. When selection and recombination are weak but of the same order, there may be strong linkage disequilibrium; numerical calculations show that stable equilibria are highly unlikely. Using the example of a diallelic two-locus model, we then demonstrate that frequency-independent selection that fluctuates in time can maintain stable polymorphism if linkage disequilibrium changes its sign periodically. We put our findings in the context of results from the existing literature and point out those scenarios in which the possible role of frequency-independent selection in maintaining genetic variation remains unclear. Copyright © 2017 by the Genetics Society of America.

  11. Os incae: variation in frequency in major human population groups

    PubMed Central

    HANIHARA, TSUNEHIKO; ISHIDA, HAJIME

    2001-01-01

    The variation in frequency of the Inca bone was examined in major human populations around the world. The New World populations have generally high frequencies of the Inca bone, whereas lower frequencies occur in northeast Asians and Australians. Tibetan/Nepalese and Assam/Sikkim populations in northeast India have more Inca bones than do neighbouring populations. Among modern populations originally derived from eastern Asian population stock, the frequencies are highest in some of the marginal isolated groups. In Central and West Asia as well as in Europe, frequency of the Inca bone is relatively low. The incidence of the complete Inca bone is, moreover, very low in the western hemisphere of the Old World except for Subsaharan Africa. Subsaharan Africans show as a whole a second peak in the occurrence of the Inca bone. Geographical and ethnographical patterns of the frequency variation of the Inca bone found in this study indicate that the possible genetic background for the occurrence of this bone cannot be completely excluded. Relatively high frequencies of the Inca bone in Subsaharan Africans indicate that this trait is not a uniquely eastern Asian regional character. PMID:11273039

  12. The functional spectrum of low-frequency coding variation.

    PubMed

    Marth, Gabor T; Yu, Fuli; Indap, Amit R; Garimella, Kiran; Gravel, Simon; Leong, Wen Fung; Tyler-Smith, Chris; Bainbridge, Matthew; Blackwell, Tom; Zheng-Bradley, Xiangqun; Chen, Yuan; Challis, Danny; Clarke, Laura; Ball, Edward V; Cibulskis, Kristian; Cooper, David N; Fulton, Bob; Hartl, Chris; Koboldt, Dan; Muzny, Donna; Smith, Richard; Sougnez, Carrie; Stewart, Chip; Ward, Alistair; Yu, Jin; Xue, Yali; Altshuler, David; Bustamante, Carlos D; Clark, Andrew G; Daly, Mark; DePristo, Mark; Flicek, Paul; Gabriel, Stacey; Mardis, Elaine; Palotie, Aarno; Gibbs, Richard

    2011-09-14

    Rare coding variants constitute an important class of human genetic variation, but are underrepresented in current databases that are based on small population samples. Recent studies show that variants altering amino acid sequence and protein function are enriched at low variant allele frequency, 2 to 5%, but because of insufficient sample size it is not clear if the same trend holds for rare variants below 1% allele frequency. The 1000 Genomes Exon Pilot Project has collected deep-coverage exon-capture data in roughly 1,000 human genes, for nearly 700 samples. Although medical whole-exome projects are currently afoot, this is still the deepest reported sampling of a large number of human genes with next-generation technologies. According to the goals of the 1000 Genomes Project, we created effective informatics pipelines to process and analyze the data, and discovered 12,758 exonic SNPs, 70% of them novel, and 74% below 1% allele frequency in the seven population samples we examined. Our analysis confirms that coding variants below 1% allele frequency show increased population-specificity and are enriched for functional variants. This study represents a large step toward detecting and interpreting low frequency coding variation, clearly lays out technical steps for effective analysis of DNA capture data, and articulates functional and population properties of this important class of genetic variation.

  13. 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

  14. 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

  15. 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.

  16. 47 CFR 76.612 - Cable television frequency separation standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... signals or signal components carried at an average power level equal to or greater than 10−4 watts in a 25... those frequencies which are within one of the aeronautical bands defined in this subparagraph, and when... and 328.6-335.4 MHz, the frequency of all carrier signals or signal components carrier at an average...

  17. 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%.

  18. 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%.

  19. Microwave photonic system for instantaneous frequency measurement based on principles of "frequency-amplitude" conversion in fiber Bragg grating and additional frequency separation

    NASA Astrophysics Data System (ADS)

    Ivanov, Alexander A.; Morozov, Oleg G.; Andreev, Vladimir A.; Morozov, Gennady A.; Kuznetsov, Artem A.; Faskhutdinov, Lenar M.

    2017-04-01

    This article describes the design principles of optoelectronic system (OES) for instantaneous frequency measurement (IFM) of microwave signals based on the use of amplitude-phase modulation conversion of single optical carrier into symmetrical dual-frequency signal for additional frequency separation, its modulation by unknown frequency and subsequent "frequency-amplitude" measurement conversion in Fiber Bragg Grating (FBG) with Gaussian reflection profile. Such approach allows increasing of measurement resolution at low frequencies.

  20. 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

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

    PubMed

    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.

  2. Radio-frequency ion deflector for mass separation

    SciTech Connect

    Schlösser, Magnus Rudnev, Vitaly; Ureña, Ángel González

    2015-10-15

    Electrostatic cylindrical deflectors act as energy analyzer for ion beams. In this article, we present that by imposing of a radio-frequency modulation on the deflecting electric field, the ion transmission becomes mass dependent. By the choice of the appropriate frequency, amplitude, and phase, the deflector can be used as mass filter. The basic concept of the new instrument as well as simple mathematic relations are described. These calculations and further numerical simulations show that a mass sensitivity is achievable. Furthermore, we demonstrate the proof-of-principle in experimental measurements, compare the results to those of from a 1 m linear time-of-flight spectrometer, and comment on the mass resolution of the method. Finally, some potential applications are indicated.

  3. 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.

  4. p-mode frequency variation in relation to global solar activity

    NASA Technical Reports Server (NTRS)

    Bachmann, Kurt T.; Brown, Timothy M.

    1993-01-01

    We show that p-mode frequency variations correlate remarkably well with the variations of six solar activity indices over a 6 yr period from 1984 October to 1990 November, including both the large variation from solar minimum to solar maximum and smaller variations observed over approximately 1 month intervals during solar maximum. The quality of correlation as seen visually and as measured by two statistical tests differs significantly among the six activity indices, and we briefly speculate on possible reasons for this. Observations used in this study come from the HAO/NSO Fourier tachometer (FTACH) and include the spherical harmonic degree range l greater than 20 and equal to 60 or less and frequency range between 2600 and 3200 micro-Hz. The data are divided into 18 separate epochs with time string duration ranging from a minimum of 18 days to a maximum of 45 days. We have particularly good coverage during the early part of solar maximum of cycle 22.

  5. 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.

  6. 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

    2017-08-01

    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.

  7. 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.

  8. Separation of variations of the geomagnetic field into normal and anomalous parts on a bounded territory

    NASA Astrophysics Data System (ADS)

    Zhdanov, M. S.; Plotnikov, S. V.

    1981-12-01

    A method based on convolution integrals is developed for separating geomagnetic variations into normal and anomalous parts. It is shown for a number of typical models of normal geoelectric section that the kernels of the integral transforms have the form of spatial windows which fluctuate (depending on the variation period) from several tens to several hundreds of kilometers. This indicates the possibility of separating fields specified on a bounded territory into normal and anomalous parts.

  9. 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.

  10. Frequency variations of discrete cranial traits in major human populations. II. Hypostotic variations

    PubMed Central

    HANIHARA, TSUNEHIKO; ISHIDA, HAJIME

    2001-01-01

    Five discrete hypostotic cranial traits, tympanic dehiscence, ovale-spinosum confluence, metopism, transverse zygomatic suture vestige, and biasterionic suture, were investigated in 81 human population samples. Except for ovale-spinosum confluence, marked asymmetric occurrences of the bilateral traits were not detected in the majority of the samples. Significant intertrait association was observed mainly between the biasterionic suture and other sutural variations including accessory ossicles. The traits showing relatively consistent sex differences across diverse populations were tympanic dehiscence, which is predominant in females, and biasterionic suture in males. On a world scale, the 5 hypostotic cranial traits showed distinctive patterns of geographical variation. Different clinal variations within and between macrogeographical areas such as western and eastern parts of the Old World were found for the frequencies of the traits. The Ainu may be the most distinct outlier in the eastern Asian region on the basis of the incidence of the traits, especially the transverse zygomatic suture vestige. The interregional variation without reasonable adaptive value and nonadaptive shift of the possible outliers presented in this study suggest that the genetic background for the occurrence of these traits cannot be excluded completely. PMID:11465863

  11. 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.

  12. 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.

  13. 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}.

  14. 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.

  15. 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.

  16. Spatial pattern separation of chemicals and frequency-independent components by terahertz spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Watanabe, Yuuki; Kawase, Kodo; Ikari, Tomofumi; Ito, Hiromasa; Ishikawa, Youichi; Minamide, Hiroaki

    2003-10-01

    We separated the component spatial patterns of frequency-dependent absorption in chemicals and frequency-independent components such as plastic, paper, and measurement noise in terahertz (THz) spectroscopic images, using known spectral curves. Our measurement system, which uses a widely tunable coherent THz-wave parametric oscillator source, can image at a specific frequency in the range 1-2 THz. The component patterns of chemicals can easily be extracted by use of the frequency-independent components. This method could be successfully used for nondestructive inspection for the detection of illegal drugs and devices of bioterrorism concealed, e.g., inside mail and packages.

  17. 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

  18. 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

  19. High-performance radio frequency transistors based on diameter-separated semiconducting carbon nanotubes

    SciTech Connect

    Cao, Yu; Che, Yuchi; Zhou, Chongwu; Seo, Jung-Woo T.; Hersam, Mark C.; Gui, Hui

    2016-06-06

    In this paper, we report the high-performance radio-frequency transistors based on the single-walled semiconducting carbon nanotubes with a refined average diameter of ∼1.6 nm. These diameter-separated carbon nanotube transistors show excellent transconductance of 55 μS/μm and desirable drain current saturation with an output resistance of ∼100 KΩ μm. An exceptional radio-frequency performance is also achieved with current gain and power gain cut-off frequencies of 23 GHz and 20 GHz (extrinsic) and 65 GHz and 35 GHz (intrinsic), respectively. These radio-frequency metrics are among the highest reported for the carbon nanotube thin-film transistors. This study provides demonstration of radio frequency transistors based on carbon nanotubes with tailored diameter distributions, which will guide the future application of carbon nanotubes in radio-frequency electronics.

  20. 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.

  1. 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.

  2. How to separate the low amplitude delta Scuti variation in CoRoT data unambigousely?

    NASA Astrophysics Data System (ADS)

    Benko, Jozsef M.; Paparo, Margit

    2015-08-01

    Rich regular frequency patterns were found in the Fourier spectra of low-amplitude Delta Scuti stars observed by CoRoT satellite. The CoRoT observations are, however, influenced by the disturbing effect of the SAA. The effect is marginal for high amplitude variable stars but it could be dangerous in the case of low amplitude variables, especially if the frequency range of the intrinsic variation overlaps the instrumental frequencies. Systematic tests were carried out both on synthetic and real data. Our aim was to determine a limit amplitude above which we were sure that the frequency pattern belonged to the stars.

  3. 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

  4. 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…

  5. 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…

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Instantaneous and Frequency-Warped Signal Processing Techniques for Auditory Source Separation.

    NASA Astrophysics Data System (ADS)

    Wang, Avery Li-Chun

    This thesis summarizes several contributions to the areas of signal processing and auditory source separation. The philosophy of Frequency-Warped Signal Processing is introduced as a means for separating the AM and FM contributions to the bandwidth of a complex-valued, frequency-varying sinusoid p (n), transforming it into a signal with slowly-varying parameters. This transformation facilitates the removal of p (n) from an additive mixture while minimizing the amount of damage done to other signal components. The average winding rate of a complex-valued phasor is explored as an estimate of the instantaneous frequency. Theorems are provided showing the robustness of this measure. To implement frequency tracking, a Frequency-Locked Loop algorithm is introduced which uses the complex winding error to update its frequency estimate. The input signal is dynamically demodulated and filtered to extract the envelope. This envelope may then be remodulated to reconstruct the target partial, which may be subtracted from the original signal mixture to yield a new, quickly-adapting form of notch filtering. Enhancements to the basic tracker are made which, under certain conditions, attain the Cramer -Rao bound for the instantaneous frequency estimate. To improve tracking, the novel idea of Harmonic -Locked Loop tracking, using N harmonically constrained trackers, is introduced for tracking signals, such as voices and certain musical instruments. The estimated fundamental frequency is computed from a maximum-likelihood weighting of the N tracking estimates, making it highly robust. The result is that harmonic signals, such as voices, can be isolated from complex mixtures in the presence of other spectrally overlapping signals. Additionally, since phase information is preserved, the resynthesized harmonic signals may be removed from the original mixtures with relatively little damage to the residual signal. Finally, a new methodology is given for designing linear-phase FIR filters

  16. Separate recording of rationally related vibration frequencies using digital stroboscopic holographic interferometry

    SciTech Connect

    Alexeenko, Igor; Gusev, Michael; Gurevich, Vadim

    2009-06-20

    A method for separate recording of rationally related vibration frequencies is presented. To record and measure the mode shape of vibrations, a synchronized stroboscopic CCD camera is used. Synchronization and control of the camera acquisition for recording stroboscopic holographic sequence has been realized. The phase for different states of the object vibration is calculated using the Fourier-transform method. Experimental results are presented, and the advantages and disadvantages of the proposed method are discussed.

  17. Variation in optineurin (OPTN) allele frequencies between and within populations

    PubMed Central

    Ayala-Lugo, Rosa M.; Pawar, Hemant; Reed, David M.; Lichter, Paul R.; Moroi, Sayoko E.; Page, Michael; Eadie, James; Azocar, Veronica; Maul, Eugenio; Ntim-Amponsah, Christine; Bromley, William; Obeng-Nyarkoh, Ebenezer; Johnson, A. Tim; Kijek, Theresa Guckian; Downs, Catherine A.; Johnson, Jenae M.; Perez-Grossmann, Rodolfo A.; Guevara-Fujita, Maria-Luisa; Fujita, Ricardo; Wallace, Margaret R.

    2007-01-01

    Purpose To evaluate the extent to which mutations in the optineurin (OPTN) glaucoma gene play a role in glaucoma in different populations. Methods Case-controlled study of OPTN sequence variants in individuals with or without glaucoma in populations of different ancestral origins and evaluate previous OPTN reports. We analyzed 314 subjects with African, Asian, Caucasian and Hispanic ancestries included 229 cases of primary open-angle glaucoma, 51 cases of juvenile-onset open-angle glaucoma, 33 cases of normal tension glaucoma, and 371 controls. Polymerase chain reaction-amplified OPTN coding exons were resequenced and case frequencies were compared to frequencies in controls matched for ancestry. Results The E50K sequence variant was identified in one individual from Chile with normal tension glaucoma, and the 691_692insAG variant was found in one Ashkenazi Jewish individual from Russia. The R545Q variant was found in two Asian individuals with primary open-angle glaucoma; one of Filipino ancestry and one of Korean ancestry. In addition to presenting OPTN allele frequencies for Caucasian and Asian populations that have been the subject of previous reports, we also present information for populations of Hispanic and black African ancestries. Conclusions Our study contributes additional evidence to support the previously reported association of the OPTN E50K mutation with glaucoma. After finding an additional 691_692insAG OPTN variant, we can still only conclude that this variant is rare. Combined analysis of our data with data from more than a dozen other studies indicates no association of R545Q with glaucoma in most populations. Those same studies disagree in their conclusions regarding the role of M98K in glaucoma. Our analysis of the combined data provides statistically significant evidence of association of M98K with normal tension glaucoma in Asian populations, but not in Caucasian populations; however, the validity of this conclusion is questionable because

  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. Variation of acoustic mode centroid frequencies over the solar cycle

    NASA Astrophysics Data System (ADS)

    Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; Isaak, G. R.; New, R.

    Together with a brief historical overview, we use high-quality helioseismic data collected by three different observational programmes during the declining phase of activity cycle 22, and a substantial portion of the rising phase of the current cycle (23), to study the phenomenological nature of the cycle-induced (centroid) eigenfrequencies. Our analyses (for 1600 ≤ ν ≤ 4000 μHz) make use of observations made by the ground-based GONG over the angular degree range 4 ≤ l ≤ 150; the ground-based BiSON over 0 ≤ l ≤ 2; and the VIRGO/LOI instrument on board the ESA/NASA SOHO satellite over 0 ≤ l ≤ 8. We show that GONG shifts averaged over different ranges in l, together with the BiSON and LOI data averaged over their full quoted ranges, all scale at a given frequency with the normalized mode inertia ratio Qnl (Christensen-Dalsgaard & Berthomieu 1991). This is to be expected if the time-dependent perturbation affecting the modes is confined in the surface layers; the excellent agreement also reflects favourably on the external consistency of the different observations. We have also analyzed the frequency dependence of the shifts by fitting a power-law of the form δν nl ∝ (ν nl/ Enl to the data (where the Enl are the mode inertias, and α is the power-law index to be extracted). Previous studies have suggested that a relation with α = 0 provides an adequate description of the shifts up to ν ≈ 3500 μHz. However, here we show that while nevertheless describing the shifts well up to ˜ 2500 μHz, the linear scaling breaks down conspicuously at higher frequencies. Above this threshold, the shifts follow a power-law dependence with α ˜ 2.

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. 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%.

  5. 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

  6. 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

  7. International Deep Planet Survey, 317 stars to determine the wide-separated planet frequency

    NASA Astrophysics Data System (ADS)

    Galicher, R.; Marois, C.; Macintosh, B.; Zuckerman, B.; Song, I.; Barman, T.; Patience, J.

    2013-09-01

    Since 2000, more than 300 nearby young stars were observed for the International Deep Planet Survey with adaptive optics systems at Gemini (NIRI/NICI), Keck (Nirc2), and VLT (Naco). Massive young AF stars were included in our sample whereas they have generally been neglected in first generation surveys because the contrast and target distances are less favorable to image substellar companions. The most significant discovery of the campaign is the now well-known HR 8799 multi-planet system. This remarkable finding allows, for the first time, an estimate of the Jovians planet population at large separations (further than a few AUs) instead of deriving upper limits. During my presentation, I will present the survey showing images of multiple stars and planets. I will then propose a statistic study of the observed stars deriving constraints on the Jupiter-like planet frequency at large separations.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2981126','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2981126"><span><span class="hlt">Variation</span> in the resting <span class="hlt">frequency</span> of Rhinolophus pusillus in Mainland China: Effect of climate and implications for conservation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jiang, Tinglei; Metzner, Walter; You, Yuyan; Liu, Sen; Lu, Guanjun; Li, Shi; Wang, Lei; Feng, Jiang</p> <p>2010-01-01</p> <p>This study describes <span class="hlt">variation</span> patterns in the constant <span class="hlt">frequency</span> 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 <span class="hlt">variation</span> 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 <span class="hlt">frequencies</span> within a narrow range for sex recognition. Moreover, bats adjusted resting <span class="hlt">frequency</span> to humidity, which may imply partitioning diet by prey size or the influence of rainfall noise. The results indicate that bats adjust echolocation call <span class="hlt">frequency</span> to adapt to environmental conditions. Therefore, environmental selection shape the diversity of echolocation call structure of R. pusillus in geographically <span class="hlt">separated</span> populations, and conservation efforts should focus on changes in local climate and effects of environmental noise. PMID:20968390</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> <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> </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('https://www.ncbi.nlm.nih.gov/pubmed/26058245','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26058245"><span><span class="hlt">Frequency</span> of radial artery anatomic <span class="hlt">variations</span> in patients undergoing transradial heart catheterization.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ostojić, Zvonimir; Bulum, Joško; Ernst, Aleksander; Strozzi, Maja; Marić-Bešić, Kristina</p> <p>2015-03-01</p> <p>Over the last ten years, transradial cardiac catheterization has been increasingly applied, primarily because of its lower incidence of complications compared to the femoral approach. However, one of the greatest flaws of the transradial approach is a relatively high incidence of catheterization failure (1%-5%). Anatomic <span class="hlt">variations</span> of radial artery are ranked second among the reasons for this. Previous studies have not provided unambiguous data on the <span class="hlt">frequency</span> of these anomalies. It was therefore the aim of this study to determine the <span class="hlt">frequency</span> of anatomic <span class="hlt">variations</span> using routine angiographies of radial artery during left heart catheterization. This was a retrospective study involving examination of 602 images of routine angiographies of radial artery performed during cardiac catheterization. The <span class="hlt">frequency</span> of anatomic <span class="hlt">variations</span> of radial artery was 8.8%, exclusive of tortuosities with a <span class="hlt">frequency</span> of 12.7%. The most frequent anatomic <span class="hlt">variation</span> was the high origin of radial artery, found in 31 (5.1%) subjects. Radioulnar loops, being one of the potential contraindications for the procedure, were reported in 2% of cases. Regression analysis revealed that age (p < 0.001), female sex (p = 0.015) and high origin (p = 0.034) considerably contributed to the development of tortuosity. The results indicated the incidence of tortuosity to increase linearly with age. Although it is not a contraindication for continuing with the procedure, we recommend that elderly patients have angiography of radial artery performed at the beginning of the procedure due to the higher <span class="hlt">frequency</span> of tortuosity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E.202B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E.202B"><span>Analysis of the <span class="hlt">variation</span> of Hurricane <span class="hlt">frequency</span> over Atlantic region during 1851-2010</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Banerjee, Dhruba; Bondyopadhaya, Ramaprosad</p> <p></p> <p>Analysis of the <span class="hlt">variation</span> of Hurricane <span class="hlt">frequency</span> over Atlantic region during 1851-2010 The <span class="hlt">variation</span> of number of Hurricane over Atlantic and East Caribbean region during more than 150 years (1851-2010) have been analyzed. The general observations regarding characteristics are (ref{GrindEQ__1_}) the <span class="hlt">frequency</span> increases monotonically, (ref{GrindEQ__2_}) the monthly <span class="hlt">variation</span> of the <span class="hlt">frequencies</span> also exists and the <span class="hlt">frequency</span> of Hurricanes are much more during August to October, September being the month of maximum hurricane nearly 3.2 per year. Reverse is the situation during December to June. If we note the 30 years <span class="hlt">variation</span> of Hurricane <span class="hlt">frequency</span> we find 1941-1970 and 1971-2000 are two spans of years when total Hurricane number over Atlantic region was maximum. When we analyze these rates of increase we find this rate is monotonically increasing from 1851upto1910 but after that it begins to drop slowly. The maximum rate was 1.22 per yr.(roughly).In recent decade during 1971-2010, actually decadal analysis shows that it was less than 10 before1991 but more than 10 after that time and during 2001-10 it was 13.3. Another very important observation is that while the average <span class="hlt">frequency</span> of hurricane over the period 1851-2010 is 8.8, the average <span class="hlt">frequency</span> during solar maxima years is 8.3but the said <span class="hlt">frequency</span> during solar minima is 9.53.This is very significant. Because this implies that solar influence must have negative effect on Hurricane formation. We may note that similar situation prevail for the formation of tropical cyclone like 1957. In fact, in many solar maximum years Hurricane does not form over Atlantic and East Caribbean region. On the contrary many deadliest hurricanes over USA occurred in solar minima years or in the neighborhood. Finally it is outlined the possible mechanism due to which solar activities may decrease the formation of hurricane. It may be worth noting that the nature <span class="hlt">variation</span> of solar phase/cycle is more predictable than the hurricane</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('http://adsabs.harvard.edu/abs/2017MeScT..28g5004G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MeScT..28g5004G"><span>Mode <span class="hlt">separation</span> in <span class="hlt">frequency</span>-wavenumber domain through compressed sensing of far-field Lamb waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Fei; Zeng, Liang; Lin, Jing; Luo, Zhi</p> <p>2017-07-01</p> <p>This method based on Lamb waves shows great potential for long-range damage detection. Mode superposition resulting from multi-modal and dispersive characteristics makes signal interpretation and damage feature extraction difficult. Mode <span class="hlt">separation</span> in the <span class="hlt">frequency</span>-wavenumber (f-k) domain using a 1D sparse sensing array is a promising solution. However, due to the lack of prior knowledge about damage location, this method based on 1D linear measurement, for the mode extraction of arbitrary reflections caused by defects that are not in line with the sensor array, is restricted. In this paper, an improved compressed sensing method under the far-field assumption is established, which is beneficial to the reconstruction of reflections in the f-k domain. Hence, multiple components consisting of structure and damage features could be recovered via a limited number of measurements. Subsequently, a mode sweeping process based on theoretical dispersion curves has been designed for mode characterization and direction of arrival estimation. Moreover, 2D f-k filtering and inverse transforms are applied to the reconstructed f-k distribution in order to extract the purified mode of interest. As a result, overlapping waveforms can be <span class="hlt">separated</span> and the direction of defects can be estimated. A uniform linear sensor array consisting of 16 laser excitations is finally employed for experimental investigations and the results demonstrate the efficiency of the proposed method.</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.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('https://www.osti.gov/scitech/biblio/21466900','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21466900"><span>The effect of secondary electrons on the <span class="hlt">separate</span> control of ion energy and flux in dual-<span class="hlt">frequency</span> capacitively coupled radio <span class="hlt">frequency</span> discharges</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Donko, Z.; Hartmann, P.; Korolov, I.; Schulze, J.; Czarnetzki, U.; Schuengel, E.</p> <p>2010-08-23</p> <p>Dual-<span class="hlt">frequency</span> capacitive discharges are used to <span class="hlt">separately</span> control the mean ion energy, {epsilon}{sub ion}, and flux, {Gamma}{sub ion}, at the electrodes. We study the effect of secondary electrons on this <span class="hlt">separate</span> control in argon discharges driven at 2+27 MHz at different pressures using Particle in Cell simulations. For secondary yield {gamma}{approx_equal}0, {Gamma}{sub ion} decreases as a function of the low <span class="hlt">frequency</span> voltage amplitude due to the <span class="hlt">frequency</span> coupling, while it increases at high {gamma} due to the effective multiplication of secondary electrons inside the sheaths. Therefore, <span class="hlt">separate</span> control is strongly limited. {epsilon}{sub ion} increases with {gamma}, which might allow an in situ determination of {gamma}-coefficients.</p> </li> <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://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://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('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=kirchhoff&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dkirchhoff','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850054906&hterms=kirchhoff&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dkirchhoff"><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('https://ntrs.nasa.gov/search.jsp?R=19850054906&hterms=bird+behavior&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbird%2Bbehavior','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850054906&hterms=bird+behavior&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbird%2Bbehavior"><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://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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4549240','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4549240"><span>Extended high-<span class="hlt">frequency</span> bandwidth improves reception of speech in spatially <span class="hlt">separated</span> masking speech</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Levy, Suzanne Carr; Freed, Daniel J.; Nilsson, Michael; Moore, Brian C.J.; Puria, Sunil</p> <p>2015-01-01</p> <p>Objectives The hypothesis that extending the audible <span class="hlt">frequency</span> bandwidth beyond the range currently implemented in most hearing aids can improve speech understanding was tested for normal-hearing and hearing-impaired participants using target sentences and spatially <span class="hlt">separated</span> masking speech. Design The Hearing in Noise Test (HINT) speech corpus was re-recorded and four masking talkers were recorded at a sample rate of 44.1 kHz. All talkers were male native speakers of American English. Reception threshold for Sentences (RTS) were measured in two spatial configurations. In the asymmetric configuration, the target was presented from −45° azimuth and two colocated masking talkers were presented from +45° azimuth. In the diffuse configuration, the target was presented from 0° azimuth and four masking talkers were each presented from a different azimuth: +45°, +135°, −135°, and −45°. The new speech sentences, masking materials and configurations, collectively termed the ‘Hearing in Speech Test (HIST)’, were presented using lowpass filter cutoff <span class="hlt">frequencies</span> of 4, 6, 8, and 10 kHz. For the normal-hearing participants, stimuli were presented in the sound field using loudspeakers. For the hearing-impaired participants, the spatial configurations were simulated using earphones, and a multi-band wide dynamic range compressor with a modified CAM2 fitting algorithm was used to compensate for each participant’s hearing loss. Results For the normal-hearing participants (N=24, mean age 40 years), the RTS improved significantly by 3.0 dB when the bandwidth was increased from 4 to 10 kHz, and a significant improvement of 1.3 dB was obtained from extending the bandwidth from 6 to 10 kHz, in both spatial configurations. Hearing-impaired participants (N=25, mean age 71 years) also showed a significant improvement in RTS with extended bandwidth, but the effect was smaller than for the normal-hearing participants. The mean decrease in RTS when the bandwidth was</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AASP....5...21P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AASP....5...21P"><span>High-<span class="hlt">frequency</span> <span class="hlt">variations</span> of hydrogen spectral lines in the B3V star η UMa</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pokhvala, S. M.</p> <p>2015-09-01</p> <p>We reported the detection of high-<span class="hlt">frequency</span> <span class="hlt">variations</span> in the hydrogen Balmer lines in the hot star η UMa of spectral class B3V. Spectral observations of η UMa were carried out with slitless spectrograph (R˜100) installed on the 60 cm Carl Zeiss telescope in the Andrushivka Observatory. Spectra were obtained with a time resolution in the sub-second range. It has been found that the η UMa shows rapid <span class="hlt">variations</span> in the hydrogen lines Hα, Hβ, Hγ, as well as <span class="hlt">variations</span> in the atmospheric oxygen lines. The intensity <span class="hlt">variations</span> in the hydrogen lines varies from 0.2% to 0.5% , and that of the oxygen lines is approximately 2%.</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('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> </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('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('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('https://www.ncbi.nlm.nih.gov/pubmed/25828030','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25828030"><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="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yeh, Chien-Wei; Blamires, Sean J; Liao, Chen-Pan; Tso, I-Min</p> <p>2015-03-30</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.</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.osti.gov/scitech/biblio/22622203','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22622203"><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://www.osti.gov/scitech">SciTech Connect</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('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('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.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> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26193029','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26193029"><span>External cavity diode laser with <span class="hlt">frequency</span> drift following natural <span class="hlt">variation</span> in air pressure.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Takamizawa, Akifumi; Yanagimachi, Shinya; Ikegami, Takeshi; Kawabata, Ryuzo</p> <p>2015-06-20</p> <p>A compact and mechanically very robust external cavity diode laser was made by removing any position adjusters such as precision screws and piezo actuators, taking advantage of a cat's eye retroreflector insensitive to misalignment. Under free-running operation during 150 h, the <span class="hlt">frequency</span> drift followed natural <span class="hlt">variation</span> in air pressure with a ratio of -66.6±0.1  MHz/hPa in a range between 1001.5 and 1013.6 hPa. The ratio was in good agreement with that estimated from <span class="hlt">variation</span> in the effective cavity length derived from the relation between the pressure and the refractive index of air. These results indicate that an external cavity diode laser with predictable <span class="hlt">frequency</span> drift was successfully created.</p> </li> <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/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.ncbi.nlm.nih.gov/pubmed/8400690','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/8400690"><span>Genetic <span class="hlt">variation</span> among the Mapuche Indians from the Patagonian region of Argentina: mitochondrial DNA sequence <span class="hlt">variation</span> and allele <span class="hlt">frequencies</span> of several nuclear genes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ginther, C; Corach, D; Penacino, G A; Rey, J A; Carnese, F R; Hutz, M H; Anderson, A; Just, J; Salzano, F M; King, M C</p> <p>1993-01-01</p> <p>DNA samples from 60 Mapuche Indians, representing 39 maternal lineages, were genetically characterized for (1) nucleotide sequences of the mtDNA control region; (2) presence or absence of a nine base duplication in mtDNA region V; (3) HLA loci DRB1 and DQA1; (4) <span class="hlt">variation</span> at three nuclear genes with short tandem repeats; and (5) <span class="hlt">variation</span> at the polymorphic marker D2S44. The genetic profile of the Mapuche population was compared to other Amerinds and to worldwide populations. Two highly polymorphic portions of the mtDNA control region, comprising 650 nucleotides, were amplified by the polymerase chain reaction (PCR) and directly sequenced. The 39 maternal lineages were defined by two or three generation families identified by the Mapuches. These 39 lineages included 19 different mtDNA sequences that could be grouped into four classes. The same classes of sequences appear in other Amerinds from North, Central, and South American populations <span class="hlt">separated</span> by thousands of miles, suggesting that the origin of the mtDNA patterns predates the migration to the Americas. The mtDNA sequence similarity between Amerind populations suggests that the migration throughout the Americas occurred rapidly relative to the mtDNA mutation rate. HLA DRB1 alleles 1602 and 1402 were frequent among the Mapuches. These alleles also occur at high <span class="hlt">frequency</span> among other Amerinds in North and South America, but not among Spanish, Chinese or African-American populations. The high <span class="hlt">frequency</span> of these alleles throughout the Americas, and their specificity to the Americas, supports the hypothesis that Mapuches and other Amerind groups are closely related.(ABSTRACT TRUNCATED AT 250 WORDS)</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/2017JAMES...9....4V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JAMES...9....4V"><span><span class="hlt">Variations</span> in tropical cyclone <span class="hlt">frequency</span> response to solar and CO2 forcing in aquaplanet simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Viale, Flora; Merlis, Timothy M.</p> <p>2017-03-01</p> <p>The response of global tropical cyclone (TC) <span class="hlt">frequency</span> to solar and carbon dioxide radiative forcing is examined in TC-permitting aquaplanet general circulation model simulations. With an energetically consistent slab ocean lower boundary condition, the simulations show a larger response to positive radiative forcing from increased carbon dioxide than a solar constant increase with a comparable global-mean radiative forcing. Prescribed sea surface temperature (SST) simulations reveal that both the direct response to radiative forcing (radiative forcing with unchanged SST) and the patterned-SST response vary between forcing agents. The forcing-agent dependence of the patterned-SST response of TC <span class="hlt">frequency</span> can be accounted for by the <span class="hlt">variation</span> in simulated intertropical convergence zone shifts. The forcing-agent dependence of the direct response of TC <span class="hlt">frequency</span> to radiative forcing can be accounted for by the <span class="hlt">variation</span> in direct circulation changes and in normalized moist static energy deficit changes. That the direct TC response differs across forcing agents suggests that solar radiation manipulation geoengineering schemes will not return TC <span class="hlt">frequency</span> to that of an unperturbed climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25095269','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25095269"><span>Denoising of Ictal EEG Data Using Semi-Blind Source <span class="hlt">Separation</span> Methods Based on Time-<span class="hlt">Frequency</span> Priors.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hajipour Sardouie, Sepideh; Bagher Shamsollahi, Mohammad; Albera, Laurent; Merlet, Isabelle</p> <p>2015-05-01</p> <p>Removing muscle activity from ictal ElectroEncephaloGram (EEG) data is an essential preprocessing step in diagnosis and study of epileptic disorders. Indeed, at the very beginning of seizures, ictal EEG has a low amplitude and its morphology in the time domain is quite similar to muscular activity. Contrary to the time domain, ictal signals have specific characteristics in the time-<span class="hlt">frequency</span> domain. In this paper, we use the time-<span class="hlt">frequency</span> signature of ictal discharges as a priori information on the sources of interest. To extract the time-<span class="hlt">frequency</span> signature of ictal sources, we use the Canonical Correlation Analysis (CCA) method. Then, we propose two time-<span class="hlt">frequency</span> based semi-blind source <span class="hlt">separation</span> approaches, namely the Time-<span class="hlt">Frequency</span>-Generalized EigenValue Decomposition (TF-GEVD) and the Time-<span class="hlt">Frequency</span>-Denoising Source <span class="hlt">Separation</span> (TF-DSS), for the denoising of ictal signals based on these time-<span class="hlt">frequency</span> signatures. The performance of the proposed methods is compared with that of CCA and Independent Component Analysis (ICA) approaches for the denoising of simulated ictal EEGs and of real ictal data. The results show the superiority of the proposed methods in comparison with CCA and ICA.</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> </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.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('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('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('https://www.ncbi.nlm.nih.gov/pubmed/22607811','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22607811"><span>Intraspecific <span class="hlt">variations</span> of Dekkera/Brettanomyces bruxellensis genome studied by capillary electrophoresis <span class="hlt">separation</span> of the intron splice site profiles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vigentini, Ileana; De Lorenzis, Gabriella; Picozzi, Claudia; Imazio, Serena; Merico, Annamaria; Galafassi, Silvia; Piškur, Jure; Foschino, Roberto</p> <p>2012-06-15</p> <p>In enology, "Brett" character refers to the wine spoilage caused by the yeast Dekkera/Brettanomyces bruxellensis and its production of volatile phenolic off-flavours. However, the spoilage potential of this yeast is strain-dependent. Therefore, a rapid and reliable recognition at the strain level is a key point to avoid serious economic losses. The present work provides an operative tool to assess the genetic intraspecific <span class="hlt">variation</span> in this species through the use of introns as molecular targets. Firstly, the available partial D./B. bruxellensis genome sequence was investigated in order to build primers annealing to introns 5' splice site sequence (ISS). This analysis allowed the detection of a non-random vocabulary flanking the site and, exploiting this feature, the creation of specific probes for strain discrimination. Secondly, the <span class="hlt">separation</span> of the intron splice site PCR fragments was obtained throughout the set up of a capillary electrophoresis protocol, giving a 94% repeatability threshold in our experimental conditions. The comparison of results obtained with ISS-PCR/CE versus the ones performed by mtDNA RFLP revealed that the former protocol is more discriminating and allowed a reliable identification at strain level. Actually sixty D./B. bruxellensis isolates were recognised as unique strains, showing a level of similarity below 79% and confirming the high genetic polymorphism existing within the species. Two main clusters were grouped at similarity levels of about 46% and 47%, respectively, showing a poor correlation with the geographic area of isolation. Moreover, from the evolutionary point of view, the proposed technique could determine the <span class="hlt">frequency</span> of the genome rearrangements that can occur in D./B. bruxellesis populations. Copyright © 2012 Elsevier B.V. All rights reserved.</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.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('https://www.ncbi.nlm.nih.gov/pubmed/27661929','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27661929"><span>Origin of terminal voltage <span class="hlt">variations</span> due to self-mixing in terahertz <span class="hlt">frequency</span> quantum cascade lasers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Grier, Andrew; Dean, Paul; Valavanis, Alexander; Keeley, James; Kundu, Iman; Cooper, Jonathan D; Agnew, Gary; Taimre, Thomas; Lim, Yah Leng; Bertling, Karl; Rakić, Aleksandar D; Li, Lianhe H; Harrison, Paul; Linfield, Edmund H; Ikonić, Zoran; Davies, A Giles; Indjin, Dragan</p> <p>2016-09-19</p> <p>We explain the origin of voltage <span class="hlt">variations</span> due to self-mixing in a terahertz (THz) <span class="hlt">frequency</span> quantum cascade laser (QCL) using an extended density matrix (DM) approach. Our DM model allows calculation of both the current-voltage (I-V) and optical power characteristics of the QCL under optical feedback by changing the cavity loss, to which the gain of the active region is clamped. The <span class="hlt">variation</span> of intra-cavity field strength necessary to achieve gain clamping, and the corresponding change in bias required to maintain a constant current density through the heterostructure is then calculated. Strong enhancement of the self-mixing voltage signal due to non-linearity of the (I-V) characteristics is predicted and confirmed experimentally in an exemplar 2.6 THz bound-to-continuum QCL.</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('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('https://www.ncbi.nlm.nih.gov/pubmed/11518172','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11518172"><span><span class="hlt">Frequency</span> of nonspecific clinical signs in dogs with <span class="hlt">separation</span> anxiety, thunderstorm phobia, and noise phobia, alone or in combination.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Overall, K L; Dunham, A E; Frank, D</p> <p>2001-08-15</p> <p>To determine the <span class="hlt">frequency</span> of nonspecific clinical signs in dogs with <span class="hlt">separation</span> anxiety, thunderstorm phobia, noise phobia, or any combination of these conditions and determine whether these conditions are associated in dogs. Case series. 141 dogs. Diagnoses were established using specific criteria. Owners of dogs completed a questionnaire on how frequently their dogs exhibited destructive behavior, urination, defecation, vocalization, and salivation when the owners were absent and the types and <span class="hlt">frequency</span> of reactions to thunderstorms, fireworks, and other noises. Associations of the 3 conditions and of various nonspecific clinical signs within and between diagnoses were nonrandom. The probability that a dog would have <span class="hlt">separation</span> anxiety given that it had noise phobia was high (0.88) and approximately the same as the probability it would have <span class="hlt">separation</span> anxiety given that it had thunderstorm phobia (0.86). However, the probability that a dog would have noise phobia given that it had <span class="hlt">separation</span> anxiety (0.63) was higher than the probability that it would have thunderstorm phobia given that it had <span class="hlt">separation</span> anxiety (0.52). The probability that a dog would have noise phobia given that it had thunderstorm phobia (0.90) was not equivalent to the converse (0.76). Results suggested that dogs with any of these conditions should be screened for the others. Interactions among these conditions are important in the assessment and treatment of dogs with > 1 of these conditions. Responses to noise were different from those to thunderstorms, possibly because of the unpredictability and uncertainty of thunderstorms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/14504947','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/14504947"><span>Effect of push <span class="hlt">frequency</span> and strategy <span class="hlt">variations</span> on economy and perceived exertion during wheelchair propulsion.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Goosey-Tolfrey, Victoria Louise; Kirk, Jennifer Helen</p> <p>2003-09-01</p> <p>Wheelchair locomotion is a cyclical activity and participants are free to select any push <span class="hlt">frequency</span>-propulsion strategy combination that suits their needs at a given power output. The aim of the study was to examine the physiological effects of varying push <span class="hlt">frequency</span> and strategy on pushing economy. Twelve male, able-bodied participants completed four, randomly assigned, 5-min bouts of submaximal exercise at 32 W on a wheelchair ergometer. Each bout of exercise combined two different push <span class="hlt">frequencies</span> (40 and 70 push min(-1)), with one of two different push strategies [synchronous (SYN): both arms pushing together, and asynchronous: one arm applying force to the wheel at a time). Physiological measures included oxygen uptake ( VO(2)), heart rate (HR) and blood lactate [La](b )concentration. Differentiated ratings of perceived exertion (RPE) were also recorded (overall, local and central). <span class="hlt">Separate</span> ANOVA were used for VO(2), HR, [La](b) and RPE as the dependent variables. Where significant differences were identified, a Bonferroni post hoc test was used. The main effect for push <span class="hlt">frequency</span> by strategy was significant for VO(2) ( P<0.01). Scrutiny of the HR values showed that the SYN 40 condition was significantly less stressful than all other <span class="hlt">frequency</span>-strategy combinations ( P<0.01). RPE data supported these findings although they were found to be non-significant. When looking at [La](b,) both of the main effects were also significant showing the concentration was lower on average when the push rate was 40 as opposed to 70 (1.65 vs 2.14 mmol l(-1); P<0.01). This study provides further evidence that a low push <span class="hlt">frequency</span> provides the most economical form of wheelchair propulsion especially when combined with a SYN strategy.</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://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://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/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('https://www.ncbi.nlm.nih.gov/pubmed/28690505','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28690505"><span>Evidence for <span class="hlt">Separate</span> Contributions of High and Low Spatial <span class="hlt">Frequencies</span> during Visual Word Recognition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Winsler, Kurt; Holcomb, Phillip J; Midgley, Katherine J; Grainger, Jonathan</p> <p>2017-01-01</p> <p>Previous studies have shown that different spatial <span class="hlt">frequency</span> information processing streams interact during the recognition of visual stimuli. However, it is a matter of debate as to the contributions of high and low spatial <span class="hlt">frequency</span> (HSF and LSF) information for visual word recognition. This study examined the role of different spatial <span class="hlt">frequencies</span> in visual word recognition using event-related potential (ERP) masked priming. EEG was recorded from 32 scalp sites in 30 English-speaking adults in a go/no-go semantic categorization task. Stimuli were white characters on a neutral gray background. Targets were uppercase five letter words preceded by a forward-mask (#######) and a 50 ms lowercase prime. Primes were either the same word (repeated) or a different word (un-repeated) than the subsequent target and either contained only high, only low, or full spatial <span class="hlt">frequency</span> information. Additionally within each condition, half of the prime-target pairs were high lexical <span class="hlt">frequency</span>, and half were low. In the full spatial <span class="hlt">frequency</span> condition, typical ERP masked priming effects were found with an attenuated N250 (sub-lexical) and N400 (lexical-semantic) for repeated compared to un-repeated primes. For HSF primes there was a weaker N250 effect which interacted with lexical <span class="hlt">frequency</span>, a significant reversal of the effect around 300 ms, and an N400-like effect for only high lexical <span class="hlt">frequency</span> word pairs. LSF primes did not produce any of the classic ERP repetition priming effects, however they did elicit a distinct early effect around 200 ms in the opposite direction of typical repetition effects. HSF information accounted for many of the masked repetition priming ERP effects and therefore suggests that HSFs are more crucial for word recognition. However, LSFs did produce their own pattern of priming effects indicating that larger scale information may still play a role in word recognition.</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('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('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=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> <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('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('http://adsabs.harvard.edu/abs/2017EGUGA..1913842L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1913842L"><span>Relative importance of precipitation <span class="hlt">frequency</span> and intensity in inter-annual <span class="hlt">variation</span> of precipitation in Singapore during 1980-2013</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Xin; Babovic, Vladan</p> <p>2017-04-01</p> <p>Observed studies on inter-annual <span class="hlt">variation</span> of precipitation provide insight into the response of precipitation to anthropogenic climate change and natural climate variability. Inter-annual <span class="hlt">variation</span> of precipitation results from the concurrent <span class="hlt">variations</span> of precipitation <span class="hlt">frequency</span> and intensity, understanding of the relative importance of <span class="hlt">frequency</span> and intensity in the variability of precipitation can help fathom its changing properties. Investigation of the long-term changes of precipitation schemes has been extensively carried out in many regions across the world, however, detailed studies of the relative importance of precipitation <span class="hlt">frequency</span> and intensity in inter-annual <span class="hlt">variation</span> of precipitation are still limited, especially in the tropics. Therefore, this study presents a comprehensive framework to investigate the inter-annual <span class="hlt">variation</span> of precipitation and the dominance of precipitation <span class="hlt">frequency</span> and intensity in a tropical urban city-state, Singapore, based on long-term (1980-2013) daily precipitation series from 22 rain gauges. First, an iterative Mann-Kendall trend test method is applied to detect long-term trends in precipitation total, <span class="hlt">frequency</span> and intensity at both annual and seasonal time scales. Then, the relative importance of precipitation <span class="hlt">frequency</span> and intensity in inducing the inter-annual <span class="hlt">variation</span> of wet-day precipitation total is analyzed using a dominance analysis method based on linear regression. The results show statistically significant upward trends in wet-day precipitation total, <span class="hlt">frequency</span> and intensity at annual time scale, however, these trends are not evident during the monsoon seasons. The inter-annual <span class="hlt">variation</span> of wet-day precipitation is mainly dominated by precipitation intensity for most of the stations at annual time scale and during the Northeast monsoon season. However, during the Southwest monsoon season, the inter-annual <span class="hlt">variation</span> of wet-day precipitation is mainly dominated by precipitation <span class="hlt">frequency</span>. These results have</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('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/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('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. (c) 2010 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H13L1578B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H13L1578B"><span><span class="hlt">Variation</span> in the extent of ecohydrologic <span class="hlt">separation</span> in mixed conifer forest</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bowers, W.; Williams, D. G.</p> <p>2016-12-01</p> <p>It is now widely accepted that water used for tree transpiration can be <span class="hlt">separate</span> from water that supplies groundwater and streamflow. Broad evidence of such ecohydrologic <span class="hlt">separation</span> forms the basis for the "two water worlds hypothesis" that challenges commonly held notions of how water moves through terrestrial ecosystems. Isotopic evidence supports that trees take up water from tightly bound soil pore spaces that often is not fully mixed with loosely bound water that eventually flows to groundwater and streams. Conditions that promote ecohydrologic <span class="hlt">separation</span> and reduce complete mixing of loosely bound and tightly bound water in soil likely vary across soil types and complex topography in forested catchments. We examined the isotopic signature of water in three tree species, bulk soil, loosely bound soil water collected from soil lysimeters, and stream water at three different hillslopes in a mixed confer forest in southeastern Wyoming. Hillslopes differed in aspect and topographic position with corresponding differences in surface energy balance, snowmelt timing, and duration of soil moisture during the dry summer. We expect the magnitude of hydrologic <span class="hlt">separation</span> would differ across the three hillslopes because of the these different physical conditions. One species sampled, lodgepole pine (Pinus contorta), is "isohydric"; stomatal conductance is regulated such that leaf water potential declines to a relatively high set point value during daily transpiration. The other two species, Engelmann spruce (Picea engelmannia) and sub-alpine fir (Abies laziocarpa) are "anisohydric", in that they allow daily minimum values of leaf water potential to vary and drop to values below that sustained by lodgepole pine. We predicted that ecohydrologic <span class="hlt">separation</span> would be expressed to a greater degree on comparatively dry hillslopes and in species with anisohydric stomatal regulation. Quantifying and understanding such patterns of ecohydrological <span class="hlt">separation</span> is important for</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('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('http://adsabs.harvard.edu/abs/2016PhDT.......183H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhDT.......183H"><span>Experimental investigation on the effects of non-cyclical <span class="hlt">frequency</span> and amplitude <span class="hlt">variation</span> on dynamic stall</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heintz, Kyle C.</p> <p></p> <p>An experimental study of a cambered airfoil undergoing non-cyclical, transient pitch trajectories and the resulting effects on the dynamic stall phenomenon is presented. Surface pressure measurements and airfoil incidence angle are acquired simultaneously to resolve instantaneous aerodynamic load coefficients at Mach numbers ranging from 0.2 to 0.4. Derived from these coefficients are various formulations of the aerodynamic damping factor, referred to copiously throughout. Using a two-motor mechanism, each providing independent <span class="hlt">frequency</span> and amplitude input to the airfoil, unique pitch motions can be implemented by actively controlling the phase between inputs. This work primarily focuses on three pitch motion schemas, the first of which is a "chirp" style trajectory featuring concurrent exponential <span class="hlt">frequency</span> growth and amplitude decay. Second, these parameters are tested <span class="hlt">separately</span> to determine their individual contributions. Lastly, a novel dual harmonic pitch motion is devised which rapidly traverses dynamic stall regimes on an inter-cycle basis by modulating the static-stall penetration angle. Throughout all results presented, there is evidence that for consecutive pitch-cycles, the process of dynamic stall is affected when prior oscillations prior have undergone deeper stall-penetration angles. In other words when stall-penetration is descending, retreating from a regime of light or deep stall, statistics of load coefficients, such as damping coefficient, maximum lift, minimum quarter-chord moment, and their phase relationships, do not match the values seen when stall-penetration was growing. The outcomes herein suggest that the airfoil retains some memory of previous flow <span class="hlt">separation</span> which has the potential to change the influence of the dynamic stall vortex.</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('https://www.ncbi.nlm.nih.gov/pubmed/28783163','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28783163"><span><span class="hlt">Frequency</span> of mononuclear diploid cardiomyocytes underlies natural <span class="hlt">variation</span> in heart regeneration.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Patterson, Michaela; Barske, Lindsey; Van Handel, Ben; Rau, Christoph D; Gan, Peiheng; Sharma, Avneesh; Parikh, Shan; Denholtz, Matt; Huang, Ying; Yamaguchi, Yukiko; Shen, Hua; Allayee, Hooman; Crump, J Gage; Force, Thomas I; Lien, Ching-Ling; Makita, Takako; Lusis, Aldons J; Kumar, S Ram; Sucov, Henry M</p> <p>2017-09-01</p> <p>Adult mammalian cardiomyocyte regeneration after injury is thought to be minimal. Mononuclear diploid cardiomyocytes (MNDCMs), a relatively small subpopulation in the adult heart, may account for the observed degree of regeneration, but this has not been tested. We surveyed 120 inbred mouse strains and found that the <span class="hlt">frequency</span> of adult mononuclear cardiomyocytes was surprisingly variable (>7-fold). Cardiomyocyte proliferation and heart functional recovery after coronary artery ligation both correlated with pre-injury MNDCM content. Using genome-wide association, we identified Tnni3k as one gene that influences <span class="hlt">variation</span> in this composition and demonstrated that Tnni3k knockout resulted in elevated MNDCM content and increased cardiomyocyte proliferation after injury. Reciprocally, overexpression of Tnni3k in zebrafish promoted cardiomyocyte polyploidization and compromised heart regeneration. Our results corroborate the relevance of MNDCMs in heart regeneration. Moreover, they imply that intrinsic heart regeneration is not limited nor uniform in all individuals, but rather is a variable trait influenced by multiple genes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4406589','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4406589"><span>Extreme Recombination <span class="hlt">Frequencies</span> Shape Genome <span class="hlt">Variation</span> and Evolution in the Honeybee, Apis mellifera</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wallberg, Andreas; Glémin, Sylvain; Webster, Matthew T.</p> <p>2015-01-01</p> <p>Meiotic recombination is a fundamental cellular process, with important consequences for evolution and genome integrity. However, we know little about how recombination rates vary across the genomes of most species and the molecular and evolutionary determinants of this <span class="hlt">variation</span>. The honeybee, Apis mellifera, has extremely high rates of meiotic recombination, although the evolutionary causes and consequences of this are unclear. Here we use patterns of linkage disequilibrium in whole genome resequencing data from 30 diploid honeybees to construct a fine-scale map of rates of crossing over in the genome. We find that, in contrast to vertebrate genomes, the recombination landscape is not strongly punctate. Crossover rates strongly correlate with levels of genetic <span class="hlt">variation</span>, but not divergence, which indicates a pervasive impact of selection on the genome. Germ-line methylated genes have reduced crossover rate, which could indicate a role of methylation in suppressing recombination. Controlling for the effects of methylation, we do not infer a strong association between gene expression patterns and recombination. The site <span class="hlt">frequency</span> spectrum is strongly skewed from neutral expectations in honeybees: rare variants are dominated by AT-biased mutations, whereas GC-biased mutations are found at higher <span class="hlt">frequencies</span>, indicative of a major influence of GC-biased gene conversion (gBGC), which we infer to generate an allele fixation bias 5 – 50 times the genomic average estimated in humans. We uncover further evidence that this repair bias specifically affects transitions and favours fixation of CpG sites. Recombination, via gBGC, therefore appears to have profound consequences on genome evolution in honeybees and interferes with the process of natural selection. These findings have important implications for our understanding of the forces driving molecular evolution. PMID:25902173</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> </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://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="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2014-09-01</p> <p>cube for s = 1, 2, 3 respectively, with grid size h = k−1−δ/2. Denote the grid point as ym,m = 1, 2, . . . , N h k = k s(1+δ/2). Denote the liner ...geometric optics ansatz as discussed in Section 2.2. 2) X and Y are two disjoint thin cylinders around a line as shown in Figure 9(b). This 3D setup...boundary to X,Y is small compared to the wavelength and the <span class="hlt">separation</span> distance between X and Y , the special setup of two thin cylinders in Section 4.2 or</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('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('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('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/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/18971956','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18971956"><span>Genetic and morphological patterns show <span class="hlt">variation</span> in <span class="hlt">frequency</span> of hybrids between Ipomopsis (Polemoniaceae) zones of sympatry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Aldridge, G; Campbell, D R</p> <p>2009-03-01</p> <p><span class="hlt">Variation</span> in rates of hybridization among zones of sympatry between a pair of species provides a useful window into the effect of local conditions on the evolution of reproductive isolation. We employed floral morphological traits and neutral genetic markers to quantify the <span class="hlt">frequency</span> of individuals intermediate to the two parental species in two zones of sympatry between Ipomopsis aggregata and I. tenuituba, using clustering methods that make no a priori assumptions about population structure. The sites differed not only in the <span class="hlt">frequency</span> of intermediate individuals, but also in climate, pollinator abundance and behavior and spatial structure of plant populations. Both floral traits, which are likely to be under natural selection and molecular markers, which are quasi-neutral, indicated more population structure at one site than the other, the pattern being more pronounced for floral morphology. One likely explanation for this difference between sites is that local ecological conditions, particularly pollinator choice of flowers, have promoted different rates of hybridization between these species. Hence, the evolution of reproductive isolation might depend in part on local conditions, and thus differ among populations of the same pair of species.</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('https://www.ncbi.nlm.nih.gov/pubmed/27683967','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27683967"><span>Adult <span class="hlt">separation</span> anxiety disorder in complicated grief: an exploratory study on <span class="hlt">frequency</span> and correlates.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gesi, Camilla; Carmassi, Claudia; Shear, Katherine M; Schwartz, Theresa; Ghesquiere, Angela; Khaler, Julie; Dell'Osso, Liliana</p> <p>2017-01-01</p> <p>Complicated grief (CG) has been the subject of increasing attention in the past decades but its relationship with <span class="hlt">separation</span> anxiety disorder (SEPAD) is still controversial. The aim of the current study was to explore the prevalence and clinical significance of adult SEPAD in a sample of help-seeking individuals with CG. 151 adults with CG, enrolled in a randomized controlled trial comparing the effectiveness of (CG) treatment to that of interpersonal therapy, were assessed by means of the Inventory of Complicated Grief (ICG), the Structured Clinical Interview for DSM-IV, the Hamilton Rating Scale for Depression (HAM-D), the Work and Social Adjustment Scale (WSAS), the Adult <span class="hlt">Separation</span> Anxiety Questionnaire (ASA-27), the Grief Related Avoidance Questionnaire (GRAQ), the Peritraumatic Dissociative Experiences Questionnaire (PDEQ), and the Impact of Events Scale (IES). 104 (68.9%) individuals with CG were considered to have SEPAD (ASA-27 score ≥22). Individuals with SEPAD were more likely to have reported a CG related to the loss of another close relative or friend (than a parent, spouse/partner or a child) (p=.02), as well as greater scores on the ICG (p=<.001), PDEQ (p=.004), GRAQ (p<.001), intrusion (p<.001) and avoidance (p=<.001) IES subscales, HAM-D (p<.001) and WSAS (p=.006). ASA-27 total scores correlated with ICG (p<.0001), PDEQ (p<.001) GRAQ (p<.0001) scores and both the IES intrusion (p<.0001) and IES avoidance (p<.0001) subscale scores. People with SEPAD had higher rates of lifetime post-traumatic stress disorder (PTSD) (p=.04) and panic disorder (PD) (p=.01). SEPAD is highly prevalent among patients with CG and is associated with greater symptom severity and impairment and greater comorbidity with PTSD and PD. Further studies will help to confirm and generalize our results and to determine whether adult SEPAD responds to CG treatment and/or moderates CG treatment response. Copyright © 2016 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4871142','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4871142"><span>Evaluation of range-<span class="hlt">separated</span> hybrid density functionals for the prediction of vibrational <span class="hlt">frequencies</span>, infrared intensities, and Raman activities†</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jiménez-Hoyos, Carlos A.; Janesko, Benjamin G.</p> <p>2016-01-01</p> <p>We present an assessment of different density functionals, with emphasis on range-<span class="hlt">separated</span> hybrids, for the prediction of fundamental and harmonic vibrational <span class="hlt">frequencies</span>, infrared intensities, and Raman activities. Additionally, we discuss the basis set convergence of vibrational properties of H2O with long-range corrected hybrids. Our results show that B3LYP is the best functional for predicting vibrational <span class="hlt">frequencies</span> (both fundamental and harmonic); the screened-PBE hybrid (HSE) density functional works best for infrared intensities, and the long-range corrected PBE (LC-ωPBE), M06-HF, and M06-L density functionals are almost as good as MP2 for predicting Raman activities. We show the predicted Raman spectrum of adenine as an example of a medium-size molecule where a DFT/Sadlej pVTZ calculation is affordable and compare our results against the experimental spectrum. PMID:18989473</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://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> <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/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.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('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('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/2016AGUFM.T31G..04W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.T31G..04W"><span>Interactions between phase <span class="hlt">separation</span>, mineral precipitation, and permeability <span class="hlt">variations</span> in saline magmatic-hydrothermal system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weis, P.</p> <p>2016-12-01</p> <p>Fluid flow through permeable rocks in saline magmatic-hydrothermal systems is influenced by non-linear fluid and rock properties as well as physical and chemical fluid-rock interactions. The same processes are of critical importance to a variety of different disciplines of Earth sciences such as volcanology, geothermal energy, hydrogeology and economic geology, and progress in understanding the relative importance of the interactions between different processes requires multi-method approaches investigating both active and fossil hydrothermal systems. Observations and model results suggest that many of these systems are highly dynamic and have a potential for self-organization, optimizing heat and mass transport by fluids in the upper crust. For example, numerical simulations in combination with oxygen isotopes of vein quartz suggest that ore precipitation in porphyry copper deposits occurs at the hydrological interface between a dynamic plume of ascending magmatic fluids and meteoric water convection, which is controlled by the transition from ductile to brittle rock behavior. With increasing ductile behavior, we infer that locally host rock permeability is reduced and the regional stress state is relaxed, resulting in fluid pressure build-up to near-lithostatic values with continued fluid expulsion, which eventually leads to episodic brittle failure of otherwise nominally ductile rocks. Sharp pressure drops and phase <span class="hlt">separation</span> at this hydrological front can lead to saturation in solid halite, which is indicated to be a ubiquitous feature in hydrothermal systems associated with upper crustal plutons both by fluid inclusion studies and numerical simulations. Precipitation of solid halite can also lead to permeability reduction and evoke pulsating fluid migration. The presentation will show analytical and numerical results describing the role of non-linear fluid properties, phase <span class="hlt">separation</span>, salt precipitation, fluid mixing, hydraulic fracturing and the brittle</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> </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/27594968','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27594968"><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="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nolden, Alissa A; Hayes, John E</p> <p>2015-09-01</p> <p>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. 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. 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. 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011IJTIA.131..403M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011IJTIA.131..403M"><span>Adaptive Feedforward Compensation by Specified Step Settling Considering Resonance <span class="hlt">Frequency</span> <span class="hlt">Variation</span> and Constraint on Control Input Amplitude</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maeda, Yoshihiro; Wada, Masatake; Iwasaki, Makoto; Hirai, Hiromu</p> <p></p> <p>This paper presents an adaptive feedfowad (FF) compensation method based on a deadbeat control framework for fast and precise positioning in mechatronic systems. The conventional FF compensation approach can design a FF compensator by considering both the <span class="hlt">frequency</span> shaping and amplitude of FF control input, to suppress the response <span class="hlt">variations</span> due to the perturbations in plant resonance <span class="hlt">frequency</span>. However, since the conventional approach is not adaptive against <span class="hlt">frequency</span> <span class="hlt">variations</span>, an overshoot and/or undershoot response at the settling region would deteriorate the positioning performance. In this research, therefore, the proposed FF compensation approach with an adaptive identification system for the resonance <span class="hlt">frequency</span> is adopted to achieve the desired positioning performance. The effectiveness of the proposed FF compensation approach has been verified by experiments using a prototype of an industrial positioning device.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JHyd..553..486Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JHyd..553..486Q"><span>Assessing the ecohydrological <span class="hlt">separation</span> hypothesis and seasonal <span class="hlt">variations</span> in water use by Ginkgo biloba L. in a subtropical riparian area</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qian, Jin; Zheng, Hao; Wang, Peifang; Liao, Xiaolin; Wang, Chao; Hou, Jun; Ao, Yanhui; Shen, Mengmeng; Liu, Jingjing; Li, Kun</p> <p>2017-10-01</p> <p>In this study we used a dual stable isotope approach (δ18O and δ2H) to assess the ecohydrological <span class="hlt">separation</span> hypothesis and to identify the seasonal <span class="hlt">variation</span> in water sources of Ginkgo biloba L. in the riparian zone in the Taihu Lake basin, China. Three study sites located at 5, 10, and 30 m from a river bank were established. From August 2014 to July 2015, samples of rainwater, river water, groundwater, bulk soil water at five soil depths (i.e. 0-30, 30-60, 60-90, 90-120, 120-150 cm), and xylem water of G. biloba, were collected and their δ18O and δ2H values were measured. Generally, the δ18O and δ2H values for xylem water, groundwater, and soil water clustered together and <span class="hlt">separated</span> from those of river water, suggesting the possible occurrence of ecohydrological <span class="hlt">separation</span>. However, the line-conditioned excess (lc-excess) values of most xylem water were positive, indicating a mixture of different water sources. Significant correlations were observed between the contributions of precipitation, soil water, and groundwater to water uptake by G. biloba, further supporting ecohydrological connectivity rather than ecohydrological <span class="hlt">separation</span>. G. biloba switched its major water sources from soil water at 0-60 cm depth and precipitation in the wet summer, to soil water from >90 cm depth and groundwater in the dry winter. The river water was a minor water source for G. biloba, but its contribution was comparatively greater at the site closest to the river bank. Our findings contribute to understanding of plant-soil-water relationships and the water balance, and may provide important information for investigations of nutrient sources and sinks in riparian zones. The present study suggests the need to rethink the application of ecohydrological connectivity and <span class="hlt">separation</span> in different biomes, especially where river water and groundwater recharge each other over time.</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. PMID:28401118</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/2016AGUFM.G11B1076Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.G11B1076Z"><span><span class="hlt">Separating</span> Mass and Height Contributions in Gravity <span class="hlt">Variations</span> at Medicina, Italy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zerbini, S.; Bruni, S.; Errico, M.; Santi, E.; Wziontek, H.</p> <p>2016-12-01</p> <p>During 1996, at the Medicina station, a GPS and a superconducting gravimeter (SG) were installed in the framework of an experiment focused on the comparison between height and gravity <span class="hlt">variations</span>. Absolute gravity observations are also performed twice a year and environmental parameters, among others water table levels, are recorded continuously. The station is also equipped with a second GPS system, the two antennas are very close to each other, and both are located in close proximity to the VLBI dish. Two decades of continuous height and gravity observations are now available which allow investigating both long and short period signals and the relevant correlations between the two measured quantities. Long period signatures are observed, a principal component is due to subsidence which is well known to occur in the area; however, also non-linear long-period behaviors are observed. Seasonal effects are also clearly recognizable in the time series and are mainly associated with the water table seasonal behavior. The station is characterized by clayey soil which is subject to consolidation effects when the water table lowers during the summer period. This effect is particularly recognizable in the SG data since the instrument is installed on a shallow foundation pillar which may suffer for height decreases in the order of 2,5-3 cm for water table lowering of 2 m.</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('https://www.osti.gov/scitech/biblio/21454820','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21454820"><span>Approximate formulas for the resonance <span class="hlt">frequency</span> shift in cavities with big <span class="hlt">variations</span> of parameters inside small regions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dodonov, V. V.</p> <p>2010-10-15</p> <p>The Mueller-Bethe-Schwinger-Casimir formulas for the <span class="hlt">frequency</span> shift in electromagnetic resonators are generalized to the case of big <span class="hlt">variations</span> of electric permittivity inside small regions. These formulas are important, in particular, for the studies of the dynamical Casimir effect.</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.ncbi.nlm.nih.gov/pubmed/25380961','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25380961"><span>Ulysses: accurate detection of low-<span class="hlt">frequency</span> structural <span class="hlt">variations</span> in large insert-size sequencing libraries.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gillet-Markowska, Alexandre; Richard, Hugues; Fischer, Gilles; Lafontaine, Ingrid</p> <p>2015-03-15</p> <p>The detection of structural <span class="hlt">variations</span> (SVs) in short-range Paired-End (PE) libraries remains challenging because SV breakpoints can involve large dispersed repeated sequences, or carry inherent complexity, hardly resolvable with classical PE sequencing data. In contrast, large insert-size sequencing libraries (Mate-Pair libraries) provide higher physical coverage of the genome and give access to repeat-containing regions. They can thus theoretically overcome previous limitations as they are becoming routinely accessible. Nevertheless, broad insert size distributions and high rates of chimerical sequences are usually associated to this type of libraries, which makes the accurate annotation of SV challenging. Here, we present Ulysses, a tool that achieves drastically higher detection accuracy than existing tools, both on simulated and real mate-pair sequencing datasets from the 1000 Human Genome project. Ulysses achieves high specificity over the complete spectrum of variants by assessing, in a principled manner, the statistical significance of each possible variant (duplications, deletions, translocations, insertions and inversions) against an explicit model for the generation of experimental noise. This statistical model proves particularly useful for the detection of low <span class="hlt">frequency</span> variants. SV detection performed on a large insert Mate-Pair library from a breast cancer sample revealed a high level of somatic duplications in the tumor and, to a lesser extent, in the blood sample as well. Altogether, these results show that Ulysses is a valuable tool for the characterization of somatic mosaicism in human tissues and in cancer genomes. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.</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> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23711074','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23711074"><span>Effects of magnitude and <span class="hlt">frequency</span> of <span class="hlt">variations</span> in external power output on simulated cycling time-trial performance.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wells, Marc; Atkinson, Greg; Marwood, Simon</p> <p>2013-01-01</p> <p>Mechanical models of cycling time-trial performance have indicated adverse effects of <span class="hlt">variations</span> in external power output on overall performance times. Nevertheless, the precise influences of the magnitude and number of these <span class="hlt">variations</span> over different distances of time trial are unclear. A hypothetical cyclist (body mass 70 kg, bicycle mass 10 kg) was studied using a mathematical model of cycling, which included the effects of acceleration. Performance times were modelled over distances of 4-40 km, mean power outputs of 200-600 W, power <span class="hlt">variation</span> amplitudes of 5-15% and <span class="hlt">variation</span> <span class="hlt">frequencies</span> of 2-32 per time-trial. Effects of a "fast-start" strategy were compared with those of a constant-power strategy. Varying power improved 4-km performance at all power outputs, with the greatest improvement being 0.90 s for ± 15% power <span class="hlt">variation</span>. For distances of 16.1, 20 and 40 km, varying power by ± 15% increased times by 3.29, 4.46 and 10.43 s respectively, suggesting that in long-duration cycling in constant environmental conditions, cyclists should strive to reduce power <span class="hlt">variation</span> to maximise performance. The novel finding of the present study is that these effects are augmented with increasing event distance, amplitude and period of <span class="hlt">variation</span>. These two latter factors reflect a poor adherence to a constant speed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7597E..2AM','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7597E..2AM"><span>VCSEL's <span class="hlt">frequency</span> stabilization of an external cavity diode laser: countermeasures against atmospheric temperature <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>Motojima, Mutsuki; Doi, Kohei; Sato, Takashi; Ohkawa, Masashi; Suzuki, Takamasa</p> <p>2010-02-01</p> <p>We introduced the vertical cavity surface emitting laser (VCSEL) as the laser diode in tour external cavity system. Because VCSELs are now commercially available, and the External cavity diode laser (ECDL) systems using them are expected to improve their <span class="hlt">frequency</span> stability, we have replaced a Fabry-Perot type laser diode with a VCSEL, and examined its oscillation-<span class="hlt">frequency</span> stability. Therefore we were able to expect that the VCSELs with our double optical feedback system have good oscillation <span class="hlt">frequency</span> stability. The obtained VCSEL's oscillation-<span class="hlt">frequency</span> stability, i.e., the square root of Allan variance σ was 4×10-10, at an averaging time of τ=1 sec.</p> </li> <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('https://www.ncbi.nlm.nih.gov/pubmed/26935894','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26935894"><span>Low-<span class="hlt">frequency</span> and common genetic <span class="hlt">variation</span> in ischemic stroke: The METASTROKE collaboration.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>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; Dichgans, Martin</p> <p>2016-03-29</p> <p>To investigate the influence of common and low-<span class="hlt">frequency</span> genetic variants on the risk of ischemic stroke (all IS) and etiologic stroke subtypes. 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 <span class="hlt">frequencies</span> for all IS and stroke subtypes. 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 <span class="hlt">frequency</span> bins, we showed significant enrichment in low-<span class="hlt">frequency</span> variants (allele <span class="hlt">frequency</span> <5%) for both LVD and small vessel disease, and an enrichment of higher <span class="hlt">frequency</span> variants (allele <span class="hlt">frequency</span> 10% and 30%) for CE (all p < 1E-5). Our findings suggest that the missing heritability in IS subtypes can in part be attributed to low-<span class="hlt">frequency</span> and rare variants. Larger sample sizes are needed to identify the variants associated with all IS and stroke subtypes. © 2016 American Academy of Neurology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ArtSa..52...19F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ArtSa..52...19F"><span><span class="hlt">Variation</span> of Static-PPP Positioning Accuracy Using GPS-Single <span class="hlt">Frequency</span> Observations (Aswan, Egypt)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farah, Ashraf</p> <p>2017-06-01</p> <p>Precise Point Positioning (PPP) is a technique used for position computation with a high accuracy using only one GNSS receiver. It depends on highly accurate satellite position and clock data rather than broadcast ephemeries. PPP precision varies based on positioning technique (static or kinematic), observations type (single or dual <span class="hlt">frequency</span>) and the duration of collected observations. PPP-(dual <span class="hlt">frequency</span> receivers) offers comparable accuracy to differential GPS. PPP-single <span class="hlt">frequency</span> receivers has many applications such as infrastructure, hydrography and precision agriculture. PPP using low cost GPS single-<span class="hlt">frequency</span> receivers is an area of great interest for millions of users in developing countries such as Egypt. This research presents a study for the variability of single <span class="hlt">frequency</span> static GPS-PPP precision based on different observation durations.</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://adsabs.harvard.edu/abs/2014cosp...40E1512K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E1512K"><span>A time-<span class="hlt">frequency</span> approach to distinguish diurnal and lunar <span class="hlt">variations</span> in measurements of ground magnetic and TEC data.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klausner, Virginia; Fontes Gomes, Anna Karina; Candido, Claudia; Frick, Peter; Mendes, Odim; Reinaldo Rodriguez Papa, Andres; Oliveira Domingues, Margarete; Negreti, Patricia M. S.</p> <p></p> <p>Here, we explore the diurnal and lunar <span class="hlt">variations</span> in measurements of ground magnetic and TEC data by using gapped wavelet technique. We analyze the last solar minimum period of solar cycle 23, which presented unusually low and prolonged solar activity, providing a good opportunity to investigate the impact of wave activity on the system thermosphere-ionosphere. It is well-known that wavelets are localized in both the time and <span class="hlt">frequency</span> domains because wavelets have limited time duration and <span class="hlt">frequency</span> bandwidth. For instance the Morlet wavelet has a long support in physical space and a short support in Fourier space as expected by the Heisenberg's uncertainty principle. For this reason, here we applied the Morlet wavelet with different temporal parameters to improve the <span class="hlt">frequency</span> resolution (bandwidth), and also, to distinguish the physical phenomena of our interest. We try to determine the dominant timescales related to the signature of 12 h (semidiurnal <span class="hlt">variations</span>) and 12.42 h (semilunar <span class="hlt">variations</span>), therefore the appropriate choices of temporal parameter allow us to determine which kinds of information can be extracted.</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('http://adsabs.harvard.edu/abs/2006NIMPA.569..581K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006NIMPA.569..581K"><span>Single-<span class="hlt">frequency</span> and multiband microwave radiometry for feasible brain conductivity <span class="hlt">variation</span> imaging during reactions to external stimuli</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karanasiou, I. S.; Uzunoglu, N. K.</p> <p>2006-12-01</p> <p>Recent research results imply that microwave radiometry may exhibit the capability of detecting local <span class="hlt">variations</span> of the conductivity attributes of the media under measurement. The contactless measurements in question are a function of the geometrical spatial properties of a newly developed microwave radiometry imaging system (MiRaIS), comprising an ellipsoidal conductive wall cavity. The proposed methodology is based on single-<span class="hlt">frequency</span> and multiband microwave radiometry in conjunction with the implementation of an ellipsoidal reflector to achieve focusing on the areas of interest. The theoretical fundamentals as well as an overview of the system modules and past experimental results are herein presented, forming the background and context on which current and future research is based. Experimentation using small water phantoms in order to verify the system's focusing properties and saline solution phantoms in order to investigate the system's capability of sensing conductivity changes at various microwave <span class="hlt">frequencies</span> with a sensitive multiband receiver has been conducted. The results show that local resistance <span class="hlt">variations</span> in small phantoms can be detected at microwave <span class="hlt">frequencies</span> by the MiRaIS. Combining these experimental data with previous human experimental results, the feasibility of brain conductivity <span class="hlt">variation</span> imaging during reactions to external stimuli by the proposed system is examined and discussed in the present paper.</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="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</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://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/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=Huntington&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','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=189923&keyword=Huntington&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"><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://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/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('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('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('http://adsabs.harvard.edu/abs/2008SPIE.6889E..18M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SPIE.6889E..18M"><span><span class="hlt">Frequency</span> stabilization of an external cavity diode laser: countermeasures against atmospheric temperature <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>Minabe, Yuta; Doi, Kohei; Sato, Takashi; Maruyama, Takeo; Ohkawa, Masashi; Tsubokawa, Tsuneya</p> <p>2008-02-01</p> <p>External cavity diode lasers (ECDL) are presently experiencing a surge in popularity, as laser light-sources for advanced optical measurement systems. While these devices normally require external optical-output controls, we simplified the setup, a bit, by adding a second external cavity. This technique boasts the added advantage of having a narrower oscillation-linewidth than would be achievable, using a single optical feedback. Because drive-current and atmospheric temperature directly impact the ECDL systems' oscillation <span class="hlt">frequency</span>, during <span class="hlt">frequency</span> stability checks, it was necessary, in this instance, to construct a slightly smaller ECDL system, which we mounted on a Super-Invar board, to minimize the influence of thermal expansion. Taking these and other aggressive and timely measures to prevent atmospheric temperature-related changes allowed us to achieve an improvement in oscillation-<span class="hlt">frequency</span> stability, i.e., to obtain the square root of Allan variance σ =2×10 -10, at averaging time τ =10 -1. We introduced a vertical-cavity surface-emitting laser (VCSEL) to the setup, for the simple reason that its <span class="hlt">frequency</span> is far less susceptible to changes in temperature, than other lasers of its type. And, because VCSELs are widely available, and the ECDL systems that use them improve <span class="hlt">frequency</span> stability, we replaced the Fabry-Perot semiconductor laser with a VCSEL.</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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5606140','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5606140"><span>High-<span class="hlt">Frequency</span> EEG <span class="hlt">Variations</span> in Children with Autism Spectrum Disorder during Human Faces Visualization</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Reategui, Camille; Costa, Bruna Karen de Sousa; da Fonseca, Caio Queiroz; da Silva, Luana; Morya, Edgard</p> <p>2017-01-01</p> <p>Autism spectrum disorder (ASD) is a neuropsychiatric disorder characterized by the impairment in the social reciprocity, interaction/language, and behavior, with stereotypes and signs of sensory function deficits. Electroencephalography (EEG) is a well-established and noninvasive tool for neurophysiological characterization and monitoring of the brain electrical activity, able to identify abnormalities related to <span class="hlt">frequency</span> range, connectivity, and lateralization of brain functions. This research aims to evidence quantitative differences in the <span class="hlt">frequency</span> spectrum pattern between EEG signals of children with and without ASD during visualization of human faces in three different expressions: neutral, happy, and angry. Quantitative clinical evaluations, neuropsychological evaluation, and EEG of children with and without ASD were analyzed paired by age and gender. The results showed stronger activation in higher <span class="hlt">frequencies</span> (above 30 Hz) in frontal, central, parietal, and occipital regions in the ASD group. This pattern of activation may correlate with developmental characteristics in the children with ASD. PMID:29018811</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('http://adsabs.harvard.edu/abs/2015AIPC.1650..336G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AIPC.1650..336G"><span>Quantitatively analyzing dielectrical properties of resins and mapping permittivity <span class="hlt">variations</span> in CFRP with high-<span class="hlt">frequency</span> eddy current device technology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gäbler, Simone; Heuer, Henning; Heinrich, Gert; Kupke, Richard</p> <p>2015-03-01</p> <p>Eddy current testing is well-established for non-destructive characterization of electrical conductive materials. The development of high-<span class="hlt">frequency</span> eddy current technology (with <span class="hlt">frequency</span> ranges up to 100 MHz) made it even possible to extend the classical fields of application towards less conductive materials like CFRP. Maxwell's equations and recent research show that the use of high-<span class="hlt">frequency</span> eddy current technology is also suitable for non-conductive materials. In that case the change of complex impedance of the probing coil contains information on sample permittivity. This paper shows that even a quantitative measurement of complex permittivity with high-<span class="hlt">frequency</span> eddy current device technology is possible using an appropriate calibration. Measurement accuracy is comparable to commercial capacitive dielectric analyzers. If the sample material is electrically conductive, both, permittivity and conductivity influence the complex impedance measured with high-<span class="hlt">frequency</span> eddy current devices. Depending on the measurement setup and the sheet resistance of the sample a parallel characterization of both parameters is possible on isotropic multi-layer materials. On CFRP the permittivity measurement is much more complex due to the capacitive effects between the carbon rovings. However, first results show that at least the local permittivity <span class="hlt">variations</span> (like those caused by thermal damages) are detectable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012A%26A...545A..73J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012A%26A...545A..73J"><span><span class="hlt">Variation</span> of solar oscillation <span class="hlt">frequencies</span> in solar cycle 23 and their relation to sunspot area and number</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jain, R.; Tripathy, S. C.; Watson, F. T.; Fletcher, L.; Jain, K.; Hill, F.</p> <p>2012-09-01</p> <p>Aims: Studying the long term evolution of the solar acoustic oscillations is necessary for understanding how the large-scale solar dynamo operates. In particular, an understanding of the solar cycle <span class="hlt">variation</span> in the <span class="hlt">frequencies</span> of solar oscillations can provide a powerful diagnostic tool for constraining various dynamo models. In this work, we report the temporal evolution of solar oscillations for the solar cycle 23, and correlate with solar magnetic activity indices. Methods: We use solar oscillation <span class="hlt">frequencies</span> obtained from the Michelson Doppler Imager on board the Solar and Heliospheric Observatory, correlate them with the sunspot number provided by the international sunspot number, RI, and compare them with the sunspot number calculated with the Sunspot Tracking And Recognition Algorithm (STARA). Results: We find that the mean <span class="hlt">frequency</span> shifts correlate very well with the sunspot numbers obtained from two different datasets. We also find a hysteresis-type behaviour for the STARA sunspot area and mean magnetic field strength for the different phases of the solar cycle. The increase in solar oscillation <span class="hlt">frequencies</span> precedes slightly the increase in total sunspot area and the mean magnetic field strength for the solar cycle 23. We briefly discuss the cyclic behaviour in the context of p-mode <span class="hlt">frequencies</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_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('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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4916475','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4916475"><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="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sarma, Kanak C.; Mahanta, Anil</p> <p>2016-01-01</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. PMID:27382482</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://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('https://www.ncbi.nlm.nih.gov/pubmed/28005848','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28005848"><span>Broadband microwave photonic phase shifter based on a feedback-coupled microring resonator with small radio <span class="hlt">frequency</span> power <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>Tang, Jian; Li, Ming; Sun, Shuqian; Li, Zhiyong; Li, Wei; Zhu, Ninghua</p> <p>2016-10-15</p> <p>An on-chip microwave photonic phase shifter based on an electrically tunable feedback-coupled microring resonator (FCMR) is proposed and experimentally demonstrated. By properly adjusting the voltage applied on the FCMR, the transmission spectrum with different optical extinction ratios is realized while the phase shift range remains almost unchanged. This proposal solves the conflict between the large range of phase shift and small radio <span class="hlt">frequency</span> (RF) power <span class="hlt">variation</span> in the ring-resonator-based microwave photonics phase shifter. Finally, a microwave photonic phase shifter with phase tuning of over 172 deg from 20 to 30 GHz is obtained, and the RF power <span class="hlt">variation</span> can be compressed less than 5 dB under a certain status tuned by the bias voltage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3923184','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3923184"><span>Monitoring of ULF (ultra-low-<span class="hlt">frequency</span>) Geomagnetic <span class="hlt">Variations</span> Associated with Earthquakes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hayakawa, Masashi; Hattori, Katsumi; Ohta, Kenji</p> <p>2007-01-01</p> <p>ULF (ultra-low-<span class="hlt">frequency</span>) electromagnetic emission is recently recognized as one of the most promising candidates for short-term earthquake prediction. This paper reviews previous convincing evidence on the presence of ULF emissions before a few large earthquakes. Then, we present our network of ULF monitoring in the Tokyo area by describing our ULF magnetic sensors and we finally present a few, latest results on seismogenic electromagnetic emissions for recent large earthquakes with the use of sophisticated signal processings.</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('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('http://adsabs.harvard.edu/abs/2016MS%26E..127a2019S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MS%26E..127a2019S"><span>Improving Processes of Mechanized Pulsed Arc Welding of Low-<span class="hlt">Frequency</span> Range <span class="hlt">Variation</span> of Mode Parameters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saraev, Yu N.; Solodskiy, S. A.; Ulyanova, O. V.</p> <p>2016-04-01</p> <p>A new technology of low-<span class="hlt">frequency</span> modulation of the arc current in MAG and MIG welding is presented. The technology provides control of thermal and crystallization processes, stabilizes the time of formation and crystallization of the weld pool. Conducting theoretical studies allowed formulating the basic criteria for obtaining strong permanent joints for high-duty structures, providing conditions for more equilibrium structure of the deposited metal and the smaller width of the HAZ. The stabilization of time of the formation and crystallization of the weld pool improves the formation of the weld and increases productivity in welding thin sheet metal.</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('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('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('https://www.ncbi.nlm.nih.gov/pubmed/21297168','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21297168"><span>Vowel identification by listeners with hearing impairment in response to <span class="hlt">variation</span> in formant <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>Molis, Michelle R; Leek, Marjorie R</p> <p>2011-08-01</p> <p>This study examined the influence of presentation level and mild-to-moderate hearing loss on the identification of a set of vowel tokens systematically varying in the <span class="hlt">frequency</span> locations of their second and third formants. Five listeners with normal hearing (NH listeners) and five listeners with hearing impairment (HI listeners) identified synthesized vowels that represented both highly identifiable and ambiguous examples of /i/, /[Please see symbol]/, and /[Please see symbol]/. Response patterns of NH listeners showed significant changes, with an increase in presentation level from 75 dB SPL to 95 dB SPL, including increased category overlap. HI listeners, listening only at the higher level, showed greater category overlap than normal and overall identification patterns that differed significantly from those of NH listeners. Excitation patterns based on estimates of auditory filters suggested smoothing of the internal representations, resulting in impaired formant resolution. Both increased presentation level for NH listeners and the presence of hearing loss produced a significant change in vowel identification for this stimulus set. Major differences were observed between NH listeners and HI listeners in vowel category overlap and in the sharpness of boundaries between vowel tokens. It is likely that these findings reflect imprecise internal spectral representations due to reduced <span class="hlt">frequency</span> selectivity.</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('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/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('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/2016AGUFM.A13K..08W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A13K..08W"><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, Z.</p> <p>2016-12-01</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> </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('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/2017EGUGA..1913146E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1913146E"><span>Catalogue of x-ray solar flare induced <span class="hlt">variations</span> in sub-ionospheric very low <span class="hlt">frequency</span> (VLF) waveguides</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eichelberger, Hans; Schwingenschuh, Konrad; Boudjada, Mohammed Y.; Besser, Bruno P.; Wolbang, Daniel; Rozhnoi, Alexander; Solovieva, Maria; Biagi, Pier F.; Stachel, Manfred; Prattes, Gustav; Aydogar, Özer; Muck, Cosima; Grill, Claudia; Jernej, Irmgard; Stachel, Thomas; Moro, Florian</p> <p>2017-04-01</p> <p>In this study we present a catalogue of solar flare induced very low <span class="hlt">frequency</span> (VLF) <span class="hlt">variations</span> along sub-ionospheric paths between several transmitters and the Graz seismo-electromagnetic UltraMSK receiving station. These measurements of non-seismic disturbances are important in order to carefully characterise the Earth-ionosphere VLF waveguide and disentangle possible earthquake related phenomena from natural and man-made ambient VLF amplitude and phase modifications. The period of investigation is from Jan. 2010 to April 2016, i.e. largely covers the sunspot cycle 24. In total we've 373 VLF amplitude and phase fluctuations related with C/M/X-class solar flare events (the data are from NOAA GOES x-ray flux measurements). We obtain the statistics (dependence on VLF signal vs. x-ray flux <span class="hlt">variations</span>) for high signal-to-noise ratio VLF links under consideration of the zenith angle. We conclude, that with the mid-latitude Graz VLF knot, a part of the European receiver network, a reliable service for solar flare induced <span class="hlt">variations</span> of the VLF waveguide can be established. In addition to complementary region-wide network multi-parameter observations this could be a crucial step towards a full characterisation of the behaviour of sub-ionospheric VLF paths including modifications related to seismic activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6297496','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6297496"><span>High-<span class="hlt">frequency</span> <span class="hlt">variation</span> and population drift in a newly transformed clone of BALB/3T3 cells</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rubin, H.; Arnstein, P.; Chu, B.M.</p> <p>1984-11-01</p> <p>During repeated passage of BALB/3T3 cells and testing for anchorage-independent growth, a single transformed clone was isolated from agar, and five subclones were derived from it. These subclones differed from one another in morphology on a solid substratum, efficiency and size of colony formation in agar, and rate of tumor formation in nude mice. With weekly passage over a period of 6 months, the differences in morphology and growth in agar gradually decreased. The subclone which produced the fastest-growing tumors after 18 weeks, and a change in the opposite direction was made by another subclone. There was no difference among the subclones in growth rate on plastic. The distribution of chromosome numbers was heterogeneous but overlapping in all the primary subclones at 16 and 24 weeks, with no statistically significant difference in the mean number of chromosomes per subclone. An extremely high degree of <span class="hlt">variation</span> must have occurred to produce the multiple differences between the subclones, and the same type of <span class="hlt">variation</span> could have been responsible for the subsequent changes with repeated passage. The high <span class="hlt">frequency</span> and graded nature of the changes and the concurrent involvement of several traits suggest an epigenetic basis for the <span class="hlt">variation</span>. 26 references, 8 figures, 1 table.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3345233','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3345233"><span>Bone Dielectric Property <span class="hlt">Variation</span> as a Function of Mineralization at Microwave <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>Meaney, Paul M.; Zhou, Tian; Goodwin, Douglas; Golnabi, Amir; Attardo, Elia A.; Paulsen, Keith D.</p> <p>2012-01-01</p> <p>A critical need exists for new imaging tools to more accurately characterize bone quality beyond the conventional modalities of dual energy X-ray absorptiometry (DXA), ultrasound speed of sound, and broadband attenuation measurements. In this paper we investigate the microwave dielectric properties of ex vivo trabecular bone with respect to bulk density measures. We exploit a <span class="hlt">variation</span> in our tomographic imaging system in conjunction with a new soft prior regularization scheme that allows us to accurately recover the dielectric properties of small, regularly shaped and previously spatially defined volumes. We studied six excised porcine bone samples from which we extracted cylindrically shaped trabecular specimens from the femoral heads and carefully demarrowed each preparation. The samples were subsequently treated in an acid bath to incrementally remove volumes of hydroxyapatite, and we tested them with both the microwave measurement system and a micro-CT scanner. The measurements were performed at five density levels for each sample. The results show a strong correlation between both the permittivity and conductivity and bone volume fraction and suggest that microwave imaging may be a good candidate for evaluating overall bone health. PMID:22577365</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/1995sss..conf..351S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995sss..conf..351S"><span>Low-<span class="hlt">Frequency</span> Underwater Sound Speed <span class="hlt">Variations</span> Due to Oceanic Bubbles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Su, Ming-Yang; Cartmill, John</p> <p></p> <p>The Naval Research Laboratory (NRL) has developed a measurement system called the Acoustical Resonator, which can determine in-situ size spectra of bubbles with radii ranging from about 30 to 1200 microns. This acoustical bubble system had been calibrated against two other optical bubble sensors in laboratory-controlled situations and subsequently deployed in blue-water field experiments in the past three years. Using the well-known Wood's formula for bubbly flows, the bubble spectra measured by the above system can be used for deriving the corresponding low-<span class="hlt">frequency</span> sound speed. It was found that the sound speed deficits from such combined measured-and-computed methods have reached more than 100 m/sec in the upper 1 to 2 m depth with the prevailing wind from 10 to 15 m/sec. In this paper, we shall present some of the results from a deep-water field experiment conducted in the Gulf of Alaska during Critical Sea Test (CST) 7.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19766174','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19766174"><span>Ethnic <span class="hlt">variation</span> in genotype <span class="hlt">frequencies</span> of delta-aminolevulinic acid dehydratase (ALAD).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fujihara, Junko; Agusa, Tetsuro; Yasuda, Toshihiro; Soejima, Mikiko; Kato, Hideaki; Panduro, Arturo; Koda, Yoshiro; Kimura-Kataoka, Kaori; Takeshita, Haruo</p> <p>2009-12-15</p> <p>Delta-aminolevulinic acid dehydratase (ALAD) is a cytosolic enzyme in the heme biosynthetic pathway. The ALAD is controlled by two codominant alleles (ALAD1 and ALAD2), which result in a Asn-Lys substitution at amino acid position 59 of the mature enzyme based on a single nucleotide polymorphism (SNP) (G177C) leading three phenotypes (ALAD1-1, ALAD1-2, and ALAD2-2). Previous studies have shown that this polymorphism is related to lead toxicity. There is little evidence showing interethnic differences in the distribution of this polymorphism. We examined the distribution of genetic variants of the ALAD G177C polymorphism in four Asians, three Africans, and three Mexicans. Genomic DNA was extracted from blood or bloodstain, and the genotypes for the ALAD polymorphism were determined by PCR followed by RFLP digestion and gel electrophoresis. We found a notable interethnic disparity in the distribution of ALAD G177C genotypes and alleles. The <span class="hlt">frequencies</span> of ALAD2 in Asian populations were comparable to those in Caucasians, while Africans had no mutation allele. These findings may help us understand the interethnic disparities in susceptibility to lead toxicity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3158940','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3158940"><span><span class="hlt">Frequency</span>-dependent <span class="hlt">variation</span> in mimetic fidelity in an intraspecific mimicry system</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Iserbyt, Arne; Bots, Jessica; Van Dongen, Stefan; Ting, Janice J.; Van Gossum, Hans; Sherratt, Thomas N.</p> <p>2011-01-01</p> <p>Contemporary theory predicts that the degree of mimetic similarity of mimics towards their model should increase as the mimic/model ratio increases. Thus, when the mimic/model ratio is high, then the mimic has to resemble the model very closely to still gain protection from the signal receiver. To date, empirical evidence of this effect is limited to a single example where mimicry occurs between species. Here, for the first time, we test whether mimetic fidelity varies with mimic/model ratios in an intraspecific mimicry system, in which signal receivers are the same species as the mimics and models. To this end, we studied a polymorphic damselfly with a single male phenotype and two female morphs, in which one morph resembles the male phenotype while the other does not. Phenotypic similarity of males to both female morphs was quantified using morphometric data for multiple populations with varying mimic/model ratios repeated over a 3 year period. Our results demonstrate that male-like females were overall closer in size to males than the other female morph. Furthermore, the extent of morphological similarity between male-like females and males, measured as Mahalanobis distances, was <span class="hlt">frequency</span>-dependent in the direction predicted. Hence, this study provides direct quantitative support for the prediction that the mimetic similarity of mimics to their models increases as the mimic/model ratio increases. We suggest that the phenomenon may be widespread in a range of mimicry systems. PMID:21367784</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://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/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/27821433','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27821433"><span>Wolbachia in the Drosophila yakuba Complex: Pervasive <span class="hlt">Frequency</span> <span class="hlt">Variation</span> and Weak Cytoplasmic Incompatibility, but No Apparent Effect on Reproductive Isolation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cooper, Brandon S; Ginsberg, Paul S; Turelli, Michael; Matute, Daniel R</p> <p>2017-01-01</p> <p>Three hybridizing species-the clade [(Drosophila yakuba, D. santomea), D. teissieri]-comprise the yakuba complex in the D. melanogaster subgroup. Their ranges overlap on Bioko and São Tomé, islands off west Africa. All three species are infected with Wolbachia-maternally inherited, endosymbiotic bacteria, best known for manipulating host reproduction to favor infected females. Previous analyses reported no cytoplasmic incompatibility (CI) in these species. However, we discovered that Wolbachia from each species cause intraspecific and interspecific CI. In D teissieri, analyses of F1 and backcross genotypes show that both host genotype and Wolbachia <span class="hlt">variation</span> modulate CI intensity. Wolbachia-infected females seem largely protected from intraspecific and interspecific CI, irrespective of Wolbachia and host genotypes. Wolbachia do not affect host mating behavior or female fecundity, within or between species. The latter suggests little apparent effect of Wolbachia on premating or gametic reproductive isolation (RI) between host species. In nature, Wolbachia <span class="hlt">frequencies</span> varied spatially for D. yakuba in 2009, with 76% (N = 155) infected on São Tomé, and only 3% (N = 36) infected on Bioko; <span class="hlt">frequencies</span> also varied temporally in D. yakuba and D. santomea on São Tomé between 2009 and 2015. These temporal <span class="hlt">frequency</span> fluctuations could generate asymmetries in interspecific mating success, and contribute to postzygotic RI. However, the fluctuations in Wolbachia <span class="hlt">frequencies</span> that we observe also suggest that asymmetries are unlikely to persist. Finally, we address theoretical questions that our empirical findings raise about Wolbachia persistence when conditions fluctuate, and about the stable coexistence of Wolbachia and host variants that modulate Wolbachia effects. Copyright © 2017 by the Genetics Society of America.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18033786','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18033786"><span><span class="hlt">Variation</span> in the mutation <span class="hlt">frequency</span> determining quinolone resistance in Chlamydia trachomatis serovars L2 and D.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rupp, Jan; Solbach, Werner; Gieffers, Jens</p> <p>2008-01-01</p> <p>Quinolone resistance of chlamydiae is supposed to be extremely rare. To assess the risk for the emergence of chlamydial quinolone resistance, we analysed the occurrence of resistant mutants in a quantitative perspective. Infectious elementary bodies of Chlamydia trachomatis serovar L(2) (ATCC VR-902B) and D (ATTC VR-885) clones were purified on density gradients, and mutants resistant to moxifloxacin and rifampicin were selected by a plaque assay. Plaque assays were conducted with 2 x 10(9) inclusion forming units (IFUs) of each serovar for rifampicin and 2.66 x 10(9) IFUs for moxifloxacin. Resistant clones were analysed for mutations in the gyrA, gyrB, parC and parE genes, and respective MICs were determined by titration experiments. Mutation <span class="hlt">frequencies</span> for rifampicin (MIC >or= 0.2 mg/L) did not differ significantly between serovars L(2) and D (5.7 x 10(-7) versus 6.3 x 10(-7)). In contrast, the occurrence of moxifloxacin-resistant mutants (MIC >or= 0.6 mg/L) was determined to be 2.0-2.2 x 10(-8) for the serovar L(2) isolate and less than 2.66 x 10(-9) for the serovar D isolate. Moxifloxacin resistance of all serovar L(2) clones depended on single-nucleotide point mutations in the quinolone resistance-determining region of the gyrA, whereas no additional mutations were found in the gyrB, parC or parE genes. C. trachomatis isolates have the potential to present with clinically relevant antibiotic resistance in future. Serovar-specific differences in the occurrence of spontaneous mutations should be taken into account to predict quinolone resistance in different chlamydial diseases.</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> </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://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('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.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('https://www.ncbi.nlm.nih.gov/pubmed/25491602','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25491602"><span>Geographical distribution and <span class="hlt">frequencies</span> of organophosphate-resistant Ace alleles and morphometric <span class="hlt">variations</span> in olive fruit fly populations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Doğaç, Ersin; Kandemir, İrfan; Taşkın, Vatan</p> <p>2015-11-01</p> <p>In the Mediterranean basin, organophosphate (OP) insecticides have been used intensively to control olive fly populations. Acetylcholinesterase (Ace) is the molecular target of OP insecticides, and three resistance-associated mutations that confer different levels of OP insensitivity have been identified. In this study, genotypes of olive fly Ace were determined in field-collected populations from broad geographical areas in Turkey. In addition, the levels of asymmetry of wing and leg characters were compared in these populations. Our study revealed the existence of a genetically smooth stratification pattern in OP resistance allele distribution in the olive fly populations of Turkey. In contrast to earlier findings, the <span class="hlt">frequency</span> of Δ3Q was found to be lower in the Aegean region, where the populations have been subjected to high selection pressure. Results based on the morphological differences among the samples revealed a similar pattern for both sides and did not demonstrate a clear <span class="hlt">separation</span>. The <span class="hlt">frequencies</span> and geographic range of resistance alleles indicate that they were selected in the Aegean coast of Turkey and then spread westward towards Europe. One possible explanation for the absence of morphological asymmetry in olive fly samples might be the presence of modifier allele(s) that compensate for the increase in asymmetry. © 2014 Society of Chemical Industry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5499255','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5499255"><span>Genetic <span class="hlt">Variation</span> and Its Reflection on Posttranslational Modifications in <span class="hlt">Frequency</span> Clock and Mating Type a-1 Proteins in Sordaria fimicola</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Arif, Rabia; Akram, Faiza; Jamil, Tazeen; Lee, Siu Fai</p> <p>2017-01-01</p> <p>Posttranslational modifications (PTMs) occur in all essential proteins taking command of their functions. There are many domains inside proteins where modifications take place on side-chains of amino acids through various enzymes to generate different species of proteins. In this manuscript we have, for the first time, predicted posttranslational modifications of <span class="hlt">frequency</span> clock and mating type a-1 proteins in Sordaria fimicola collected from different sites to see the effect of environment on proteins or various amino acids pickings and their ultimate impact on consensus sequences present in mating type proteins using bioinformatics tools. Furthermore, we have also measured and walked through genomic DNA of various Sordaria strains to determine genetic diversity by genotyping the short sequence repeats (SSRs) of wild strains of S. fimicola collected from contrasting environments of two opposing slopes (harsh and xeric south facing slope and mild north facing slope) of Evolution Canyon (EC), Israel. Based on the whole genome sequence of S. macrospora, we targeted 20 genomic regions in S. fimicola which contain short sequence repeats (SSRs). Our data revealed genetic <span class="hlt">variations</span> in strains from south facing slope and these findings assist in the hypothesis that genetic <span class="hlt">variations</span> caused by stressful environments lead to evolution. PMID:28717646</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28717646','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28717646"><span>Genetic <span class="hlt">Variation</span> and Its Reflection on Posttranslational Modifications in <span class="hlt">Frequency</span> Clock and Mating Type a-1 Proteins in Sordaria fimicola.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Arif, Rabia; Akram, Faiza; Jamil, Tazeen; Mukhtar, Hamid; Lee, Siu Fai; Saleem, Muhammad</p> <p>2017-01-01</p> <p>Posttranslational modifications (PTMs) occur in all essential proteins taking command of their functions. There are many domains inside proteins where modifications take place on side-chains of amino acids through various enzymes to generate different species of proteins. In this manuscript we have, for the first time, predicted posttranslational modifications of <span class="hlt">frequency</span> clock and mating type a-1 proteins in Sordaria fimicola collected from different sites to see the effect of environment on proteins or various amino acids pickings and their ultimate impact on consensus sequences present in mating type proteins using bioinformatics tools. Furthermore, we have also measured and walked through genomic DNA of various Sordaria strains to determine genetic diversity by genotyping the short sequence repeats (SSRs) of wild strains of S. fimicola collected from contrasting environments of two opposing slopes (harsh and xeric south facing slope and mild north facing slope) of Evolution Canyon (EC), Israel. Based on the whole genome sequence of S. macrospora, we targeted 20 genomic regions in S. fimicola which contain short sequence repeats (SSRs). Our data revealed genetic <span class="hlt">variations</span> in strains from south facing slope and these findings assist in the hypothesis that genetic <span class="hlt">variations</span> caused by stressful environments lead to evolution.</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.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3403690','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3403690"><span>School-Based Racial and Gender Discrimination among African American Adolescents: Exploring Gender <span class="hlt">Variation</span> in <span class="hlt">Frequency</span> and Implications for Adjustment</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chavous, Tabbye M.; Griffin, Tiffany M.</p> <p>2012-01-01</p> <p>The present study examined school-based racial and gender discrimination experiences among African American adolescents in Grade 8 (n = 204 girls; n = 209 boys). A primary goal was exploring gender <span class="hlt">variation</span> in <span class="hlt">frequency</span> of both types of discrimination and associations of discrimination with academic and psychological functioning among girls and boys. Girls and boys did not vary in reported racial discrimination <span class="hlt">frequency</span>, but boys reported more gender discrimination experiences. Multiple regression analyses within gender groups indicated that among girls and boys, racial discrimination and gender discrimination predicted higher depressive symptoms and school importance and racial discrimination predicted self-esteem. Racial and gender discrimination were also negatively associated with grade point average among boys but were not significantly associated in girls’ analyses. Significant gender discrimination X racial discrimination interactions resulted in the girls’ models predicting psychological outcomes and in boys’ models predicting academic achievement. Taken together, findings suggest the importance of considering gender- and race-related experiences in understanding academic and psychological adjustment among African American adolescents. PMID:22837794</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.ncbi.nlm.nih.gov/pubmed/28760406','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28760406"><span>The <span class="hlt">variation</span> in <span class="hlt">frequency</span> locations in Doppler ultrasound spectra for maximum blood flow velocities in narrowed vessels.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Yingyun; Zhang, Yufeng; Gao, Lian; Deng, Li; Hu, Xiao; Zhang, Kexin; Li, Haiyan</p> <p>2017-07-28</p> <p>This study assessed the <span class="hlt">variation</span> in the <span class="hlt">frequency</span> locations in the Doppler ultrasound spectra for the maximum blood flow velocities of in vessels with different degrees of bilaterally axisymmetric stenosis. This was done by comparing the relationship between the velocity distributions and corresponding Doppler power spectra. First, a geometric vessel model with axisymmetric stenosis was established. This made it possible to obtain the blood flow velocity distributions for different degrees of stenosis from the solutions of the Navier-Stokes equations. Then, the Doppler spectra were calculated for the entire segment of the vessel that was covered by the sound field. Finally, the maximum <span class="hlt">frequency</span> locations for the spectra were determined based on the intersections of the maximum values chosen from the calculated blood flow velocity distributions and their corresponding spectra. The computational analysis showed that the maximum <span class="hlt">frequencies</span>, which corresponded to the maximum blood flow velocities for different degrees of stenosis, were located at different positions along the spectral falling edges. The location for a normal (stenosis free) vessel was in the middle of the falling edge. For vessels with increasing degrees of stenosis, this location shifted approximately linearly downward along the falling edge. For 40% stenosis, the location reached a position at the falling edge of 0.32. Results obtained using the Field II simulation tool demonstrated the validity of the theoretical analysis and calculations, and may help to improve the maximum velocity estimation accuracy for Doppler blood flow spectra in stenosed vessels. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18986889','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18986889"><span>Reduction of influence of <span class="hlt">variation</span> in center <span class="hlt">frequencies</span> of RF echoes on estimation of artery-wall strain.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hasegawa, Hideyuki; Kanai, Hiroshi</p> <p>2008-09-01</p> <p>Atherosclerotic change of the arterial wall leads to a significant change in its elasticity. For assessment of elasticity, measurement of arterial wall deformation is required. For motion estimation, correlation techniques are widely used, and we have developed a phase-sensitive correlation method, namely, the phased-tracking method, to measure the regional strain of the arterial wall due to the heartbeat. Although phase-sensitive methods using demodulated complex signals require less computation in comparison with methods using the correlation between RF signals or iterative methods, the displacement estimated by such phase-sensitive methods are biased when the center <span class="hlt">frequency</span> of the RF echo apparently varies. One of the reasons for the apparent change in the center <span class="hlt">frequency</span> would be the interference of echoes from scatterers within the wall. In the present study, a method was introduced to reduce the influence of <span class="hlt">variation</span> in the center <span class="hlt">frequencies</span> of RF echoes on the estimation of the artery-wall strain when using the phase-sensitive correlation technique. The improvement in the strain estimation by the proposed method was validated using a phantom. The error from the theoretical strain profile and the standard deviation in strain estimated by the proposed method were 12.0% and 14.1%, respectively, significantly smaller than those (23.7% and 46.2%) obtained by the conventional phase-sensitive correlation method. Furthermore, in the preliminary in vitro experimental results, the strain distribution of the arterial wall well corresponded with pathology, i.e., the region with calcified tissue showed very small strain, and the region almost homogeneously composed of smooth muscle and collagen showed relatively larger strain and clear strain decay with respect to the radial distance from the lumen.</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('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('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('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/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/22884012','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22884012"><span>Influence of serotonin transporter promoter <span class="hlt">variation</span> on the effects of <span class="hlt">separation</span> from parent/partner on depression.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fandiño-Losada, Andrés; Wei, Yabin; Aberg, Elin; Sjöholm, Louise K; Lavebratt, Catharina; Forsell, Yvonne</p> <p>2013-01-25</p> <p>Loss of parent during childhood or loss of partner has been associated with adulthood depression. The serotonin transporter polymorphism (5-HTTLPR) has been reported to moderate stress sensitivity reflected for example in the relationship between childhood maltreatment and depression. Therefore, the effect of 5-HTT promoter <span class="hlt">variation</span> on the relationship between the loss of parent or partner and depression was examined. 411 depressive cases and 1347 control subjects from a large well-characterized longitudinal population-based sample of adult Swedes with data on life history and life situation, including psychiatric diagnostic instruments, were studied. Their DNA was genotyped for the mini-haplotype 5-HTTLPR-rs25531. Individuals with low 5-HTT activity variants had an increased risk of depression given loss of partner last year compared to those with high activity variants. Conversely, 5-HTT activity <span class="hlt">variation</span> appeared not to strongly influence the risk of depression given loss of parent during childhood. Small sample size for those with losses of both parent and partner. Limited power to detect small interaction effects. The increased risk of depression given last year loss of partner appeared to be influenced by genetic <span class="hlt">variation</span> regulating 5-HTT activity. This adds to previous findings of 5-HTT x stressful life events interactions on depression and is in agreement with stronger GxE effects when using objective environmental measures. Copyright © 2012 Elsevier B.V. All rights reserved.</p> </li> <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> </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://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('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('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/2012ClDy...39.2393W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ClDy...39.2393W"><span>Possible association of the western Tibetan Plateau snow cover with the decadal to interdecadal <span class="hlt">variations</span> of northern China heatwave <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; Jiang, Zhihong; Li, Jianping; Zhong, Shanshan; Wang, Lijuan</p> <p>2012-11-01</p> <p>Northern China has been subject to increased heatwave <span class="hlt">frequency</span> (HWF) in recent decades, which deteriorates the local droughts and desertification. More than half a billion people face drinking water shortages and worsening ecological environment. In this study, the variability in the western Tibetan Plateau snow cover (TPSC) is observed to have an intimate linkage with the first empirical orthogonal function mode of the summer HWF across China. This distinct leading mode is dominated by the decadal to inter-decadal variability and features a mono-sign pattern with the extreme value center prevailing over northern China and high pressure anomalies at mid- and upper troposphere over Mongolia and the adjacent regions. A simplified general circulation model is utilized to examine the possible physical mechanism. A reduced TPSC anomaly can induce a positive geopotential height anomaly at the mid- and upper troposphere and subsequently enhance the climatological high pressure ridge over Mongolia and the adjacent regions. The subsidence associated with the high pressure anomalies tends to suppress the local cloud formation, which increases the net radiation budget, heats the surface, and favors more heatwaves. On the other hand, the surface heating can excite high pressure anomalies at mid- and upper troposphere. The latter further strengthens the upper troposphere high pressure anomalies over Mongolia and the adjacent regions. Through such positive feedback effect, the TPSC is tied to the interdecadal <span class="hlt">variations</span> of the northern China HWF.</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> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810048729&hterms=322&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dp%25EF%25BF%25BD%2526%2523322','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810048729&hterms=322&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dp%25EF%25BF%25BD%2526%2523322"><span><span class="hlt">Separate</span> and combined effects of static stability and shear <span class="hlt">variation</span> on the baroclinic instability of a two-layer current</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hyun, J. M.</p> <p>1981-01-01</p> <p>Quasi-geostrophic disturbance instability characteristics are studied in light of a linearized, two-layer Eady model in which both the static stability and the zonal current shear are uniform but different in each layer. It is shown that the qualitative character of the instability is determined by the sign of the basic-state potential vorticity gradient at the layer interface, and that there is a qualitative similarity between the effects of Richardson number <span class="hlt">variations</span> due to changes in static stability and those due to changes in shear. The two-layer model is also used to construct an analog of the Williams (1974) continuous model of generalized Eady waves, the basic state in that case having zero potential vorticity gradient in the interior. The model results are in good agreement with the earlier Williams findings.</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://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('http://adsabs.harvard.edu/abs/2017EGUGA..19.2919S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.2919S"><span>Effect of low-<span class="hlt">frequency</span> and midrange <span class="hlt">variations</span> f the Earth's angular velocity on its seismic activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sasorova, Elena; Levin, Boris</p> <p>2017-04-01</p> <p>We used observational data on <span class="hlt">variations</span> in Earth's angular velocity duration of 296 years for the semi-annual time series of observations and seismic observations c 1720 to 2016. It was determined the value of the relative angular velocity of the Earth's rotation (v). Then by using band-pass filters were isolated the low-<span class="hlt">frequency</span> (Vn) and midrange (Vm) components from the v values (for the periods 124-19 years and 1.2 years-5 months accordingly). The analysis of the Vn value [Levin, Sasorova, 2015] shows, that the reduction of the angular velocity (deceleration) is accompanied by an increase in density of seismic events. The local minimums of the Vn value coincide with maximums of seismic activity. On the contrary the increase of the angular velocity (acceleration) accompanied by a decrease in the density of events. The angular speed of the Earth's rotation around its axis during the year varies, it determined by the values of Vm. Accelerated movement observed in the summer (June-July-August), braking - in the winter (October-November-December). Recently it was shown [Sasorova, Zhuravlev, 2006], that the irregularity in the distribution of seismic events during the year observed for several regions of the Pacific. This irregularity is statistically significant. The maximum of the seismic activity manifested mainly in the winter months (November - February). In this work it is shown that the within-year periodicity appears unstable, greatly amplified in some years and almost disappearing in others. A comparative analysis of the Vn values and the two-dimensional distributions of the seismic event density on the annual and monthly scale were carried out. As a result, it was noted that the within-year irregularity manifested mainly on the Earth's braking stages, and do not observed virtually at stages of acceleration. It should be noted that the Vn values vary from 3 to 5 (in relative units), and Vm from +0.8 to -1 (the difference is more than 4 times). Thus effect</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('https://www.ncbi.nlm.nih.gov/pubmed/28764638','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28764638"><span>Contribution of rare and low-<span class="hlt">frequency</span> whole-genome sequence variants to complex traits <span class="hlt">variation</span> in dairy cattle.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Qianqian; Calus, Mario P L; Guldbrandtsen, Bernt; Lund, Mogens Sandø; Sahana, Goutam</p> <p>2017-08-01</p> <p>Whole-genome sequencing and imputation methodologies have enabled the study of the effects of genomic variants with low to very low minor allele <span class="hlt">frequency</span> (MAF) on <span class="hlt">variation</span> in complex traits. Our objective was to estimate the proportion of variance explained by imputed sequence variants classified according to their MAF compared with the variance explained by the pedigree-based additive genetic relationship matrix for 17 traits in Nordic Holstein dairy cattle. Imputed sequence variants were grouped into seven classes according to their MAF (0.001-0.01, 0.01-0.05, 0.05-0.1, 0.1-0.2, 0.2-0.3, 0.3-0.4 and 0.4-0.5). The total contribution of all imputed sequence variants to variance in deregressed estimated breeding values or proofs (DRP) for different traits ranged from 0.41 [standard error (SE) = 0.026] for temperament to 0.87 (SE = 0.011) for milk yield. The contribution of rare variants (MAF < 0.01) to the total DRP variance explained by all imputed sequence variants was relatively small (a maximum of 12.5% for the health index). Rare and low-<span class="hlt">frequency</span> variants (MAF < 0.05) contributed a larger proportion of the explained DRP variances (>13%) for health-related traits than for production traits (<11%). However, a substantial proportion of these variance estimates across different MAF classes had large SE, especially when the variance explained by a MAF class was small. The proportion of DRP variance that was explained by all imputed whole-genome sequence variants improved slightly compared with variance explained by the 50 k Illumina markers, which are routinely used in bovine genomic prediction. However, the proportion of DRP variance explained by imputed sequence variants was lower than that explained by pedigree relationships, ranging from 1.5% for milk yield to 37.9% for the health index. Imputed sequence variants explained more of the variance in DRP than the 50 k markers for most traits, but explained less variance than that captured by pedigree</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('http://adsabs.harvard.edu/abs/2010AIPC.1211.1349H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AIPC.1211.1349H"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hillmann, S.; Heuer, H.; Robbert, A.; Baron, H.-U.; Bamberg, J.; Meyendorf, N.</p> <p>2010-02-01</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('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/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.ncbi.nlm.nih.gov/pubmed/18462314','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18462314"><span><span class="hlt">Variation</span> in sex ratio, morph-specific reproductive ecology and an experimental test of <span class="hlt">frequency</span>-dependence in the gynodioecious Kallstroemia grandiflora (Zygophyllaceae).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cuevas, E; Parker, I M; Molina-Freaner, F</p> <p>2008-07-01</p> <p>An enduring puzzle in gynodioecious species is the great <span class="hlt">variation</span> in female <span class="hlt">frequency</span> seen among populations. We quantified sex ratio in 44 populations of gynodioecious Kallstroemia grandiflora. Then, we measured pollinator visitation, pollen deposition, autonomous selfing rate and pollen limitation of females. Finally, using experimental populations, we tested whether female fitness responds to the <span class="hlt">frequency</span> of female plants. We found broad variability in sex ratio among populations (0-44% female). Hermaphrodite flowers received more pollinator visits and pollen grains than females, and bagged hermaphrodite flowers produced fruits. However, we found no evidence of pollen limitation in females. In experimental populations, female plants showed no evidence of <span class="hlt">frequency</span>-dependent pollinator visitation, fruit set, seed set or total seed mass. These results do not support <span class="hlt">frequency</span>-dependent <span class="hlt">variation</span> in fitness as a major mechanism affecting female <span class="hlt">frequencies</span> in K. grandiflora. Within the context of this study, pollinators are abundant and pollinator movement appears to operate at a large enough scale to overcome the potential reproductive disadvantages of producing solely female flowers.</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. © 2015 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.</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/25005760','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25005760"><span>Is there seasonal <span class="hlt">variation</span> in symptom severity, uroflowmetry and <span class="hlt">frequency</span>-volume chart parameters in men with lower urinary tract symptoms?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cartwright, Rufus; Mariappan, Paramananthan; Turner, Kevin J; Stewart, Laurence H; Rajan, Prabhakar</p> <p>2014-08-01</p> <p>There is a widely held perception that lower urinary tract symptoms may be exacerbated by cold weather. In this study, we examine the effect of seasonal <span class="hlt">variation</span> in ambient temperatures on <span class="hlt">frequency</span>-volume chart derivatives, symptom severity scores and uroflowmetry parameters in men with lower urinary tract symptom. Between January 2000 and April 2004, men presenting with lower urinary tract symptom were prospectively recruited and assessed in Edinburgh, UK (55°52'N) with maritime temperate climates (Köppen classification Cfb). Local monthly temperatures were extracted from national meteorological records. Patients completed the International Prostate Symptom Score and 3-day <span class="hlt">frequency</span> volume chart before undergoing free uroflowmetry with post-micturition volume measurement. Exclusion criteria were previous bladder outflow surgery and anti-cholinergic medication. Data on 296 patients were suitable for analysis. Mean age was 62.3 years (range, 26-90). Over the period of study, the coldest month was January (mean = 4.7℃) and the warmest month was August (mean = 15.8℃). There was no significant <span class="hlt">variation</span> in either International Prostate Symptom Score symptom scores by season (p > 0.05) or any <span class="hlt">frequency</span>-volume chart parameters, with the exception on an increase in median actual nightly voids over the summer months (p = 0.021). There was no significant correlation between maximal flow rate and post-micturition residual volumes and mean monthly temperatures (p > 0.05). Seasonal <span class="hlt">variation</span> in nocturia, but not other <span class="hlt">frequency</span>-volume parameters, symptom severity or uroflowmetry parameters, is significant in men with lower urinary tract symptom. Future work should consider the impact of seasonal <span class="hlt">variation</span> in lower urinary tract symptoms in both sexes across a wider range of climates. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.</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> </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://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.ncbi.nlm.nih.gov/pubmed/28764478','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28764478"><span><span class="hlt">Variation</span> in echolocation call <span class="hlt">frequencies</span> in two species of free-tailed bats according to temperature and humidity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chaverri, Gloriana; Quirós, Oscar E</p> <p>2017-07-01</p> <p>Bats can actively adjust their echolocation signals to specific habitats and tasks, yet it is not known if bats also modify their calls to decrease atmospheric attenuation. Here the authors test the hypothesis that individuals emit echolocation calls ideally suited to current conditions of temperature and humidity. The authors recorded two species, Molossus molossus and Molossops temminckii, in the field under different conditions of humidity and temperature. For each species, two calls were analyzed: the shorter <span class="hlt">frequency</span> modulated (FM) signals that bats emitted as they approached the recording microphone, and the longer constant <span class="hlt">frequency</span> (CF) calls emitted thereafter. For each signal, the authors extracted peak <span class="hlt">frequency</span> and duration, and compared these parameters among species, call type, and environmental conditions. The authors' results show significant differences in peak <span class="hlt">frequency</span> and duration among environmental conditions for both call types. Bats decreased the <span class="hlt">frequency</span> and increased duration of CF calls as atmospheric attenuation increased; using a lower-<span class="hlt">frequency</span> call may increase the range of detection by a few meters as atmospheric attenuation increases. The same trend was not observed for FM calls, which may be explained by the primary role of these signals in short-range target localization.</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('https://www.ncbi.nlm.nih.gov/pubmed/28127254','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28127254"><span>Genetic <span class="hlt">separation</span> of southern and northern soybean breeding programs in North America and their associated allelic <span class="hlt">variation</span> at four maturity loci.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wolfgang, Goettel; An, Yong-Qiang Charles</p> <p>2017-01-01</p> <p>North American soybean breeders have successfully developed a large number of elite cultivars with diverse maturity groups (MG) from a small number of ancestral landraces. To understand molecular and genetic basis underlying the large <span class="hlt">variation</span> in their maturity and flowering times, we integrated pedigree and maturity data of 166 cultivars representing North American soybean breeding. Network analysis and visualization of their pedigree relationships revealed a clear <span class="hlt">separation</span> of southern and northern soybean breeding programs, suggesting that little genetic exchange occurred between northern (MG 0-IV) and southern cultivars (MG V-VIII). We also analyzed the transcript sequence and expression levels of four major maturity genes (E1 to E4) and revealed their allelic variants in 75 major ancestral landraces and milestone cultivars. We observed that e1-as was the predominant e mutant allele in northern genotypes, followed by e2 and e3. There was no allelic <span class="hlt">variation</span> at E4. Transcript accumulation of the e2 mutant allele was significantly reduced, which might be caused by its premature stop codon triggering the nonsense-mediated mRNA decay pathway. The large DNA deletion generating the e3 mutant allele also created a gene fusion transcript. The e alleles found in milestone cultivars were traced through pedigrees to their ancestral landraces and geographic origins. Our analysis revealed an approximate correlation between dysfunctional alleles and maturity groups for most of the 75 cultivars. However, single e mutant alleles and their combinations were not sufficient to fully explain their maturity diversity, suggesting that additional genes/alleles are likely involved in regulating maturity time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12803910','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12803910"><span><span class="hlt">Frequency</span>-dependent <span class="hlt">variation</span> in reproductive success in Narcissus: implications for the maintenance of stigma-height dimorphism.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thompson, John D; Barrett, Spencer C H; Baker, Angela M</p> <p>2003-05-07</p> <p>Negative <span class="hlt">frequency</span>-dependent selection is a major selective force maintaining sexual polymorphisms. However, empirical demonstrations of <span class="hlt">frequency</span>-dependent reproductive success are rare, particularly in plants. We investigate this problem by manipulating the <span class="hlt">frequencies</span> of style morphs in a natural population of Narcissus assoanus, a self-incompatible herb with style-length dimorphism and intra-morph compatibility. We predicted that the reproductive success of morphs would vary negatively with their <span class="hlt">frequency</span> because of the effects of morph-specific differences in sex-organ position on patterns of pollen transfer. This prediction was generally supported. The fruit and seed set of the two morphs did not differ significantly in plots with 1 : 1 morph ratios. However, short-styled plants produced significantly fewer seeds than long-styled plants in monomorphic plots, and significantly more seeds than long-styled plants in plots with 'long-biased' morph ratios. These patterns indicate that in the absence of physiological barriers to intra-morph mating, negative <span class="hlt">frequency</span>-dependent selection contributes to the maintenance of stylar polymorphism through inter-morph pollen transfer. Our experimental results also provide insights into the mechanisms governing the biased style-morph ratios in populations of Narcissus species.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1691332','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1691332"><span><span class="hlt">Frequency</span>-dependent <span class="hlt">variation</span> in reproductive success in Narcissus: implications for the maintenance of stigma-height dimorphism.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Thompson, John D; Barrett, Spencer C H; Baker, Angela M</p> <p>2003-01-01</p> <p>Negative <span class="hlt">frequency</span>-dependent selection is a major selective force maintaining sexual polymorphisms. However, empirical demonstrations of <span class="hlt">frequency</span>-dependent reproductive success are rare, particularly in plants. We investigate this problem by manipulating the <span class="hlt">frequencies</span> of style morphs in a natural population of Narcissus assoanus, a self-incompatible herb with style-length dimorphism and intra-morph compatibility. We predicted that the reproductive success of morphs would vary negatively with their <span class="hlt">frequency</span> because of the effects of morph-specific differences in sex-organ position on patterns of pollen transfer. This prediction was generally supported. The fruit and seed set of the two morphs did not differ significantly in plots with 1 : 1 morph ratios. However, short-styled plants produced significantly fewer seeds than long-styled plants in monomorphic plots, and significantly more seeds than long-styled plants in plots with 'long-biased' morph ratios. These patterns indicate that in the absence of physiological barriers to intra-morph mating, negative <span class="hlt">frequency</span>-dependent selection contributes to the maintenance of stylar polymorphism through inter-morph pollen transfer. Our experimental results also provide insights into the mechanisms governing the biased style-morph ratios in populations of Narcissus species. PMID:12803910</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.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('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=3928360','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3928360"><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="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</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. PMID:24558468</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('https://eric.ed.gov/?q=second+AND+language+AND+acquisition+AND+children&pg=4&id=EJ1130009','ERIC'); return false;" href="https://eric.ed.gov/?q=second+AND+language+AND+acquisition+AND+children&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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4314442','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4314442"><span>The Tracking Study: Description of a randomized controlled trial of <span class="hlt">variations</span> on weight tracking <span class="hlt">frequency</span> in a behavioral weight loss program</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Linde, Jennifer A.; Jeffery, Robert W.; Crow, Scott J.; Brelje, Kerrin L.; Pacanowski, Carly R.; Gavin, Kara L.; Smolenski, Derek J.</p> <p>2014-01-01</p> <p>Observational evidence from behavioral weight control trials and community studies suggests that greater <span class="hlt">frequency</span> of weighing oneself, or tracking weight, is associated with better weight outcomes. Conversely, it has also been suggested that frequent weight tracking may have a negative impact on mental health and outcomes during weight loss, but there are minimal experimental data that address this concern in the context of an active weight loss program. To achieve the long-term goal of strengthening behavioral weight loss programs, the purpose of this randomized controlled trial (the Tracking Study) is to test <span class="hlt">variations</span> on <span class="hlt">frequency</span> of self-weighing during a behavioral weight loss program, and to examine psychosocial and mental health correlates of weight tracking and weight loss outcomes. Three hundred thirty-nine overweight and obese adults were recruited and randomized to one of three <span class="hlt">variations</span> on weight tracking <span class="hlt">frequency</span> during a 12-month weight loss program with a 12-month follow-up: daily weight tracking, weekly weight tracking, or no weight tracking. The primary outcome is weight in kilograms at 24 months. The weight loss program integrates each weight tracking instruction with standard behavioral weight loss techniques (goal setting, self-monitoring, stimulus control, dietary and physical activity enhancements, lifestyle modifications); participants in weight tracking conditions were provided with wireless Internet technology (Wi-Fi-enabled digital scales and touchscreen personal devices) to facilitate weight tracking during the study. This paper describes the study design, intervention features, recruitment, and baseline characteristics of participants enrolled in the Tracking Study. PMID:25533727</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> <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://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('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="http://www.dtic.mil/">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> </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('https://www.fs.usda.gov/treesearch/pubs/12819','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/12819"><span><span class="hlt">Variation</span> in pin knot <span class="hlt">frequency</span> in black walnut lumber cut from a small provenance/progeny test</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Peter Y. S. Chen; Robert E. Bodkin; J. W. Van Sambeek</p> <p>1995-01-01</p> <p>This small study examined the <span class="hlt">frequency</span> of knots (> 1 growth ring), pin knots (latent or suppressed buds), and pin knot clusters in 414 black walnut (Juglans nigra L.) lumber from 42 logs. 18 to 21 cm dbh, cut from a 14-year-old provenance/progeny test. Two boards from opposite sides of each log were analyzed for number of knots, pin knots, and...</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('https://www.ncbi.nlm.nih.gov/pubmed/27108409','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27108409"><span><span class="hlt">Frequency</span> of rare mutations and common genetic <span class="hlt">variations</span> in severe hypertriglyceridemia in the general population of Spain.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lamiquiz-Moneo, Itziar; Blanco-Torrecilla, Cristian; Bea, Ana M; Mateo-Gallego, Rocío; Pérez-Calahorra, Sofía; Baila-Rueda, Lucía; Cenarro, Ana; Civeira, Fernando; de Castro-Orós, Isabel</p> <p>2016-04-23</p> <p>Hypertriglyceridemia (HTG) is a common complex metabolic trait that results of the accumulation of relatively common genetic variants in combination with other modifier genes and environmental factors resulting in increased plasma triglyceride (TG) levels. The majority of severe primary hypertriglyceridemias is diagnosed in adulthood and their molecular bases have not been fully defined yet. The prevalence of HTG is highly variable among populations, possibly caused by differences in environmental factors and genetic background. However, the prevalence of very high TG and the <span class="hlt">frequency</span> of rare mutations causing HTG in a whole non-selected population have not been previously studied. The total of 23,310 subjects over 18 years from a primary care-district in a middle-class area of Zaragoza (Spain) with TG >500 mg/dL were selected to establish HTG prevalence. Those affected of primary HTG were considered for further genetic analysis. The promoters, coding regions and exon-intron boundaries of LPL, LMF1, APOC2, APOA5, APOE and GPIHBP1 genes were sequenced. The <span class="hlt">frequency</span> of rare variants identified was studied in 90 controls. One hundred ninety-four subjects (1.04%) had HTG and 90 subjects (46.4%) met the inclusion criteria for primary HTG. In this subgroup, nine patients (12.3%) were carriers of 7 rare variants in LPL, LMF1, APOA5, GPIHBP1 or APOE genes. Three of these mutations are described for the first time in this work. The presence of a rare pathogenic mutation did not confer a differential phenotype or a higher family history of HTG. The prevalence of rare mutations in candidate genes in subjects with primary HTG is low. The low <span class="hlt">frequency</span> of rare mutations, the absence of a more severe phenotype or the dominant transmission of the HTG would not suggest the use of genetic analysis in the clinical practice in this population.</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.ncbi.nlm.nih.gov/pubmed/22988957','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22988957"><span>Actin filament motility induced <span class="hlt">variation</span> of resonance <span class="hlt">frequency</span> and rigidity of polymer surfaces studied by quartz crystal microbalance.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>van Zalinge, Harm; Aveyard, Jenny; Hajne, Joanna; Persson, Malin; Mansson, Alf; Nicolau, Dan V</p> <p>2012-10-23</p> <p>This contribution reports on the quantification of the parameters of the motility assays for actomyosin system using a quartz crystal microbalance (QCM). In particular, we report on the difference in the observed resonance <span class="hlt">frequency</span> and dissipation of a quartz crystal when actin filaments are stationary as opposed to when they are motile. The changes in QCM measurements were studied for various polymer-coated surfaces functionalized with heavy meromyosin (HMM). The results of the QCM experiments show that the HMM-induced sliding velocity of actin filaments is modulated by a combination of the viscoelastic properties of the polymer layer including the HMM motors.</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/26507110','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26507110"><span>Solidago altissima differs with respect to ploidy <span class="hlt">frequency</span> and clinal <span class="hlt">variation</span> across the prairie-forest biome border in Minnesota.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Etterson, Julie R; Toczydlowski, Rachel H; Winkler, Katharine J; Kirschbaum, Jessica A; McAulay, Tim S</p> <p>2016-01-01</p> <p>Although our awareness of ploidy diversity has expanded with the application of flow cytometry, we still know little about the extent to which cytotypes within mixed-ploidy populations are genetically differentiated across environmental gradients. To address this issue, we reared 14 populations of Solidago altissima spanning the prairie-forest ecotone in Minnesota in a common garden with a watering treatment. We assessed ploidy <span class="hlt">frequencies</span> and measured survival, flowering phenology, and plant architectural traits for 4 years. All populations harbored multiple cytotypes; prairie populations were dominated by tetraploids, forest populations by hexaploids. Diploids and polyploids differed significantly for 84% of the traits. Beyond average differences, the slope of trait values covaried with latitude and longitude, but this relationship was stronger for diploids than the other two polyploid cytotypes as indicated by numerous ploidy × latitude and ploidy × longitude interactions. For example, the timing of flowering of the cytotypes overlapped in populations sampled from the northeastern hemiboreal forest but differed significantly between cytotypes sampled from populations in the southwestern prairie. The watering treatments had weak effects, and there were no ploidy differences for phenotypic plasticity. Our data show that diploids have diverged genetically to a greater extent than polyploids along the environmental clines sampled in this study. Moreover, different environments favor phenotypic convergence over divergence among cytotypes for some traits. Differences in ploidy <span class="hlt">frequency</span> and phenotypic divergence among cytotypes across gradients of temperature and precipitation are important considerations for restoration in an age of climate change. © 2016 Botanical Society of America.</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.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('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('https://www.ncbi.nlm.nih.gov/pubmed/25392761','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25392761"><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="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Amos, William; 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3737181','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3737181"><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="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>McMahan, Susan; Kohl, Kathryn P.; Sekelsky, Jeff</p> <p>2013-01-01</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. PMID:23797104</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24080066','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24080066"><span>Seasonal <span class="hlt">variation</span> in the <span class="hlt">frequency</span> of sudden cardiac death and ventricular tachyarrhythmia in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy: the effect of meteorological factors.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chung, Fa-Po; Li, Hsin-Ru; Chong, Eric; Pan, Chih-Hsin; Lin, Yenn-Jiang; Chang, Shih-Lin; Lo, Li-Wei; Hu, Yu-Feng; Tuan, Ta-Chuan; Chao, Tze-Fan; Liao, Jo-nan; Lin, Wen-Yu; Shaw, Kai-Ping; Chen, Shih-Ann</p> <p>2013-12-01</p> <p>Sudden cardiac death (SCD) is the most catastrophic presentation in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). To investigate the seasonal <span class="hlt">variations</span> in the <span class="hlt">frequency</span> of SCD and ventricular tachyarrhythmia in patients with AVRD/C and to elucidate the meteorological factors that trigger these events. From 1998 to 2012, we enrolled 88 consecutive patients with ARVD/C from Taipei City. The cohort included 20 living patients who received implantable cardioverter-defibrillator (ICD) and 68 autopsied patients with SCD from the Taiwan National Forensic Institute registry. The baseline clinical characteristics, seasonal distribution, and associated meteorological factors were explored to predict the occurrences of events, which include appropriate ICD interventions and SCD. There were 106 events, including 38 (35.8%, 1.9 episodes per patient) appropriate ICD interventions in living patients with ARVD/C and 68 (64.2%) SCD events. The seasonal peak occurred predominantly in summer (P < .05) in both groups. For meteorological factors, the onset of event was associated with higher average daily temperature and longer sunshine duration. The <span class="hlt">variation</span> in humidity within 3 days of events was significantly increased. After multivariate logistic regression analysis, higher average daily temperature and larger <span class="hlt">variation</span> in humidity were associated with increase in events (odds ratio 1.23, 95% confidence interval 1.16-1.31, P < .001, and odds ratio 1.19, 95% confidence interval 1.15-1.23, P < .001, respectively). There was seasonal <span class="hlt">variation</span> with a summer peak in the occurrence of ventricular arrhythmias and SCD in patients with ARVD/C. Meteorological factors including higher temperature and larger <span class="hlt">variation</span> in humidity within 3 days of events were independently associated with the development of events. © 2013 Heart Rhythm Society Published by Heart Rhythm Society All rights reserved.</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('https://www.ncbi.nlm.nih.gov/pubmed/16381944','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16381944"><span>SNP500Cancer: a public resource for sequence validation, assay development, and <span class="hlt">frequency</span> analysis for genetic <span class="hlt">variation</span> in candidate genes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Packer, Bernice R; Yeager, Meredith; Burdett, Laura; Welch, Robert; Beerman, Michael; Qi, Liqun; Sicotte, Hugues; Staats, Brian; Acharya, Mekhala; Crenshaw, Andrew; Eckert, Andrew; Puri, Vinita; Gerhard, Daniela S; Chanock, Stephen J</p> <p>2006-01-01</p> <p>The SNP500Cancer database provides sequence and genotype assay information for candidate SNPs useful in mapping complex diseases, such as cancer. The database is an integral component of the NCI Cancer Genome Anatomy Project (http://cgap.nci.nih.gov). SNP500Cancer reports sequence analysis of anonymized control DNA samples (n = 102 Coriell samples representing four self-described ethnic groups: African/African-American, Caucasian, Hispanic and Pacific Rim). The website is searchable by gene, chromosome, gene ontology pathway, dbSNP ID and SNP500Cancer SNP ID. As of October 2005, the database contains >13 400 SNPs, 9124 of which have been sequenced in the SNP500Cancer population. For each analysed SNP, gene location and >200 bp of surrounding annotated sequence (including nearby SNPs) are provided, with <span class="hlt">frequency</span> information in total and per subpopulation as well as calculation of Hardy-Weinberg equilibrium for each subpopulation. The website provides the conditions for validated sequencing and genotyping assays, as well as genotype results for the 102 samples, in both viewable and downloadable formats. A subset of sequence validated SNPs with minor allele <span class="hlt">frequency</span> >5% are entered into a high-throughput pipeline for genotyping analysis to determine concordance for the same 102 samples. In addition, the results of genotype analysis for select validated SNP assays (defined as 100% concordance between sequence analysis and genotype results) are posted for an additional 280 samples drawn from the Human Diversity Panel (HDP). SNP500Cancer provides an invaluable resource for investigators to select SNPs for analysis, design genotyping assays using validated sequence data, choose selected assays already validated on one or more genotyping platforms, and select reference standards for genotyping assays. The SNP500Cancer database is freely accessible via the web page at http://snp500cancer.nci.nih.gov.</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('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('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/19902245','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19902245"><span>High <span class="hlt">frequency</span> of HMW-GS sequence <span class="hlt">variation</span> through somatic hybridization between Agropyron elongatum and common wheat.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gao, Xin; Liu, Shu Wei; Sun, Qun; Xia, Guang Min</p> <p>2010-01-01</p> <p>A symmetric somatic hybridization was performed to combine the protoplasts of tall wheatgrass (Agropyron elongatum) and bread wheat (Triticum aestivum). Fertile regenerants were obtained which were morphologically similar to tall wheatgrass, but which contained some introgression segments from wheat. An SDS-PAGE analysis showed that a number of non-parental high-molecular weight glutenin subunits (HMW-GS) were present in the symmetric somatic hybridization derivatives. These sequences were amplified, cloned and sequenced, to deliver 14 distinct HMW-GS coding sequences, eight of which were of the y-type (Hy1-Hy8) and six x-type (Hx1-Hx6). Five of the cloned HMW-GS sequences were successfully expressed in E. coli. The analysis of their deduced peptide sequences showed that they all possessed the typical HMW-GS primary structure. Sequence alignments indicated that Hx5 and Hy1 were probably derived from the tall wheatgrass genes Aex5 and Aey6, while Hy2, Hy3, Hx1 and Hy6 may have resulted from slippage in the replication of a related biparental gene. We found that both symmetric and asymmetric somatic hybridization could promote the emergence of novel alleles. We discussed the origination of allelic <span class="hlt">variation</span> of HMW-GS genes in somatic hybridization, which might be the result from the response to genomic shock triggered by the merger and interaction of biparent genomes.</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('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://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=3726542','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3726542"><span>Free-Ranging Male Koalas Use Size-Related <span class="hlt">Variation</span> in Formant <span class="hlt">Frequencies</span> to Assess Rival Males</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Charlton, Benjamin D.; Whisson, Desley A.; Reby, David</p> <p>2013-01-01</p> <p>Although the use of formant <span class="hlt">frequencies</span> in nonhuman animal vocal communication systems has received considerable recent interest, only a few studies have examined the importance of these acoustic cues to body size during intra-sexual competition between males. Here we used playback experiments to present free-ranging male koalas with re-synthesised bellow vocalisations in which the formants were shifted to simulate either a large or a small adult male. We found that male looking responses did not differ according to the size variant condition played back. In contrast, male koalas produced longer bellows and spent more time bellowing when they were presented with playbacks simulating larger rivals. In addition, males were significantly slower to respond to this class of playback stimuli than they were to bellows simulating small males. Our results indicate that male koalas invest more effort into their vocal responses when they are presented with bellows that have lower formants indicative of larger rivals, but also show that males are slower to engage in vocal exchanges with larger males that represent more dangerous rivals. By demonstrating that male koalas use formants to assess rivals during the breeding season we have provided evidence that male-male competition constitutes an important selection pressure for broadcasting and attending to size-related formant information in this species. Further empirical studies should investigate the extent to which the use of formants during intra-sexual competition is widespread throughout mammals. PMID:23922967</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.G21B0451D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.G21B0451D"><span>Low-<span class="hlt">Frequency</span> Ocean Bottom Pressure <span class="hlt">Variations</span> in the North Pacific in Response to Time-Variable Surface Winds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dobslaw, H.; Petrick, C.; Bergmann-Wolf, I.; Matthes, K. B.; Thomas, M.</p> <p>2014-12-01</p> <p>One decade of time-variable gravity field observations from the GRACE satellite mission reveals low-<span class="hlt">frequency</span> ocean bottom pressure (OBP) variability of up to 2.5 hPa centered at the northern flank of the subtropical gyre in the North Pacific. From a 145 year-long simulation with a coupled chemistry climate model, OBP variability is found to be related to the prevailing atmospheric sea-level pressure and surface wind conditions in the larger North Pacific area. The dominating atmospheric pressure patterns obtained from the climate model run allow in combination with ERA-Interim sea-level pressure and surface winds a reconstruction of the OBP variability in the North Pacific from atmospheric model data only, which correlates favourably (r=0.7) with GRACE ocean bottom pressure observations. The regression results indicate that GRACE-based OBP observations are indeed sensitive to changes in the prevailing sea-level pressure and thus surface wind conditions in the North Pacific, thereby opening opportunities to constrain atmospheric models from satellite gravity observations over the oceans.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23922967','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23922967"><span>Free-ranging male koalas use size-related <span class="hlt">variation</span> in formant <span class="hlt">frequencies</span> to assess rival males.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Charlton, Benjamin D; Whisson, Desley A; Reby, David</p> <p>2013-01-01</p> <p>Although the use of formant <span class="hlt">frequencies</span> in nonhuman animal vocal communication systems has received considerable recent interest, only a few studies have examined the importance of these acoustic cues to body size during intra-sexual competition between males. Here we used playback experiments to present free-ranging male koalas with re-synthesised bellow vocalisations in which the formants were shifted to simulate either a large or a small adult male. We found that male looking responses did not differ according to the size variant condition played back. In contrast, male koalas produced longer bellows and spent more time bellowing when they were presented with playbacks simulating larger rivals. In addition, males were significantly slower to respond to this class of playback stimuli than they were to bellows simulating small males. Our results indicate that male koalas invest more effort into their vocal responses when they are presented with bellows that have lower formants indicative of larger rivals, but also show that males are slower to engage in vocal exchanges with larger males that represent more dangerous rivals. By demonstrating that male koalas use formants to assess rivals during the breeding season we have provided evidence that male-male competition constitutes an important selection pressure for broadcasting and attending to size-related formant information in this species. Further empirical studies should investigate the extent to which the use of formants during intra-sexual competition is widespread throughout mammals.</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> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JAESc.147..193M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JAESc.147..193M"><span>Spatial <span class="hlt">variation</span> in the <span class="hlt">frequency</span>-magnitude distribution of earthquakes under the tectonic framework in the Middle East</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mousavi, S. Mostafa</p> <p>2017-10-01</p> <p>Spatial <span class="hlt">variations</span> of seismic energy released and b-value over the Middle East region are investigated based on a seismicity catalog from 1995 to 2007. The goal is to use these seismic parameters and based on other geodetic and geophysical observations, such as GPS measurements, strain rate model, fault distribution, focal mechanism, crustal model, Q model, and gravity measurements, etc., to uncover spatial patterns that seem anomalous. Areas of high energy released (cumulative) seem to correspond to the areas of relatively high b-values. Areas of high energy released and high b-values seem to correspond very well with the location of continental collision where earthquake activities are high. The divergent boundary between Arabia and African plates and subduction zone at Makran seem to correspond to low to moderate energy release. Northern Pamir, Azerbaijan-Caucasus, the lower part of Zagros Mountains, eastern Turkey, Owen Fracture Zone, Strait of Bob-el-Mandeb, and south of the Sulaiman Shear Zone seem to correspond to high cumulative energy-released, high strain rate, high b-values, and high fault density. While, the central and eastern Iran, southern Zagros, northern Pakistan, Gulf of Aden, Alborz, southwest of the Caspian Sea, western Caucasus and Kopeh-Dagh seem to correspond with lower b-values. The cross-section map for Hindu-Kush shows general decreasing of the b-values with depth, however, a region of high b-value is observed underneath Pamir at depths from 170 to 230 km. This anomaly region can be due to dehydration of Pamir crustal slab at depth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28582450','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28582450"><span>Spontaneous low <span class="hlt">frequency</span> BOLD signal <span class="hlt">variations</span> from resting-state fMRI are decreased in Alzheimer disease.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kazemifar, Samaneh; Manning, Kathryn Y; Rajakumar, Nagalingam; Gómez, Francisco A; Soddu, Andrea; Borrie, Michael J; Menon, Ravi S; Bartha, Robert</p> <p>2017-01-01</p> <p>Previous studies have demonstrated altered brain activity in Alzheimer's disease using task based functional MRI (fMRI), network based resting-state fMRI, and glucose metabolism from 18F fluorodeoxyglucose-PET (FDG-PET). Our goal was to define a novel indicator of neuronal activity based on a first-order textural feature of the resting state functional MRI (RS-fMRI) signal. Furthermore, we examined the association between this neuronal activity metric and glucose metabolism from 18F FDG-PET. We studied 15 normal elderly controls (NEC) and 15 probable Alzheimer disease (AD) subjects from the AD Neuroimaging Initiative. An independent component analysis was applied to the RS-fMRI, followed by template matching to identify neuronal components (NC). A regional brain activity measurement was constructed based on the <span class="hlt">variation</span> of the RS-fMRI signal of these NC. The standardized glucose uptake values of several brain regions relative to the cerebellum (SUVR) were measured from partial volume corrected FDG-PET images. Comparing the AD and NEC groups, the mean brain activity metric was significantly lower in the accumbens, while the glucose SUVR was significantly lower in the amygdala and hippocampus. The RS-fMRI brain activity metric was positively correlated with cognitive measures and amyloid β1-42 cerebral spinal fluid levels; however, these did not remain significant following Bonferroni correction. There was a significant linear correlation between the brain activity metric and the glucose SUVR measurements. This proof of concept study demonstrates that this novel and easy to implement RS-fMRI brain activity metric can differentiate a group of healthy elderly controls from a group of people with AD.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5459336','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5459336"><span>Spontaneous low <span class="hlt">frequency</span> BOLD signal <span class="hlt">variations</span> from resting-state fMRI are decreased in Alzheimer disease</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Manning, Kathryn Y.; Rajakumar, Nagalingam; Gómez, Francisco A.; Soddu, Andrea; Borrie, Michael J.</p> <p>2017-01-01</p> <p>Previous studies have demonstrated altered brain activity in Alzheimer's disease using task based functional MRI (fMRI), network based resting-state fMRI, and glucose metabolism from 18F fluorodeoxyglucose-PET (FDG-PET). Our goal was to define a novel indicator of neuronal activity based on a first-order textural feature of the resting state functional MRI (RS-fMRI) signal. Furthermore, we examined the association between this neuronal activity metric and glucose metabolism from 18F FDG-PET. We studied 15 normal elderly controls (NEC) and 15 probable Alzheimer disease (AD) subjects from the AD Neuroimaging Initiative. An independent component analysis was applied to the RS-fMRI, followed by template matching to identify neuronal components (NC). A regional brain activity measurement was constructed based on the <span class="hlt">variation</span> of the RS-fMRI signal of these NC. The standardized glucose uptake values of several brain regions relative to the cerebellum (SUVR) were measured from partial volume corrected FDG-PET images. Comparing the AD and NEC groups, the mean brain activity metric was significantly lower in the accumbens, while the glucose SUVR was significantly lower in the amygdala and hippocampus. The RS-fMRI brain activity metric was positively correlated with cognitive measures and amyloid β1–42 cerebral spinal fluid levels; however, these did not remain significant following Bonferroni correction. There was a significant linear correlation between the brain activity metric and the glucose SUVR measurements. This proof of concept study demonstrates that this novel and easy to implement RS-fMRI brain activity metric can differentiate a group of healthy elderly controls from a group of people with AD. PMID:28582450</p> </li> <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=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.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.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/2017ClDy..tmp..671L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy..tmp..671L"><span>Modulation of the atmospheric quasi-biweekly oscillation on the diurnal <span class="hlt">variation</span> of the occurrence <span class="hlt">frequency</span> of the Tibetan Plateau vortices</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Lun; Zhang, Renhe; Wen, Min</p> <p>2017-09-01</p> <p>In this study, modulation of the atmospheric quasi-biweekly oscillation (QBWO) on diurnal <span class="hlt">variation</span> of the occurrence <span class="hlt">frequency</span> of Tibetan Plateau vortices (TPVs) during May-August of 2000-2009 was investigated. The diurnal <span class="hlt">variations</span> of the occurrence <span class="hlt">frequency</span> of the TPVs (OFTPVs) and the related dynamic and thermodynamic features in the positive and negative phases of QBWO were compared. In both the positive and negative phases, the OFTPVs reaches the maximum from evening to midnight (18-00 LT, LT indicates the local time), and minimum from early morning to noon (06-12 LT). At 18 LT, there is strongest convergence at 500 hPa and ascending motion, as well as the most abundant net water vapor budget over the Tibetan Plateau, which is in favor of the precipitation and the related condensation latent heat release, corresponding to the maximum of OFTPVs in 18-00 LT. On the contrary, in the early morning at 06 LT, the conditions are most unfavorable for genesis of TPVs in 06-12 LT. QBWO leads to stronger convergence at 500 hPa, ascending motion as well as more massive water vapor in the positive phases than those in the negative phases, resulting in larger numbers of TPVs occur in all of the four periods of a day (00-06 LT, 06-12 LT, 12-18 LT, and 18-00 LT) in the former. The TPVs generating from the early morning to noon (06-12 LT) are weaker and more sensitive and fragile to the disadvantageous background, while the TPVs occurring from evening to midnight (18-00 LT) are stronger and seem to be well tolerated, leading to more remarkable contrast between the OFTPVs in the negative and positive phases in 06-12 LT than in 18-00 LT.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10441353','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10441353"><span>Determination of a biological absorber depth utilizing multiple source-detector <span class="hlt">separations</span> and multiple <span class="hlt">frequency</span> values of near-infrared time-resolved spectroscopy</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hemelt; Kang</p> <p>1999-07-01</p> <p>Visualization of the photon path in scattering media is attempted through the use of <span class="hlt">frequency</span> response analysis of near-infrared time-resolved spectroscopy (NIR-TRS) spectra. The effect of the source-detector distances and the modulation <span class="hlt">frequency</span> on the photon path is examined. It was found that the use of multifrequency information could lead to the possibility of obtaining the information of an absorber's depth without increasing the number of measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25500224','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25500224"><span>Two <span class="hlt">separable</span> mechanisms are responsible for mental stress effects on high <span class="hlt">frequency</span> heart rate variability: an intra-individual approach in a healthy and a diabetic sample.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kuehl, Linn K; Deuter, Christian E; Richter, Steffen; Schulz, André; Rüddel, Heinz; Schächinger, Hartmut</p> <p>2015-03-01</p> <p>Central withdrawal of parasympathetic cardiac control and increased respiratory <span class="hlt">frequency</span> represent two important determinants of reduced respiratory-related heart rate variability (HRV). However, studies are missing to disentangle their relative contribution during mental stress. Healthy subjects (n=10) and type 2 diabetic patients (n=8), the latter with evidence of cardiac autonomic neuropathy, participated in this study. Using an intra-individual approach, high-<span class="hlt">frequency</span> (hf) HRV was assessed for spontaneous (during rest and mental stress) and paced breathing (0.15, 0.2, 0.25, 0.3, 0.35, 0.4 and 0.45 Hz; randomized sequence). Mental stress was induced by a challenging reaction time task. Effects of respiratory <span class="hlt">frequency</span> on hf HRV were individually predicted by paced breathing data. Mental stress decreased hf HRV (p<.001), and increased respiratory <span class="hlt">frequency</span> (p=.01). Individual prediction of hf HRV by stress respiratory <span class="hlt">frequency</span> resulted in lower values (p=.02) than observed during rest, indicating that respiratory stress effects were sufficient to reduce hf HRV. However, observed hf HRV values during stress were even lower (p<.001). These results indicate that hf HRV reductions during stress can only partly be explained by concomitant respiratory <span class="hlt">frequency</span> changes. This effect is detectable in healthy subjects and in patients with evidence of diabetic cardiac autonomic neuropathy. Copyright © 2014 Elsevier B.V. All rights reserved.</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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5549512','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5549512"><span>What is the <span class="hlt">frequency</span> of anatomical <span class="hlt">variations</span> and pathological findings in maxillary sinuses among patients subjected to maxillofacial cone beam computed tomography? A systematic review</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Diago-Vilalta, Jose-Vicente; Melo, María; Bagán, Leticia; Soldini, Maria-Costanza; Di-Nardo, Chiara; Ata-Ali, Fadi; Mañes-Ferrer, José-Félix</p> <p>2017-01-01</p> <p>Background When considering dental implant rehabilitation in atrophic posterior sectors, the maxillary sinuses must be evaluated in detail. Knowledge of the anatomical <span class="hlt">variations</span> and of the potential lesions found in these structures conditions the outcome of sinus lift procedures and therefore of the dental implants. A systematic review is made to determine the <span class="hlt">frequency</span> of anatomical <span class="hlt">variations</span> and pathological findings in maxillary sinuses among patients subjected to cone beam computed tomography (CBCT). Material and Methods A PubMed (MEDLINE) literature search was made of articles published up until 20 December 2015. The systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). The quality of the studies included in the review was assessed using the Methodological Index for Nonrandomized Studies (MINORS). Results The combinations of search terms resulted in a list of 3482 titles. Twenty-three studies finally met the inclusion criteria and were entered in the systematic review, comprising a total of 11,971 patients. The most common anatomical <span class="hlt">variations</span> were pneumatization and sinus septa. The prevalence of maxillary sinus disease ranged from 7.5% to 66%. The most common pathological findings of the maxillary sinus were mucosal thickening, sinusitis and sinus opacification. Conclusions Although the main indication of CBCT of the maxillary sinus in dentistry is sinus floor elevation/treatment planning and evaluation prior to dental implant placement, this imaging modality is increasingly also used for endodontic and periodontal purposes. There is no consensus regarding the cutoff point beyond which mucosal thickening of the maxillary sinus should be regarded as pathological, and the definition of maxillary sinusitis moreover varies greatly in the scientific literature. In this regard, international consensus is required in relation to these concepts, with a clear distinction between healthy and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28619514','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28619514"><span>The <span class="hlt">frequency</span> of Th17 cells in the small intestine exhibits a day-night <span class="hlt">variation</span> dependent on circadian clock activity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thu Le, Ha Pham; Nakamura, Yuki; Oh-Oka, Kyoko; Ishimaru, Kayoko; Nakajima, Shotaro; Nakao, Atsuhito</p> <p>2017-08-19</p> <p>Interleukin-17-producing CD4(+) T helper (Th17) cells are a key immune lineage that protects against bacterial and fungal infections at mucosal surfaces. At steady state, Th17 cells are abundant in the small intestinal mucosa of mice. There are several mechanisms for regulating the population of Th17 cells in the small intestine, reflecting the importance of maintaining their numbers in the correct balance. Here we demonstrate the existence of a time-of-day-dependent <span class="hlt">variation</span> in the <span class="hlt">frequency</span> of Th17 cells in the lamina propria of the small intestine in wild-type mice, which was not observed in mice with a loss-of-function mutation of the core circadian gene Clock or in mice housed under aberrant light/dark conditions. Consistent with this, expression of CCL20, a chemokine that regulates homeostatic trafficking of Th17 cells to the small intestine, exhibited circadian rhythms in the small intestine of wild-type, but not Clock-mutated, mice. In support of these observations, the magnitude of ovalbumin (OVA)-specific antibody and T-cell responses in mice sensitized with OVA plus cholera toxin, a mucosal Th17 cell-dependent adjuvant, was correlated with daily <span class="hlt">variations</span> in the proportion of Th17 cells in the small intestine. These results suggest that the proportion of Th17 cells in the small intestine exhibits a day-night <span class="hlt">variation</span> in association with CCL20 expression, which depends on circadian clock activity. The findings provide novel insight into the regulation of the Th17 cell population in the small intestine at steady state, which may have translational potential for mucosal vaccination strategies. Copyright © 2017 Elsevier Inc. All rights reserved.</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/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('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('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://adsabs.harvard.edu/abs/2016AIPC.1737d0005P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1737d0005P"><span>Kerosene-water <span class="hlt">separation</span> in T-junction with orientation upward branch with a 60° angle: <span class="hlt">Variation</span> of diameter ratio</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Puspitasari, Dewi; Indarto, Purnomo, Khasani</p> <p>2016-06-01</p> <p>Research on the T-junction is still underway for the flow of liquid-liquid (kerosene-water). Some research on the characteristics of kerosene-water <span class="hlt">separation</span> was performed using T-junction oriented upward branch with a 60° angle. To observe the effect of diameters ratio on the phase <span class="hlt">separation</span> that produced T-junction then made a test section with a horizontal pipe diameter 36 mm, while the side arm 36 mm diameter, 26 mm and 19 mm (diameters ratio of 1, 0.7 and 0.5) by using plexiglass pipe type. Based on experimental results and visualization of data flow in the test section, to the value obtained 60% water cut, the maximum <span class="hlt">separation</span> efficiency of 94%, FK = 0.94 and FW = 0.001 with a diameter ratio of 1. For other diameter ratio of 0.7 and 0.5 respectively <span class="hlt">separation</span> efficiency of 66%, FK = 1 and Fw = 0.34 for 0.7 and <span class="hlt">separation</span> efficiency of 84%, FK = 1 and Fw = 0.16 for 0.5, the best value is obtained at a water cut 60% too. All the best conditions to achieve the above-stratified flow pattern.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27091582','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27091582"><span>Correlated inter-regional <span class="hlt">variations</span> in low <span class="hlt">frequency</span> local field potentials and resting state BOLD signals within S1 cortex of monkeys.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wilson, George H; Yang, Pai-Feng; Gore, John C; Chen, Li Min</p> <p>2016-08-01</p> <p>The hypothesis that specific <span class="hlt">frequency</span> components of the spontaneous local field potentials (LFPs) underlie low <span class="hlt">frequency</span> fluctuations of resting state fMRI (rsfMRI) signals was tested. The previous analyses of rsfMRI signals revealed differential inter-regional correlations among areas 3a, 3b, and 1 of primary somatosensory cortex (S1) in anesthetized monkeys (Wang et al. [2013]: Neuron 78:1116-1126). Here LFP band(s) which correlated between S1 regions, and how these inter-regional correlation differences covaried with rsfMRI signals were examined. LFP signals were filtered into seven bands (delta, theta, alpha, beta, gamma low, gamma high, and gamma very high), and then a Hilbert transformation was applied to obtain measures of instantaneous amplitudes and temporal lags between regions of interest (ROI) digit-digit pairs (areas 3b-area 1, area 3a-area 1, area 3a-area 3b) and digit-face pairs (area 3b-face, area 1-face, and area 3a-face). It was found that <span class="hlt">variations</span> in the inter-regional correlation strengths between digit-digit and digit-face pairs in the delta (1-4 Hz), alpha (9-14 Hz), beta (15-30 Hz), and gamma (31-50 Hz) bands parallel those of rsfMRI signals to varying degrees. Temporal lags between digit-digit area pairs varied across LFP bands, with area 3a mostly leading areas 1/2 and 3b. In summary, the data demonstrates that the low and middle <span class="hlt">frequency</span> range (1-50 Hz) of spontaneous LFP signals similarly covary with the low <span class="hlt">frequency</span> fluctuations of rsfMRI signals within local circuits of S1, supporting a neuronal electrophysiological basis of rsfMRI signals. Inter-areal LFP temporal lag differences provided novel insights into the directionality of information flow among S1 areas at rest. Hum Brain Mapp 37:2755-2766, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.</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('https://www.ncbi.nlm.nih.gov/pubmed/24965792','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24965792"><span>Intravesical TRPV4 blockade reduces repeated <span class="hlt">variate</span> stress-induced bladder dysfunction by increasing bladder capacity and decreasing voiding <span class="hlt">frequency</span> in male rats.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Merrill, Liana; Vizzard, Margaret A</p> <p>2014-08-15</p> <p>Individuals with functional lower urinary tract disorders including interstitial cystitis (IC)/bladder pain syndrome (BPS) and overactive bladder (OAB) often report symptom (e.g., urinary <span class="hlt">frequency</span>) worsening due to stress. One member of the transient receptor potential ion channel vanilloid family, TRPV4, has recently been implicated in urinary bladder dysfunction disorders including OAB and IC/BPS. These studies address the role of TRPV4 in stress-induced bladder dysfunction using an animal model of stress in male rats. To induce stress, rats were exposed to 7 days of repeated <span class="hlt">variate</span> stress (RVS). Quantitative PCR data demonstrated significant (P ≤ 0.01) increases in TRPV4 transcript levels in urothelium but not detrusor smooth muscle. Western blot analyses of split urinary bladders (i.e., urothelium and detrusor) showed significant (P ≤ 0.01) increases in TRPV4 protein expression levels in urothelial tissues but not detrusor smooth muscle. We previously showed that RVS produces bladder dysfunction characterized by decreased bladder capacity and increased voiding <span class="hlt">frequency</span>. The functional role of TRPV4 in RVS-induced bladder dysfunction was evaluated using continuous, open outlet intravesical infusion of saline in conjunction with administration of a TRPV4 agonist, GSK1016790A (3 μM), a TRPV4 antagonist, HC067047 (1 μM), or vehicle (0.1% DMSO in saline) in control and RVS-treated rats. Bladder capacity, void volume, and intercontraction interval significantly decreased following intravesical instillation of GSK1016790A in control rats and significantly (P ≤ 0.01) increased following administration of HC067047 in RVS-treated rats. These results demonstrate increased TRPV4 expression in the urothelium following RVS and that TRPV4 blockade ameliorates RVS-induced bladder dysfunction consistent with the role of TRPV4 as a promising target for bladder function disorders. Copyright © 2014 the American Physiological Society.</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.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('https://www.ncbi.nlm.nih.gov/pubmed/28956572','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28956572"><span>Theoretically unraveling the <span class="hlt">separation</span> of Am(iii)/Eu(iii): insights from mixed N,O-donor ligands with <span class="hlt">variations</span> of central heterocyclic moieties.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wu, Qun-Yan; Song, Yu-Ting; Ji, Lin; Wang, Cong-Zhi; Chai, Zhi-Fang; Shi, Wei-Qun</p> <p>2017-09-28</p> <p>With the fast development of nuclear energy, the issue related to spent nuclear fuel reprocessing has been regarded as an imperative task, especially for the <span class="hlt">separation</span> of minor actinides. In fact, it still remains a worldwide challenge to <span class="hlt">separate</span> trivalent An(iii) from Ln(iii) because of their similar chemical properties. Therefore, understanding the origin of extractant selectivity for the <span class="hlt">separation</span> of An(iii)/Ln(iii) by using theoretical methods is quite necessary. In this work, three ligands with similar structures but different bridging frameworks, Et-Tol-DAPhen (La), Et-Tol-BPyDA (Lb) and Et-Tol-PyDA (Lc), have been investigated and compared using relativistic density functional theory. The electrostatic potential and molecular orbitals of the ligands indicate that ligand La is a better electron donor compared to ligands Lb and Lc. The results of QTAIM, NOCV and NBO suggest that the Am-N bonds in the studied complexes have more covalent character compared to the Eu-N bonds. Based on the thermodynamic analysis, [M(NO3)(H2O)8](2+) + L + 2NO3(-) = [ML(NO3)3] + 8H2O should be the most probable reaction in the solvent extraction system. Our results clearly verify that the relatively harder oxygen atoms offer these ligands higher coordination affinities toward both of the An(iii) and Ln(iii) ions compared to the relatively softer nitrogen atoms. However, the latter possess stronger affinities toward An(iii) over Ln(iii), which partly results in the selectivity of these ligands. This work can afford useful information on achieving efficient An(iii)/Ln(iii) <span class="hlt">separation</span> through tuning the structural rigidity and hardness or softness of the functional moieties of the ligands.</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.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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3534777','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3534777"><span><span class="hlt">Separable</span> Processes Before, During, and After the N400 Elicited by Previously Inferred and New Information: Evidence from Time-<span class="hlt">Frequency</span> Decompositions</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Steele, Vaughn R.; Bernat, Edward M.; van den Broek, Paul; Collins, Paul F.; Patrick, Christopher J.; Marsolek, Chad J.</p> <p>2012-01-01</p> <p>Successful comprehension during reading often requires inferring information not explicitly presented. This information is readily accessible when subsequently encountered, and a neural correlate of this is an attenuation of the N400 event-related potential (ERP). We used ERPs and time-<span class="hlt">frequency</span> (TF) analysis to investigate neural correlates of processing inferred information after a causal coherence inference had been generated during text comprehension. Participants read short texts, some of which promoted inference generation. After each text, they performed lexical decisions to target words that were unrelated or inference-related to the preceding text. Consistent with previous findings, inference-related words elicited an attenuated N400 relative to unrelated words. TF analyses revealed unique contributions to the N400 from activity occurring at 1–6 Hz (theta) and 0–2 Hz (delta), supporting the view that multiple, sequential processes underlie the N400. PMID:23165117</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.B34B..07F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.B34B..07F"><span>High-Resolution Paleotempestology: Proxy Models for Reconstructing Interannual-Decadal <span class="hlt">Variations</span> in Pre-Historic Tropical Cyclone <span class="hlt">Frequency</span> and Intensity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frappier, A. B.; Sahagian, D.; Carpenter, S. J.; Gonz lez, L. A.; Frappier, B. R.</p> <p>2005-12-01</p> <p>Tropical cyclones (including hurricanes, typhoons, and cyclones) are among the most deadly and destructive natural hazards. As coastal populations and infrastructure in affected areas grow, the impact of these storms is sure to increase. On the other hand, the impact of global climate change on tropical cyclone activity remains uncertain and highly controversial. Recent research suggests that the destructive power of tropical cyclones in the Atlantic and north Pacific has increased substantially in recent decades in response to global warming. Related work also suggests that global tropical cyclone activity may be an important feedback mechanism in the planetary heat transport system that works to stabilize tropical temeratures and de-stabilize polar temperatures. In this century, climate change scenarios project that ocean-atmosphere conditions will become increasingly different from the 20th century for which the best historial and meteorological records of tropical cyclones are available. Geo-biologic proxies for paleotempestology can extend the historical record of tropical cyclone activity, enabling hypothesis testing across a wider array of climate boundary conditions. We present a 23-year tropical stalagmite record of recent stable isotope <span class="hlt">variations</span> at monthly-weekly temporal resolution contains abrupt low excursions in the stable oxygen isotope ratio (δ18O value) of calcite that correspond temporally with recent historical tropical cyclones in the vicinity of the cave. Using logistic regression, we developed a statistical model to detect the proxy signature of tropical cyclone precipitation events in high-resolution speleothem stable isotope records can be used to reconstruct interannual-decadal <span class="hlt">variations</span> in pre-historic storm <span class="hlt">frequency</span>. The model reliably identified eight of the ten historically known tropical cyclone proxy signals in this record using the measurable parameters δ18O value, δ13C value, and single point changes in δ18O value; the model</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('https://www.ncbi.nlm.nih.gov/pubmed/9430762','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9430762"><span>Role of fundamental <span class="hlt">frequency</span> differences in the perceptual <span class="hlt">separation</span> of competing vowel sounds by listeners with normal hearing and listeners with hearing loss.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Arehart, K H; King, C A; McLean-Mudgett, K S</p> <p>1997-12-01</p> <p>This study compared the ability of listeners with normal hearing and listeners with moderate to moderately-severe sensorineural hearing loss to use fundamental <span class="hlt">frequency</span> differences (delta F0) in the identification of monotically presented simultaneous vowels. Two psychophysical procedures, double vowel identification and masked vowel identification, were used to measure identification performance as a function of delta F0 (0 through 8 semitones) between simultaneous vowels. Performance in the double vowel identification task was measured by the percentage of trials in which listeners correctly identified both vowels in a double vowel. The masked vowel identification task yielded thresholds representing signal-to-noise ratios at which listeners could just identify target vowels in the presence of a masking vowel. In the double vowel identification task, both listeners with normal hearing and listeners with hearing loss showed significant delta F0 benefit: Between 0 and 2 semitones, listeners with normal hearing showed an 18.5% average increase in performance; listeners with hearing loss showed a 16.5% average increase. In the masked vowel identification task, both groups showed significant delta F0 benefit. However, the mean benefit associated with delta F0 differences in the masked vowel task was more than twice as large in listeners with normal hearing (9.4 dB) when compared to listeners with hearing loss (4.4 dB), suggesting less delta F0 benefit in listeners with hearing loss. In both tasks, overall performance of listeners with hearing loss was significantly worse than performance of listeners with normal hearing. Possible reasons for reduced delta F0 benefit and decreased overall performance in listeners with hearing loss include reduced audibility of vowel sounds and deficits in spectro-temporal processing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.5169S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.5169S"><span><span class="hlt">Separation</span> of climate- and geology-induced <span class="hlt">variations</span> in the hydrological response of a regional karstified aquifer: determination of a geologic transfer function</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Slimani, S.; Massei, N.; Dupont, J.-P.; Mesquita, J.; Laignel, B.</p> <p>2009-04-01</p> <p>Worldwide, karst hydrosystems represent a great potential in terms of water ressources. However, such heterogenous systems are characterized by a highly non-linear response to input signals. In the region of Upper Normandy (Northwestern France), where almost 100% of drinking water supply comes from ground water, the Chalk karst aquifer is characterized by the presence of a thick surficial formations cover which is unequally distributed over the area according to the regional geological context. This structural context also implies a significant spatial variability of the aquifer thickness. To assess the overall hydrologic variability of this aquifer, we use long-term hydraulic head and precipitation time series (20 years) to analyse their relationships according to such specific geological conditions. By continuous wavelet transform, the hydraulic head time series were found to exhibit long-term <span class="hlt">variations</span> that represented a great amount of variance in some locations, what we could eventually relate to climate-induced oscillations. This was particularly the case of those locations where the aquifer thickness was important. The climate-induced oscillations found were of the order of 2-3-yr and 5-6-yr which would well correspond to some modes of oscillation linked to the positive/negative regimes of the North Atlantic Oscillation. In addition, the corresponding <span class="hlt">variations</span> in hydrological time series exhibited a clear increase in the explanation of total variance from the early 90's up to the end of the series. In a second time, in order to assess the role of the geological medium in the precipitation/head relationship, we proposed to filter out those long-term spectral components inherent to climate fluctuations. This allowed identification of the head response to precipitation throughout the entire 20-yr period of study for short-term infra-annual time scales. Cross-correlation between the input and output signals after filtering out of long-term components showed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4450440','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4450440"><span>Use of a Novel Cell Adhesion Method and Digital Measurement to Show Stimulus-dependent <span class="hlt">Variation</span> in Somatic and Oral Ciliary Beat <span class="hlt">Frequency</span> in Paramecium</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Bell, Wade E.; Hallworth, Richard; Wyatt, Todd A.; Sisson, Joseph H.</p> <p>2015-01-01</p> <p>When Paramecium encounters positive stimuli, the membrane hyperpolarizes and ciliary beat <span class="hlt">frequency</span> increases. We adapted an established immobilization protocol using a biological adhesive and a novel digital analysis system to quantify beat <span class="hlt">frequency</span> in immobilized Paramecium. Cells showed low mortality and demonstrated beat <span class="hlt">frequencies</span> consistent with previous studies. Chemoattractant molecules, reduction in external potassium, and posterior stimulation all increased somatic beat <span class="hlt">frequency</span>. In all cases, the oral groove cilia maintained a higher beat <span class="hlt">frequency</span> than mid-body cilia, but only oral cilia from cells stimulated with chemoattactants showed an increase from basal levels. PMID:25066640</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25066640','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25066640"><span>Use of a novel cell adhesion method and digital measurement to show stimulus-dependent <span class="hlt">variation</span> in somatic and oral ciliary beat <span class="hlt">frequency</span> in Paramecium.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bell, Wade E; Hallworth, Richard; Wyatt, Todd A; Sisson, Joseph H</p> <p>2015-01-01</p> <p>When Paramecium encounters positive stimuli, the membrane hyperpolarizes and ciliary beat <span class="hlt">frequency</span> increases. We adapted an established immobilization protocol using a biological adhesive and a novel digital analysis system to quantify beat <span class="hlt">frequency</span> in immobilized Paramecium. Cells showed low mortality and demonstrated beat <span class="hlt">frequencies</span> consistent with previous studies. Chemoattractant molecules, reduction in external potassium, and posterior stimulation all increased somatic beat <span class="hlt">frequency</span>. In all cases, the oral groove cilia maintained a higher beat <span class="hlt">frequency</span> than mid-body cilia, but only oral cilia from cells stimulated with chemoattactants showed an increase from basal levels. © 2014 The Author(s) Journal of Eukaryotic Microbiology © 2014 International Society of Protistologists.</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://www.osti.gov/scitech/servlets/purl/6013362','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6013362"><span>Neptunium <span class="hlt">separations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wild, J.F.</p> <p>1983-05-09</p> <p>Two procedures for the <span class="hlt">separation</span> of Np are presented; the first involves <span class="hlt">separation</span> of /sup 239/Np from irradiated /sup 238/U, and the second involves <span class="hlt">separation</span> of /sup 237/Np from a solution representing that from a dissolved fuel element.</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('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://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('http://hdl.handle.net/2060/19930011381','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930011381"><span>Acoustophoresis <span class="hlt">separation</span> method</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Heyman, Joseph S. (Inventor)</p> <p>1993-01-01</p> <p>A method and apparatus are provided for acoustophoresis, i.e., the <span class="hlt">separation</span> of species via acoustic waves. An ultrasonic transducer applies an acoustic wave to one end of a sample container containing at least two species having different acoustic absorptions. The wave has a <span class="hlt">frequency</span> tuned to or harmonized with the point of resonance of the species to be <span class="hlt">separated</span>. This wave causes the species to be driven to an opposite end of the sample container for removal. A second ultrasonic transducer may be provided to apply a second, oppositely directed acoustic wave to prevent undesired streaming. In addition, a radio <span class="hlt">frequency</span> tuned to the mechanical resonance and coupled with a magnetic field can serve to identify a species in a medium comprising species with similar absorption coefficients, whereby an acoustic wave having a <span class="hlt">frequency</span> corresponding to this gyrational rate can then be applied to sweep the identified species to one end of the container for removal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/24061','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/24061"><span>Cover/<span class="hlt">Frequency</span> (CF)</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>John F. Caratti</p> <p>2006-01-01</p> <p>The FIREMON Cover/<span class="hlt">Frequency</span> (CF) method is used to assess changes in plant species cover and <span class="hlt">frequency</span> for a macroplot. This method uses multiple quadrats to sample within-plot <span class="hlt">variation</span> and quantify statistically valid changes in plant species cover, height, and <span class="hlt">frequency</span> over time. Because it is difficult to estimate cover in quadrats for larger plants, this method...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4252958','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4252958"><span>CENTRIFUGAL <span class="hlt">SEPARATORS</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Skarstrom, C.</p> <p>1959-03-10</p> <p>A centrifugal <span class="hlt">separator</span> is described for <span class="hlt">separating</span> gaseous mixtures where the temperature gradients both longitudinally and radially of the centrifuge may be controlled effectively to produce a maximum <span class="hlt">separation</span> of the process gases flowing through. Tbe invention provides for the balancing of increases and decreases in temperature in various zones of the centrifuge chamber as the result of compression and expansions respectively, of process gases and may be employed effectively both to neutralize harmful temperature gradients and to utilize beneficial temperaturc gradients within the centrifuge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22596658','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22596658"><span><span class="hlt">Frequency</span> spirals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ottino-Löffler, Bertrand; Strogatz, Steven H.</p> <p>2016-09-15</p> <p>We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “<span class="hlt">frequency</span> spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial <span class="hlt">variation</span> of the oscillators' instantaneous <span class="hlt">frequencies</span>, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, <span class="hlt">frequency</span> spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest <span class="hlt">frequency</span> spiral and characterize its properties using analytical and numerical methods. Simulations show that <span class="hlt">frequency</span> spirals in large lattices behave much like this simple prototype.</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.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('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> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21207949','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21207949"><span>Hg{sup +} <span class="hlt">frequency</span> standards</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Prestage, John D.; Tjoelker, Robert L.; Maleki, Lute</p> <p>1999-01-15</p> <p>In this paper we review the development of Hg{sup +} 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 3x10{sup -14}/{radical}{tau} when a cryogenic oscillator of stability 2-3x10{sup -15} was used as the local oscillator. The trapped ion <span class="hlt">frequency</span> standard employs a {sup 202}Hg discharge lamp to optically pump the trapped {sup 199}Hg{sup +} clock ions and a helium buffer gas to cool the ions to near room temperature. We describe a small Hg{sup +} 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{sup -12}, the 2{sup nd} 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{sup -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{sup 2}/2{pi}hc, at the level of 10{sup -20}/year as predicted in some Grand Unified String Theories.</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/25976931','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25976931"><span>Seasonal <span class="hlt">variation</span> in onset and relapse of IBD and a model to predict the <span class="hlt">frequency</span> of onset, relapse, and severity of IBD based on artificial neural network.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Peng, Jiang Chen; Ran, Zhi Hua; Shen, Jun</p> <p>2015-09-01</p> <p>Previous research has yielded conflicting data as to whether the natural history of inflammatory bowel disease follows a seasonal pattern. The purpose of this study was (1) to determine whether the <span class="hlt">frequency</span> of onset and relapse of inflammatory bowel disease follows a seasonal pattern and (2) to establish a model to predict the <span class="hlt">frequency</span> of onset, relapse, and severity of inflammatory bowel disease (IBD) with meteorological data based on artificial neural network (ANN). Patients with diagnosis of ulcerative colitis (UC) or Crohn's disease (CD) between 2003 and 2011 were investigated according to the occurrence of onset and flares of symptoms. The expected onset or relapse was calculated on a monthly basis over the study period. For artificial neural network (ANN), patients from 2003 to 2010 were assigned as training cohort and patients in 2011 were assigned as validation cohort. Mean square error (MSE) and mean absolute percentage error (MAPE) were used to evaluate the predictive accuracy. We found no seasonal pattern of onset (P = 0.248) and relapse (P = 0.394) among UC patients. But, the onset (P = 0.015) and relapse (P = 0.004) of CD were associated with seasonal pattern, with a peak in July and August. ANN had average accuracy to predict the <span class="hlt">frequency</span> of onset (MSE = 0.076, MAPE = 37.58%) and severity of IBD (MSE = 0.065, MAPE = 42.15%) but high accuracy in predicting the <span class="hlt">frequency</span> of relapse of IBD (MSE = 0.009, MAPE = 17.1%). The <span class="hlt">frequency</span> of onset and relapse in IBD showed seasonality only in CD, with a peak in July and August, but not in UC. ANN may have its value in predicting the <span class="hlt">frequency</span> of relapse among patients with IBD.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017RuPhJ..60..803R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017RuPhJ..60..803R"><span>Dielectric Properties of Marsh Vegetation in a <span class="hlt">Frequency</span> Range of 0.1-18 GHz Under <span class="hlt">Variation</span> of Temperature and Moisture</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Romanov, A. N.; Kochetkova, T. D.; Suslyaev, V. I.; Shcheglova, A. S.</p> <p>2017-09-01</p> <p>Dielectric characteristics of some species of marsh vegetation: lichen Cladonia stellaris (Opiz) Pouzar, moss Sphagnum, and a representative of Bryidae mosses - Dicranum polysetum are studied in the <span class="hlt">frequency</span> range from 100 MHz to 18 GHz. At a <span class="hlt">frequency</span> of 1.41 GHz, the influence of temperature in the range from -12 to +20°C on the behavior of dielectric characteristics of mosses, lichens, and peat is studied. The dependences of the dielectric characteristics of vegetation on the volumetric wetness are established.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/49883','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/49883"><span>Introduction to natural disturbances and historic range of <span class="hlt">variation</span>: type, <span class="hlt">frequency</span>, severity, and post-disturbance structure in central hardwood forests</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Katie Greenberg; Beverly S. Collins; Henry McNab; Douglas K. Miller; Gary R. Wein</p> <p>2015-01-01</p> <p>EXCERPT FROM: Natural Disturbances and Historic Range <span class="hlt">Variation</span> 2015. Throughout the history of upland hardwood forests of the Central Hardwood Region, natural disturbances have been integral to shaping forest structure and composition, and essential in maintaining diverse biotic...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15737128','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15737128"><span>Basic investigation of the lectin method for <span class="hlt">separation</span> and recovery of nucleated red blood cells in maternal blood, and a study into the <span class="hlt">frequency</span> of nucleated red blood cells in fetomaternal disorders.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ikeya, Miki; Shinya, Masaru; Kitagawa, Michihiro</p> <p>2005-03-01</p> <p>We previously reported the <span class="hlt">separation</span> and recovery of nucleated red blood cells (NRBCs) in maternal blood using the lectin method. In the present study, we verified the lectin method and investigated the appearance of NRBCs during pregnancy. For the concentration of lectin soy bean agglutinin, 7 mL of maternal peripheral blood was collected from 20 subjects, and the relative fluorescence intensity was measured using flowcytometry; 50 mg/mL, used in previous studies, was the optimal concentration. The number of cells recovered at each step of the lectin method was also investigated by FACS using fluorescence-labeled CD11a and CD33, and the results showed the usefulness of the method. Next, 7 mL of maternal peripheral blood was collected from 292 women with a normal single pregnancy (389 specimens), and NRBCs were <span class="hlt">separated</span> and recovered using the lectin method. NRBCs slightly increased over the course of pregnancy (y = 4.29x + 5.03, r2 = 0.11). When blood was collected multiple times in the same subjects, NRBCs increased in 63 of 77 subjects (83.1%, percent change: 2.4 +/- 19.0). No NRBCs were recovered in 17 subjects (4.7%). Regarding the relationship between fetomaternal disorders and the <span class="hlt">frequency</span> of NRBCs, 89.4 +/- 92.6 cells appeared per 10 mL of maternal blood in the normal group, but NRBCs increased in patients with 18 trisomy, placenta previa, pre-eclampsia, intrauterine fetal death, and 21 trisomy. NRBC examination may play an assisting role not only in fetal diagnosis but also in fetomaternal diagnosis.</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://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/26300719','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26300719"><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="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ruffini, Nuria; D'Alessandro, Giandomenico; Mariani, Nicolò; Pollastrelli, Alberto; Cardinali, Lucia; Cerritelli, Francesco</p> <p>2015-01-01</p> <p>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. To investigate the influence of osteopathic manipulative treatment (OMT) on cardiac autonomic modulation in healthy subjects, compared with sham therapy and control group. 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. 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. 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). Findings suggested that OMT can influence ANS activity increasing parasympathetic function and decreasing sympathetic activity, compared to sham</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/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('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('https://www.osti.gov/scitech/biblio/6395949','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6395949"><span><span class="hlt">Separator</span> sub</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hayatdavoudi, A.</p> <p>1984-10-09</p> <p>Apparatus and methods are disclosed for drilling a well. A <span class="hlt">separator</span> sub is used to <span class="hlt">separate</span> a stream of drilling mud into a less dense first portion and more dense second portion. The less dense first portion of the stream of drilling mud is directed downward to a drill bit so that the drilling mud adjacent the drill bit has a density less than an initial density of the stream of drilling mud. The more dense second portion of the stream of drilling mud is ejected into a well annulus with an upward component of velocity and thereby reduces a hydrostatic drilling mud pressure adjacent the drill bit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6280001','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6280001"><span>Isotopic <span class="hlt">separation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chen, C.</p> <p>1981-03-10</p> <p>Method and apparatus for <span class="hlt">separating</span> isotopes in an isotopic mixture of atoms or molecules by increasing the mass differential among isotopic species. The mixture containing a particular isotope is selectively irradiated so as to selectively excite the isotope. This preferentially excited species is then reacted rapidly with an additional preselected radiation, an electron or another chemical species so as to form a product containing the specific isotope, but having a mass different than the original species initially containing the particular isotope. The product and the remaining balance of the mixture is then caused to flow through a device which <span class="hlt">separates</span> the product from the mixture based upon the increased mass differential.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014IzAOP..50..736Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014IzAOP..50..736Z"><span>Synchronization of human heart-rate indicators and geomagnetic field <span class="hlt">variations</span> in the <span class="hlt">frequency</span> range of 0.5-3.0 mHz</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zenchenko, T. A.; Medvedeva, A. A.; Khorseva, N. I.; Breus, T. K.</p> <p>2014-12-01</p> <p>Fifty-seven experiments have been conducted to monitor the minute indicators of heart rate at rest in 38 practically healthy individuals (9 men and 29 women) from 18 to 58 years old. The duration of each observation period is 60 to 200 min. We have measured the heart rate and the minute-averaged cardiac section durations reflecting the passage of electrical excitation over different parts of myocardium. A comparison of the dynamics of minute values of these physiological parameters with <span class="hlt">variations</span> of the X and Z components of the geomagnetic field has shown that two-thirds of experiments revealed the synchronization of oscillations in the heart rate and <span class="hlt">variations</span> in the components of the geomagnetic field. We have revealed both the matching of the observed periods of oscillations ranging between 4 and 30 min and an approximate synchronicity in the times of their appearance and disappearance.</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('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('https://www.ncbi.nlm.nih.gov/pubmed/25917883','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25917883"><span>Automated and visual measurements of estrous behavior and their sources of <span class="hlt">variation</span> in Holstein heifers. I: Walking activity and behavior <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>Silper, B F; Robles, I; Madureira, A M L; Burnett, T A; Reis, M M; de Passillé, A M; Rushen, J; Cerri, R L A</p> <p>2015-07-15</p> <p>Holstein heifers (n = 57) were monitored using accelerometers and video observations with the objective of better understanding the behavioral expression of estrus, the <span class="hlt">variation</span> within and between the heifers, and the possible sources of <span class="hlt">variation</span>. IceTags recorded walking activity from 7 to 13 months of age. Activity peaks (n = 282) were obtained from a rolling sum of steps within 24-hour periods and validated to be estrus by ovarian ultrasonography. Behavior around activity peak of one estrus for each of 12 heifers was described in detail from video recordings. Baseline behavior was monitored in a corresponding interval 1 week before. Estrus and baseline total steps and steps per hour, estrus relative increase in activity, duration, and interval between episodes were analyzed by descriptive statistics and Spearman rank correlations. Effects of category of baseline walking activity, estrus order (pubertal vs. second and greater episodes), season, hour of estrus onset, and number of heifers simultaneously in estrus were evaluated with proc MIXED. Behavioral changes from baseline to estrus were evaluated by a signed-rank test. Estrus total steps varied greatly (4743 ± 1740; range: 837-10,070), as well as the relative increase in activity (290 ± 160%; range: 30%-1190%). Duration of estrus was 14 ± 4 hours, ranging from 4 to 26 hours. The interval between episodes was the trait that varied the least. Pubertal estrus was shorter and had a smaller relative increase in activity than second and greater episodes (P < 0.05). The number of steps during estrus was greater for heifers of high baseline activity (P < 0.01). Estrus episodes occurring in the winter and starting between 4 PM and 3 AM had the greatest relative increase in activity (P < 0.05). The number of heifers simultaneously in estrus did not influence estrus expression (P > 0.05). The behaviors with greatest change from baseline to estrus were chin rest, sniff, back mount, crossover, accept chin rest, and</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.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('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.ncbi.nlm.nih.gov/pubmed/28757204','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28757204"><span>Low-<span class="hlt">Frequency</span> Synonymous Coding <span class="hlt">Variation</span> in CYP2R1 Has Large Effects on Vitamin D Levels and Risk of Multiple Sclerosis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Manousaki, Despoina; Dudding, Tom; Haworth, Simon; Hsu, Yi-Hsiang; Liu, Ching-Ti; Medina-Gómez, Carolina; Voortman, Trudy; van der Velde, Nathalie; Melhus, Håkan; Robinson-Cohen, Cassianne; Cousminer, Diana L; Nethander, Maria; Vandenput, Liesbeth; Noordam, Raymond; Forgetta, Vincenzo; Greenwood, Celia M T; Biggs, Mary L; Psaty, Bruce M; Rotter, Jerome I; Zemel, Babette S; Mitchell, Jonathan A; Taylor, Bruce; Lorentzon, Mattias; Karlsson, Magnus; Jaddoe, Vincent V W; Tiemeier, Henning; Campos-Obando, Natalia; Franco, Oscar H; Utterlinden, Andre G; Broer, Linda; van Schoor, Natasja M; Ham, Annelies C; Ikram, M Arfan; Karasik, David; de Mutsert, Renée; Rosendaal, Frits R; den Heijer, Martin; Wang, Thomas J; Lind, Lars; Orwoll, Eric S; Mook-Kanamori, Dennis O; Michaëlsson, Karl; Kestenbaum, Bryan; Ohlsson, Claes; Mellström, Dan; de Groot, Lisette C P G M; Grant, Struan F A; Kiel, Douglas P; Zillikens, M Carola; Rivadeneira, Fernando; Sawcer, Stephen; Timpson, Nicholas J; Richards, J Brent</p> <p>2017-08-03</p> <p>Vitamin D insufficiency is common, correctable, and influenced by genetic factors, and it has been associated with risk of several diseases. We sought to identify low-<span class="hlt">frequency</span> genetic variants that strongly increase the risk of vitamin D insufficiency and tested their effect on risk of multiple sclerosis, a disease influenced by low vitamin D concentrations. We used whole-genome sequencing data from 2,619 individuals through the UK10K program and deep-imputation data from 39,655 individuals genotyped genome-wide. Meta-analysis of the summary statistics from 19 cohorts identified in CYP2R1 the low-<span class="hlt">frequency</span> (minor allele <span class="hlt">frequency</span> = 2.5%) synonymous coding variant g.14900931G>A (p.Asp120Asp) (rs117913124[A]), which conferred a large effect on 25-hydroxyvitamin D (25OHD) levels (-0.43 SD of standardized natural log-transformed 25OHD per A allele; p value = 1.5 × 10(-88)). The effect on 25OHD was four times larger and independent of the effect of a previously described common variant near CYP2R1. By analyzing 8,711 individuals, we showed that heterozygote carriers of this low-<span class="hlt">frequency</span> variant have an increased risk of vitamin D insufficiency (odds ratio [OR] = 2.2, 95% confidence interval [CI] = 1.78-2.78, p = 1.26 × 10(-12)). Individuals carrying one copy of this variant also had increased odds of multiple sclerosis (OR = 1.4, 95% CI = 1.19-1.64, p = 2.63 × 10(-5)) in a sample of 5,927 case and 5,599 control subjects. In conclusion, we describe a low-<span class="hlt">frequency</span> CYP2R1 coding variant that exerts the largest effect upon 25OHD levels identified to date in the general European population and implicates vitamin D in the etiology of multiple sclerosis. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.</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://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.ncbi.nlm.nih.gov/pubmed/23372455','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23372455"><span>Component <span class="hlt">separations</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Heller, Lior; McNichols, Colton H; Ramirez, Oscar M</p> <p>2012-02-01</p> <p>Component <span class="hlt">separation</span> is a technique used to provide adequate coverage for midline abdominal wall defects such as a large ventral hernia. This surgical technique is based on subcutaneous lateral dissection, fasciotomy lateral to the rectus abdominis muscle, and dissection on the plane between external and internal oblique muscles with medial advancement of the block that includes the rectus muscle and its fascia. This release allows for medial advancement of the fascia and closure of up to 20-cm wide defects in the midline area. Since its original description, components <span class="hlt">separation</span> technique underwent multiple modifications with the ultimate goal to decrease the morbidity associated with the traditional procedure. The extensive subcutaneous lateral dissection had been associated with ischemia of the midline skin edges, wound dehiscence, infection, and seroma. Although the current trend is to proceed with minimally invasive component <span class="hlt">separation</span> and to reinforce the fascia with mesh, the basic principles of the techniques as described by Ramirez et al in 1990 have not changed over the years. Surgeons who deal with the management of abdominal wall defects are highly encouraged to include this technique in their collection of treatment options.</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> </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://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('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.ncbi.nlm.nih.gov/pubmed/27261878','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27261878"><span>Prefrontal activity during working memory is modulated by the interaction of <span class="hlt">variation</span> in CB1 and COX2 coding genes and correlates with <span class="hlt">frequency</span> of cannabis use.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Taurisano, Paolo; Antonucci, Linda A; Fazio, Leonardo; Rampino, Antonio; Romano, Raffaella; Porcelli, Annamaria; Masellis, Rita; Colizzi, Marco; Quarto, Tiziana; Torretta, Silvia; Di Giorgio, Annabella; Pergola, Giulio; Bertolino, Alessandro; Blasi, Giuseppe</p> <p>2016-08-01</p> <p>The CB1 cannabinoid receptor is targeted in the brain by endocannabinoids under physiological conditions as well as by delta9-tetrahydrocannabinol under cannabis use. Furthermore, its signaling appears to affect brain cognitive processing. Recent findings highlight a crucial role of cyclooxygenase-2 (COX-2) in the mechanism of intraneuronal CB1 signaling transduction, while others indicate that two single nucleotide polymorphisms (SNPs) (rs1406977 and rs20417) modulate expression of CB1 (CNR1) and COX-2 (PTGS2) coding genes, respectively. Here, our aim was to use fMRI to investigate in healthy humans whether these SNPs interact in modulating prefrontal activity during working memory processing and if this modulation is linked with cannabis use. We recruited 242 healthy subjects genotyped for CNR1 rs1406977 and PTGS2 rs20417 that performed the N-back working memory task during fMRI and were interviewed using the Cannabis Experience Questionnaire (CEQ). We found that the interaction between CNR1 rs1406977 and PTGS2 rs20417 is associated with dorsolateral prefrontal cortex (DLPFC) activity such that specific genotype configurations (CNR1 C carriers/PTGS2 C carriers and CNR1 TT/PTGS2 GG) predict lower cortical response versus others in spite of similar behavioral accuracy. Furthermore, DLPFC activity in the cluster associated with the CNR1 by PTGS2 interaction was negatively correlated with behavioral efficiency and positively correlated with <span class="hlt">frequency</span> of cannabis use in cannabis users. These results suggest that a genetically modulated balancing of signaling within the CB1-COX-2 pathway may reflect on more or less efficient patterns of prefrontal activity during working memory. <span class="hlt">Frequency</span> of cannabis use may be a factor for further modulation of CNR1/PTGS2-mediated cortical processing associated with this cognitive process. Copyright © 2016 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5052851','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5052851"><span><span class="hlt">Variation</span> of availability and <span class="hlt">frequency</span> of emergency physician-performed ultrasonography between adult and pediatric patients in the academic emergency department in Korea</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ahn, Chiwon; Kim, Changsun; Kang, Bo Seung; Choi, Hyuk Joong; Cho, Jun Hwi</p> <p>2015-01-01</p> <p>Objective This study investigates the availability and <span class="hlt">frequency</span> of emergency physician-performed ultrasonography (USG) in the emergency department (ED) and the status of USG training programs in emergency medicine residencies in academic EDs in Korea. Methods In spring 2014, a link to a 16-question, multiple-choice, and rating scale web-based survey was e-mailed to all 97 academic ED residency training directors in Korea. Results The response rate was 83.5% (81/97). All respondents had their own USG machines in the ED. In total, 82.7% of respondents reported that emergency physician-performed adult USGs were usually conducted daily, whereas only 23.6% performed pediatric USGs daily. Moreover, 55.5% performed pediatric USG fewer than once a week. 74.1% of respondents had education programs for adult USG in residency training, but only 21.0% had programs for pediatric USG. There was a high association between the presence of education programs and the use of USG in both groups. The faculty members who most commonly participated in teaching ED residents how to perform USG were emergency physicians (67.9%). Only 17.3% of respondents reported that they always supported a quality assurance process. The training directors generally agreed with the advantages in emergency physician-performed USGs. Conclusion The availability of ultrasound machines was high both for adult and pediatric EDs. Nevertheless, the <span class="hlt">frequency</span> of Emergency physician-performed USG for pediatric patients was low, which was related to the lack of the training programs for treating pediatric patients. PMID:27752568</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27752568','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27752568"><span><span class="hlt">Variation</span> of availability and <span class="hlt">frequency</span> of emergency physician-performed ultrasonography between adult and pediatric patients in the academic emergency department in Korea.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ahn, Chiwon; Kim, Changsun; Kang, Bo Seung; Choi, Hyuk Joong; Cho, Jun Hwi</p> <p>2015-03-01</p> <p>This study investigates the availability and <span class="hlt">frequency</span> of emergency physician-performed ultrasonography (USG) in the emergency department (ED) and the status of USG training programs in emergency medicine residencies in academic EDs in Korea. In spring 2014, a link to a 16-question, multiple-choice, and rating scale web-based survey was e-mailed to all 97 academic ED residency training directors in Korea. The response rate was 83.5% (81/97). All respondents had their own USG machines in the ED. In total, 82.7% of respondents reported that emergency physician-performed adult USGs were usually conducted daily, whereas only 23.6% performed pediatric USGs daily. Moreover, 55.5% performed pediatric USG fewer than once a week. 74.1% of respondents had education programs for adult USG in residency training, but only 21.0% had programs for pediatric USG. There was a high association between the presence of education programs and the use of USG in both groups. The faculty members who most commonly participated in teaching ED residents how to perform USG were emergency physicians (67.9%). Only 17.3% of respondents reported that they always supported a quality assurance process. The training directors generally agreed with the advantages in emergency physician-performed USGs. The availability of ultrasound machines was high both for adult and pediatric EDs. Nevertheless, the <span class="hlt">frequency</span> of Emergency physician-performed USG for pediatric patients was low, which was related to the lack of the training programs for treating pediatric patients.</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://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('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> <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/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('https://www.ncbi.nlm.nih.gov/pubmed/26765993','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26765993"><span><span class="hlt">Variations</span> in voice level and fundamental <span class="hlt">frequency</span> with changing background noise level and talker-to-listener distance while wearing hearing protectors: A pilot study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bouserhal, Rachel E; Macdonald, Ewen N; Falk, Tiago H; Voix, Jérémie</p> <p>2016-01-01</p> <p>Speech production in noise with varying talker-to-listener distance has been well studied for the open ear condition. However, occluding the ear canal can affect the auditory feedback and cause deviations from the models presented for the open-ear condition. Communication is a main concern for people wearing hearing protection devices (HPD). Although practical, radio communication is cumbersome, as it does not distinguish designated receivers. A smarter radio communication protocol must be developed to alleviate this problem. Thus, it is necessary to model speech production in noise while wearing HPDs. Such a model opens the door to radio communication systems that distinguish receivers and offer more efficient communication between persons wearing HPDs. This paper presents the results of a pilot study aimed to investigate the effects of occluding the ear on changes in voice level and fundamental <span class="hlt">frequency</span> in noise and with varying talker-to-listener distance. Twelve participants with a mean age of 28 participated in this study. Compared to existing data, results show a trend similar to the open ear condition with the exception of the occluded quiet condition. This implies that a model can be developed to better understand speech production for the occluded ear.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26474968','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26474968"><span>The existence of Th22, pure Th17 and Th1 cells in CIN and Cervical Cancer along with their <span class="hlt">frequency</span> <span class="hlt">variation</span> in different stages of cervical cancer.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Wenjing; Tian, Xinli; Mumtahana, Fidia; Jiao, Jun; Zhang, Teng; Croce, Kimiko Della; Ma, Daoxin; Kong, Beihua; Cui, Baoxia</p> <p>2015-10-16</p> <p>Recently, it is found that T-helper (Th) 22 cells are involved in different types of autoimmune and tumor diseases. But, till now, no study has been carried out to understand the involvement of these cells in cervical cancer (CC). Flow cytometry was used to determine the expression of interferon gamma (IFN-γ), Interleukin-22 (IL-22), IL-17 in the peripheral blood of healthy controls (HC), CIN and cervical cancer patients. From peripheral blood mononuclear cells (PBMCs), mRNA expression levels of Aryl hydrocarbon receptor (AHR), RAR-related orphan receptor C (RORC), TNF-α and IL-6 were respectively determined. Using the method of ELISA, plasma concentrations of IL-22, IL-17 and TNF-α were examined. Th22 and Th17 cells were elevated in CC and CIN patients. Th1 cells and the plasma concentrations of IL-22 in CC patients were significantly increased compared with HC. In CC patients, an increased prevalence of Th22 cells was associated with lymph node metastases. There was a positive correlation between Th22 and Th17 cells, but an approximately negative correlation between Th22 and Th1 cells in CC patients. The mRNA expression of RORC, TNF-α and IL-6 was significantly high in CC patients. Our results indicate that there is a higher circulatory <span class="hlt">frequency</span> of Th22, Th17 and Th1 cells in CC which may conjointly participate in the pathogenesis and growth of CC.</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/2013JGRD..11811647M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRD..11811647M"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matsui, H.; Koike, M.; Takegawa, N.; Kondo, Y.; Takami, A.; Takamura, T.; Yoon, S.; Kim, S.-W.; Lim, H.-C.; Fast, J. D.</p> <p>2013-10-01</p> <p>recently developed new particle formation (NPF)-explicit version of the Weather Research and Forecasting Chemistry (WRF-chem) model can explicitly calculate the growth and sink of nucleated clusters with 20 aerosol size bins from 1 nm to 10 µm in diameter. In this study, the model was used to investigate spatial and temporal <span class="hlt">variations</span> in NPF event <span class="hlt">frequency</span> and the concentrations of aerosols (condensation nuclei, CN) and cloud condensation nuclei (CCN) within the boundary layer in East Asia in spring 2009. We found a distinct north-south contrast in the NPF <span class="hlt">frequency</span> and mechanism in East Asia. NPF occurred mainly during limited periods over certain regions between 30° and 45°N (northeast China, Korea, and Japan, including regions around the active volcanoes Miyakejima and Sakurajima). In these latitudes, NPF was suppressed by high concentrations of preexisting particles under stagnant air conditions associated with high-pressure systems, although nucleation occurred more extensively during most of the simulation period. In contrast, south of 30°N, nucleation and NPF were both infrequent because of low SO2 emissions and H2SO4 concentrations. The period-averaged NPF <span class="hlt">frequency</span> at 30°-45°N was three times that at 20°-30°N. This north-south contrast in NPF <span class="hlt">frequency</span> was validated by surface measurements in outflow regions of East Asia. The simulated period- and domain-averaged contribution of secondary particles was estimated to be 44% for CN (>10 nm) and 26% for CCN at a supersaturation of 1.0%, though the contribution was highly sensitive to the amount and size distribution of primary aerosol emissions and the rate coefficient of the nucleation parameterization.</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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4209190','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4209190"><span>Increased <span class="hlt">Frequency</span> of De Novo Copy Number <span class="hlt">Variations</span> in Congenital Heart Disease by Integrative Analysis of SNP Array and Exome Sequence Data</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rodriguez-Murillo, Laura; Fromer, Menachem; Mazaika, Erica; Vardarajan, Badri; Italia, Michael; Leipzig, Jeremy; DePalma, Steven R.; Golhar, Ryan; Sanders, Stephan J.; Yamrom, Boris; Ronemus, Michael; Iossifov, Ivan; Willsey, A. Jeremy; State, Matthew W.; Kaltman, Jonathan R.; White, Peter S.; Shen, Yufeng; Warburton, Dorothy; Brueckner, Martina; Seidman, Christine; Goldmuntz, Elizabeth; Gelb, Bruce D.; Lifton, Richard; Seidman, Jonathan; Hakonarson, Hakon; Chung, Wendy K.</p> <p>2014-01-01</p> <p>Rationale Congenital heart disease (CHD) is among the most common birth defects. Most cases are of unknown etiology. Objective To determine the contribution of de novo copy number variants (CNVs) in the etiology of sporadic CHD. Methods and Results We studied 538 CHD trios using genome-wide dense single nucleotide polymorphism (SNP) arrays and/or whole exome sequencing (WES). Results were experimentally validated using digital droplet PCR. We compared validated CNVs in CHD cases to CNVs in 1,301 healthy control trios. The two complementary high-resolution technologies identified 63 validated de novo CNVs in 51 CHD cases. A significant increase in CNV burden was observed when comparing CHD trios with healthy trios, using either SNP array (p=7x10−5, Odds Ratio (OR)=4.6) or WES data (p=6x10−4, OR=3.5) and remained after removing 16% of de novo CNV loci previously reported as pathogenic (p=0.02, OR=2.7). We observed recurrent de novo CNVs on 15q11.2 encompassing CYFIP1, NIPA1, and NIPA2 and single de novo CNVs encompassing DUSP1, JUN, JUP, MED15, MED9, PTPRE SREBF1, TOP2A, and ZEB2, genes that interact with established CHD proteins NKX2-5 and GATA4. Integrating de novo variants in WES and CNV data suggests that ETS1 is the pathogenic gene altered by 11q24.2-q25 deletions in Jacobsen syndrome and that CTBP2 is the pathogenic gene in 10q sub-telomeric deletions. Conclusions We demonstrate a significantly increased <span class="hlt">frequency</span> of rare de novo CNVs in CHD patients compared with healthy controls and suggest several novel genetic loci for CHD. PMID:25205790</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Frequency&id=EJ1056039','ERIC'); return false;" href="https://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://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> </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://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('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('https://www.ncbi.nlm.nih.gov/pubmed/732496','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/732496"><span>Laryngotracheal <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>LeJeune, F E</p> <p>1978-12-01</p> <p>The popularity of the motorcycle, specifically trail bike riding, in the past several years has produced an increasing incidence of severe "clothesline" injuries to the larynx and trachea. Even at moderately high speed the impact of a horizontal cable with the neck of the rider causes a sudden hyperextension of the neck, and an avulsion of the larynx from the trachea, <span class="hlt">separating</span> at the relatively rigid fibrous connective tissue between the cricoid cartilage and the first tracheal ring. Interruption of the strap muscles, the recurrent laryngeal nerves, laceration of the esophagus, and compression fracture of the cervical vertebral bodies can occur. The unseated rider requires immediate assistance, airway obstruction being his greatest problem. In the early minutes after the accident he must be transported to an emergency facility where tracheostomy and resuscitation can be provided. Mediastinal infection, tracheoesophageal fistula, subglottic stenosis, and intermittent depression many follow the initial repair. Rehabilitative measures include permanent tracheostomy, the use of neuromuscular pedicle graft, hyoid bone graft, intracordal injection of teflon paste, and carbon dioxide laser excision of webs and cicatricial tissue.</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://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('https://www.ncbi.nlm.nih.gov/pubmed/16086836','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16086836"><span>High <span class="hlt">frequency</span> of the IVS2-2A>G DNA sequence <span class="hlt">variation</span> in SLC26A5, encoding the cochlear motor protein prestin, precludes its involvement in hereditary hearing loss.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tang, Hsiao-Yuan; Xia, Anping; Oghalai, John S; Pereira, Fred A; Alford, Raye L</p> <p>2005-08-08</p> <p>Cochlear outer hair cells change their length in response to <span class="hlt">variations</span> in membrane potential. This capability, called electromotility, is believed to enable the sensitivity and <span class="hlt">frequency</span> selectivity of the mammalian cochlea. Prestin is a transmembrane protein required for electromotility. Homozygous prestin knockout mice are profoundly hearing impaired. In humans, a single nucleotide change in SLC26A5, encoding prestin, has been reported in association with hearing loss. This DNA sequence <span class="hlt">variation</span>, IVS2-2A>G, occurs in the exon 3 splice acceptor site and is expected to abolish splicing of exon 3. To further explore the relationship between hearing loss and the IVS2-2A>G transition, and assess allele <span class="hlt">frequency</span>, genomic DNA from hearing impaired and control subjects was analyzed by DNA sequencing. SLC26A5 genomic DNA sequences from human, chimp, rat, mouse, zebrafish and fruit fly were aligned and compared for evolutionary conservation of the exon 3 splice acceptor site. Alternative splice acceptor sites within intron 2 of human SLC26A5 were sought using a splice site prediction program from the Berkeley Drosophila Genome Project. The IVS2-2A>G variant was found in a heterozygous state in 4 of 74 hearing impaired subjects of Hispanic, Caucasian or uncertain ethnicity and 4 of 150 Hispanic or Caucasian controls (p = 0.45). The IVS2-2A>G variant was not found in 106 subjects of Asian or African American descent. No homozygous subjects were identified (n = 330). Sequence alignment of SLC26A5 orthologs demonstrated that the A nucleotide at position IVS2-2 is invariant among several eukaryotic species. Sequence analysis also revealed five potential alternative splice acceptor sites in intron 2 of human SLC26A5. These data suggest that the IVS2-2A>G variant may not occur more frequently in hearing impaired subjects than in controls. The identification of five potential alternative splice acceptor sites in intron 2 of human SLC26A5 suggests a potential mechanism by which</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://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> <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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3511662','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3511662"><span><span class="hlt">Frequency</span> Specific Ultrasound Attenuation Is Sensitive to Trabecular Bone Structure</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lin, Wei; Serra-Hsu, Frederick; Chen, Jiqi; Qin, Yi-Xian</p> <p>2012-01-01</p> <p>This study investigated the efficacy of <span class="hlt">frequency</span> modulated ultrasound attenuation in the assessment of the trabecular structural properties. Four <span class="hlt">frequency</span> modulated signals were created to represent four <span class="hlt">frequency</span> bands centered at 500 kHz, 900 kHz, 1.3 MHz and 1.7 MHz with the bandwidth of 400 kHz. Five one-centimeter trabecular cubes were harvested from fresh bovine distal femur. The cubes underwent four steps of demineralization process to expand the sample size to twenty five with the greater <span class="hlt">variations</span> of the structural properties for the better correlation study. Pearson correlation study was performed between the ultrasound attenuation in four <span class="hlt">frequency</span> bands and the trabecular structural properties. The results showed that correlations of <span class="hlt">frequency</span> modulated ultrasound attenuation to the trabecular structural properties are dependent on <span class="hlt">frequency</span> bands. The attenuation in proximal-distal orientation had the highest correlation to BV/TV (R2=0.73, p<0.001) and trabecular thickness (R2=0.50, p<0.001) at the <span class="hlt">frequency</span> band centered at 1.7 MHz. It was equivalent in the four <span class="hlt">frequency</span> bands in correlation to the trabecular number (average R2=0.80, p<0.001) and to the trabecular <span class="hlt">separation</span> (average R2 =0.83, p<0.001). The attenuation in anterio-posterial orientation had the highest correlation to BV/TV (R2=0.80, p<0.001) and trabecular thickness (R2=0.71, p<0.001) at the <span class="hlt">frequency</span> band centered at 1.3 MHz. The attenuation in the first <span class="hlt">frequency</span> band was the most sensitive to the trabecular number (R2=0.71, p<0.001) and trabecular <span class="hlt">separation</span> (R2=0.80, p<0.001). No significant correlation was observed for the attenuation in medial-lateral orientation across the four <span class="hlt">frequency</span> bands. PMID:22975035</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/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('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('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.osti.gov/scitech/biblio/20880192','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20880192"><span><span class="hlt">Frequency</span> coupling in dual <span class="hlt">frequency</span> capacitively coupled radio-<span class="hlt">frequency</span> plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gans, T.; Schulze, J.; O'Connell, D.; Czarnetzki, U.; Faulkner, R.; Ellingboe, A. R.; Turner, M. M.</p> <p>2006-12-25</p> <p>An industrial, confined, dual <span class="hlt">frequency</span>, capacitively coupled, radio-<span class="hlt">frequency</span> plasma etch reactor (Exelan registered , Lam Research) has been modified for spatially resolved optical measurements. Space and phase resolved optical emission spectroscopy yields insight into the dynamics of the discharge. A strong coupling of the two <span class="hlt">frequencies</span> is observed in the emission profiles. Consequently, the ionization dynamics, probed through excitation, is determined by both <span class="hlt">frequencies</span>. The control of plasma density by the high <span class="hlt">frequency</span> is, therefore, also influenced by the low <span class="hlt">frequency</span>. Hence, <span class="hlt">separate</span> control of plasma density and ion energy is rather complex.</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>