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Sample records for medium frequency repeats

  1. (Efficient identification and analysis of low and medium frequency repeats)

    SciTech Connect

    Jurka, J.

    1991-08-28

    The effective starting date of this grant was May 15. In the first three months of this project we focused primarily on organizational and technical aspects of our research which included: organization of the database of repeats in primates; preparation of software for rapid and sensitive search of novel repetitive elements in GenBank; purchase and installation of the Sun workstation; and research on the mammal-specific MAR1 family of repetitive elements (to be communicated in October).

  2. [Efficient identification and analysis of low and medium frequency repeats]. Progress report

    SciTech Connect

    Jurka, J.

    1991-08-28

    The effective starting date of this grant was May 15. In the first three months of this project we focused primarily on organizational and technical aspects of our research which included: organization of the database of repeats in primates; preparation of software for rapid and sensitive search of novel repetitive elements in GenBank; purchase and installation of the Sun workstation; and research on the mammal-specific MAR1 family of repetitive elements (to be communicated in October).

  3. Comparison of Medium Frequency Burst Generation Theories

    NASA Astrophysics Data System (ADS)

    Bunch, N. L.; Labelle, J. W.; Weatherwax, A. T.; Yoon, P. H.

    2009-12-01

    Auroral Medium Frequency (MF) burst is a naturally occurring spontaneous impulsive radio emission observed at ground level between 800 and 4500 kHz. MF burst has been shown to be associated with auroral substorm onset, commonly observed coincidentally with auroral roar and hiss, with typical durations of a few minutes, amplitudes of ~10-14 V^2 /m^2 Hz, and measured to be left hand polarized. Despite several suggested theories, the exact generation mechanism for MF burst still remains a mystery. Recent experimental findings combined with a discussion of normal wave modes available in the auroral ionosphere allow us to constrain potential modes of generation. Normal modes available in the auroral ionosphere (Omega_ce = ~800-1600 kHz, omega_pe = ~100-6000 kHz between 100 and 1000 km altitude) include R-X, L-O, Z (L-X), Langmuir-upper hybrid, electron cyclotron, electron acoustic, and electron cyclotron sound. Each mode is considered in light of experimental evidence, including accessibility to the L-O mode for propagation to ground with left hand polarization, and requirements for excitation by an auroral electron beam (100-10s of keV). A linear mode conversion process is also preferred over non-linear due to their inefficiency. Specific scenarios include: mode conversion of Langmuir waves at a range of altitudes on either the top or bottom side F-region, short wavelength (thermal branch) Langmuir waves, electron acoustic waves, electron cyclotron sound waves, direct generation of the L mode, and refraction and conversion of Z / upper hybrid waves - similar to that of auroral roar.

  4. Repeated injection of contrast medium inducing dysfunction of the blood-brain barrier: case report.

    PubMed

    Iwata, Tomonori; Mori, Takahisa; Tajiri, Hiroyuki; Miyazaki, Yuichi; Nakazaki, Masahito

    2013-01-01

    An early 60s-year-old man suffered reversible dysfunction of the blood-brain barrier (BBB) induced by repeated injection of contrast medium during coil embolization of intracranial unruptured aneurysm. He presented with convulsion during coil embolization, and neurological symptoms of aphasia and right hemiparesis continued for 5 days, and then improved completely. All transient radiological abnormalities were limited to the territory of the left internal carotid artery, where contrast medium was injected repeatedly. Repeated computed tomography, magnetic resonance imaging, single-photon emission computed tomography, and cerebrospinal fluid test findings indicated that temporary dysfunction of the BBB might have occurred. Dysfunction of the BBB in the anterior circulation induced by contrast medium is rare. Tolerance to toxicity of contrast medium may depend on the individual patient, and repeated injection of contrast medium may cause dysfunction of the BBB, leading to toxic dysfunction directly in the brain.

  5. Medium Frequency Pseudo Noise Geological Radar

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James R. (Inventor); Byerly, Kent A. (Inventor); Amini, B. Jon (Inventor)

    2003-01-01

    System and methods are disclosed for transmitting and receiving electromagnetic pulses through a geological formation. A preferably programmable transmitter having an all-digital portion in a preferred embodiment may be operated at frequencies below 1 MHz without loss of target resolution by transmitting and over sampling received long PN codes. A gated and stored portion of the received signal may be correlated with the PN code to determine distances of interfaces within the geological formation, such as the distance of a water interfaces from a wellbore. The received signal is oversampled preferably at rates such as five to fifty times as high as a carrier frequency. In one method of the invention, an oil well with multiple production zones may be kept in production by detecting an approaching water front in one of the production zones and shutting down that particular production zone thereby permitting the remaining production zones to continue operating.

  6. Frequency of Repeated Courses Its Relation to Persistence and Performance in Lebanon's Higher Education

    ERIC Educational Resources Information Center

    Nasser, Ramzi; Nauffal, Diane

    2012-01-01

    This study assesses the relationship between the frequency of repeating courses and students' performance in college. The study uses cohort data from academic years 2000/2001, 2001/2002, 2002/2003 and 2003/2004. We compared those who had repeated one, two and three courses on GPA and whether a relation exists of those who graduated/did not…

  7. In situ observations of medium frequency auroral radio emissions

    NASA Astrophysics Data System (ADS)

    Broughton, M.; Labelle, J. W.; Pfaff, R. F.; Parrot, M.; Yan, X.; Burchill, J. K.

    2013-12-01

    The auroral ionosphere is a region rich with plasma waves that can be studied both in space and on the ground. These waves may mediate energy exchange between particle populations and provide information about the local plasma properties and boundaries. Auroral medium frequency (MF) burst is an impulsive radio emission observed at ground-level from 1.3-4.5 MHz that is associated with local substorm onset. There have been two recent reports of impulsive, broadband, MF waves at high latitudes. Burchill and Pfaff [2005] reported observations from the FAST satellite of impulsive, broadband, MF and low frequency (LF) radio waves. Using data from the DEMETER satellite, Parrot et al. [2009] surveyed MF waves caused by lightning. This study did show a high-latitude population of MF waves. We investigate whether the waves observed by these two satellites are related to auroral MF burst. Using FAST satellite burst mode electric field data from high-latitude (> 60 degrees magnetic), low-altitude (< 1000 km) intervals of moderate to large geomagnetic activity (Kp > 3) from 1996-2002, we have found forty-four examples of impulsive MF waves, all of which are associated with impulsive LF waves. Although MF burst and the waves observed by FAST have similar spectral signatures, they have different magnetic local time dependencies, which suggests that they may be unrelated. A study of MF waves observed at high latitude by DEMETER is ongoing. In situ observations of MF burst could provide crucial information about this heretofore unexplained natural radio emission.

  8. Simulation of polarizer based on chiral medium for terahertz frequency range

    NASA Astrophysics Data System (ADS)

    Korolenko, S. Yu; Grebenchukov, A. N.; Masyukov, M. S.; Vozianova, A. V.; Khodzitsky, M. K.

    2016-08-01

    The work is devoted to development of the polarizer for terahertz frequency range. Chiral medium was simulated using the software package CST Microwave Studio by the method of Finite-Differences in Frequency Domain. The influence of geometry of chiral unit cell on the polarization of incident plane wave was investigated.

  9. FIRST VERY LOW FREQUENCY DETECTION OF SHORT REPEATED BURSTS FROM MAGNETAR SGR J1550-5418

    SciTech Connect

    Tanaka, Y. T.; Takahashi, T.; Raulin, Jean-Pierre; Bertoni, Fernando C. P.; Fagundes, P. R.; Chau, J.; Schuch, N. J.; Hayakawa, M.; Hobara, Y.; Terasawa, T.

    2010-09-20

    We report on the first detection of ionospheric disturbances caused by short repeated gamma-ray bursts from the magnetar SGR J1550-5418. Very low frequency (VLF) radio wave data obtained in South America clearly show sudden amplitude and phase changes at the corresponding times of eight soft gamma-ray repeater bursts. Maximum amplitude and phase changes of the VLF signals appear to be correlated with the gamma-ray fluence. On the other hand, VLF recovery timescales do not show any significant correlation with the fluence, possibly suggesting that the bursts' spectra are not similar to each other. In summary, Earth's ionosphere can be used as a very large gamma-ray detector and the VLF observations provide us with a new method to monitor high-energy astrophysical phenomena without interruption such as Earth occultation.

  10. Thermal Behavior of a Medium-Frequency Ferrite-Core Power Transformer

    NASA Astrophysics Data System (ADS)

    Balci, Selami; Sefa, Ibrahim; Altin, Necmi

    2016-08-01

    In this study, design and thermal analysis of a medium-frequency transformer with ferrite N87 core have been carried out using finite-element analysis software. A thermal model of the medium-frequency transformer is generated and analyzed with different cooling methods. In addition, it is proposed to attach additional heat sinks at the top and bottom of the transformer core. Effects of these additional heat sinks on cooling performance and sizing of the transformer are investigated. Furthermore, the cooling capacity of the proposed material is investigated, depending on the air flow velocity for the forced-air cooling method. Thus, more realistic behavior of the ferrite N87 material is obtained for a medium-frequency transformer with 35 kVA rated power and 10 kHz operating frequency. Moreover, electromagnetic and thermal analyses are carried out through linked simulations. The heat distribution in the core including saturation effect is also investigated in detail.

  11. Repeatability and relative validity of a quantitative food-frequency questionnaire among French adults

    PubMed Central

    Barrat, Emmanuel; Aubineau, Nicolas; Maillot, Matthieu; Derbord, Élodie; Barthes, Pauline; Lescuyer, Jean-François; Boisseau, Nathalie; Peltier, Sébastien L.

    2012-01-01

    Background A 50-item self-administered food frequency questionnaire (FFQ) was developed for French adults, to assess the intake of energy, 10 macronutrients, 11 vitamins, and 11 minerals, and to be used in the context of a medical consultation. Objective To assess the repeatability and relative validity of this FFQ compared to a 7-day diet record (7-DR). Design A total of 54 and 100 French adults were included in the repeatability and validation studies, respectively. Repeatability was assessed using two FFQs, the second carried out 3 weeks after the first. In the validation study, subjects first completed the FFQ, then the 7-DR the following week. Energy and nutrient intakes were compared using Pearson correlation. The degree of misclassification by the FFQ, compared to the 7-DR, was calculated by a contingency table of quintiles. Bland–Altman plots assessed the correlation between FFQ and 7-DR across the intake range. Results Repeatability for intake, explored by Pearson correlation, was 0.62–0.90 (median: 0.81). Relative validity, as determined by Pearson correlation for the nutrient intake derived from the FFQ and 7-DR, was 0.36–0.80 (0.64). The FFQ tended to report higher fiber and micronutrient intake than 7-DR. Misclassification into opposite quintiles ranged 0–6% (1%), whereas classification into same or adjacent quintiles ranged 59–83% (74%). Bland–Altman plots showed good agreement for most nutrients across the range of intake. Conclusion This new FFQ showed a high repeatability and good relative validity, and thanks to its short length, should be a useful tool for rapidly evaluating the nutrient intake of French adults. PMID:23118710

  12. Unraveling the Intricacies of Cascadia Slow-Slip Rupture Using Repeating Low-Frequency Earthquakes

    NASA Astrophysics Data System (ADS)

    Creager, K. C.; Sweet, J. R.; Chestler, S.; Houston, H.; Vidale, J. E.

    2013-12-01

    Using data from the 2-year Array of Arrays and the 6-year CAFE seismic experiments on the Olympic Peninsula, Washington, we have identified and located nine groups (families) of repeating Low-Frequency Earthquakes (LFEs). Each family locates within a few km of the plate interface as estimated by active-source wide-angle reflections (Preston et al., Science, 2003) and repeats 100s to 10,000 times in intriguing temporal patterns. At the down-dip end they light up every 1-2 weeks, each with 10s to 100s of LFE repeats, during typical time scales of about one hour. Double-difference locations indicate the LFEs are constrained to a linear patch 2 km long, on the plate interface elongated in the direction of relative plate motion. In contrast, the up-dip-most LFE family lights up primarily during the big 14-month Episodic Tremor and Slip (ETS) events. It repeatedly exhibits a pattern of being quiet for 14 months, then lighting up with hundreds of repeats during a few hour period, which we interpret as the main ETS rupture front passing the location of the LFE family. This is followed by a five-day period of quiescence punctuated by about a dozen short-duration episodes of frenzied LFE activity. Monitoring LFE families within 20 km of each other, we find their bursts of activity correlate roughly with each other, but with time lags of 10s of minutes to hours. We interpret this activity as the passage of streaks and Rapid Tremor Reversals that occur during the 5 days after the main rupture front passes. After this time, either the stress is relieved, or the fault has healed and the LFE family is quiet for another 14 months. The magnitudes of the down-dip LFEs, based on S-wave amplitudes, range from -1 to 1. In the limited magnitude range over which our LFE catalog is complete (0.6 magnitude units) they appear to follow a Gutenberg-Richter distribution with a very large b-value of 4. There is a systematic pattern of short-duration LFE activity happening often (every 1

  13. Improvement in medium long-term frequency stability of the integrating sphere cold atom clock

    NASA Astrophysics Data System (ADS)

    Liu, Peng; Cheng, Huadong; Meng, Yanling; Wan, Jinyin; Xiao, Ling; Wang, Xiumei; Wang, Yaning; Liu, Liang

    2016-07-01

    The medium-long term frequency stability of the integrating sphere cold atom clock was improved.During the clock operation, Rb atoms were cooled and manipulated using cooling light diffusely reflected by the inner surface of a microwave cavity in the clock. This light heated the cavity and caused a frequency drift from the resonant frequency of the cavity. Power fluctuations of the cooling light led to atomic density variations in the cavity's central area, which increased the clock frequency instability through a cavity pulling effect. We overcame these limitations with appropriate solutions. A frequency stability of 3.5E-15 was achieved when the integrating time ? increased to 2E4 s.

  14. Variation in high-frequency wave radiation from small repeating earthquakes as revealed by cross-spectral analysis

    NASA Astrophysics Data System (ADS)

    Hatakeyama, Norishige; Uchida, Naoki; Matsuzawa, Toru; Okada, Tomomi; Nakajima, Junichi; Matsushima, Takeshi; Kono, Toshio; Hirahara, Satoshi; Nakayama, Takashi

    2016-11-01

    We examined the variation in the high-frequency 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 frequency band higher than the corner frequencies are different from those in a lower frequency band for particular event pairs. The phases and coherences show that there are coherent high-frequency waves for almost all the repeaters regardless of the high-frequency delays. These results indicate that high-frequency 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-frequency band interevent delays relative to the low-frequency 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-frequency wave differences were caused by stress perturbations due to the nearby earthquakes. In summary, our observations suggest that high-frequency waves from the repeating sequence are radiated not from everywhere but from a long-duration subpatch within the seismic slip area. The

  15. Time History of Repeating Low-Frequency Earthquakes Spanning 5 Years

    NASA Astrophysics Data System (ADS)

    Sweet, J. R.; Creager, K. C.

    2011-12-01

    Low-frequency earthquakes (LFEs) are a recently identified class of earthquakes that occur coincidentally with tectonic tremor in time and space. LFEs comprise much of the tectonic tremor in Japan, and LFE locations have been used to pin down the location of tremor bursts within subduction zones around the world (Brown et al., 2009, GRL), as well as on deep segments of the San Andreas Fault (Shelly et al., 2009, GRL). While prior LFE studies have allowed us to see where and when various fault patches are radiating seismic energy with unprecedented detail, the time history of repeating LFEs has received less attention. Using well-recorded LFEs as templates, we employ a cross-correlation filter to find matching events. We have identified several locations in the northern Cascadia subduction zone which produce LFEs that repeated several hundred times during the past five years. The LFEs are active during multiple Episodic Tremor and Slip (ETS) events. In each case, the matching events first appear rather suddenly and at a feverish pace. Following this initial burst of several hours, the events exhibit a much more discrete pattern of recurrence that starts out as frequent pops that become less and less frequent over a period of several days. We suggest that the initial burst is associated with the passage of a slip front on the fault surface at the location of the template event. Later pops may be attributed to resurgent slow slip that briefly generates seismic energy during the days following the passage of the initial slip front. One LFE template was also active during an inter-ETS event. Its time history was similar to the initial bursts during the ETS events, but it was not followed by the later pops-perhaps due to the absence of resurgent slow slip during the small inter-ETS event. We have previously identified several additional LFE templates that occurred during smaller inter-ETS episodes farther downdip of the main ETS zone. Using these additional templates, we

  16. A Experimental Determination of the Resonant Frequency of Atoms Moving in a Medium

    NASA Astrophysics Data System (ADS)

    Beary, Daniel Andrew

    The theory of the Doppler-Recoil effect is described. In contrast to previous theories, the theory proposed by Haugan and Kowalski suggests that the frequency of the electromagnetic wave that excites a transition in an atom is a function of the velocity of that atom and the index of refraction of the medium. Following the path of Haugan and Kowalski, the Doppler Recoil equation is derived under the conditions of a rarefied gas acting as a continuous medium. Next, the theory of saturation spectroscopy is revised. This method of spectroscopy uses a pump and probe beam traveling collinearly in opposite directions. Beams of equal frequency in the lab frame interact with the zero axial velocity population within the gas when the beams are on resonance. For pump and probe beams of different frequencies, the atoms that they interact with will have an axial velocity component such that the Doppler shift leads to resonance with both beams. The purpose of this work is to verify the Doppler -Recoil formula proposed by Haugan and Kowalski. In the experiment performed, the resonant frequency of the stationary and moving velocity groups is determined using saturation spectroscopy. The theory predicts an average frequency shift of 307 Hz/^circC. The data show a shift of 94 kHz/^circ C. Because of the unexpected result, possible sources of errors such as pressure broadening, power broadening, and potential for systematic errors were examined. No explanation was found for these shifts.

  17. Mesospheric wind measurements using a medium-frequency imaging Doppler interferometer

    NASA Technical Reports Server (NTRS)

    Adams, G. W.; scatterers.

    1986-01-01

    Wind results from a medium-frequency radar operated as an imaging Doppler interferometer are presented. Ten independent antennas, together with mesospheric wind motions, were used to Doppler-sort and then echo-locate individual scattering points. The three-dimensional location and radial velocity of each discrete scattering point was determined. Mean winds were then determined by a least squares fit to the radial velocities of the ensemble of scatterers.

  18. Short tandem repeat profiling: part of an overall strategy for reducing the frequency of cell misidentification.

    PubMed

    Nims, Raymond W; Sykes, Greg; Cottrill, Karin; Ikonomi, Pranvera; Elmore, Eugene

    2010-12-01

    The role of cell authentication in biomedical science has received considerable attention, especially within the past decade. This quality control attribute is now beginning to be given the emphasis it deserves by granting agencies and by scientific journals. Short tandem repeat (STR) profiling, one of a few DNA profiling technologies now available, is being proposed for routine identification (authentication) of human cell lines, stem cells, and tissues. The advantage of this technique over methods such as isoenzyme analysis, karyotyping, human leukocyte antigen typing, etc., is that STR profiling can establish identity to the individual level, provided that the appropriate number and types of loci are evaluated. To best employ this technology, a standardized protocol and a data-driven, quality-controlled, and publically searchable database will be necessary. This public STR database (currently under development) will enable investigators to rapidly authenticate human-based cultures to the individual from whom the cells were sourced. Use of similar approaches for non-human animal cells will require developing other suitable loci sets. While implementing STR analysis on a more routine basis should significantly reduce the frequency of cell misidentification, additional technologies may be needed as part of an overall authentication paradigm. For instance, isoenzyme analysis, PCR-based DNA amplification, and sequence-based barcoding methods enable rapid confirmation of a cell line's species of origin while screening against cross-contaminations, especially when the cells present are not recognized by the species-specific STR method. Karyotyping may also be needed as a supporting tool during establishment of an STR database. Finally, good cell culture practices must always remain a major component of any effort to reduce the frequency of cell misidentification. PMID:20927602

  19. Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations.

    PubMed

    Gao, Wang; Gao, Chengfa; Pan, Shuguo; Wang, Denghui; Deng, Jiadong

    2015-10-30

    The regional constellation of the BeiDou navigation satellite system (BDS) has been providing continuous positioning, navigation and timing services since 27 December 2012, covering China and the surrounding area. Real-time kinematic (RTK) positioning with combined BDS and GPS observations is feasible. Besides, all satellites of BDS can transmit triple-frequency signals. Using the advantages of multi-pseudorange and carrier observations from multi-systems and multi-frequencies is expected to be of much benefit for ambiguity resolution (AR). We propose an integrated AR strategy for medium baselines by using the combined GPS and BDS dual/triple-frequency observations. In the method, firstly the extra-wide-lane (EWL) ambiguities of triple-frequency system, i.e., BDS, are determined first. Then the dual-frequency WL ambiguities of BDS and GPS were resolved with the geometry-based model by using the BDS ambiguity-fixed EWL observations. After that, basic (i.e., L1/L2 or B1/B2) ambiguities of BDS and GPS are estimated together with the so-called ionosphere-constrained model, where the ambiguity-fixed WL observations are added to enhance the model strength. During both of the WL and basic AR, a partial ambiguity fixing (PAF) strategy is adopted to weaken the negative influence of new-rising or low-elevation satellites. Experiments were conducted and presented, in which the GPS/BDS dual/triple-frequency data were collected in Nanjing and Zhengzhou of China, with the baseline distance varying from about 28.6 to 51.9 km. The results indicate that, compared to the single triple-frequency BDS system, the combined system can significantly enhance the AR model strength, and thus improve AR performance for medium baselines with a 75.7% reduction of initialization time on average. Besides, more accurate and stable positioning results can also be derived by using the combined GPS/BDS system.

  20. Trinucleotide repeats at the FRAXF locus: Frequency and distribution in the general population

    SciTech Connect

    Holden, J.J.A.; Walker, M.

    1996-08-09

    FRAXF the third X-chromosomal fragile site to be cloned, has been shown to harbor a polymorphic compound triplet array: (GC-CGTC){sub n} (GCC){sub n}. Expansion and methylation of the GCC-repeat and the neighboring CpG-rich region result in chromosomal fragility. DNAs from 500 anonymous consecutive newborn males were examined to determine the incidence of various repeat numbers. The range of repeats was from 10-38, with the most common alleles having 14 (52.7%), 12 (16.6%), 21 (9.0%), and 22 (5.2%) triplets. Based on the distribution of repeat numbers, we suggest that the 21-repeat allele resulted from hairpin formation involving 7 GCC-repeats in a 14-repeat allele, accompanied by polymerase slippage. Examination of dinucleotide repeats near the FRAXF repeat will be important in testing this hypothesis. Since the clinical phenotype, if any, of FRAXF is unknown, this database will also be valuable for comparisons with repeat numbers in individuals from special populations. 20 refs., 1 fig., 1 tab.

  1. Poly(3-Hydroxybutyrate) Production in Repeated fed-Batch with Cell Recycle Using a Medium with low Carbon Source Concentration.

    PubMed

    Ienczak, Jaciane Lutz; Schmidt, Mélodi; Quines, Luci Kelin; Zanfonato, Kellen; da Cruz Pradella, José Geraldo; Schmidell, Willibaldo; de Aragao, Glaucia Maria Falcao

    2016-01-01

    Among approaches applied to obtain high productivity and low production costs in bioprocesses are high cell density and the use of low cost substrates. Usually low cost substrates, as waste/agroindustrial residues, have low carbon concentration, which leads to a difficulty in operating bioprocesses. Real time control of process for intracellular products is also difficult. The present study proposes a strategy of repeated fed-batch with cell recycle to attain high cell density of Cupriavidus necator and high poly(3-hydroxybutyrate) (P(3HB)) productivity, using a substrate with low carbon source concentration (90 g l(-1)). Also, the use of the oxygen uptake rate data was pointed out as an on line solution for process control, once P(3HB) is an intracellular product. The results showed that total biomass (X), residual biomass (Xr) and P(3HB) values at the end of the culture were 61.6 g l(-1), 19.3 g l(-1) and 42.4 g l(-1) respectively, equivalent to 68.8 % of P(3HB) in the cells, and P(3HB) productivity of 1.0 g l(-1) h(-1). Therefore, the strategy proposed was efficient to achieve high productivity and high polymer content from a medium with low carbon source concentration.

  2. Low frequency sound scattering from spherical assemblages of bubbles using effective medium theory.

    PubMed

    Hahn, Thomas R

    2007-12-01

    The determination of the acoustic field scattered by an underwater assembly of gas bubbles or similar resonant monopole scatterers is of considerable theoretical and practical interest. This problem is addressed from a theoretical point of view within the framework of the effective medium theory for the case of spherically shaped assemblages. Although being valid more generally, the effective medium theory is an ideal instrument to study multiple scattering effects such as low frequency collective resonances, acoustically coupled breathing modes of the entire assembly. Explicit expressions for the scattering amplitude and cross sections are derived, as well as closed form expressions for the resonance frequency and spectral shape of the fundamental collective mode utilizing analytical S-matrix methods. This approach allows, in principle, a simultaneous inversion for the assembly radius and void fraction directly from the scattering cross sections. To demonstrate the validity of the approach, the theory is applied to the example of idealized, spherically shaped schools of swim bladder bearing fish. The analytic results of the theory are compared to numerical first-principle benchmark computations and excellent agreement is found, even for densely packed schools and frequencies across the bladder resonance.

  3. Determination of medium electrical properties through full-wave modelling of frequency domain reflectrometry data

    NASA Astrophysics Data System (ADS)

    André, Frédéric; Lambot, Sébastien

    2015-04-01

    Accurate knowledge of the shallow soil properties is of prime importance in agricultural, hydrological and environmental engineering. During the last decade, numerous geophysical techniques, either invasive or resorting to proximal or remote sensing, have been developed and applied for quantitative characterization of soil properties. Amongst them, time domain reflectrometry (TDR) and frequency domain reflectometry (FDR) are recognized as standard techniques for the determination of soil dielectric permittivity and electrical conductivity, based on the reflected electromagnetic waves from a probe inserted into the soil. TDR data were first commonly analyzed in the time domain using methods considering only a part of the waveform information. Later, advancements have led to the possibility of analyzing the TDR signal through full-wave inverse modeling either in the time or the frequency domains. A major advantage of FDR compared to TDR is the possibility to increase the bandwidth, thereby increasing the information content of the data and providing more detailed characterization of the medium. Amongst the recent works in this field, Minet et al. (2010) developed a modeling procedure for processing FDR data based on an exact solution of Maxwell's equations for wave propagation in one-dimensional multilayered media. In this approach, the probe head is decoupled from the medium and is fully described by characteristic transfer functions. The authors successfully validated the method for homogeneous sand subject to a range of water contents. In the present study, we further validated the modelling approach using reference liquids with well-characterized frequency-dependent electrical properties. In addition, the FDR model was coupled with a dielectric mixing model to investigate the ability of retrieving water content, pore water electrical conductivity and sand porosity from inversion of FDR data acquired in sand subject to different water content levels. Finally, the

  4. Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations.

    PubMed

    Gao, Wang; Gao, Chengfa; Pan, Shuguo; Wang, Denghui; Deng, Jiadong

    2015-01-01

    The regional constellation of the BeiDou navigation satellite system (BDS) has been providing continuous positioning, navigation and timing services since 27 December 2012, covering China and the surrounding area. Real-time kinematic (RTK) positioning with combined BDS and GPS observations is feasible. Besides, all satellites of BDS can transmit triple-frequency signals. Using the advantages of multi-pseudorange and carrier observations from multi-systems and multi-frequencies is expected to be of much benefit for ambiguity resolution (AR). We propose an integrated AR strategy for medium baselines by using the combined GPS and BDS dual/triple-frequency observations. In the method, firstly the extra-wide-lane (EWL) ambiguities of triple-frequency system, i.e., BDS, are determined first. Then the dual-frequency WL ambiguities of BDS and GPS were resolved with the geometry-based model by using the BDS ambiguity-fixed EWL observations. After that, basic (i.e., L1/L2 or B1/B2) ambiguities of BDS and GPS are estimated together with the so-called ionosphere-constrained model, where the ambiguity-fixed WL observations are added to enhance the model strength. During both of the WL and basic AR, a partial ambiguity fixing (PAF) strategy is adopted to weaken the negative influence of new-rising or low-elevation satellites. Experiments were conducted and presented, in which the GPS/BDS dual/triple-frequency data were collected in Nanjing and Zhengzhou of China, with the baseline distance varying from about 28.6 to 51.9 km. The results indicate that, compared to the single triple-frequency BDS system, the combined system can significantly enhance the AR model strength, and thus improve AR performance for medium baselines with a 75.7% reduction of initialization time on average. Besides, more accurate and stable positioning results can also be derived by using the combined GPS/BDS system. PMID:26528977

  5. Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations

    PubMed Central

    Gao, Wang; Gao, Chengfa; Pan, Shuguo; Wang, Denghui; Deng, Jiadong

    2015-01-01

    The regional constellation of the BeiDou navigation satellite system (BDS) has been providing continuous positioning, navigation and timing services since 27 December 2012, covering China and the surrounding area. Real-time kinematic (RTK) positioning with combined BDS and GPS observations is feasible. Besides, all satellites of BDS can transmit triple-frequency signals. Using the advantages of multi-pseudorange and carrier observations from multi-systems and multi-frequencies is expected to be of much benefit for ambiguity resolution (AR). We propose an integrated AR strategy for medium baselines by using the combined GPS and BDS dual/triple-frequency observations. In the method, firstly the extra-wide-lane (EWL) ambiguities of triple-frequency system, i.e., BDS, are determined first. Then the dual-frequency WL ambiguities of BDS and GPS were resolved with the geometry-based model by using the BDS ambiguity-fixed EWL observations. After that, basic (i.e., L1/L2 or B1/B2) ambiguities of BDS and GPS are estimated together with the so-called ionosphere-constrained model, where the ambiguity-fixed WL observations are added to enhance the model strength. During both of the WL and basic AR, a partial ambiguity fixing (PAF) strategy is adopted to weaken the negative influence of new-rising or low-elevation satellites. Experiments were conducted and presented, in which the GPS/BDS dual/triple-frequency data were collected in Nanjing and Zhengzhou of China, with the baseline distance varying from about 28.6 to 51.9 km. The results indicate that, compared to the single triple-frequency BDS system, the combined system can significantly enhance the AR model strength, and thus improve AR performance for medium baselines with a 75.7% reduction of initialization time on average. Besides, more accurate and stable positioning results can also be derived by using the combined GPS/BDS system. PMID:26528977

  6. Breathing as a low frequency wave propagation in nonlinear elastic permeable medium

    NASA Astrophysics Data System (ADS)

    Kyriakou, Elizabeth; McKenzie, David R.; Suchowerska, Natalka; Fulton, Roger R.

    2007-05-01

    Breathing can be regarded as a type of low frequency wave propagation. Unlike sound propagation in open air, in breathing, the air compressibility is not as important as the flow of air, and to a first approximation the air can be regarded as incompressible. We have developed a one-dimensional analytical description of wave motion in a metamaterial consisting of a porous elastic medium contained within chambers, separated by plates with orifices representing the minor airways. The metamaterial is placed within a cylinder with impermeable sides representing the thorax, driven at one end by a piston representing the diaphragm. The incompressible air is able to escape from the top of the cylinder. The solutions to the wave equation have characteristics that depend on the values of permeability (defined by the size of the orifice in the plates), the Young's modulus of the elastic medium and the density of lung tissue. A ‘normal' regime is identified in which the strain of the medium near the diaphragm is large and the strain at the top of the cylinder near the outlet is small. An ‘abnormal' regime is also identified in which the opposite applies. A rapid transition between the two regimes can be caused by changing the parameters representing the lung tissue. This transition may represent the onset of a disease state such as asthma.

  7. Repeatability of Layered Corneal Pachymetry With the Artemis Very High-frequency Digital Ultrasound Arc-Scanner

    PubMed Central

    Reinstein, Dan Z.; Archer, Timothy J.; Gobbe, Marine; Silverman, Ronald H.; Coleman, D. Jackson

    2015-01-01

    Purpose To assess the three-dimensional repeatability of thickness measurements for epithelium, stroma, cornea, flap, and residual stromal bed using the Artemis very high-frequency (VHF) digital ultrasound arc-scanner (ArcScan Inc). Methods Five consecutive measurements were obtained for 10 eyes of 10 patients 1 year after LASIK using the Artemis VHF digital ultrasound arc-scanner across the central 10-mm diameter of the cornea. Repeatability analysis was performed for thickness measurements for each corneal layer—epithelium, stroma, cornea, flap, and residual stromal bed. The standard deviation of repeated measurements (point-repeatability) was calculated for each measurement location in 0.1-mm steps for the 10 × 10-mm matrix. The pooled standard deviation of the point-repeatability for each measurement location within the central 1-, 2-, and 3-mm radius was calculated (region-repeatability). The corneal thickness of the baseline scan set was compared to that of subsequent scan sets within the same session and plotted over time to assess any possible hydration effects of the immersion technique. Results The repeatability at the corneal vertex was 0.58 μm for epithelium, 1.78 μm for stroma, 1.68 μm for cornea, 1.68 μm for flap, and 2.27 μm for residual stromal bed. The region-repeatability within the central 1-mm radius was 1.01 μm for epithelium, 3.44 μm for stroma, 3.35 μm for cornea, 2.81 μm for flap, and 3.97 μm for residual stromal bed. The mean difference in corneal thickness from the baseline value was within 1.25 μm for each of the subsequent four scan sets over a 5-minute immersion period. Conclusions Layered pachymetry of the epithelium, stroma, cornea, flap, and residual stromal bed showed high repeatability with the Artemis VHF digital ultrasound arc-scanner. The high repeatability validates the use of the Artemis for in vivo layered pachymetry. PMID:19928698

  8. Experimental tests of the generation mechanism of auroral medium frequency burst radio emissions

    NASA Astrophysics Data System (ADS)

    Bunch, N. L.; Labelle, J.; Weatherwax, A. T.; Hughes, J. M.; Lummerzheim, D.

    2009-09-01

    Medium frequency (MF) burst is an impulsive auroral radio emission at 1.3-4.5 MHz commonly detected by ground-based instruments for a few minutes at substorm onsets. It is thought to arise from mode conversion radiation. The Dartmouth College MF radio interferometer at Toolik Field Station, Alaska (68.51° invariant latitude), measured spectra, amplitudes, and directions of arrival (DOA) of 47 MF burst events during 2006-2007 and 49 events during 2007-2008. Statistical analysis of these events shows that they come predominantly from the south and east of Toolik, as expected because propagation conditions are more favorable poleward and westward of the active auroral arcs than equatorward or eastward during premidnight (westward moving) substorm onset activity. Case studies of a selected MF burst event on 20 November 2007 show that motions of the radio emissions qualitatively track the motions of auroral arcs simultaneously observed with all-sky camera. Case studies of DOA data of selected MF burst events on 31 January and 20 November 2007 show that higher-frequency components of MF burst arrive at higher elevation angles than lower-frequency components. Statistical studies confirm this trend. Ray-tracing analysis shows that this trend implies that sources of the higher-frequency components of the MF burst are at higher altitudes than those of the lower-frequency components. The analysis also shows that the MF burst comes from the bottomside F region ionosphere. These observations are consistent with a mechanism of MF burst emission whereby the emissions originate from mode conversion of Langmuir or upper hybrid waves excited over a range of altitudes in the bottomside F region.

  9. A Hybrid Approach for Efficient Modeling of Medium-Frequency Propagation in Coal Mines

    PubMed Central

    Brocker, Donovan E.; Sieber, Peter E.; Waynert, Joseph A.; Li, Jingcheng; Werner, Pingjuan L.; Werner, Douglas H.

    2015-01-01

    An efficient procedure for modeling medium frequency (MF) communications in coal mines is introduced. In particular, a hybrid approach is formulated and demonstrated utilizing ideal transmission line equations to model MF propagation in combination with full-wave sections used for accurate simulation of local antenna-line coupling and other near-field effects. This work confirms that the hybrid method accurately models signal propagation from a source to a load for various system geometries and material compositions, while significantly reducing computation time. With such dramatic improvement to solution times, it becomes feasible to perform large-scale optimizations with the primary motivation of improving communications in coal mines both for daily operations and emergency response. Furthermore, it is demonstrated that the hybrid approach is suitable for modeling and optimizing large communication networks in coal mines that may otherwise be intractable to simulate using traditional full-wave techniques such as moment methods or finite-element analysis. PMID:26478686

  10. Superconducting radio-frequency cavities made from medium and low-purity niobium ingots

    NASA Astrophysics Data System (ADS)

    Ciovati, Gianluigi; Dhakal, Pashupati; Myneni, Ganapati R.

    2016-06-01

    Superconducting radio-frequency cavities made of ingot niobium with residual resistivity ratio (RRR) greater than 250 have proven to have similar or better performance than fine-grain Nb cavities of the same purity, after standard processing. The high purity requirement contributes to the high cost of the material. As superconducting accelerators operating in continuous-wave typically require cavities to operate at moderate accelerating gradients, using lower purity material could be advantageous not only to reduce cost but also to achieve higher Q 0-values. In this contribution we present the results from cryogenic RF tests of 1.3-1.5 GHz single-cell cavities made of ingot Nb of medium (RRR = 100-150) and low (RRR = 60) purity from different suppliers. Cavities made of medium-purity ingots routinely achieved peak surface magnetic field values greater than 70 mT with an average Q 0-value of 2 × 1010 at 2 K after standard processing treatments. The performances of cavities made of low-purity ingots were affected by significant pitting of the surface after chemical etching.

  11. Superconducting radio-frequency cavities made from medium and low-purity niobium ingots

    DOE PAGES

    Ciovati, Gianluigi; Dhakal, Pashupati; Myneni, Ganapati R.

    2016-04-07

    Superconducting radio-frequency cavities made of ingot niobium with residual resistivity ratio (RRR) greater than 250 have proven to have similar or better performance than fine-grain Nb cavities of the same purity, after standard processing. The high purity requirement contributes to the high cost of the material. As superconducting accelerators operating in continuous-wave typically require cavities to operate at moderate accelerating gradients, using lower purity material could be advantageous not only to reduce cost but also to achieve higher Q0-values. In this contribution we present the results from cryogenic RF tests of 1.3–1.5 GHz single-cell cavities made of ingot Nb ofmore » medium (RRR = 100–150) and low (RRR = 60) purity from different suppliers. Cavities made of medium-purity ingots routinely achieved peak surface magnetic field values greater than 70 mT with an average Q0-value of 2 × 1010 at 2 K after standard processing treatments. As a result, the performances of cavities made of low-purity ingots were affected by significant pitting of the surface after chemical etching.« less

  12. Propagation of the two-frequency coherence function in an inhomogeneous background random medium

    NASA Astrophysics Data System (ADS)

    Kalugin, Alexander; Bronshtein, Alexander; Mazar, Reuven

    2004-07-01

    The spatial and temporal structures of time-dependent signals can be appreciably affected by random changes of the parameters of the medium characteristic of almost all geophysical environments. The dispersive properties of random media cause distortions in the propagating signal, particularly in pulse broadening and time delay. When there is also spatial variation of the background refractive index, the observer can be accessed by a number of background rays. In order to compute the pulse characteristics along each separate ray, there is a need to know the behaviour of the two-frequency mutual coherence function. In this work, we formulate the equation of the two-frequency mutual coherence function along a curved background ray trajectory. To solve this equation, a recently developed reference-wave method is applied. This method is based on embedding the problem into a higher dimensional space and is accompanied by the introduction of additional coordinates. Choosing a proper transform of the extended coordinate system allows us to emphasize 'fast' and 'slow' varying coordinates which are consequently normalized to the scales specific to a given type of problem. Such scaling usually reveals the important expansion parameters defined as ratios of the characteristic scales and allows us to present the proper ordering of terms in the desired equation. The performance of the main order solution is demonstrated for the homogeneous background case when the transverse structure function of the medium can be approximated by a quadratic term. This article is dedicated to the memory of Professor Reuven Mazar, a top notch scientist, whose creativity influenced many random media researchers. Professor Mazar passed away suddenly a few weeks before the publication of this paper.

  13. Forest canopy height estimation using double-frequency repeat pass interferometry

    NASA Astrophysics Data System (ADS)

    Karamvasis, Kleanthis; Karathanassi, Vassilia

    2015-06-01

    In recent years, many efforts have been made in order to assess forest stand parameters from remote sensing data, as a mean to estimate the above-ground carbon stock of forests in the context of the Kyoto protocol. Synthetic aperture radar interferometry (InSAR) techniques have gained traction in last decade as a viable technology for vegetation parameter estimation. Many works have shown that forest canopy height, which is a critical parameter for quantifying the terrestrial carbon cycle, can be estimated with InSAR. However, research is still needed to understand further the interaction of SAR signals with forest canopy and to develop an operational method for forestry applications. This work discusses the use of repeat pass interferometry with ALOS PALSAR (L band) HH polarized and COSMO Skymed (X band) HH polarized acquisitions over the Taxiarchis forest (Chalkidiki, Greece), in order to produce accurate digital elevation models (DEMs) and estimate canopy height with interferometric processing. The effect of wavelength-dependent penetration depth into the canopy is known to be strong, and could potentially lead to forest canopy height mapping using dual-wavelength SAR interferometry at X- and L-band. The method is based on scattering phase center separation at different wavelengths. It involves the generation of a terrain elevation model underneath the forest canopy from repeat-pass L-band InSAR data as well as the generation of a canopy surface elevation model from repeat pass X-band InSAR data. The terrain model is then used to remove the terrain component from the repeat pass interferometric X-band elevation model, so as to enable the forest canopy height estimation. The canopy height results were compared to a field survey with 6.9 m root mean square error (RMSE). The effects of vegetation characteristics, SAR incidence angle and view geometry, and terrain slope on the accuracy of the results have also been studied in this work.

  14. High frequency of the expanded C9ORF72 hexanucleotide repeat in familial and sporadic Greek ALS patients

    PubMed Central

    Mok, Kin Y.; Koutsis, Georgios; Schottlaender, Lucia V.; Polke, James; Panas, Marios; Houlden, Henry

    2012-01-01

    An intronic expansion of a hexanucleotide GGGGCC repeat in the C9ORF72 gene has recently been shown to be an important cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in familial and sporadic cases. The frequency has only been defined in a small number of populations where the highest sporadic rate was identified in Finland (21.1%) and the lowest in mainland Italy (4.1%). We examined the C9ORF72 expansion in a series of 146 Greek ALS cases, 10.95% (n = 16) of cases carried the pathological expansion defined as greater than 30 repeats. In the 10 familial ALS probands, 50% (n = 5) of them carried a pathologically large expansion. In the remaining 136 sporadic ALS cases, 11 were carriers (8.2%). None of the 228 Greek controls carried an expanded repeat. The phenotype of our cases was spinal (13/16) or bulbar (3/16) ALS, the familial cases were all spinal ALS and none of our cases had behavioral frontotemporal dementia. Expansions in the C9ORF72 gene therefore represent a common cause of ALS in Greece and this test will be diagnostically very important to implement in the Greek population. The frequency is higher than other populations with the exception of Finland and this may be due to Greece being a relatively isolated population. PMID:22445326

  15. Simulation and Measurement of Medium-Frequency Signals Coupling From a Line to a Loop Antenna

    PubMed Central

    Damiano, Nicholas W.; Li, Jingcheng; Zhou, Chenming; Brocker, Donovan E.; Qin, Yifeng; Werner, Douglas H.; Werner, Pingjuan L.

    2016-01-01

    The underground-mining environment can affect radio-signal propagation in various ways. Understanding these effects is especially critical in evaluating communications systems used during normal mining operations and during mine emergencies. One of these types of communications systems relies on medium-frequency (MF) radio frequencies. This paper presents the simulation and measurement results of recent National Institute for Occupational Safety and Health (NIOSH) research aimed at investigating MF coupling between a transmission line (TL) and a loop antenna in an underground coal mine. Two different types of measurements were completed: 1) line-current distribution and 2) line-to-antenna coupling. Measurements were taken underground in an experimental coal mine and on a specially designed surface test area. The results of these tests are characterized by current along a TL and voltage induced in the loop from a line. This paper concludes with a discussion of issues for MF TLs. These include electromagnetic fields at the ends of the TL, connection of the ends of the TL, the effect of other conductors underground, and the proximity of coal or earth. These results could help operators by providing examples of these challenges that may be experienced underground and a method by which to measure voltage induced by a line. PMID:27784954

  16. Auroral Radio Emission Direction of Arrival Studies of Simultaneous Medium Frequency Burst and Auroral Hiss

    NASA Astrophysics Data System (ADS)

    Broughton, M.; Labelle, J. W.

    2010-12-01

    The auroral zone is the source of multiple kinds of radio emissions that can be observed on the ground. The study of radio emissions offers a way to remotely sense space plasma processes and, in the case of auroral emissions, to use the auroral ionosphere as a large-scale plasma physics laboratory. Medium frequency (MF) burst is an impulsive radio emission at 1.5-4.5 MHz observed on the ground. Its generation mechanism is unknown, and it is often associated with the onset of substorms. Auroral hiss is an impulsive emission observed on the ground at frequencies up to 1 MHz and is also associated with substorm onset. LaBelle et al. [1997] reported a temporal relationship between MF burst and auroral hiss. Multiple impulses of both MF burst and auroral hiss occurred simultaneously over a time period that in certain cases lasted tens of minutes. While the temporal relationship on the timescale of seconds is well established, the spatial relationship between MF burst and auroral hiss has yet to be investigated. Dartmouth College currently operates a broadband (0-5 MHz) four-element radio interferometer at Toolik Field Station in Alaska (68° 38' N, 149° 36' W, 68.5° magnetic latitude) in order to study the direction of arrival (DOA) of radio emissions. Since the antenna spacing is 50 meters, the interferometer is optimized for DOA measurements of MF bursts. However, in certain cases, it can provide the DOA for the high-frequency portion of impulsive auroral hiss. We present two case studies that represent the first simultaneous DOA measurements of impulsive auroral hiss and MF burst. On March 4, 2010, the DOA of MF burst was predominantly from 30 degrees south of east, an observation consistent with the statistical work performed by Bunch et al. [2009]. Simultaneous DOA measurements of the high-frequency portion of auroral hiss also showed the DOA as approximately 30 degrees south of east but with greater scatter in the data. The second case study, which involved an

  17. [Removal of substances with low and medium molecular weight by repeated application of C-DAK-capillary dialysers].

    PubMed

    Gál, G; Gróf, J

    1979-01-01

    The capillary dialysator type C-DAK (Cordis Dow Mod. 4) can according to the regeneration method described be used three times as valid membrane for the elimination of the small as well as of the medium-sized molecules from the serum in the same patient.

  18. Design of flat lens-like graded index medium by photonic crystals: Exploring both low and high frequency regimes

    NASA Astrophysics Data System (ADS)

    Turduev, M.; Giden, I. H.; Kurt, H.

    2015-03-01

    In this manuscript, we propose the design of an inhomogeneous artificially created graded index (GRIN) medium to enrich the optical device functionalities of light by using periodic all-dielectric materials. Continuous GRIN profile with hyperbolic secant index distribution is approximated using two-dimensional photonic crystal (2D PC) dielectric rods with a fixed refractive index. The locations of each individual cell that contain dielectric rods of certain radii are determined based on the results of the frequency domain analysis. The desired index distribution is attained at long wavelengths using dispersion engineering approach. The frequency response of the transmission spectrum exhibits high transmission windows appearing at both larger and smaller wavelengths regions. Two regions are separated by a local band gap that blocks the incident light for a certain frequency interval. Light manipulation characteristics such as focusing, de-focusing and collimation are systematically and quantitatively compared for artificially designed GRIN medium within low and high frequency regimes. We show different field manipulation capabilities and focal point movement dynamics of the GRIN medium by special adjustment of the length of the structure. In addition, an analytical formulation based on ray theory is derived to investigate the focusing, de-focusing and collimation properties of proposed GRIN medium. The analytical approach utilizes Ray theory and computational tools are based on plane wave expansion and finite-difference time-domain methods. Implementing the GRIN medium by periodic optical materials provides frequency selectivity and strong focusing effects at higher frequency region. The designed structure can be used in integrated nanophotonics as a compact optical element with flat surfaces.

  19. 78 FR 42102 - Termination of Radiotelephone Medium Frequency 2182 kHz Watchkeeping, 2187.5 kHz Digital...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-15

    ... SECURITY Coast Guard Termination of Radiotelephone Medium Frequency 2182 kHz Watchkeeping, 2187.5 kHz Digital Selective Calling Channel Guard, and 2670 kHz Broadcasts ACTION: Notice. SUMMARY: The United States Coast Guard is announcing that it will no longer maintain a watch on 2182 kHz, will no...

  20. Repeated exposure to high-frequency spanking and child externalizing behavior across the first decade: a moderating role for cumulative risk.

    PubMed

    MacKenzie, Michael J; Nicklas, Eric; Brooks-Gunn, Jeanne; Waldfogel, Jane

    2014-12-01

    This study used the Fragile Families and Child Well-Being Study to examine the effects of repeated exposure to harsh parenting on child externalizing behavior across the first decade of life, and a moderating role for cumulative ecological risk. Maternal report of harsh parenting, defined as high frequency spanking, was assessed at age 1, 3, 5, and 9, along with child externalizing at age 9 (N=2,768). Controlling for gender, race, maternal nativity, and city of residence, we found a cumulative risk index to significantly moderate the effects of repeated harsh parenting on child behavior, with the effects of repeated high-frequency spanking being amplified for those experiencing greater levels of cumulative risk. Harsh parenting, in the form of high frequency spanking, remains a too common experience for children, and results demonstrate that the effects of repeated exposure to harsh parenting across the first decade are amplified for those children already facing the most burden.

  1. Influence of a contaminated fish diet on germline expanded-simple-tandem-repeat mutation frequency in mice.

    PubMed

    Somers, Christopher M; Valdes, Eduardo V; Kjoss, Victoria A; Vaillancourt, Andre L; Quinn, James S

    2008-04-01

    Herring gulls (Larus argentatus) in polluted areas on the North American Great Lakes were previously shown to have elevated germline mutation frequencies at minisatellite DNA loci. Airborne or dietary contaminants likely caused induced mutations, but the importance of each exposure type was unknown. Follow-up experiments with lab mice determined that air pollution significantly induced germline mutations; however, an evaluation of mutations induced by the diet of herring gulls has not yet been conducted. To address this issue, we fed mice a high-fish diet (58% wet mass) of the most common prey species for herring gulls nesting in Hamilton Harbour, a polluted industrial area on Lake Ontario. We bred the mice and screened pedigrees for germline mutations at expanded-simple-tandem-repeat (ESTR) DNA loci. Mutation frequencies were compared to those in a reference group that was fed fish from Atlantic Canada, and a control group that was fed commercial chow. Germline mutation frequencies were highest in mice fed contaminated fish, but were only marginally or not significantly affected by diet treatment. Statistical power to detect differences among treatment groups was low, and the effect of diet may have more clearly emerged if larger sample sizes were available. Levels of organic pollutants in the fish from Hamilton Harbour were higher than those from Atlantic Canada, but their ability to induce ESTR mutations is unknown. Our findings suggest that a contaminated fish diet may contribute to the elevated germline mutation frequencies observed previously in gulls at this site, but air pollution is likely a more important route of exposure.

  2. Algebraic processing technique for extracting frequency-dependent shear-wave splitting parameters in an anisotropic medium

    NASA Astrophysics Data System (ADS)

    Han, Kai-Feng; Zeng, Xin-Wu

    2011-06-01

    Based on the dual source cumulative rotation technique in the time-domain proposed by Zeng and MacBeth (1993), a new algebraic processing technique for extracting shear-wave splitting parameters from multi-component VSP data in frequency-dependent medium has been developed. By using this dual source cumulative rotation technique in the frequency-domain (DCTF), anisotropic parameters, including polarization direction of the shear-waves and timedelay between the fast and slow shear-waves, can be estimated for each frequency component in the frequency domain. It avoids the possible error which comes from using a narrow-band filter in the current commonly used method. By using synthetic seismograms, the feasibility and validity of the technique was tested and a comparison with the currently used method was also given. The results demonstrate that the shear-wave splitting parameters frequency dependence can be extracted directly from four-component seismic data using the DCTF. In the presence of larger scale fractures, substantial frequency dependence would be found in the seismic frequency range, which implies that dispersion would occur at seismic frequencies. Our study shows that shear-wave anisotropy decreases as frequency increases.

  3. Instantaneous Real-Time Kinematic Decimeter-Level Positioning with BeiDou Triple-Frequency Signals over Medium Baselines

    PubMed Central

    He, Xiyang; Zhang, Xiaohong; Tang, Long; Liu, Wanke

    2015-01-01

    Many applications, such as marine navigation, land vehicles location, etc., require real time precise positioning under medium or long baseline conditions. In this contribution, we develop a model of real-time kinematic decimeter-level positioning with BeiDou Navigation Satellite System (BDS) triple-frequency signals over medium distances. The ambiguities of two extra-wide-lane (EWL) combinations are fixed first, and then a wide lane (WL) combination is reformed based on the two EWL combinations for positioning. Theoretical analysis and empirical analysis is given of the ambiguity fixing rate and the positioning accuracy of the presented method. The results indicate that the ambiguity fixing rate can be up to more than 98% when using BDS medium baseline observations, which is much higher than that of dual-frequency Hatch-Melbourne-Wübbena (HMW) method. As for positioning accuracy, decimeter level accuracy can be achieved with this method, which is comparable to that of carrier-smoothed code differential positioning method. Signal interruption simulation experiment indicates that the proposed method can realize fast high-precision positioning whereas the carrier-smoothed code differential positioning method needs several hundreds of seconds for obtaining high precision results. We can conclude that a relatively high accuracy and high fixing rate can be achieved for triple-frequency WL method with single-epoch observations, displaying significant advantage comparing to traditional carrier-smoothed code differential positioning method. PMID:26703614

  4. Instantaneous Real-Time Kinematic Decimeter-Level Positioning with BeiDou Triple-Frequency Signals over Medium Baselines.

    PubMed

    He, Xiyang; Zhang, Xiaohong; Tang, Long; Liu, Wanke

    2015-01-01

    Many applications, such as marine navigation, land vehicles location, etc., require real time precise positioning under medium or long baseline conditions. In this contribution, we develop a model of real-time kinematic decimeter-level positioning with BeiDou Navigation Satellite System (BDS) triple-frequency signals over medium distances. The ambiguities of two extra-wide-lane (EWL) combinations are fixed first, and then a wide lane (WL) combination is reformed based on the two EWL combinations for positioning. Theoretical analysis and empirical analysis is given of the ambiguity fixing rate and the positioning accuracy of the presented method. The results indicate that the ambiguity fixing rate can be up to more than 98% when using BDS medium baseline observations, which is much higher than that of dual-frequency Hatch-Melbourne-Wübbena (HMW) method. As for positioning accuracy, decimeter level accuracy can be achieved with this method, which is comparable to that of carrier-smoothed code differential positioning method. Signal interruption simulation experiment indicates that the proposed method can realize fast high-precision positioning whereas the carrier-smoothed code differential positioning method needs several hundreds of seconds for obtaining high precision results. We can conclude that a relatively high accuracy and high fixing rate can be achieved for triple-frequency WL method with single-epoch observations, displaying significant advantage comparing to traditional carrier-smoothed code differential positioning method. PMID:26703614

  5. Antioxidant responses in estuarine invertebrates exposed to repeated oil spills: Effects of frequency and dosage in a field manipulative experiment.

    PubMed

    Sandrini-Neto, Leonardo; Pereira, Letícia; Martins, César C; Silva de Assis, Helena C; Camus, Lionel; Lana, Paulo C

    2016-08-01

    We have experimentally investigated the effects of repeated diesel spills on the bivalve Anomalocardia brasiliana, the gastropod Neritina virginea and the polychaete Laeonereis culveri, by monitoring the responses of oxidative stress biomarkers in a subtropical estuary. Three frequencies of exposure events were compared against two dosages of oil in a factorial experiment with asymmetrical controls. Hypotheses were tested to distinguish between (i) the overall effect of oil spills, (ii) the effect of diesel dosage via different exposure regimes, and (iii) the effect of time since last spill. Antioxidant defense responses and oxidative damage in the bivalve A. brasiliana and the polychaete L. culveri were overall significantly affected by frequent oil spills compared to undisturbed controls. The main effects of diesel spills on both species were the induction of SOD and GST activities, a significant increase in LPO levels and a decrease in GSH concentration. N. virginea was particularly tolerant to oil exposure, with the exception of a significant GSH depletion. Overall, enzymatic activities and oxidative damage in A. brasiliana and L. culveri were induced by frequent low-dosage spills compared to infrequent high-dosage spills, although the opposite pattern was observed for N. virginea antioxidant responses. Antioxidant responses in A. brasiliana and L. culveri were not affected by timing of exposure events. However, our results revealed that N. virginea might have a delayed response to acute high-dosage exposure. Experimental in situ simulations of oil exposure events with varying frequencies and intensities provide a useful tool for detecting and quantifying environmental impacts. In general, antioxidant biomarkers were induced by frequent low-dosage exposures compared to infrequent high-dosage ones. The bivalve A. brasiliana and the polychaete L. culveri are more suitable sentinels due to their greater responsiveness to oil and also to their wider geographical

  6. Antioxidant responses in estuarine invertebrates exposed to repeated oil spills: Effects of frequency and dosage in a field manipulative experiment.

    PubMed

    Sandrini-Neto, Leonardo; Pereira, Letícia; Martins, César C; Silva de Assis, Helena C; Camus, Lionel; Lana, Paulo C

    2016-08-01

    We have experimentally investigated the effects of repeated diesel spills on the bivalve Anomalocardia brasiliana, the gastropod Neritina virginea and the polychaete Laeonereis culveri, by monitoring the responses of oxidative stress biomarkers in a subtropical estuary. Three frequencies of exposure events were compared against two dosages of oil in a factorial experiment with asymmetrical controls. Hypotheses were tested to distinguish between (i) the overall effect of oil spills, (ii) the effect of diesel dosage via different exposure regimes, and (iii) the effect of time since last spill. Antioxidant defense responses and oxidative damage in the bivalve A. brasiliana and the polychaete L. culveri were overall significantly affected by frequent oil spills compared to undisturbed controls. The main effects of diesel spills on both species were the induction of SOD and GST activities, a significant increase in LPO levels and a decrease in GSH concentration. N. virginea was particularly tolerant to oil exposure, with the exception of a significant GSH depletion. Overall, enzymatic activities and oxidative damage in A. brasiliana and L. culveri were induced by frequent low-dosage spills compared to infrequent high-dosage spills, although the opposite pattern was observed for N. virginea antioxidant responses. Antioxidant responses in A. brasiliana and L. culveri were not affected by timing of exposure events. However, our results revealed that N. virginea might have a delayed response to acute high-dosage exposure. Experimental in situ simulations of oil exposure events with varying frequencies and intensities provide a useful tool for detecting and quantifying environmental impacts. In general, antioxidant biomarkers were induced by frequent low-dosage exposures compared to infrequent high-dosage ones. The bivalve A. brasiliana and the polychaete L. culveri are more suitable sentinels due to their greater responsiveness to oil and also to their wider geographical

  7. Non-repeatable science: assessing the frequency of voucher specimen deposition reveals that most arthropod research cannot be verified

    PubMed Central

    2015-01-01

    Scientific findings need to be verifiable and grounded in repeatability. With specimen-level research this is in part achieved with the deposition of voucher specimens. These are labeled, curated, data-based specimens that have been deposited in a collection or museum, available for verification of the work and to ensure researchers are calling the same taxa by the same names. Voucher specimens themselves are the subject of research, from the discovery of new species by taxonomists to ecologists documenting historical records of invasive species. Our objective was to quantify the frequency of voucher specimen deposition in biodiversity and community ecology research through a survey of the peer-reviewed literature about arthropods, from 1989 until 2014. Overall rates of voucher deposition were alarmingly low, at under 25%. This rate increased significantly over time, with 35% of papers reporting on vouchers in 2014. Relative to the global mean, entomological research had a significantly higher rate of voucher deposition (46%), whereas researchers studying crustaceans deposited vouchers less than 6% of the time, significantly less than the mean. Researchers working in museums had a significantly higher frequency of voucher deposition. Our results suggest a significant culture shift about the process of vouchering specimens is required. There must be more education and mentoring about voucher specimens within laboratories and across different fields of study. Principal investigators and granting agencies need a proactive approach to ensuring specimen-level data are properly, long-term curated. Editorial boards and journals can also adopt policies to ensure papers are published only if explicit statements about the deposition of voucher specimens is provided. Although the gap is significant, achieving a higher rate of voucher specimen deposition is a worthy goal to ensure all research efforts are preserved for future generations. PMID:26339546

  8. Repeatability and interobserver reproducibility of Artemis-2 high-frequency ultrasound in determination of human corneal thickness

    PubMed Central

    Ogbuehi, Kelechi C; Osuagwu, Uchechukwu L

    2012-01-01

    Background The purpose of this study was to assess the repeatability and limits of agreement of corneal thickness values measured by a high-frequency ultrasound (Artemis-2), hand-held ultrasound pachymeter (DGH-500) and a specular microscope (SP-3000P). Methods Central corneal thickness (CCT) was analyzed in this prospective randomized study that included 32 patients (18 men and 14 women) aged 21–24 years. Measurements were obtained in two sessions, one week apart, by two examiners with three devices in a randomized order. Nine measurements were taken (three with each device) on one randomly selected eye of each patient in each measurement session. The coefficient of repeatability and interobserver reproducibility for the values of each method were calculated. The limits of agreement between techniques were also evaluated. Results There were no significant differences in CCT values between sessions for each of the three devices (P > 0.05). The repeatability coefficients for the Artemis-2 (±8 μm/±9 μm) were superior to those of the SP-3000P (±9 μm/±11 μm) and DGH 500 (±12 μm/±12 μm) in session 1/session 2 respectively, while the interobserver reproducibility index (differences between session 1 and session 2) was superior for the SP-3000P (±17 μm) with respect to DHG-500 (±29 μm) and the Artemis-2 (±31 μm). In session 1 and session 2, the limits of agreement between the techniques were 35 μm to −31 μm and 34 to −20 μm, respectively, for DGH-500 versus Artemis-2, 73 μm to 3 μm and 60 μm to 9 μm for Artemis-2 versus SP-3000P, and 58 μm to 22 μm and 72 μm to 10 μm for DGH-500 versus SP-3000P comparisons. The DGH-500 and Artemis-2 gave similar values (P > 0.05) in both sessions, but both (Artemis-2 and DGH-500) values were significantly greater than that of the SP-3000P (P < 0.05) in both sessions. Conclusion Repeatability was comparably good for the three techniques. However, interobserver reproducibility was approximately twice as

  9. Medium-frequency impulsive-thrust-activated liquid hydrogen reorientation with Geyser

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Shyu, K. L.

    1992-01-01

    Efficient technique are studied for accomplishing propellant resettling through the minimization of propellant usage through impulsive thrust. A comparison between the use of constant-thrust and impulsive-thrust accelerations for the activation of propellant resettlement shows that impulsive thrust is superior to constant thrust for liquid reorientation in a reduced-gravity environment. This study shows that when impulsive thrust with 0.1-1.0-, and 10-Hz frequencies for liquid-fill levels in the range between 30-80 percent is considered, the selection of 1.0-Hz-frequency impulsive thrust over the other frequency ranges of impulsive thrust is the optimum. Characteristics of the slosh waves excited during the course of 1.0-Hz-frequency impulsive-thrust liquid reorientation were also analyzed.

  10. Local oscillator induced degradation of medium-term stability in passive atomic frequency standards

    NASA Technical Reports Server (NTRS)

    Dick, G. John; Prestage, John D.; Greenhall, Charles A.; Maleki, Lute

    1990-01-01

    As the performance of passive atomic frequency standards improves, a new limitation is encountered due to frequency fluctuations in an ancillary local oscillator (L.O.). The effect is due to time variation in the gain of the feedback which compensates L.O. frequency fluctuations. The high performance promised by new microwave and optical trapped ion standards may be severely compromised by this effect. Researchers present an analysis of this performance limitation for the case of sequentially interrogated standards. The time dependence of the sensitivity of the interrogation process to L.O. frequency fluctuations is evaluated for single-pulse and double-pulse Ramsey RF interrogation and for amplitude modulated pulses. The effect of these various time dependencies on performance of the standard is calculated for an L.O. with frequency fluctuations showing a typical 1/f spectral density. A limiting 1/sq. root gamma dependent deviation of frequency fluctuations is calculated as a function of pulse lengths, dead time, and pulse overlap. Researchers also present conceptual and hardware-oriented solutions to this problem which achieve a much more nearly constant sensitivity to L.O. fluctuations. Solutions involve use of double-pulse interrogation; alternate interrogation of multiple traps so that the dead time of one trap can be covered by operation of the other; and the use of double-pulse interrogation for two traps, so that during the time of the RF pulses, the increasing sensitivity of one trap tends to compensate for the decreasing sensitivity of the other. A solution making use of amplified-modulated pulses is also presented which shows nominally zero time variation.

  11. Direction of Arrival Studies of Medium Frequency Burst Radio Emissions at Toolik Lake, AK

    NASA Astrophysics Data System (ADS)

    Bunch, N.; Labelle, J.; Weatherwax, A.; Lummerzheim, D.; Stenbaek-Nielsen, H.

    2008-05-01

    MF burst is an impulsive radio emission of auroral origin, which can be detected by ground-based instruments at frequencies between 1,300 and 4,500kHz. MF burst has been shown to be associated with substorm onset, but its exact generation mechanism remains unknown, although it is thought to arise from mode conversion radiation [see review by LaBelle and Treumann, 2002] . In search of the generation mechanism of this emission, Dartmouth College has deployed radio interferometers in Alaska, Northern Canada, Greenland, and Antarctica, including a three-element interferometer deployed to Toolik Field Station in Alaska during the summer of 2006. This instrument measured spectra, amplitudes and directions of arrival (DOA's) of over 47 MF burst events between November 30, 2006 and May 26, 2007. These data represent the first DOA measurements of impulsive MF burst, of which selected case studies were presented at the Fall 2007 AGU conference. Here we present a statistical survey of all 47 events as well as detailed analysis of three events occurring on: Mar 5, Mar 23, and Nov 20, 2007. For the statistical survey, we present distributions of DOA as a function of local time and frequency. In each case study we analyze the direction of arrival of the emissions as a function of both time and frequency within each event. The time variations will be compared with the time variations of optical auroral forms simultaneously measured with all-sky cameras. The dependence of the arrival direction on frequency enables a significant test of the generation mechanism whereby the waves are emitted at the local plasma or upper hybrid frequency in the topside ionosphere, predicting that higher frequencies should originate at lower altitudes. These three events have been selected because All-Sky camera data are available at these times from Toolik Lake and Fort Yukon, Alaska. These are critical both for identifying which optical features are associated with the radio emissions as well as for

  12. Nonlinear Stress/Strain Behavior of a Synthetic Porous Medium at Seismic Frequencies

    NASA Astrophysics Data System (ADS)

    Roberts, P. M.; Ibrahim, R. H.

    2008-12-01

    Laboratory experiments on porous core samples have shown that seismic-band (100 Hz or less) mechanical, axial stress/strain cycling of the porous matrix can influence the transport behavior of fluids and suspended particles during steady-state fluid flow through the cores. In conjunction with these stimulated transport experiments, measurements of the applied dynamic axial stress/strain were made to investigate the nonlinear mechanical response of porous media for a poorly explored range of frequencies from 1 to 40 Hz. A unique core-holder apparatus that applies low-frequency mechanical stress/strain to 2.54-cm-diameter porous samples during constant-rate fluid flow was used for these experiments. Applied stress was measured with a load cell in series with the source and porous sample, and the resulting strain was measured with an LVDT attached to the core face. A synthetic porous system consisting of packed 1-mm-diameter glass beads was used to investigate both stress/strain and stimulated mass-transport behavior under idealized conditions. The bead pack was placed in a rubber sleeve and static confining stresses of 2.4 MPa radial and 1.7 MPa axial were applied to the sample. Sinusoidal stress oscillations were applied to the sample at 1 to 40 Hz over a range of RMS stress amplitude from 37 to 275 kPa. Dynamic stress/strain was measured before and after the core was saturated with deionized water. The slope of the linear portion of each stress/strain hysteresis loop was used to estimate Young's modulus as a function of frequency and amplitude for both the dry and wet sample. The modulus was observed to increase after the dry sample was saturated. For both dry and wet cases, the modulus decreased with increasing dynamic RMS stress amplitude at a constant frequency of 23 Hz. At constant RMS stress amplitude, the modulus increased with increasing frequency for the wet sample but remained constant for the dry sample. The observed nonlinear behavior of Young's modulus

  13. An Investigation of Ferrite and Nanocrystalline Core Materials for Medium-Frequency Power Transformers

    NASA Astrophysics Data System (ADS)

    Balci, Selami; Sefa, Ibrahim; Altin, Necmi

    2016-08-01

    In this study, two transformers are designed using the ferrite N87 and the nanocrystalline core materials for the same power level and operating frequency. The operating frequency is defined as 10 kHz, which is suitable for both materials. Modeling and simulation studies have been performed with the same finite element analysis software and the obtained results have been reported. The nanocrystalline and the ferrite N87 core materials have been compared according to both electrical and mechanical parameters. In these comparisons, many features such as core and winding losses, flux distributions, leakage flux, efficiency, and both electrical and mechanical performance have been reported comparatively in the case of rectangular waveform excitation of the transformer. Obtained results show that the weight and the volume of the transformer are reduced and more compact transformer is designed by using the nanocrystalline core material. In addition, besides the core loss, winding losses are also reduced in this design.

  14. Comparison of medium frequency pulsed radar interferometer and correlation analysis winds, part 1

    NASA Technical Reports Server (NTRS)

    Meek, C. E.; Reid, I. M.; Manson, A. H.

    1986-01-01

    In principle, the interferometer analysis determines the radial velocity and direction of single scatterers provided that each has a sufficiently different Doppler frequency to permit separation by spectral analysis. In fact, scatterers will not have constant radial velocity, and their Doppler frequencies as well as their directions will be modulated by their horizontal motion. Thus, there is a tradeoff between the poorer resolution but less smeared scatterers on shorter records and the higher resolution (longer) records. Three or more non-collinear scatterers are sufficient to determine the wind. It appears that the velocity found from the combined interferometer peaks agrees well with the apparent velocity from correlation methods, but the true velocity is a factor of 2 smaller. This difference might be resolved by searching for scatters showing regular movement between adjacent records.

  15. [Research on Time-frequency Characteristics of Magneto-acoustic Signal of Different Thickness Medium Based on Wave Summing Method].

    PubMed

    Zhang, Shunqi; Yin, Tao; Ma, Ren; Liu, Zhipeng

    2015-08-01

    Functional imaging method of biological electrical characteristics based on magneto-acoustic effect gives valuable information of tissue in early tumor diagnosis, therein time and frequency characteristics analysis of magneto-acoustic signal is important in image reconstruction. This paper proposes wave summing method based on Green function solution for acoustic source of magneto-acoustic effect. Simulations and analysis under quasi 1D transmission condition are carried out to time and frequency characteristics of magneto-acoustic signal of models with different thickness. Simulation results of magneto-acoustic signal were verified through experiments. Results of the simulation with different thickness showed that time-frequency characteristics of magneto-acoustic signal reflected thickness of sample. Thin sample, which is less than one wavelength of pulse, and thick sample, which is larger than one wavelength, showed different summed waveform and frequency characteristics, due to difference of summing thickness. Experimental results verified theoretical analysis and simulation results. This research has laid a foundation for acoustic source and conductivity reconstruction to the medium with different thickness in magneto-acoustic imaging.

  16. Transitions between various diffuse discharge modes in atmospheric-pressure helium in the medium-frequency range

    NASA Astrophysics Data System (ADS)

    Boisvert, J.-S.; Margot, J.; Massines, F.

    2016-08-01

    In this paper, we investigate DBDs in the medium frequency range (MF, 0.3-3 MHz). More precisely, for a 2 inter-dielectric gap in helium at atmospheric pressure, the frequency is varied from 1.0 to 2.7 MHz. The generated discharge shows similarities with both the low-frequency atmospheric-pressure glow discharge (APGD) and the atmospheric pressure capacitively coupled radio-frequency (CCRF) discharge. In the frequency range under investigation, two diffuse discharge modes can be observed depending on the voltage applied between the electrodes. At low applied voltage, the discharge emissions are barely visible and are concentrated in the center of the gas gap similarly to CCRF discharges in the Ω mode where the electron density is concentrated in the bulk. Ohmic heating is the main power transfer mechanism. At higher applied voltage, the discharge emissions are 10 times more intense and are closer to the dielectric surfaces similarly to the more common radio-frequency α mode. These two discharge modes can be observed in the same experimental conditions with the amplitude of the applied voltage as sole control parameter. The gas temperature obtained from N2 impurities rotational spectrum increases from room temperature to about 500 K while the power density rises from 10-1 to 101 W cm-3 when the applied voltage is increased. In addition, when the discharge transits back and forth from the Ω to the α mode, a hysteresis is observed. The transition from the Ω to the α mode occurs abruptly with a large RMS current increase while the transition from the α to the Ω mode is rather smooth with no significant discontinuity in the RMS current.

  17. Transitions between various diffuse discharge modes in atmospheric-pressure helium in the medium-frequency range

    NASA Astrophysics Data System (ADS)

    Boisvert, J.-S.; Margot, J.; Massines, F.

    2016-08-01

    In this paper, we investigate DBDs in the medium frequency range (MF, 0.3–3 MHz). More precisely, for a 2 inter-dielectric gap in helium at atmospheric pressure, the frequency is varied from 1.0 to 2.7 MHz. The generated discharge shows similarities with both the low-frequency atmospheric-pressure glow discharge (APGD) and the atmospheric pressure capacitively coupled radio-frequency (CCRF) discharge. In the frequency range under investigation, two diffuse discharge modes can be observed depending on the voltage applied between the electrodes. At low applied voltage, the discharge emissions are barely visible and are concentrated in the center of the gas gap similarly to CCRF discharges in the Ω mode where the electron density is concentrated in the bulk. Ohmic heating is the main power transfer mechanism. At higher applied voltage, the discharge emissions are 10 times more intense and are closer to the dielectric surfaces similarly to the more common radio-frequency α mode. These two discharge modes can be observed in the same experimental conditions with the amplitude of the applied voltage as sole control parameter. The gas temperature obtained from N2 impurities rotational spectrum increases from room temperature to about 500 K while the power density rises from 10‑1 to 101 W cm‑3 when the applied voltage is increased. In addition, when the discharge transits back and forth from the Ω to the α mode, a hysteresis is observed. The transition from the Ω to the α mode occurs abruptly with a large RMS current increase while the transition from the α to the Ω mode is rather smooth with no significant discontinuity in the RMS current.

  18. Medium-frequency impulsive-thrust-excited slosh waves during propellant reorientation with a geyser

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Shyu, K. L.; Lee, C. C.

    1992-01-01

    Slosh wave excitation induced by a resettling flowfield activated by 1.0-Hz impulsive thrust during the course of liquid reorientation with the initiation of geyser for liquid-fill levels of 30, 50, 65, 70, and 80 percent has been studied. Characteristics of slosh waves of various frequencies excited by the resettling flowfield are discussed. Slosh wave excitations shift the fluid mass distribution in the container which imposes time-dependent variations in spacecraft moment of inertia. This information is important for spacecraft control during the course of liquid reorientation.

  19. Case-control study of allele frequencies of 15 short tandem repeat loci in males with impulsive violent behavior

    PubMed Central

    Yang, Chun; Ba, Huajie; Gao, Zhiqin; Zhao, Hanqing; Yu, Haiying; Guo, Wei

    2013-01-01

    Background Analysis of genetic polymorphisms in short tandem repeats (STRs) is an accepted method for detecting associations between genotype and phenotype but it has not previously been used in the study of the genetics of impulsive violent behavior. Objective Compare the prevalence of different polymorphisms in 15 STR loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA) between men with a history of impulsive violence and male control subjects without a history of impulsive violence. Methods The distributions of the alleles of the 15 STR loci were compared between 407 cases with impulsive violent behavior and 415 controls using AmpFlSTR® Identifiler™ kits. Results Compared to controls, the average frequencies of the following alleles were significantly lower in individuals with a history of violent behavior: allele 10 of TH01 (OR=0.29, 95%CI=0.16-0.52, p<0.0001,), allele 8 of TPOX (OR=0.71, 95%CI=0.58-0.86, p=0.0005), allele 9 of TPOX (OR=0.65, 95%CI=0.47-0.89, p=0.0072) and allele 14 of CSF1PO (OR=0.27, 95%CI=0.11-0.68, p=0.0035). One allele was significantly higher in cases than controls: allele 11 of TPOX (OR=1.79, 95%CI=1.45-2.22, p<0.0001). Conclusions To the best of our knowledge, this is the first behavioral genetic study that clearly demonstrates a close relationship between specific genetic markers and impulsive aggression in non-psychiatric offenders. Further prospective work will be needed to determine whether or not the alleles identified can be considered risk factors for impulsive aggression and, if so, the underlying mechanisms that result in this relationship. PMID:24991178

  20. Digital audio broadcasting: Measuring techniques and coverage performance for a medium power VHF single frequency network

    NASA Astrophysics Data System (ADS)

    Maddocks, M. C. D.; Eng, C.; Pullen, I. R.; Green, J. A.

    1995-02-01

    The advent of digital formats such as CD has created demand for uniformly high audio quality from radio. In order to provide such high-quality stereo reception, a Digital Audio Broadcasting (DAB) system capable of reliable reception in vehicles and on portables has been developed by the European EUREKA 147 Project. As a VHF frequency allocation would appear most suitable for the introduction of terrestrial broadcasting of DAB in the United Kingdom, the BBC is undertaking a major experiment to test the EUREKA DAB system and to generate data to allow efficient planning of its transmitter network. A network of four, 1 kW e.r.p., VHF transmitters has been installed to cover the London area in England. This Report describes the experimental program and the rationale and measurement techniques behind it. The results show a wide-area coverage from the transmitter network which is in reasonable agreement with computer predictions. This indicates that the current transmitting and receiving equipment (built to the EUREKA specification) is operating in the way that would be expected from theoretical studies and simulation. The results also provide quantitative values which can be used for coverage prediction and for international co-ordination of services. Finally, the performance of the system demonstrates a number of the benefits of the EUREKA DAB system for mobile and portable reception.

  1. Low-frequency wiggler modes in the free-electron laser with a dusty magnetoplasma medium

    NASA Astrophysics Data System (ADS)

    Jafari, S.

    2015-07-01

    An advanced incremental scheme for generating tunable coherent radiation in a free-electron laser has been presented: the basic concept is the use of a relativistic electron beam propagating through a magnetized dusty plasma channel where dust helicon, dust Alfven and coupled dust cyclotron-Alfven waves can play a role as a low-frequency wiggler, triggering coherent emissions. The wiggler wavelength at the sub-mm level allows one to reach the wavelength range from a few nm down to a few Å with moderately relativistic electrons of kinetic energies of a few tens/hundreds of MeV. The laser gain and the effects of beam self-electric and self-magnetic fields on the gain have been estimated and compared with findings of the helical magnetic and electromagnetic wigglers in vacuum. To study the chaotic regions of the electron motion in the dusty plasma wave wiggler, a time independent Hamiltonian has been obtained. The Poincare surface of a section map has been used numerically to analyze the nonintegrable system where chaotic regions in phase-space emerge. This concept opens a path toward a new generation of synchrotron sources based on compact plasma structures.

  2. Detection of traveling ionospheric disturbances by medium-frequency Doppler sounding using AM radio transmissions

    NASA Astrophysics Data System (ADS)

    Chilcote, M.; LaBelle, J.; Lind, F. D.; Coster, A. J.; Miller, E. S.; Galkin, I. A.; Weatherwax, A. T.

    2015-03-01

    Nighttime traveling ionosphere disturbances (TIDs) propagating in the lower F region of the ionosphere have been detected by measuring time variations in the Doppler shifts of commercial AM radio broadcast signals. Three receivers, components of the Intercepted Signals for Ionospheric Science (ISIS) Array software radio instrumentation network in the northeastern United States, recorded signals from two radio stations during 11 nights in March-April, 2012. By combining these measurements, TIDs were detected as approximately 40min periodic variations in the frequencies of the received signals resulting from Doppler shifts produced by the ionosphere. The variations had amplitudes of up to a few tenths of a hertz and were correlated across the array. For one study interval, 0000-0400 UT on 13 April 2012, simultaneous GPS total electron content, Digisonde®, and Super Dual-Auroral Radar Network coherent backscatter radar measurements confirmed the detection of TIDs with the same characteristics. Besides TIDs, the receiver network often detected large (nearly 1 Hz) upward (downward) Doppler shifts of the AM broadcast signals at the dawn (dusk) terminator. These results demonstrate that AM radio signals can be used for detection and monitoring of nighttime TIDs and related effects.

  3. Three RFLPs defining a haplotype associated with the common mutation in a human medium-chain acyl-CoA dehydrogenase (MCAD) deficiency occur in Alu repeats

    SciTech Connect

    Zhifang Zhang; Yeqing Zhou; Kelly, D.P.; Strauss, A.W. St. Louis Children's Hospital, MO ); Kolvraa, S.; Gregersen, N. )

    1993-06-01

    Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is a common inborn error of fatty-acid oxidation and may cause sudden infant death. Previous studies revealed that (i) homozygosity for an A-to-G mutation at nucleotide 985 of the mRNA coding region (A985G) is an extremely common cause of MCAD deficiency and (ii) MCAD deficiency is strongly associated with a particular haplotype for RFLPs for BanII, PstI, and TaqI. TaqI allele 2 is always associated with the A985G mutation in human MCAD deficiency. In this study, the authors have delineated the molecular basis of the RFLPs for PstI, BamHI, and TaqI in the human MCAD gene. Their results prove that the three RFLPs are caused by point mutations in the 8 kb of DNA encompassing exons 8--10 of the human MCAD gene. The TaqI polymorphism is caused by a C-to-A substitution 392 bp upstream of the exon 8, and the PstI and BamHI polymorphisms are due to T-to-C and G-to-A substitutions, respectively, which are 727 and 931 bp downstream of exon 10, respectively. All three RFLPs lie within Alu repetitive sequences. Comparison of intronic sequences immediately following exon 10 from two normal individuals with different haplotypes showed that this region contains densely packed Alu repeats and is highly polymorphic. The results are consistent both with a founder effect as the cause of the high prevalence of a single (A985G) mutation in MCAD deficiency and with its association with a particular haplotype for these intragenic RFLPs. 27 refs., 6 figs., 1 tab.

  4. Multi-frequency based location search algorithm of small electromagnetic inhomogeneities embedded in two-layered medium

    NASA Astrophysics Data System (ADS)

    Park, Won-Kwang; Park, Taehoon

    2013-07-01

    In this paper, we consider a problem for finding the locations of electromagnetic inhomogeneities completely embedded in homogeneous two layered medium. For this purpose, we present a filter function operated at several frequencies and design an algorithm for finding the locations of such inhomogeneities. It is based on the fact that, the collected Multi-Static Response (MSR) matrix can be modeled via a rigorous asymptotic expansion formula of the scattering amplitude due to the presence of such inhomogeneities. In order to show the effectiveness, we compare the proposed algorithm with traditional MUltiple SIgnal Classification (MUSIC) algorithm and Kirchhoff migration. Various numerical results demonstrate that the proposed algorithm is robust with respect to random noise and yields more accurate location than the MUSIC algorithm and Kirchhoff migration.

  5. The effects of sampling frequency on the climate statistics of the European Centre for Medium-Range Weather Forecasts

    SciTech Connect

    Phillips, T.J.; Gates, W.L. ); Arpe, K. )

    1992-12-20

    The effects of sampling frequency on the first- and second-moment statistics of selected European Centre for Medium-Range Weather Forecasts (ECMWF) model variables are investigated in a simulation of perpetual July' with a diurnal cycle included and with surface and atmospheric fields saved at hourly intervals. The shortest characteristic time scales are those of ground heat fluxes and temperatures, precipitation and runoff, convective processes, cloud properties, and atmospheric vertical motion, while the longest time scales are exhibited by soil temperature and moisture, surface pressure, and atmospheric specific humidity, temperature, and wind. The time scales of surface heat and momentum fluxes and of convective processes are substantially shorter over land than over oceans. An appropriate sampling frequency for each model variable is obtained by comparing the estimates of first- and second-moment statistics determined at intervals ranging from 2 to 24 hours with the best' estimates obtained from hourly sampling. Relatively accurate estimation of first- and second-moment climate statistics can be achieved by sampling a model variable at intervals that usually are longer than the bandwidth of its time series but that often are shorter than its characteristic time scale. The superior estimates of first-moment statistics are accompanied by inferior estimates of the variance of the daily means due to the presence of systematic biases, but these probably can be avoided by defining a different measure of low-frequency variability. Estimates of the intradiurnal variance of accumulated precipitation and surface runoff also are strongly impacted by the length of the storage interval. In light of these results, several alternative strategies for storage of the EMWF model variables are recommended. 20 refs., 9 figs., 1 tab.

  6. The effects of sampling frequency on the climate statistics of the European Centre for Medium-Range Weather Forecasts

    NASA Astrophysics Data System (ADS)

    Phillips, Thomas J.; Gates, W. Lawrence; Arpe, Klaus

    1992-12-01

    The effects of sampling frequency on the first- and second-moment statistics of selected European Centre for Medium-Range Weather Forecasts (ECMWF) model variables are investigated in a simulation of "perpetual July" with a diurnal cycle included and with surface and atmospheric fields saved at hourly intervals. The shortest characteristic time scales (as determined by the e-folding time of lagged autocorrelation functions) are those of ground heat fluxes and temperatures, precipitation and runoff, convective processes, cloud properties, and atmospheric vertical motion, while the longest time scales are exhibited by soil temperature and moisture, surface pressure, and atmospheric specific humidity, temperature, and wind. The time scales of surface heat and momentum fluxes and of convective processes are substantially shorter over land than over oceans. An appropriate sampling frequency for each model variable is obtained by comparing the estimates of first- and second-moment statistics determined at intervals ranging from 2 to 24 hours with the "best" estimates obtained from hourly sampling. Relatively accurate estimation of first- and second-moment climate statistics (10% errors in means, 20% errors in variances) can be achieved by sampling a model variable at intervals that usually are longer than the bandwidth of its time series but that often are shorter than its characteristic time scale. For the surface variables, sampling at intervals that are nonintegral divisors of a 24-hour day yields relatively more accurate time-mean statistics because of a reduction in errors associated with aliasing of the diurnal cycle and higher-frequency harmonics. The superior estimates of first-moment statistics are accompanied by inferior estimates of the variance of the daily means due to the presence of systematic biases, but these probably can be avoided by defining a different measure of low-frequency variability. Estimates of the intradiurnal variance of accumulated

  7. Rich Medium Composition Affects Escherichia coli Survival, Glycation, and Mutation Frequency during Long-Term Batch Culture

    PubMed Central

    Kram, Karin E.

    2015-01-01

    Bacteria such as Escherichia coli are frequently grown to high density to produce biomolecules for study in the laboratory. To achieve this, cells can be incubated in extremely rich media that increase overall cell yield. In these various media, bacteria may have different metabolic profiles, leading to changes in the amounts of toxic metabolites produced. We have previously shown that stresses experienced during short-term growth can affect the survival of cells during the long-term stationary phase (LTSP). Here, we incubated cells in LB, 2× yeast extract-tryptone (YT), Terrific Broth, or Super Broth medium and monitored survival during the LTSP, as well as other reporters of genetic and physiological change. We observe differential cell yield and survival in all media studied. We propose that differences in long-term survival are the result of changes in the metabolism of components of the media that may lead to increased levels of protein and/or DNA damage. We also show that culture pH and levels of protein glycation, a covalent modification that causes protein damage, affect long-term survival. Further, we measured mutation frequency after overnight incubation and observed a correlation between high mutation frequencies at the end of the log phase and loss of viability after 4 days of LTSP incubation, indicating that mutation frequency is potentially predictive of long-term survival. Since glycation and mutation can be caused by oxidative stress, we measured expression of the oxyR oxidative stress regulator during log-phase growth and found that higher levels of oxyR expression during the log phase are consistent with high mutation frequency and lower cell density during the LTSP. Since these complex rich media are often used when producing large quantities of biomolecules in the laboratory, the observed increase in damage resulting in glycation or mutation may lead to production of a heterogeneous population of plasmids or proteins, which could affect the

  8. Additive effect of repeated bouts of individualized frequency whole body vibration on postural stability in young adults.

    PubMed

    Dickin, D Clark; Heath, Jacqueline E

    2014-08-01

    Whole body vibration (WBV) has been shown to improve force and power output as well as flexibility and speed, with improvements suggested to result from reduced electromechanical delays, improved rate of force development, and sensitivity of muscle spindles. Fixed frequency studies on postural control have been somewhat equivocal; however, individualized frequency protocols have shown promising results in other motor tasks. To assess this, 18 healthy young adults experienced three 4-minute WBV sessions with postural control assessed before vibration, after multiple exposures, and during recovery, with altered levels of sensory information available to the participants. Sway velocity, sway path length, and sway area were assessed in each environment. Study findings revealed that stability was impacted following WBV, with more challenging environments eliciting improvements persisting for 20 minutes. When the environment was less challenging, postural stability was impaired; however, the effects dissipated quickly (10-20 min). It was determined that exposure to individualized frequency WBV served to impair postural control when the challenge was low, but resulted in heightened stability when the overall challenge was high and vestibular information was needed for stability.

  9. Energy-density field approach for low- and medium-frequency vibroacoustic analysis of complex structures using a statistical computational model

    NASA Astrophysics Data System (ADS)

    Kassem, M.; Soize, C.; Gagliardini, L.

    2009-06-01

    In this paper, an energy-density field approach applied to the vibroacoustic analysis of complex industrial structures in the low- and medium-frequency ranges is presented. This approach uses a statistical computational model. The analyzed system consists of an automotive vehicle structure coupled with its internal acoustic cavity. The objective of this paper is to make use of the statistical properties of the frequency response functions of the vibroacoustic system observed from previous experimental and numerical work. The frequency response functions are expressed in terms of a dimensionless matrix which is estimated using the proposed energy approach. Using this dimensionless matrix, a simplified vibroacoustic model is proposed.

  10. Intraseasonal oscillations of the zonal wind near the mesopause observed with medium-frequency and meteor radars in the tropics

    NASA Astrophysics Data System (ADS)

    Isoda, Fusako; Tsuda, Toshitaka; Nakamura, Takuji; Vincent, R. A.; Reid, I. M.; Achmad, Effendy; Sadewo, Adi; Nuryanto, Agus

    2004-11-01

    We studied the behavior of intraseasonal oscillations (ISO) of the zonal wind velocity in the equatorial mesosphere and lower thermosphere (MLT) using simultaneous observations during 500 days from 1 January 1996 with a meteor radar at Jakarta (6°S, 107°E) and two medium-frequency radars at Pontianak (0°N, 109°E) and Christmas Island (2°N, 157°W). Cross-correlation analysis of the ISO at 88 km indicated that the phase difference of the ISO between Pontianak and Christmas Island is, on average, small in spite of the longitudinal difference of ˜90°. Therefore the ISO in the equatorial MLT region seems to be a variation of zonal mean flow. At Jakarta the amplitude of the ISO of the zonal wind at 88 km was somewhat smaller than that observed at the other two equatorial sites. The peak of the ISO amplitude appears at ˜88 km at both Pontianak and Christmas Island, but the peak seemed to be slightly lower at Jakarta. We also investigated long-term variation of the ISO of the zonal wind at 84 km using Jakarta meteor radar data observed from January 1993 to October 1999. Biennial variations are dominant in the ISO amplitude of the mesospheric zonal winds and the zonal amplitude variations of the diurnal tide. A relation between the ISO of the zonal wind and tidal amplitude is suggested. However, gravity wave activity in the MLT region did not correlate with the ISO in the zonal wind. We employed the outgoing longwave radiation (OLR) in the tropical troposphere as an index for excitation intensity of the atmospheric waves. The long-term variations of the ISO components in the OLR over the western Pacific were characterized by the tropospheric biennial oscillations, which seems to correlate with the ISO of the mean zonal winds and diurnal tides in the mesosphere.

  11. Measuring postural-related changes of spontaneous baroreflex sensitivity after repeated long-duration diving: frequency domain approaches.

    PubMed

    Faes, Luca; Masè, Michela; Nollo, Giandomenico; Chon, Ki H; Florian, John P

    2013-11-01

    Sustained water immersion is thought to modulate orthostatic tolerance to an extent dependent on the duration and repetition over consecutive days of the diving sessions. We tested this hypothesis investigating in ten healthy subjects the potential changes in the cardiovascular response to head-up tilt induced by single and multiple resting air dives. Parametric cross-spectral analysis of spontaneous RR interval and systolic arterial pressure variability was performed in three experimental sessions: before diving (BD), after single 6-hour dive (ASD), and after multiple 6-hour dives (AMD, 5 consecutive days with 18-hour surface interval). From this analysis, baroreflex sensitivity (BRS) was computed as spectral power ratio (αBRS), non-causal transfer function gain (tfBRS) and causal transfer function gain (γBRS) evaluated at low frequency (0.04-0.14Hz) in the supine position (su) as well as in the standing upright position in the early tilt (et) and late tilt (lt) epochs. We found that, while αBRS decreased significantly in et and lt compared to su during all sessions, tfBRS and γBRS decreased during ASD and AMD but not during BD; moreover γBRS evidenced a progressive decrease from BD to ASD and to AMD in both et and lt epochs. These results indicate the necessity of following a causal approach for the estimation of BRS in the frequency domain, and suggest a progressive impairment of the baroreflex response to postural stress after single and multiple dives, which may reflect symptoms of increasing orthostatic intolerance.

  12. Planck intermediate results. XVII. Emission of dust in the diffuse interstellar medium from the far-infrared to microwave frequencies

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Abergel, A.; Ade, P. A. R.; Aghanim, N.; Alves, M. I. R.; Aniano, G.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Battaner, E.; Benabed, K.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bonaldi, A.; Bond, J. R.; Bouchet, F. R.; Boulanger, F.; Burigana, C.; Cardoso, J.-F.; Catalano, A.; Chamballu, A.; Chiang, H. C.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Couchot, F.; Crill, B. P.; Cuttaia, F.; Danese, L.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Ghosh, T.; Giard, M.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gregorio, A.; Gruppuso, A.; Guillet, V.; Hansen, F. K.; Harrison, D.; Helou, G.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Jaffe, A. H.; Jaffe, T. R.; Joncas, G.; Jones, A.; Jones, W. C.; Juvela, M.; Kalberla, P.; Keihänen, E.; Kerp, J.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lawrence, C. R.; Leonardi, R.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maino, D.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Mazzotta, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C. A.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Pratt, G. W.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reach, W. T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rusholme, B.; Sandri, M.; Savini, G.; Spencer, L. D.; Starck, J.-L.; Sureau, F.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Verstraete, L.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Winkel, B.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-06-01

    The dust-Hi correlation is used to characterize the emission properties of dust in the diffuse interstellar medium (ISM) from far infrared wavelengths to microwave frequencies. The field of this investigation encompasses the part of the southern sky best suited to study the cosmic infrared and microwave backgrounds. We cross-correlate sky maps from Planck, the Wilkinson Microwave Anisotropy Probe (WMAP), and the diffuse infrared background experiment (DIRBE), at 17 frequencies from 23 to 3000 GHz, with the Parkes survey of the 21 cm line emission of neutral atomic hydrogen, over a contiguous area of 7500 deg2 centred on the southern Galactic pole. We present a general methodology to study the dust-Hi correlation over the sky, including simulations to quantify uncertainties. Our analysis yields four specific results. (1) We map the temperature, submillimetre emissivity, and opacity of the dust per H-atom. The dust temperature is observed to be anti-correlated with the dust emissivity and opacity. We interpret this result as evidence of dust evolution within the diffuse ISM. The mean dust opacity is measured to be (7.1 ± 0.6) × 10-27 cm2 H-1 × (ν/ 353 GHz)1.53 ± 0.03 for 100 ≤ ν ≤ 353 GHz. This is a reference value to estimate hydrogen column densities from dust emission at submillimetre and millimetre wavelengths. (2) We map the spectral index βmm of dust emission at millimetre wavelengths (defined here as ν ≤ 353 GHz), and find it to be remarkably constant at βmm = 1.51 ± 0.13. We compare it with the far infrared spectral index βFIR derived from greybody fits at higher frequencies, and find a systematic difference, βmm - βFIR = - 0.15, which suggests that the dust spectral energy distribution (SED) flattens at ν ≤ 353 GHz. (3) We present spectral fits of the microwave emission correlated with Hi from 23 to 353 GHz, which separate dust and anomalous microwave emission (AME). We show that the flattening of the dust SED can be accounted for with

  13. Haplotype frequencies of 17 Y-chromosomal short tandem repeat loci from the Cukurova region of Turkey

    PubMed Central

    Serin, Ayse; Canan, Husniye; Alper, Behnan; Sertdemir, Yasar

    2011-01-01

    Aim To investigate the distribution of 17 Y-short tandem repeat (STR) loci in the population of the Cukurova region of Turkey. Methods In the period between 2009 and 2010, we investigated the distribution of 17 Y-STRs in a sample of 249 unrelated healthy men from the Cukurova region of Turkey. Genomic DNA was extracted with InstaGene matrix and Y-STRs were determined using the AmpFISTR Yfiler PCR amplification kit. Gene and haplotype diversity values were estimated using the Arlequin software. To compare our data to other populations, population pairwise genetic distances and associated probability values were calculated using the Y Chromosome Haplotype Reference Database Web site software. Results At 17 Y-STR loci we detected 148 alleles. The lowest gene diversity in this region was 0.51 for DYS391 and the highest 0.95 for DYS385a/b. Haplotype diversity was 0.9997 ± 0.0004. We compared our data with haplotype data of other Turkish populations and no significant differences were found, except with Ankara population (Φst = 0.025, P = 0.018). Comparisons were also made with the neighboring populations using analysis of molecular variance of the Y-STR loci genetic structure and our population was nearest to Lenkoran-Azerbaijani (Φst = 0.012, P = 0.068) and Iranian Ahvaz population (Φst = 0.007, P = 0.173), followed by Greek (Φst = 0.026, P = 0.000) and Russian (Φst = 0.048, P = 0.000) population. Other countries like Portugal, Spain, Italy, Egypt, Israel (Palestinian Authority Area), and Taiwan showed a high genetic distance from our population. Conclusion Our study showed that Y-STR polymorphisms were a powerful discrimination tool for routine forensic applications and could be used in genealogical investigations. PMID:22180269

  14. Recommendations of the DNA Commission of the International Society for Forensic Genetics (ISFG) on quality control of autosomal Short Tandem Repeat allele frequency databasing (STRidER).

    PubMed

    Bodner, Martin; Bastisch, Ingo; Butler, John M; Fimmers, Rolf; Gill, Peter; Gusmão, Leonor; Morling, Niels; Phillips, Christopher; Prinz, Mechthild; Schneider, Peter M; Parson, Walther

    2016-09-01

    The statistical evaluation of autosomal Short Tandem Repeat (STR) genotypes is based on allele frequencies. These are empirically determined from sets of randomly selected human samples, compiled into STR databases that have been established in the course of population genetic studies. There is currently no agreed procedure of performing quality control of STR allele frequency databases, and the reliability and accuracy of the data are largely based on the responsibility of the individual contributing research groups. It has been demonstrated with databases of haploid markers (EMPOP for mitochondrial mtDNA, and YHRD for Y-chromosomal loci) that centralized quality control and data curation is essential to minimize error. The concepts employed for quality control involve software-aided likelihood-of-genotype, phylogenetic, and population genetic checks that allow the researchers to compare novel data to established datasets and, thus, maintain the high quality required in forensic genetics. Here, we present STRidER (http://strider.online), a publicly available, centrally curated online allele frequency database and quality control platform for autosomal STRs. STRidER expands on the previously established ENFSI DNA WG STRbASE and applies standard concepts established for haploid and autosomal markers as well as novel tools to reduce error and increase the quality of autosomal STR data. The platform constitutes a significant improvement and innovation for the scientific community, offering autosomal STR data quality control and reliable STR genotype estimates. PMID:27352221

  15. Variable Frequency of Plastid RNA Editing among Ferns and Repeated Loss of Uridine-to-Cytidine Editing from Vascular Plants

    PubMed Central

    Guo, Wenhu; Grewe, Felix; Mower, Jeffrey P.

    2015-01-01

    The distinct distribution and abundance of C-to-U and U-to-C RNA editing among land plants suggest that these two processes originated and evolve independently, but the paucity of information from several key lineages limits our understanding of their evolution. To examine the evolutionary diversity of RNA editing among ferns, we sequenced the plastid transcriptomes from two early diverging species, Ophioglossum californicum and Psilotum nudum. Using a relaxed automated approach to minimize false negatives combined with manual inspection to eliminate false positives, we identified 297 C-to-U and three U-to-C edit sites in the O. californicum plastid transcriptome but only 27 C-to-U and no U-to-C edit sites in the P. nudum plastid transcriptome. A broader comparison of editing content with the leptosporangiate fern Adiantum capillus-veneris and the hornwort Anthoceros formosae uncovered large variance in the abundance of plastid editing, indicating that the frequency and type of RNA editing is highly labile in ferns. Edit sites that increase protein conservation among species are more abundant and more efficiently edited than silent and non-conservative sites, suggesting that selection maintains functionally important editing. The absence of U-to-C editing from P. nudum plastid transcripts and other vascular plants demonstrates that U-to-C editing loss is a recurrent phenomenon in vascular plant evolution. PMID:25568947

  16. Variable frequency of plastid RNA editing among ferns and repeated loss of uridine-to-cytidine editing from vascular plants.

    PubMed

    Guo, Wenhu; Grewe, Felix; Mower, Jeffrey P

    2015-01-01

    The distinct distribution and abundance of C-to-U and U-to-C RNA editing among land plants suggest that these two processes originated and evolve independently, but the paucity of information from several key lineages limits our understanding of their evolution. To examine the evolutionary diversity of RNA editing among ferns, we sequenced the plastid transcriptomes from two early diverging species, Ophioglossum californicum and Psilotum nudum. Using a relaxed automated approach to minimize false negatives combined with manual inspection to eliminate false positives, we identified 297 C-to-U and three U-to-C edit sites in the O. californicum plastid transcriptome but only 27 C-to-U and no U-to-C edit sites in the P. nudum plastid transcriptome. A broader comparison of editing content with the leptosporangiate fern Adiantum capillus-veneris and the hornwort Anthoceros formosae uncovered large variance in the abundance of plastid editing, indicating that the frequency and type of RNA editing is highly labile in ferns. Edit sites that increase protein conservation among species are more abundant and more efficiently edited than silent and non-conservative sites, suggesting that selection maintains functionally important editing. The absence of U-to-C editing from P. nudum plastid transcripts and other vascular plants demonstrates that U-to-C editing loss is a recurrent phenomenon in vascular plant evolution.

  17. Frequency of the C9orf72 hexanucleotide repeat expansion in patients with amyotrophic lateral sclerosis and frontotemporal dementia: a cross-sectional study

    PubMed Central

    Majounie, Elisa; Renton, Alan E; Mok, Kin; Dopper, Elise GP; Waite, Adrian; Rollinson, Sara; Chiò, Adriano; Restagno, Gabriella; Nicolaou, Nayia; Simon-Sanchez, Javier; van Swieten, John C; Abramzon, Yevgeniya; Johnson, Janel O; Sendtner, Michael; Pamphlett, Roger; Orrell, Richard W; Mead, Simon; Sidle, Katie C; Houlden, Henry; Rohrer, Jonathan D; Morrison, Karen E; Pall, Hardev; Talbot, Kevin; Ansorge, Olaf; Hernandez, Dena G; Arepalli, Sampath; Sabatelli, Mario; Mora, Gabriele; Corbo, Massimo; Giannini, Fabio; Calvo, Andrea; Englund, Elisabet; Borghero, Giuseppe; Floris, Gian Luca; Remes, Anne M; Laaksovirta, Hannu; McCluskey, Leo; Trojanowski, John Q; Van Deerlin, Vivianna M; Schellenberg, Gerard D; Nalls, Michael A; Drory, Vivian E; Lu, Chin-Song; Yeh, Tu-Hsueh; Ishiura, Hiroyuki; Takahashi, Yuji; Tsuji, Shoji; Le Ber, Isabelle; Brice, Alexis; Drepper, Carsten; Williams, Nigel; Kirby, Janine; Shaw, Pamela; Hardy, John; Tienari, Pentti J; Heutink, Peter; Morris, Huw R; Pickering-Brown, Stuart; Traynor, Bryan J

    2012-01-01

    Summary Background We aimed to accurately estimate the frequency of a hexanucleotide repeat expansion in C9orf72 that has been associated with a large proportion of cases of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Methods We screened 4448 patients diagnosed with ALS (El Escorial criteria) and 1425 patients with FTD (Lund-Manchester criteria) from 17 regions worldwide for the GGGGCC hexanucleotide expansion using a repeat-primed PCR assay. We assessed familial disease status on the basis of self-reported family history of similar neurodegenerative diseases at the time of sample collection. We compared haplotype data for 262 patients carrying the expansion with the known Finnish founder risk haplotype across the chromosomal locus. We calculated age-related penetrance using the Kaplan-Meier method with data for 603 individuals with the expansion. Findings In patients with sporadic ALS, we identified the repeat expansion in 236 (7·0%) of 3377 white individuals from the USA, Europe, and Australia, two (4·1%) of 49 black individuals from the USA, and six (8·3%) of 72 Hispanic individuals from the USA. The mutation was present in 217 (39·3%) of 552 white individuals with familial ALS from Europe and the USA. 59 (6·0%) of 981 white Europeans with sporadic FTD had the mutation, as did 99 (24·8%) of 400 white Europeans with familial FTD. Data for other ethnic groups were sparse, but we identified one Asian patient with familial ALS (from 20 assessed) and two with familial FTD (from three assessed) who carried the mutation. The mutation was not carried by the three Native Americans or 360 patients from Asia or the Pacific Islands with sporadic ALS who were tested, or by 41 Asian patients with sporadic FTD. All patients with the repeat expansion had (partly or fully) the founder haplotype, suggesting a one-off expansion occurring about 1500 years ago. The pathogenic expansion was non-penetrant in individuals younger than 35 years, 50

  18. Signature of 3-4 day planetary waves in the equatorial ionospheric F layer height and medium frequency radar winds over Tirunelveli (8.7oN)

    NASA Astrophysics Data System (ADS)

    Sundararaman, Sathishkumar

    Signature of 3-4 day planetary waves in the equatorial ionospheric F layer height and medium frequency radar winds over Tirunelveli (8.7oN) S. Sathishkumar1, R. Dhanya1, K. Emperumal1, D. Tiwari2, S. Gurubaran1 and A. Bhattacharyya2 1. Equatorial Geophysical Research Laboratory, Indian Institute of Geomagnetism, Tirunelveli, India 2. Indian Institute of Geomagnetism, Navi Mumbai, India Email: sathishmaths@gmail.com Abstract The equatorial atmosphere-ionosphere system has been studied theoretically and observationally in the past. In the equatorial atmosphere, oscillations with periods of 3-4 days are often observed in the medium frequency (MF) radar over Tirunelveli (8.7oN, 77.8oE, 1.34oN geomag. lat.). Earlier observations show the clear evidence that these waves can propagate from the stratosphere to ionosphere. A digital ionosonde has been providing useful information on several ionospheric parameters from the same site. Simultaneous observations of mesospheric winds using medium frequency radar and F-layer height (h'F) from ionosonde reveal that the 3-4 day wave was evident in both the component during the 01 June 2007 and 31 July 2007. The 3-4 day wave could have an important role in the day to day variability of the equatorial ionosphere evening uplift. Results from an extensive analysis that is being carried out in the direction of 3-4 day wave present in the ionosphere will be presented.

  19. [Sugar beet (Beta vulgaris L.) morphogenesis in vitro: effects of phytohormone type and concentration in the culture medium, type of explants, and plant genotype on shoot regeneration frequency].

    PubMed

    Mishutkina, Ia V; Gaponenko, A K

    2006-02-01

    In vitro regeneration techniques have been optimized for seven strains and cultivars of sugar beet (Beta vulgaris L.) bred in Russia. The frequency of shoot regeneration from somatic cells and tissues of sugar beet varies from 10 to 97% depending on the explant type, culture-medium composition, and genotype. The in vitro regeneration potential has been estimated in plants with different genotypes. The effect of medium composition (phytohormones and carbohydrates) on the frequency of the formation of a morphogenic callus competent for plant regeneration has been determined. The effect of the types and concentrations of various cytokines (zeatin, kinetin, and 6-benzylaminopurine) on direct shoot regeneration from cotyledon nodes has been estimated. The culture-medium composition has been optimized for direct shoot regeneration from petioles. The effects of different concentrations of abscisic acid on the frequency of shoot regeneration from a morphogenic callus has been studied. Micropropagation has been used to obtain petiole explants and reproduce the shoots obtained by direct regeneration from cotyledon nodes, petioles, and calluses. Improved shoot-regeneration methods can be used for both agrobacterial and bioballistic genetic transformation of the sugar beet genotypes studied.

  20. The doppler frequency shift caused by the inhomogeneities of a medium induced by pulses of intense laser radiation

    NASA Astrophysics Data System (ADS)

    Rozanov, N. N.; Kiselev, Al. S.; Kiselev, An. S.

    2008-08-01

    Self-reflection of pulses of intense laser radiation from an inhomogeneity induced by them in a medium with fast optical nonlinearity is analyzed. The reflected radiation is characterized by a considerable Doppler shift and by a signal magnitude that is sufficient for experimental detection.

  1. Numerical solution of Maxwell equations by a finite-difference time-domain method in a medium with frequency and spatial dispersion.

    PubMed

    Potravkin, N N; Perezhogin, I A; Makarov, V A

    2012-11-01

    We propose an alternative method of integration of Maxwell equations. This method is the generalization of a finite-difference time-domain method with an auxiliary differential equation for the case of a linear optical medium with a frequency dispersion and an arbitrary source of spatial dispersion. We apply this method to the problem of the propagation of short plane-wave linearly polarized light pulses in such a medium. It is shown that some features of their propagation are completely different from those that are generally recognized for the linear optical activity phenomenon. For example, in some cases an initially linearly polarized light pulse becomes elliptically polarized during the propagation. This effect is more prominent in the front part of the pulse. PMID:23214905

  2. Plasma channel produced by femtosecond laser pulses as a medium for amplifying electromagnetic radiation of the subterahertz frequency range

    SciTech Connect

    Bogatskaya, A V; Volkova, E A; Popov, A M

    2013-12-31

    The electron energy distribution function in the plasma channel produced by a femtosecond laser pulse with a wavelength of 248 nm in atmospheric-pressure gases was considered. Conditions were determined whereby this channel may be employed for amplifying electromagnetic waves up to the terahertz frequency range over the energy spectrum relaxation time ∼10{sup -7} s. Gains were calculated as functions of time and radiation frequency. The effect of electron – electron collisions on the rate of relaxation processes in the plasma and on its ability to amplify the electromagnetic radiation was investigated. (interaction of laser radiation with matter)

  3. Frequency Fine Structures of Type III Bursts Due to Localized Medium-Scale Density Structures Along Paths of Type III Beams

    NASA Astrophysics Data System (ADS)

    Li, B.; Cairns, Iver H.; Robinson, P. A.

    2012-07-01

    Predictions from large-scale kinetic simulations are presented for the effects on coronal type III bursts of localized, medium-scale, enhanced density structures superposed on the coronal background along the paths of type III beams. The simulations show that these density structures can produce pronounced frequency fine structures in type III spectra. Flux intensifications and reductions of f p and 2 f p emission relative to those for the unperturbed background corona occur at frequencies corresponding to the density structures, where f p is the local electron plasma frequency. Frequency fine structures that are intense, slowly drifting, and narrowband, and thus resemble the characteristics of stria bursts, are predicted for the 2 f p emission. The 2 f p results are consistent with the qualitative proposal of Takakura and Yousef ( Solar Phys. 40, 421, 1975) for the interpretation of stria/type IIIb bursts. However, the predicted f p emission is much weaker than the 2 f p emission and generally below observable levels, and the predicted frequency fine structures do not always show stria characteristics. The predictions are thus inconsistent with the qualitative suggestion of Takakura and Yousef and the interpretations of many observers that stria bursts occur more often in f p than in 2 f p emission. The significant discrepancies for f p emission between our numerical calculations and the qualitative proposition of Takakura and Yousef (1975) are mainly caused by: i) differences in the detailed emission processes, ii) neglect of scattering of f p emission off small-scale density fluctuations by Takakura and Yousef (1975), and iii) other simplifications made in both works. Possible improvements to the simulations are discussed, including improvements to the emission processes and the coronal and beam conditions ( e.g., beam speed), in order to produce realistic stria/type IIIb bursts in f p emission.

  4. Stiffness of sphere-plate contacts at MHz frequencies: dependence on normal load, oscillation amplitude, and ambient medium.

    PubMed

    Vlachová, Jana; König, Rebekka; Johannsmann, Diethelm

    2015-01-01

    The stiffness of micron-sized sphere-plate contacts was studied by employing high frequency, tangential excitation of variable amplitude (0-20 nm). The contacts were established between glass spheres and the surface of a quartz crystal microbalance (QCM), where the resonator surface had been coated with either sputtered SiO2 or a spin-cast layer of poly(methyl methacrylate) (PMMA). The results from experiments undertaken in the dry state and in water are compared. Building on the shifts in the resonance frequency and resonance bandwidth, the instrument determines the real and the imaginary part of the contact stiffness, where the imaginary part quantifies dissipative processes. The method is closely analogous to related procedures in AFM-based metrology. The real part of the contact stiffness as a function of normal load can be fitted with the Johnson-Kendall-Roberts (JKR) model. The contact stiffness was found to increase in the presence of liquid water. This finding is tentatively explained by the rocking motion of the spheres, which couples to a squeeze flow of the water close to the contact. The loss tangent of the contact stiffness is on the order of 0.1, where the energy losses are associated with interfacial processes. At high amplitudes partial slip was found to occur. The apparent contact stiffness at large amplitude depends linearly on the amplitude, as predicted by the Cattaneo-Mindlin model. This finding is remarkable insofar, as the Cattaneo-Mindlin model assumes Coulomb friction inside the sliding region. Coulomb friction is typically viewed as a macroscopic concept, related to surface roughness. An alternative model (formulated by Savkoor), which assumes a constant frictional stress in the sliding zone independent of the normal pressure, is inconsistent with the experimental data. The apparent friction coefficients slightly increase with normal force, which can be explained by nanoroughness. In other words, contact splitting (i.e., a transport of

  5. Structures responsible for rapid fading of medium frequency radio reflections from the day-time E-layer

    NASA Astrophysics Data System (ADS)

    Jones, K. L.

    1984-12-01

    The steerable beam Bribie Island radar (152 deg E, 27 deg S) operating at a frequency of 1.98 MHz was used to obtain data relevant to reflection conditions near 100 km altitude on 7 days during June-October 1982. The rapid signal fading commonly observed is primarily due to transient reflectors with lifetimes of a few seconds, often seen up to angles of 20 deg from the zenith. Longer lived moving reflectors (presumed to be sporadic-E clouds) also play a part. Certain properties of the transient reflectors are consistent with a turbulent generation mechanism. However, any theory of their origin must explain why, for about a third of the time, they tend to occur preferentially to the north and east of the observing site. A direct comparison of velocities using Doppler and spaced antenna drifts methods shows reasonable agreement when the data is averaged over quarter hour periods. However, conclusions by previous workers, on the basis of observations of motions of diffraction patterns, that the ionospheric structure responsible for the diffraction pattern observed on the ground is undulations of the isoionic contours by gravity waves, is not supported by a detailed analysis of the data.

  6. Frequency and polymorphism of simple sequence repeats in a contiguous 685-kb DNA sequence containing the human T-cell receptor {beta}-chain gene complex

    SciTech Connect

    Charmley, P.; Concannon, P.; Hood, L.; Rowen, L.

    1995-10-10

    The human T-cell receptor {beta}-chain (TCRB) gene complex spans 575 kb in chromosome region 7q35 and has been the subject of a large-scale DNA sequencing effort. A contiguous 685-kb DNA sequence from this region was searched by computer analysis for the occurrence of simple sequence repeats (microsatellites) with core sequence lengths of 2-5 nucleotides. Twenty-nine such microsatellites of repeat number n {ge} 9 were found, with the majority being dinucleotide repeats. By PCR analysis, 19 were found to be polymorphic in repeat number, thus averaging one per 36 kb. These polymorphic di-, tri-, and tetranucleotide repeats had between 3 and 15 differently sized alleles each. The potential usefulness of these TCRB microsatellites for detecting disease susceptibility alleles was examined by measuring the linkage disequilibrium between these markers and flanking biallelic mutations. All but 4 microsatellites (79%) demonstrated significant linkage disequilibrium (P < 0.0001). This present study highlights the utility and potential outcomes of large-scale DNA sequencing for the identification of polymorphic simple sequence repeats. 20 refs., 2 figs., 1 tab.

  7. Low-frequency Observations of Linearly Polarized Structures in the Interstellar Medium near the South Galactic Pole

    NASA Astrophysics Data System (ADS)

    Lenc, E.; Gaensler, B. M.; Sun, X. H.; Sadler, E. M.; Willis, A. G.; Barry, N.; Beardsley, A. P.; Bell, M. E.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Callingham, J. R.; Cappallo, R. J.; Carroll, P.; Corey, B. E.; de Oliveira-Costa, A.; Deshpande, A. A.; Dillon, J. S.; Dwarkanath, K. S.; Emrich, D.; Ewall-Wice, A.; Feng, L.; For, B.-Q.; Goeke, R.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Hewitt, J. N.; Hindson, L.; Hurley-Walker, N.; Johnston-Hollitt, M.; Jacobs, D. C.; Kapińska, A. D.; Kaplan, D. L.; Kasper, J. C.; Kim, H.-S.; Kratzenberg, E.; Line, J.; Loeb, A.; Lonsdale, C. J.; Lynch, M. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Murphy, T.; Neben, A. R.; Oberoi, D.; Offringa, A. R.; Ord, S. M.; Paul, S.; Pindor, B.; Pober, J. C.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A. E. E.; Roshi, A.; Udaya Shankar, N.; Sethi, S. K.; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Sullivan, I. S.; Tegmark, M.; Thyagarajan, Nithyanandan; Tingay, S. J.; Trott, C.; Waterson, M.; Wayth, R. B.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L.; Wu, C.; Wyithe, J. S. B.; Zheng, Q.

    2016-10-01

    We present deep polarimetric observations at 154 MHz with the Murchison Widefield Array (MWA), covering 625 deg2 centered on α = 0hand δ = ‑27°. The sensitivity available in our deep observations allows an in-band, frequency-dependent analysis of polarized structure for the first time at long wavelengths. Our analysis suggests that the polarized structures are dominated by intrinsic emission but may also have a foreground Faraday screen component. At these wavelengths, the compactness of the MWA baseline distribution provides excellent snapshot sensitivity to large-scale structure. The observations are sensitive to diffuse polarized emission at ∼54‧ resolution with a sensitivity of 5.9 mJy beam‑1 and compact polarized sources at ∼2.‧4 resolution with a sensitivity of 2.3 mJy beam‑1 for a subset (400 deg2) of this field. The sensitivity allows the effect of ionospheric Faraday rotation to be spatially and temporally measured directly from the diffuse polarized background. Our observations reveal large-scale structures (∼1°–8° in extent) in linear polarization clearly detectable in ∼2 minute snapshots, which would remain undetectable by interferometers with minimum baseline lengths of >110 m at 154 MHz. The brightness temperature of these structures is on average 4 K in polarized intensity, peaking at 11 K. Rotation measure synthesis reveals that the structures have Faraday depths ranging from ‑2 to 10 rad m‑2 with a large fraction peaking at approximately +1 rad m‑2. We estimate a distance of 51 ± 20 pc to the polarized emission based on measurements of the in-field pulsar J2330–2005. We detect four extragalactic linearly polarized point sources within the field in our compact source survey. Based on the known polarized source population at 1.4 GHz and non-detections at 154 MHz, we estimate an upper limit on the depolarization ratio of 0.08 from 1.4 GHz to 154 MHz.

  8. Exploration of multi-fold symmetry element-loaded superconducting radio frequency structure for reliable acceleration of low- & medium-beta ion species

    SciTech Connect

    Huang, Shichun; Geng, Rongli

    2015-09-01

    Reliable acceleration of low- to medium-beta proton or heavy ion species is needed for future high-current superconducting radio frequency (SRF) accelerators. Due to the high-Q nature of an SRF resonator, it is sensitive to many factors such as electron loading (from either the accelerated beam or from parasitic field emitted electrons), mechanical vibration, and liquid helium bath pressure fluctuation etc. To increase the stability against those factors, a mechanically strong and stable RF structure is desirable. Guided by this consideration, multi-fold symmetry element-loaded SRF structures (MFSEL), cylindrical tanks with multiple (n>=3) rod-shaped radial elements, are being explored. The top goal of its optimization is to improve mechanical stability. A natural consequence of this structure is a lowered ratio of the peak surface electromagnetic field to the acceleration gradient as compared to the traditional spoke cavity. A disadvantage of this new structure is an increased size for a fixed resonant frequency and optimal beta. This paper describes the optimization of the electro-magnetic (EM) design and preliminary mechanical analysis for such structures.

  9. Sources and characteristics of medium-scale traveling ionospheric disturbances observed by high-frequency radars in the North American sector

    NASA Astrophysics Data System (ADS)

    Frissell, N. A.; Baker, J. B. H.; Ruohoniemi, J. M.; Greenwald, R. A.; Gerrard, A. J.; Miller, E. S.; West, M. L.

    2016-04-01

    Medium-scale traveling ionospheric disturbances (MSTIDs) are wave-like ionospheric perturbations routinely observed by high-frequency radars. We focus on a class of MSTIDs observed during the winter daytime at high latitudes and midlatitudes. The source of these MSTIDs remains uncertain, with the two primary candidates being space weather and lower atmospheric processes. We surveyed observations from four high-latitude and six midlatitude Super Dual Auroral Radar Network radars in the North American sector from November to May 2012 to 2015. The MSTIDs observed have horizontal wavelengths between ˜150 and 650 km and horizontal velocities between ˜75 and 325 m s-1. In local fall and winter seasons the majority of MSTIDs propagated equatorward, with bearings ranging from ˜125° to 225° geographic azimuth. No clear correlation with space weather activity as parameterized by AE and SYM-H could be identified. Rather, MSTID observations were found to have a strong correlation with polar vortex dynamics on two timescales. First, a seasonal timescale follows the annual development and decay of the polar vortex. Second, a shorter 2-4 week timescale again corresponds to synoptic polar vortex variability, including stratospheric warmings. Additionally, statistical analysis shows that MSTIDs are more likely during periods of strong polar vortex. Direct comparison of the MSTID observations with stratospheric zonal winds suggests that a wind filtering mechanism may be responsible for the strong correlation. Collectively, these observations suggest that polar atmospheric processes, rather than space weather activity, are primarily responsible for controlling the occurrence of high-latitude and midlatitude winter daytime MSTIDs.

  10. All-photonic quantum repeaters.

    PubMed

    Azuma, Koji; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2015-01-01

    Quantum communication holds promise for unconditionally secure transmission of secret messages and faithful transfer of unknown quantum states. Photons appear to be the medium of choice for quantum communication. Owing to photon losses, robust quantum communication over long lossy channels requires quantum repeaters. It is widely believed that a necessary and highly demanding requirement for quantum repeaters is the existence of matter quantum memories. Here we show that such a requirement is, in fact, unnecessary by introducing the concept of all-photonic quantum repeaters based on flying qubits. In particular, we present a protocol based on photonic cluster-state machine guns and a loss-tolerant measurement equipped with local high-speed active feedforwards. We show that, with such all-photonic quantum repeaters, the communication efficiency scales polynomially with the channel distance. Our result paves a new route towards quantum repeaters with efficient single-photon sources rather than matter quantum memories.

  11. All-photonic quantum repeaters

    PubMed Central

    Azuma, Koji; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2015-01-01

    Quantum communication holds promise for unconditionally secure transmission of secret messages and faithful transfer of unknown quantum states. Photons appear to be the medium of choice for quantum communication. Owing to photon losses, robust quantum communication over long lossy channels requires quantum repeaters. It is widely believed that a necessary and highly demanding requirement for quantum repeaters is the existence of matter quantum memories. Here we show that such a requirement is, in fact, unnecessary by introducing the concept of all-photonic quantum repeaters based on flying qubits. In particular, we present a protocol based on photonic cluster-state machine guns and a loss-tolerant measurement equipped with local high-speed active feedforwards. We show that, with such all-photonic quantum repeaters, the communication efficiency scales polynomially with the channel distance. Our result paves a new route towards quantum repeaters with efficient single-photon sources rather than matter quantum memories. PMID:25873153

  12. Allele frequencies of combined DNA index system (CODIS) and non-CODIS short tandem repeat loci in Goiás, Central Brazil.

    PubMed

    Rodovalho, R G; Santos, G S; Cavalcanti, L M; Moura, B F S M; Rodrigues, E L; Lima, P R; Gigonzac, M A D; Vieira, T C

    2015-07-03

    In studies of human identification, obtaining a high standard of outcomes and satisfactory conclusions are directly related to the use of highly polymorphic molecular markers. In addition to the combined DNA index system (CODIS) group, it is also important to implement non-CODIS markers into the analysis, as they increase the power of discrimination. During the identification process, it is essential to consider the genetic variation among distinct groups of populations, as the allele frequencies are directly associated with the power of discrimination. However, the population of Goiás, a State located in Central Brazil, is characterized by a highly mixed population due to its diverse ethnic origins. In this study, a survey of the allelic frequencies in the Goiás population was carried out using a molecular assembly composed of 21 autosomal loci both from and external to the CODIS group. The new data, for some of the markers used, were statistically similar to those from previous studies. This consistency means that the use of these markers might serve as a parameter for future population comparisons. The results from these analyses further our knowledge of the study of human identification.

  13. Medium-Sized Mammals around a Radioactive Liquid Waste Lagoon at Los Alamos National Laboratory: Uptake of Contaminants and Evaluation of Radio-Frequency Identification Technology

    SciTech Connect

    Leslie A. Hansen; Phil R. Fresquez; Rhonda J. Robinson; John D. Huchton; Teralene S. Foxx

    1999-11-01

    Use of a radioactive liquid waste lagoon by medium-sized mammals and levels of tritium, other selected radionuclides, and metals in biological tissues of the animals were documented at Technical Area 53 (TA-53) of Los Alamos National Laboratory during 1997 and 1998. Rock squirrel (Spermophilus variegates), raccoon (Procyon lotor), striped skunk (Mephitis mephitis), and bobcat (Lynx rufus) were captured at TA-53 and at a control site on the Santa Fe National Forest. Captured animals were anesthetized and marked with radio-frequency identification (RFD) tags and/or ear tags. We collected urine and hair samples for tritium and metals (aluminum, antimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, and thallium) analyses, respectively. In addition, muscle and bone samples from two rock squirrels collected from each of TA-53, perimeter, and regional background sites were tested for tritium, {sup 137}Cs, {sup 90}Sr, {sup 238}Pu, {sup 239,240}Pu, {sup 241}Am, and total uranium. Animals at TA-53 were monitored entering and leaving the lagoon area using a RFID monitor to read identification numbers from the RFID tags of marked animals and a separate camera system to photograph all animals passing through the monitor. Cottontail rabbit (Sylvilagus spp.), rock squirrel, and raccoon were the species most frequently photographed going through the RFID monitor. Less than half of all marked animals in the lagoon area were detected using the lagoon. Male and female rock squirrels from the lagoon area had significantly higher tritium concentrations compared to rock squirrels from the control area. Metals tested were not significantly higher in rock squirrels from TA-53, although there was a trend toward increased levels of lead in some individuals at TA-53. Muscle and bone samples from squirrels in the lagoon area appeared to have higher levels of tritium, total uranium, and {sup 137}Cs than samples collected from perimeter and

  14. Diverging frequency-modulated 50-kHz vocalization, locomotor activity and conditioned place preference effects in rats given repeated amphetamine treatment.

    PubMed

    Taracha, Ewa; Kaniuga, Ewelina; Chrapusta, Stanisław J; Maciejak, Piotr; Sliwa, Lech; Hamed, Adam; Krząścik, Paweł

    2014-08-01

    Behavioral sensitization and tolerance to repetitive exposure to addictive drugs are commonly used for the assessment of the early stages of the drug dependence progress in animals. The orchestra of tools for studying the progress of drug dependence in laboratory rodents has been considerably enriched in the 1980s by the introduction of ultrasonic vocalization (USV) detection and characterization. However, the relationship between the results of this technology and those of traditional behavioral tests is not clear. We attempted to elucidate some of the respective ambiguities by comparing the effects of an intermittent amphetamine treatment, which was aimed both at the induction of sensitization and tolerance to this drug and at testing the persistence of these effects, on the locomotor activity and 50-kHz USV responses to both the drug and the context of drug exposure in adult male rats showing diverging susceptibility for sensitization to amphetamine. Categorization of the rats into low and high responders/callers based on sensitization of their frequency-modulated 50-kHz USV responsiveness showed some correspondence with conditioned place preference effects, but not with responses to amphetamine. The study showed distinct changes in the rate and latency of the frequency-modulated 50-kHz USV responses to repetitive amphetamine treatment, which were reminiscent of classical behavioral signs of sensitization and tolerance. These results show the utility of the appetitive USV for monitoring of early phases of complex processes leading to drug dependence. However, USV, locomotor activity and conditioned place preference seem to reflect different aspects of these phenomena.

  15. Protocol of the adaptive study of IL-2 dose frequency on regulatory T cells in type 1 diabetes (DILfrequency): a mechanistic, non-randomised, repeat dose, open-label, response-adaptive study

    PubMed Central

    Truman, Lucy A; Pekalski, Marcin L; Kareclas, Paula; Evangelou, Marina; Walker, Neil M; Howlett, James; Mander, Adrian P; Kennet, Jane; Wicker, Linda S; Bond, Simon; Todd, John A; Waldron-Lynch, Frank

    2015-01-01

    Introduction Type 1 diabetes (T1D) is caused by autoimmune destruction of the insulin-producing β cells in the pancreatic islets, leading to insulinopenia and hyperglycaemia. Genetic analyses indicate that alterations of the interleukin-2 (IL-2) pathway mediating immune activation and tolerance predispose to T1D, specifically the polymorphic expression of the IL-2 receptor-α chain (CD25) on T lymphocytes. Replacement of physiological doses of IL-2 could restore self-tolerance and prevent further autoimmunity by enhancing the function of CD4+ T regulatory cells (Tregs) to limit the activation of auto reactive T effector cells (Teffs). In this experimental medicine study, we use an adaptive trial design to determine the optimal dosing regimen for IL-2 to improve Treg function while limiting activation of Teffs in participants with T1D. Methods and analysis The Adaptive study of IL-2 dose frequency on Tregs in type 1 diabetes(DILfrequency) is a mechanistic, non-randomised, repeat dose open-label, response-adaptive study of 36 participants with T1D. The objective is to establish the optimal dose and frequency of ultra-low dose IL-2: to increase Treg frequency within the physiological range, to increase CD25 expression on Tregs, without increasing CD4+ Teffs. DILfrequency has an initial learning phase where 12 participants are allocated to six different doses and frequencies followed by an interim statistical analysis. After analysis of the learning phase, the Dose and Frequency Committee will select the optimal targets for Treg frequency, Treg CD25 expression and Teff frequency. Three groups of eight participants will be treated consecutively in the confirming phase. Each dose and frequency selected will be based on statistical analysis of all data collected from the previous groups. Ethics Ethical approval for DILfrequency was granted on 12 August 2014. Results The results of this study will be reported, through peer-reviewed journals, conference presentations and

  16. Imaging the hydrothermal system beneath the Jigokudani valley, Tateyama volcano, Japan: implications for structures controlling repeated phreatic eruptions from an audio-frequency magnetotelluric survey

    NASA Astrophysics Data System (ADS)

    Seki, Kaori; Kanda, Wataru; Ogawa, Yasuo; Tanbo, Toshiya; Kobayashi, Tomokazu; Hino, Yuta; Hase, Hideaki

    2015-01-01

    This study focuses on the results of an audio-frequency magnetotelluric (AMT) survey across the Jigokudani valley, Tateyama volcano, Japan, to investigate the spatial relationship between the distribution of electrical resistivity and geothermal activity and to elucidate the geologic controls on both its phreatic eruption history and recent increase in phreatic activity. The AMT data were collected at eight locations across the Jigokudani valley in September 2013, with high quality data obtained from most sites, enabling the identification of an underground 2D resistivity structure from the transverse magnetic (TM) mode data. The data obtained during this study provided evidence of a large conductive region beneath the surface of the Jigokudani valley that is underlain by a resistive layer at depths below 500 m. The resistive layer is cut by a relatively conductive region that extends subvertically toward the shallow conductor. The shallow conductive region is divided into an uppermost slightly conductive section that is thought to be a lacustrine sediment layer of an extinct crater lake containing hydrothermal fluids and a lower section containing a mix of volcanic gases and hydrothermal fluids. The low permeability of the clay zone means that the uppermost clayey sediments allow the accumulation of gases in the lower section of the conductive region, suggesting the existence of a cap structure. The deep resistive layer likely consists of units similar to the granitic rocks that are widely exposed throughout the Jigokudani valley. We suggest that the relatively conductive zone that separates these granitic rocks represents a high-temperature volcanic gas conduit, given that the most active fumarole in the Jigokudani valley lies directly along the trajectory of this path.

  17. 78 FR 65594 - Vehicular Repeaters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-01

    ... mobile repeaters by public safety licensees on certain frequencies in the VHF band. DATES: Submit..., CART, etc.) by email: FCC504@fcc.gov or phone: 202-418- 0530 or TTY: 202-418-0432. For detailed... Proceedings, 63 FR 24121 (May 1, 1998). Electronic Filers: Comments may be filed electronically using...

  18. Review of rigorous coupled-wave analysis and of homogeneous effective medium approximations for high spatial-frequency surface-relief gratings

    NASA Technical Reports Server (NTRS)

    Glytsis, Elias N.; Brundrett, David L.; Gaylord, Thomas K.

    1993-01-01

    A review of the rigorous coupled-wave analysis as applied to the diffraction of electro-magnetic waves by gratings is presented. The analysis is valid for any polarization, angle of incidence, and conical diffraction. Cascaded and/or multiplexed gratings as well as material anisotropy can be incorporated under the same formalism. Small period rectangular groove gratings can also be modeled using approximately equivalent uniaxial homogeneous layers (effective media). The ordinary and extraordinary refractive indices of these layers depend on the gratings filling factor, the refractive indices of the substrate and superstrate, and the ratio of the freespace wavelength to grating period. Comparisons of the homogeneous effective medium approximations with the rigorous coupled-wave analysis are presented. Antireflection designs (single-layer or multilayer) using the effective medium models are presented and compared. These ultra-short period antireflection gratings can also be used to produce soft x-rays. Comparisons of the rigorous coupled-wave analysis with experimental results on soft x-ray generation by gratings are also included.

  19. Repeat-until-success quantum repeaters

    NASA Astrophysics Data System (ADS)

    Bruschi, David Edward; Barlow, Thomas M.; Razavi, Mohsen; Beige, Almut

    2014-09-01

    We propose a repeat-until-success protocol to improve the performance of probabilistic quantum repeaters. Conventionally, these rely on passive static linear-optics elements and photodetectors to perform Bell-state measurements (BSMs) with a maximum success rate of 50%. This is a strong impediment for entanglement swapping between distant quantum memories. Every time a BSM fails, entanglement needs to be redistributed between the corresponding memories in the repeater link. The key ingredients of our scheme are repeatable BSMs. Under ideal conditions, these turn probabilistic quantum repeaters into deterministic ones. Under realistic conditions, our protocol too might fail. However, using additional threshold detectors now allows us to improve the entanglement generation rate by almost orders of magnitude, at a nominal distance of 1000 km, compared to schemes that rely on conventional BSMs. This improvement is sufficient to make the performance of our scheme comparable to the expected performance of some deterministic quantum repeaters.

  20. Low and then high frequency oscillations of distinct right cortical networks are progressively enhanced by medium and long term Satyananda Yoga meditation practice

    PubMed Central

    Thomas, John; Jamieson, Graham; Cohen, Marc

    2014-01-01

    Meditation proficiency is related to trait-like (learned) effects on brain function, developed over time. Previous studies show increases in EEG power in lower frequency bands (theta, alpha) in experienced meditators in both meditation states and baseline conditions. Higher gamma band power has been found in advanced Buddhist meditators, yet it is not known if this occurs in Yoga meditation practices. This study used eLORETA to compare differences in cortical source activity underlying scalp EEG from intermediate (mean experience 4 years) and advanced (mean experience 30 years) Australian meditators from the Satyananda Yoga tradition during a body-steadiness meditation, mantra meditation, and non-meditation mental calculation condition. Intermediate Yoga meditators showed greater source activity in low frequencies (particularly theta and alpha1) during mental calculation, body-steadiness and mantra meditation. A similar spatial pattern of significant differences was found in all conditions but the number of significant voxels was double during body-steadiness and mantra meditation than in the non-meditation (calculation) condition. These differences were greatest in right (R) superior frontal and R precentral gyri and extended back to include the R parietal and occipital lobes. Advanced Yoga meditators showed greater activity in high frequencies (beta and especially gamma) in all conditions but greatly expanded during meditation practice. Across all conditions (meditation and non-meditation) differences were greatest in the same regions: R insula, R inferior frontal gyrus and R anterior temporal lobe. Distinct R core networks were identified in alpha1 (8–10 Hz) and gamma (25–42 Hz) bands, respectively. The voxels recruited to these networks greatly expanded during meditation practice to include homologous regions of the left hemisphere. Functional interpretation parallels traditionally described stages of development in Yoga proficiency. PMID:24959124

  1. Low and then high frequency oscillations of distinct right cortical networks are progressively enhanced by medium and long term Satyananda Yoga meditation practice.

    PubMed

    Thomas, John; Jamieson, Graham; Cohen, Marc

    2014-01-01

    Meditation proficiency is related to trait-like (learned) effects on brain function, developed over time. Previous studies show increases in EEG power in lower frequency bands (theta, alpha) in experienced meditators in both meditation states and baseline conditions. Higher gamma band power has been found in advanced Buddhist meditators, yet it is not known if this occurs in Yoga meditation practices. This study used eLORETA to compare differences in cortical source activity underlying scalp EEG from intermediate (mean experience 4 years) and advanced (mean experience 30 years) Australian meditators from the Satyananda Yoga tradition during a body-steadiness meditation, mantra meditation, and non-meditation mental calculation condition. Intermediate Yoga meditators showed greater source activity in low frequencies (particularly theta and alpha1) during mental calculation, body-steadiness and mantra meditation. A similar spatial pattern of significant differences was found in all conditions but the number of significant voxels was double during body-steadiness and mantra meditation than in the non-meditation (calculation) condition. These differences were greatest in right (R) superior frontal and R precentral gyri and extended back to include the R parietal and occipital lobes. Advanced Yoga meditators showed greater activity in high frequencies (beta and especially gamma) in all conditions but greatly expanded during meditation practice. Across all conditions (meditation and non-meditation) differences were greatest in the same regions: R insula, R inferior frontal gyrus and R anterior temporal lobe. Distinct R core networks were identified in alpha1 (8-10 Hz) and gamma (25-42 Hz) bands, respectively. The voxels recruited to these networks greatly expanded during meditation practice to include homologous regions of the left hemisphere. Functional interpretation parallels traditionally described stages of development in Yoga proficiency. PMID:24959124

  2. Reduced supplementation frequency increased insulin-like growth factor 1 in beef steers fed medium quality hay and supplemented with a soybean hull and corn gluten feed blend.

    PubMed

    Drewnoski, M E; Huntington, G B; Poore, M H

    2014-06-01

    Reducing supplementation frequency in calf growing programs can reduce labor and equipment operation costs. However, little is understood about the metabolic response of ruminants to large fluctuations in nutrient intake. Eighteen Angus or Angus × Simmental cross steers (287 ± 20 kg and 310 ± 3.6 d of age) were individually fed 1 of 3 dietary treatments using Calan gates. Dietary treatments consisted of ad libitum hay and no supplement (NS), ad libitum hay and 1% BW (as-fed basis) of supplement daily (DS), or ad libitum hay and 2% BW (as-fed basis) of supplement every other day (SA). The supplement was 90% DM and contained (as-fed basis) 47% corn gluten feed, 47% soybean hulls, 2% feed grade limestone, and 4% molasses. Hay intake and ADG was measured over a 52-d period. Steers were then moved to individual tie stalls. Steers were fed at 0800 h and blood samples were collected every hour from 0600 to 1400 h and at 1800, 2200, and 0200 h over a 2-d period. Gains were increased (P < 0.01) by supplementation but did not differ (P = 0.68) due to supplementation frequency. Average daily gain was 0.45, 0.90, and 0.87 kg ·hd(-1)·d(-1) (SEM ± 0.05) for steers NS, DS, and SA, respectively. Across the 2-d supplementation cycle area under the concentration time curve (AUC) for plasma glucose was increased (P < 0.01) by supplementation but did not differ (P = 0.41) due to supplementation frequency. The AUC for plasma insulin was increased by supplementation (P < 0.01) but did not differ (P = 0.67) due to supplementation frequency. Plasma IGF-1 was increased (P = 0.01) by supplementation and was greater (P = 0.04) for steers supplemented SA than DS. Gains of steers supplemented with a soybean hull and corn gluten feed blend on alternate days did not differ from those supplemented daily suggesting the steers were able to efficiently utilize large boluses of nutrients fed every other day. The effect of less frequent supplementation on IGF-1 deserves further examination as

  3. Efficient generation of high-frequency terahertz waves from highly lossy second-order nonlinear medium at polariton resonance under transverse-pumping geometry.

    PubMed

    Ding, Yujie J

    2010-01-15

    Owing to strong coupling between transverse-optical phonons and high-frequency terahertz waves in zinc-blende semiconductors, second-order nonlinear coefficients can be dramatically enhanced within the forbidden band of the polariton resonance. However, linear absorption in this regime is also dramatically increased. We show that transverse-pumping geometry can be exploited for achieving an efficient terahertz generation at the polariton resonance. Our estimates illustrate that pump powers as low as 100 mW are sufficient for causing the significant depletion of the pump beams.

  4. A Repeat Look at Repeating Patterns

    ERIC Educational Resources Information Center

    Markworth, Kimberly A.

    2016-01-01

    A "repeating pattern" is a cyclical repetition of an identifiable core. Children in the primary grades usually begin pattern work with fairly simple patterns, such as AB, ABC, or ABB patterns. The unique letters represent unique elements, whereas the sequence of letters represents the core that is repeated. Based on color, shape,…

  5. Validation of soy protein estimates from a food-frequency questionnaire with repeated 24-h recalls and isoflavonoid excretion in overnight urine in a Western population with a wide range of soy intakes2

    PubMed Central

    Jaceldo-Siegl, Karen; Fraser, Gary E; Chan, Jacqueline; Franke, Adrian; Sabaté, Joan

    2013-01-01

    Background Evidence of the benefits of soy on cancer risk in Western populations is inconsistent, in part because of the low intake of soy in these groups. Objective We assessed the validity of soy protein estimates from food-frequency questionnaires (FFQs) in a sample of Adventist Health Study-2 participants with a wide range of soy intakes. Design We obtained dietary intake data from 100 men and women (43 blacks and 57 nonblacks). Soy protein estimates from FFQs were compared against repeated 24-h recalls and urinary excretion of daidzein, genistein, total isoflavonoids (TIFLs), and equol (measured by HPLC/photodiode array/mass spectrometry) as reference criteria. We calculated Pearson and Spearman correlation coefficients (with 95% CIs) for FFQ–24-h recall, 24 h-recall–urinary excretion, and FFQ–urinary excretion pairs. Results Among soy users, mean (± SD) soy protein values were 12.12 ± 10.80 g/d from 24-h recalls and 9.43 ± 7.83 g/d from FFQs. The unattenuated correlation (95% CI) between soy protein estimates from 24-h recalls and FFQs was 0.57 (0.32, 0.75). Correlation coefficients between soy protein intake from 24-h recalls and urinary isoflavonoids were 0.72 (0.43, 0.96) for daidzein, 0.67 (0.43, 0.91) for genistein, and 0.72 (0.47, 0.98) for TIFLs. Between FFQs and urinary excretion, these were 0.50 (0.32, 0.65), 0.48 (0.29, 0.61), and 0.50 (0.32, 0.64) for daidzein, genistein, and TIFLs, respectively. Conclusions Soy protein estimates from questionnaire were significantly correlated with soy protein from 24-h recalls and urinary excretion of daidzein, genistein, and TIFLs. The Adventist Health Study-2 FFQ is a valid instrument for assessing soy protein in a population with a wide range of soy intakes. PMID:18469267

  6. The new Adelaide medium frequency Doppler radar

    NASA Astrophysics Data System (ADS)

    Reid, I. M.; Vandepeer, B. G. W.; Dillon, S.; Fuller, B.

    1993-08-01

    The Buckland Park Aerial Array (35 deg S, 138 deg E) is situated about 40 km north of Adelaide on a flat coastal plain. It was designed by Basil Briggs and Graham Elford, and constructed between 1965 and 1968. The first results were published in the late 1960's. Some aspects of the history of the array are described in Briggs (1993). A new MF Doppler Radar utilizing the array has been developed. This paper describes some of the technical details of this new facility.

  7. Revisiting the TALE repeat.

    PubMed

    Deng, Dong; Yan, Chuangye; Wu, Jianping; Pan, Xiaojing; Yan, Nieng

    2014-04-01

    Transcription activator-like (TAL) effectors specifically bind to double stranded (ds) DNA through a central domain of tandem repeats. Each TAL effector (TALE) repeat comprises 33-35 amino acids and recognizes one specific DNA base through a highly variable residue at a fixed position in the repeat. Structural studies have revealed the molecular basis of DNA recognition by TALE repeats. Examination of the overall structure reveals that the basic building block of TALE protein, namely a helical hairpin, is one-helix shifted from the previously defined TALE motif. Here we wish to suggest a structure-based re-demarcation of the TALE repeat which starts with the residues that bind to the DNA backbone phosphate and concludes with the base-recognition hyper-variable residue. This new numbering system is consistent with the α-solenoid superfamily to which TALE belongs, and reflects the structural integrity of TAL effectors. In addition, it confers integral number of TALE repeats that matches the number of bound DNA bases. We then present fifteen crystal structures of engineered dHax3 variants in complex with target DNA molecules, which elucidate the structural basis for the recognition of bases adenine (A) and guanine (G) by reported or uncharacterized TALE codes. Finally, we analyzed the sequence-structure correlation of the amino acid residues within a TALE repeat. The structural analyses reported here may advance the mechanistic understanding of TALE proteins and facilitate the design of TALEN with improved affinity and specificity.

  8. POLE-ZERO Cancellation in Structures: Repeated Roots

    NASA Astrophysics Data System (ADS)

    MOTTERSHEAD, J. E.; LI, T.; HE, J.

    2000-03-01

    The conditions for the creation of nodes of normal modes of vibration from the cancellation of poles and zeros are established when either the poles or the zeros (or both) appear as repeated eigenvalues. The analysis is illustrated by numerical examples including the case of a pole-zero cancellation at every co-ordinate at the same frequency which is shown to occur whenever there are repeated poles. If there are repeated poles and repeated zeros at the same frequency then the number of poles must be either one more, one less or equal to the number of zeros.

  9. Population frequency for the short tandem repeat loci D18S849, D3S1744, and D12S1090 in Caucasian-Mestizo and African descent populations of Colombia.

    PubMed

    Yunis, J J; Garcia, O; Baena, A; Arboleda, G; Uriarte, I; Yunis, E

    2000-03-01

    Blood samples from 489 unrelated Caucasian Mestizo and 252 individuals of African descent in Colombia were amplified and typed for three short tandem repeat (STR) markers (D12S1090, D3S1744, and D18S849). All markers conformed to Hardy-Weinberg equilibrium expectations in both populations studied. In addition, heterozygosity, mean exclusion chance, polymorphism information content, discrimination power, and the assumption of independence within and between loci were determined. The mean exclusion chance for all three STR markers is 0.9750 in the Caucasian Mestizo population and 0.9731 in the African Colombian Population. The discrimination power is 0.999925 and 0.999911 in the Caucasian Mestizo and African Colombian respectively. PMID:10782966

  10. Honesty through repeated interactions.

    PubMed

    Rich, Patricia; Zollman, Kevin J S

    2016-04-21

    In the study of signaling, it is well known that the cost of deception is an essential element for stable honest signaling in nature. In this paper, we show how costs for deception can arise endogenously from repeated interactions between individuals. Utilizing the Sir Philip Sidney game as an illustrative case, we show that repeated interactions can sustain honesty with no observable signal costs, even when deception cannot be directly observed. We provide a number of potential experimental tests for this theory which distinguish it from the available alternatives.

  11. Frequency Tunable Wire Lasers

    NASA Technical Reports Server (NTRS)

    Hu, Qing (Inventor)

    2013-01-01

    The present invention provides frequency tunable solid-state radiation-generating devices, such as lasers and amplifiers, whose active medium has a size in at least one transverse dimension (e.g., its width) that is much smaller than the wavelength of radiation generated and/or amplified within the active medium. In such devices, a fraction of radiation travels as an evanescent propagating mode outside the active medium. It has been discovered that in such devices the radiation frequency can be tuned by the interaction of a tuning mechanism with the propagating evanescent mode.

  12. Frequency set on systems

    NASA Astrophysics Data System (ADS)

    Wilby, W. A.; Brett, A. R. H.

    Frequency set on techniques used in ECM applications include repeater jammers, frequency memory loops (RF and optical), coherent digital RF memories, and closed loop VCO set on systems. Closed loop frequency set on systems using analog phase and frequency locking are considered to have a number of cost and performance advantages. Their performance is discussed in terms of frequency accuracy, bandwidth, locking time, stability, and simultaneous signals. Some experimental results are presented which show typical locking performance. Future ECM systems might require a response to very short pulses. Acoustooptic and fiber-optic pulse stretching techniques can be used to meet such requirements.

  13. Slit Wheel Repeatability

    NASA Astrophysics Data System (ADS)

    DiFelice, Audrey

    2012-10-01

    Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 19 Program 12771.

  14. Slit Wheel Repeatability

    NASA Astrophysics Data System (ADS)

    Long, Chris

    2011-10-01

    Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 18 Program 12410.

  15. Slit Wheel Repeatability

    NASA Astrophysics Data System (ADS)

    DiFelice, Audrey

    2013-10-01

    Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 20 Program 13140.

  16. Slit Wheel Repeatability

    NASA Astrophysics Data System (ADS)

    Zheng, Wei

    2010-09-01

    Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 17 Program 11851.

  17. Repeated Causal Decision Making

    ERIC Educational Resources Information Center

    Hagmayer, York; Meder, Bjorn

    2013-01-01

    Many of our decisions refer to actions that have a causal impact on the external environment. Such actions may not only allow for the mere learning of expected values or utilities but also for acquiring knowledge about the causal structure of our world. We used a repeated decision-making paradigm to examine what kind of knowledge people acquire in…

  18. All-optical repeater.

    PubMed

    Silberberg, Y

    1986-06-01

    An all-optical device containing saturable gain, saturable loss, and unsaturable loss is shown to transform weak, distorted optical pulses into uniform standard-shape pulses. The proposed device performs thresholding, amplification, and pulse shaping as required from an optical repeater. It is shown that such a device could be realized by existing semiconductor technology.

  19. Bidirectional Manchester repeater

    NASA Technical Reports Server (NTRS)

    Ferguson, J.

    1980-01-01

    Bidirectional Manchester repeater is inserted at periodic intervals along single bidirectional twisted pair transmission line to detect, amplify, and transmit bidirectional Manchester 11 code signals. Requiring only 18 TTL 7400 series IC's, some line receivers and drivers, and handful of passive components, circuit is simple and relatively inexpensive to build.

  20. Practical quantum repeaters with parametric down-conversion sources

    NASA Astrophysics Data System (ADS)

    Krovi, Hari; Guha, Saikat; Dutton, Zachary; Slater, Joshua A.; Simon, Christoph; Tittel, Wolfgang

    2016-03-01

    Conventional wisdom suggests that realistic quantum repeaters will require quasi-deterministic sources of entangled photon pairs. In contrast, we here study a quantum repeater architecture that uses simple parametric down-conversion sources, as well as frequency-multiplexed multimode quantum memories and photon-number-resolving detectors. We show that this approach can significantly extend quantum communication distances compared to direct transmission. This shows that important trade-offs are possible between the different components of quantum repeater architectures.

  1. Using quasiphotons to compute wave fields in an elastic medium

    SciTech Connect

    Kachalov, A.P.

    1987-07-10

    Quasiphoton solutions are constructed for longitudinal and transversal waves in an elastic medium. The quasiphotons are then applied to determine the fields of nonstationary high-frequency point sources in a medium with parameters dependent on two Euclidean coordinates.

  2. Frequency discriminating laser

    SciTech Connect

    Thomas, M.D.

    1987-10-20

    A laser is described for discriminating between a higher gain transition and a lower gain transition to permit the laser to lase at the lower gain transition. It consists of: a laser cavity, including more than two mirrors each of which is highly transmissive at the frequency of the higher gain transition, one of which is partially reflective at the frequency of the lower gain transition, and all but the one of which are highly reflective at the frequency of the lower gain transition; an active laser medium disposed within the cavity; and means for pumping the active laser medium.

  3. Duct Leakage Repeatability Testing

    SciTech Connect

    Walker, Iain; Sherman, Max

    2014-01-01

    Duct leakage often needs to be measured to demonstrate compliance with requirements or to determine energy or Indoor Air Quality (IAQ) impacts. Testing is often done using standards such as ASTM E1554 (ASTM 2013) or California Title 24 (California Energy Commission 2013 & 2013b), but there are several choices of methods available within the accepted standards. Determining which method to use or not use requires an evaluation of those methods in the context of the particular needs. Three factors that are important considerations are the cost of the measurement, the accuracy of the measurement and the repeatability of the measurement. The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards.

  4. Accumulate repeat accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative channel coding scheme called 'Accumulate Repeat Accumulate codes' (ARA). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes, thus belief propagation can be used for iterative decoding of ARA codes on a graph. The structure of encoder for this class can be viewed as precoded Repeat Accumulate (RA) code or as precoded Irregular Repeat Accumulate (IRA) code, where simply an accumulator is chosen as a precoder. Thus ARA codes have simple, and very fast encoder structure when they representing LDPC codes. Based on density evolution for LDPC codes through some examples for ARA codes, we show that for maximum variable node degree 5 a minimum bit SNR as low as 0.08 dB from channel capacity for rate 1/2 can be achieved as the block size goes to infinity. Thus based on fixed low maximum variable node degree, its threshold outperforms not only the RA and IRA codes but also the best known LDPC codes with the dame maximum node degree. Furthermore by puncturing the accumulators any desired high rate codes close to code rate 1 can be obtained with thresholds that stay close to the channel capacity thresholds uniformly. Iterative decoding simulation results are provided. The ARA codes also have projected graph or protograph representation that allows for high speed decoder implementation.

  5. Acoustic resonance frequency locked photoacoustic spectrometer

    DOEpatents

    Pilgrim, Jeffrey S.; Bomse, David S.; Silver, Joel A.

    2003-09-09

    A photoacoustic spectroscopy method and apparatus for maintaining an acoustic source frequency on a sample cell resonance frequency comprising: providing an acoustic source to the sample cell, the acoustic source having a source frequency; repeatedly and continuously sweeping the source frequency across the resonance frequency at a sweep rate; and employing an odd-harmonic of the source frequency sweep rate to maintain the source frequency sweep centered on the resonance frequency.

  6. Coexistence of 3G repeaters with LTE base stations.

    PubMed

    Yeo, Woon-Young; Lee, Sang-Min; Hwang, Gyung-Ho; Kim, Jae-Hoon

    2013-01-01

    Repeaters have been an attractive solution for mobile operators to upgrade their wireless networks at low cost and to extend network coverage effectively. Since the first LTE commercial deployment in 2009, many mobile operators have launched LTE networks by upgrading their 3G and legacy networks. Because all 3G frequency bands are shared with the frequency bands for LTE deployment and 3G mobile operators have an enormous number of repeaters, reusing 3G repeaters in LTE networks is definitely a practical and cost-efficient solution. However, 3G repeaters usually do not support spatial multiplexing with multiple antennas, and thus it is difficult to reuse them directly in LTE networks. In order to support spatial multiplexing of LTE, the role of 3G repeaters should be replaced with small LTE base stations or MIMO-capable repeaters. In this paper, a repeater network is proposed to reuse 3G repeaters in LTE deployment while still supporting multilayer transmission of LTE. Interestingly, the proposed network has a higher cluster throughput than an LTE network with MIMO-capable repeaters.

  7. Coexistence of 3G Repeaters with LTE Base Stations

    PubMed Central

    Yeo, Woon-Young

    2013-01-01

    Repeaters have been an attractive solution for mobile operators to upgrade their wireless networks at low cost and to extend network coverage effectively. Since the first LTE commercial deployment in 2009, many mobile operators have launched LTE networks by upgrading their 3G and legacy networks. Because all 3G frequency bands are shared with the frequency bands for LTE deployment and 3G mobile operators have an enormous number of repeaters, reusing 3G repeaters in LTE networks is definitely a practical and cost-efficient solution. However, 3G repeaters usually do not support spatial multiplexing with multiple antennas, and thus it is difficult to reuse them directly in LTE networks. In order to support spatial multiplexing of LTE, the role of 3G repeaters should be replaced with small LTE base stations or MIMO-capable repeaters. In this paper, a repeater network is proposed to reuse 3G repeaters in LTE deployment while still supporting multilayer transmission of LTE. Interestingly, the proposed network has a higher cluster throughput than an LTE network with MIMO-capable repeaters. PMID:24459420

  8. Duct Leakage Repeatability Testing

    SciTech Connect

    Walker, Iain; Sherman, Max

    2014-08-01

    The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques for duct leakage using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards. The three duct leak measurement methods assessed in this report are the two duct pressurization methods that are commonly used by many practitioners and the DeltaQ technique. These are methods B, C and A, respectively of the ASTM E1554 standard. Although it would be useful to evaluate other duct leak test methods, this study focused on those test methods that are commonly used and are required in various test standards, such as BPI (2010), RESNET (2014), ASHRAE 62.2 (2013), California Title 24 (CEC 2012), DOE Weatherization and many other energy efficiency programs.

  9. Repeated measures with zeros.

    PubMed

    Berk, K N; Lachenbruch, P A

    2002-08-01

    Consider repeated measures data with many zeros. For the case with one grouping factor and one repeated measure, we examine several models, assuming that the nonzero data are roughly lognormal. One of the simplest approaches is to model the zeros as left-censored observations from the lognormal distribution. A random effect is assumed for subjects. The censored model makes a strong assumption about the relationship between the zeros and the nonzero values. To check on this, you can instead assume that some of the zeros are 'true' zeros and model them as Bernoulli. Then the other values are modeled with a censored lognormal. A logistic model is used for the Bernoulli p, the probability of a true nonzero. The fit of the pure left-censored lognormal can be assessed by testing the hypothesis that p is 1, as described by Moulton and Halsey. The model can also be simplified by omitting the censoring, leaving a logistic model for the zeros and a lognormal model for the nonzero values. This is approximately equivalent to modeling the zero and nonzero values separately, a two-part model. In contrast to the censored model, this model assumes only a slight relationship (a covariance component) between the occurrence of zeros and the size of the nonzero values. The models are compared in terms of an example with data from children's private speech. PMID:12197298

  10. Survey of simple sequence repeats in woodland strawberry (Fragaria vesca).

    PubMed

    Guan, L; Huang, J F; Feng, G Q; Wang, X W; Wang, Y; Chen, B Y; Qiao, Y S

    2013-07-30

    The use of simple sequence repeats (SSRs), or microsatellites, as genetic markers has become popular due to their abundance and variation in length among individuals. In this study, we investigated linkage groups (LGs) in the woodland strawberry (Fragaria vesca) and demonstrated variation in the abundances, densities, and relative densities of mononucleotide, dinucleotide, and trinucleotide repeats. Mononucleotide, dinucleotide, and trinucleotide repeats were more common than longer repeats in all LGs examined. Perfect SSRs were the predominant SSR type found and their abundance was extremely stable among LGs and chloroplasts. Abundances of mononucleotide, dinucleotide, and trinucleotide repeats were positively correlated with LG size, whereas those of tetranucleotide and hexanucleotide SSRs were not. Generally, in each LG, the abundance, relative abundance, relative density, and the proportion of each unique SSR all declined rapidly as the repeated unit increased. Furthermore, the lengths and frequencies of SSRs varied among different LGs.

  11. Additional waves in the graphene layered medium.

    PubMed

    Chern, Ruey-Lin; Han, Dezhuan; Zhang, Z Q; Chan, C T

    2014-12-29

    We investigate the features of additional waves that arise in the graphene layered medium, within the framework of nonlocal effective medium model. The additional wave is manifest on the biquadratic dispersion relation of the medium and represents as a distinctive nonlocal character at long wavelength. In particular, the reflection and transmission coefficients for the nonlocal medium are underdetermined by Maxwell's boundary conditions. An additional boundary condition based on modal expansions is proposed to derive the generalized Fresnel equations, based on which the additional wave in the graphene layered medium is determined. The additional wave tends to be significant near the effective plasma frequency, near which the graphene plasmons are excited inside the medium. PMID:25607138

  12. Repeat Customer Success in Extension

    ERIC Educational Resources Information Center

    Bess, Melissa M.; Traub, Sarah M.

    2013-01-01

    Four multi-session research-based programs were offered by two Extension specialist in one rural Missouri county. Eleven participants who came to multiple Extension programs could be called "repeat customers." Based on the total number of participants for all four programs, 25% could be deemed as repeat customers. Repeat customers had…

  13. RepeatsDB: a database of tandem repeat protein structures

    PubMed Central

    Di Domenico, Tomás; Potenza, Emilio; Walsh, Ian; Gonzalo Parra, R.; Giollo, Manuel; Minervini, Giovanni; Piovesan, Damiano; Ihsan, Awais; Ferrari, Carlo; Kajava, Andrey V.; Tosatto, Silvio C.E.

    2014-01-01

    RepeatsDB (http://repeatsdb.bio.unipd.it/) is a database of annotated tandem repeat protein structures. Tandem repeats pose a difficult problem for the analysis of protein structures, as the underlying sequence can be highly degenerate. Several repeat types haven been studied over the years, but their annotation was done in a case-by-case basis, thus making large-scale analysis difficult. We developed RepeatsDB to fill this gap. Using state-of-the-art repeat detection methods and manual curation, we systematically annotated the Protein Data Bank, predicting 10 745 repeat structures. In all, 2797 structures were classified according to a recently proposed classification schema, which was expanded to accommodate new findings. In addition, detailed annotations were performed in a subset of 321 proteins. These annotations feature information on start and end positions for the repeat regions and units. RepeatsDB is an ongoing effort to systematically classify and annotate structural protein repeats in a consistent way. It provides users with the possibility to access and download high-quality datasets either interactively or programmatically through web services. PMID:24311564

  14. Electrocatalytic H2 production with a turnover frequency >107 s-1: the medium provides an increase in rate but not overpotential

    SciTech Connect

    Hou, Jianbo; Fang, Ming; Cardenas, Allan Jay P.; Shaw, Wendy J.; Helm, Monte L.; Bullock, R. Morris; Roberts, John A. S.; O'Hagan, Molly

    2014-01-01

    In this paper, rapid proton movement results in exceptionally fast electrocatalytic H2 production (up to 3 × 107 s-1) at overpotentials of ~400 mV when catalysed by [Ni(PPh2NC6H4x2)2]2+ complexes in an acidic ionic liquid–water medium ([(DMF)H]NTf2–H2O, χH2O = 0.71).

  15. Learning with repeated-game strategies.

    PubMed

    Ioannou, Christos A; Romero, Julian

    2014-01-01

    We use the self-tuning Experience Weighted Attraction model with repeated-game strategies as a computer testbed to examine the relative frequency, speed of convergence and progression of a set of repeated-game strategies in four symmetric 2 × 2 games: Prisoner's Dilemma, Battle of the Sexes, Stag-Hunt, and Chicken. In the Prisoner's Dilemma game, we find that the strategy with the most occurrences is the "Grim-Trigger." In the Battle of the Sexes game, a cooperative pair that alternates between the two pure-strategy Nash equilibria emerges as the one with the most occurrences. In the Stag-Hunt and Chicken games, the "Win-Stay, Lose-Shift" and "Grim-Trigger" strategies are the ones with the most occurrences. Overall, the pairs that converged quickly ended up at the cooperative outcomes, whereas the ones that were extremely slow to reach convergence ended up at non-cooperative outcomes. PMID:25126053

  16. Saturation of repeated quantum measurements

    NASA Astrophysics Data System (ADS)

    Haapasalo, Erkka; Heinosaari, Teiko; Kuramochi, Yui

    2016-08-01

    We study sequential measurement scenarios where the system is repeatedly subjected to the same measurement process. We first provide examples of such repeated measurements where further repetitions of the measurement do not increase our knowledge on the system after some finite number of measurement steps. We also prove, however, that repeating the Lüders measurement of an unsharp two-outcome observable never saturates in this sense, and we characterize the observable measured in the limit of infinitely many repetitions. Our result implies that a repeated measurement can be used to correct the inherent noise of an unsharp observable.

  17. To Repeat or Not to Repeat a Course

    ERIC Educational Resources Information Center

    Armstrong, Michael J.; Biktimirov, Ernest N.

    2013-01-01

    The difficult transition from high school to university means that many students need to repeat (retake) 1 or more of their university courses. The authors examine the performance of students repeating first-year core courses in an undergraduate business program. They used data from university records for 116 students who took a total of 232…

  18. DWI Repeaters and Non-Repeaters: A Comparison.

    ERIC Educational Resources Information Center

    Weeber, Stan

    1981-01-01

    Discussed how driving-while-intoxicated (DWI) repeaters differed signigicantly from nonrepeaters on 4 of 23 variables tested. Repeaters were more likely to have zero or two dependent children, attend church frequently, drink occasionally and have one or more arrests for public intoxication. (Author)

  19. Photonic-resonant left-handed medium

    NASA Astrophysics Data System (ADS)

    Shen, Jian Qi

    2006-08-01

    A new scheme to realize simultaneously negative permittivity and permeability in a coherent atomic vapor medium (photonic-resonant material) via a coherent driving mechanism is suggested. It is verified that the atomic system coherently driven by a strong optical field will give rise to a negative refractive index in certain probe frequency ranges. One of the most remarkable features of the present scheme is such that a slab fabricated by the left-handed vapor medium is an ideal candidate for designing perfect lenses since the photonic-resonant atomic vapor cannot only exhibit an isotropic negative refractive index, but also provide a good impedance match at the air-medium interfaces.

  20. Dual frequency optical cavity

    DOEpatents

    George, E.V.; Schipper, J.F.

    Method and apparatus for generating two distinct laser frequencies in an optical cavity, using a T configuration laser cavity and means for intermittently increasing or decreasing the index of refraction n of an associated transmission medium in one arm of the optical cavity to enhance laser action in one arm or the second arm of the cavity.

  1. Dual frequency optical cavity

    DOEpatents

    George, E. Victor; Schipper, John F.

    1985-01-01

    Method and apparatus for generating two distinct laser frequencies in an optical cavity, using a "T" configuration laser cavity and means for intermittently increasing or decreasing the index of refraction n of an associated transmission medium in one arm of the optical cavity to enhance laser action in one arm or the second arm of the cavity.

  2. Study of repeater technology for advanced multifunctional communications satellites

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Investigations are presented concerning design concepts and implementation approaches for the satellite communication repeater subsystems of advanced multifunctional satellites. In such systems the important concepts are the use of multiple antenna beams, repeater switching (routing), and efficient spectrum utilization through frequency reuse. An information base on these techniques was developed and tradeoff analyses were made of repeater design concepts, with the work design taken in a broad sense to include modulation beam coverage patterns. There were five major areas of study: requirements analysis and processing; study of interbeam interference in multibeam systems; characterization of multiple-beam switching repeaters; estimation of repeater weight and power for a number of alternatives; and tradeoff analyses based on these weight and power data.

  3. Nifty Nines and Repeating Decimals

    ERIC Educational Resources Information Center

    Brown, Scott A.

    2016-01-01

    The traditional technique for converting repeating decimals to common fractions can be found in nearly every algebra textbook that has been published, as well as in many precalculus texts. However, students generally encounter repeating decimal numerals earlier than high school when they study rational numbers in prealgebra classes. Therefore, how…

  4. Estimating repeatability of egg size

    USGS Publications Warehouse

    Flint, P.L.; Rockwell, R.F.; Sedinger, J.S.

    2001-01-01

    Measures of repeatability have long been used to assess patterns of variation in egg size within and among females. We compared different analytical approaches for estimating repeatability of egg size of Black Brant. Separate estimates of repeatability for eggs of each clutch size and laying sequence number varied from 0.49 to 0.64. We suggest that using the averaging egg size within clutches results in underestimation of variation within females and thereby overestimates repeatability. We recommend a nested design that partitions egg-size variation within clutches, among clutches within females, and among females. We demonstrate little variation in estimates of repeatability resulting from a nested model controlling for egg laying sequence and a nested model in which we assumed laying sequence was unknown.

  5. Repeating Jansky's Experiment

    NASA Astrophysics Data System (ADS)

    Ghigo, F.; Balser, D.; Bates, N.; Grammer, W.; Heatherly, S.; Langston, G.; Emerson, D.

    1996-05-01

    A replica of Karl Jansky's "merry-go-round" antenna at the National Radio Astronomy Observatory in Green Bank, West Virginia is being refurbished to make it a usable radio telescope. Although receiver and data acquisition systems have been added which are more modern than Jansky's, the antenna itself including the feed and drive system are very similar to those used by Jansky. The antenna is capable of mapping the whole accessible sky every day with a 25 degree beam at 20 MHz. Since very little wide field mapping has been done at this frequency since Jansky's day, it is potentially interesting to look for possible changes that may have happened in the past 60+ years to the flux densities of the brightest sources and the galactic emission. These observations take advantage of the current solar minimum, during which 20 MHz observing is often possible. When the refurbishment project is complete, the antenna may be used on a continuing basis for student projects in NRAO-hosted education programs. The progress to date on this project will be summarized, and preliminary observations will be presented.

  6. Acoustic Waves Generated by Impulsive Disturbances in a Gravitationally Stratified Medium

    NASA Astrophysics Data System (ADS)

    Chae, Jongchul; Goode, Philip R.

    2015-08-01

    Even though it is well-known from observations of the Sun that three-minute period chromospheric oscillations persist in the internetwork quiet regions and sunspot umbrae, until now their origin and persistence has defied clear explanation. Here we provide a clear and simple explanation for it with a demonstration of how such oscillations at the chromosphere's cutoff frequency naturally arise in a gravitationally stratified medium when it is disturbed. The largest-wavenumber vertical components of a chromospheric disturbance produce the highest-frequency wave packets, which propagate out of the disturbed region at group speeds that are close to the sound speed. Meanwhile, the smallest-wavenumber components develop into wave packets of frequencies close to the acoustic cutoff frequency that propagate at group speeds that are much lower than the sound speed. Because of their low propagation speed, these low-frequency wave packets linger in the disturbed region and nearby, and thus, are the ones that an observer would identify as the persistent, chromospheric three-minute oscillations. We emphasize that we can account for the power of the persistent chromospheric oscillations as coming from the repeated occurrence of disturbances with length scales greater than twice the pressure scale height in the upper photosphere.

  7. ACOUSTIC WAVES GENERATED BY IMPULSIVE DISTURBANCES IN A GRAVITATIONALLY STRATIFIED MEDIUM

    SciTech Connect

    Chae, Jongchul; Goode, Philip R.

    2015-08-01

    Even though it is well-known from observations of the Sun that three-minute period chromospheric oscillations persist in the internetwork quiet regions and sunspot umbrae, until now their origin and persistence has defied clear explanation. Here we provide a clear and simple explanation for it with a demonstration of how such oscillations at the chromosphere's cutoff frequency naturally arise in a gravitationally stratified medium when it is disturbed. The largest-wavenumber vertical components of a chromospheric disturbance produce the highest-frequency wave packets, which propagate out of the disturbed region at group speeds that are close to the sound speed. Meanwhile, the smallest-wavenumber components develop into wave packets of frequencies close to the acoustic cutoff frequency that propagate at group speeds that are much lower than the sound speed. Because of their low propagation speed, these low-frequency wave packets linger in the disturbed region and nearby, and thus, are the ones that an observer would identify as the persistent, chromospheric three-minute oscillations. We emphasize that we can account for the power of the persistent chromospheric oscillations as coming from the repeated occurrence of disturbances with length scales greater than twice the pressure scale height in the upper photosphere.

  8. Synthetic laser medium

    DOEpatents

    Stokowski, Stanley E.

    1989-01-01

    A laser medium is particularly useful in high average power solid state lasers. The laser medium includes a chormium dopant and preferably neodymium ions as codopant, and is primarily a gadolinium scandium gallium garnet, or an analog thereof. Divalent cations inhibit spiral morphology as large boules from which the laser medium is derived are grown, and a source of ions convertible between a trivalent state and a tetravalent state at a low ionization energy are in the laser medium to reduce an absorption coefficient at about one micron wavelength otherwise caused by the divalent cations. These divalent cations and convertible ions are dispersed in the laser medium. Preferred convertible ions are provided from titanium or cerium sources.

  9. Synthetic laser medium

    DOEpatents

    Stokowski, S.E.

    1987-10-20

    A laser medium is particularly useful in high average power solid state lasers. The laser medium includes a chromium dopant and preferably neodymium ions as codopant, and is primarily a gadolinium scandium gallium garnet, or an analog thereof. Divalent cations inhibit spiral morphology as large boules from which the laser medium is derived are grown, and a source of ions convertible between a trivalent state and a tetravalent state at a low ionization energy are in the laser medium to reduce an absorption coefficient at about one micron wavelength otherwise caused by the divalent cations. These divalent cations and convertible ions are dispersed in the laser medium. Preferred convertible ions are provided from titanium or cerium sources.

  10. Protein Repeats from First Principles.

    PubMed

    Turjanski, Pablo; Parra, R Gonzalo; Espada, Rocío; Becher, Verónica; Ferreiro, Diego U

    2016-01-01

    Some natural proteins display recurrent structural patterns. Despite being highly similar at the tertiary structure level, repeating patterns within a single repeat protein can be extremely variable at the sequence level. We use a mathematical definition of a repetition and investigate the occurrences of these in sequences of different protein families. We found that long stretches of perfect repetitions are infrequent in individual natural proteins, even for those which are known to fold into structures of recurrent structural motifs. We found that natural repeat proteins are indeed repetitive in their families, exhibiting abundant stretches of 6 amino acids or longer that are perfect repetitions in the reference family. We provide a systematic quantification for this repetitiveness. We show that this form of repetitiveness is not exclusive of repeat proteins, but also occurs in globular domains. A by-product of this work is a fast quantification of the likelihood of a protein to belong to a family. PMID:27044676

  11. Protein Repeats from First Principles.

    PubMed

    Turjanski, Pablo; Parra, R Gonzalo; Espada, Rocío; Becher, Verónica; Ferreiro, Diego U

    2016-04-05

    Some natural proteins display recurrent structural patterns. Despite being highly similar at the tertiary structure level, repeating patterns within a single repeat protein can be extremely variable at the sequence level. We use a mathematical definition of a repetition and investigate the occurrences of these in sequences of different protein families. We found that long stretches of perfect repetitions are infrequent in individual natural proteins, even for those which are known to fold into structures of recurrent structural motifs. We found that natural repeat proteins are indeed repetitive in their families, exhibiting abundant stretches of 6 amino acids or longer that are perfect repetitions in the reference family. We provide a systematic quantification for this repetitiveness. We show that this form of repetitiveness is not exclusive of repeat proteins, but also occurs in globular domains. A by-product of this work is a fast quantification of the likelihood of a protein to belong to a family.

  12. Protein Repeats from First Principles

    PubMed Central

    Turjanski, Pablo; Parra, R. Gonzalo; Espada, Rocío; Becher, Verónica; Ferreiro, Diego U.

    2016-01-01

    Some natural proteins display recurrent structural patterns. Despite being highly similar at the tertiary structure level, repeating patterns within a single repeat protein can be extremely variable at the sequence level. We use a mathematical definition of a repetition and investigate the occurrences of these in sequences of different protein families. We found that long stretches of perfect repetitions are infrequent in individual natural proteins, even for those which are known to fold into structures of recurrent structural motifs. We found that natural repeat proteins are indeed repetitive in their families, exhibiting abundant stretches of 6 amino acids or longer that are perfect repetitions in the reference family. We provide a systematic quantification for this repetitiveness. We show that this form of repetitiveness is not exclusive of repeat proteins, but also occurs in globular domains. A by-product of this work is a fast quantification of the likelihood of a protein to belong to a family. PMID:27044676

  13. Analysis of Laboratory Repeat Critical Values at a Large Tertiary Teaching Hospital in China

    PubMed Central

    Yang, Dagan; Zhou, Yunxian; Yang, Chunwei

    2013-01-01

    Context As a patient safety measure, laboratories are required to have a critical values policy by regulatory agencies. Unfortunately, little information is available on repeat critical values for the same analyte(s) on the same patient. Objective To investigate the occurrence and distribution of repeat critical values and the relationship between the frequency of such values and patient outcome to provide information for hospitals on improving reporting policies. Methods Eleven laboratory critical value lists, including chemistry and hematology analytes, were selected from a tertiary hospital in China in the year 2010. The distribution and interval time for each repeat critical value were calculated. Serum potassium and platelet count were used as examples to illustrate the relationship between the frequency of the repeat critical values and patient outcome. Results All test items on the critical value list were prone to the occurrence of repeat critical values. On average, each patient who experienced critical values had 2.10 occurrences. The median interval time for each repeat critical value varied, with most being longer than 8 hours. For those patients who had repeat critical values of serum potassium and platelet count, along with the increased frequency, the patients had a longer hospital stay and a generally worse outcome. Conclusions Patient can have a number of repeat critical values and the frequency of these values is closely related to patient outcome. A careful evaluation is warranted if a laboratory chooses to adopt a policy of not reporting each repeat critical value. PMID:23516637

  14. Limitations on quantum key repeaters.

    PubMed

    Bäuml, Stefan; Christandl, Matthias; Horodecki, Karol; Winter, Andreas

    2015-04-23

    A major application of quantum communication is the distribution of entangled particles for use in quantum key distribution. Owing to noise in the communication line, quantum key distribution is, in practice, limited to a distance of a few hundred kilometres, and can only be extended to longer distances by use of a quantum repeater, a device that performs entanglement distillation and quantum teleportation. The existence of noisy entangled states that are undistillable but nevertheless useful for quantum key distribution raises the question of the feasibility of a quantum key repeater, which would work beyond the limits of entanglement distillation, hence possibly tolerating higher noise levels than existing protocols. Here we exhibit fundamental limits on such a device in the form of bounds on the rate at which it may extract secure key. As a consequence, we give examples of states suitable for quantum key distribution but unsuitable for the most general quantum key repeater protocol.

  15. Limitations on quantum key repeaters.

    PubMed

    Bäuml, Stefan; Christandl, Matthias; Horodecki, Karol; Winter, Andreas

    2015-01-01

    A major application of quantum communication is the distribution of entangled particles for use in quantum key distribution. Owing to noise in the communication line, quantum key distribution is, in practice, limited to a distance of a few hundred kilometres, and can only be extended to longer distances by use of a quantum repeater, a device that performs entanglement distillation and quantum teleportation. The existence of noisy entangled states that are undistillable but nevertheless useful for quantum key distribution raises the question of the feasibility of a quantum key repeater, which would work beyond the limits of entanglement distillation, hence possibly tolerating higher noise levels than existing protocols. Here we exhibit fundamental limits on such a device in the form of bounds on the rate at which it may extract secure key. As a consequence, we give examples of states suitable for quantum key distribution but unsuitable for the most general quantum key repeater protocol. PMID:25903096

  16. Repeated observation of an uncertain signal. [sensory adaptation

    NASA Technical Reports Server (NTRS)

    Swets, J. A.; Birdsall, T. G.

    1978-01-01

    The focus here is on sensory adaptation, or progressively more appropriate attention, as repeated observations yield more information about a signal with an uncertain parameter. The signal was a brief sinusoid; its uncertain parameter was frequency. Detection performance is predicted from data on a signal of known and constant frequency, as a function of the number of frequencies the uncertain signal could assume. A comparison condition presented a signal that varied in a manner not permitting adaptation. Models derived from signal detection theory describe the ideal observation processes for the three signal conditions, and supply quantitative predictions of relative performances. The models are generally supported by the data.

  17. High-Speed Digital Signal Processing Method for Detection of Repeating Earthquakes Using GPGPU-Acceleration

    NASA Astrophysics Data System (ADS)

    Kawakami, Taiki; Okubo, Kan; Uchida, Naoki; Takeuchi, Nobunao; Matsuzawa, Toru

    2013-04-01

    Repeating earthquakes are occurring on the similar asperity at the plate boundary. These earthquakes have an important property; the seismic waveforms observed at the identical observation site are very similar regardless of their occurrence time. The slip histories of repeating earthquakes could reveal the existence of asperities: The Analysis of repeating earthquakes can detect the characteristics of the asperities and realize the temporal and spatial monitoring of the slip in the plate boundary. Moreover, we are expecting the medium-term predictions of earthquake at the plate boundary by means of analysis of repeating earthquakes. Although the previous works mostly clarified the existence of asperity and repeating earthquake, and relationship between asperity and quasi-static slip area, the stable and robust method for automatic detection of repeating earthquakes has not been established yet. Furthermore, in order to process the enormous data (so-called big data) the speedup of the signal processing is an important issue. Recently, GPU (Graphic Processing Unit) is used as an acceleration tool for the signal processing in various study fields. This movement is called GPGPU (General Purpose computing on GPUs). In the last few years the performance of GPU keeps on improving rapidly. That is, a PC (personal computer) with GPUs might be a personal supercomputer. GPU computing gives us the high-performance computing environment at a lower cost than before. Therefore, the use of GPUs contributes to a significant reduction of the execution time in signal processing of the huge seismic data. In this study, first, we applied the band-limited Fourier phase correlation as a fast method of detecting repeating earthquake. This method utilizes only band-limited phase information and yields the correlation values between two seismic signals. Secondly, we employ coherence function using three orthogonal components (East-West, North-South, and Up-Down) of seismic data as a

  18. Gravitational lensing in plasmic medium

    SciTech Connect

    Bisnovatyi-Kogan, G. S. Tsupko, O. Yu.

    2015-07-15

    The influence of plasma on different effects of gravitational lensing is reviewed. Using the Hamiltonian approach for geometrical optics in a medium in the presence of gravity, an exact formula for the photon deflection angle by a black hole (or another body with a Schwarzschild metric) embedded in plasma with a spherically symmetric density distribution is derived. The deflection angle in this case is determined by the mutual combination of different factors: gravity, dispersion, and refraction. While the effects of deflection by the gravity in vacuum and the refractive deflection in a nonhomogeneous medium are well known, the new effect is that, in the case of a homogeneous plasma, in the absence of refractive deflection, the gravitational deflection differs from the vacuum deflection and depends on the photon frequency. In the presence of a plasma nonhomogeneity, the chromatic refractive deflection also occurs, so the presence of plasma always makes gravitational lensing chromatic. In particular, the presence of plasma leads to different angular positions of the same image if it is observed at different wavelengths. It is discussed in detail how to apply the presented formulas for the calculation of the deflection angle in different situations. Gravitational lensing in plasma beyond the weak deflection approximation is also considered.

  19. Gravitational lensing in plasmic medium

    NASA Astrophysics Data System (ADS)

    Bisnovatyi-Kogan, G. S.; Tsupko, O. Yu.

    2015-07-01

    The influence of plasma on different effects of gravitational lensing is reviewed. Using the Hamiltonian approach for geometrical optics in a medium in the presence of gravity, an exact formula for the photon deflection angle by a black hole (or another body with a Schwarzschild metric) embedded in plasma with a spherically symmetric density distribution is derived. The deflection angle in this case is determined by the mutual combination of different factors: gravity, dispersion, and refraction. While the effects of deflection by the gravity in vacuum and the refractive deflection in a nonhomogeneous medium are well known, the new effect is that, in the case of a homogeneous plasma, in the absence of refractive deflection, the gravitational deflection differs from the vacuum deflection and depends on the photon frequency. In the presence of a plasma nonhomogeneity, the chromatic refractive deflection also occurs, so the presence of plasma always makes gravitational lensing chromatic. In particular, the presence of plasma leads to different angular positions of the same image if it is observed at different wavelengths. It is discussed in detail how to apply the presented formulas for the calculation of the deflection angle in different situations. Gravitational lensing in plasma beyond the weak deflection approximation is also considered.

  20. Repeated static contractions increase mitochondrial vulnerability toward oxidative stress in human skeletal muscle.

    PubMed

    Sahlin, Kent; Nielsen, Jens Steen; Mogensen, Martin; Tonkonogi, Michail

    2006-09-01

    Repeated static contractions (RSC) induce large fluctuations in tissue oxygen tension and increase the generation of reactive oxygen species (ROS). This study investigated the effect of RSC on muscle contractility, mitochondrial respiratory function, and in vitro sarcoplasmic reticulum (SR) Ca(2+) kinetics in human muscle. Ten male subjects performed five bouts of static knee extension with 10-min rest in between. Each bout of RSC (target torque 66% of maximal voluntary contraction torque) was maintained to fatigue. Muscle biopsies were taken preexercise and 0.3 and 24 h postexercise from vastus lateralis. Mitochondria were isolated and respiratory function measured after incubation with H(2)O(2) (HPX) or control medium (Con). Mitochondrial function was not affected by RSC during Con. However, RSC exacerbated mitochondrial dysfunction during HPX, resulting in decreased respiratory control index, decreased mitochondrial efficiency (phosphorylated ADP-to-oxygen consumed ratio), and increased noncoupled respiration (HPX/Con post- vs. preexercise). SR Ca(2+) uptake rate was lower 0.3 vs. 24 h postexercise, whereas SR Ca(2+) release rate was unchanged. RSC resulted in long-lasting changes in muscle contractility, including reduced maximal torque, low-frequency fatigue, and faster torque relaxation. It is concluded that RSC increases mitochondrial vulnerability toward ROS, reduces SR Ca(2+) uptake rate, and causes low-frequency fatigue. Although conclusive evidence is lacking, we suggest that these changes are related to increased formation of ROS during RSC. PMID:16728514

  1. [Prolonging the vase life of carnation "Mabel" through integrating repeated ACC oxidase genes into its genome].

    PubMed

    Yu, Yi-Xun; Bao, Man-Zhu

    2004-10-01

    Carnation (Dianthus caryophyllus L.) is one of the most important cut flowers. The cultivar "Mabel" of carnation was transformed with direct repeat gene of ACC oxidase, the key enzyme in ethylene synthesis, driven by the CaMV35S promoter mediated by Agrobacterium tumefacien. Hygromycin phosphotransferase (HPT) gene was used as selection marker. Leaf explants were pre-cultured on shoot-inducing medium for 2 d, then immersed in Agrobacterium suspension for 8-12 min. Co-cultivation was carried out on the medium (MS+BA 1.0 mg/L+NAA 0.3 mg/L +Acetosyringone 100 micromol/L, pH 5.8-6.0) for 3 d. After that transformants were obtained by transferring explants to selection medium supplemented with 5 mg/L hygromycin (Hyg) and 400 mg/L cefotaxime (Cef). Southern blotting detection showed that a foreign gene was integrated into the carnation genome and 3 transgenic lines (T257, T299 and T273 line) obtained. Addition of acetosyringone and the time of co-culture were the main factors that influenced transformation frequency. After being transplanted to soil, transgenic plants were grew normally in greenhouse. Ethylene production of cut flower of transgenic T257 line was 95% lower than that of the control, and that of T299 line was reduced by 90% than that of the control, while that of transgenic T273 line has no of significantly different from control. Vase life of transgenic T257 line was 5 d longer than that of the control line at 25 degrees C.

  2. Learning with repeated-game strategies

    PubMed Central

    Ioannou, Christos A.; Romero, Julian

    2014-01-01

    We use the self-tuning Experience Weighted Attraction model with repeated-game strategies as a computer testbed to examine the relative frequency, speed of convergence and progression of a set of repeated-game strategies in four symmetric 2 × 2 games: Prisoner's Dilemma, Battle of the Sexes, Stag-Hunt, and Chicken. In the Prisoner's Dilemma game, we find that the strategy with the most occurrences is the “Grim-Trigger.” In the Battle of the Sexes game, a cooperative pair that alternates between the two pure-strategy Nash equilibria emerges as the one with the most occurrences. In the Stag-Hunt and Chicken games, the “Win-Stay, Lose-Shift” and “Grim-Trigger” strategies are the ones with the most occurrences. Overall, the pairs that converged quickly ended up at the cooperative outcomes, whereas the ones that were extremely slow to reach convergence ended up at non-cooperative outcomes. PMID:25126053

  3. Do Twelfths Terminate or Repeat?

    ERIC Educational Resources Information Center

    Ambrose, Rebecca; Burnison, Erica

    2015-01-01

    When finding the decimal equivalent of a fraction with 12 in the denominator, will it terminate or repeat? This question came from a seventh grader in author Erica Burnison's class as the student was pondering a poster generated by one of her classmates. Not only was the question intriguing, but it also affirmed the belief in the power of…

  4. Repeat Pregnancies among Adolescent Mothers.

    ERIC Educational Resources Information Center

    Gillmore, Mary Rogers; Lewis, Steven M.; Lohr, Mary Jane; Spencer, Michael S.; White, Rachelle D.

    1997-01-01

    Reports the results of an event history analysis of rapidly repeated pregnancies among a sample of 170 adolescents. Results show that the best fitting model for these girls included two proximate determinants of pregnancy, contraceptive use, and other factors. Findings indicate that such pregnancies among teenagers are somewhat predictable. (RJM)

  5. Pentapeptide Repeat Proteins and Cyanobacteria

    SciTech Connect

    Buchko, Garry W.

    2009-10-16

    Cyanobacteria are unique in many ways and one unusual feature is the presence of a suite of proteins that contain at least one domain with a minimum of eight tandem repeated five-residues (Rfr) of the general consensus sequence A[N/D]LXX. The function of such pentapeptide repeat proteins (PRPs) are still unknown, however, their prevalence in cyanobacteria suggests that they may play some role in the unique biological activities of cyanobacteria. As part of an inter-disciplinary Membrane Biology Grand Challenge at the Environmental Molecular Sciences Laboratory (Pacific Northwest National Laboratory) and Washington University in St. Louis, the genome of Cyanothece 51142 was sequenced and its molecular biology studied with relation to circadian rhythms. The genome of Cyanothece encodes for 35 proteins that contain at least one PRP domain. These proteins range in size from 105 (Cce_3102) to 930 (Cce_2929) kDa with the PRP domains ranging in predicted size from 12 (Cce_1545) to 62 (cce_3979) tandem pentapeptide repeats. Transcriptomic studies with 29 out of the 35 genes showed that at least three of the PRPs in Cyanothece 51142 (cce_0029, cce_3083, and cce_3272) oscillated with repeated periods of light and dark, further supporting a biological function for PRPs. Using X-ray diffraction crystallography, the structure for two pentapeptide repeat proteins from Cyanothece 51142 were determined, cce_1272 (aka Rfr32) and cce_4529 (aka Rfr23). Analysis of their molecular structures suggests that all PRP may share the same structural motif, a novel type of right-handed quadrilateral β-helix, or Rfr-fold, reminiscent of a square tower with four distinct faces. Each pentapeptide repeat occupies one face of the Rfr-fold with four consecutive pentapeptide repeats completing a coil that, in turn, stack upon each other to form “protein skyscrapers”. Details of the structural features of the Rfr-fold are reviewed here together with a discussion for the possible role of end

  6. Hypermedia as medium

    NASA Technical Reports Server (NTRS)

    Dede, Christopher J.

    1990-01-01

    Claims and rebuttals that hypermedia (the associative, nonlinear interconnection of multimedia materials) is a fundamentally innovative means of thinking and communicating are described. This representational architecture has many advantages that make it a major advance over other media; however, it also has several intrinsic problems that severly limits its effectiveness as a medium. These advantages and limits in applications are discussed.

  7. Holographic recording medium

    NASA Technical Reports Server (NTRS)

    Gange, Robert Allen (Inventor)

    1977-01-01

    A holographic recording medium comprising a conductive substrate, a photoconductive layer and an electrically alterable layer of a linear, low molecular weight hydrocarbon polymer has improved fatigue resistance. An acrylic barrier layer can be interposed between the photoconductive and electrically alterable layers.

  8. Are major repeater patients addicted to suicidal behavior?

    PubMed

    Blasco-Fontecilla, Hilario; Artieda-Urrutia, Paula; Berenguer-Elias, Nuria; Garcia-Vega, Juan Manuel; Fernandez-Rodriguez, Monica; Rodriguez-Lomas, Cesar; Gonzalez-Villalobos, Isabel; Iruela-Cuadrado, Luis; de Leon, José

    2014-01-01

    The literature provides support for the hypothesis that some major repeaters (individuals with >=5 lifetime suicide attempts) are addicted to suicidal behavior (SB). This study explores whether major repeaters are addicted to SB or not using 7 criteria: tolerance (Criterion 1), withdrawal (Criterion 2), loss of control (Criterion 3), problems in quitting/cutting down (Criterion 4), much time spent using (Criterion 5), substantial reduction in activities (Criterion 6), and adverse physiological/physical consequences (Criterion 7). Total dependence on SB was indicated by the presence of 3 or more of the 7 criteria in the last 12 months. This cross-sectional study at Puerta de Hierro University Hospital (Madrid, Spain) recruited 118 suicide attempters including 8 major repeaters (7%, 8/118), who were all females. The association between each SB addiction criterion, physiological dependence and total dependence with major repeater status was tested for significance and for effect size with odds ratios (ORs) and their 95% confidence intervals. As hypothesized, major repeaters met significantly higher frequency of criteria for total dependence on SB, OR=62.9 (6.4-615). A backward stepwise logistic regression model was used to provide an OR between major repeater status and total dependence status corrected by confounding variables. Age, panic disorder without agoraphobia, borderline personality disorder, history of psychiatric inpatient admission, and total dependence on SB were introduced as independent variables with major repeater status as the dependent variable. The model selected total dependence and age as the remaining significant variables in the last step. Accordingly, major repeaters appear to be addicted to SB. PMID:25580865

  9. Are major repeater patients addicted to suicidal behavior?

    PubMed

    Blasco-Fontecilla, Hilario; Artieda-Urrutia, Paula; Berenguer-Elias, Nuria; Garcia-Vega, Juan Manuel; Fernandez-Rodriguez, Monica; Rodriguez-Lomas, Cesar; Gonzalez-Villalobos, Isabel; Iruela-Cuadrado, Luis; de Leon, José

    2014-01-01

    The literature provides support for the hypothesis that some major repeaters (individuals with >=5 lifetime suicide attempts) are addicted to suicidal behavior (SB). This study explores whether major repeaters are addicted to SB or not using 7 criteria: tolerance (Criterion 1), withdrawal (Criterion 2), loss of control (Criterion 3), problems in quitting/cutting down (Criterion 4), much time spent using (Criterion 5), substantial reduction in activities (Criterion 6), and adverse physiological/physical consequences (Criterion 7). Total dependence on SB was indicated by the presence of 3 or more of the 7 criteria in the last 12 months. This cross-sectional study at Puerta de Hierro University Hospital (Madrid, Spain) recruited 118 suicide attempters including 8 major repeaters (7%, 8/118), who were all females. The association between each SB addiction criterion, physiological dependence and total dependence with major repeater status was tested for significance and for effect size with odds ratios (ORs) and their 95% confidence intervals. As hypothesized, major repeaters met significantly higher frequency of criteria for total dependence on SB, OR=62.9 (6.4-615). A backward stepwise logistic regression model was used to provide an OR between major repeater status and total dependence status corrected by confounding variables. Age, panic disorder without agoraphobia, borderline personality disorder, history of psychiatric inpatient admission, and total dependence on SB were introduced as independent variables with major repeater status as the dependent variable. The model selected total dependence and age as the remaining significant variables in the last step. Accordingly, major repeaters appear to be addicted to SB.

  10. Directionality switchable gain stabilized linear repeater

    NASA Astrophysics Data System (ADS)

    Ota, Takayuki; Ohmachi, Tadashi; Aida, Kazuo

    2004-10-01

    We propose a new approach to realize a bidirectional linear repeater suitable for future optical internet networks and fault location in repeater chain with OTDR. The proposed approach is the linear repeater of simple configuration whose directionality is rearranged dynamically by electrical control signal. The repeater is composed of a magneto-optical switch, a circulator, a dynamically gain stabilized unidirectional EDFA, and control circuits. The repeater directionality is rearranged as fast as 0.1ms by an electrical control pulse. It is experimentally confirmed that OTDR with the directionality switchable repeater is feasible for repeater chain. The detailed design and performance of the repeater are also discussed, including the multi-pass interference (MPI) which may arise in the proposed repeater, the effect of the MPI on SNR degradation of the repeater chain and the feed-forward EDFA gain control circuit.

  11. Light beam frequency comb generator

    DOEpatents

    Priatko, G.J.; Kaskey, J.A.

    1992-11-24

    A light beam frequency comb generator uses an acousto-optic modulator to generate a plurality of light beams with frequencies which are uniformly separated and possess common noise and drift characteristics. A well collimated monochromatic input light beam is passed through this modulator to produce a set of both frequency shifted and unshifted optical beams. An optical system directs one or more frequency shifted beams along a path which is parallel to the path of the input light beam such that the frequency shifted beams are made incident on the modulator proximate to but separated from the point of incidence of the input light beam. After the beam is thus returned to and passed through the modulator repeatedly, a plurality of mutually parallel beams are generated which are frequency-shifted different numbers of times and possess common noise and drift characteristics. 2 figs.

  12. Light beam frequency comb generator

    DOEpatents

    Priatko, Gordon J.; Kaskey, Jeffrey A.

    1992-01-01

    A light beam frequency comb generator uses an acousto-optic modulator to generate a plurality of light beams with frequencies which are uniformly separated and possess common noise and drift characteristics. A well collimated monochromatic input light beam is passed through this modulator to produce a set of both frequency shifted and unshifted optical beams. An optical system directs one or more frequency shifted beams along a path which is parallel to the path of the input light beam such that the frequency shifted beams are made incident on the modulator proximate to but separated from the point of incidence of the input light beam. After the beam is thus returned to and passed through the modulator repeatedly, a plurality of mutually parallel beams are generated which are frequency-shifted different numbers of times and possess common noise and drift characteristics.

  13. Observations of Soft Gamma Repeaters

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2004-01-01

    Magnetars (Soft Gamma Repeaters and Anomalous X-ray Pulsars) are a subclass of neutron stars characterized by their recurrent X-ray bursts. While in an active (bursting) state (lasting anywhere between days and years), they are emit&ng hundreds of predominantly soft (kT=30 kev), short (0.1-100 ms long) events. Their quiescent source x-ray light ewes exhibit puhlions rotational period rate changes (spin-down) indicate that their magnetic fields are extremely high, of the order of 10^14- 10^l5 G. Such high B-field objects, dubbed "magnetars", had been predicted to exist in 1992, but the first concrete observational evidence were obtained in 1998 for two of these sources. I will discuss here the history of Soft Gamma Repeaters, and their spectral, timing and flux characteristics both in the persistent and their burst emission.

  14. A repeating fast radio burst.

    PubMed

    Spitler, L G; Scholz, P; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-03-10

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star. PMID:26934226

  15. A repeating fast radio burst.

    PubMed

    Spitler, L G; Scholz, P; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-03-10

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  16. A PLL Synthesizer with Learning Repeatable Fluctuation of Input Signal

    NASA Astrophysics Data System (ADS)

    Ono, Hiroyuki

    This paper describes a high frequency PLL (Phase Locked Loop) synthesizer with a function of learning then eliminating repeatable fluctuation of timing intervals on series input pulses. Typical spindle encoder generates digital pulses according to the revolution speed. The intervals of each pulse have repeatable fluctuation every revolution by eccentricity or warpage of the encoder scale disk. This method provides a programmable counter for the loop counter of PLL circuit and an interval counter with memory in order to learn the repeatable fluctuation. After the learning process, the PLL generates very pure tone clock signal based on the real flutter components of the spindle revolution speed without influenced by encoder errors. This method has been applied to a hard disk test system in order to generate 3GHz read/write clock.

  17. Liquid chromatographic extraction medium

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1994-01-01

    A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

  18. Liquid chromatographic extraction medium

    DOEpatents

    Horwitz, E.P.; Dietz, M.L.

    1994-09-13

    A method and apparatus are disclosed for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water. 1 fig.

  19. Genome nucleotide composition shapes variation in simple sequence repeats.

    PubMed

    Tian, Xiangjun; Strassmann, Joan E; Queller, David C

    2011-02-01

    Simple sequence repeats (SSRs) or microsatellites are a common component of genomes but vary greatly across species in their abundance. We tested the hypothesis that this variation is due in part to AT/GC content of genomes, with genomes biased toward either high AT or high CG generating more short random repeats that are long enough to enhance expansion through slippage during replication. To test this hypothesis, we identified repeats with perfect tandem iterations of 1-6 bp from 25 protists with complete or near-complete genome sequences. As expected, the density and the frequency are highly related to genome AT content, with excellent fits to quadratic regressions with minima near a 50% AT content and rising toward both extremes. Within species, the same trends hold, except the limited variation in AT content within each species places each mainly on the descending (GC rich), middle, or ascending (AT rich) part of the curve. The base usages of repeat motifs are also significantly correlated with genome nucleotide compositions: Percentages of AT-rich motifs rise with the increase of genome AT content but vice versa for GC-rich subgroups. Amino acid homopolymer repeats also show the expected quadratic relationship, with higher abundance in species with AT content biased in either direction. Our results show that genome nucleotide composition explains up to half of the variance in the abundance and motif constitution of SSRs.

  20. Polymorphism of CAG repeats in androgen receptor of carnivores.

    PubMed

    Wang, Qin; Zhang, Xiuyue; Wang, Xiaofang; Zeng, Bo; Jia, Xiaodong; Hou, Rong; Yue, Bisong

    2012-03-01

    Androgen effect is mediated by the androgen receptor (AR). The polymorphism of CAG triplet repeat (polyCAG), in the N-terminal transactivation domain of the AR protein, has been involved either in endocrine or neurological disorders in human. We obtained partial sequence of AR exon 1 in 10 carnivore species. In most carnivore species, polyglutamine length polymorphism presented in all three CAG repeat regions of AR, in contrast, only CAG-I site polymorphism presented in primate species, and CAG-I and CAG-III sites polymorphism presented in Canidae. Therefore, studies focusing on disease-associated polymorphism of poly(CAG) in carnivore species AR should investigate all three CAG repeats sites, and should not only consider CAG-I sites as the human disease studies. The trinucleotide repeat length in carnivore AR exon 1 had undergone from expansions to contractions during carnivores evolution, unlike a linear increase in primate species. Furthermore, the polymorphisms of the triplet-repeats in the same tissue (somatic mosaicism) were demonstrated in Moutain weasel, Eurasian lynx, Clouded leopard, Chinese tiger, Black leopard and Leopard AR. And, the abnormal stop codon was found in the exon 1 of three carnivore species AR (Moutain weasel, Eurasian lynx and Black leopard). It seemed to have a high frequency presence of tissue-specific somatic in carnivores AR genes. Thus the in vivo mechanism leading to such highly variable phenotypes of the described mutations, and their impact on these animals, are worthwhile to be further elucidated.

  1. Excision of plastid marker genes using directly repeated DNA sequences.

    PubMed

    Mudd, Elisabeth A; Madesis, Panagiotis; Avila, Elena Martin; Day, Anil

    2014-01-01

    Excision of marker genes using DNA direct repeats makes use of the predominant homologous recombination pathways present in the plastids of algae and plants. The method is simple, efficient, and widely applicable to plants and microalgae. Marker excision frequency is dependent on the length and number of directly repeated sequences. When two repeats are used a repeat size of greater than 600 bp promotes efficient excision of the marker gene. A wide variety of sequences can be used to make the direct repeats. Only a single round of transformation is required, and there is no requirement to introduce site-specific recombinases by retransformation or sexual crosses. Selection is used to maintain the marker and ensure homoplasmy of transgenic plastid genomes. Release of selection allows the accumulation of marker-free plastid genomes generated by marker excision, which is spontaneous, random, and a unidirectional process. Positive selection is provided by linking marker excision to restoration of the coding region of an herbicide resistance gene from two overlapping but incomplete coding regions. Cytoplasmic sorting allows the segregation of cells with marker-free transgenic plastids. The marker-free shoots resulting from direct repeat-mediated excision of marker genes have been isolated by vegetative propagation of shoots in the T0 generation. Alternatively, accumulation of marker-free plastid genomes during growth, development and flowering of T0 plants allows the collection of seeds that give rise to a high proportion of marker-free T1 seedlings. The simplicity and convenience of direct repeat excision facilitates its widespread use to isolate marker-free crops. PMID:24599849

  2. Repeated high-intensity exercise in professional rugby union.

    PubMed

    Austin, Damien; Gabbett, Tim; Jenkins, David

    2011-07-01

    The aim of the present study was to describe the frequency, duration, and nature of repeated high-intensity exercise in Super 14 rugby union. Time-motion analysis was used during seven competition matches over the 2008 and 2009 Super 14 seasons; five players from each of four positional groups (front row forwards, back row forwards, inside backs, and outside backs) were assessed (20 players in total). A repeated high-intensity exercise bout was considered to involve three or more sprints, and/or tackles and/or scrum/ruck/maul activities within 21 s during the same passage of play. The range of repeated high-intensity exercise bouts for each group in a match was as follows: 11-18 for front row forwards, 11-21 for back row forwards, 13-18 for inside backs, and 2-11 for outside backs. The durations of the most intense repeated high-intensity exercise bouts for each position ranged from 53 s to 165 s and the minimum recovery periods between repeated high-intensity exercise bouts ranged from 25 s for the back row forwards to 64 s for the front row forwards. The present results show that repeated high-intensity exercise bouts vary in duration and activities relative to position but all players in a game will average at least 10 changes in activity in the most demanding bouts and complete at least one tackle and two sprints. The most intense periods of activity are likely to last as long as 120 s and as little as 25 s recovery may separate consecutive repeated high-intensity exercise bouts. The present findings can be used by coaches to prepare their players for the most demanding passages of play likely to be experienced in elite rugby union. PMID:21756130

  3. Accumulate Repeat Accumulate Coded Modulation

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative coded modulation scheme called 'Accumulate Repeat Accumulate Coded Modulation' (ARA coded modulation). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes that are combined with high level modulation. Thus at the decoder belief propagation can be used for iterative decoding of ARA coded modulation on a graph, provided a demapper transforms the received in-phase and quadrature samples to reliability of the bits.

  4. Ring laser having an output at a single frequency

    DOEpatents

    Hackell, Lloyd A.

    1991-01-01

    A ring laser is disclosed that produces a single frequency of laser radiation in either the pulsed mode of operation or the continuous waveform (cw) mode of operation. The laser comprises a ring laser in a bowtie configuration, a birefringent gain material such as Nd:YLF, an improved optical diode that supports laser oscillation having a desired direction of travel and linear polarization, and a Q-switch. An output coupler (mirror) having a high reflectivity, such as 94%, is disclosed. Also disclosed is a self-seeded method of operation in which the laser can provide a pulse or a series of pulses of high power laser radiation at a consistent single frequency with a high degree of amplitude stability and temporal stability. In operation, the laser is operated in continuous waveform (cw) at a low power output with the Q-switch introducing a loss into the resonating cavity. Pumping is continued at a high level, causing the gain material to store energy. When a pulse is desired, the Q-switch is actuated to substantially reduce the losses so that a pulse can build up based on the low level cw oscillation. The pulse quickly builds, using the stored energy in the gain medium to provide a high power output pulse. The process may be repeated to provide a series of high power pulses of a consistent single frequency.

  5. The Local Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Ferlet, Roger

    Substantial progress in the field of the Local Interstellar Medium has been largely due to recent launches of space missions, mostly in the UV and X-ray domains, but also to ground-based observations, mainly in high resolution spectroscopy. However, a clear gap seems to remain between the wealth of new data and the theoretical understanding. This paper gives an overview of some observational aspects, with no attempt of completeness or doing justice to all the people involved in the field. As progress rarely evolves in straight paths, we can expect that our present picture of the solar system surroundings is not definitive.

  6. Medium wave exposure characterisation using exposure quotients.

    PubMed

    Paniagua, Jesús M; Rufo, Montaña; Jiménez, Antonio; Antolín, Alicia; Pinar, Iván

    2010-06-01

    One of the aspects considered in the International Commission on Non-Ionizing Radiation Protection guidelines is that, in situations of simultaneous exposure to fields of different frequencies, exposure quotients for thermal and electrical stimulation effects should be examined. The aim of the present work was to analyse the electromagnetic radiation levels and exposure quotients for exposure to multiple-frequency sources in the vicinity of medium wave radio broadcasting antennas. The measurements were made with a spectrum analyser and a monopole antenna. Kriging interpolation was used to prepare contour maps and to estimate the levels in the towns and villages of the zone. The results showed that the exposure quotient criterion based on electrical stimulation effects to be more stringent than those based on thermal effects or power density levels. Improvement of dosimetry evaluations requires the spectral components of the radiation to be quantified, followed by application of the criteria for exposure to multiple-frequency sources. PMID:20159912

  7. Medium wave exposure characterisation using exposure quotients.

    PubMed

    Paniagua, Jesús M; Rufo, Montaña; Jiménez, Antonio; Antolín, Alicia; Pinar, Iván

    2010-06-01

    One of the aspects considered in the International Commission on Non-Ionizing Radiation Protection guidelines is that, in situations of simultaneous exposure to fields of different frequencies, exposure quotients for thermal and electrical stimulation effects should be examined. The aim of the present work was to analyse the electromagnetic radiation levels and exposure quotients for exposure to multiple-frequency sources in the vicinity of medium wave radio broadcasting antennas. The measurements were made with a spectrum analyser and a monopole antenna. Kriging interpolation was used to prepare contour maps and to estimate the levels in the towns and villages of the zone. The results showed that the exposure quotient criterion based on electrical stimulation effects to be more stringent than those based on thermal effects or power density levels. Improvement of dosimetry evaluations requires the spectral components of the radiation to be quantified, followed by application of the criteria for exposure to multiple-frequency sources.

  8. Crowding by a repeating pattern.

    PubMed

    Rosen, Sarah; Pelli, Denis G

    2015-01-01

    Theinability to recognize a peripheral target among flankers is called crowding. For a foveal target, crowding can be distinguished from overlap masking by its sparing of detection, linear scaling with eccentricity, and invariance with target size.Crowding depends on the proximity and similarity of the flankers to the target. Flankers that are far from or dissimilar to the target do not crowd it. On a gray page, text whose neighboring letters have different colors, alternately black and white, has enough dissimilarity that it might escape crowding. Since reading speed is normally limited by crowding, escape from crowding should allow faster reading. Yet reading speed is unchanged (Chung & Mansfield, 2009). Why? A recent vernier study found that using alternating-color flankers produces strong crowding (Manassi, Sayim, & Herzog, 2012). Might that effect occur with letters and reading? Critical spacing is the minimum center-to-center target-flanker spacing needed to correctly identify the target. We measure it for a target letter surrounded by several equidistant flanker letters of the same polarity, opposite polarity, or mixed polarity: alternately white and black. We find strong crowding in the alternating condition, even though each flanker letter is beyond its own critical spacing (as measured in a separate condition). Thus a periodic repeating pattern can produce crowding even when the individual elements do not. Further, in all conditions we find that, once a periodic pattern repeats (two cycles), further repetition does not affect critical spacing of the innermost flanker.

  9. DENSE MEDIUM CYCLONE OPTIMIZATON

    SciTech Connect

    Gerald H. Luttrell; Chris J. Barbee; Peter J. Bethell; Chris J. Wood

    2005-06-30

    Dense medium cyclones (DMCs) are known to be efficient, high-tonnage devices suitable for upgrading particles in the 50 to 0.5 mm size range. This versatile separator, which uses centrifugal forces to enhance the separation of fine particles that cannot be upgraded in static dense medium separators, can be found in most modern coal plants and in a variety of mineral plants treating iron ore, dolomite, diamonds, potash and lead-zinc ores. Due to the high tonnage, a small increase in DMC efficiency can have a large impact on plant profitability. Unfortunately, the knowledge base required to properly design and operate DMCs has been seriously eroded during the past several decades. In an attempt to correct this problem, a set of engineering tools have been developed to allow producers to improve the efficiency of their DMC circuits. These tools include (1) low-cost density tracers that can be used by plant operators to rapidly assess DMC performance, (2) mathematical process models that can be used to predict the influence of changes in operating and design variables on DMC performance, and (3) an expert advisor system that provides plant operators with a user-friendly interface for evaluating, optimizing and trouble-shooting DMC circuits. The field data required to develop these tools was collected by conducting detailed sampling and evaluation programs at several industrial plant sites. These data were used to demonstrate the technical, economic and environmental benefits that can be realized through the application of these engineering tools.

  10. Migraine in the Emergency Department: a psychometric study of a migraine "repeaters" sample.

    PubMed

    Villani, Veronica; Bruti, Gianluca; Mostardini, Claudio; Di Stani, Fabrizio; Scattoni, Lorena; Dugoni, Demo; Vanacore, Nicola; Cerbo, Rosanna

    2005-09-01

    To evaluate the influence of psychometric variables on the "repeater" phenomenon in an emergency department, 15 "repeaters" and 27 outpatient migraineurs were recruited. All patients were submitted to the Beck Depression Inventory (BDI), State and Trait Anxiety Inventory, Toronto Alexithymia Scale-20 (TAS-20), Tridimensional Personality Questionnaire and Migraine DIsability Assessment Scale (MIDAS). The "repeater" group showed higher MIDAS total scores (p=0.02) and higher scores in TAS-20 (p=0.02) than the outpatients. A higher frequency of alexithymic trait (p=0.02) and higher BDI scores (p=0.07) have also been observed in the "repeater" group than the outpatients. Alexithymia and depressive mood associated with high disability may be a specific psychosocial pattern of "repeater" migraineurs. The psychometric evaluation of this population may be important to explain the "repeaters" phenomenon.

  11. Repeated Reading. What Works Clearinghouse Intervention Report

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2014

    2014-01-01

    "Repeated reading" is an academic practice that aims to increase oral reading fluency. "Repeated reading" can be used with students who have developed initial word reading skills but demonstrate inadequate reading fluency for their grade level. During "repeated reading," a student sits in a quiet location with a…

  12. 47 CFR 22.1015 - Repeater operation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Repeater operation. 22.1015 Section 22.1015... Offshore Radiotelephone Service § 22.1015 Repeater operation. Offshore central stations may be used as repeater stations provided that the licensee is able to maintain control of the station, and in...

  13. Frequency modulation drive for a piezoelectric motor

    DOEpatents

    Mittas, Anthony

    2001-01-01

    A piezoelectric motor has peak performance at a specific frequency f.sub.1 that may vary over a range of frequencies. A drive system is disclosed for operating such a motor at peak performance without feedback. The drive system consists of the motor and an ac source connected to power the motor, the ac source repeatedly generating a frequency over a range from f.sub.1 -.DELTA.x to f.sub.1 +.DELTA.y.

  14. Source Parameters for Repeating Earthquakes along the Middle America Trench

    NASA Astrophysics Data System (ADS)

    Bilek, S. L.; Phillips, W. S.; Walter, J. I.; Peng, Z.; Schwartz, S. Y.; Brudzinski, M. R.; Yao, D.

    2015-12-01

    Repeating earthquakes, with their similar locations and similar waveforms, are often thought to represent slip along the same patch of fault. Analysis of these earthquake clusters can provide useful information about the nature of the fault and earthquake interaction. Here we focus on sequences of repeating earthquakes along both the Nicoya Peninsula, Costa Rica and along the Oaxaca segment of Mexico, as both megathrust faults have been well instrumented in recent years with local seismic networks able to record the small magnitude earthquakes. These regions have also experienced large megathrust earthquakes as well as non-volcanic tremor and slow slip, suggesting a complex fault system that allows a wide spectrum of slip. We can use source characteristics of the repeating earthquakes to probe this fault complexity. Along the Nicoya Peninsula, there are over 370 repeating earthquakes (M 0.5-3.3) in the 3 months following the 2012 Mw 7.6 megathrust earthquake grouped into 55 distinct clusters. Along Oaxaca, the earthquake clusters or swarms (M 1.5-5.5) span a wider spatial and temporal range. For our source parameter calculations, we form narrow-frequency band envelopes for pairs of earthquakes within the earthquake clusters to compute spectral ratios for each pair. We determine seismic moment, corner frequency, and earthquake stress drop for each earthquake from these spectral ratios. We compare the source parameters for events within the clusters to examine temporal variations and compare between clusters to explore spatial variations that could be linked to other slip heterogeneity. Preliminary results for the Nicoya region suggest nearly identical stress drop for repeating events within clusters located near the 2012 mainshock, and more variability in stress drops for earthquakes in clusters located updip and to the northwest of the mainshock.

  15. Repeated Binge-Like Ethanol Drinking Alters Ethanol Drinking Patterns and Depresses Striatal GABAergic Transmission

    PubMed Central

    Wilcox, Mark V; Carlson, Verginia C Cuzon; Sherazee, Nyssa; Sprow, Gretchen M; Bock, Roland; Thiele, Todd E; Lovinger, David M; Alvarez, Veronica A

    2014-01-01

    Repeated cycles of binge alcohol drinking and abstinence are key components in the development of dependence. However, the precise behavioral mechanisms underlying binge-like drinking and its consequences on striatal synaptic physiology remain unclear. In the present study, ethanol and water drinking patterns were recorded with high temporal resolution over 6 weeks of binge-like ethanol drinking using the ‘drinking in the dark' (DID) protocol. The bottle exchange occurring at the beginning of each session prompted a transient increase in the drinking rate that might facilitate the acquisition of ethanol binge-like drinking. Ethanol drinking mice also displayed a ‘front-loading' behavior, in which the highest rate of drinking was recorded during the first 15 min. This rate increased over weeks and paralleled the mild escalation of blood ethanol concentrations. GABAergic and glutamatergic transmission in the dorsal striatum were examined following DID. Spontaneous glutamatergic transmission and the density of dendritic spines were unchanged after ethanol drinking. However, the frequency of GABAA receptor-mediated inhibitory postsynaptic currents was depressed in medium spiny neurons of ethanol drinking mice. A history of ethanol drinking also increased ethanol preference and altered the acute ethanol effects on GABAergic transmission differentially in dorsolateral and dorsomedial striatum. Together, the study shows that the bottle exchange during DID promotes fast, voluntary ethanol drinking and that this intermittent pattern of ethanol drinking causes a depression of GABAergic transmission in the dorsal striatum. PMID:23995582

  16. Optoelectronic Instrument Monitors pH in a Culture Medium

    NASA Technical Reports Server (NTRS)

    Anderson, Melody M.; Pellis, Neal; Jeevarajan, Anthony S.; Taylor, Thomas D.

    2004-01-01

    An optoelectronic instrument monitors the pH of an aqueous cell-culture medium in a perfused rotating-wall-vessel bioreactor. The instrument is designed to satisfy the following requirements: It should be able to measure the pH of the medium continuously with an accuracy of 0.1 in the range from 6.5 to 7.5. It should be noninvasive. Any material in contact with the culture medium should be sterilizable as well as nontoxic to the cells to be grown in the medium. The biofilm that inevitably grows on any surface in contact with the medium should not affect the accuracy of the pH measurement. It should be possible to obtain accurate measurements after only one calibration performed prior to a bioreactor cell run. The instrument should be small and lightweight. The instrument includes a quartz cuvette through which the culture medium flows as it is circulated through the bioreactor. The cuvette is sandwiched between light source on one side and a photodetector on the other side. The light source comprises a red and a green light-emitting diode (LED) that are repeatedly flashed in alternation with a cycle time of 5 s. The responses of the photodiode to the green and red LEDs are processed electronically to obtain a quantity proportional to the ratio between the amounts of green and red light transmitted through the medium.

  17. Does Repeating a Year Improve Performance? The Case of Teaching English

    ERIC Educational Resources Information Center

    Morrison, Keith; No, Anna Ieong On

    2007-01-01

    This paper examines whether having school students repeat a year improves their performance, focusing on learning English as a foreign language. It takes students' English examination results from five years from a Chinese-medium school, together with data on their learning styles and learning strategies. Drawing on local cultural and pedagogic…

  18. Large Torque Variations in Two Soft Gamma Repeaters

    NASA Technical Reports Server (NTRS)

    Woods, Peter M.; Kouveliotou, Chryssa; Gogus, Ersin; Finger, Mark H.; Swank, Jean; Markwardt, Craig B.; Hurley, Kevin; vanderKlis, Michiel

    2002-01-01

    We have monitored the pulse frequencies of the two soft gamma repeaters SGR 1806-20 and SGR 1900+14 through the beginning of year 2001 using primarily Rossi X-Ray Timing Explorer Proportional Counter Array observations. In both sources, we observe large changes in the spin-down torque up to a factor of approximately 4, which persist for several months. Using long-baseline phase-connected timing solutions as well as the overall frequency histories, we construct torque noise power spectra for each SGR (Soft Gamma Repeater). The power spectrum of each source is very red (power-law slope is approximately -3.5). The torque noise power levels are consistent with some accreting systems on timescales of approximately 1 yr, yet the full power spectrum is much steeper in frequency than any known accreting source. To the best of our knowledge, torque noise power spectra with a comparably steep frequency dependence have been seen only in young, glitching radio pulsars (e.g., Vela). The observed changes in spin-down rate do not correlate with burst activity; therefore, the physical mechanisms behind each phenomenon are also likely unrelated. Within the context of the magnetar model, seismic activity can not account for both the bursts and the long-term torque changes unless the seismically active regions are decoupled from one another.

  19. Frequency spirals

    NASA Astrophysics Data System (ADS)

    Ottino-Löffler, Bertrand; Strogatz, Steven H.

    2016-09-01

    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 "frequency spirals." These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, 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, frequency 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 frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  20. A Semiparametric Bayesian Model for Repeatedly Repeated Binary Outcomes

    PubMed Central

    Quintana, Fernando A.; Müller, Peter; Rosner, Gary L.; Relling, Mary V.

    2009-01-01

    Summary We discuss the analysis of data from single nucleotide polymorphism (SNP) arrays comparing tumor and normal tissues. The data consist of sequences of indicators for loss of heterozygosity (LOH) and involve three nested levels of repetition: chromosomes for a given patient, regions within chromosomes, and SNPs nested within regions. We propose to analyze these data using a semiparametric model for multi-level repeated binary data. At the top level of the hierarchy we assume a sampling model for the observed binary LOH sequences that arises from a partial exchangeability argument. This implies a mixture of Markov chains model. The mixture is defined with respect to the Markov transition probabilities. We assume a nonparametric prior for the random mixing measure. The resulting model takes the form of a semiparametric random effects model with the matrix of transition probabilities being the random effects. The model includes appropriate dependence assumptions for the two remaining levels of the hierarchy, i.e., for regions within chromosomes and for chromosomes within patient. We use the model to identify regions of increased LOH in a dataset coming from a study of treatment-related leukemia in children with an initial cancer diagnostic. The model successfully identifies the desired regions and performs well compared to other available alternatives. PMID:19746193

  1. Analytic descriptions of cylindrical electromagnetic waves in a nonlinear medium.

    PubMed

    Xiong, Hao; Si, Liu-Gang; Yang, Xiaoxue; Wu, Ying

    2015-01-01

    A simple but highly efficient approach for dealing with the problem of cylindrical electromagnetic waves propagation in a nonlinear medium is proposed based on an exact solution proposed recently. We derive an analytical explicit formula, which exhibiting rich interesting nonlinear effects, to describe the propagation of any amount of cylindrical electromagnetic waves in a nonlinear medium. The results obtained by using the present method are accurately concordant with the results of using traditional coupled-wave equations. As an example of application, we discuss how a third wave affects the sum- and difference-frequency generation of two waves propagation in the nonlinear medium.

  2. Analytic descriptions of cylindrical electromagnetic waves in a nonlinear medium

    PubMed Central

    Xiong, Hao; Si, Liu-Gang; Yang, Xiaoxue; Wu, Ying

    2015-01-01

    A simple but highly efficient approach for dealing with the problem of cylindrical electromagnetic waves propagation in a nonlinear medium is proposed based on an exact solution proposed recently. We derive an analytical explicit formula, which exhibiting rich interesting nonlinear effects, to describe the propagation of any amount of cylindrical electromagnetic waves in a nonlinear medium. The results obtained by using the present method are accurately concordant with the results of using traditional coupled-wave equations. As an example of application, we discuss how a third wave affects the sum- and difference-frequency generation of two waves propagation in the nonlinear medium. PMID:26073066

  3. Repeated checking causes memory distrust.

    PubMed

    van den Hout, Marcel; Kindt, Merel

    2003-03-01

    This paper attempts to explain why in obsessive-compulsive disorder (OCD) checkers distrust in memory persists despite extensive checking. It is argued that: (1) repeated checking increases familiarity with the issues checked; (2) increased familiarity promotes conceptual processing which inhibits perceptual processing; (3) inhibited perceptual processing makes recollections less vivid and detailed and finally; (4) reduction in vividness and detail promotes distrust in memory. An interactive computer animation was developed in which participants had to perform checking rituals on a virtual gas stove. Two separate experiments were carried out with n=39 (Experiment I) and n=40 (Experiment II) healthy participants. In both studies, the control group and the experimental group were given the same pre-test and post-test on the virtual gas stove. In between, the experimental group engaged in 'relevant checking', i.e. checking the gas stove, while the control group engaged in 'irrelevant checking', i.e. checking virtual light bulbs. In both experiments there were powerful effects of repeated 'relevant checking': while actual memory accuracy remained unaffected, the vividness and detail of the recollections were greatly reduced. Most pertinently, in both experiments relevant checking undermined confidence in memory. No such effects were observed in the control group. One might argue that the pre-test/post-test design may have made the control group anticipate a memory assessment at the post-test and that this artifact made them relatively alert producing memory confidence at post test that was artificially high. A third experiment was carried out (n=2 x 20) in which no pre-test was given while, other than that, Experiment III was identical to the first two experiments. Results confirmed earlier findings: compared to the irrelevant checking control group, recollections in the relevant checking group were non-vivid, non-detailed while confidence in memory was low. The theory

  4. Trinucleotide repeat expansion in the FRAXE locus is not common among institutionalized individuals with non-specific developmental disabilities

    SciTech Connect

    Holden, J.J.A.; Julien-Inalsingh, C.; Fidler, K.

    1996-08-09

    Expansion of a polymorphic GCC-repeat at the FRAXE locus has been associated with expression of chromosome fragility at this site and cognitive impairment in some individuals previously testing negative for CGG-repeat expansion in the fragile X mental retardation-1 (FMR1) gene. To determine the frequency of FRAXE triplet repeat expansion among persons with developmental disability, 396 individuals from two institutions were studied, all of whom were negative for FMR1 repeat expansion. Clinically, there was a wide range of mental impairment, with the majority (61.1%) being severely to profoundly affected. The distribution of FRAXE GCC-repeat numbers in the study population was 5-38:28 (5.6%) with 10-14 repeats; 366 (73.8%) with 15-19 repeats; 74 (14.9%) with 20-24 repeats; 20 (4.0%) with 25-29 repeats; and 5 (1.0%) with 30-38 repeats, with no individuals demonstrating repeat expansion. One profoundly retarded male was found to have a deletion of about 40 bp. Southern blots of HindIII-digested DNAs from individuals with {ge}26 repeats all showed normal patterns. These results suggest that FRAXE GCC-repeat expansion is not a common cause of developmental disability in institutionalized persons with mild to profound mental retardation. 15 refs., 1 fig., 2 tabs.

  5. Single and repeated elective abortions in Japan: a psychosocial study.

    PubMed

    Kitamura, T; Toda, M A; Shima, S; Sugawara, M

    1998-09-01

    Despite its social, legal and medical importance, termination of pregnancy (TOP) (induced abortion) has rarely been the focus of psychosocial research. Of a total of 1329 women who consecutively attended the antenatal clinic of a general hospital in Japan, 635 were expecting their first baby. Of these 635 women, 103 (16.2%) had experienced TOP once previously (first aborters), while 47 (7.4%) had experienced TOP two or more times (repeated aborters). Discriminant function analysis was performed using psychosocial variables found to be significantly associated with either first abortion or repeated abortion in bivariate analyses. This revealed that both first and repeated aborters could be predicted by smoking habits and an unwanted current pregnancy while the repeated aborters appear to differ from first aborters in having a longer pre-marital dating period, non-arranged marriages, smoking habits, early maternal loss experience or a low level of maternal care during childhood. These findings suggest that both the frequency of abortion and its repetition have psychosocial origins.

  6. Modeling Repeatedly Flaring δ Sunspots.

    PubMed

    Chatterjee, Piyali; Hansteen, Viggo; Carlsson, Mats

    2016-03-11

    Active regions (ARs) appearing on the surface of the Sun are classified into α, β, γ, and δ by the rules of the Mount Wilson Observatory, California on the basis of their topological complexity. Amongst these, the δ sunspots are known to be superactive and produce the most x-ray flares. Here, we present results from a simulation of the Sun by mimicking the upper layers and the corona, but starting at a more primitive stage than any earlier treatment. We find that this initial state consisting of only a thin subphotospheric magnetic sheet breaks into multiple flux tubes which evolve into a colliding-merging system of spots of opposite polarity upon surface emergence, similar to those often seen on the Sun. The simulation goes on to produce many exotic δ sunspot associated phenomena: repeated flaring in the range of typical solar flare energy release and ejective helical flux ropes with embedded cool-dense plasma filaments resembling solar coronal mass ejections.

  7. TOO Observations Soft Gamma Repeaters

    NASA Technical Reports Server (NTRS)

    vanParadijs, J.

    1998-01-01

    The goal of the project was to study the X-ray properties of the persistent and burst emission of Soft Gamma Repeaters (SGRs) during periods of burst activity. We monitored this activity with BATSE on the Compton Gamma-Ray Observatory, and made X-ray observations with the Rossi X-ray Timing Explorer (RXTE). SGR1806-20 became active in October 1996. We made observations with the PCA on the RXTE in November 1996. In the RXTE data we detected several hundred brief SGR events, which occurred in clear bunches, and persistent emission. From a Fouder analysis of the persistent emission (excluding time intervals with bursts) we found a period of 7.47 s. These pulsations are also present in RXTE data taken several weeks later (PI Dr. T. Strohmayer), which were combined with our data. Comparison with ASCA data taken in 1993 and 1995 shows that the period, which reflects the spin of a neutron star, increases on a time scale of 1500 years. These results show that SGR1 806-20 is a neutron star with a superstrong magnetic field (about 1"15) Gauss), thereby establishing, for the first time, the existence of magnetars.

  8. Observations of Soft Gamma Repeaters

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2005-01-01

    Magnetars (Soft Gamma Repeaters and Anomalous X-ray Pulsars) are a subclass of neutron stars characterized by their recurrent X-ray bursts. While in an active (bursting) state (lasting anywhere between days and years), they are emitting hundreds of predominantly soft (kl'=30 kev), short (0.1 - 100 ms long) events. Their quiescent source X-ray light curves exhibit pulsations in the narrow range of 5-1 1 s; estimates of these rotational period rate changes (spin-down) indicate that their magnetic fields are extremely high, of the order of 10A14-10A15 G. Such high B-field objects, dubbed "magnetars", had been predicted to exist in 1992, but the first concrete observational evidence was obtained in 1998 for two of these sources. Very recently, SGR1806-20 emitted a giant flare, which was detected in the radio with a multitude of telescopes under an extensive international campaign. These observations have revealed exciting new results, never seen before in any of the other magnetar sources. I will discuss here these results and their relevance to our understanding of the nature of magnetars.

  9. Repeatability of adaptation in experimental populations of different sizes

    PubMed Central

    Lachapelle, Josianne; Reid, Joshua; Colegrave, Nick

    2015-01-01

    The degree to which evolutionary trajectories and outcomes are repeatable across independent populations depends on the relative contribution of selection, chance and history. Population size has been shown theoretically and empirically to affect the amount of variation that arises among independent populations adapting to the same environment. Here, we measure the contribution of selection, chance and history in different-sized experimental populations of the unicellular alga Chlamydomonas reinhardtii adapting to a high salt environment to determine which component of evolution is affected by population size. We find that adaptation to salt is repeatable at the fitness level in medium (Ne = 5 × 104) and large (Ne = 4 × 105) populations because of the large contribution of selection. Adaptation is not repeatable in small (Ne = 5 × 103) populations because of large constraints from history. The threshold between stochastic and deterministic evolution in this case is therefore between effective population sizes of 103 and 104. Our results indicate that diversity across populations is more likely to be maintained if they are small. Experimental outcomes in large populations are likely to be robust and can inform our predictions about outcomes in similar situations. PMID:25788593

  10. Strengthening concept learning by repeated testing

    PubMed Central

    Wiklund-Hörnqvist, Carola; Jonsson, Bert; Nyberg, Lars

    2014-01-01

    The aim of this study was to examine whether repeated testing with feedback benefits learning compared to rereading of introductory psychology key-concepts in an educational context. The testing effect was examined immediately after practice, after 18 days, and at a five-week delay in a sample of undergraduate students (n = 83). The results revealed that repeated testing with feedback significantly enhanced learning compared to rereading at all delays, demonstrating that repeated retrieval enhances retention compared to repeated encoding in the short- and the long-term. In addition, the effect of repeated testing was beneficial for students irrespectively of working memory capacity. It is argued that teaching methods involving repeated retrieval are important to consider by the educational system. PMID:24313425

  11. Strengthening concept learning by repeated testing.

    PubMed

    Wiklund-Hörnqvist, Carola; Jonsson, Bert; Nyberg, Lars

    2014-02-01

    The aim of this study was to examine whether repeated testing with feedback benefits learning compared to rereading of introductory psychology key-concepts in an educational context. The testing effect was examined immediately after practice, after 18 days, and at a five-week delay in a sample of undergraduate students (n = 83). The results revealed that repeated testing with feedback significantly enhanced learning compared to rereading at all delays, demonstrating that repeated retrieval enhances retention compared to repeated encoding in the short- and the long-term. In addition, the effect of repeated testing was beneficial for students irrespectively of working memory capacity. It is argued that teaching methods involving repeated retrieval are important to consider by the educational system.

  12. Transformation-associated recombination between diverged and homologous DNA repeats is induced by strand breaks

    SciTech Connect

    Larionov, V.; Kouprina, N. |; Edlarov, M. |; Perkins, E.; Porter, G.; Resnick, M.A.

    1993-12-31

    Rearrangement and deletion within plasmid DNA is commonly observed during transformation. We have examined the mechanisms of transformation-associated recombination in the yeast Saccharomyces cerevisiae using a plasmid system which allowed the effects of physical state and/or extent of homology on recombination to be studied. The plasmid contains homologous or diverged (19%) DNA repeats separated by a genetically detectable color marker. Recombination during transformation for covalently closed circular plasmids was over 100-fold more frequent than during mitotic growth. The frequency of recombination is partly dependent on the method of transformation in that procedures involving lithium acetate or spheroplasting yield higher frequencies than electroporation. When present in the repeats, unique single-strand breaks that are ligatable, as well as double-strand breaks, lead to high levels of recombination between diverged and identical repeats. The transformation-associated recombination between repeat DNA`s is under the influence of the RADS2, RADI and the RNCI genes,

  13. Wave propagation in a random medium

    NASA Technical Reports Server (NTRS)

    Lee, R. W.; Harp, J. C.

    1969-01-01

    A simple technique is used to derive statistical characterizations of the perturbations imposed upon a wave (plane, spherical or beamed) propagating through a random medium. The method is essentially physical rather than mathematical, and is probably equivalent to the Rytov method. The limitations of the method are discussed in some detail; in general they are restrictive only for optical paths longer than a few hundred meters, and for paths at the lower microwave frequencies. Situations treated include arbitrary path geometries, finite transmitting and receiving apertures, and anisotropic media. Results include, in addition to the usual statistical quantities, time-lagged functions, mixed functions involving amplitude and phase fluctuations, angle-of-arrival covariances, frequency covariances, and other higher-order quantities.

  14. Repeated Witnessing of Conspecifics in Pain: Effects on Emotional Contagion.

    PubMed

    Carrillo, Maria; Migliorati, Filippo; Bruls, Rune; Han, Yingying; Heinemans, Mirjam; Pruis, Ilanah; Gazzola, Valeria; Keysers, Christian

    2015-01-01

    Witnessing of conspecifics in pain has been shown to elicit socially triggered freezing in rodents. It is unknown how robust this response is to repeated exposure to a cage-mate experiencing painful stimulation. To address this question, shock-experienced Observer rats repeatedly witnessed familiar Demonstrators receive painful footshocks (six sessions). Results confirm that Observers freeze during the first testing session. The occurrence of this behaviour however gradually diminished as the experimental sessions progressed, reaching minimal freezing levels by the end of the experiments. In contrast, the appearance and continuous increase in the frequency of yawning, a behavior that was inhibited by metyrapone (i.e,. a glucocorticoid synthesis blocker), might represent an alternative coping strategy, suggesting that the observer's reduced freezing does not necessarily indicate a disappearance in the affective response to the Demonstrator's distress. PMID:26356506

  15. Repeated Witnessing of Conspecifics in Pain: Effects on Emotional Contagion

    PubMed Central

    Bruls, Rune; Han, Yingying; Heinemans, Mirjam; Pruis, Ilanah; Gazzola, Valeria; Keysers, Christian

    2015-01-01

    Witnessing of conspecifics in pain has been shown to elicit socially triggered freezing in rodents. It is unknown how robust this response is to repeated exposure to a cage-mate experiencing painful stimulation. To address this question, shock-experienced Observer rats repeatedly witnessed familiar Demonstrators receive painful footshocks (six sessions). Results confirm that Observers freeze during the first testing session. The occurrence of this behaviour however gradually diminished as the experimental sessions progressed, reaching minimal freezing levels by the end of the experiments. In contrast, the appearance and continuous increase in the frequency of yawning, a behavior that was inhibited by metyrapone (i.e,. a glucocorticoid synthesis blocker), might represent an alternative coping strategy, suggesting that the observer’s reduced freezing does not necessarily indicate a disappearance in the affective response to the Demonstrator’s distress. PMID:26356506

  16. Repeated games and direct reciprocity under active linking.

    PubMed

    Pacheco, Jorge M; Traulsen, Arne; Ohtsuki, Hisashi; Nowak, Martin A

    2008-02-21

    Direct reciprocity relies on repeated encounters between the same two individuals. Here we examine the evolution of cooperation under direct reciprocity in dynamically structured populations. Individuals occupy the vertices of a graph, undergoing repeated interactions with their partners via the edges of the graph. Unlike the traditional approach to evolutionary game theory, where individuals meet at random and have no control over the frequency or duration of interactions, we consider a model in which individuals differ in the rate at which they seek new interactions. Moreover, once a link between two individuals has formed, the productivity of this link is evaluated. Links can be broken off at different rates. Whenever the active dynamics of links is sufficiently fast, population structure leads to a simple transformation of the payoff matrix, effectively changing the game under consideration, and hence paving the way for reciprocators to dominate defectors. We derive analytical conditions for evolutionary stability.

  17. Interstellar medium simulations

    NASA Astrophysics Data System (ADS)

    Breitschwerdt, D.; de Avillez, M. A.; Feige, J.; Dettbarn, C.

    2012-06-01

    In this review we critically assess numerical simulations of the interstellar medium (ISM), and argue that 3D high resolution calculations are the most promising method to determine the structure of the interstellar gas and follow its evolution well into the nonlinear regime. Based on a Riemann solver adaptive mesh refinement code, we present a model, which fulfills the basic requirements of running it sufficiently long in order to erase memory effects of the initial conditions, set up a disk-halo fountain flow cycle, for converging solutions with increasing mesh refinement. We obtain the following results: (i) in a supernova driven ISM, high Reynolds number turbulence generates structures on all scales, (ii) the volume filling factor of the hot gas is substantially reduced due to the fountain flow, (iii) gas clouds are transient shock compressed layers, (iv) more than half of the gas mass resides in thermally unstable regimes, (v) O VI is distributed in patchy mixing layers, with the derived column densities being in agreement with FUSE and Copernicus observations, (vi) the electron density distribution up to distances of 8 kpc in the disk is consistent with pulsar dispersion measure observations, provided that the electron and ionization structure are not in equilibrium, (vii) the interstellar cooling function depends both on space and time (and not only on temperature and metallicity), (viii) the Local Bubble has been produced by 14-20 supernovae about 14 Myr ago, exploding in a moving group on its path through the local ISM, (ix) the nearest supernova explosion to Earth occurred 2.2 {×} 106 yr ago at a distance of {˜} 85 pc, in agreement with measurements of the radionuclide 60Fe found in the ferromanganese crust on the ocean floor.

  18. Short Tandem Repeat DNA Internet Database

    National Institute of Standards and Technology Data Gateway

    SRD 130 Short Tandem Repeat DNA Internet Database (Web, free access)   Short Tandem Repeat DNA Internet Database is intended to benefit research and application of short tandem repeat DNA markers for human identity testing. Facts and sequence information on each STR system, population data, commonly used multiplex STR systems, PCR primers and conditions, and a review of various technologies for analysis of STR alleles have been included.

  19. Understanding and identifying amino acid repeats.

    PubMed

    Luo, Hong; Nijveen, Harm

    2014-07-01

    Amino acid repeats (AARs) are abundant in protein sequences. They have particular roles in protein function and evolution. Simple repeat patterns generated by DNA slippage tend to introduce length variations and point mutations in repeat regions. Loss of normal and gain of abnormal function owing to their variable length are potential risks leading to diseases. Repeats with complex patterns mostly refer to the functional domain repeats, such as the well-known leucine-rich repeat and WD repeat, which are frequently involved in protein–protein interaction. They are mainly derived from internal gene duplication events and stabilized by ‘gate-keeper’ residues, which play crucial roles in preventing inter-domain aggregation. AARs are widely distributed in different proteomes across a variety of taxonomic ranges, and especially abundant in eukaryotic proteins. However, their specific evolutionary and functional scenarios are still poorly understood. Identifying AARs in protein sequences is the first step for the further investigation of their biological function and evolutionary mechanism. In principle, this is an NP-hard problem, as most of the repeat fragments are shaped by a series of sophisticated evolutionary events and become latent periodical patterns. It is not possible to define a uniform criterion for detecting and verifying various repeat patterns. Instead, different algorithms based on different strategies have been developed to cope with different repeat patterns. In this review, we attempt to describe the amino acid repeat-detection algorithms currently available and compare their strategies based on an in-depth analysis of the biological significance of protein repeats. PMID:23418055

  20. Approaching improved adhesive bonding repeatability

    NASA Astrophysics Data System (ADS)

    Schlette, Christian; Müller, Tobias; Roβmann, Jürgen; Brecher, Christian

    2016-03-01

    Today, the precision of micro-optics assembly is mostly limited by the accuracy of the bonding process ― and in the case of adhesive bonding by the prediction and compensation of adhesive shrinkage during curing. In this contribution, we present a novel approach to address adhesive bonding based on hybrid control system theory. In hybrid control, dynamic systems are described as "plants" which produce discrete and/or continuous outputs from given discrete and/or continuous inputs, thus yielding a hybrid state space description of the system. The task of hybrid controllers is to observe the plant and to generate a discrete and/or continuous input sequence that guides or holds the plant in a desired target state region while avoiding invalid or unwanted intermediate states. Our approach is based on a series of experiments carried out in order to analyze, define and decouple the dependencies of adhesive shrinkage on multiple parameters, such as application geometries, fixture forces and UV intensities. As some of the dependencies describe continuous effects (e.g. shrinkage from UV intensity) and other dependencies describe discrete state transitions (e.g. fixture removal during curing), the resulting model of the overall bonding process is a hybrid dynamic system in the general case. For this plant model, we then propose a concept of sampling-based parameter search as a basis to design suitable hybrid controllers, which have the potential to optimize process control for a selection of assembly steps, thus improving the repeatability of related production steps like beam-shaping optics or mounting of turning mirrors for fiber coupling.

  1. De Novo Repeat Classification and Fragment Assembly

    PubMed Central

    Pevzner, Paul A.; Tang, Haixu; Tesler, Glenn

    2004-01-01

    Repetitive sequences make up a significant fraction of almost any genome, and an important and still open question in bioinformatics is how to represent all repeats in DNA sequences. We propose a new approach to repeat classification that represents all repeats in a genome as a mosaic of sub-repeats. Our key algorithmic idea also leads to new approaches to multiple alignment and fragment assembly. In particular, we show that our FragmentGluer assembler improves on Phrap and ARACHNE in assembly of BACs and bacterial genomes. PMID:15342561

  2. Tandem repeats derived from centromeric retrotransposons

    PubMed Central

    2013-01-01

    Background Tandem repeats are ubiquitous and abundant in higher eukaryotic genomes and constitute, along with transposable elements, much of DNA underlying centromeres and other heterochromatic domains. In maize, centromeric satellite repeat (CentC) and centromeric retrotransposons (CR), a class of Ty3/gypsy retrotransposons, are enriched at centromeres. Some satellite repeats have homology to retrotransposons and several mechanisms have been proposed to explain the expansion, contraction as well as homogenization of tandem repeats. However, the origin and evolution of tandem repeat loci remain largely unknown. Results CRM1TR and CRM4TR are novel tandem repeats that we show to be entirely derived from CR elements belonging to two different subfamilies, CRM1 and CRM4. Although these tandem repeats clearly originated in at least two separate events, they are derived from similar regions of their respective parent element, namely the long terminal repeat (LTR) and untranslated region (UTR). The 5′ ends of the monomer repeat units of CRM1TR and CRM4TR map to different locations within their respective LTRs, while their 3′ ends map to the same relative position within a conserved region of their UTRs. Based on the insertion times of heterologous retrotransposons that have inserted into these tandem repeats, amplification of the repeats is estimated to have begun at least ~4 (CRM1TR) and ~1 (CRM4TR) million years ago. Distinct CRM1TR sequence variants occupy the two CRM1TR loci, indicating that there is little or no movement of repeats between loci, even though they are separated by only ~1.4 Mb. Conclusions The discovery of two novel retrotransposon derived tandem repeats supports the conclusions from earlier studies that retrotransposons can give rise to tandem repeats in eukaryotic genomes. Analysis of monomers from two different CRM1TR loci shows that gene conversion is the major cause of sequence variation. We propose that successive intrastrand deletions

  3. Mode-medium instability in an unstable resonator

    NASA Technical Reports Server (NTRS)

    Sung, C. C.; Li, Y. Q.; Smithers, Martin E.

    1988-01-01

    The mode-medium instability of an active medium in an unstable resonator is investigated. The asymptotic solution due to Horwitz (1973), valid for large Fresnel numbers in an empty cavity, is modified by introducing gain/phase sheets in front of the resonator mirrors. The effect of medium coupling to the mode in the cavity is obtained by introducing a general time-independent Green's function in the Fox-Li (1961) formulation. The time evolution is then obtained by repeated integration of the beam propagation in the cavity. The diffractive terms are shown to grow rapidly at the expense of the geometric term. This instability responsible for the deterioration of the beam quality is studied numerically for a CO2 lasing system as an example.

  4. The Influence of Primary and Secondary DNA Structure in Deletion and Duplication between Direct Repeats in Escherichia Coli

    PubMed Central

    Trinh, T. Q.; Sinden, R. R.

    1993-01-01

    We describe a system to measure the frequency of both deletions and duplications between direct repeats. Short 17- and 18-bp palindromic and nonpalindromic DNA sequences were cloned into the EcoRI site within the chloramphenicol acetyltransferase gene of plasmids pBR325 and pJT7. This creates an insert between direct repeated EcoRI sites and results in a chloramphenicol-sensitive phenotype. Selection for chloramphenicol resistance was utilized to select chloramphenicol resistant revertants that included those with precise deletion of the insert from plasmid pBR325 and duplication of the insert in plasmid pJT7. The frequency of deletion or duplication varied more than 500-fold depending on the sequence of the short sequence inserted into the EcoRI site. For the nonpalindromic inserts, multiple internal direct repeats and the length of the direct repeats appear to influence the frequency of deletion. Certain palindromic DNA sequences with the potential to form DNA hairpin structures that might stabilize the misalignment of direct repeats had a high frequency of deletion. Other DNA sequences with the potential to form structures that might destabilize misalignment of direct repeats had a very low frequency of deletion. Duplication mutations occurred at the highest frequency when the DNA between the direct repeats contained no direct or inverted repeats. The presence of inverted repeats dramatically reduced the frequency of duplications. The results support the slippage-misalignment model, suggesting that misalignment occurring during DNA replication leads to deletion and duplication mutations. The results also support the idea that the formation of DNA secondary structures during DNA replication can facilitate and direct specific mutagenic events. PMID:8325478

  5. The effect of an official match on repeated sprint ability in junior basketball players.

    PubMed

    Caprino, Davide; Clarke, Neil David; Delextrat, Anne

    2012-01-01

    The aim of this study was to investigate the effect of an official basketball match on repeated sprint ability indices in male junior players. Ten (16 ± 1 years old; 183.6 ± 7.0 cm; 76.6 ± 8.0 kg) starting players for their teams performed three repeated sprint ability tests, before, at half-time and immediately after an official match. Each repeated sprint ability test consisted of 10 shuttle-run sprints of 30 m (15 + 15 m) separated by 30 seconds of passive recovery. The matches were video-taped to determine the frequency of eight types of movement patterns, and blood lactate concentration was measured before and immediately after each repeated sprint ability test. Differences in total time, ideal time and percentage decrement between tests was assessed by a one-way analysis of variance (ANOVA) with repeated measures, while a two-way ANOVA with repeated measures was used to identify differences in blood lactate concentration. The main results indicated a significant decrease in total movement frequency (-9.9%), high-intensity activity frequency (-13.3%), run frequency (-13.0%) and sprint frequency (-23.3%) in the second compared to the first half, and significantly worse total time and ideal time at the end of the match, compared to the start and half-time (differences ranging from -2.1% to -2.9%, P < 0.05). The practical implications of these findings suggest that regional basketball players should participate in conditioning sessions that focus on the improvement of repeated sprint ability.

  6. New medium licensed for campylobacter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A medium, “Campy-Cefex”, has been licensed by the ARS Office of Technology Transfer with Becton Dickinson (No. 1412-002) and Neogen (No. 1412-001) based on patent No. 5,891,709, “Campy-Cefex Selective and Differential Medium for Campylobacter” by Dr. Norman Stern of the Poultry Microbiological Safet...

  7. Meiotic stability and polymorphism of CAG repeat in normal chromosome at SCA1 locus

    SciTech Connect

    Limprasert, P.; Nouri, N.; Keats, B.J.B.

    1994-09-01

    Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant neurodegenerative disorder associated with an unstable and expanded CAG repeat. We analyzed the CAG repeat in normal chromosomes from various sources including SCA1 and nonSCA1 families, and Caucasian, African American, Eskimo, South American Indian and Acadian populations. The range of CAG repeats is 10-37 in normal alleles while the disease allele contains 45-65 repeats in our studies. To determine unbiased normal allelic frequencies, we analyzed data from unrelated individuals in each group. The significance of differences in allelic frequencies among the groups was determined by a chi-square test. Caucasian and Acadian frequencies were similar (p = 0.23), but highly significant differences were found among the Caucasians, African Americans, Eskimos, and South American Indians (p < 0.0005), and the range of allele sizes was much narrower in Eskimos and South American Indians. To determine if the normal chromosome is susceptible to meiotic instability, we examined members of 19 Caucasian and 24 Acadian families. Normal sized CAG repeats were faithfully transmitted from parents to offspring without any alteration in CAG number in 236 meioses. Transmission of CAG repeats in normal alleles were also stable in our SCA1 family. However, the disease allele was associated with a significant degree of instability. Some patients showed 2 expanded bands in DNA prepared from untransformed blood cells. This finding suggest mitotic instability of the disease allele.

  8. Power enhanced frequency conversion system

    NASA Technical Reports Server (NTRS)

    Sanders, Steven (Inventor); Lang, Robert J. (Inventor); Waarts, Robert G. (Inventor)

    2001-01-01

    A frequency conversion system includes at least one source providing a first near-IR wavelength output including a gain medium for providing high power amplification, such as double clad fiber amplifier, a double clad fiber laser or a semiconductor tapered amplifier to enhance the power output level of the near-IR wavelength output. The NFM device may be a difference frequency mixing (DFM) device or an optical parametric oscillation (OPO) device. Pump powers are gain enhanced by the addition of a rare earth amplifier or oscillator, or a Ra-man/Brillouin amplifier or oscillator between the high power source and the NFM device.

  9. Evaluating a Group Repeated Reading Intervention

    ERIC Educational Resources Information Center

    Klubnik, Cynthia Adele

    2009-01-01

    Fluency has been identified as an important component of effective reading instruction, and repeated reading has been shown to improve oral reading fluency. In order to improve the efficiency of repeated reading interventions, more research is needed on the effectiveness of small group reading interventions. An alternating treatments, single…

  10. The Effects of Repeaters on Test Equating.

    ERIC Educational Resources Information Center

    Andrulis, Richard S.; And Others

    1978-01-01

    The effects of repeaters (testees included in both administrations of two forms of a test) on the test equating process are examined. It is shown that repeaters do effect test equating and tend to lower the cutoff point for passing the test. (JKS)

  11. The Effects of Repeaters on Test Equating.

    ERIC Educational Resources Information Center

    Andrulis, Richard S.; And Others

    The purpose of this investigation was to establish the effects of repeaters on test equating. Since consideration was not given to repeaters in test equating, such as in the derivation of equations by Angoff (1971), the hypothetical effect needed to be established. A case study was examined which showed results on a test as expected; overall mean…

  12. Native DNA repeats and methylation in Ascobolus.

    PubMed Central

    Goyon, C; Rossignol, J L; Faugeron, G

    1996-01-01

    We identified two classes of native dispersed DNA repeats in the Ascobolus genome. The first class consisted of several kilobase long, methylated repeats. These repeats, named Mars (methylated Ascobolus repeated sequences), fell in one family of LINE-like elements and in three families of LTR-containing retrotransposable elements. The methylation features of Mars elements were those expected if they were natural targets for the MIP (methylation induced premeiotically) previously discovered in Ascobolus. The second class consisted of short repeats, approximately 100 bp long, corresponding to 5S rRNA and tRNA genes. As expected from their size, which was too small to allow MIP to occur, they were unmethylated, as were 26 kb of unique sequences tested. These observations are consistent with the hypothesis that MIP is targeted at natural DNA repeats and constitutes a defensive process against the detrimental consequences of the spreading of mobile elements throughout the genome. The 9 kb tandem repeats harbouring the 28S, 18S and 5.8S rRNA genes displayed methylation features suggesting that rDNA methylation proceeds through a process other than MIP. PMID:8811089

  13. Finding and Characterizing Repeats in Plant Genomes.

    PubMed

    Nicolas, Jacques; Peterlongo, Pierre; Tempel, Sébastien

    2016-01-01

    Plant genomes contain a particularly high proportion of repeated structures of various types. This chapter proposes a guided tour of available software that can help biologists to look for these repeats and check some hypothetical models intended to characterize their structures. Since transposable elements are a major source of repeats in plants, many methods have been used or developed for this large class of sequences. They are representative of the range of tools available for other classes of repeats and we have provided a whole section on this topic as well as a selection of the main existing software. In order to better understand how they work and how repeats may be efficiently found in genomes, it is necessary to look at the technical issues involved in the large-scale search of these structures. Indeed, it may be hard to keep up with the profusion of proposals in this dynamic field and the rest of the chapter is devoted to the foundations of the search for repeats and more complex patterns. The second section introduces the key concepts that are useful for understanding the current state of the art in playing with words, applied to genomic sequences. This can be seen as the first stage of a very general approach called linguistic analysis that is interested in the analysis of natural or artificial texts. Words, the lexical level, correspond to simple repeated entities in texts or strings. In fact, biologists need to represent more complex entities where a repeat family is built on more abstract structures, including direct or inverted small repeats, motifs, composition constraints as well as ordering and distance constraints between these elementary blocks. In terms of linguistics, this corresponds to the syntactic level of a language. The last section introduces concepts and practical tools that can be used to reach this syntactic level in biological sequence analysis. PMID:26519414

  14. Finding and Characterizing Repeats in Plant Genomes.

    PubMed

    Nicolas, Jacques; Peterlongo, Pierre; Tempel, Sébastien

    2016-01-01

    Plant genomes contain a particularly high proportion of repeated structures of various types. This chapter proposes a guided tour of available software that can help biologists to look for these repeats and check some hypothetical models intended to characterize their structures. Since transposable elements are a major source of repeats in plants, many methods have been used or developed for this large class of sequences. They are representative of the range of tools available for other classes of repeats and we have provided a whole section on this topic as well as a selection of the main existing software. In order to better understand how they work and how repeats may be efficiently found in genomes, it is necessary to look at the technical issues involved in the large-scale search of these structures. Indeed, it may be hard to keep up with the profusion of proposals in this dynamic field and the rest of the chapter is devoted to the foundations of the search for repeats and more complex patterns. The second section introduces the key concepts that are useful for understanding the current state of the art in playing with words, applied to genomic sequences. This can be seen as the first stage of a very general approach called linguistic analysis that is interested in the analysis of natural or artificial texts. Words, the lexical level, correspond to simple repeated entities in texts or strings. In fact, biologists need to represent more complex entities where a repeat family is built on more abstract structures, including direct or inverted small repeats, motifs, composition constraints as well as ordering and distance constraints between these elementary blocks. In terms of linguistics, this corresponds to the syntactic level of a language. The last section introduces concepts and practical tools that can be used to reach this syntactic level in biological sequence analysis.

  15. Medium-depth chemical peels.

    PubMed

    Monheit, G D

    2001-07-01

    The combination medium-depth chemical peel (Jessner's solution +35% TCA) has been accepted as a safe, reliable, and effective method for the treatment of moderate photoaging skin. This article discusses the procedure in detail, including postoperative considerations. PMID:11599398

  16. An improved holographic recording medium

    NASA Technical Reports Server (NTRS)

    Gange, R. A.

    1973-01-01

    Solid, linear chain hydrocarbons with molecular weight ranging from about 300 to 2000 can serve as long-lived recording medium in optical memory system. Suitable recording hydrocarbons include microcrystalline waxes and low molecular weight polymers or ethylene.

  17. The child accident repeater: a review.

    PubMed

    Jones, J G

    1980-04-01

    The child accident repeater is defined as one who has at least three accidents that come to medical attention within a year. The accident situation has features in common with those of the child who has a single accident through simple "bad luck", but other factors predispose him to repeated injury. In the child who has a susceptible personality, a tendency for accident repetition may be due to a breakdown in adjustment to a stressful environment. Prevention of repeat accidents should involve the usual measures considered appropriate for all children as well as an attempt to provide treatment of significant maladjustment and modification of a stressful environment.

  18. Do gamma-ray burst sources repeat?

    NASA Technical Reports Server (NTRS)

    Meegan, C. A.; Hartmann, D. H.; Brainerd, J. J.; Briggs, M.; Paciesas, W. S.; Pendleton, G.; Kouveliotou, C.; Fishman, G.; Blumenthal, G.; Brock, M.

    1994-01-01

    The demonstration of repeated gamma-ray bursts from an individual source would severely constrain burst source models. Recent reports of evidence for repetition in the first BATSE burst catalog have generated renewed interest in this issue. Here, we analyze the angular distribution of 585 bursts of the second BATSE catalog (Meegan et al. 1994). We search for evidence of burst recurrence using the nearest and farthest neighbor statistic ad the two-point angular correlation function. We find the data to be consistent with the hypothesis that burst sources do not repeat; however, a repeater fraction of up to about 20% of the bursts cannot be excluded.

  19. Experimental measurements of the coherent field resulting from the interaction of an ultrasonic shock wave with a multiple scattering medium

    NASA Astrophysics Data System (ADS)

    Viard, Nicolas; Gianmarinaro, Bruno; Derode, Arnaud; Barrière, Christophe

    2014-04-01

    Whereas multiple scattering and shock wave formation are known to be antagonistic phenomena, this work concentrates on the interaction of an ultrasonic shock wave with a random multiple scattering medium. The shock wave is generated by long distance propagation of a short pulse (4 periods at a 3.5 MHz central frequency) in water before it encounters the scattering medium (a slab-shaped random set of parallel metallic rods). Transmitted waves are recorded over hundreds of positions along the lateral dimension of the slab to estimate the ensemble-averaged transmitted field langlephi(t)rangle, also known as the coherent wave. Experiments are repeated for different thicknesses L of the slab and different emission amplitudes. The elastic mean free path le (i.e the typical distance for the decreasing of the coherent intensity |langlephi(t)rangle|2 due to scattering) is determined as well as the harmonic rate of the averaged transmitted wave. Experimental results are discussed and compared to the linear case.

  20. A pan-European study of the C9orf72 repeat associated with FTLD: geographic prevalence, genomic instability, and intermediate repeats.

    PubMed

    van der Zee, Julie; Gijselinck, Ilse; Dillen, Lubina; Van Langenhove, Tim; Theuns, Jessie; Engelborghs, Sebastiaan; Philtjens, Stéphanie; Vandenbulcke, Mathieu; Sleegers, Kristel; Sieben, Anne; Bäumer, Veerle; Maes, Githa; Corsmit, Ellen; Borroni, Barbara; Padovani, Alessandro; Archetti, Silvana; Perneczky, Robert; Diehl-Schmid, Janine; de Mendonça, Alexandre; Miltenberger-Miltenyi, Gabriel; Pereira, Sónia; Pimentel, José; Nacmias, Benedetta; Bagnoli, Silvia; Sorbi, Sandro; Graff, Caroline; Chiang, Huei-Hsin; Westerlund, Marie; Sanchez-Valle, Raquel; Llado, Albert; Gelpi, Ellen; Santana, Isabel; Almeida, Maria Rosário; Santiago, Beatriz; Frisoni, Giovanni; Zanetti, Orazio; Bonvicini, Cristian; Synofzik, Matthis; Maetzler, Walter; Vom Hagen, Jennifer Müller; Schöls, Ludger; Heneka, Michael T; Jessen, Frank; Matej, Radoslav; Parobkova, Eva; Kovacs, Gabor G; Ströbel, Thomas; Sarafov, Stayko; Tournev, Ivailo; Jordanova, Albena; Danek, Adrian; Arzberger, Thomas; Fabrizi, Gian Maria; Testi, Silvia; Salmon, Eric; Santens, Patrick; Martin, Jean-Jacques; Cras, Patrick; Vandenberghe, Rik; De Deyn, Peter Paul; Cruts, Marc; Van Broeckhoven, Christine; van der Zee, Julie; Gijselinck, Ilse; Dillen, Lubina; Van Langenhove, Tim; Theuns, Jessie; Philtjens, Stéphanie; Sleegers, Kristel; Bäumer, Veerle; Maes, Githa; Corsmit, Ellen; Cruts, Marc; Van Broeckhoven, Christine; van der Zee, Julie; Gijselinck, Ilse; Dillen, Lubina; Van Langenhove, Tim; Philtjens, Stéphanie; Theuns, Jessie; Sleegers, Kristel; Bäumer, Veerle; Maes, Githa; Cruts, Marc; Van Broeckhoven, Christine; Engelborghs, Sebastiaan; De Deyn, Peter P; Cras, Patrick; Engelborghs, Sebastiaan; De Deyn, Peter P; Vandenbulcke, Mathieu; Vandenbulcke, Mathieu; Borroni, Barbara; Padovani, Alessandro; Archetti, Silvana; Perneczky, Robert; Diehl-Schmid, Janine; Synofzik, Matthis; Maetzler, Walter; Müller Vom Hagen, Jennifer; Schöls, Ludger; Synofzik, Matthis; Maetzler, Walter; Müller Vom Hagen, Jennifer; Schöls, Ludger; Heneka, Michael T; Jessen, Frank; Ramirez, Alfredo; Kurzwelly, Delia; Sachtleben, Carmen; Mairer, Wolfgang; de Mendonça, Alexandre; Miltenberger-Miltenyi, Gabriel; Pereira, Sónia; Firmo, Clara; Pimentel, José; Sanchez-Valle, Raquel; Llado, Albert; Antonell, Anna; Molinuevo, Jose; Gelpi, Ellen; Graff, Caroline; Chiang, Huei-Hsin; Westerlund, Marie; Graff, Caroline; Kinhult Ståhlbom, Anne; Thonberg, Håkan; Nennesmo, Inger; Börjesson-Hanson, Anne; Nacmias, Benedetta; Bagnoli, Silvia; Sorbi, Sandro; Bessi, Valentina; Piaceri, Irene; Santana, Isabel; Santiago, Beatriz; Santana, Isabel; Helena Ribeiro, Maria; Rosário Almeida, Maria; Oliveira, Catarina; Massano, João; Garret, Carolina; Pires, Paula; Frisoni, Giovanni; Zanetti, Orazio; Bonvicini, Cristian; Sarafov, Stayko; Tournev, Ivailo; Jordanova, Albena; Tournev, Ivailo; Kovacs, Gabor G; Ströbel, Thomas; Heneka, Michael T; Jessen, Frank; Ramirez, Alfredo; Kurzwelly, Delia; Sachtleben, Carmen; Mairer, Wolfgang; Jessen, Frank; Matej, Radoslav; Parobkova, Eva; Danel, Adrian; Arzberger, Thomas; Maria Fabrizi, Gian; Testi, Silvia; Ferrari, Sergio; Cavallaro, Tiziana; Salmon, Eric; Santens, Patrick; Cras, Patrick

    2013-02-01

    We assessed the geographical distribution of C9orf72 G(4) C(2) expansions in a pan-European frontotemporal lobar degeneration (FTLD) cohort (n = 1,205), ascertained by the European Early-Onset Dementia (EOD) consortium. Next, we performed a meta-analysis of our data and that of other European studies, together 2,668 patients from 15 Western European countries. The frequency of the C9orf72 expansions in Western Europe was 9.98% in overall FTLD, with 18.52% in familial, and 6.26% in sporadic FTLD patients. Outliers were Finland and Sweden with overall frequencies of respectively 29.33% and 20.73%, but also Spain with 25.49%. In contrast, prevalence in Germany was limited to 4.82%. In addition, we studied the role of intermediate repeats (7-24 repeat units), which are strongly correlated with the risk haplotype, on disease and C9orf72 expression. In vitro reporter gene expression studies demonstrated significantly decreased transcriptional activity of C9orf72 with increasing number of normal repeat units, indicating that intermediate repeats might act as predisposing alleles and in favor of the loss-of-function disease mechanism. Further, we observed a significantly increased frequency of short indels in the GC-rich low complexity sequence adjacent to the G(4) C(2) repeat in C9orf72 expansion carriers (P < 0.001) with the most common indel creating one long contiguous imperfect G(4) C(2) repeat, which is likely more prone to replication slippage and pathological expansion. PMID:23111906

  1. A pan-European study of the C9orf72 repeat associated with FTLD: geographic prevalence, genomic instability, and intermediate repeats.

    PubMed

    van der Zee, Julie; Gijselinck, Ilse; Dillen, Lubina; Van Langenhove, Tim; Theuns, Jessie; Engelborghs, Sebastiaan; Philtjens, Stéphanie; Vandenbulcke, Mathieu; Sleegers, Kristel; Sieben, Anne; Bäumer, Veerle; Maes, Githa; Corsmit, Ellen; Borroni, Barbara; Padovani, Alessandro; Archetti, Silvana; Perneczky, Robert; Diehl-Schmid, Janine; de Mendonça, Alexandre; Miltenberger-Miltenyi, Gabriel; Pereira, Sónia; Pimentel, José; Nacmias, Benedetta; Bagnoli, Silvia; Sorbi, Sandro; Graff, Caroline; Chiang, Huei-Hsin; Westerlund, Marie; Sanchez-Valle, Raquel; Llado, Albert; Gelpi, Ellen; Santana, Isabel; Almeida, Maria Rosário; Santiago, Beatriz; Frisoni, Giovanni; Zanetti, Orazio; Bonvicini, Cristian; Synofzik, Matthis; Maetzler, Walter; Vom Hagen, Jennifer Müller; Schöls, Ludger; Heneka, Michael T; Jessen, Frank; Matej, Radoslav; Parobkova, Eva; Kovacs, Gabor G; Ströbel, Thomas; Sarafov, Stayko; Tournev, Ivailo; Jordanova, Albena; Danek, Adrian; Arzberger, Thomas; Fabrizi, Gian Maria; Testi, Silvia; Salmon, Eric; Santens, Patrick; Martin, Jean-Jacques; Cras, Patrick; Vandenberghe, Rik; De Deyn, Peter Paul; Cruts, Marc; Van Broeckhoven, Christine; van der Zee, Julie; Gijselinck, Ilse; Dillen, Lubina; Van Langenhove, Tim; Theuns, Jessie; Philtjens, Stéphanie; Sleegers, Kristel; Bäumer, Veerle; Maes, Githa; Corsmit, Ellen; Cruts, Marc; Van Broeckhoven, Christine; van der Zee, Julie; Gijselinck, Ilse; Dillen, Lubina; Van Langenhove, Tim; Philtjens, Stéphanie; Theuns, Jessie; Sleegers, Kristel; Bäumer, Veerle; Maes, Githa; Cruts, Marc; Van Broeckhoven, Christine; Engelborghs, Sebastiaan; De Deyn, Peter P; Cras, Patrick; Engelborghs, Sebastiaan; De Deyn, Peter P; Vandenbulcke, Mathieu; Vandenbulcke, Mathieu; Borroni, Barbara; Padovani, Alessandro; Archetti, Silvana; Perneczky, Robert; Diehl-Schmid, Janine; Synofzik, Matthis; Maetzler, Walter; Müller Vom Hagen, Jennifer; Schöls, Ludger; Synofzik, Matthis; Maetzler, Walter; Müller Vom Hagen, Jennifer; Schöls, Ludger; Heneka, Michael T; Jessen, Frank; Ramirez, Alfredo; Kurzwelly, Delia; Sachtleben, Carmen; Mairer, Wolfgang; de Mendonça, Alexandre; Miltenberger-Miltenyi, Gabriel; Pereira, Sónia; Firmo, Clara; Pimentel, José; Sanchez-Valle, Raquel; Llado, Albert; Antonell, Anna; Molinuevo, Jose; Gelpi, Ellen; Graff, Caroline; Chiang, Huei-Hsin; Westerlund, Marie; Graff, Caroline; Kinhult Ståhlbom, Anne; Thonberg, Håkan; Nennesmo, Inger; Börjesson-Hanson, Anne; Nacmias, Benedetta; Bagnoli, Silvia; Sorbi, Sandro; Bessi, Valentina; Piaceri, Irene; Santana, Isabel; Santiago, Beatriz; Santana, Isabel; Helena Ribeiro, Maria; Rosário Almeida, Maria; Oliveira, Catarina; Massano, João; Garret, Carolina; Pires, Paula; Frisoni, Giovanni; Zanetti, Orazio; Bonvicini, Cristian; Sarafov, Stayko; Tournev, Ivailo; Jordanova, Albena; Tournev, Ivailo; Kovacs, Gabor G; Ströbel, Thomas; Heneka, Michael T; Jessen, Frank; Ramirez, Alfredo; Kurzwelly, Delia; Sachtleben, Carmen; Mairer, Wolfgang; Jessen, Frank; Matej, Radoslav; Parobkova, Eva; Danel, Adrian; Arzberger, Thomas; Maria Fabrizi, Gian; Testi, Silvia; Ferrari, Sergio; Cavallaro, Tiziana; Salmon, Eric; Santens, Patrick; Cras, Patrick

    2013-02-01

    We assessed the geographical distribution of C9orf72 G(4) C(2) expansions in a pan-European frontotemporal lobar degeneration (FTLD) cohort (n = 1,205), ascertained by the European Early-Onset Dementia (EOD) consortium. Next, we performed a meta-analysis of our data and that of other European studies, together 2,668 patients from 15 Western European countries. The frequency of the C9orf72 expansions in Western Europe was 9.98% in overall FTLD, with 18.52% in familial, and 6.26% in sporadic FTLD patients. Outliers were Finland and Sweden with overall frequencies of respectively 29.33% and 20.73%, but also Spain with 25.49%. In contrast, prevalence in Germany was limited to 4.82%. In addition, we studied the role of intermediate repeats (7-24 repeat units), which are strongly correlated with the risk haplotype, on disease and C9orf72 expression. In vitro reporter gene expression studies demonstrated significantly decreased transcriptional activity of C9orf72 with increasing number of normal repeat units, indicating that intermediate repeats might act as predisposing alleles and in favor of the loss-of-function disease mechanism. Further, we observed a significantly increased frequency of short indels in the GC-rich low complexity sequence adjacent to the G(4) C(2) repeat in C9orf72 expansion carriers (P < 0.001) with the most common indel creating one long contiguous imperfect G(4) C(2) repeat, which is likely more prone to replication slippage and pathological expansion.

  2. DNA Triplet Repeat Expansion and Mismatch Repair

    PubMed Central

    Iyer, Ravi R.; Pluciennik, Anna; Napierala, Marek; Wells, Robert D.

    2016-01-01

    DNA mismatch repair is a conserved antimutagenic pathway that maintains genomic stability through rectification of DNA replication errors and attenuation of chromosomal rearrangements. Paradoxically, mutagenic action of mismatch repair has been implicated as a cause of triplet repeat expansions that cause neurological diseases such as Huntington disease and myotonic dystrophy. This mutagenic process requires the mismatch recognition factor MutSβ and the MutLα (and/or possibly MutLγ) endonuclease, and is thought to be triggered by the transient formation of unusual DNA structures within the expanded triplet repeat element. This review summarizes the current knowledge of DNA mismatch repair involvement in triplet repeat expansion, which encompasses in vitro biochemical findings, cellular studies, and various in vivo transgenic animal model experiments. We present current mechanistic hypotheses regarding mismatch repair protein function in mediating triplet repeat expansions and discuss potential therapeutic approaches targeting the mismatch repair pathway. PMID:25580529

  3. The Moral Maturity of Repeater Delinquents.

    ERIC Educational Resources Information Center

    Petronio, Richard J.

    1980-01-01

    Differences in moral development (as conceived by Kohlberg) were examined in a sample of delinquent teenagers. The repeater group was not found, as had been hypothesized, to be lower on moral maturity than those who engaged in less delinquency. (GC)

  4. Repeat hepatectomy for colorectal liver metastases.

    PubMed Central

    Adam, R; Bismuth, H; Castaing, D; Waechter, F; Navarro, F; Abascal, A; Majno, P; Engerran, L

    1997-01-01

    OBJECTIVE: The authors assess the long-term results of repeat hepatectomies for recurrent metastases of colorectal cancer and determine the factors that can predict survival. SUMMARY BACKGROUND DATA: Safer techniques of hepatic resection have allowed surgeons to consider repeat hepatectomy for colorectal metastases in an increasing number of patients. However, higher operative bleeding and increased morbidity have been reported after repeat hepatectomies, and the long-term benefit of these procedures needs to be evaluated. STUDY POPULATION: Sixty-four patients from a group of 243 patients resected for colorectal liver metastases were submitted to 83 repeat hepatectomies (64 second, 15 third, and 4 fourth hepatectomies). Combined extrahepatic surgery was performed in 21 (25%) of these 83 repeat hepatectomies. RESULTS: There was no intraoperative or postoperative mortality. Operative bleeding was not significantly increased in repeat hepatectomies as compared to first resections. Morbidity and duration of hospital stay were comparable to first hepatectomies. Overall and disease-free survival after a second hepatectomy were 60% and 42%, respectively, at 3 years and 41% and 26%, respectively, at 5 years. Factors of prognostic value on univariate analysis included the curative nature of first and second hepatectomies (p = 0.04 and p = 0.002, respectively), an interval between the two procedures of more than 1 year (p = 0.003), the number of recurrent tumors (p = 0.002), serum carcinoembryonic antigen levels (p = 0.03), and the presence of extrahepatic disease (p = 0.03). Only the curative nature of the second hepatectomy and an interval of more than 1 year between the two procedures were independently related to survival on multivariate analysis. CONCLUSIONS: Repeat hepatectomies can provide long-term survival rates similar to those of first hepatectomies, with no mortality and comparable morbidity. Combined extrahepatic surgery can be required to achieve tumor

  5. Star repeaters for fiber optic links.

    PubMed

    McMahon, D H; Gravel, R L

    1977-02-01

    A star repeater combines the functions of a passive star coupler and a signal regenerating amplifier. By more effectively utilizing the light power radiated by a light emitting diode, the star repeater can, when used with small diameter channels, couple as much power to all receivers of a multiterminal link as would be coupled to the single receiver of a simple point-to-point link.

  6. Linear analysis of active-medium two-beam accelerator

    NASA Astrophysics Data System (ADS)

    Voin, Miron; Schächter, Levi

    2015-07-01

    We present detailed development of the linear theory of wakefield amplification by active medium and its possible application to a two-beam accelerator (TBA) is discussed. A relativistic train of triggering microbunches traveling along a vacuum channel in an active medium confined by a cylindrical waveguide excites Cherenkov wake in the medium. The wake is a superposition of azimuthally symmetric transverse magnetic modes propagating along a confining waveguide, with a phase velocity equal to the velocity of the triggering bunches. The structure may be designed in such a way that the frequency of one of the modes is close to active-medium resonant frequency, resulting in amplification of the former and domination of a single mode far behind the trigger bunches. Another electron bunch placed in proper phase with the amplified wakefield may be accelerated by the latter. Importantly, the energy for acceleration is provided by the active medium and not the drive bunch as in a traditional TBA. Based on a simplified model, we analyze extensively the impact of various parameters on the wakefield amplification process.

  7. Digital repeat analysis; setup and operation.

    PubMed

    Nol, J; Isouard, G; Mirecki, J

    2006-06-01

    Since the emergence of digital imaging, there have been questions about the necessity of continuing reject analysis programs in imaging departments to evaluate performance and quality. As a marketing strategy, most suppliers of digital technology focus on the supremacy of the technology and its ability to reduce the number of repeats, resulting in less radiation doses given to patients and increased productivity in the department. On the other hand, quality assurance radiographers and radiologists believe that repeats are mainly related to positioning skills, and repeat analysis is the main tool to plan training needs to up-skill radiographers. A comparative study between conventional and digital imaging was undertaken to compare outcomes and evaluate the need for reject analysis. However, digital technology still being at its early development stages, setting a credible reject analysis program became the major task of the study. It took the department, with the help of the suppliers of the computed radiography reader and the picture archiving and communication system, over 2 years of software enhancement to build a reliable digital repeat analysis system. The results were supportive of both philosophies; the number of repeats as a result of exposure factors was reduced dramatically; however, the percentage of repeats as a result of positioning skills was slightly on the increase for the simple reason that some rejects in the conventional system qualifying for both exposure and positioning errors were classified as exposure error. The ability of digitally adjusting dark or light images reclassified some of those images as positioning errors. PMID:16421768

  8. Structures of designed armadillo-repeat proteins show propagation of inter-repeat interface effects.

    PubMed

    Reichen, Christian; Madhurantakam, Chaithanya; Hansen, Simon; Grütter, Markus G; Plückthun, Andreas; Mittl, Peer R E

    2016-01-01

    The armadillo repeat serves as a scaffold for the development of modular peptide-recognition modules. In order to develop such a system, three crystal structures of designed armadillo-repeat proteins with third-generation N-caps (YIII-type), four or five internal repeats (M-type) and second-generation C-caps (AII-type) were determined at 1.8 Å (His-YIIIM4AII), 2.0 Å (His-YIIIM5AII) and 1.95 Å (YIIIM5AII) resolution and compared with those of variants with third-generation C-caps. All constructs are full consensus designs in which the internal repeats have exactly the same sequence, and hence identical conformations of the internal repeats are expected. The N-cap and internal repeats M1 to M3 are indeed extremely similar, but the comparison reveals structural differences in internal repeats M4 and M5 and the C-cap. These differences are caused by long-range effects of the C-cap, contacting molecules in the crystal, and the intrinsic design of the repeat. Unfortunately, the rigid-body movement of the C-terminal part impairs the regular arrangement of internal repeats that forms the putative peptide-binding site. The second-generation C-cap improves the packing of buried residues and thereby the stability of the protein. These considerations are useful for future improvements of an armadillo-repeat-based peptide-recognition system. PMID:26894544

  9. Frequency doubled, cavity dumped feedback laser

    NASA Technical Reports Server (NTRS)

    Sipes, Jr., Donald L. (Inventor); Robinson, Deborah L. (Inventor)

    1989-01-01

    Higher efficiency in cavity dumping and frequency doubling in a laser used to produce modulated output beam pulses is achieved by deflecting light out of the resonant cavity to a third mirror through a frequency doubler using an electro-optic modulator and a polarizing beamsplitter in the resonant cavity, or using just an acousto-optic modulator to deflect light out of the laser cavity in response to a control signal (electric or acoustic). The frequency doubler in front of the third mirror rotates the frequency doubled light so that it will pass out of the laser cavity through the polarizing beamsplitter, while undoubled frequency light is reflected by the polarizing beamsplitter back into the gain medium of the laser. In the case of using a type-II frequency doubler, a dichroic beamsplitter deflects out the frequency doubled light and passes the undoubled frequency light to the polarizing beamsplitter for return to the laser gain medium. If an acousto-optic modulator is used, it deflects light out of the primary laser cavity, so a polarizing beamsplitter is not needed, and only a dichroic beamsplitter is needed to separate frequency doubled light out of the path from the third mirror.

  10. Antibodies reactive to Plasmodium falciparum serine repeat antigen in children with Burkitt lymphoma from Ghana.

    PubMed

    Guech-Ongey, Mercy; Yagi, Masanori; Palacpac, Nirianne Marie Q; Emmanuel, Benjamin; Talisuna, Ambrose O; Bhatia, Kishor; Stefan, D Cristina; Biggar, Robert J; Nkrumah, Francis; Neequaye, Janet; Tougan, Takahiro; Horii, Toshihiro; Mbulaiteye, Sam M

    2012-04-15

    The role of protective immunity to Plasmodium falciparum (Pf) malaria in Burkitt lymphoma (BL) is unknown. We investigated the association between BL and antibodies reactive to SE36 antigen, a recombinant protein based on P. falciparum serine repeat antigen 5 gene, targeted by protective malaria immune responses. Cases were children (0-14 years) enrolled at the Korle-Bu Teaching Hospital, Accra, Ghana, during 1965-1994 with BL confirmed by histology or cytology (92% of cases). Controls were apparently healthy children enrolled contemporaneous to the cases from the nearest neighbor house to the case house and were age,- sex-frequency-matched to the cases. Anti-SE36 IgG antibodies were measured using enzyme-linked absorbent immunoassays (ELISAs). SE36 titers were estimated by extrapolating ELISA optical density readings to a standard fitting curve. Anti-SE36 titers were log-transformed for analysis. Odds ratios (ORs) and two-sided 95% confidence intervals (95% CIs) were estimated using unconditional logistic regression. The mean log endpoint dilution titers were 0.63 logs lower in cases than in controls (8.26 [SD 1.68] vs. 8.89 [SD 1.75], Student's t-test, p = 0.019). Lower titers were observed in cases than controls aged 0-4 years (p = 0.05) and in those aged 5-14 years (p = 0.06). Low and medium tertiles of anti-SE36 IgG antibodies were associated with increased OR for BL ([OR 1.67, 95% CI 1.21-2.31] and [OR 1.33, 95% CI 0.96-1.86], respectively, p(trend) = 0.002) in analyses adjusting for age, sex, calendar period and test plate. Our findings suggest that compared to similarly aged children enrolled from the same community, children with BL in Ghana have lower antibodies to SE36 antigen. PMID:21630256

  11. Incidence, complexity and diversity of simple sequence repeats across potexvirus genomes.

    PubMed

    Alam, Chaudhary Mashhood; Singh, Avadhesh Kumar; Sharfuddin, Choudhary; Ali, Safdar

    2014-03-10

    An in-silico analysis of simple sequence repeats (SSRs) in genomes of 32 species of potexviruses was performed wherein a total of 691 SSRs and 33 cSSRs were observed. Though SSRs were present in all the studied genomes their incident frequency ranged from 11 to 30 per genome. Further, 10 potexvirus genomes possessed no cSSRs when extracted at a dMAX of 10 and wherein present, the highest frequency was 3. SSR and cSSR incidence, relative density and relative abundance were non-significantly correlated with genome size and GC content suggesting an ongoing evolutionary and adaptive phase of the virus species. SSRs present primarily ranged from mono- to tri-nucleotide repeat motifs with a greatly skewed distribution across the coding and non-coding regions. Present work is an effort for the undergoing compilation and analysis of incidence, distribution and variation of the viral repeat sequences to understand their evolutionary and functional relevance.

  12. Low abundance of microsatellite repeats in the genome of the Brown-headed Cowbird (Molothrus ater)

    USGS Publications Warehouse

    Longmire, J.L.; Hahn, D.C.; Roach, J.L.

    1999-01-01

    A cosmid library made from brown-headed cowbird (Molothrus ater) DNA was examined for representation of 17 distinct microsatellite motifs including all possible mono-, di-, and trinucleotide microsatellites, and the tetranucleotide repeat (GATA)n. The overall density of microsatellites within cowbird DNA was found to be one repeat per 89 kb and the frequency of the most abundant motif, (AGC)n, was once every 382 kb. The abundance of microsatellites within the cowbird genome is estimated to be reduced approximately 15-fold compared to humans. The reduced frequency of microsatellites seen in this study is consistent with previous observations indicating reduced numbers of microsatellites and other interspersed repeats in avian DNA. In addition to providing new information concerning the abundance of microsatellites within an avian genome, these results provide useful insights for selecting cloning strategies that might be used in the development of locus-specific microsatellite markers for avian studies.

  13. Repeated sequences in bacterial chromosomes and plasmids: a glimpse from sequenced genomes.

    PubMed

    Romero, D; Martínez-Salazar, J; Ortiz, E; Rodríguez, C; Valencia-Morales, E

    1999-01-01

    To gain insight into the extent of exact DNA repeats in sequenced bacterial genomes and their plasmids, we analyzed the collection of completely sequenced bacterial genomes available at GenBank using the program Miropeats. This program draws graphical representations of exact DNA repeats in whole genomes. In this work, we present maps showing the extent and type (inverted or direct) of exact DNA repeats longer than 300 bp for the whole collection. These repeats may participate in a variety of events relevant for bacterial genome plasticity, such as amplifications, deletions, inversions, and translocations (via homologous recombination), as well as transposition. Additionally, we review recent data showing that high-frequency architectural variations in genomic structure occur at both the interspecies and interstrain levels.

  14. Depressive Symptoms and Violence Exposure: Contributors to Repeat Pregnancies Among Adolescents

    PubMed Central

    Anderson, Cheryl A.; Pierce, Lisa

    2015-01-01

    ABSTRACT Depressive symptoms and violence exposure (VE) often cooccur and have been recognized to influence childbearing; contribution to repeat pregnancy is unclear and examined in this article. This cross-sectional, descriptive, study screened for depressive symptoms and VE among 193 adolescent mothers at a large county hospital in Southwestern United States. Repeat pregnancy and depressive symptoms characterized one-third and one-quarter of adolescents, respectively. Despite minimal disclosure of VE, repeat pregnancy was significantly influenced by child abuse and past traumatic life experiences. Assessments and interventions with adolescents should focus on frequency of repeat pregnancies and symptoms of depression and VE. Nurses and childbirth educators are poised to offer birth control information and education, support, and resources highlighting depression and VE to adolescents. PMID:26834444

  15. Composite medium with simultaneously negative permeability and permittivity

    PubMed

    Smith; Padilla; Vier; Nemat-Nasser; Schultz

    2000-05-01

    We demonstrate a composite medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous wires, that exhibits a frequency region in the microwave regime with simultaneously negative values of effective permeability &mgr;(eff)(omega) and permittivity varepsilon(eff)(omega). This structure forms a "left-handed" medium, for which it has been predicted that such phenomena as the Doppler effect, Cherenkov radiation, and even Snell's law are inverted. It is now possible through microwave experiments to test for these effects using this new metamaterial. PMID:10990641

  16. Composite Medium with Simultaneously Negative Permeability and Permittivity

    SciTech Connect

    Smith, D. R.; Padilla, Willie J.; Vier, D. C.; Nemat-Nasser, S. C.; Schultz, S.

    2000-05-01

    We demonstrate a composite medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous wires, that exhibits a frequency region in the microwave regime with simultaneously negative values of effective permeability {mu}{sub eff}({omega}) and permittivity {epsilon}{sub eff}({omega}) . This structure forms a ''left-handed'' medium, for which it has been predicted that such phenomena as the Doppler effect, Cherenkov radiation, and even Snell's law are inverted. It is now possible through microwave experiments to test for these effects using this new metamaterial. (c) 2000 The American Physical Society.

  17. Slow convergence to effective medium in finite discrete metamaterials

    NASA Astrophysics Data System (ADS)

    Lapine, M.; McPhedran, R. C.; Poulton, C. G.

    2016-06-01

    It is known that metamaterial properties may differ significantly from the predictions of effective-medium theory. In many cases this is due to the finite size and discrete structure, which cannot be neglected in practical samples with a relatively small amount of elements. We analyze the response of finite discrete metamaterial objects of a spherical shape and demonstrate the role of boundary effects in these structures, pointing out an interplay between the size of the structure and the dissipation. We conclude that the discrepancy between the actual resonance frequency of a sphere and the effective-medium prediction is inversely proportional to the size of the sphere.

  18. Active microwave remote sensing of an anisotropic random medium layer

    NASA Technical Reports Server (NTRS)

    Lee, J. K.; Kong, J. A.

    1985-01-01

    A two-layer anisotropic random medium model has been developed to study the active remote sensing of the earth. The dyadic Green's function for a two-layer anisotropic medium is developed and used in conjunction with the first-order Born approximation to calculate the backscattering coefficients. It is shown that strong cross-polarization occurs in the single scattering process and is indispensable in the interpretation of radar measurements of sea ice at different frequencies, polarizations, and viewing angles. The effects of anisotropy on the angular responses of backscattering coefficients are also illustrated.

  19. Refractive scintillation in the interstellar medium

    NASA Astrophysics Data System (ADS)

    Coles, W. A.; Rickett, B. J.; Codona, J. L.; Frehlich, R. G.

    1987-04-01

    The slow variation in the apparent intensity of pulsars on time scales of days to months was recently shown to be due to a large-scale component of interstellar scintillation (Rickett, Coles, and Bourgois). These variations are greater than one would expect if the turbulence spectrum were a simple Kolmogorov power law. It is shown that this large-scale component can be greatly enhanced when the turbulence spectrum has a limiting "inner scale" of the order of 109m. The authors present a solution for the covariance of refractive scintillation of an extended source in an extended medium. The results show that refractive scintillations are also responsible for slow variations in "low-frequency variables".

  20. Turkish population data with the CODIS multiplex short tandem repeat loci.

    PubMed

    Akbasak, B S; Budowle, B; Reeder, D J; Redman, J; Kline, M C

    2001-12-01

    Allele frequencies for 13 tetrameric short tandem repeat (STR) loci, CSF1PO, D18S51, D3S1358, D21S11, D5S818, FGA, D7S820, HUMTH01, D8S1179, TPOX, D13S317, VWA, and D16S539 were determined on 198 Turkish blood samples.

  1. About wave field modeling in hierarchic medium with fractal inclusions

    NASA Astrophysics Data System (ADS)

    Hachay, Olga; Khachay, Andrey

    2014-05-01

    The processes of oil gaseous deposits outworking are linked with moving of polyphase multicomponent media, which are characterized by no equilibrium and nonlinear rheological features. The real behavior of layered systems is defined as complicated rheology moving liquids and structural morphology of porous media. It is eargently needed to account those factors for substantial description of the filtration processes. Additionally we must account also the synergetic effects. That allows suggesting new methods of control and managing of complicated natural systems, which can research these effects. Thus our research is directed to the layered system, from which we have to outwork oil and which is a complicated hierarchic dynamical system with fractal inclusions. In that paper we suggest the algorithm of modeling of 2-d seismic field distribution in the heterogeneous medium with hierarchic inclusions. Also we can compare the integral 2-D for seismic field in a frame of local hierarchic heterogeneity with a porous inclusion and pure elastic inclusion for the case when the parameter Lame is equal to zero for the inclusions and the layered structure. For that case we can regard the problem for the latitude and longitudinal waves independently. Here we shall analyze the first case. The received results can be used for choosing criterions of joined seismic methods for high complicated media research.If the boundaries of the inclusion of the k rank are fractals, the surface and contour integrals in the integral equations must be changed to repeated fractional integrals of Riman-Liuvill type .Using the developed earlier 3-d method of induction electromagnetic frequency geometric monitoring we showed the opportunity of defining of physical and structural features of hierarchic oil layer structure and estimating of water saturating by crack inclusions. For visualization we had elaborated some algorithms and programs for constructing cross sections for two hierarchic structural

  2. Tissue culture triggers chromosome alterations, amplification, and transposition of repeat sequences in Allium fistulosum.

    PubMed

    Gernand, Dorota; Golczyk, Hieronim; Rutten, Twan; Ilnicki, Tomasz; Houben, Andreas; Joachimiak, Andrzej J

    2007-05-01

    Structural alterations in nuclei and chromosomes of cells derived from callus culture of Allium fistulosum have been studied with fluorescent in situ hybridization (FISH) using 5S ribosomal DNA (rDNA), 45S rDNA, and 375-bp repeat probes. A high frequency of chromosome abnormalities was found to be caused by the loss of telomere-located 375-bp repeats, chromosome fusion, and subsequent breakage-fusion-bridge cycles. Products of chromosome fusions and monocentric and regularly shaped chromosomes showed additional 375-bp repeat and 45S rDNA clusters at unusual sites, suggesting dynamic copy-number changes and transposition of these repeats. Southern hybridization revealed no differences in the 375-bp repeat and 45S rDNA repeat array order or the degree of methylation between DNA isolated from leaves or tissue-culture cells. In addition, protruding, spike-like structures positive for 375-bp repeats were identified on the surface of different-sized nuclei. Transmission electron microscopy analysis revealed the accumulation of densely packed chromatin within spike-like structures. Because root calyptra cells showed similar structures, it is likely that heterochromatic spike-like structures are a feature of nondividing cells at the onset of programmed cell death. PMID:17612612

  3. Differential distribution and occurrence of simple sequence repeats in diverse geminivirus genomes.

    PubMed

    George, B; Mashhood Alam, Ch; Jain, S K; Sharfuddin, Ch; Chakraborty, S

    2012-12-01

    Microsatellites are tandem repeat sequences with repeat unit of one to six base pairs. Although, microsatellites have been studied in eukaryotes as well as prokaryotes, information on their occurrence on virus genomes is limited. We examined microsatellite distribution in 263 complete geminivirus genomes. Results indicated microsatellites to be an important component of geminiviral genomes. For each geminiviral genome, mono- and dinucleotide repeats were found to be highly predominant. Occurrence of microsatellites within geminiviral genome is significantly lesser than organisms with higher genome sizes and their number decreased with an increase in the length of repeat unit. Repeats of AT/TA, GT/TG, CT/TC, CTT/TTC, and GAA/AAG occurred with high frequency, whereas CG/GC, CGA/AGC, AAC/CAA, and GCT/TCG repeats had rare incidence. Interesting observation related to differential distribution of simple sequence repeats in genomic components of begomoviruses has been noted. We discussed the possible reasons for the observed divergence. To our knowledge, this is the first analysis of microsatellites occurring in any ssDNA viral genome for such purposes and represents a general approach for analysis of other viral genomes. The presence of microsatellites in geminiviral genomes may be used to obtain information regarding viral genetic diversity, evolution, and strain (isolate) identification.

  4. Stalled DNA Replication Forks at the Endogenous GAA Repeats Drive Repeat Expansion in Friedreich's Ataxia Cells.

    PubMed

    Gerhardt, Jeannine; Bhalla, Angela D; Butler, Jill Sergesketter; Puckett, James W; Dervan, Peter B; Rosenwaks, Zev; Napierala, Marek

    2016-08-01

    Friedreich's ataxia (FRDA) is caused by the expansion of GAA repeats located in the Frataxin (FXN) gene. The GAA repeats continue to expand in FRDA patients, aggravating symptoms and contributing to disease progression. The mechanism leading to repeat expansion and decreased FXN transcription remains unclear. Using single-molecule analysis of replicated DNA, we detected that expanded GAA repeats present a substantial obstacle for the replication machinery at the FXN locus in FRDA cells. Furthermore, aberrant origin activation and lack of a proper stress response to rescue the stalled forks in FRDA cells cause an increase in 3'-5' progressing forks, which could enhance repeat expansion and hinder FXN transcription by head-on collision with RNA polymerases. Treatment of FRDA cells with GAA-specific polyamides rescues DNA replication fork stalling and alleviates expansion of the GAA repeats, implicating DNA triplexes as a replication impediment and suggesting that fork stalling might be a therapeutic target for FRDA.

  5. Stalled DNA Replication Forks at the Endogenous GAA Repeats Drive Repeat Expansion in Friedreich's Ataxia Cells.

    PubMed

    Gerhardt, Jeannine; Bhalla, Angela D; Butler, Jill Sergesketter; Puckett, James W; Dervan, Peter B; Rosenwaks, Zev; Napierala, Marek

    2016-08-01

    Friedreich's ataxia (FRDA) is caused by the expansion of GAA repeats located in the Frataxin (FXN) gene. The GAA repeats continue to expand in FRDA patients, aggravating symptoms and contributing to disease progression. The mechanism leading to repeat expansion and decreased FXN transcription remains unclear. Using single-molecule analysis of replicated DNA, we detected that expanded GAA repeats present a substantial obstacle for the replication machinery at the FXN locus in FRDA cells. Furthermore, aberrant origin activation and lack of a proper stress response to rescue the stalled forks in FRDA cells cause an increase in 3'-5' progressing forks, which could enhance repeat expansion and hinder FXN transcription by head-on collision with RNA polymerases. Treatment of FRDA cells with GAA-specific polyamides rescues DNA replication fork stalling and alleviates expansion of the GAA repeats, implicating DNA triplexes as a replication impediment and suggesting that fork stalling might be a therapeutic target for FRDA. PMID:27425605

  6. Elastic Waves Green Functions For Stratified Medium

    NASA Astrophysics Data System (ADS)

    Albuquerque, E. L.; Ferreira, E. C.; Mauriz, P. W.

    Multiple scattering analysis of elastic waves propagating in a stratified medium is a powerful method to model seismic reflection signals, widely used in the exploration for oil and gas reservoirs. Reflection imaging and inversion method derive their exis- tence from the presence of singularities in the Earth's material properties that support the waves. Considering a Green's function formalism based on the {it frequency distri- bution} of the elastic wave spectra, we study their propagation within a model in which the Earth is treated as a stratified medium. The calculations are based on the linear response function approach, which is very convenient to deal with this kind of prob- lem. Both the displacement ({it space}) and the wavevector ({it space-time}) Green's functions are determined. A damping term gamma is included in a phenomenolog- ical way into the wavevector expression. In order to examine the waves' excitation, we also determine, by using the fluctuation-dissipation theorem, their power spectra, which have many interesting properties.

  7. Automated genotyping of dinucleotide repeat markers

    SciTech Connect

    Perlin, M.W.; Hoffman, E.P. |

    1994-09-01

    The dinucleotide repeats (i.e., microsatellites) such as CA-repeats are a highly polymorphic, highly abundant class of PCR-amplifiable markers that have greatly streamlined genetic mapping experimentation. It is expected that over 30,000 such markers (including tri- and tetranucleotide repeats) will be characterized for routine use in the next few years. Since only size determination, and not sequencing, is required to determine alleles, in principle, dinucleotide repeat genotyping is easily performed on electrophoretic gels, and can be automated using DNA sequencers. Unfortunately, PCR stuttering with these markers generates not one band for each allele, but a pattern of bands. Since closely spaced alleles must be disambiguated by human scoring, this poses a key obstacle to full automation. We have developed methods that overcome this obstacle. Our model is that the observed data is generated by arithmetic superposition (i.e., convolution) of multiple allele patterns. By quantitatively measuring the size of each component band, and exploiting the unique stutter pattern associated with each marker, closely spaced alleles can be deconvolved; this unambiguously reconstructs the {open_quotes}true{close_quotes} allele bands, with stutter artifact removed. We used this approach in a system for automated diagnosis of (X-linked) Duchenne muscular dystrophy; four multiplexed CA-repeats within the dystrophin gene were assayed on a DNA sequencer. Our method accurately detected small variations in gel migration that shifted the allele size estimate. In 167 nonmutated alleles, 89% (149/167) showed no size variation, 9% (15/167) showed 1 bp variation, and 2% (3/167) showed 2 bp variation. We are currently developing a library of dinucleotide repeat patterns; together with our deconvolution methods, this library will enable fully automated genotyping of dinucleotide repeats from sizing data.

  8. Modeling flow in a pressure-sensitive, heterogeneous medium

    SciTech Connect

    Vasco, Donald W.; Minkoff, Susan E.

    2009-06-01

    Using an asymptotic methodology, including an expansion in inverse powers of {radical}{omega}, where {omega} is the frequency, we derive a solution for flow in a medium with pressure dependent properties. The solution is valid for a heterogeneous medium with smoothly varying properties. That is, the scale length of the heterogeneity must be significantly larger then the scale length over which the pressure increases from it initial value to its peak value. The resulting asymptotic expression is similar in form to the solution for pressure in a medium in which the flow properties are not functions of pressure. Both the expression for pseudo-phase, which is related to the 'travel time' of the transient pressure disturbance, and the expression for pressure amplitude contain modifications due to the pressure dependence of the medium. We apply the method to synthetic and observed pressure variations in a deforming medium. In the synthetic test we model one-dimensional propagation in a pressure-dependent medium. Comparisons with both an analytic self-similar solution and the results of a numerical simulation indicate general agreement. Furthermore, we are able to match pressure variations observed during a pulse test at the Coaraze Laboratory site in France.

  9. Properties of the nuclear medium.

    PubMed

    Baldo, M; Burgio, G F

    2012-02-01

    We review our knowledge on the properties of the nuclear medium that have been studied, over many years, on the basis of many-body theory, laboratory experiments and astrophysical observations. Throughout the presentation particular emphasis is placed on the possible relationship and links between the nuclear medium and the structure of nuclei, including the limitations of such an approach. First we consider the realm of phenomenological laboratory data and astrophysical observations and the hints they can give on the characteristics that the nuclear medium should possess. The analysis is based on phenomenological models, that however have a strong basis on physical intuition and an impressive success. More microscopic models are also considered, and it is shown that they are able to give invaluable information on the nuclear medium, in particular on its equation of state. The interplay between laboratory experiments and astrophysical observations is particularly stressed, and it is shown how their complementarity enormously enriches our insights into the structure of the nuclear medium. We then introduce the nucleon-nucleon interaction and the microscopic many-body theory of nuclear matter, with a critical discussion about the different approaches and their results. The Landau-Fermi liquid theory is introduced and briefly discussed, and it is shown how fruitful it can be in discussing the macroscopic and low-energy properties of the nuclear medium. As an illustrative example, we discuss neutron matter at very low density, and it is shown how it can be treated within the many-body theory. The general bulk properties of the nuclear medium are reviewed to indicate at which stage of our knowledge we stand, taking into account the most recent developments both in theory and experiments. A section is dedicated to the pairing problem. The connection with nuclear structure is then discussed, on the basis of the energy density functional method. The possibility of linking

  10. Properties of the nuclear medium

    NASA Astrophysics Data System (ADS)

    Baldo, M.; Burgio, G. F.

    2012-02-01

    We review our knowledge on the properties of the nuclear medium that have been studied, over many years, on the basis of many-body theory, laboratory experiments and astrophysical observations. Throughout the presentation particular emphasis is placed on the possible relationship and links between the nuclear medium and the structure of nuclei, including the limitations of such an approach. First we consider the realm of phenomenological laboratory data and astrophysical observations and the hints they can give on the characteristics that the nuclear medium should possess. The analysis is based on phenomenological models, that however have a strong basis on physical intuition and an impressive success. More microscopic models are also considered, and it is shown that they are able to give invaluable information on the nuclear medium, in particular on its equation of state. The interplay between laboratory experiments and astrophysical observations is particularly stressed, and it is shown how their complementarity enormously enriches our insights into the structure of the nuclear medium. We then introduce the nucleon-nucleon interaction and the microscopic many-body theory of nuclear matter, with a critical discussion about the different approaches and their results. The Landau-Fermi liquid theory is introduced and briefly discussed, and it is shown how fruitful it can be in discussing the macroscopic and low-energy properties of the nuclear medium. As an illustrative example, we discuss neutron matter at very low density, and it is shown how it can be treated within the many-body theory. The general bulk properties of the nuclear medium are reviewed to indicate at which stage of our knowledge we stand, taking into account the most recent developments both in theory and experiments. A section is dedicated to the pairing problem. The connection with nuclear structure is then discussed, on the basis of the energy density functional method. The possibility of linking

  11. Shared selective pressure and local genomic landscape lead to repeatable patterns of genomic divergence in sunflowers.

    PubMed

    Renaut, Sebastien; Owens, Gregory L; Rieseberg, Loren H

    2014-02-01

    The repeated evolution of traits in organisms facing similar environmental conditions is considered to be fundamental evidence for the role of natural selection in moulding phenotypes. Yet, aside from case studies of parallel evolution and its genetic basis, the repeatability of evolution at the level of the whole genome remains poorly characterized. Here, through the use of transcriptome sequencing, we examined genomic divergence for three pairs of sister species of sunflowers. Two of the pairs (Helianthus petiolaris - H. debilis and H. annuus - H. argophyllus) have diverged along a similar latitudinal gradient and presumably experienced similar selective pressure. In contrast, a third species pair (H. exilis - H. bolanderi) diverged along a longitudinal gradient. Analyses of divergence, as measured in terms of FST, indicated little repeatability across the three pairs of species for individual genetic markers (SNPs), modest repeatability at the level of individual genes and the highest repeatability when large regions of the genome were compared. As expected, higher repeatability was observed for the two species pairs that have diverged along a similar latitudinal gradient, with genes involved in flowering time among the most divergent genes. Genes showing extreme low or high differentiation were more similar than genes showing medium levels of divergence, implying that both purifying and divergent selection contributed to repeatable patterns of divergence. The location of a gene along the chromosome also predicted divergence levels, presumably because of shared heterogeneity in both recombination and mutation rates. In conclusion, repeated genome evolution appeared to result from both similar selective pressures and shared local genomic landscapes.

  12. Variable efficacy of repeated annual influenza vaccination.

    PubMed

    Smith, D J; Forrest, S; Ackley, D H; Perelson, A S

    1999-11-23

    Conclusions have differed in studies that have compared vaccine efficacy in groups receiving influenza vaccine for the first time to efficacy in groups vaccinated more than once. For example, the Hoskins study [Hoskins, T. W., Davis, J. R., Smith, A. J., Miller, C. L. & Allchin, A. (1979) Lancet i, 33-35] concluded that repeat vaccination was not protective in the long term, whereas the Keitel study [Keitel, W. A., Cate, T. R., Couch, R. B., Huggins, L. L. & Hess, K. R. (1997) Vaccine 15, 1114-1122] concluded that repeat vaccination provided continual protection. We propose an explanation, the antigenic distance hypothesis, and test it by analyzing seven influenza outbreaks that occurred during the Hoskins and Keitel studies. The hypothesis is that variation in repeat vaccine efficacy is due to differences in antigenic distances among vaccine strains and between the vaccine strains and the epidemic strain in each outbreak. To test the hypothesis, antigenic distances were calculated from historical hemagglutination inhibition assay tables, and a computer model of the immune response was used to predict the vaccine efficacy of individuals given different vaccinations. The model accurately predicted the observed vaccine efficacies in repeat vaccinees relative to the efficacy in first-time vaccinees (correlation 0.87). Thus, the antigenic distance hypothesis offers a parsimonious explanation of the differences between and within the Hoskins and Keitel studies. These results have implications for the selection of influenza vaccine strains, and also for vaccination strategies for other antigenically variable pathogens that might require repeated vaccination. PMID:10570188

  13. Variable efficacy of repeated annual influenza vaccination.

    PubMed

    Smith, D J; Forrest, S; Ackley, D H; Perelson, A S

    1999-11-23

    Conclusions have differed in studies that have compared vaccine efficacy in groups receiving influenza vaccine for the first time to efficacy in groups vaccinated more than once. For example, the Hoskins study [Hoskins, T. W., Davis, J. R., Smith, A. J., Miller, C. L. & Allchin, A. (1979) Lancet i, 33-35] concluded that repeat vaccination was not protective in the long term, whereas the Keitel study [Keitel, W. A., Cate, T. R., Couch, R. B., Huggins, L. L. & Hess, K. R. (1997) Vaccine 15, 1114-1122] concluded that repeat vaccination provided continual protection. We propose an explanation, the antigenic distance hypothesis, and test it by analyzing seven influenza outbreaks that occurred during the Hoskins and Keitel studies. The hypothesis is that variation in repeat vaccine efficacy is due to differences in antigenic distances among vaccine strains and between the vaccine strains and the epidemic strain in each outbreak. To test the hypothesis, antigenic distances were calculated from historical hemagglutination inhibition assay tables, and a computer model of the immune response was used to predict the vaccine efficacy of individuals given different vaccinations. The model accurately predicted the observed vaccine efficacies in repeat vaccinees relative to the efficacy in first-time vaccinees (correlation 0.87). Thus, the antigenic distance hypothesis offers a parsimonious explanation of the differences between and within the Hoskins and Keitel studies. These results have implications for the selection of influenza vaccine strains, and also for vaccination strategies for other antigenically variable pathogens that might require repeated vaccination.

  14. Measurement of soil water content with dielectric dispersion frequency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Frequency domain reflectometry (FDR) is an inexpensive and attractive methodology for repeated measurements of soil water content (SWC). Although there are some known measurement limitations for dry soil and sand, a fixed-frequency method is commonly employed using commercially available FDR probes....

  15. Explaining the gender difference in nightmare frequency.

    PubMed

    Schredl, Michael

    2014-01-01

    A recent meta-analysis showed a robust gender difference in nightmare frequency of medium effect size in adolescents and young adults: Women tend to report nightmares more frequently than men. The present study, carried out in an unselected student sample, indicates that 2 factors mediate the gender difference in nightmare frequency: neuroticism and overall dream recall frequency. The effect of neuroticism on the gender difference and the finding that the gender difference in nightmare frequency emerges at an age of about 10 years suggest that gender-specific socialization processes may play an important role in explaining the gender differences in nightmare frequency in adolescents and young to middle-aged adults. This idea is supported by the previous finding that nightmare frequency is related to sex role orientation. However, longitudinal studies are necessary to validate these hypotheses. PMID:24934011

  16. Rate analysis for a hybrid quantum repeater

    SciTech Connect

    Bernardes, Nadja K.; Loock, Peter van

    2011-01-15

    We present a detailed rate analysis for a hybrid quantum repeater assuming perfect memories and using optimal probabilistic entanglement generation and deterministic swapping routines. The hybrid quantum repeater protocol is based on atomic qubit-entanglement distribution through optical coherent-state communication. An exact, analytical formula for the rates of entanglement generation in quantum repeaters is derived, including a study on the impacts of entanglement purification and multiplexing strategies. More specifically, we consider scenarios with as little purification as possible and we show that for sufficiently low local losses, such purifications are still more powerful than multiplexing. In a possible experimental scenario, our hybrid system can create near-maximally entangled (F=0.98) pairs over a distance of 1280 km at rates of the order of 100 Hz.

  17. Do gamma-ray burst sources repeat?

    NASA Technical Reports Server (NTRS)

    Meegan, Charles A.; Hartmann, Dieter H.; Brainerd, J. J.; Briggs, Michael S.; Paciesas, William S.; Pendleton, Geoffrey; Kouveliotou, Chryssa; Fishman, Gerald; Blumenthal, George; Brock, Martin

    1995-01-01

    The demonstration of repeated gamma-ray bursts from an individual source would severely constrain burst source models. Recent reports (Quashnock and Lamb, 1993; Wang and Lingenfelter, 1993) of evidence for repetition in the first BATSE burst catalog have generated renewed interest in this issue. Here, we analyze the angular distribution of 585 bursts of the second BATSE catalog (Meegan et al., 1994). We search for evidence of burst recurrence using the nearest and farthest neighbor statistic and the two-point angular correlation function. We find the data to be consistent with the hypothesis that burst sources do not repeat; however, a repeater fraction of up to about 20% of the observed bursts cannot be excluded.

  18. Quantum Cascade Laser Frequency Combs

    NASA Astrophysics Data System (ADS)

    Faist, Jérôme; Villares, Gustavo; Scalari, Giacomo; Rösch, Markus; Bonzon, Christopher; Hugi, Andreas; Beck, Mattias

    2016-06-01

    It was recently demonstrated that broadband quantum cascade lasers can operate as frequency combs. As such, they operate under direct electrical pumping at both mid-infrared and THz frequencies, making them very attractive for dual-comb spectroscopy. Performance levels are continuously improving, with average powers over 100mW and frequency coverage of 100 cm-1 in the mid-infrared region. In the THz range, 10mW of average power and 600 GHz of frequency coverage are reported. As a result of the very short upper state lifetime of the gain medium, the mode proliferation in these sources arises from four-wave mixing rather than saturable absorption. As a result, their optical output is characterized by the tendency of small intensity modulation of the output power, and the relative phases of the modes to be similar to the ones of a frequency modulated laser. Recent results include the proof of comb operation down to a metrological level, the observation of a Schawlow-Townes broadened linewidth, as well as the first dual-comb spectroscopy measurements. The capability of the structure to integrate monothically nonlinear optical elements as well as to operate as a detector shows great promise for future chip integration of dual-comb systems.

  19. Repeat Gamma Knife Radiosurgery for Trigeminal Neuralgia

    SciTech Connect

    Aubuchon, Adam C.; Chan, Michael D.; Lovato, James F.; Balamucki, Christopher J.; Ellis, Thomas L.; Tatter, Stephen B.; McMullen, Kevin P.; Munley, Michael T.; Deguzman, Allan F.; Ekstrand, Kenneth E.; Bourland, J. Daniel; Shaw, Edward G.

    2011-11-15

    Purpose: Repeat gamma knife stereotactic radiosurgery (GKRS) for recurrent or persistent trigeminal neuralgia induces an additional response but at the expense of an increased incidence of facial numbness. The present series summarized the results of a repeat treatment series at Wake Forest University Baptist Medical Center, including a multivariate analysis of the data to identify the prognostic factors for treatment success and toxicity. Methods and Materials: Between January 1999 and December 2007, 37 patients underwent a second GKRS application because of treatment failure after a first GKRS treatment. The mean initial dose in the series was 87.3 Gy (range, 80-90). The mean retreatment dose was 84.4 Gy (range, 60-90). The dosimetric variables recorded included the dorsal root entry zone dose, pons surface dose, and dose to the distal nerve. Results: Of the 37 patients, 81% achieved a >50% pain relief response to repeat GKRS, and 57% experienced some form of trigeminal dysfunction after repeat GKRS. Two patients (5%) experienced clinically significant toxicity: one with bothersome numbness and one with corneal dryness requiring tarsorraphy. A dorsal root entry zone dose at repeat treatment of >26.6 Gy predicted for treatment success (61% vs. 32%, p = .0716). A cumulative dorsal root entry zone dose of >84.3 Gy (72% vs. 44%, p = .091) and a cumulative pons surface dose of >108.5 Gy (78% vs. 44%, p = .018) predicted for post-GKRS numbness. The presence of any post-GKRS numbness predicted for a >50% decrease in pain intensity (100% vs. 60%, p = .0015). Conclusion: Repeat GKRS is a viable treatment option for recurrent trigeminal neuralgia, although the patient assumes a greater risk of nerve dysfunction to achieve maximal pain relief.

  20. Safety of Repeated Yttrium-90 Radioembolization

    SciTech Connect

    Lam, Marnix G. E. H.; Louie, John D.; Iagaru, Andrei H.; Goris, Michael L.; Sze, Daniel Y.

    2013-10-15

    Purpose: Repeated radioembolization (RE) treatments carry theoretically higher risk of radiation-induced hepatic injury because of the liver's cumulative memory of previous exposure. We performed a retrospective safety analysis on patients who underwent repeated RE. Methods: From 2004 to 2011, a total of 247 patients were treated by RE. Eight patients (5 men, 3 women, age range 51-71 years) underwent repeated treatment of a targeted territory, all with resin microspheres (SIR-Spheres; Sirtex, Lane Cove, Australia). Adverse events were graded during a standardized follow-up. In addition, the correlation between the occurrence of RE-induced liver disease (REILD) and multiple variables was investigated in univariate and multivariate analyses in all 247 patients who received RE. Results: Two patients died shortly after the second treatment (at 84 and 107 days) with signs and symptoms of REILD. Both patients underwent whole liver treatment twice (cumulative doses 3.08 and 2.66 GBq). The other 6 patients demonstrated only minor toxicities after receiving cumulative doses ranging from 2.41 to 3.88 GBq. All patients experienced objective tumor responses. In the whole population, multifactorial analysis identified three risk factors associated with REILD: repeated RE (p = 0.036), baseline serum total bilirubin (p = 0.048), and baseline serum aspartate aminotransferase (p = 0.043). Repeated RE proved to be the only independent risk factor for REILD in multivariate analysis (odds ratio 9.6; p = 0.002). Additionally, the administered activity per target volume (in GBq/L) was found to be an independent risk factor for REILD, but only in whole liver treatments (p = 0.033). Conclusion: The risk of REILD appears to be elevated for repeated RE. Objective tumor responses were observed, but establishment of safety limits will require improvement in dosimetric measurement and prediction.

  1. The puzzle of the triple repeats

    SciTech Connect

    Morell, V.

    1993-06-04

    Two years ago, when researchers discovered the gene that causes a hereditary form of mental retardation known as fragile-X syndrome, they also turned up a mutation so unexpected geneticists are still scratching their heads over it. The defect, which makes genes balloon in size by adding extra copies of a three base-pair repeated sequence of DNA, was the first of its kind. Despite decades of study, nothing like it had ever been seen in any of the species that laid the foundations for modern genetics: bacteria, the fruit fly Drosophila melanogaster, and the mouse. The mutations caused by these expanding trinucleotide repeats turned out be common causes of human disease. In the past 2 years, they have been fingered as the culprits in three hereditary disorders besides fragile-X syndrome: myotronic dystrophy, spinobullar muscular atrophy (also known as Kennedy's disease), and just this March-Huntington's disease. The FMR-1 gene, which is the one at fault in fragile-X syndrome, shows just how much the trinucleotide repeats can expand. The normal gene carries at most 50 copies of the CGG trinucleotide. But in children who inherit the gene from these carriers and actually develop mental retardation and the other fragile-X symptoms, the FMR-1 gene may have hundreds to thousands of CGG repeats. Huge expansions of another trinucleotide repeat (CTG) can also occur from one generation to the next in the gene that causes myotonic dystrophy (DM), while smaller, although no less devastating, expansions in the CAG trinucleotide repeat lead to Huntington's and Kennedy's diseases.

  2. Evaluation of nonlinear frequency compression: Clinical outcomes

    PubMed Central

    Glista, Danielle; Scollie, Susan; Bagatto, Marlene; Seewald, Richard; Parsa, Vijay; Johnson, Andrew

    2009-01-01

    This study evaluated prototype multichannel nonlinear frequency compression (NFC) signal processing on listeners with high-frequency hearing loss. This signal processor applies NFC above a cut-off frequency. The participants were hearing-impaired adults (13) and children (11) with sloping, high-frequency hearing loss. Multiple outcome measures were repeated using a modified withdrawal design. These included speech sound detection, speech recognition, and self-reported preference measures. Group level results provide evidence of significant improvement of consonant and plural recognition when NFC was enabled. Vowel recognition did not change significantly. Analysis of individual results allowed for exploration of individual factors contributing to benefit received from NFC processing. Findings suggest that NFC processing can improve high frequency speech detection and speech recognition ability for adult and child listeners. Variability in individual outcomes related to factors such as degree and configuration of hearing loss, age of participant, and type of outcome measure. PMID:19504379

  3. Large Torque Variations in Two Soft Gamma Repeaters

    NASA Technical Reports Server (NTRS)

    Woods, Peter M.; Kouveliotou, Chryssa; Gogus, Ersin; Finger, Mark H.; Swank, Jean; Markwardt, Craig B.; Hurley, Kevin; vanderKlis, Michiel; Six, N. Frank (Technical Monitor)

    2001-01-01

    We have monitored the pulse frequencies of the two soft gamma repeaters SGR 1806-20 and SGR 1900+14 through the beginning of year 2001 using primarily Rossi X-ray Timing Explorer Proportional Counter Array observations. In both sources, we observe large changes in the spin-down torque up to a factor of approximately 4, which persist for several months. Using long baseline phase-connected timing solutions as well as the overall frequency histories, we construct torque noise power spectra for each SGR. The power spectrum of each source is very red (power-law slope approximately -3.5). These power spectra are consistent in normalization with some accreting systems, yet much steeper in slope than any known accreting source. To the best of our knowledge, torque noise power spectra with a comparably steep frequency dependence have only been seen in young, glitching radio pulsars (e.g. Vela). The observed changes in spin-down rate do not correlate with burst activity, therefore, the physical mechanisms behind each phenomenon are also likely unrelated. Within the context of the magnetar model, seismic activity cannot account for both the bursts and the long-term torque changes unless the seismically active regions are decoupled from one another.

  4. Epigenetic Repeat-Induced Gene Silencing in the Chromosomal and Extrachromosomal Contexts in Human Cells

    PubMed Central

    Mitsuda, Sho-hei; Shimizu, Noriaki

    2016-01-01

    A plasmid bearing both a replication initiation region and a matrix attachment region is spontaneously amplified in transfected mammalian cells and generates plasmid repeats in the extrachromosomal double minutes (DMs) or the chromosomal homogeneously staining region (HSR). Generally, the repeat sequences are subject to repeat-induced gene silencing, the mechanism of which remains to be elucidated. Previous research showed that gene expression from the same plasmid repeat was higher from repeats located at DMs than at the HSR, which may reflect the extrachromosomal environment of the DMs. In the current study, plasmid repeats in both DMs and HSR were associated with repressive histone modifications (H3K9me3, H3K9me2), and the levels of repressive chromatin markers were higher in HSR than in DMs. Inactive chromatin is known to spread to neighboring regions in chromosome arm. Here, we found that such spreading also occurs in extrachromosomal DMs. Higher levels of active histone modifications (H3K9Ac, H3K4me3, and H3K79me2) were detected at plasmid repeats in DMs than in HSR. The level of DNA CpG methylation was generally low in both DMs and HSR; however, there were some hypermethylated copies within the population of repeated sequences, and the frequency of such copies was higher in DMs than in HSR. Together, these data suggest a “DNA methylation-core and chromatin-spread” model for repeat-induced gene silencing. The unique histone modifications at the extrachromosomal context are discussed with regard to the model. PMID:27525955

  5. Epigenetic Repeat-Induced Gene Silencing in the Chromosomal and Extrachromosomal Contexts in Human Cells.

    PubMed

    Mitsuda, Sho-Hei; Shimizu, Noriaki

    2016-01-01

    A plasmid bearing both a replication initiation region and a matrix attachment region is spontaneously amplified in transfected mammalian cells and generates plasmid repeats in the extrachromosomal double minutes (DMs) or the chromosomal homogeneously staining region (HSR). Generally, the repeat sequences are subject to repeat-induced gene silencing, the mechanism of which remains to be elucidated. Previous research showed that gene expression from the same plasmid repeat was higher from repeats located at DMs than at the HSR, which may reflect the extrachromosomal environment of the DMs. In the current study, plasmid repeats in both DMs and HSR were associated with repressive histone modifications (H3K9me3, H3K9me2), and the levels of repressive chromatin markers were higher in HSR than in DMs. Inactive chromatin is known to spread to neighboring regions in chromosome arm. Here, we found that such spreading also occurs in extrachromosomal DMs. Higher levels of active histone modifications (H3K9Ac, H3K4me3, and H3K79me2) were detected at plasmid repeats in DMs than in HSR. The level of DNA CpG methylation was generally low in both DMs and HSR; however, there were some hypermethylated copies within the population of repeated sequences, and the frequency of such copies was higher in DMs than in HSR. Together, these data suggest a "DNA methylation-core and chromatin-spread" model for repeat-induced gene silencing. The unique histone modifications at the extrachromosomal context are discussed with regard to the model. PMID:27525955

  6. Similarities between the target and the intruder in naturally occurring repeated person naming errors

    PubMed Central

    Brédart, Serge; Dardenne, Benoit

    2015-01-01

    The present study investigated an intriguing phenomenon that did not receive much attention so far: repeatedly calling a familiar person with someone else’s name. From participants’ responses to a questionnaire, these repeated naming errors were characterized with respect to a number of properties (e.g., type of names being substituted, error frequency, error longevity) and different features of similarity (e.g., age, gender, type of relationship with the participant, face resemblance and similarity of the contexts of encounter) between the bearer of the target name and the bearer of the wrong name. Moreover, it was evaluated whether the phonological similarity between names, the participants’ age, the difference of age between the two persons whose names were substituted, and face resemblance between the two persons predicted the frequency of error. Regression analyses indicated that phonological similarity between the target name and the wrong name predicted the frequency of repeated person naming errors. The age of the participant was also a significant predictor of error frequency: the older the participant the higher the frequency of errors. Consistent with previous research stressing the importance of the age of acquisition of words on lexical access in speech production, results indicated that bearer of the wrong name was on average known for longer than the bearer of the target name. PMID:26483728

  7. Temporally multiplexed quantum repeaters with atomic gases

    SciTech Connect

    Simon, Christoph; Riedmatten, Hugues de; Afzelius, Mikael

    2010-07-15

    We propose a temporally multiplexed version of the Duan-Lukin-Cirac-Zoller (DLCZ) quantum-repeater protocol using controlled inhomogeneous spin broadening in atomic gases. A first analysis suggests that the advantage of multiplexing is negated by noise due to spin-wave excitations corresponding to unobserved directions of Stokes photon emission. However, this problem can be overcome with the help of a moderate-finesse cavity which is in resonance with Stokes photons, but invisible to the anti-Stokes photons. Our proposal promises greatly enhanced quantum repeater performance with atomic gases.

  8. An alternative bacteriological medium for the isolation of Aeromonas spp.

    USGS Publications Warehouse

    Jenkins, J.A.; Taylor, P.W.

    1995-01-01

    Two solid bacteriologic media were compared for cultivating Aeromonas spp. from piscine sources: the Rimler-Shotts (RS) medium and a starch-glutamate-ampicillin-penicillin-based medium (SGAP-10C) used for the recovery of Aeromonas spp. from water samples. The selective and differential capacities of the media were assessed March through October 1992 by recovery rate and phenotype of 99 isolates representing 15 genera of bacteria. Recovery frequency of Aeromonas spp. (n = 62) was similar at 97% on RS and 95% on SGAP-10C. The SGAP-10C medium proved to be more specific than RS toward Aeromonas species (P ≤ 0.005). Use of SGAP-10C at 24 C for 48 hr offers a better choice for the laboratory recovery of Aeromonas spp. from clinical fish specimens.

  9. Effect of Repeated Evaluation and Repeated Exposure on Acceptability Ratings of Sentences

    ERIC Educational Resources Information Center

    Zervakis, Jennifer; Mazuka, Reiko

    2013-01-01

    This study investigated the effect of repeated evaluation and repeated exposure on grammatical acceptability ratings for both acceptable and unacceptable sentence types. In Experiment 1, subjects in the Experimental group rated multiple examples of two ungrammatical sentence types (ungrammatical binding and double object with dative-only verb),…

  10. Copy number of tandem direct repeats within the inverted repeats of Marek's disease virus DNA.

    PubMed

    Kanamori, A; Nakajima, K; Ikuta, K; Ueda, S; Kato, S; Hirai, K

    1986-12-01

    We previously reported that DNA of the oncogenic strain BC-1 of Marek's disease virus serotype 1 (MDV1) contains three units of tandem direct repeats with 132 base pair (bp) repeats within the inverted repeats of the long regions of the MDV1 genome, whereas the attenuated, nononcogenic viral DNA contains multiple units of tandem direct repeats (Maotani et al., 1986). In the present study, the difference in the copy numbers of 132 bp repeats of oncogenic and nononcogenic MDV1 DNAs in other strains of MDV1 was investigated by Southern blot hybridization. The main copy numbers in different oncogenic MDV1 strains differed: those of BC-1, JM and highly oncogenic Md5 were 3, 5 to 12 and 2, respectively. The viral DNA population with two units of repeats was small, but detectable, in cells infected with either the oncogenic BC-1 or JM strain. The MDV1 DNA in various MD cell lines contained either two units or both two and three units of repeats. The significance of the copy number of repeats in oncogenicity of MDV1 is discussed.

  11. The effective viscosity of a dispersive medium under strain oscillations

    NASA Astrophysics Data System (ADS)

    Fedotovskii, V. S.; Vereshchagina, T. N.

    2015-03-01

    The hydrodynamic dissipative processes that accompany strain oscillations of a dispersive medium with solid spherical inclusions are considered. Based on a simple cell model, the dependence is obtained for the energy dissipation rate, which determines the effective shear viscosity of a suspension under high-frequency strain oscillations. It is shown that the well-known formulas for the effective viscosity should be supplemented with an essential dynamic term depending on the strain oscillation frequency, the inclusion radius, and the viscosity of the liquid.

  12. Frequency synchronization of blue whale calls near Pioneer Seamount.

    PubMed

    Hoffman, Michael D; Garfield, Newell; Bland, Roger W

    2010-07-01

    Vocalizations of blue whales were recorded with a cabled hydrophone array at Pioneer Seamount, 50 miles off the California coast. Most calls occurred in repeated sequences of two-call pairs (A, then B). The B call is a frequency-modulated tone highly repeatable in form and pitch. A model of this sound is described which permits detecting very small frequency shifts. B calls are found to be aligned in frequency to about one part in 180. This requires very fine pitch discrimination and control over calling frequency, and suggests that synchronizing to a common frequency pattern carries some adaptive advantage. Some possibilities for acoustic sensing by whales requiring this fine frequency resolution are discussed. PMID:20649243

  13. Frequency synchronization of blue whale calls near Pioneer Seamount.

    PubMed

    Hoffman, Michael D; Garfield, Newell; Bland, Roger W

    2010-07-01

    Vocalizations of blue whales were recorded with a cabled hydrophone array at Pioneer Seamount, 50 miles off the California coast. Most calls occurred in repeated sequences of two-call pairs (A, then B). The B call is a frequency-modulated tone highly repeatable in form and pitch. A model of this sound is described which permits detecting very small frequency shifts. B calls are found to be aligned in frequency to about one part in 180. This requires very fine pitch discrimination and control over calling frequency, and suggests that synchronizing to a common frequency pattern carries some adaptive advantage. Some possibilities for acoustic sensing by whales requiring this fine frequency resolution are discussed.

  14. Structures of designed armadillo-repeat proteins show propagation of inter-repeat interface effects

    PubMed Central

    Reichen, Christian; Madhurantakam, Chaithanya; Hansen, Simon; Grütter, Markus G.; Plückthun, Andreas; Mittl, Peer R. E.

    2016-01-01

    The armadillo repeat serves as a scaffold for the development of modular peptide-recognition modules. In order to develop such a system, three crystal structures of designed armadillo-repeat proteins with third-generation N-caps (YIII-type), four or five internal repeats (M-type) and second-generation C-caps (AII-type) were determined at 1.8 Å (His-YIIIM4AII), 2.0 Å (His-YIIIM5AII) and 1.95 Å (YIIIM5AII) resolution and compared with those of variants with third-generation C-caps. All constructs are full consensus designs in which the internal repeats have exactly the same sequence, and hence identical conformations of the internal repeats are expected. The N-cap and internal repeats M1 to M3 are indeed extremely similar, but the comparison reveals structural differences in internal repeats M4 and M5 and the C-cap. These differences are caused by long-range effects of the C-cap, contacting molecules in the crystal, and the intrinsic design of the repeat. Unfortunately, the rigid-body movement of the C-terminal part impairs the regular arrangement of internal repeats that forms the putative peptide-binding site. The second-generation C-cap improves the packing of buried residues and thereby the stability of the protein. These considerations are useful for future improvements of an armadillo-repeat-based peptide-recognition system. PMID:26894544

  15. Use of moving interference fringes for holographic recording onto a moving storage medium.

    PubMed

    Tatemichi, H; Yamamoto, M

    1993-07-10

    We describe a feasibility study of a multiplexed holographic recording method onto a moving storage medium by using moving interference fringes caused by diffracted light beams that are generated from an acousto-optic deflector (AOD). The AOD, driven by amplitude-modulated electric signals, generates several diffracted beams with different frequencies because of Doppler shifting by AOD driving-frequency components. The interference between the beams results in a nonstationary light intensity distribution, i.e., a moving interference fringe. Its velocity is reduced by an image-reduction optical system, and the storage medium is moved at the same velocity as the fringe motion at the image-formation point. This compensates for a reduction of visibility with the movement of the medium, so a holographic recording onto a moving medium can be achieved. In addition, angular multiplexing is achieved by switching the AOD driving frequencies. PMID:20829997

  16. Relationship between the transition frequency of local fluid flow and the peak frequency of attenuation

    NASA Astrophysics Data System (ADS)

    Cao, Cheng-Hao; Zhang, Hong-Bing; Pan, Yi-Xin; Teng, Xin-Bao

    2016-03-01

    Local fluid flow (LFF) at the mesoscopic scale is the main dissipation mechanism of seismic waves in heterogeneous porous media within the seismic frequency band. LFF is easily influenced by the structure and boundary conditions of the porous media, which leads to different behaviors of the peak frequency of attenuation. The associated transition frequency can provide detailed information about the trend of LFF; therefore, research on the transition frequency of LFF and its relationship with the peak frequency of the corresponding attenuation (i.e., inverse of quality factor) facilitates the detailed understanding of the effect of inner structures and boundary conditions in porous media. In this study, we firstly obtain the transition frequency of fluid flux based on Biot's theory of poroelasticity and the fast Fourier transform algorithm in a sample containing one repeating unit cell (RUC). We then analyze changes of these two frequencies in porous media with different porous properties. Finally, we extend our analysis to the influence of the undrained boundary condition on the transition frequency and peak frequency in porous media with multiple RUCs. This setup can facilitate the understanding of the effect from the undrained boundary condition. Results demonstrate that these two frequencies have the same trend at low water saturation, but amplitude variations differ between the frequencies as the amount of saturation increases. However, for cases of high water saturation, both the trend and the amplitude variation of these two frequencies fit well with each other.

  17. Testing Multiple Outcomes in Repeated Measures Designs

    ERIC Educational Resources Information Center

    Lix, Lisa M.; Sajobi, Tolulope

    2010-01-01

    This study investigates procedures for controlling the familywise error rate (FWR) when testing hypotheses about multiple, correlated outcome variables in repeated measures (RM) designs. A content analysis of RM research articles published in 4 psychology journals revealed that 3 quarters of studies tested hypotheses about 2 or more outcome…

  18. Triggering of repeating earthquakes in central California

    USGS Publications Warehouse

    Wu, Chunquan; Gomberg, Joan; Ben-Naim, Eli; Johnson, Paul

    2014-01-01

    Dynamic stresses carried by transient seismic waves have been found capable of triggering earthquakes instantly in various tectonic settings. Delayed triggering may be even more common, but the mechanisms are not well understood. Catalogs of repeating earthquakes, earthquakes that recur repeatedly at the same location, provide ideal data sets to test the effects of transient dynamic perturbations on the timing of earthquake occurrence. Here we employ a catalog of 165 families containing ~2500 total repeating earthquakes to test whether dynamic perturbations from local, regional, and teleseismic earthquakes change recurrence intervals. The distance to the earthquake generating the perturbing waves is a proxy for the relative potential contributions of static and dynamic deformations, because static deformations decay more rapidly with distance. Clear changes followed the nearby 2004 Mw6 Parkfield earthquake, so we study only repeaters prior to its origin time. We apply a Monte Carlo approach to compare the observed number of shortened recurrence intervals following dynamic perturbations with the distribution of this number estimated for randomized perturbation times. We examine the comparison for a series of dynamic stress peak amplitude and distance thresholds. The results suggest a weak correlation between dynamic perturbations in excess of ~20 kPa and shortened recurrence intervals, for both nearby and remote perturbations.

  19. Blood Donation by Elderly Repeat Blood Donors

    PubMed Central

    Zeiler, Thomas; Lander-Kox, Jutta; Alt, Timo

    2014-01-01

    Summary Background Upper age limits for blood donors are intended to protect elderly blood donors from donor reactions. However, due to a lack of data about adverse reactions in elderly blood donors, upper age limits are arbitrary and vary considerably between different countries. Methods Here we present data from 171,231 voluntary repeat whole blood donors beyond the age of 68 years. Results Blood donations from repeat blood donors beyond the age of 68 years increased from 2,114 in 2005 to 38,432 in 2012 (from 0,2% to 4.2% of all whole blood donations). Adverse donor reactions in repeat donors decreased with age and were lower than in the whole group (0.26%), even in donors older than 71 years (0.16%). However, from the age of 68 years, the time to complete recovery after donor reactions increased. Donor deferrals were highest in young blood donors (21.4%), but increased again in elderly blood donors beyond 71 years (12.6%). Conclusion Blood donation by regular repeat blood donors older than 71 years may be safely continued. However, due to a lack of data for donors older than 75 years, blood donation in these donors should be handled with great caution. PMID:25254019

  20. Epigenetics and Triplet-Repeat Neurological Diseases

    PubMed Central

    Nageshwaran, Sathiji; Festenstein, Richard

    2015-01-01

    The term “junk DNA” has been reconsidered following the delineation of the functional significance of repetitive DNA regions. Typically associated with centromeres and telomeres, DNA repeats are found in nearly all organisms throughout their genomes. Repetitive regions are frequently heterochromatinized resulting in silencing of intrinsic and nearby genes. However, this is not a uniform rule, with several genes known to require such an environment to permit transcription. Repetitive regions frequently exist as dinucleotide, trinucleotide, and tetranucleotide repeats. The association between repetitive regions and disease was emphasized following the discovery of abnormal trinucleotide repeats underlying spinal and bulbar muscular atrophy (Kennedy’s disease) and fragile X syndrome of mental retardation (FRAXA) in 1991. In this review, we provide a brief overview of epigenetic mechanisms and then focus on several diseases caused by DNA triplet-repeat expansions, which exhibit diverse epigenetic effects. It is clear that the emerging field of epigenetics is already generating novel potential therapeutic avenues for this group of largely incurable diseases. PMID:26733936

  1. Epigenetics and Triplet-Repeat Neurological Diseases.

    PubMed

    Nageshwaran, Sathiji; Festenstein, Richard

    2015-01-01

    The term "junk DNA" has been reconsidered following the delineation of the functional significance of repetitive DNA regions. Typically associated with centromeres and telomeres, DNA repeats are found in nearly all organisms throughout their genomes. Repetitive regions are frequently heterochromatinized resulting in silencing of intrinsic and nearby genes. However, this is not a uniform rule, with several genes known to require such an environment to permit transcription. Repetitive regions frequently exist as dinucleotide, trinucleotide, and tetranucleotide repeats. The association between repetitive regions and disease was emphasized following the discovery of abnormal trinucleotide repeats underlying spinal and bulbar muscular atrophy (Kennedy's disease) and fragile X syndrome of mental retardation (FRAXA) in 1991. In this review, we provide a brief overview of epigenetic mechanisms and then focus on several diseases caused by DNA triplet-repeat expansions, which exhibit diverse epigenetic effects. It is clear that the emerging field of epigenetics is already generating novel potential therapeutic avenues for this group of largely incurable diseases. PMID:26733936

  2. A Structured Group Program for Repeat Dieters.

    ERIC Educational Resources Information Center

    McNamara, Kathleen

    1989-01-01

    Describes a structured group program for women who repeatedly diet and may be at risk of developing more serious eating disorders. Discusses sessions focusing on eating behavior as well as internal factors that contribute to low body esteem and food and weight preoccupation. Evaluates effectiveness of program by self-reports of members of two…

  3. Building Fluency through the Repeated Reading Method

    ERIC Educational Resources Information Center

    Cohen, Joshua

    2011-01-01

    For the last two years the author has used Repeated Reading (RR) to teach reading fluency in English as a Foreign Language classrooms in colleges and universities in Japan. RR is a method where the student reads and rereads a text silently or aloud from two to four times to reach a predetermined level of speed, accuracy, and comprehension. RR…

  4. Longer-baseline telescopes using quantum repeaters.

    PubMed

    Gottesman, Daniel; Jennewein, Thomas; Croke, Sarah

    2012-08-17

    We present an approach to building interferometric telescopes using ideas of quantum information. Current optical interferometers have limited baseline lengths, and thus limited resolution, because of noise and loss of signal due to the transmission of photons between the telescopes. The technology of quantum repeaters has the potential to eliminate this limit, allowing in principle interferometers with arbitrarily long baselines. PMID:23006349

  5. Human adaptation to repeated cold immersions.

    PubMed Central

    Golden, F S; Tipton, M J

    1988-01-01

    1. The present investigation was designed to examine human adaptation to intermittent severe cold exposure and to assess the effect of exercise on any adaptation obtained. 2. Sixteen subjects were divided into two equal groups. Each subject performed ten head-out immersions; two into thermoneutral water which was then cooled until they shivered vigorously, and eight into water at 15 degrees C for 40 min. During the majority of the 15 degrees C immersions, one group (dynamic group) exercised whilst the other (static group) rested. 3. Results showed that both groups responded to repeated cold immersions with a reduction in their initial responses to cold. The time course of these reductions varied, however, between responses. 4. Only the static group developed a reduced metabolic response to prolonged resting immersion. 5. It is concluded that repeated resting exposure to cold was the more effective way of producing an adaptation. The performance of exercise during repeated exposure to cold prevented the development of an adaptive reduction in the metabolic response to cold during a subsequent resting immersion. In addition, many of the adaptations obtained during repeated resting exposure were overridden or masked during a subsequent exercising immersion. PMID:3411500

  6. The Differential Effects of Repeating Kindergarten

    ERIC Educational Resources Information Center

    Burkam, David T.; LoGerfo, Laura; Ready, Doug; Lee, Valerie E.

    2007-01-01

    We use the Early Childhood Longitudinal Study to investigate national patterns addressing (a) who repeats kindergarten, and (b) the subsequent cognitive effects of this event. Using OLS regression techniques, we investigate 1st-time kindergartners who are promoted, 1st-time kindergartners who are retained, and children who are already repeating…

  7. Chlorinated hydrocarbons in women with repeated miscarriages.

    PubMed Central

    Gerhard, I; Daniel, V; Link, S; Monga, B; Runnebaum, B

    1998-01-01

    This study was conducted to investigate a possible etiological role of chlorinated hydrocarbons in the pathogenesis of repeated miscarriages. The blood levels of chlorinated hydrocarbons [CHCs: pentachlorophenol, hexachlorocyclohexane, hexachlorobenzene, the dichlorodiphenyltrichloroethane (DDT) group, polychlorinated biphenyls] were determined in 89 women with repeated miscarriages, who were referred to the University Hospital of Obstetrics and Gynecology of Heidelberg for investigations between 1989 and 1993, and compared to a previously investigated reference population. In more than 20% of the women, at least one of the CHC levels exceeded the reference range. CHC levels did not differ significantly between women with primary or secondary and early or late miscarriages; neither did they differ between women with hormonal or immunological disorders as causes of repeated miscarriages or women with idiopathic repeated miscarriages. No significant associations were detected between CHC levels and further conceptions or the outcome of further pregnancies. As significant associations were found between increasing CHC blood concentrations and immunological and hormonal changes, CHCs may have an impact on the pregnancy course in certain cases. PMID:9755145

  8. Repeat abortions in New York City, 2010.

    PubMed

    Toprani, Amita; Cadwell, Betsy L; Li, Wenhui; Sackoff, Judith; Greene, Carolyn; Begier, Elizabeth

    2015-06-01

    This study aims to describe factors associated with the number of past abortions obtained by New York City (NYC) abortion patients in 2010. We calculated rates of first and repeat abortion by age, race/ethnicity, and neighborhood-level poverty and the mean number of self-reported past abortions by age, race/ethnicity, neighborhood-level poverty, number of living children, education, payment method, marital status, and nativity. We used negative binomial regression to predict number of past abortions by patient characteristics. Of the 76,614 abortions reported for NYC residents in 2010, 57% were repeat abortions. Repeat abortions comprised >50% of total abortions among the majority of sociodemographic groups we examined. Overall, mean number of past abortions was 1.3. Mean number of past abortions was higher for women aged 30-34 years (1.77), women with ≥5 children (2.50), and black non-Hispanic women (1.52). After multivariable regression, age, race/ethnicity, and number of children were the strongest predictors of number of past abortions. This analysis demonstrates that, although socioeconomic disparities exist, all abortion patients are at high risk for repeat unintended pregnancy and abortion. PMID:25779755

  9. History repeats itself: genomic divergence in copepods.

    PubMed

    Renaut, Sébastien; Dion-Côté, Anne-Marie

    2016-04-01

    Press stop, erase everything from now till some arbitrary time in the past and start recording life as it evolves once again. Would you see the same tape of life playing itself over and over, or would a different story unfold every time? The late Steven Jay Gould called this experiment replaying the tape of life and argued that any replay of the tape would lead evolution down a pathway radically different from the road actually taken (Gould 1989). This thought experiment has puzzled evolutionary biologists for a long time: how repeatable are evolutionary events? And if history does indeed repeat itself, what are the factors that may help us predict the path taken? A powerful means to address these questions at a small evolutionary scale is to study closely related populations that have evolved independently, under similar environmental conditions. This is precisely what Pereira et al. (2016) set out to do using marine copepods Tigriopus californicus, and present their results in this issue of Molecular Ecology. They show that evolution can be repeatable and even partly predictable, at least at the molecular level. As expected from theory, patterns of divergence were shaped by natural selection. At the same time, strong genetic drift due to small population sizes also constrained evolution down a similar evolutionary road, and probably contributed to repeatable patterns of genomic divergence. PMID:27012819

  10. Y Se Repite = And It Repeats Itself

    ERIC Educational Resources Information Center

    Katzew, Adriana

    2010-01-01

    In this article, the author discusses Y Se Repite [And It Repeats Itself], a project she conceptualized due to the growing number of Latino/a Mexican migrant workers in dairy farms in the state of Vermont. In 2006, approximately 2,000 Latinos/as--most of them undocumented Mexican migrant workers--worked throughout the state's dairy farms, yet…

  11. Repeater For A Digital-Communication Bus

    NASA Technical Reports Server (NTRS)

    Torres-Guzman, Esteban; Olson, Stephen; Heaps, Tim

    1993-01-01

    Digital repeater circuit designed to extend range of communication on MIL-STD-1553 bus beyond original maximum allowable length of 300 ft. Circuit provides two-way communication, one way at time, and conforms to specifications of MIL-STD-1553. Crosstalk and instability eliminated.

  12. The Effect of Repeaters on Equating

    ERIC Educational Resources Information Center

    Kim, HeeKyoung; Kolen, Michael J.

    2010-01-01

    Test equating might be affected by including in the equating analyses examinees who have taken the test previously. This study evaluated the effect of including such repeaters on Medical College Admission Test (MCAT) equating using a population invariance approach. Three-parameter logistic (3-PL) item response theory (IRT) true score and…

  13. Why Do Students Repeat Admissions Tests?

    ERIC Educational Resources Information Center

    Jones, Martha S.

    Attitudes and beliefs about the admissions process, especially the role of standardized testing in admissions, were examined for students who took a standardized admissions test more than once. Their attitudes were compared with those of students who did not repeat the test. About 200 preveterinary students who had taken the Veterinary Aptitude…

  14. A Repeater in the Language Laboratory

    ERIC Educational Resources Information Center

    Griffiths, B. T.

    1969-01-01

    Discusses the feasilility of the use of repeater devices in the language laboratory in order to enable the student to "recapitulate effortlessly and and indefinitely any utterance of any length which is causing him difficulty or is of special interest. (FWB)

  15. Cumulative Intertrial Inhibition in Repeated Visual Search

    ERIC Educational Resources Information Center

    Takeda, Yuji

    2007-01-01

    In the present study the author examined visual search when the items remain visible across trials but the location of the target varies. Reaction times for inefficient search cumulatively increased with increasing numbers of repeated search trials, suggesting that inhibition for distractors carried over successive trials. This intertrial…

  16. Using dispersive medium to control excitons in 2D materials

    NASA Astrophysics Data System (ADS)

    Klots, Andrey; Bolotin, Kirill I.

    Excitons in 2D materials (2DMs) are known to be sensitive to the surrounding environment. This makes it possible to modify 2D excitons by depositing materials with controlled dielectric constant on top of 2DMs. This possibility becomes especially interesting if we consider materials with dielectric permittivity ɛ that depends both on wavevector k (this happens if the medium is spatially non-uniform) and frequency ω. Here, we develop platforms to control ɛ (k , ω) and explore resulting changes in light-matter interactions of 2DMs. To examine the effect of wavevector-dependent permittivity of the medium, we study absorption/photoluminescence of graphene and MoS2 in the vicinity of highly non-uniform medium - an array of metal nanoparticles, 3-5 nm in diameter. In this case absorption of light can lead to creation of excitons with non-zero momentum. These dark states are not accessible via regular absorption spectroscopy. We study the case of frequency-dependent permittivity by surrounding MoS2 by a highly-dispersive media (e.g. dielectric liquids, graphene and VO2) . We demonstrate non-trivial frequency-dependent renormalization of the quasiparticle bandgap and exciton binding energies.

  17. Long-lasting bradypnea induced by repeated social defeat.

    PubMed

    Brouillard, Charly; Carrive, Pascal; Camus, Françoise; Bénoliel, Jean-Jacques; Similowski, Thomas; Sévoz-Couche, Caroline

    2016-08-01

    Repeated social defeat in the rat induces long-lasting cardiovascular changes associated with anxiety. In this study, we investigated the effects of repeated social defeat on breathing. Respiratory rate was extracted from the respiratory sinus arrhythmia (RSA) peak frequency of the ECG in rats subjected to social defeat for 4 consecutive days. Respiratory rate was recorded under anesthesia 6 days (D+10) or 26 days (D+30) after social defeat. At D+10, defeated (D) rats spent less time in the open arms of the elevated plus maze test, had heavier adrenal glands, and displayed bradypnea, unlike nondefeated animals. At D+30, all signs of anxiety had disappeared. However, one-half of the rats still displayed bradypnea (DL rats, for low respiratory rate indicated by a lower RSA frequency), whereas those with higher respiratory rate (DH rats) had recovered. Acute blockade of the dorsomedial hypothalamus (DMH) or nucleus tractus solitarii (NTS) 5-HT3 receptors reversed bradypnea in all D rats at D+10 and in DL rats at D+30. Respiratory rate was also recorded in conscious animals implanted with radiotelemetric ECG probes. DH rats recovered between D+10 and D+18, whereas DL rats remained bradypneic until D+30. In conclusion, social stress induces sustained chronic bradypnea mediated by DMH neurons and NTS 5-HT3 receptors. These changes are associated with an anxiety-like state that persists until D+10, followed by recovery. However, bradypnea may persist in one-half of the population up until D+30, despite apparent recovery of the anxiety-like state. PMID:27225946

  18. Medium Modification of Vector Mesons

    SciTech Connect

    Chaden Djalali, Michael Paolone, Dennis Weygand, Michael H. Wood, Rakhsha Nasseripour

    2011-03-01

    The theory of the strong interaction, Quantum Chromodynamics (QCD), has been remarkably successful in describing high-energy and short-distance-scale experiments involving quarks and gluons. However, applying QCD to low energy and large-distance scale experiments has been a major challenge. Various QCD-inspired models predict a partial restoration of chiral symmetry in nuclear matter with modifications of the properties of hadrons from their free-space values. Measurable changes such as a shift in mass and/or a change of width are predicted at normal nuclear density. Photoproduction of vector mesons off nuclei have been performed at different laboratories. The properties of the ρ, ω and φ mesons are investigated either directly by measuring their mass spectra or indirectly through transparency ratios. The latest results regarding medium modifications of the vector mesons in the nuclear medium will be discussed.

  19. Medium modifications with recoil polarization

    SciTech Connect

    Brand, J.F.J. van den; Ent, R.

    1994-04-01

    The authors show that the virtual Compton scattering process allows for a precise study of the off-shell electron-nucleon vertex. In a separable model, they show the sensitivity to new unconstrained structure functions of the nucleon, beyond the usual Dirac and Pauli form factors. In addition, they show the sensitivity to bound nucleon form factors using the reaction 4He({rvec e},e{prime},{rvec p}){sup 3}H. A nucleon embedded in a nucleus represents a complex system. Firstly, the bound nucleon is necessarily off-shell and in principle a complete understanding of the dynamical structure of the nucleon is required in order to calculate its off-shell electromagnetic interaction. Secondly, one faces the possibility of genuine medium effects, such as for example quark-exchange contributions. Furthermore, the electromagnetic coupling to the bound nucleon is dependent on the nuclear dynamics through the self-energy of the nucleon in the nuclear medium.

  20. Repeated Use of Gal1 for Gene Disruption in Candida Albicans

    PubMed Central

    Gorman, J. A.; Chan, W.; Gorman, J. W.

    1991-01-01

    A technique which has the potential to allow repeated use of the same selectable marker to create gene disruptions in Candida albicans has been developed. In this approach, originally described for Saccharomyces cerevisiae, the selectable marker is flanked by direct repeats. Mitotic recombination between these repeats leads to elimination of the selectable marker. A module in which the GAL1 gene is flanked by direct repeats of the bacterial CAT gene was constructed and used to disrupt one copy of the URA3 gene in a gal1 mutant. Gal(-) revertants were selected by plating on 2-deoxy-D-galactose (2DOG). The frequency of 2DOG-resistant colonies recovered was 20 times higher than that obtained with a similar construct not flanked by direct repeats. Of these, 20% had lost the GAL1 gene by recombination between the direct repeats. The GAL1 gene was used again to disrupt the remaining wild-type copy of the URA3 gene of one of these gal1 isolates, resulting in a stable ura3 mutant. This technique should be generally applicable to derive homozygous gene disruptions in this diploid organism. PMID:1936958

  1. Induction of osteosarcomas in mouse lumbar vertebrae by repeated external beta-irradiation

    SciTech Connect

    Ootsuyama, A.; Tanooka, H.

    1989-03-15

    Besides skin tumors, osteosarcomas were induced at high frequency in the lumbar vertebrae of ICR mice by repeated local external irradiation of the back with /sup 90/Sr-/sup 90/Y beta-rays when irradiation was repeated three times a week until tumors appeared. The optimum dose range for osteosarcoma induction was 250-350 cGy per exposure at the surface of the back, or 125-175 cGy at the depth of the center of the bone. With the same irradiation schedule, the optimal dose of radiation for induction of osteosarcomas was much lower than that for induction of skin tumors.

  2. An Unstable Trinucleotide-Repeat Region on Chromosome 13 Implicated in Spinocerebellar Ataxia: A Common Expansion Locus

    PubMed Central

    Vincent, John B; Neves-Pereira, Maria L.; Paterson, Andrew D.; Yamamoto, Etsuko; Parikh, Sagar V.; Macciardi, Fabio; Gurling, Hugh M.D.; Potkin, Steve G.; Pato, Carlos N.; Macedo, Antonio; Kovacs, Maria; Davies, Marilyn; Lieberman, Jeffrey A.; Meltzer, Herbert Y.; Petronis, Arturas; Kennedy, James L.

    2000-01-01

    Larger CAG/CTG trinucleotide-repeat tracts in individuals affected with schizophrenia (SCZ) and bipolar affective disorder (BPAD) in comparison with control individuals have previously been reported, implying a possible etiological role for trinucleotide repeats in these diseases. Two unstable CAG/CTG repeats, SEF2-1B and ERDA1, have recently been cloned, and studies indicate that the majority of individuals with large repeats as detected by repeat-expansion detection (RED) have large repeat alleles at these loci. These repeats do not show association of large alleles with either BPAD or SCZ. Using RED, we have identified a BPAD individual with a very large CAG/CTG repeat that is not due to expansion at SEF2-1B or ERDA1. From this individual’s DNA, we have cloned a highly polymorphic trinucleotide repeat consisting of (CTA)n (CTG)n, which is very long (∼1,800 bp) in this patient. The repeat region localizes to chromosome 13q21, within 1.2 cM of fragile site FRA13C. Repeat alleles in our sample were unstable in 13 (5.6%) of 231 meioses. Large alleles (>100 repeats) were observed in 14 (1.25%) of 1,120 patients with psychosis, borderline personality disorder, or juvenile-onset depression and in 5 (.7%) of 710 healthy controls. Very large alleles were also detected for Centre d’Etude Polymorphisme Humaine (CEPH) reference family 1334. This triplet expansion has recently been reported to be the cause of spinocerebellar ataxia type 8 (SCA8); however, none of our large alleles above the disease threshold occurred in individuals either affected by SCA or with known family history of SCA. The high frequency of large alleles at this locus is inconsistent with the much rarer occurrence of SCA8. Thus, it seems unlikely that expansion alone causes SCA8; other genetic mechanisms may be necessary to explain SCA8 etiology. PMID:10712198

  3. 47 CFR 80.1179 - On-board repeater limitations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false On-board repeater limitations. 80.1179 Section... On-board repeater limitations. When an on-board repeater is used, the following limitations must be met: (a) The on-board repeater antenna must be located no higher than 3 meters (10 feet) above...

  4. Frequency-Rank Distributions

    ERIC Educational Resources Information Center

    Brookes, Bertram C.; Griffiths, Jose M.

    1978-01-01

    Frequency, rank, and frequency rank distributions are defined. Extensive discussion on several aspects of frequency rank distributions includes the Poisson process as a means of exploring the stability of ranks; the correlation of frequency rank distributions; and the transfer coefficient, a new measure in frequency rank distribution. (MBR)

  5. Repeated interactions in open quantum systems

    SciTech Connect

    Bruneau, Laurent; Joye, Alain; Merkli, Marco

    2014-07-15

    Analyzing the dynamics of open quantum systems has a long history in mathematics and physics. Depending on the system at hand, basic physical phenomena that one would like to explain are, for example, convergence to equilibrium, the dynamics of quantum coherences (decoherence) and quantum correlations (entanglement), or the emergence of heat and particle fluxes in non-equilibrium situations. From the mathematical physics perspective, one of the main challenges is to derive the irreversible dynamics of the open system, starting from a unitary dynamics of the system and its environment. The repeated interactions systems considered in these notes are models of non-equilibrium quantum statistical mechanics. They are relevant in quantum optics, and more generally, serve as a relatively well treatable approximation of a more difficult quantum dynamics. In particular, the repeated interaction models allow to determine the large time (stationary) asymptotics of quantum systems out of equilibrium.

  6. Overcoming fixation with repeated memory suppression.

    PubMed

    Angello, Genna; Storm, Benjamin C; Smith, Steven M

    2015-01-01

    Fixation (blocks to memories or ideas) can be alleviated not only by encouraging productive work towards a solution, but, as the present experiments show, by reducing counterproductive work. Two experiments examined relief from fixation in a word-fragment completion task. Blockers, orthographically similar negative primes (e.g., ANALOGY), blocked solutions to word fragments (e.g., A_L_ _GY) in both experiments. After priming, but before the fragment completion test, participants repeatedly suppressed half of the blockers using the Think/No-Think paradigm, which results in memory inhibition. Inhibiting blockers did not alleviate fixation in Experiment 1 when conscious recollection of negative primes was not encouraged on the fragment completion test. In Experiment 2, however, when participants were encouraged to remember negative primes at fragment completion, relief from fixation was observed. Repeated suppression may nullify fixation effects, and promote creative thinking, particularly when fixation is caused by conscious recollection of counterproductive information.

  7. Emergence of Fairness in Repeated Group Interactions

    NASA Astrophysics Data System (ADS)

    Van Segbroeck, S.; Pacheco, J. M.; Lenaerts, T.; Santos, F. C.

    2012-04-01

    Often groups need to meet repeatedly before a decision is reached. Hence, most individual decisions will be contingent on decisions taken previously by others. In particular, the decision to cooperate or not will depend on one’s own assessment of what constitutes a fair group outcome. Making use of a repeated N-person prisoner’s dilemma, we show that reciprocation towards groups opens a window of opportunity for cooperation to thrive, leading populations to engage in dynamics involving both coordination and coexistence, and characterized by cycles of cooperation and defection. Furthermore, we show that this process leads to the emergence of fairness, whose level will depend on the dilemma at stake.

  8. Predictability of repeating earthquakes near Parkfield, California

    NASA Astrophysics Data System (ADS)

    Zechar, J. Douglas; Nadeau, Robert M.

    2012-07-01

    We analyse sequences of repeating microearthquakes that were identified by applying waveform coherency methods to data from the Parkfield High-Resolution Seismic Network. Because by definition all events in a sequence have similar magnitudes and locations, the temporal behaviour of these sequences is naturally isolated, which, coupled with the high occurrence rates of small events, makes these data ideal for studying interevent time distributions. To characterize the temporal predictability of these sequences, we perform retrospective forecast experiments using hundreds of earthquakes. We apply three variants of a simple algorithm that produces sequence-specific, time-varying hazard functions, and we find that the sequences are predictable. We discuss limitations of these data and, more generally, challenges in identifying repeating events, and we outline the potential implications of our results for understanding the occurrence of large earthquakes.

  9. Case report: repeated neonaticides in Hokkaido.

    PubMed

    Funayama, M; Ikeda, T; Tabata, N; Azumi, J; Morita, M

    1994-02-01

    Five cases of repeated neonaticides were reported in Hokkaido, the northernmost island of Japan, during the 10 years from 1983 to 1992. Four or more neonates were involved in each case by each mother. All the suspected mothers were not mentally ill. Two of them were single and the rest were married. Each husband was not aware of the pregnancy of his wife, because he was away from home very often. The main motive of murder seemed to be economic and/or to save appearances. Sentences were 1 year penal servitude with a stay of 3 years for one case, but 30-42 months in prison for the other four cases. We rarely find reports of repeated infanticides committed by the same mother in European countries and the United States.

  10. Accumulate-Repeat-Accumulate-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Samuel; Thorpe, Jeremy

    2007-01-01

    Accumulate-repeat-accumulate-accumulate (ARAA) codes have been proposed, inspired by the recently proposed accumulate-repeat-accumulate (ARA) codes. These are error-correcting codes suitable for use in a variety of wireless data-communication systems that include noisy channels. ARAA codes can be regarded as serial turbolike codes or as a subclass of low-density parity-check (LDPC) codes, and, like ARA codes they have projected graph or protograph representations; these characteristics make it possible to design high-speed iterative decoders that utilize belief-propagation algorithms. The objective in proposing ARAA codes as a subclass of ARA codes was to enhance the error-floor performance of ARA codes while maintaining simple encoding structures and low maximum variable node degree.

  11. Interoperability in encoded quantum repeater networks

    NASA Astrophysics Data System (ADS)

    Nagayama, Shota; Choi, Byung-Soo; Devitt, Simon; Suzuki, Shigeya; Van Meter, Rodney

    2016-04-01

    The future of quantum repeater networking will require interoperability between various error-correcting codes. A few specific code conversions and even a generalized method are known, however, no detailed analysis of these techniques in the context of quantum networking has been performed. In this paper we analyze a generalized procedure to create Bell pairs encoded heterogeneously between two separate codes used often in error-corrected quantum repeater network designs. We begin with a physical Bell pair and then encode each qubit in a different error-correcting code, using entanglement purification to increase the fidelity. We investigate three separate protocols for preparing the purified encoded Bell pair. We calculate the error probability of those schemes between the Steane [[7,1,3

  12. High-bandwidth hybrid quantum repeater.

    PubMed

    Munro, W J; Van Meter, R; Louis, Sebastien G R; Nemoto, Kae

    2008-07-25

    We present a physical- and link-level design for the creation of entangled pairs to be used in quantum repeater applications where one can control the noise level of the initially distributed pairs. The system can tune dynamically, trading initial fidelity for success probability, from high fidelity pairs (F=0.98 or above) to moderate fidelity pairs. The same physical resources that create the long-distance entanglement are used to implement the local gates required for entanglement purification and swapping, creating a homogeneous repeater architecture. Optimizing the noise properties of the initially distributed pairs significantly improves the rate of generating long-distance Bell pairs. Finally, we discuss the performance trade-off between spatial and temporal resources.

  13. Quantum repeater with continuous variable encoding

    NASA Astrophysics Data System (ADS)

    Li, Linshu; Albert, Victor V.; Michael, Marios; Muralidharan, Sreraman; Zou, Changling; Jiang, Liang

    2016-05-01

    Quantum communication enables faithful quantum state transfer between different parties and protocols for cryptographic purposes. However, quantum communication over long distances (>1000km) remains challenging due to optical channel attenuation. This calls for investigation on developing novel encoding schemes that correct photon loss errors efficiently. In this talk, we introduce the generalization of multi-component Schrödinger cat states and propose to encode quantum information in these cat states for ultrafast quantum repeaters. We detail the quantum error correction procedures at each repeater station and characterize the performance of this novel encoding scheme given practical imperfections, such as coupling loss. A comparison with other quantum error correcting codes for bosonic modes will be discussed.

  14. Evolution and recombination of bovine DNA repeats.

    PubMed

    Jobse, C; Buntjer, J B; Haagsma, N; Breukelman, H J; Beintema, J J; Lenstra, J A

    1995-09-01

    The history of the abundant repeat elements in the bovine genome has been studied by comparative hybridization and PCR. The Bov-A and Bov-B SINE elements both emerged just after the divergence of the Camelidae and the true ruminants. A 31-bp subrepeat motif in satellites of the Bovidae species cattle, sheep, and goat is also present in Cervidae (deer) and apparently predates the Bovidae. However, the other components of the bovine satellites were amplified after the divergence of the cattle and the Caprinae (sheep and goat). A 23-bp motif, which as subrepeat of two major satellites occupies 5% of the cattle genome, emerged only after the split of the water buffalo and other cattle species. During the evolution of the Bovidae the satellite repeat units were shaped by recombination events involving subrepeats, other satellite components, and SINE elements. Differences in restriction sites of homologous satellites indicate a continuing rapid horizontal spread of new sequence variants.

  15. Intraspecific variation in flight metabolic rate in the bumblebee Bombus impatiens: repeatability and functional determinants in workers and drones.

    PubMed

    Darveau, Charles-A; Billardon, Fannie; Bélanger, Kasandra

    2014-02-15

    The evolution of flight energetics requires that phenotypes be variable, repeatable and heritable. We studied intraspecific variation in flight energetics in order to assess the repeatability of flight metabolic rate and wingbeat frequency, as well as the functional basis of phenotypic variation in workers and drones of the bumblebee species Bombus impatiens. We showed that flight metabolic rate and wingbeat frequency were highly repeatable in workers, even when controlling for body mass variation using residual analysis. We did not detect significant repeatability in drones, but a smaller range of variation might have prevented us from finding significant values in our sample. Based on our results and previous findings, we associated the high repeatability of flight phenotypes in workers to the functional links between body mass, thorax mass, wing size, wingbeat frequency and metabolic rate. Moreover, differences between workers and drones were as predicted from these functional associations, where drones had larger wings for their size, lower wingbeat frequency and lower flight metabolic rate. We also investigated thoracic muscle metabolic phenotypes by measuring the activity of carbohydrate metabolism enzymes, and we found positive correlations between mass-independent metabolic rate and the activity of all enzymes measured, but in workers only. When comparing workers and drones that differ in flight metabolic rate, only the activity of the enzymes hexokinase and trehalase showed the predicted differences. Overall, our study indicates that there should be correlated evolution among physiological phenotypes at multiple levels of organization and morphological traits associated with flight.

  16. Intraspecific variation in flight metabolic rate in the bumblebee Bombus impatiens: repeatability and functional determinants in workers and drones.

    PubMed

    Darveau, Charles-A; Billardon, Fannie; Bélanger, Kasandra

    2014-02-15

    The evolution of flight energetics requires that phenotypes be variable, repeatable and heritable. We studied intraspecific variation in flight energetics in order to assess the repeatability of flight metabolic rate and wingbeat frequency, as well as the functional basis of phenotypic variation in workers and drones of the bumblebee species Bombus impatiens. We showed that flight metabolic rate and wingbeat frequency were highly repeatable in workers, even when controlling for body mass variation using residual analysis. We did not detect significant repeatability in drones, but a smaller range of variation might have prevented us from finding significant values in our sample. Based on our results and previous findings, we associated the high repeatability of flight phenotypes in workers to the functional links between body mass, thorax mass, wing size, wingbeat frequency and metabolic rate. Moreover, differences between workers and drones were as predicted from these functional associations, where drones had larger wings for their size, lower wingbeat frequency and lower flight metabolic rate. We also investigated thoracic muscle metabolic phenotypes by measuring the activity of carbohydrate metabolism enzymes, and we found positive correlations between mass-independent metabolic rate and the activity of all enzymes measured, but in workers only. When comparing workers and drones that differ in flight metabolic rate, only the activity of the enzymes hexokinase and trehalase showed the predicted differences. Overall, our study indicates that there should be correlated evolution among physiological phenotypes at multiple levels of organization and morphological traits associated with flight. PMID:24198266

  17. Electromagnetic field of a charge moving in a chiral isotropic medium.

    PubMed

    Galyamin, Sergey N; Peshkov, Anton A; Tyukhtin, Andrey V

    2013-07-01

    We analyze the electromagnetic field generated by a point charge moving with a constant velocity in an isotropic chiral medium. We work in the frame of the Condon dispersion model for the weak chirality and ultrarelativistic motion of the charge. We show that the field of a moving charge contains two low-frequency wave processes with right- and left-hand circular polarizations and a high-frequency wave process with a right-hand polarization. The low-frequency wave field exists at an arbitrary charge velocity and oscillates at a frequency of the order of the resonant frequency of the medium. This effect is of most importance near the charge trajectory. The high-frequency wave field arises at an ultrahigh velocity and is essential near the plane of charge dislocation for a sufficiently large offset from the trajectory. This wave field oscillates at a frequency that is considerably greater (up to several orders) than the resonant frequency of the medium. Intriguingly, both of these phenomena exist in the domain in front of the charge, thus producing the low- and high-frequency wave forerunners correspondingly.

  18. Repeatability of Response to Asthma Medications

    PubMed Central

    Wu, Ann; Tantisira, Kelan; Li, Lingling; Schuemann, Brooke; Weiss, Scott

    2010-01-01

    Background Pharmacogenetic studies of drug response in asthma assume that patients respond consistently to a treatment but that treatment response varies across patients, however, no formal studies have demonstrated this. Objective To determine the repeatability of commonly used outcomes for treatment response to asthma medications: bronchodilator response, forced expiratory volume in 1 second (FEV1), and provocative concentration of methacholine producing a 20% decline in FEV1 (PC20). Methods The Childhood Asthma Management Program (CAMP) was a multi-center clinical trial of children randomized to receiving budesonide, nedocromil, or placebo. We determined the intraclass correlation coefficient (ICC) for each outcome over repeated visits over four years in CAMP using mixed effects regression models. We adjusted for the covariates: age, race/ethnicity, height, family income, parental education, and symptom score. We incorporated each outcome for each child as repeated outcome measurements and stratified by treatment group. Results The ICC for bronchodilator response was 0.31 in the budesonide group, 0.35 in the nedocromil group, and 0.40 in the placebo group, after adjusting for covariates. The ICC for FEV1 was 0.71 in the budesonide group, 0.60 in the nedocromil group, and 0.69 in the placebo group, after adjusting for covariates. The ICC for PC20 was 0.67 in the budesonide and placebo groups and 0.73 in the nedocromil group, after adjusting for covariates. Conclusion The within treatment group repeatability of FEV1 and PC20 are high; thus these phenotypes are heritable. FEV1 and PC20 may be better phenotypes than bronchodilator response for studies of treatment response in asthma. PMID:19064281

  19. Automatic-repeat-request error control schemes

    NASA Technical Reports Server (NTRS)

    Lin, S.; Costello, D. J., Jr.; Miller, M. J.

    1983-01-01

    Error detection incorporated with automatic-repeat-request (ARQ) is widely used for error control in data communication systems. This method of error control is simple and provides high system reliability. If a properly chosen code is used for error detection, virtually error-free data transmission can be attained. Various types of ARQ and hybrid ARQ schemes, and error detection using linear block codes are surveyed.

  20. A New Property of Repeating Decimals

    ERIC Educational Resources Information Center

    Arledge, Jane; Tekansik, Sarah

    2008-01-01

    As extended by Ginsberg, Midi's theorem says that if the repeated section of a decimal expansion of a prime is split into appropriate blocks and these are added, the result is a string of nines. We show that if the expansion of 1/p[superscript n+1] is treated the same way, instead of being a string of nines, the sum is related to the period of…

  1. Frequency-Dependent Attenuation of Blasting Vibration Waves

    NASA Astrophysics Data System (ADS)

    Zhou, Junru; Lu, Wenbo; Yan, Peng; Chen, Ming; Wang, Gaohui

    2016-10-01

    The dominant frequency, in addition to the peak particle velocity, is a critical factor for assessing adverse effects of the blasting vibration on surrounding structures; however, it has not been fully considered in blasting design. Therefore, the dominant frequency-dependent attenuation mechanism of blast-induced vibration is investigated in the present research. Starting with blasting vibration induced by a spherical charge propagating in an infinite viscoelastic medium, a modified expression of the vibration amplitude spectrum was derived to reveal the frequency dependency of attenuation. Then, ground vibration induced by more complex and more commonly used cylindrical charge that propagates in a semi-infinite viscoelastic medium was analyzed by numerical simulation. Results demonstrate that the absorptive property of the medium results in the frequency attenuation versus distance, whereas a rapid drop or fluctuation occurs during the attenuation of ground vibration. Fluctuation usually appears at moderate to far field, and the dominant frequency generally decreases to half the original value when rapid drop occurs. The decay rate discrepancy between different frequency components and the multimodal structure of vibration spectrum lead to the unsmooth frequency-dependent attenuation. The above research is verified by two field experiments. Furthermore, according to frequency-based vibration standards, frequency drop and fluctuation should be considered when evaluating blast safety. An optimized piecewise assessment is proposed for more accurate evaluation: With the frequency drop point as the breakpoint, the assessment is divided into two independent sections along the propagating path.

  2. Agreement and repeatability of an infrared thermometer.

    PubMed

    Kelechi, Teresa J; Good, Angela; Mueller, Martina

    2011-01-01

    Recently, manufacturers have devised thermometers for home use by patients, such as the TempTouch Infrared Thermometer (TTIR; Diabetica Solutions, San Antonio, TX), which is designed with a long handle that can be used for self-monitoring localized skin temperature of the feet and legs. This study assessed the level of agreement and repeatability of the TTIR compared to a thermistor-type thermometer (TT; PeriFlux, 5020 Temperature Unit, Perimed, Stockholm, Sweden), the reference standard. In 17 healthy subjects, localized skin temperature was measured 8 cm above the right medial malleolus at baseline (Time 1), after a 10-minute rest period (Time 2), and after 10 minutes of cold provocation (Time 3) with a cryotherapy gel wrap placed around the lower legs using the TTIR and TT for temperature measurement. Scatter plots and correlation coefficients showed strong positive relationships between the two measurement methods at all three time points (Time 1: r = 0.95; Time 2: r = 0.97; and, Time 3: r = 0.87). Results showed a reasonable level of agreement between the two methods at Times 1 and 2 but not after cold provocation. Agreement between the methods appears to be better than repeatability within each method. Results for repeatability from both the TT and TTIR were very similar suggesting that there was a systematic bias with increasing temperatures between Time 1 and Time 2.

  3. Genomic Repeat Abundances Contain Phylogenetic Signal

    PubMed Central

    Dodsworth, Steven; Chase, Mark W.; Kelly, Laura J.; Leitch, Ilia J.; Macas, Jiří; Novák, Petr; Piednoël, Mathieu; Weiss-Schneeweiss, Hanna; Leitch, Andrew R.

    2015-01-01

    A large proportion of genomic information, particularly repetitive elements, is usually ignored when researchers are using next-generation sequencing. Here we demonstrate the usefulness of this repetitive fraction in phylogenetic analyses, utilizing comparative graph-based clustering of next-generation sequence reads, which results in abundance estimates of different classes of genomic repeats. Phylogenetic trees are then inferred based on the genome-wide abundance of different repeat types treated as continuously varying characters; such repeats are scattered across chromosomes and in angiosperms can constitute a majority of nuclear genomic DNA. In six diverse examples, five angiosperms and one insect, this method provides generally well-supported relationships at interspecific and intergeneric levels that agree with results from more standard phylogenetic analyses of commonly used markers. We propose that this methodology may prove especially useful in groups where there is little genetic differentiation in standard phylogenetic markers. At the same time as providing data for phylogenetic inference, this method additionally yields a wealth of data for comparative studies of genome evolution. PMID:25261464

  4. Genomic repeat abundances contain phylogenetic signal.

    PubMed

    Dodsworth, Steven; Chase, Mark W; Kelly, Laura J; Leitch, Ilia J; Macas, Jiří; Novák, Petr; Piednoël, Mathieu; Weiss-Schneeweiss, Hanna; Leitch, Andrew R

    2015-01-01

    A large proportion of genomic information, particularly repetitive elements, is usually ignored when researchers are using next-generation sequencing. Here we demonstrate the usefulness of this repetitive fraction in phylogenetic analyses, utilizing comparative graph-based clustering of next-generation sequence reads, which results in abundance estimates of different classes of genomic repeats. Phylogenetic trees are then inferred based on the genome-wide abundance of different repeat types treated as continuously varying characters; such repeats are scattered across chromosomes and in angiosperms can constitute a majority of nuclear genomic DNA. In six diverse examples, five angiosperms and one insect, this method provides generally well-supported relationships at interspecific and intergeneric levels that agree with results from more standard phylogenetic analyses of commonly used markers. We propose that this methodology may prove especially useful in groups where there is little genetic differentiation in standard phylogenetic markers. At the same time as providing data for phylogenetic inference, this method additionally yields a wealth of data for comparative studies of genome evolution.

  5. Repeat Stereotactic Radiosurgery for Acoustic Neuromas

    SciTech Connect

    Kano, Hideyuki; Kondziolka, Douglas; Niranjan, Ajay M.Ch.; Flannery, Thomas J.; Flickinger, John C.; Lunsford, L. Dade

    2010-02-01

    Purpose: To evaluate the outcome of repeat stereotactic radiosurgery (SRS) for acoustic neuromas, we assessed tumor control, clinical outcomes, and the risk of adverse radiation effects in patients whose tumors progressed after initial management. Methods and Materials: During a 21-year experience at our center, 1,352 patients underwent SRS as management for their acoustic neuromas. We retrospectively identified 6 patients who underwent SRS twice for the same tumor. The median patient age was 47 years (range, 35-71 years). All patients had imaging evidence of tumor progression despite initial SRS. One patient also had incomplete surgical resection after initial SRS. All patients were deaf at the time of the second SRS. The median radiosurgery target volume at the time of the initial SRS was 0.5 cc and was 2.1 cc at the time of the second SRS. The median margin dose at the time of the initial SRS was 13 Gy and was 11 Gy at the time of the second SRS. The median interval between initial SRS and repeat SRS was 63 months (range, 25-169 months). Results: At a median follow-up of 29 months after the second SRS (range, 13-71 months), tumor control or regression was achieved in all 6 patients. No patient developed symptomatic adverse radiation effects or new neurological symptoms after the second SRS. Conclusions: With this limited experience, we found that repeat SRS for a persistently enlarging acoustic neuroma can be performed safely and effectively.

  6. Accumulate-Repeat-Accumulate-Accumulate-Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Sam; Thorpe, Jeremy

    2004-01-01

    Inspired by recently proposed Accumulate-Repeat-Accumulate (ARA) codes [15], in this paper we propose a channel coding scheme called Accumulate-Repeat-Accumulate-Accumulate (ARAA) codes. These codes can be seen as serial turbo-like codes or as a subclass of Low Density Parity Check (LDPC) codes, and they have a projected graph or protograph representation; this allows for a high-speed iterative decoder implementation using belief propagation. An ARAA code can be viewed as a precoded Repeat-and-Accumulate (RA) code with puncturing in concatenation with another accumulator, where simply an accumulator is chosen as the precoder; thus ARAA codes have a very fast encoder structure. Using density evolution on their associated protographs, we find examples of rate-lJ2 ARAA codes with maximum variable node degree 4 for which a minimum bit-SNR as low as 0.21 dB from the channel capacity limit can be achieved as the block size goes to infinity. Such a low threshold cannot be achieved by RA or Irregular RA (IRA) or unstructured irregular LDPC codes with the same constraint on the maximum variable node degree. Furthermore by puncturing the accumulators we can construct families of higher rate ARAA codes with thresholds that stay close to their respective channel capacity thresholds uniformly. Iterative decoding simulation results show comparable performance with the best-known LDPC codes but with very low error floor even at moderate block sizes.

  7. Identification of repeat structure in large genomes using repeat probability clouds.

    PubMed

    Gu, Wanjun; Castoe, Todd A; Hedges, Dale J; Batzer, Mark A; Pollock, David D

    2008-09-01

    The identification of repeat structure in eukaryotic genomes can be time-consuming and difficult because of the large amount of information ( approximately 3 x 10(9) bp) that needs to be processed and compared. We introduce a new approach based on exact word counts to evaluate, de novo, the repeat structure present within large eukaryotic genomes. This approach avoids sequence alignment and similarity search, two of the most time-consuming components of traditional methods for repeat identification. Algorithms were implemented to efficiently calculate exact counts for any length oligonucleotide in large genomes. Based on these oligonucleotide counts, oligonucleotide excess probability clouds, or "P-clouds," were constructed. P-clouds are composed of clusters of related oligonucleotides that occur, as a group, more often than expected by chance. After construction, P-clouds were mapped back onto the genome, and regions of high P-cloud density were identified as repetitive regions based on a sliding window approach. This efficient method is capable of analyzing the repeat content of the entire human genome on a single desktop computer in less than half a day, at least 10-fold faster than current approaches. The predicted repetitive regions strongly overlap with known repeat elements as well as other repetitive regions such as gene families, pseudogenes, and segmental duplicons. This method should be extremely useful as a tool for use in de novo identification of repeat structure in large newly sequenced genomes.

  8. Physics of magnetospheric emission in soft gamma-ray repeaters

    NASA Technical Reports Server (NTRS)

    Melia, Fulvio; Fatuzzo, Marco

    1995-01-01

    Soft gamma-ray repeaters appear to be relatively young, strongly magnetized neutron stars embedded within plerions. The observationally inferred presence of teragauss fields and energetic outflows in these sources provides some support for a model in which the bursts results from crustal disturbances that load and energize the magnetosphere with the ensuing generation of sheared Alfven waves. We here determine accurately the structure of the particle efflux and calculate the spectrum of the resultant radiation, incorporating the key effects due to mildly relativistic magnetic bremsstrahlung, a frequency-dependent photospheric radius and angle-dependent boosting of the intensity for emitting elements at different inclinations. We find that the average photospheric radius during the transient event is approximately 4 stellar radii and that the particles attain a Lorentz factor approximately 13.2 by the time the gas becomes optically thin. The calculated spectrum is a weighted integral over the boosted intensity determined from the physical conditions (i.e., magnetic field, particle density, and temperature) at the photospheric radius corresponding to the relevant frequency. When applied to SGR 1806-20, this procedure yields a distance D approximately equals 10 kpc to this source, which appears to be consistent with the range (approximately 8-17 kpc) inferred from its apparent coincidence with the supernova remnant G10.0-0.3.

  9. A Heterogeneous Medium Analytical Benchmark

    SciTech Connect

    Ganapol, B.D.

    1999-09-27

    A benchmark, called benchmark BLUE, has been developed for one-group neutral particle (neutron or photon) transport in a one-dimensional sub-critical heterogeneous plane parallel medium with surface illumination. General anisotropic scattering is accommodated through the Green's Function Method (GFM). Numerical Fourier transform inversion is used to generate the required Green's functions which are kernels to coupled integral equations that give the exiting angular fluxes. The interior scalar flux is then obtained through quadrature. A compound iterative procedure for quadrature order and slab surface source convergence provides highly accurate benchmark qualities (4- to 5- places of accuracy) results.

  10. Medium Effects in Parton Distributions

    SciTech Connect

    William Detmold, Huey-Wen Lin

    2011-12-01

    A defining experiment of high-energy physics in the 1980s was that of the EMC collaboration where it was first observed that parton distributions in nuclei are non-trivially related to those in the proton. This result implies that the presence of the nuclear medium plays an important role and an understanding of this from QCD has been an important goal ever since Here we investigate analogous, but technically simpler, effects in QCD and examine how the lowest moment of the pion parton distribution is modified by the presence of a Bose-condensed gas of pions or kaons.

  11. Low-frequency VLBI in space and interstellar refraction

    SciTech Connect

    Dennison, B.; Booth, R.S.

    1986-08-01

    The proposed orbiting Quasat antenna, equipped with a low-frequency capability (e.g. 327 MHz), would be uniquely suited for studying refractive focusing (slow scintillation) in the interstellar medium, which is suspected of being responsible for at least some apparent low-frequency variability of extragalactic sources. The authors consider in some detail various technical considerations, including the decorrelating effects of the ionosphere and interplanetary medium, and conclude that low-frequency VLBI observations involving Quasat and Earth-based antennas would be feasible, particularly if sources are observed when they are in the anti-solar hemisphere.

  12. Poly: a quantitative analysis tool for simple sequence repeat (SSR) tracts in DNA

    PubMed Central

    Bizzaro, Jeff W; Marx, Kenneth A

    2003-01-01

    Background Simple sequence repeats (SSRs), microsatellites or polymeric sequences are common in DNA and are important biologically. From mononucleotide to trinucleotide repeats and beyond, they can be found in long (> 6 repeating units) tracts and may be characterized by quantifying the frequencies in which they are found and their tract lengths. However, most of the existing computer programs that find SSR tracts do not include these methods. Results A computer program named Poly has been written not only to find SSR tracts but to analyze the results quantitatively. Conclusions Poly is significant in its use of non-standard, quantitative methods of analysis. And, with its flexible object model and data structure, Poly and its generated data can be used for even more sophisticated analyses. PMID:12791171

  13. Repeated-dose liver micronucleus assay: an investigation with 2-nitropropane, a hepatocarcinogen.

    PubMed

    Kawakami, Satoru; Araki, Tetsuro; Nakajima, Mikio; Kusuoka, Osamu; Uchida, Keisuke; Sato, Norihiro; Tanabe, Yoko; Takahashi, Kaori; Wako, Yumi; Kawasako, Kazufumi; Tsurui, Kazuyuki

    2015-03-01

    The utility of the repeated-dose liver micronucleus (RDLMN) assay in the detection of a genotoxic hepatocarcinogen was evaluated. In this paper, a rat hepatocarcinogen, 2-nitropropane (2-NP), was administered orally to young adult rats for 14 and 28 days without a partial hepatectomy or a mitogen, and the micronucleus induction in liver was examined using a simple method to isolate hepatocytes. In addition, a bone marrow micronucleus assay was conducted concomitantly. The frequency of micronucleated hepatocytes induced by 2-NP increased significantly in both the 14- and 28-day repeated-dose studies, while the bone marrow micronucleus assays were negative in each study. These results indicate that the RDLMN assay is useful for detecting a genotoxic hepatocarcinogen that is negative in bone marrow micronucleus assays and is a suitable in vivo genotoxicity test method for integration into a repeated-dose general toxicity study. PMID:25892624

  14. C9ORF72 hexanucleotide repeat expansion in ALS patients from the Central European Russia population.

    PubMed

    Abramycheva, Natalya Y; Lysogorskaia, Elena V; Stepanova, Maria S; Zakharova, Maria N; Kovrazhkina, Elena A; Razinskaya, Olga D; Smirnov, Andrey P; Maltsev, Andrey V; Ustyugov, Alexey A; Kukharsky, Michail S; Khritankova, Inna V; Bachurin, Sergey O; Cooper-Knock, Johnathan; Buchman, Vladimir L; Illarioshkin, Sergey N; Skvortsova, Veronika I; Ninkina, Natalia

    2015-10-01

    Cohorts of amyotrophic lateral sclerosis (ALS) patients and control individuals of Caucasian origin from the Central European Russia (Moscow city and region) were analyzed for the presence of hexanucleotide repeat GGGGCC expansion within the first intron of the C9ORF72 gene. The presence of a large (>40) repeat expansion was found in 15% of familial ALS cases (3 of 20 unrelated familial cases) and 2.5% of sporadic ALS cases (6 of 238) but in none of control cases. These results suggest that the frequency of C9ORF72 hexanucleotide repeats expansions in the Central European Russian ALS patients is significantly lower than in Western European or Northern American ALS patients of Caucasian origin but higher than in Asian ALS patients.

  15. Wave propagation in a strongly heterogeneous elastic porous medium: Homogenization of Biot medium with double porosities

    NASA Astrophysics Data System (ADS)

    Rohan, Eduard; Naili, Salah; Nguyen, Vu-Hieu

    2016-08-01

    We study wave propagation in an elastic porous medium saturated with a compressible Newtonian fluid. The porous network is interconnected whereby the pores are characterized by two very different characteristic sizes. At the mesoscopic scale, the medium is described using the Biot model, characterized by a high contrast in the hydraulic permeability and anisotropic elasticity, whereas the contrast in the Biot coupling coefficient is only moderate. Fluid motion is governed by the Darcy flow model extended by inertia terms and by the mass conservation equation. The homogenization method based on the asymptotic analysis is used to obtain a macroscopic model. To respect the high contrast in the material properties, they are scaled by the small parameter, which is involved in the asymptotic analysis and characterized by the size of the heterogeneities. Using the estimates of wavelengths in the double-porosity networks, it is shown that the macroscopic descriptions depend on the contrast in the static permeability associated with pores and micropores and on the frequency. Moreover, the microflow in the double porosity is responsible for fading memory effects via the macroscopic poroviscoelastic constitutive law. xml:lang="fr"

  16. A model for ultrasound modulated light in a turbid medium

    NASA Astrophysics Data System (ADS)

    Hollmann, Joseph L.; Horstmeyer, Roarke; Yang, Changhuei; DiMarzio, Charles A.

    2014-03-01

    The ability to focus light in most tissue degrades quickly with depth due to high optical scattering. Researchers have investigated using both ultrasound (US) and light synergistically to overcome this difficulty. Ultrasound has been utilized to modulated light within tissue to create a diffusive wave at that is modulated at the US frequency. Recently, there has been interest in the modulated sidebands which reside at optical frequency plus or minus the US frequency. This paper will discuss a model for US-light interactions in a scattering medium. We will use this model to relate the radiance in the probe beam to the radiance in the diffusive wave. We will then employ the P-1 approximation to the radiative transport equation to find the fluence and flux of the modulated wave. We will use these parameters to write a diffusion equation for the modulated wave that can be described in terms of the incoming optical power, and the US intensity and geometry.

  17. Repeated buckling of composite shear panels

    NASA Technical Reports Server (NTRS)

    Singer, Josef; Weller, Tanchum

    1990-01-01

    Failures in service of aerospace structures and research at the Technion Aircraft Structures Laboratory have revealed that repeatedly buckled stiffened shear panels might be susceptible to premature fatigue failures. Extensive experimental and analytical studies have been performed at Technion on repeated buckling, far in excess of initial buckling, for both metal and composite shear panels with focus on the influence of the surrounding structure. The core of the experimental investigation consisted of repeated buckling and postbuckling tests on Wagner beams in a three-point loading system under realistic test conditions. The effects of varying sizes of stiffeners, of the magnitude of initial buckling loads, of the panel aspect ratio and of the cyclic shearing force, V sub cyc, were studied. The cyclic to critical shear buckling ratios, (V sub cyc/V sub cr) were on the high side, as needed for efficient panel design, yet all within possible flight envelopes. The experiments were supplemented by analytical and numerical analyses. For the metal shear panels the test and numerical results were synthesized into prediction formulas, which relate the life of the metal shear panels to two cyclic load parameters. The composite shear panels studied were hybrid beams with graphite/epoxy webs bonded to aluminum alloy frames. The test results demonstrated that composite panels were less fatigue sensitive than comparable metal ones, and that repeated buckling, even when causing extensive damage, did not reduce the residual strength by more than 20 percent. All the composite panels sustained the specified fatigue life of 250,000 cycles. The effect of local unstiffened holes on the durability of repeatedly buckled shear panels was studied for one series of the metal panels. Tests on 2024 T3 aluminum panels with relatively small unstiffened holes in the center of the panels demonstrated premature fatigue failure, compared to panels without holes. Preliminary tests on two graphite

  18. How Does the Medium Affect the Message?

    ERIC Educational Resources Information Center

    Dommermuth, William P.

    1974-01-01

    This experimental comparison of the advertising effectiveness of television, movies, radio, and print finds no support for McLuhan's idea that television is a "cool" medium and movies are a "hot" medium. (RB)

  19. 47 CFR 97.205 - Repeater station.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... geographical coordinates of the antenna (NAD-83 datum), antenna height above mean sea level (AMSL), antenna center of radiation above ground level (AGL), antenna directivity and gain, proposed frequency and...

  20. 47 CFR 97.205 - Repeater station.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... geographical coordinates of the antenna (NAD-83 datum), antenna height above mean sea level (AMSL), antenna center of radiation above ground level (AGL), antenna directivity and gain, proposed frequency and...

  1. A comparison of the original Rappaport medium (R medium) and the Rappaport-Vassiliadis medium (RV medium) in the isolation of salmonellae from meat products.

    PubMed Central

    Vassiliadis, P.; Kalapothaki, V.; Mavrommati, C.; Trichopoulos, D.

    1984-01-01

    The Rappaport-Vassiliadis enrichment medium (RV medium) in 10 ml quantities (RV/43 degrees C, 10 ml) inoculated with 0.1 ml of pre-enrichment medium (P medium) was found more efficient in the isolation of salmonellae from 409 pre-enriched samples (mainly meat products), than the original Rappaport medium incubated at 43 degrees C (R/43 degrees C) and the RV medium in 5 ml quantities (RV/43 degrees C, 5 ml) inoculated with 0.01 ml of P medium (P less than 0.001, in both instances). Therefore, the inoculum from pre-enriched foods should not be less than 0.1 ml in 10 ml of RV medium. The RV/43 degrees, 10 ml was also better (P less than 0.01) in detecting samples containing salmonellas than the original Rappaport medium incubated at 37 degrees C (R/37 degrees C, 10 ml) and the modification R25 of R medium incubated at 37 degrees C. The R25 modification was used in 10 ml quantities (R25/37 degrees C, 10 ml) inoculated with 0.1 ml of P medium and in 5 ml quantities (R25/37 degrees, 5 ml) inoculated with 0.01 ml of P medium. The last two R25 procedures were of the same efficiency in isolating salmonellas from meat products. PMID:6747286

  2. 49 CFR 195.306 - Test medium.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Test medium. 195.306 Section 195.306... PIPELINE Pressure Testing § 195.306 Test medium. (a) Except as provided in paragraphs (b), (c), and (d) of this section, water must be used as the test medium. (b) Except for offshore pipelines,...

  3. 49 CFR 195.306 - Test medium.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Test medium. 195.306 Section 195.306... PIPELINE Pressure Testing § 195.306 Test medium. (a) Except as provided in paragraphs (b), (c), and (d) of this section, water must be used as the test medium. (b) Except for offshore pipelines,...

  4. 49 CFR 195.306 - Test medium.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Test medium. 195.306 Section 195.306... PIPELINE Pressure Testing § 195.306 Test medium. (a) Except as provided in paragraphs (b), (c), and (d) of this section, water must be used as the test medium. (b) Except for offshore pipelines,...

  5. 49 CFR 195.306 - Test medium.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Test medium. 195.306 Section 195.306... PIPELINE Pressure Testing § 195.306 Test medium. (a) Except as provided in paragraphs (b), (c), and (d) of this section, water must be used as the test medium. (b) Except for offshore pipelines,...

  6. 27 CFR 19.914 - Medium plants.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Medium plants. 19.914 Section 19.914 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Medium plants. Any person wishing to establish a medium plant shall make application for and obtain...

  7. 49 CFR 195.306 - Test medium.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Test medium. 195.306 Section 195.306... PIPELINE Pressure Testing § 195.306 Test medium. (a) Except as provided in paragraphs (b), (c), and (d) of this section, water must be used as the test medium. (b) Except for offshore pipelines,...

  8. Utility of consecutive repeat HIT ELISA testing for heparin-induced thrombocytopenia.

    PubMed

    Chan, Maren; Malynn, Elizabeth; Shaz, Beth; Uhl, Lynne

    2008-03-01

    Heparin-induced thrombocytopenia (HIT) is a serious complication of heparin therapy. Limited data are available regarding repeat HIT antibody testing after an initial negative test. We conducted a retrospective study to determine the utility of repeat testing. Heparin antibodies were detected using the GTI-PF4 enzyme-linked immunoabsorbent assay, ELISA (GTI Diagnostics, Waukesha, WI). Patients (n = 137) were assigned to one of three groups based upon the initial negative test optical density (OD) range of low = 0-0.132, medium = 0.133-0.267, and high = 0.268-0.399. A pretest clinical score was retrospectively determined using the "4T's" (Thrombocytopenia, Timing of platelet fall, Thrombosis, and the absence of oTher causes of thrombocytopenia). A subsequent positive ELISA was found in 16% (22/137) of patients who underwent repeat testing. Most of these patients had a low pretest clinical score (62%). Four patients had an interval change in the pretest score between the initial negative and subsequent positive tests. Only these four patients developed HIT with thrombosis (HITT). Eighty percent of patients with a high initial negative test OD value had a positive ELISA on repeat testing; however, the initial negative test OD value could not predict whether a patient developed HITT. In contrast, an increase in the pretest clinical probability between initial and repeat testing better predicted HITT. Consecutive repeat ELISA testing for heparin antibodies may be warranted in patients with an increase in their pretest clinical score after an initial negative test as an adjunct to confirm the diagnosis of HIT.

  9. Smart repeater system for communications interoperability during multi-agency law enforcement operations

    SciTech Connect

    Crutcher, R.I.; Jones, R.W.; Moore, M.R.; Smith, S.F.; Tolley, A.L.; Rochelle, R.W.

    1996-12-31

    A prototype smart repeater that provides interoperability capabilities for radio communication systems in multi-agency and multi-user scenarios is being developed by the Oak Ridge National Laboratory. The smart repeater functions as a deployable communications platform that can be dynamically reconfigured to cross-link the radios of participating federal, state, and local government agencies. This interconnection capability improves the coordination and execution of multi-agency operations, including coordinated law enforcement activities and general emergency or disaster response scenarios. The repeater provides multiple channels of operation in the 30--50, 118--136, 138--174, and 403--512 MHz land mobile communications and aircraft bands while providing the ability to cross-connect among multiple frequencies, bands, modulation types, and encryption formats. Additionally, two telephone interconnects provide links to the fixed and cellular telephone networks. The 800- and 900-MHz bands are not supported by the prototype, but the modular design of the system accommodates future retrofits to extend frequency capabilities with minimal impact to the system. Configuration of the repeater is through a portable personal computer with a Windows-based graphical interface control screen that provides dynamic reconfiguration of network interconnections and formats.

  10. Transformation-associated recombination between diverged and homologous DNA repeats is induced by strand breaks

    SciTech Connect

    Larionov, V.; Kouprina, N. |; Eldarov, M. |; Perkins, E.; Porter, G.; Resnick, M.A.

    1994-10-01

    Rearrangement and deletion within plasmid DNA is commonly observed during transformation. We have examined the mechanisms of transformation-associated recombination in the yeast Saccharomyces cerevisiae using a plasmid system which allowed the effects of physical state and/or extent of homology on recombination to be studied. The plasmid contains homologous or diverged (19%) DNA repeats separated by a genetically detectable color marker. Recombination during transformation for covalently closed circular plasmids was over 100-fold more frequent than during mitotic-growth. The frequency of recombination is partly dependent on the method of transformation In that procedures involving lithium acetate or spheroplasting yield higher frequencies than electroporation. When present in the repeats, unique single-strand breaks that are ligatable, as well as double-strand breaks, lead to high levels of recombination between diverged and identical repeats. The transformation-associated recombination between repeat DNA`s is under the influence of the RAD52, RAD1 and the RNC1 genes.

  11. A repeater type biotelemetry system for use on wild big game animals.

    PubMed

    Cupal, J J; Ward, A L; Weeks, R W

    1975-01-01

    A repeater type telemetry system was developed and field tested on a wild elk near laramie, Wyoming, in the summer of 1973. The telemetry system consisted of the following: (a) a heat flow rate sensing implanted transmitter, (b) a repeater type neck collar and (c) a portable receiving station consisting of a receiver, decoding circuitry and analog chart recorder. The transmitter in (a) produced relatively low frequency rf pulses whose repetition rate was directly proportional to heat flow rate through the hide of the animal. In (b), the pulses from the implant are sensed and retransmitted using a relatively high power, high frequency transmitter. A second rf pulse was generated whose pulse spacing was related to animal activity. Details of circuit design and performance are given. Field experience has shown that this method is extremely useful for the monitoring of biological data from secretive big game animals such as elk.

  12. Repeatability of heart rate variability in congenital hypothyroidism as analysed by detrended fluctuation analysis.

    PubMed

    Echeverría, J C; Solís, L I; Pérez, J E; Gaitán, M J; Rivera, I R; Mandujano, M; Sánchez, M C; González-Camarena, R

    2009-10-01

    The analysis of heart rate fluctuations, or heart rate variability (HRV), may be applied to explore children's neurodevelopment. However, previous studies have reported poor reliability (repeatability) of HRV measures in children at rest and during light exercise. Whether the reliability can be improved by controlling variables such as physical activity, breathing rate and tidal volume, or by selecting non-conventional techniques for analysing the data remains as an open question. We evaluated the short-term repeatability of RR-interval data from medicated children with congenital hypothyroidism (CH). The alpha(1) exponents, obtained by detrended fluctuation analysis (DFA), from the data of 21 children collected at two different sessions were compared. Elapsed days between sessions were 59 +/- 33, and data were obtained during 10 min, trying to restrict the children's activity while being seated. We found statistical agreement between the means of alpha(1) exponents for each session (p = 0.94) and no bias with a low-coefficient variation (9.1%); an intraclass correlation coefficient ri = 0.48 ([0.14 0.72], 95% confidence interval) was also estimated. These findings, which were compared with results obtained by conventional time and frequency techniques, indicate the existence of agreement between the alpha(1) exponents obtained at each session, thereby providing support concerning the repeatability of HRV data as analysed by DFA in children with congenital hypothyroidism. Of particular interest was also the agreement found by using the central frequency of the high-frequency band and the parameter pNN20, both showing better or similar ri than alpha(1) (0.77 [0.57 0.89] and 0.51 [0.17 0.74], respectively), yet considerably better repeatability than other conventional time and frequency parameters.

  13. A dynamic system for single and repeated exposure of airway epithelial cells to gaseous pollutants.

    PubMed

    Kastner, Pierre Edouard; Le Calvé, Stéphane; Zheng, Wuyin; Casset, Anne; Pons, Françoise

    2013-03-01

    In vitro models are promising approaches to investigate the adverse effects and the mode of action of air pollutants on the respiratory tract. We designed a dynamic system that allows the single or repeated exposure of cultured cells to two major indoor air gaseous pollutants, formaldehyde (HCHO) and nitrogen dioxide (NO2), alone or as a mixture. In this system, the Calu-3 human bronchial epithelial cell line was exposed at the air-liquid interface (ALI) or submerged by culture medium to synthetic air or to target concentrations of HCHO and/or NO2 once or on 4 consecutive days before assessment of cell viability and necrosis, IL-6 and IL-8 release and trans-epithelial electrical resistance. Our data showed that whereas the ALI method can be used for single short-term exposures only, the submerged method provides the possibility to expose Calu-3 cells in a repeated manner. As well, we found that repeated exposures of the cells to HCHO and NO2 at concentrations that can be found indoors triggered a significant decrease in cell metabolism and an increase in IL-8 release that were not evoked by a single exposure. Thus, our work highlights the fact that the development of systems and methods that allow repeated exposures of cultured cells to gaseous compounds in mixtures is of major interest to evaluate the impact of air pollution on the respiratory tract.

  14. Insertion of a Telomere Repeat Sequence into a Mammalian Gene Causes Chromosome Instability

    PubMed Central

    Kilburn, April E.; Shea, Martin J.; Sargent, R. Geoffrey; Wilson, John H.

    2001-01-01

    Telomere repeat sequences cap the ends of eucaryotic chromosomes and help stabilize them. At interstitial sites, however, they may destabilize chromosomes, as suggested by cytogenetic studies in mammalian cells that correlate interstitial telomere sequence with sites of spontaneous and radiation-induced chromosome rearrangements. In no instance is the length, purity, or orientation of the telomere repeats at these potentially destabilizing interstitial sites known. To determine the effects of a defined interstitial telomere sequence on chromosome instability, as well as other aspects of DNA metabolism, we deposited 800 bp of the functional vertebrate telomere repeat, TTAGGG, in two orientations in the second intron of the adenosine phosphoribosyltransferase (APRT) gene in Chinese hamster ovary cells. In one orientation, the deposited telomere sequence did not interfere with expression of the APRT gene, whereas in the other it reduced mRNA levels slightly. The telomere sequence did not induce chromosome truncation and the seeding of a new telomere at a frequency above the limits of detection. Similarly, the telomere sequence did not alter the rate or distribution of homologous recombination events. The interstitial telomere repeat sequence in both orientations, however, dramatically increased gene rearrangements some 30-fold. Analysis of individual rearrangements confirmed the involvement of the telomere sequence. These studies define the telomere repeat sequence as a destabilizing element in the interior of chromosomes in mammalian cells. PMID:11113187

  15. [Data mining of simple sequence repeats in transcriptome sequences of Tibetan medicinal plant Zangyinchen Swertia mussotii].

    PubMed

    Liu, Yue; Yue Chun-Jiang; Wang, Yi; Ma, Jia-qiang; Sun, Hong-bo; Luo, Min; Ma, Peng-ju; Zhang, Lin-xia; Ma, Xu; Chen, Chuan-chuan; Li, Hua; Tang, Li

    2015-06-01

    MISA (MicroSAtelite) software was employed to screen SSRs in 68 787 contigs of Swertia mussotii transcriptome sequences. 5 610 SSRs were distributed in 5 099 contigs which accounted for 7.41% of 68 787 contigs. There are 220 kinds of SSR motifs existing in S. mussotii transcriptome. On average, SSRs occurred every 12.60 kb in length. In the SSRs, the tri-nucleotide repeat motif was the most abundant (45.99%), followed by the di-nucleotide (41.62%). AT/TA and AAT/TTA were the main types of motif in di-, tri-nucleotide repeats. The repeat numbers of SSRs which from S. mussotii transcriptome SSRs were mainly from 5 to 10 and motif length of them mostly ranged from 12 bp to 30 bp. A total of 30 651 contigs were annotated, and only 1 447 SSRs were occurred in protein-coding regions. In the six repeat motifs, tri-nucleotide repeats were the most abundant in coding regions (928). There are abundant SSRs in S. mussotii transcriptome with high frequency and various types, indicating their usefulness in theory. This research may lay the foundation for designing the targeted SSR primers and developing SSR molecular markers by mining the information of SSRs loci in S. mussotii transcriptome sequences data.

  16. Mining and survey of simple sequence repeats in expressed sequence tags of dicotyledonous species.

    PubMed

    Kumpatla, Siva P; Mukhopadhyay, Snehasis

    2005-12-01

    Simple sequence repeat (SSR) markers are widely used in many plant and animal genomes due to their abundance, hypervariability, and suitability for high-throughput analysis. Development of SSR markers using molecular methods is time consuming, laborious, and expensive. Use of computational approaches to mine ever-increasing sequences such as expressed sequence tags (ESTs) in public databases permits rapid and economical discovery of SSRs. Most of such efforts to date focused on mining SSRs from monocotyledonous ESTs. In this study, we have computationally mined and examined the abundance of SSRs in more than 1.54 million ESTs belonging to 55 dicotyledonous species. The frequency of ESTs containing SSRs among species ranged from 2.65% to 16.82%. Dinucleotide repeats were found to be the most abundant followed by tri- or mono-nucleotide repeats. The motifs A/T, AG/GA/CT/TC, and AAG/AGA/GAA/CTT/TTC/TCT were the predominant mono-, di-, and tri-nucleotide SSRs, respectively. Most of the mononucleotide SSRs contained 15-25 repeats, whereas the majority of the di- and tri-nucleotide SSRs contained 5-10 repeats. The comprehensive SSR survey data presented here demonstrates the potential of in silico mining of ESTs for rapid development of SSR markers for genetic analysis and applications in dicotyledonous crops.

  17. Repeated electrical stimulation of reward-related brain regions affects cocaine but not "natural" reinforcement.

    PubMed

    Levy, Dino; Shabat-Simon, Maytal; Shalev, Uri; Barnea-Ygael, Noam; Cooper, Ayelet; Zangen, Abraham

    2007-12-19

    Drug addiction is associated with long-lasting neuronal adaptations including alterations in dopamine and glutamate receptors in the brain reward system. Treatment strategies for cocaine addiction and especially the prevention of craving and relapse are limited, and their effectiveness is still questionable. We hypothesized that repeated stimulation of the brain reward system can induce localized neuronal adaptations that may either potentiate or reduce addictive behaviors. The present study was designed to test how repeated interference with the brain reward system using localized electrical stimulation of the medial forebrain bundle at the lateral hypothalamus (LH) or the prefrontal cortex (PFC) affects cocaine addiction-associated behaviors and some of the neuronal adaptations induced by repeated exposure to cocaine. Repeated high-frequency stimulation in either site influenced cocaine, but not sucrose reward-related behaviors. Stimulation of the LH reduced cue-induced seeking behavior, whereas stimulation of the PFC reduced both cocaine-seeking behavior and the motivation for its consumption. The behavioral findings were accompanied by glutamate receptor subtype alterations in the nucleus accumbens and the ventral tegmental area, both key structures of the reward system. It is therefore suggested that repeated electrical stimulation of the PFC can become a novel strategy for treating addiction. PMID:18094257

  18. Repeat film analysis and its implications for quality assurance in dental radiology: An institutional case study

    PubMed Central

    Acharya, Shruthi; Pai, Keerthilatha M.; Acharya, Shashidhar

    2015-01-01

    Context: The goal of any radiologist is to produce the highest quality diagnostic radiographs, while keeping patient exposure as low as reasonably achievable (ALARA). Aims: The aim of this study was to describe the reasons for radiograph rejections through a repeat film analysis in an Indian dental school. Settings and Design: An observational study conducted in the Department of Oral Medicine and Radiology, Manipal College of Dental Sciences, Manipal. Materials and Methods: During a 6-month study period, a total of 9,495 intra-oral radiographs and 2339 extraoral radiographs taken in the Radiology Department were subjected to repeat film analysis. Statistical Analysis Used: SPSS Version 16. Descriptive analysis used. Results: The results showed that the repeat rates were 7.1% and 5.86% for intraoral and extraoral radiographs, respectively. Among the causes for errors reported, positioning error (38.7%) was the most common, followed by improper angulations (26.1%), and improper film placement (11.2%) for intra-oral radiographs. The study found that the maximum frequency of repeats among extraoral radiographs was for panoramic radiographs (49%) followed by lateral cephalogram (33%), and paranasal sinus view (14%). It was also observed that repeat rate of intraoral radiographs was highest for internees (44.7%), and undergraduate students (28.2%). Conclusions: The study pointed to a need for more targeted interventions to achieve the goal of keeping patient exposure ALARA in a dental school setting. PMID:26321841

  19. Repeatability of a running heat tolerance test.

    PubMed

    Mee, Jessica A; Doust, Jo; Maxwell, Neil S

    2015-01-01

    At present there is no standardised heat tolerance test (HTT) procedure adopting a running mode of exercise. Current HTTs may misdiagnose a runner's susceptibility to a hyperthermic state due to differences in exercise intensity. The current study aimed to establish the repeatability of a practical running test to evaluate individual's ability to tolerate exercise heat stress. Sixteen (8M, 8F) participants performed the running HTT (RHTT) (30 min, 9 km h(-1), 2% elevation) on two separate occasions in a hot environment (40 °C and 40% relative humidity). There were no differences in peak rectal temperature (RHTT1: 38.82 ± 0.47 °C, RHTT2: 38.86 ± 0.49 °C, Intra-class correlation coefficient (ICC)=0.93, typical error of measure (TEM) = 0.13 °C), peak skin temperature (RHTT1: 38.12 ± 0.45, RHTT2: 38.11 ± 0.45 °C, ICC = 0.79, TEM = 0.30 °C), peak heart rate (RHTT1: 182 ± 15 beats min(-1), RHTT2: 183 ± 15 beats min(-1), ICC = 0.99, TEM = 2 beats min(-1)), nor sweat rate (1721 ± 675 g h(-1), 1716 ± 745 g h(-1), ICC = 0.95, TEM = 162 g h(-1)) between RHTT1 and RHTT2 (p>0.05). Results demonstrate good agreement, strong correlations and small differences between repeated trials, and the TEM values suggest low within-participant variability. The RHTT was effective in differentiating between individuals physiological responses; supporting a heat tolerance continuum. The findings suggest the RHTT is a repeatable measure of physiological strain in the heat and may be used to assess the effectiveness of acute and chronic heat alleviating procedures. PMID:25774031

  20. Imprints of superfluidity on magnetoelastic quasiperiodic oscillations of soft gamma-ray repeaters.

    PubMed

    Gabler, Michael; Cerdá-Durán, Pablo; Stergioulas, Nikolaos; Font, José A; Müller, Ewald

    2013-11-22

    Our numerical simulations show that axisymmetric, torsional, magnetoelastic oscillations of magnetars with a superfluid core can explain the whole range of observed quasiperiodic oscillations (QPOs) in the giant flares of soft gamma-ray repeaters. There exist constant phase QPOs at f is < or approximately equal to 150 Hz and resonantly excited high-frequency QPOs (f>500 Hz), in good agreement with observations. The range of magnetic field strengths required to match the observed QPO frequencies agrees with that from spin-down estimates. These results suggest that there is at least one superfluid species in magnetar cores.

  1. Repeated vitrification/warming of human sperm gives better results than repeated slow programmable freezing

    PubMed Central

    Vutyavanich, Teraporn; Lattiwongsakorn, Worashorn; Piromlertamorn, Waraporn; Samchimchom, Sudarat

    2012-01-01

    In this study, we compared the effects of repeated freezing/thawing of human sperm by our in-house method of rapid freezing with slow programmable freezing. Sperm samples from 11 normozoospermic subjects were processed through density gradients and divided into three aliquots: non-frozen, rapid freezing and slow programmable freezing. Sperm in the rapid freezing group had better motility and viability than those in the slow freezing group (P<0.01) after the first, second and third cycles of freezing/thawing, but there was no difference in morphology. In the second experiment, rapid freezing was repeated three times in 20 subjects. The samples from each thawing cycle were evaluated for DNA fragmentation using the alkaline comet assay. DNA fragmentation began to increase considerably after the second cycle of freezing/thawing, but to a level that was not clinically important. In the third experiment, rapid freezing was done repeatedly in 10 subjects, until no motile sperm were observed after thawing. The median number of repeated freezing/thawing that yielded no motile sperm was seven (range: 5–8, mean: 6.8). In conclusion, we demonstrated that repeated freezing/thawing of processed semen using our rapid freezing method gave better results than standard slow programmable freezing. This method can help maximize the usage of precious cryopreserved sperm samples in assisted reproduction technology. PMID:23064685

  2. Capping motifs stabilize the leucine-rich repeat protein PP32 and rigidify adjacent repeats.

    PubMed

    Dao, Thuy P; Majumdar, Ananya; Barrick, Doug

    2014-06-01

    Capping motifs are found to flank most β-strand-containing repeat proteins. To better understand the roles of these capping motifs in organizing structure and stability, we carried out folding and solution NMR studies on the leucine-rich repeat (LRR) domain of PP32, which is composed of five tandem LRR, capped by α-helical and β-hairpin motifs on the N- and C-termini. We were able to purify PP32 constructs lacking either cap and containing destabilizing substitutions. Removing the C-cap results in complete unfolding of PP32. Removing the N-cap has a much less severe effect, decreasing stability but retaining much of its secondary structure. In contrast, the dynamics and tertiary structure of the first two repeats are significantly perturbed, based on (1)H-(15)N relaxation studies, chemical shift perturbations, and residual dipolar couplings. However, more distal repeats (3 to C-cap) retain their native tertiary structure. In this regard, the N-cap drives the folding of adjacent repeats from what appears to be a molten-globule-like state. This interpretation is supported by extensive analysis using core packing substitutions in the full-length and N-cap-truncated PP32. This work highlights the importance of caps to the stability and structural integrity of β-strand-containing LRR proteins, and emphasizes the different contributions of the N- and C-terminal caps. PMID:24659532

  3. Distillation by repeated measurements: Continuous spectrum case

    SciTech Connect

    Bellomo, Bruno; Compagno, Giuseppe; Nakazato, Hiromichi; Yuasa, Kazuya

    2010-12-15

    Repeated measurements on one part of a bipartite system strongly affect the other part that is not measured, the dynamics of which is regulated by an effective contracted evolution operator. When the spectrum of this operator is discrete, the nonmeasured system is driven into a pure state, irrespective of the initial state, provided that the spectrum satisfies certain conditions. We show here that, even in the case of continuous spectrum, an effective distillation can occur under rather general conditions. We confirm it by applying our formalism to a simple model.

  4. Innovative collaboration to prevent repeated adolescent pregnancies.

    PubMed

    Saunders, R B; Brown, H N

    1997-01-01

    Nurse educators from a university setting and staff from the county health department collaborated to establish an innovative program to prevent repeated pregnancy in adolescents. Called Dollar-A-Day and patterned after the original in Denver, CO, the program was operated jointly for 5 years and today continues to operate under the auspices of the health department. Success of the venture is attributed to use of skills in assessment, building, managing, and evaluating, as described by Loxley (1997). These elements were used to construct a context for collaboration.

  5. Multifunctional protein: cardiac ankyrin repeat protein*

    PubMed Central

    Zhang, Na; Xie, Xiao-jie; Wang, Jian-an

    2016-01-01

    Cardiac ankyrin repeat protein (CARP) not only serves as an important component of muscle sarcomere in the cytoplasm, but also acts as a transcription co-factor in the nucleus. Previous studies have demonstrated that CARP is up-regulated in some cardiovascular disorders and muscle diseases; however, its role in these diseases remains controversial now. In this review, we will discuss the continued progress in the research related to CARP, including its discovery, structure, and the role it plays in cardiac development and heart diseases. PMID:27143260

  6. Yet another model of soft gamma repeaters

    NASA Technical Reports Server (NTRS)

    Katz, J. I.; Toole, H. A.; Unruh, S. H.

    1994-01-01

    We develop a model of soft gamma repeaters (SGRs) in which a supernova leaves planets orbiting a neutron star in intersecting orbits. These planets will collide in approximately 10(exp 4) yr if their orbits are coplanar. Some fragments of debris lose their angular momentum in the collision and fall onto the neutron star, producing a SGR. The initial accretion of matter left by the collision with essntially no angular momentum may produce a superburst like that of 1979 March 5, while debris fragments which later lose their angular momentum produce an irregular but non-Poissonian pattern of smaller bursts resembling those observed in spectrum and duration.

  7. Synthesis of biotinylated keratan sulfate repeating disaccharides.

    PubMed

    Takeda, Naoko; Tamura, Jun-Ichi

    2014-01-01

    We synthesized four types of keratan and keratan sulfate repeating disaccharides containing non-sulfate, Galβ1-4GlcNAcβ, and three types of sulfates, Gal6Sβ1-4GlcNAcβ, Galβ1-4GlcNAc6Sβ, and Gal6Sβ1-4GlcNAc6Sβ in an efficient and stereo-controlled manner. These disaccharides were conjugated with biotin via a hydrophilic linker at the reducing terminal.

  8. Platelet peripheral benzodiazepine receptors in repeated stress

    SciTech Connect

    Dar, D.E.; Bidder, M.; Gavish, M. ); Weizman, A.; Karp, L.; Tyano, S. ); Grinshpoon, A.; Bleich, A.

    1991-01-01

    ({sup 3}H)PK 11195 binding to platelet membranes and plasma stress hormones were studied in soldiers at the beginning of a parachute training course, following 6 days of preparatory exercises, and after the fourth actual parachute jump. A slight reduction (15%; NS) in the number of peripheral benzodiazepine receptors (PBR) was detected at the end of the exercise period, prior to the first jump. Reduced density of PBR was observed immediately after the repeated actual jumps. Equilibrium dissociation constants were not affected by the stressful situation. Plasma cortisol and prolactin levels remained unaltered during the entire study period.

  9. On the nature of soft gamma repeaters

    NASA Technical Reports Server (NTRS)

    Norris, J. P.; Hertz, P.; Wood, K. S.; Kouveliotou, C.

    1991-01-01

    The nature of soft gamma repeaters (SGRs) is discussed on the basis of data available for the March 5, 1979 superburst described by Cline et al. (1982) and for the less intense bursts detected by instruments on board Venera 11/12 and 13/14. It is argued that the three known SGR bursters can be explained most economically and consistently as belonging to a single class, with source distances of tens of kiloparsecs. The viability of several proposed models developed for the SGR energy release mechanism is examined.

  10. Sintered composite medium and filter

    DOEpatents

    Bergman, Werner

    1987-01-01

    A particulate filter medium is formed of a sintered composite of 0.5 micron diameter quartz fibers and 2 micron diameter stainless steel fibers. A preferred composition is about 40 vol. % quartz and about 60 vol. % stainless steel fibers. The media is sintered at about 1100.degree. C. to bond the stainless steel fibers into a cage network which holds the quartz fibers. High filter efficiency and low flow resistance are provided by the smaller quartz fibers. High strength is provided by the stainless steel fibers. The resulting media has a high efficiency and low pressure drop similar to the standard HEPA media, with tensile strength at least four times greater, and a maximum operating temperature of about 550.degree. C. The invention also includes methods to form the composite media and a HEPA filter utilizing the composite media. The filter media can be used to filter particles in both liquids and gases.

  11. Medium consumption in holographic memories.

    PubMed

    Ayres, Mark R; McLeod, Robert R

    2009-07-01

    The dynamic range of holographic storage media is traditionally characterized in terms of M/#. However, this is a system parameter that assumes simple, uniform plane-wave holograms. Realistic architectures violate this assumption so that M/# measured with plane waves cannot be used to predict system diffraction efficiency. Thus, there currently is no systematic method predicting signal strength and medium consumption for holographic storage architectures a priori. We define a new material parameter, the modulation integral, M(I), and show how this may be used for dynamic range budgeting and diffraction efficiency prediction in complex storage systems. The method is illustrated by applying it to two architectures, collinear and angle polytopic, in order to estimate the M/# required for achieving a target storage density in the presence of empirical optical scatter noise.

  12. Theory of interstellar medium diagnostics

    NASA Technical Reports Server (NTRS)

    Fahr, H. J.

    1983-01-01

    The theoretical interpretation of observed interplanetary resonance luminescence patterns is used as one of the must promising methods to determine the state of the local interstellar medium (LISM). However, these methods lead to discrepant results that would be hard to understand in the framework of any physical LISM scenario. Assuming that the observational data are reliable, two possibilities which could help to resolve these discrepancies are discussed: (1) the current modeling of resonance luminescence patterns is unsatisfactory and has to be improved, and (2) the extrapolated interstellar parameters are not indicative of the unperturbed LISM state, but rather designate an intermediate state attained in the outer regions of the solar system. It is shown that a quantitative treatment of the neutral gas-plasma interaction effects in the interface between the heliospheric and the interstellar plasmas is of major importance for the correct understanding of the whole complex.

  13. Shallow repeating seismic events under an alpine glacier at Mount Rainier, Washington, USA

    USGS Publications Warehouse

    Thelen, Weston A.; Allstadt, Kate; De Angelis, Silvio; Malone, Stephen D.; Moran, Seth C.; Vidale, John

    2013-01-01

    We observed several swarms of repeating low-frequency (1–5 Hz) seismic events during a 3 week period in May–June 2010, near the summit of Mount Rainier, Washington, USA, that likely were a result of stick–slip motion at the base of alpine glaciers. The dominant set of repeating events ('multiplets') featured >4000 individual events and did not exhibit daytime variations in recurrence interval or amplitude. Volcanoes and glaciers around the world are known to produce seismic signals with great variability in both frequency content and size. The low-frequency character and periodic recurrence of the Mount Rainier multiplets mimic long-period seismicity often seen at volcanoes, particularly during periods of unrest. However, their near-surface location, lack of common spectral peaks across the recording network, rapid attenuation of amplitudes with distance, and temporal correlation with weather systems all indicate that ice-related source mechanisms are the most likely explanation. We interpret the low-frequency character of these multiplets to be the result of trapping of seismic energy under glacial ice as it propagates through the highly heterogeneous and attenuating volcanic material. The Mount Rainier multiplet sequences underscore the difficulties in differentiating low-frequency signals due to glacial processes from those caused by volcanic processes on glacier-clad volcanoes.

  14. Cliff Collapse Hazard from Repeated Multicopter Uav Acquisitions: Return on Experience

    NASA Astrophysics Data System (ADS)

    Dewez, T. J. B.; Leroux, J.; Morelli, S.

    2016-06-01

    Cliff collapse poses a serious hazard to infrastructure and passers-by. Obtaining information such as magnitude-frequency relationship for a specific site is of great help to adapt appropriate mitigation measures. While it is possible to monitor hundreds-of-meter-long cliff sites with ground based techniques (e.g. lidar or photogrammetry), it is both time consuming and scientifically limiting to focus on short cliff sections. In the project SUAVE, we sought to investigate whether an octocopter UAV photogrammetric survey would perform sufficiently well in order to repeatedly survey cliff face geometry and derive rock fall inventories amenable to probabilistic rock fall hazard computation. An experiment was therefore run on a well-studied site of the chalk coast of Normandy, in Mesnil Val, along the English Channel (Northern France). Two campaigns were organized in January and June 2015 which surveyed about 60 ha of coastline, including the 80-m-high cliff face, the chalk platform at its foot, and the hinterland in a matter of 4 hours from start to finish. To conform with UAV regulations, the flight was flown in 3 legs for a total of about 30 minutes in the air. A total of 868 and 1106 photos were respectively shot with a Sony NEX 7 with fixed focal 16mm. Three lines of sight were combined: horizontal shots for cliff face imaging, 45°-oblique views to tie plateau/platform photos with cliff face images, and regular vertical shots. Photogrammetrically derived dense point clouds were produced with Agisoft Photoscan at ultra-high density (median density is 1 point every 1.7cm). Point cloud density proved a critical parameter to reproduce faithfully the chalk face's geometry. Tuning down the density parameter to "high" or "medium", though efficient from a computational point of view, generated artefacts along chalk bed edges (i.e. smoothing the sharp gradient) and ultimately creating ghost volumes when computing cloud to cloud differences. Yet, from a hazard point of

  15. Large-scale convective instability in an electroconducting medium with small-scale helicity

    SciTech Connect

    Kopp, M. I.; Tur, A. V.; Yanovsky, V. V.

    2015-04-15

    A large-scale instability occurring in a stratified conducting medium with small-scale helicity of the velocity field and magnetic fields is detected using an asymptotic many-scale method. Such a helicity is sustained by small external sources for small Reynolds numbers. Two regimes of instability with zero and nonzero frequencies are detected. The criteria for the occurrence of large-scale instability in such a medium are formulated.

  16. Sequence analysis of Vicia faba repeated DNA, the FokI repeat element.

    PubMed Central

    Kato, A; Yakura, K; Tanifuji, S

    1984-01-01

    A type of highly repeated DNA sequences present in the genome of Vicia faba was detected by digestion its nuclear DNA with FokI endonuclease and fractionating the digests on polyacrylamide gels. Four fragments of 59, 108, 177 and 246 bp of the FokI repeated sequences were collected from the gels and their primary structures were determined by the method of Maxam and Gilbert. These repeated DNA sequences were shown to be a multiple tandem array of a 59 bp sequence element. And its nucleotide sequence was almost completely conserved among all the sequence members of each the size class and also among these classes. This sequence element consists of a duplet of an about the duplet has an incomplete dyad symmetrical structure. Images PMID:6089113

  17. Self-similar pulse-shape mode for femtosecond pulse propagation in medium with resonant nonlinearity

    NASA Astrophysics Data System (ADS)

    Trofimov, Vyacheslav A.; Zakharova, Irina G.; Konar, Swapan

    2014-05-01

    We investigate the mode of laser pulse propagation in homogeneous medium with resonant nonlinearity, at which the shape of pulse is self-similar one along some distance of propagation. We take into account a laser pulse frequency detuning from resonant frequency. Both types of sign for frequency detuning are considered. This results in appearance of a refractive index grating which induced self-action of a laser pulse. I certain cases we develop analytical solution of corresponding nonlinear eigenfunction problem of laser pulse propagation in medium for multi-photon resonance. This solution is confirmed by computer simulation of an eigenfunction problem for Schrödinger equation with considered nonlinearity. Using computer simulation, one shows a validity of existence of such kind of laser pulse propagation in a medium with resonant nonlinear response.

  18. Medium-Based Design: Extending a Medium to Create an Exploratory Learning Environment

    ERIC Educational Resources Information Center

    Rick, Jochen; Lamberty, K. K.

    2005-01-01

    This article introduces "medium-based" design -- an approach to creating "exploratory learning environments" using the method of "extending a medium". First, the characteristics of exploratory learning environments and medium-based design are described and grounded in related work. Particular attention is given to "extending a medium" --…

  19. Chromosome-specific DNA Repeat Probes

    SciTech Connect

    Baumgartner, Adolf; Weier, Jingly Fung; Weier, Heinz-Ulrich G.

    2006-03-16

    In research as well as in clinical applications, fluorescence in situ hybridization (FISH) has gained increasing popularity as a highly sensitive technique to study cytogenetic changes. Today, hundreds of commercially available DNA probes serve the basic needs of the biomedical research community. Widespread applications, however, are often limited by the lack of appropriately labeled, specific nucleic acid probes. We describe two approaches for an expeditious preparation of chromosome-specific DNAs and the subsequent probe labeling with reporter molecules of choice. The described techniques allow the preparation of highly specific DNA repeat probes suitable for enumeration of chromosomes in interphase cell nuclei or tissue sections. In addition, there is no need for chromosome enrichment by flow cytometry and sorting or molecular cloning. Our PCR-based method uses either bacterial artificial chromosomes or human genomic DNA as templates with {alpha}-satellite-specific primers. Here we demonstrate the production of fluorochrome-labeled DNA repeat probes specific for human chromosomes 17 and 18 in just a few days without the need for highly specialized equipment and without the limitation to only a few fluorochrome labels.

  20. Nanostructured functional films from engineered repeat proteins

    PubMed Central

    Grove, Tijana Z.; Regan, Lynne; Cortajarena, Aitziber L.

    2013-01-01

    Fundamental advances in biotechnology, medicine, environment, electronics and energy require methods for precise control of spatial organization at the nanoscale. Assemblies that rely on highly specific biomolecular interactions are an attractive approach to form materials that display novel and useful properties. Here, we report on assembly of films from the designed, rod-shaped, superhelical, consensus tetratricopeptide repeat protein (CTPR). We have designed three peptide-binding sites into the 18 repeat CTPR to allow for further specific and non-covalent functionalization of films through binding of fluorescein labelled peptides. The fluorescence signal from the peptide ligand bound to the protein in the solid film is anisotropic, demonstrating that CTPR films can impose order on otherwise isotropic moieties. Circular dichroism measurements show that the individual protein molecules retain their secondary structure in the film, and X-ray scattering, birefringence and atomic force microscopy experiments confirm macroscopic alignment of CTPR molecules within the film. This work opens the door to the generation of innovative biomaterials with tailored structure and function. PMID:23594813

  1. Airborne Radar Interferometric Repeat-Pass Processing

    NASA Technical Reports Server (NTRS)

    Hensley, Scott; Michel, Thierry R.; Jones, Cathleen E.; Muellerschoen, Ronald J.; Chapman, Bruce D.; Fore, Alexander; Simard, Marc; Zebker, Howard A.

    2011-01-01

    Earth science research often requires crustal deformation measurements at a variety of time scales, from seconds to decades. Although satellites have been used for repeat-track interferometric (RTI) synthetic-aperture-radar (SAR) mapping for close to 20 years, RTI is much more difficult to implement from an airborne platform owing to the irregular trajectory of the aircraft compared with microwave imaging radar wavelengths. Two basic requirements for robust airborne repeat-pass radar interferometry include the ability to fly the platform to a desired trajectory within a narrow tube and the ability to have the radar beam pointed in a desired direction to a fraction of a beam width. Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) is equipped with a precision auto pilot developed by NASA Dryden that allows the platform, a Gulfstream III, to nominally fly within a 5 m diameter tube and with an electronically scanned antenna to position the radar beam to a fraction of a beam width based on INU (inertial navigation unit) attitude angle measurements.

  2. Compression of strings with approximate repeats.

    PubMed

    Allison, L; Edgoose, T; Dix, T I

    1998-01-01

    We describe a model for strings of characters that is loosely based on the Lempel Ziv model with the addition that a repeated substring can be an approximate match to the original substring; this is close to the situation of DNA, for example. Typically there are many explanations for a given string under the model, some optimal and many suboptimal. Rather than commit to one optimal explanation, we sum the probabilities over all explanations under the model because this gives the probability of the data under the model. The model has a small number of parameters and these can be estimated from the given string by an expectation-maximization (EM) algorithm. Each iteration of the EM algorithm takes O(n2) time and a few iterations are typically sufficient. O(n2) complexity is impractical for strings of more than a few tens of thousands of characters and a faster approximation algorithm is also given. The model is further extended to include approximate reverse complementary repeats when analyzing DNA strings. Tests include the recovery of parameter estimates from known sources and applications to real DNA strings.

  3. Ultrasonic flowmeters undergo accuracy, repeatability tests

    SciTech Connect

    Grimley, T.A.

    1996-12-23

    Two commercially available multipath ultrasonic flowmeters have undergone tests at Gas Research Institute`s metering research facility (MRF) at Southwest Research institute in San Antonio. The tests were conducted in baseline and disturbed-flow installations to assess baseline accuracy and repeatability over a range of flowrates and pressures. Results show the test meters are capable of accuracies within a 1% tolerance and with repeatability of better than 0.25% when the flowrate is greater than about 5% of capacity. The data also indicates that pressure may have an effect on meter error. Results further suggest that both the magnitude and character of errors introduced by flow disturbances are a function of meter design. Shifts of up to 0.6% were measured for meters installed 10D from a tee (1D = 1 pipe diameter). Better characterization of the effects of flow disturbances on measurement accuracy is needed to define more accurately the upstream piping requirements necessary to achieve meter performance within a specified tolerance. The paper discusses reduced station costs, test methods, baseline tests, effect of pressure, speed of sound, and disturbance tests.

  4. Distribution of repeat unit differences between alleles at tandem repeat microsatellite loci

    SciTech Connect

    Jin, L. |; Zhong, Y.; Chakraborty, R.

    1994-09-01

    PCR-based assays of tandemly repeated microsatellite loci detect genetic variation from which alleles may be scored by their repeat unit lengths. Comparison of allele sizes from such data yields a probability distribution (P{sub k}) of repeat unit differences (k) between alleles segregating in a population. We show that this distribution (P{sub k}; k = 0, 1,2,...) provides insight regarding the mechanism of production of new alleles at such loci and the demographic history of populations, far better than that obtained from other summary measures (e.g., heterozygosity, number of alleles, and the range of allele sizes). The distributions of P{sub k} under multi-step stepwise models of mutation are analytically derived, which show that when a population is at equilibrium under the mutation-drift balance, the distribution of repeat unit differences between alleles is positively skewed with a mode larger than zero. However, when the heterozygosity at a locus is low (say, less than 40%), P{sub k} is a monotonically decreasing function of k. Applications of this theory to data on repeat unit sizes at over 1,240 microsatellite loci from the Caucasians, categorized by the average heterozygosity of loci, indicate that at most microsatellite loci new alleles are produced by stepwise mutations, and this is consistent with the replication slippage mechanism of mutations. The repeat size changes of mutants are probably within one or two units of alleles from which the mutants arise. Distributions of P{sub k} at microsatellite loci located within genes show evidence of allele size constraints. No significant evidence of recent expansion of population sizes in the Caucasians is detected by the distribution of P{sub k}.

  5. Oscillatory motion of a viscous fluid in a porous medium

    SciTech Connect

    Siraev, R. R.

    2015-08-15

    An oscillatory flow of an incompressible fluid in a saturated porous medium in the presence of a solid inclusion has been theoretically studied. Unsteady filtration has been described by the Brinkman–Forchheimer equation, where inertial effects and terms with acceleration characteristic of high filtration rates and the presence of pulsations are taken into account. The convective part of the acceleration is responsible for nonlinear effects near macroinhomogeneities. These effects can play a noticeable role in unsteady flows in the porous medium, as is shown for the problem of a solid ball streamed by an oscillatory flow having a given velocity at infinity. The results indicate that a secondary averaged flow appears in the case of high frequencies and cannot be described by Darcy’s or Forchheimer’s filtration laws.

  6. New insights into the genetic instability in CCTG repeats.

    PubMed

    Guo, Pei; Lam, Sik Lok

    2015-10-01

    Tetranucleotide CCTG repeat expansion is associated with myotonic dystrophy type 2, which is an inherited and progressive muscle degeneration disease. Yet, no cure is available and the molecular mechanism of repeat expansion remains elusive. In this study, we used high-resolution nuclear magnetic resonance spectroscopy to reveal a mini-dumbbell structure formed by two CCTG repeats. Upon slippage in the nascent strand during DNA replication, the formation of the mini-dumbbell provides a possible pathway for a two-repeat expansion. In addition, fast exchange between two competing mini-dumbbells among three repeats results in a mini-loop structure that accounts for one-repeat expansion. These mini-dumbbell and mini-loop intermediates can also co-exist at multiple sites in CCTG repeats, leading to three or larger size repeat expansions. PMID:26384951

  7. 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.

  8. Spin-exchange frequency shift in alkali-metal-vapor cell frequency standards

    SciTech Connect

    Micalizio, Salvatore; Godone, Aldo; Levi, Filippo; Vanier, Jacques

    2006-03-15

    In this paper we calculate the effect of spin-exchange collisions in alkali-metal vapors. In the framework of the high-energy approximation, we evaluate the spin-exchange cross sections related to the line broadening and to the frequency shift of the ground state hyperfine transition. We do the calculation for the four isotopes, {sup 23}Na, {sup 39}K, {sup 87}Rb, and {sup 133}Cs. The results are used in particular to evaluate the spin-exchange frequency shift in Rb vapor cell frequency standards used in many applications. It turns out that, due to possible fluctuations in the atomic density, spin exchange may affect significantly the medium and long term frequency stability of the frequency standard.

  9. Elicitation of silymarin in cell cultures of Silybum marianum: effect of subculture and repeated addition of methyl jasmonate.

    PubMed

    Sánchez-Sampedro, Maria Angeles; Fernández-Tárrago, Jorge; Corchete, Purificación

    2009-10-01

    Production of silymarin and the effect of the elicitor, methyl jasmonate (MeJA), was monitored in cell cultures of Silybum marianum over 4 years. Silymarin concentrations gradually declined after prolonged subculture, making the success of elicitor strategy limited in long-term cultures. The continuous presence of MeJA in cultures for an extended period was necessary for induction of silymarin accumulation. A repeated elicitor strategy was not a good option for improving silymarin productivity in batch cultures. Removal of medium from elicited cultures and addition of fresh medium avoided the toxic effects of elicitor accumulation, allowing the system to respond to a repeated MeJA treatment without loss of productivity.

  10. Analysis of operational requirements for medium density air transportation. Volume 1: Summary

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The medium density air travel market was studied to determine the aircraft design and operational requirements. The impact of operational characteristics on the air travel system and the economic viability of the study aircraft were also evaluated. Medium density is defined in terms of numbers of people transported (20 to 500 passengers per day on round trip routes), and frequency of service ( a minumium of two and maximum of eight round trips per day) for 10 regional carriers. The operational characteristics of aircraft best suited to serve the medium density air transportation market are determined and a basepoint aircraft is designed from which tradeoff studies and parametric variations could be conducted. The impact of selected aircraft on the medium density market, economics, and operations is ascertained. Research and technology objectives for future programs in medium density air transportation are identified and ranked.

  11. Localization of a small change in a multiple scattering environment without modeling of the actual medium.

    PubMed

    Rakotonarivo, S T; Walker, S C; Kuperman, W A; Roux, P

    2011-12-01

    A method to actively localize a small perturbation in a multiple scattering medium using a collection of remote acoustic sensors is presented. The approach requires only minimal modeling and no knowledge of the scatterer distribution and properties of the scattering medium and the perturbation. The medium is ensonified before and after a perturbation is introduced. The coherent difference between the measured signals then reveals all field components that have interacted with the perturbation. A simple single scatter filter (that ignores the presence of the medium scatterers) is matched to the earliest change of the coherent difference to localize the perturbation. Using a multi-source/receiver laboratory setup in air, the technique has been successfully tested with experimental data at frequencies varying from 30 to 60 kHz (wavelength ranging from 0.5 to 1 cm) for cm-scale scatterers in a scattering medium with a size two to five times bigger than its transport mean free path.

  12. Fresnel drag of light by a moving nonlinear and nanostructured dielectric medium

    SciTech Connect

    Peiponen, Kai-Erik; Gornov, Evgeny

    2007-12-15

    The Fresnel drag is viewed in the frame of nonlinear and/or nanostructured uniformly moving media. It is shown that in the case of intense light pulse interaction with an optically nonlinear medium the relativistic frequency chirp due to self-phase modulation is smaller than in the rest frame. In the case of light interaction with optically linear or nonlinear nanostructured medium the Fresnel drag depends on the effective refractive index of the medium. While the nanostructures are in a liquid matrix the drag can be controlled by the fill fraction of the inclusions. As an example the Fresnel drag for optically linear Bruggeman liquid is considered.

  13. The propagation of a nonlinear sound wave in an unconsolidated granular medium

    NASA Astrophysics Data System (ADS)

    Naugolnykh, K. A.; Esipov, I. B.

    2005-11-01

    The propagation of a high-intensity sound wave in an unconsolidated medium is considered. Dissipation effects are taken into account on the basis of Buckingham’s theory of a relaxation mechanism of sound attenuation in a saturated sediment. The nonlinear evolution equation for the relaxing medium is obtained, and the solutions of this equation are analyzed. The second-harmonic generation in such a medium decays, as does the linear sound wave of the same frequency. The stationary weak shock profile has a specific form due to relaxation effects.

  14. Erroneous Memories Arising from Repeated Attempts to Remember

    ERIC Educational Resources Information Center

    Henkel, Linda A.

    2004-01-01

    The impact of repeated and prolonged attempts at remembering on false memory rates was assessed in three experiments. Participants saw and imagined pictures and then made repeated recall attempts before taking a source memory test. Although the number of items recalled increased with repeated tests, the net gains were associated with more source…

  15. 47 CFR 90.247 - Mobile repeater stations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Mobile repeater stations. 90.247 Section 90.247... MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.247 Mobile repeater stations. A... repeater to extend the communications range of hand-carried units subject to the following: (a)...

  16. Examining the Role of Lexical Frequency in the Acquisition and Processing of Sentential Complements

    ERIC Educational Resources Information Center

    Kidd, Evan; Lieven, Elena; Tomasello, Michael

    2006-01-01

    We present empirical data showing that the relative frequency with which a verb normally appears in a syntactic construction predicts young children's ability to remember and repeat sentences instantiating that construction. Children aged 2;10-5;8 years were asked to repeat grammatical and ungrammatical sentential complement sentences (e.g., "I…

  17. Are intertidal soft sediment assemblages affected by repeated oil spill events? A field-based experimental approach.

    PubMed

    Sandrini-Neto, Leonardo; Martins, César C; Lana, Paulo C

    2016-06-01

    This study investigates the impact of repeated diesel spills on the structure of intertidal macrofaunal assemblages of a subtropical estuary. Three frequencies of exposure events were compared against two dosages of oil in a factorial experiment with asymmetrical controls. Hypotheses were tested to distinguish between (i) the overall effect of oil spills, (ii) the effect of diesel dosage via different exposure regimes, and (iii) the effect of time since last spill. Repeated oil spills dramatically altered the overall structure of assemblages and reduced the total density of macrofauna and densities of dominant taxa. Increasing the frequency of oil spills negatively affected macrofauna. In general, frequent low-dosage oil spills were more deleterious than infrequent high-dosage ones. However, increases in densities of some taxa, mainly the gastropod Heleobia australis, were observed in response to infrequent spills. Our results highlight the importance of repeated exposure events in determining the extent of oil impacts.

  18. Are intertidal soft sediment assemblages affected by repeated oil spill events? A field-based experimental approach.

    PubMed

    Sandrini-Neto, Leonardo; Martins, César C; Lana, Paulo C

    2016-06-01

    This study investigates the impact of repeated diesel spills on the structure of intertidal macrofaunal assemblages of a subtropical estuary. Three frequencies of exposure events were compared against two dosages of oil in a factorial experiment with asymmetrical controls. Hypotheses were tested to distinguish between (i) the overall effect of oil spills, (ii) the effect of diesel dosage via different exposure regimes, and (iii) the effect of time since last spill. Repeated oil spills dramatically altered the overall structure of assemblages and reduced the total density of macrofauna and densities of dominant taxa. Increasing the frequency of oil spills negatively affected macrofauna. In general, frequent low-dosage oil spills were more deleterious than infrequent high-dosage ones. However, increases in densities of some taxa, mainly the gastropod Heleobia australis, were observed in response to infrequent spills. Our results highlight the importance of repeated exposure events in determining the extent of oil impacts. PMID:26890483

  19. AUTOMATIC FREQUENCY CONTROL SYSTEM

    DOEpatents

    Hansen, C.F.; Salisbury, J.D.

    1961-01-10

    A control is described for automatically matching the frequency 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 frequency determining element. A low frequency is mixed with the output of the driving oscillator and the resultant lower and upper sidebands are separately derived. The frequencies of the sidebands are compared with the secondary oscillator frequency. deriving a servo control signal to adjust a tuning element in the cavity and matching the cavity frequency to that of the driving oscillator. The driving oscillator may then be connected to the cavity.

  20. Automatic detection of regularly repeating vocalizations

    NASA Astrophysics Data System (ADS)

    Mellinger, David

    2005-09-01

    Many animal species produce repetitive sounds at regular intervals. This regularity can be used for automatic recognition of the sounds, providing improved detection at a given signal-to-noise ratio. Here, the detection of sperm whale sounds is examined. Sperm whales produce highly repetitive ``regular clicks'' at periods of about 0.2-2 s, and faster click trains in certain behavioral contexts. The following detection procedure was tested: a spectrogram was computed; values within a certain frequency band were summed; time windowing was applied; each windowed segment was autocorrelated; and the maximum of the autocorrelation within a certain periodicity range was chosen. This procedure was tested on sets of recordings containing sperm whale sounds and interfering sounds, both low-frequency recordings from autonomous hydrophones and high-frequency ones from towed hydrophone arrays. An optimization procedure iteratively varies detection parameters (spectrogram frame length and frequency range, window length, periodicity range, etc.). Performance of various sets of parameters was measured by setting a standard level of allowable missed calls, and the resulting optimium parameters are described. Performance is also compared to that of a neural network trained using the data sets. The method is also demonstrated for sounds of blue whales, minke whales, and seismic airguns. [Funding from ONR.

  1. 47 CFR 97.205 - Repeater station.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... km (10 miles) of the Arecibo Observatory or before changing the transmitting frequency, transmitter... notification thereof to the Interference Office, Arecibo Observatory, HC3 Box 53995, Arecibo, Puerto Rico 00612... the proposed operation is received by the FCC from the Arecibo Observatory, Arecibo, Puerto...

  2. 47 CFR 97.205 - Repeater station.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... km (10 miles) of the Arecibo Observatory or before changing the transmitting frequency, transmitter... notification thereof to the Interference Office, Arecibo Observatory, HC3 Box 53995, Arecibo, Puerto Rico 00612... the proposed operation is received by the FCC from the Arecibo Observatory, Arecibo, Puerto...

  3. 47 CFR 97.205 - Repeater station.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... km (10 miles) of the Arecibo Observatory or before changing the transmitting frequency, transmitter... notification thereof to the Interference Office, Arecibo Observatory, HC3 Box 53995, Arecibo, Puerto Rico 00612... the proposed operation is received by the FCC from the Arecibo Observatory, Arecibo, Puerto...

  4. Next generation sequencing (NGS) database for tandem repeats with multiple pattern 2°-shaft multicore string matching.

    PubMed

    Someswara Rao, Chinta; Raju, S Viswanadha

    2016-03-01

    Next generation sequencing (NGS) technologies have been rapidly applied in biomedical and biological research in recent years. To provide the comprehensive NGS resource for the research, in this paper , we have considered 10 loci/codi/repeats TAGA, TCAT, GAAT, AGAT, AGAA, GATA, TATC, CTTT, TCTG and TCTA. Then we developed the NGS Tandem Repeat Database (TandemRepeatDB) for all the chromosomes of Homo sapiens, Callithrix jacchus, Chlorocebus sabaeus, Gorilla gorilla, Macaca fascicularis, Macaca mulatta, Nomascus leucogenys, Pan troglodytes, Papio anubis and Pongo abelii genome data sets for all those locis. We find the successive occurence frequency for all the above 10 SSR (simple sequence repeats) in the above genome data sets on a chromosome-by-chromosome basis with multiple pattern 2° shaft multicore string matching.

  5. Next generation sequencing (NGS) database for tandem repeats with multiple pattern 2°-shaft multicore string matching.

    PubMed

    Someswara Rao, Chinta; Raju, S Viswanadha

    2016-03-01

    Next generation sequencing (NGS) technologies have been rapidly applied in biomedical and biological research in recent years. To provide the comprehensive NGS resource for the research, in this paper , we have considered 10 loci/codi/repeats TAGA, TCAT, GAAT, AGAT, AGAA, GATA, TATC, CTTT, TCTG and TCTA. Then we developed the NGS Tandem Repeat Database (TandemRepeatDB) for all the chromosomes of Homo sapiens, Callithrix jacchus, Chlorocebus sabaeus, Gorilla gorilla, Macaca fascicularis, Macaca mulatta, Nomascus leucogenys, Pan troglodytes, Papio anubis and Pongo abelii genome data sets for all those locis. We find the successive occurence frequency for all the above 10 SSR (simple sequence repeats) in the above genome data sets on a chromosome-by-chromosome basis with multiple pattern 2° shaft multicore string matching. PMID:26981434

  6. Impact of depressive symptoms, self-esteem and neuroticism on trajectories of overgeneral autobiographical memory over repeated trials.

    PubMed

    Kashdan, Todd B; Roberts, John E; Carlos, Erica L

    2006-04-01

    The present study examined trajectories of change in the frequency of overgeneral autobiographical memory (OGM) over the course of repeated trials, and tested whether particular dimensions of depressive symptomatology (somatic and cognitive-affective distress), self-esteem, and neuroticism account for individual differences in these trajectories. Given that depression is associated with impairments in effortful processing, we predicted that over repeated trials depression would be associated with increasingly OGM. Generalised Linear Mixed Models with Penalised Quasi-Likelihood demonstrated significant linear and quadratic trends in OGM over repeated trials, and somatic distress and self-esteem moderated these slopes. The form of these interactions suggested that somatic distress and low self-esteem primarily contribute to OGM during the second half of the trial sequence. The present findings demonstrate the value of a novel analytical approach to OGM that estimates individual trajectories of change over repeated trials.

  7. Next generation sequencing (NGS) database for tandem repeats with multiple pattern 2°-shaft multicore string matching

    PubMed Central

    Someswara Rao, Chinta; Raju, S. Viswanadha

    2016-01-01

    Next generation sequencing (NGS) technologies have been rapidly applied in biomedical and biological research in recent years. To provide the comprehensive NGS resource for the research, in this paper , we have considered 10 loci/codi/repeats TAGA, TCAT, GAAT, AGAT, AGAA, GATA, TATC, CTTT, TCTG and TCTA. Then we developed the NGS Tandem Repeat Database (TandemRepeatDB) for all the chromosomes of Homo sapiens, Callithrix jacchus, Chlorocebus sabaeus, Gorilla gorilla, Macaca fascicularis, Macaca mulatta, Nomascus leucogenys, Pan troglodytes, Papio anubis and Pongo abelii genome data sets for all those locis. We find the successive occurence frequency for all the above 10 SSR (simple sequence repeats) in the above genome data sets on a chromosome-by-chromosome basis with multiple pattern 2° shaft multicore string matching. PMID:26981434

  8. Sound-impenetrable holes in water based on acoustic complementary medium

    NASA Astrophysics Data System (ADS)

    Liu, Chenkai; Bai, Ping; Lai, Yun

    2016-09-01

    By designing a two-dimension acoustic complementary medium of water, we demonstrate the possibility of realizing a sound-impenetrable hole that can block acoustic waves in water. The complementary medium is composed of core-shell rubber cylinders in a square lattice, and possesses the exact negative values of water in both the effective density and bulk modulus at a working frequency. The effects of negative refraction as well as the sound-impenetrable hole are verified by numerical simulations. Interestingly, by introducing a small amount of loss, we find that the functionality of such a sound-impenetrable hole becomes robust and works in a broad frequency range.

  9. Effect of repeated burning on plant and soil carbon and nitrogen in cheatgrass (Bromus tectorum) dominated ecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background and Aims Fire has profound effects on ecosystem properties, but few studies have addressed the effect of repeated burns on soil nutrients, and none have been conducted in cold desert ecosystems where invasion by exotic annual grasses is resulting in greater fire frequency. In a 5 year stu...

  10. A cluster of highly polymorphic dinucleotide repeats in intron 17b of the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

    PubMed Central

    Zielenski, J; Markiewicz, D; Rininsland, F; Rommens, J; Tsui, L C

    1991-01-01

    A cluster of highly polymorphic dinucleotide repeats has been detected in intron 17b of the CFTR gene, 200 bp downstream from the preceding exon. At least 24 alleles, with sizes ranging from 7 to 56 units of a TA repeat, have been identified in a panel of 92 unrelated carriers of cystic fibrosis (CF). The common ones are those with 7, 30, and 31 dinucleotide units, with frequencies of .22, .19, and .12, respectively, among the non-CF chromosomes. Mendelian, codominant segregation of the alleles has been demonstrated in family studies, as expected. A less polymorphic dinucleotide (CA repeat) cluster has also been detected in a region 167 bp downstream from the TA repeat. The length of the CA repeat cluster varies from 11 to 17 dinucleotide units, and it appears to have an inverse relationship to that of the TA repeats. These dinucleotide repeats should be useful in genetic linkage studies, in counseling for CF families with unknown mutations, and in tracing the origins of the various mutant CF alleles. Images Figure 2 Figure 3 PMID:1720926

  11. Effects of repeated fires on ecosystem C and N stocks along a fire induced forest/grassland gradient

    NASA Astrophysics Data System (ADS)

    Cheng, Chih-Hsin; Chen, Yung-Sheng; Huang, Yu-Hsuan; Chiou, Chyi-Rong; Lin, Chau-Chih; Menyailo, Oleg V.

    2013-03-01

    Repeated fires might have different effect on ecosystem carbon storage than a single fire event, but information on repeated fires and their effects on forest ecosystems and carbon storage is scarce. However, changes in climate, vegetation composition, and human activities are expected to make forests more susceptible to fires that recur with relatively high frequency. In this study, the effects of repeated fires on ecosystem carbon and nitrogen stocks were examined along a fire-induced forest/grassland gradient wherein the fire events varied from an unburned forest to repeatedly burned grassland. Results from the study show repeated fires drastically decreased ecosystem carbon and nitrogen stocks along the forest/grassland gradient. The reduction began with the disappearance of living tree biomass, and followed by the loss of soil carbon and nitrogen. Within 4 years of the onset of repeated fires on the unburned forest, the original ecosystem carbon and nitrogen stocks were reduced by 42% and 21%, respectively. Subsequent fires caused cumulative reductions in ecosystem carbon and nitrogen stocks by 68% and 44% from the original ecosystem carbon and nitrogen stocks, respectively. The analyses of carbon budgets calculated by vegetation composition and stable isotopic δ13C values indicate that 84% of forest-derived carbon is lost at grassland, whereas the gain of grass-derived carbon only compensates 18% for this loss. Such significant losses in ecosystem carbon and nitrogen stocks suggest that the effects of repeated fires have substantial impacts on ecosystem and soil carbon and nitrogen cycling.

  12. Who Repeats Algebra, and How Does Initial Performance Relate to Improvement When the Course Is Repeated?

    ERIC Educational Resources Information Center

    Fong, Anthony; Jaquet, Karina; Finkelstein, Neal

    2016-01-01

    The information provided in this report shows how students perform when they repeat algebra I and how the level of improvement varies depending on initial course performance and the academic measure (course grades or CST scores). This information can help inform decisions and policies regarding whether and under what circumstances students should…

  13. Repeat Testing Effects on Credentialing Exams: Are Repeaters Misinformed or Uninformed?

    ERIC Educational Resources Information Center

    Feinberg, Richard A.; Raymond, Mark R.; Haist, Steven A.

    2015-01-01

    To mitigate security concerns and unfair score gains, credentialing programs routinely administer new test material to examinees retesting after an initial failing attempt. Counterintuitively, a small but growing body of recent research suggests that repeating the identical form does not create an unfair advantage. This study builds upon and…

  14. The Circumgalactic Medium of Quasars

    NASA Astrophysics Data System (ADS)

    Hennawi, Joe

    2014-07-01

    I will argue that observations of the diffuse gas in the outskirts of quasar host galaxies, or the so called circumgalactic medium, are essential for understanding how luminous quasars evolve in a cosmological context. Such observations also provide a fruitful comparison to theory, because hydrodynamics at moderate overdensities is much easier to simulate than the complicated processes which trigger quasar activity. A novel technique will be introduced, whereby a foreground quasar can be studied in absorption against a background quasar, resolving scales as small as 30 kpc. This experiment reveals a rich absorption spectrum which contains a wealth of information about the physical conditions of diffuse gas around quasars. Hydrodynamical simulations of the massive dark matter halos which host luminous quasars under predict the amount of cool gas observed in quasar environs by a large factor, challenging our understanding of how massive galaxies form. I will also discuss a very sensitive search for Ly-alpha emission from the same gas which we study in absorption.

  15. Studies in medium energy physics

    SciTech Connect

    Green, A.; Hoffmann, G.W.; McDonough, J.; Purcell, M.J.; Ray, R.L.; Read, D.E.; Worn, S.D.

    1991-12-01

    This document constitutes the (1991--1992) technical progress report and continuation proposal for the ongoing medium energy nuclear physics research program supported by the US Department of Energy through special Research Grant DE-FG05-88ER40444. The experiments discussed are conducted at the Los Alamos National Laboratory's (LANL) Clinton P. Anderson Meson Physics Facility (LAMPF) and the Alternating Gradient Synchrotron (AGS) facility of the Brookhaven National Laboratory (BNL). The overall motivation for the work discussed in this document is driven by three main objectives: (1) provide hadron-nucleon and hadron-nucleus scattering data which serve to facilitate the study of effective two-body interactions, test (and possibly determine) nuclear structure, and help study reaction mechanisms and dynamics; (2) provide unique, first-of-a-kind exploratory'' hadron-nucleus scattering data in the hope that such data will lead to discovery of new phenomena and new physics; and (3) perform precision tests of fundamental interactions, such as rare decay searches, whose observation would imply fundamental new physics.

  16. Terahertz scattering by granular composite materials: An effective medium theory

    NASA Astrophysics Data System (ADS)

    Kaushik, Mayank; Ng, Brian W.-H.; Fischer, Bernd M.; Abbott, Derek

    2012-01-01

    Terahertz (THz) spectroscopy and imaging have emerged as important tools for identification and classification of various substances, which exhibit absorption characteristics at distinct frequencies in the THz range. The spectral fingerprints can potentially be distorted or obscured by electromagnetic scattering caused by the granular nature of some substances. In this paper, we present THz time domain transmission measurements of granular polyethylene powders in order to investigate an effective medium theory that yields a parameterized model, which can be used to estimate the empirical measurements to good accuracy.

  17. Tunneling properties of nonplanar molecules in a gas medium

    SciTech Connect

    Bahrami, Mohammad; Bassi, Angelo

    2011-12-15

    We propose a simple, general, and accurate formula for analyzing the tunneling between classical configurations of a nonplanar molecule in a gas medium, as a function of the thermodynamic parameters of the gas. We apply it to two interesting cases: (i) the shift to zero frequency of the inversion line of ammonia, upon an increase in the pressure of the gas; and (ii) the destruction of the coherent tunneling of D{sub 2}S{sub 2} molecules in a He gas. In both cases, we compare our analysis with previous theoretical and experimental results.

  18. Semiconductor structures for repeated velocity overshoot

    NASA Astrophysics Data System (ADS)

    Cooper, J. A., Jr.; Capasso, F.; Thornber, K. K.

    1982-12-01

    The conditions required for obtaining repeated velocity overshoot in semiconductors are discussed. Two classes of structures that provide these conditions are considered. The structures are seen as holding promise for achieving average drift velocities well in excess of the maximum steady-state velocity over distances ranging from submicron to tens of microns. In structures of the first class, the stairstep in potential is achieved by using a graded bandgap that is similar to the avalanche photodetector described by Williams et al. (1982), where the composition is graded from GaAs to Al(0.2)Ga(0.8)As. The second class of structures uses alternating planar doped charge sheets, as described by Malik et al. (1980).

  19. Design principles for efficient, repeated jumpgliding.

    PubMed

    Desbiens, Alexis Lussier; Pope, Morgan T; Christensen, David L; Hawkes, Elliot W; Cutkosky, Mark R

    2014-06-01

    Combined jumping and gliding locomotion, or 'jumpgliding', can be an efficient way for small robots or animals to travel over cluttered terrain. This paper presents functional requirements and models for a simple jumpglider which formalize the benefits and limitations of using aerodynamic surfaces to augment jumping ability. Analysis of the model gives insight into design choices and control strategies for higher performance and to accommodate special conditions such as a slippery launching surface. The model informs the design of a robotic platform that can perform repeated jumps using a carbon fiber spring and a pivoting wing. Experiments with two different versions of the platform agree with predictions from the model and demonstrate a significantly greater range, and lower cost-of-transport, than a comparable ballistic jumper.

  20. Simple sequence repeats in bryophyte mitochondrial genomes.

    PubMed

    Zhao, Chao-Xian; Zhu, Rui-Liang; Liu, Yang

    2016-01-01

    Simple sequence repeats (SSRs) are thought to be common in plant mitochondrial (mt) genomes, but have yet to be fully described for bryophytes. We screened the mt genomes of two liverworts (Marchantia polymorpha and Pleurozia purpurea), two mosses (Physcomitrella patens and Anomodon rugelii) and two hornworts (Phaeoceros laevis and Nothoceros aenigmaticus), and detected 475 SSRs. Some SSRs are found conserved during the evolution, among which except one exists in both liverworts and mosses, all others are shared only by the two liverworts, mosses or hornworts. SSRs are known as DNA tracts having high mutation rates; however, according to our observations, they still can evolve slowly. The conservativeness of these SSRs suggests that they are under strong selection and could play critical roles in maintaining the gene functions.

  1. Aging and repeated thought suppression success.

    PubMed

    Lambert, Ann E; Smyth, Frederick L; Beadel, Jessica R; Teachman, Bethany A

    2013-01-01

    Intrusive thoughts and attempts to suppress them are common, but while suppression may be effective in the short-term, it can increase thought recurrence in the long-term. Because intentional suppression involves controlled processing, and many aspects of controlled processing decline with age, age differences in thought suppression outcomes may emerge, especially over repeated thought suppression attempts as cognitive resources are expended. Using multilevel modeling, we examined age differences in reactions to thought suppression attempts across four thought suppression sequences in 40 older and 42 younger adults. As expected, age differences were more prevalent during suppression than during free monitoring periods, with younger adults indicating longer, more frequent thought recurrences and greater suppression difficulty. Further, younger adults' thought suppression outcomes changed over time, while trajectories for older adults' were relatively stable. Results are discussed in terms of older adults' reduced thought recurrence, which was potentially afforded by age-related changes in reactive control and distractibility.

  2. [The repeat reliability of somatosensory evoked potentials].

    PubMed

    Strenge, H

    1989-09-01

    The test-immediate-retest reliability of latency and amplitude values of cervical and cortical somatosensory evoked potentials (SEP) to median nerve stimulation was assessed in 86 normal subjects aged 15 to 71 years. In addition to the stability of data between repeat trials within one test session the standard errors of measurement and the interpretable differences for SEP measures were calculated according to measurement theory. The study revealed retest correlations rtt greater than 0.80 for all latency measures of the cervical and cortical SEPs and all cortical amplitude parameters. The highest stability was found for the latency measures of the cervical components P10, N11, N13, the cortical components P16 and N20 and for the amplitude N20/P25. PMID:2507277

  3. Trochlear Nerve Schwannoma With Repeated Intratumoral Hemorrhage.

    PubMed

    Liu, Pengfei; Bao, Yuhai; Zhang, Wenchuan

    2016-09-01

    Trochlear nerve schwannoma is extremely rare, with only 35 pathologically confirmed patients being reported in the literature. Here, the authors report a patient of trochlear nerve schwannoma in the prepontine cistern manifesting as facial pain and double vision and presenting the image characteristics of repeated intratumoral hemorrhage, which has never been reported in the literature. Total tumor along with a portion of the trochlear nerve was removed by using a retrosigmoid approach. Facial pain disappeared after operation, and the diplopia remained. Follow-up studies have shown no tumor recurrence for 2 years and the simultaneous alleviation of diplopia. Information regarding the clinical presentation, radiological features and surgical outcomes of trochlear nerve schwannoma are discussed and reviewed in the paper. PMID:27607129

  4. Hybrid quantum repeater using bright coherent light.

    PubMed

    van Loock, P; Ladd, T D; Sanaka, K; Yamaguchi, F; Nemoto, Kae; Munro, W J; Yamamoto, Y

    2006-06-23

    We describe a quantum repeater protocol for long-distance quantum communication. In this scheme, entanglement is created between qubits at intermediate stations of the channel by using a weak dispersive light-matter interaction and distributing the outgoing bright coherent-light pulses among the stations. Noisy entangled pairs of electronic spin are then prepared with high success probability via homodyne detection and postselection. The local gates for entanglement purification and swapping are deterministic and measurement-free, based upon the same coherent-light resources and weak interactions as for the initial entanglement distribution. Finally, the entanglement is stored in a nuclear-spin-based quantum memory. With our system, qubit-communication rates approaching 100 Hz over 1280 km with fidelities near 99% are possible for reasonable local gate errors.

  5. Transcription of AAT•ATT Triplet Repeats in Escherichia coli Is Silenced by H-NS and IS1E Transposition

    PubMed Central

    Pan, Xuefeng; Liao, Lingni; Yang, Li; Li, Hongquan

    2010-01-01

    Background The trinucleotide repeats AAT•ATT are simple DNA sequences that potentially form different types of non-B DNA secondary structures and cause genomic instabilities in vivo. Methodology and Principal Findings The molecular mechanism underlying the maintenance of a 24-triplet AAT•ATT repeat was examined in E.coli by cloning the repeats into the EcoRI site in plasmid pUC18 and into the attB site on the E.coli genome. Either the AAT or the ATT strand acted as lagging strand template in a replication fork. Propagations of the repeats in either orientation on plasmids did not affect colony morphology when triplet repeat transcription using the lacZ promoter was repressed either by supplementing LacIQ in trans or by adding glucose into the medium. In contrast, transparent colonies were formed by inducing transcription of the repeats, suggesting that transcription of AAT•ATT repeats was toxic to cell growth. Meanwhile, significant IS1E transposition events were observed both into the triplet repeats region proximal to the promoter side, the promoter region of the lacZ gene, and into the AAT•ATT region itself. Transposition reversed the transparent colony phenotype back into healthy, convex colonies. In contrast, transcription of an 8-triplet AAT•ATT repeat in either orientation on plasmids did not produce significant changes in cell morphology and did not promote IS1E transposition events. We further found that a role of IS1E transposition into plasmids was to inhibit transcription through the repeats, which was influenced by the presence of the H-NS protein, but not of its paralogue StpA. Conclusions and Significance Our findings thus suggest that the longer AAT•ATT triplet repeats in E.coli become vulnerable after transcription. H-NS and its facilitated IS1E transposition can silence long triplet repeats transcription and preserve cell growth and survival. PMID:21151567

  6. Interpretations of Frequency Domain Analyses of Neural Entrainment: Periodicity, Fundamental Frequency, and Harmonics

    PubMed Central

    Zhou, Hong; Melloni, Lucia; Poeppel, David; Ding, Nai

    2016-01-01

    Brain activity can follow the rhythms of dynamic sensory stimuli, such as speech and music, a phenomenon called neural entrainment. It has been hypothesized that low-frequency neural entrainment in the neural delta and theta bands provides a potential mechanism to represent and integrate temporal information. Low-frequency neural entrainment is often studied using periodically changing stimuli and is analyzed in the frequency domain using the Fourier analysis. The Fourier analysis decomposes a periodic signal into harmonically related sinusoids. However, it is not intuitive how these harmonically related components are related to the response waveform. Here, we explain the interpretation of response harmonics, with a special focus on very low-frequency neural entrainment near 1 Hz. It is illustrated why neural responses repeating at f Hz do not necessarily generate any neural response at f Hz in the Fourier spectrum. A strong neural response at f Hz indicates that the time scales of the neural response waveform within each cycle match the time scales of the stimulus rhythm. Therefore, neural entrainment at very low frequency implies not only that the neural response repeats at f Hz but also that each period of the neural response is a slow wave matching the time scale of a f Hz sinusoid. PMID:27375465

  7. Interpretations of Frequency Domain Analyses of Neural Entrainment: Periodicity, Fundamental Frequency, and Harmonics.

    PubMed

    Zhou, Hong; Melloni, Lucia; Poeppel, David; Ding, Nai

    2016-01-01

    Brain activity can follow the rhythms of dynamic sensory stimuli, such as speech and music, a phenomenon called neural entrainment. It has been hypothesized that low-frequency neural entrainment in the neural delta and theta bands provides a potential mechanism to represent and integrate temporal information. Low-frequency neural entrainment is often studied using periodically changing stimuli and is analyzed in the frequency domain using the Fourier analysis. The Fourier analysis decomposes a periodic signal into harmonically related sinusoids. However, it is not intuitive how these harmonically related components are related to the response waveform. Here, we explain the interpretation of response harmonics, with a special focus on very low-frequency neural entrainment near 1 Hz. It is illustrated why neural responses repeating at f Hz do not necessarily generate any neural response at f Hz in the Fourier spectrum. A strong neural response at f Hz indicates that the time scales of the neural response waveform within each cycle match the time scales of the stimulus rhythm. Therefore, neural entrainment at very low frequency implies not only that the neural response repeats at f Hz but also that each period of the neural response is a slow wave matching the time scale of a f Hz sinusoid. PMID:27375465

  8. In situ detection of tandem DNA repeat length

    SciTech Connect

    Yaar, R.; Szafranski, P.; Cantor, C.R.; Smith, C.L.

    1996-11-01

    A simple method for scoring short tandem DNA repeats is presented. An oligonucleotide target, containing tandem repeats embedded in a unique sequence, was hybridized to a set of complementary probes, containing tandem repeats of known lengths. Single-stranded loop structures formed on duplexes containing a mismatched (different) number of tandem repeats. No loop structure formed on duplexes containing a matched (identical) number of tandem repeats. The matched and mismatched loop structures were enzymatically distinguished and differentially labeled by treatment with S1 nuclease and the Klenow fragment of DNA polymerase. 7 refs., 4 figs.

  9. Mutational dynamics of short tandem repeats in human genome

    NASA Astrophysics Data System (ADS)

    Borstnik, B.; Pumpernik, D.

    2004-01-01

    The evolutionary dynamics of short tandem repeats of nucleotide sequences of the human genome is studied. It is shown that a model due to which the evolutionary repeat dynamics consists of elongations and shortenings of the repeats, combined with point mutations, is degenerate in the sense that an ambiguity exists regarding the role of point mutations and slippage asymmetry. By introducing a measure of the correlations between the positions of the repeats along the DNA sequences we were able to remove the degeneracy and to show that the slippage events which are the main factor in repeat evolution exhibit more frequent shortenings than elongations.

  10. Locating tandem repeats in weighted sequences in proteins.

    PubMed

    Zhang, Hui; Guo, Qing; Iliopoulos, Costas S

    2013-01-01

    A weighted biological sequence is a string in which a set of characters may appear at each position with respective probabilities of occurrence. We attempt to locate all the tandem repeats in a weighted sequence. A repeated substring is called a tandem repeat if each occurrence of the substring is directly adjacent to each other. By introducing the idea of equivalence classes in weighted sequences, we identify the tandem repeats of every possible length using an iterative partitioning technique. We also present the algorithm for recording the tandem repeats, and prove that the problem can be solved in O(n²) time. PMID:23815711

  11. Frequency stability review

    NASA Technical Reports Server (NTRS)

    Greenhall, C. A.

    1987-01-01

    Certain aspects of the description and measurement of oscillator stability are treated. Topics covered are time and frequency deviations, Allan variance, the zero-crossing counter measurement technique, frequency drift removal, and the three-cornered hat.

  12. The performance of dense medium processes

    SciTech Connect

    Horsfall, D.W.

    1993-12-31

    Dense medium washing in baths and cyclones is widely carried out in South Africa. The paper shows the reason for the preferred use of dense medium processes rather than gravity concentrators such as jigs. The factors leading to efficient separation in baths are listed and an indication given of the extent to which these factors may be controlled and embodied in the deployment of baths and dense medium cyclones in the planning stages of a plant.

  13. Modeling Frequency Comb Sources

    NASA Astrophysics Data System (ADS)

    Li, Feng; Yuan, Jinhui; Kang, Zhe; Li, Qian; Wai, P. K. A.

    2016-06-01

    Frequency comb sources have revolutionized metrology and spectroscopy and found applications in many fields. Stable, low-cost, high-quality frequency comb sources are important to these applications. Modeling of the frequency comb sources will help the understanding of the operation mechanism and optimization of the design of such sources. In this paper,we review the theoretical models used and recent progress of the modeling of frequency comb sources.

  14. Studies of an expanded trinucleotide repeat in transgenic mice

    SciTech Connect

    Bingham, P.; Wang, S.; Merry, D.

    1994-09-01

    Spinal and bulbar muscular atrophy (SBMA) is a progressive motor neuron disease caused by expansion of a trinucleotide repeat in the androgen receptor gene (AR{sup exp}). AR{sup exp} repeats expand further or contract in approximately 25% of transmissions. Analogous {open_quotes}dynamic mutations{close_quotes} have been reported in other expanded trinucleotide repeat disorders. We have been developing a mouse model of this disease using a transgenic approach. Expression of the SBMA AR was documented in transgenic mice with an inducible promoter. No phenotypic effects of transgene expression were observed. We have extended our previous results on stability of the expanded trinucleotide repeat in transgenic mice in two lines carrying AR{sup exp}. Tail DNA was amplified by PCR using primers spanning the repeat on 60 AR{sup exp} transgenic mice from four different transgenic lines. Migration of the PCR product through an acrylamide gel showed no change of the 45 CAG repeat length in any progeny. Similarly, PCR products from 23 normal repeat transgenics showed no change from the repeat length of the original construct. Unlike the disease allele in humans, the expanded repeat AR cDNA in transgenic mice showed no change in repeat length with transmission. The relative stability of CAG repeats seen in the transgenic mice may indicate either differences in the fidelity of replicative enzymes, or differences in error identification and repair between mice and humans. Integration site or structural properties of the transgene itself might also play a role.

  15. Analysis of separate isolates of Bordetella pertussis repeated DNA sequences.

    PubMed

    McPheat, W L; Hanson, J H; Livey, I; Robertson, J S

    1989-06-01

    Two independent isolates of a Bordetella pertussis repeated DNA unit were sequenced and shown to be an insertion sequence element with five nucleotide differences between the two copies. The sequences were 1053 bp in length with near-perfect terminal inverted repeats of 28 bp, had three open reading frames, and were each flanked by short direct repeats. The two insertion sequences showed considerable homology to two other B. pertussis repeated DNA sequences reported recently: IS481 and a 530 bp repeated DNA unit. The B. pertussis insertion sequence would appear to comprise a group of closely related sequences differing mainly in flanking direct repeats and the terminal inverted repeats. The two isolates reported here, which were from the adenylate cyclase and agglutinogen 2 regions of the genome, were numbered IS48lvl and IS48lv2 respectively. PMID:2559151

  16. Structural and Energetic Characterization of the Ankyrin Repeat Protein Family

    PubMed Central

    Parra, R. Gonzalo; Espada, Rocío; Verstraete, Nina; Ferreiro, Diego U.

    2015-01-01

    Ankyrin repeat containing proteins are one of the most abundant solenoid folds. Usually implicated in specific protein-protein interactions, these proteins are readily amenable for design, with promising biotechnological and biomedical applications. Studying repeat protein families presents technical challenges due to the high sequence divergence among the repeating units. We developed and applied a systematic method to consistently identify and annotate the structural repetitions over the members of the complete Ankyrin Repeat Protein Family, with increased sensitivity over previous studies. We statistically characterized the number of repeats, the folding of the repeat-arrays, their structural variations, insertions and deletions. An energetic analysis of the local frustration patterns reveal the basic features underlying fold stability and its relation to the functional binding regions. We found a strong linear correlation between the conservation of the energetic features in the repeat arrays and their sequence variations, and discuss new insights into the organization and function of these ubiquitous proteins. PMID:26691182

  17. How Soft Gamma Repeaters Might Make Fast Radio Bursts

    NASA Astrophysics Data System (ADS)

    Katz, J. I.

    2016-08-01

    There are several phenomenological similarities between soft gamma repeaters (SGRs) and fast radio bursts (FRBs), including duty factors, timescales, and repetition. The sudden release of magnetic energy in a neutron star magnetosphere, as in popular models of SGRs, can meet the energy requirements of FRBs, but requires both the presence of magnetospheric plasma, in order for dissipation to occur in a transparent region, and a mechanism for releasing much of that energy quickly. FRB sources and SGRs are distinguished by long-lived (up to thousands of years) current-carrying coronal arches remaining from the formation of the young neutron star, and their decay ends the phase of SGR/AXP/FRB activity even though “magnetar” fields may persist. Runaway increases in resistance when the current density exceeds a threshold, releases magnetostatic energy in a sudden burst, and produces high brightness GHz emission of FRB by a coherent process. SGRs are produced when released energy thermalizes as an equlibrium pair plasma. The failures of some alternative FRB models and the non-detection of SGR 1806-20 at radio frequencies are discussed in the appendices.

  18. Building icelandic igneous crust by repeated melt injections

    NASA Astrophysics Data System (ADS)

    Greenfield, Tim; White, Robert S.

    2015-11-01

    Observations of microseismicity provide a powerful tool for mapping the movement of melt in the crust. Here we record remarkable sequences of earthquakes 20 km below the surface in the normally ductile crust in the vicinity of Askja Volcano, in northeast Iceland. The earthquakes occur in swarms consisting of identical waveforms repeating as frequently as every 8 s for up to 3 h. We use template waveforms from each swarm to detect and locate earthquakes with an automated cross-correlation technique. Events are located in the lower crust and are inferred to be the result of melt being injected into the crust. During melt intrusion high strain rates are produced in conjunction with high pore fluid pressures from the melt or exsolved carbon dioxide. These cause brittle failure on high-angle fault planes located at the tips of sills. Moment tensor solutions show that most of the earthquakes are opening cracks accompanied by volumetric increases. This is consistent with the failure causing the earthquakes by melt injection opening new tensile cracks. Analysis of the magnitude distribution of earthquakes within a swarm reveals a complicated relationship between the imposed strain rates and the fluids that cause brittle failure. The magnitude of the earthquakes is controlled by the distance fluids can migrate along a fault, whereas the frequency of the events is controlled by the strain rate. Faults at the tips of sills act to focus melt transport between sills and so must be an important method of transporting melt through the lower crust.

  19. Chemically defined medium and Caenorhabditis elegans

    NASA Technical Reports Server (NTRS)

    Szewczyk, Nathaniel J.; Kozak, Elena; Conley, Catharine A.

    2003-01-01

    BACKGROUND: C. elegans has been established as a powerful genetic system. Use of a chemically defined medium (C. elegans Maintenance Medium (CeMM)) now allows standardization and systematic manipulation of the nutrients that animals receive. Liquid cultivation allows automated culturing and experimentation and should be of use in large-scale growth and screening of animals. RESULTS: We find that CeMM is versatile and culturing is simple. CeMM can be used in a solid or liquid state, it can be stored unused for at least a year, unattended actively growing cultures may be maintained longer than with standard techniques, and standard C. elegans protocols work well with animals grown in defined medium. We also find that there are caveats to using defined medium. Animals in defined medium grow more slowly than on standard medium, appear to display adaptation to the defined medium, and display altered growth rates as they change the composition of the defined medium. CONCLUSIONS: As was suggested with the introduction of C. elegans as a potential genetic system, use of defined medium with C. elegans should prove a powerful tool.

  20. Eastern Frequency Response Study

    SciTech Connect

    Miller, N.W.; Shao, M.; Pajic, S.; D'Aquila, R.

    2013-05-01

    This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

  1. Frequency Response Tool

    SciTech Connect

    Etingov, Pavel; Chassin, PNNL David; Zhang, PNNL Yu; PNNL,

    2014-03-13

    According to the North American Electric Reliability Corporation (NERC) definition: “Frequency response is a measure of an Interconnection’s ability to stabilize frequency immediately following the sudden loss of generation or load, and is a critical component of the reliable operation of the Bulk-Power System, particularly during disturbances and recoveries. Failure to maintain frequency can disrupt the operation of equipment and initiate disconnection of power plant equipment to prevent it from being damaged, which could lead to wide-spread blackouts.” Frequency Response Tool automates the power system frequency response analysis process. The tool performs initial estimation of the system frequency parameters (initial frequency, minimum frequency, settling point). User can visually inspect and adjust these parameters. The tool also calculates the frequency response performance metrics of the system, archives the historic events and baselines the system performance. Frequency response performance characteristics of the system are calculated using phasor measurement unit (PMU) information. Methodology of the frequency response performance assessment implemented in the tool complies with the NERC Frequency response standard.

  2. Frequency Response Tool

    2014-03-13

    According to the North American Electric Reliability Corporation (NERC) definition: “Frequency response is a measure of an Interconnection’s ability to stabilize frequency immediately following the sudden loss of generation or load, and is a critical component of the reliable operation of the Bulk-Power System, particularly during disturbances and recoveries. Failure to maintain frequency can disrupt the operation of equipment and initiate disconnection of power plant equipment to prevent it from being damaged, which could leadmore » to wide-spread blackouts.” Frequency Response Tool automates the power system frequency response analysis process. The tool performs initial estimation of the system frequency parameters (initial frequency, minimum frequency, settling point). User can visually inspect and adjust these parameters. The tool also calculates the frequency response performance metrics of the system, archives the historic events and baselines the system performance. Frequency response performance characteristics of the system are calculated using phasor measurement unit (PMU) information. Methodology of the frequency response performance assessment implemented in the tool complies with the NERC Frequency response standard.« less

  3. The Accuracy, Feasibility and Challenges of Sequencing Short Tandem Repeats Using Next-Generation Sequencing Platforms

    PubMed Central

    Zavodna, Monika; Bagshaw, Andrew; Brauning, Rudiger; Gemmell, Neil J.

    2014-01-01

    To date we have little knowledge of how accurate next-generation sequencing (NGS) technologies are in sequencing repetitive sequences beyond known limitations to accurately sequence homopolymers. Only a handful of previous reports have evaluated the potential of NGS for sequencing short tandem repeats (microsatellites) and no empirical study has compared and evaluated the performance of more than one NGS platform with the same dataset. Here we examined yeast microsatellite variants from both long-read (454-sequencing) and short-read (Illumina) NGS platforms and compared these to data derived through Sanger sequencing. In addition, we investigated any locus-specific biases and differences that might have resulted from variability in microsatellite repeat number, repeat motif or type of mutation. Out of 112 insertion/deletion variants identified among 45 microsatellite amplicons in our study, we found 87.5% agreement between the 454-platform and Sanger sequencing in frequency of variant detection after Benjamini-Hochberg correction for multiple tests. For a subset of 21 microsatellite amplicons derived from Illumina sequencing, the results of short-read platform were highly consistent with the other two platforms, with 100% agreement with 454-sequencing and 93.6% agreement with the Sanger method after Benjamini-Hochberg correction. We found that the microsatellite attributes copy number, repeat motif and type of mutation did not have a significant effect on differences seen between the sequencing platforms. We show that both long-read and short-read NGS platforms can be used to sequence short tandem repeats accurately, which makes it feasible to consider the use of these platforms in high-throughput genotyping. It appears the major requirement for achieving both high accuracy and rare variant detection in microsatellite genotyping is sufficient read depth coverage. This might be a challenge because each platform generates a consistent pattern of non-uniform sequence

  4. Nonlinear site response in medium magnitude earthquakes near Parkfield, California

    USGS Publications Warehouse

    Rubinstein, Justin L.

    2011-01-01

    Careful analysis of strong-motion recordings of 13 medium magnitude earthquakes (3.7 ≤ M ≤ 6.5) in the Parkfield, California, area shows that very modest levels of shaking (approximately 3.5% of the acceleration of gravity) can produce observable changes in site response. Specifically, I observe a drop and subsequent recovery of the resonant frequency at sites that are part of the USGS Parkfield dense seismograph array (UPSAR) and Turkey Flat array. While further work is necessary to fully eliminate other models, given that these frequency shifts correlate with the strength of shaking at the Turkey Flat array and only appear for the strongest shaking levels at UPSAR, the most plausible explanation for them is that they are a result of nonlinear site response. Assuming this to be true, the observation of nonlinear site response in small (M M 6.5 San Simeon earthquake and the 2004 M 6 Parkfield earthquake).

  5. Spheroidizing of medium carbon steels

    NASA Astrophysics Data System (ADS)

    O'Brien, James Michael

    2000-11-01

    An investigation has been made of spheroidization of medium carbon steels used in the bolt industry. Two process cycles were considered. One was the intercritical cycle, widely used in industry, in which the steel was heated above the A1 temperature for approximately 2 hours and then cooled to 688°C (1270°F) and held for various periods. The other was a subcritical cycle that involved heating to 704°C (1300°F) for various times. Wire samples were 0.4-in. diameter AISI 1541, considered high in manganese and difficult to spheroidize. Although AISI 4037 is considered easier to spheroidize, this alloy was also tested due to its extensive industrial use. It was found that the intercritical cycle produced a somewhat faster drop in hardness. However, one hour of the subcritical cycle yielded greater ductility than 32 hours of the intercritical process, as measured by tensile tests. Similar ductility results were achieved using a new flare test. The level of spheroidization was defined in this study to be the percentage of carbide particles with aspect ratios less than 3. The subcritical cycle produced the same level of spheroidization in 1/2 hour as that reached by the intercritical cycle in 32 hours. Faster spheroidization of cementite plates in the subcritical process appears to be due to the fine pearlite generated by the current practice of rapid cooling off the hot mill. This advantage is lost in the intercritical process because the original pearlite is dissolved above the A1 temperature.

  6. Harmonic Frequency Lowering

    PubMed Central

    Kirchberger, Martin

    2016-01-01

    A novel algorithm for frequency lowering in music was developed and experimentally tested in hearing-impaired listeners. Harmonic frequency lowering (HFL) combines frequency transposition and frequency compression to preserve the harmonic content of music stimuli. Listeners were asked to make judgments regarding detail and sound quality in music stimuli. Stimuli were presented under different signal processing conditions: original, low-pass filtered, HFL, and nonlinear frequency compressed. Results showed that participants reported perceiving the most detail in the HFL condition. In addition, there was no difference in sound quality across conditions. PMID:26834122

  7. Regional flood frequency analysis

    SciTech Connect

    Singh, V.P.

    1987-01-01

    This book, the fourth of a four volume set, contains five sections encompassing major aspects of regional flood frequency analysis. Each section starts usually with an invited state-of-the-art paper followed by contributed papers. The first section provides an assessment of regional flood frequency analysis. Methods for performing regional frequency analysis for ungaged watersheds are presented in Section 2. More discussion on regional frequency analysis is provided in Section 3. Selection and comparison of regional frequency methods are dealt with in Section 4; these are of great interest to the user. Increasing attention is being focused these days on paleohydrologic flood analysis. This topic is covered in Section 5.

  8. Frequency selective infrared sensors

    SciTech Connect

    Davids, Paul; Peters, David W

    2014-11-25

    A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

  9. Frequency selective infrared sensors

    DOEpatents

    Davids, Paul; Peters, David W

    2013-05-28

    A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

  10. Frequency discriminator/phase detector

    NASA Technical Reports Server (NTRS)

    Crow, R. B.

    1974-01-01

    Circuit provides dual function of frequency discriminator/phase detector which reduces frequency acquisition time without adding to circuit complexity. Both frequency discriminators, in evaluated frequency discriminator/phase detector circuits, are effective two decades above and below center frequency.

  11. The CAG repeat polymorphism of mitochondrial polymerase gamma (POLG) is associated with male infertility in Tunisia.

    PubMed

    Baklouti-Gargouri, S; Ghorbel, M; Chakroun, N; Sellami, A; Fakhfakh, F; Ammar-Keskes, L

    2012-05-01

    Male fertility largely depends on sperm quality, which may be affected by environmental and genetic factors. Recent data emphasised the implication of the polymorphism of mitochondrial DNA polymerase gamma (POLG) CAG repeats in male infertility. In this report, we explored a possible role of the (POLG) gene polymorphism in male infertility in Tunisian men. The polymorphic CAG repeat in the nuclear POLG gene was studied in 339 male subjects (216 patients with infertility (69 azoospermic, 115 oligoasthenoteratospermic and 32 normospermic) and 123 fertile) after DNA amplification by PCR, followed by genotyping using an automatic sequencer. The heterozygous and the homozygous mutant genotypes (10/ ≠ 10 and ≠ 10/ ≠ 10) were significantly more frequent among infertile patients than among fertile controls (11.2% versus 1.6%, P = 1.3 × 10(-3) and 4.6% versus 0.8%, P = 4.2 × 10(-7) respectively). We also found a significant difference between the frequencies of 10/ ≠ 10 genotype in azoospermic (4.4%) and in oligoasthenoteratospermic (15.6%) infertile patients (P = 2.6 × 10(-2) ). However, the homozygous mutant genotype (≠ 10/ ≠ 10) was seen at similar frequencies in azoospermic, normospermic and oligoasthenospermic men (4.4%, 3.1% and 5.2% respectively). Under our conditions, the findings showed an association between POLG CAG repeat polymorphism and male infertility in Tunisian population.

  12. Exploring bacterial community structure and function associated with atrazine biodegradation in repeatedly treated soils.

    PubMed

    Fang, Hua; Lian, Jianjun; Wang, Huifang; Cai, Lin; Yu, Yunlong

    2015-04-01

    Substantial application of the herbicide atrazine in agriculture leads to persistent contamination, which may damage the succeeding crops and pose potential threats to soil ecology and environmental health. Here, the degradation characteristics of atrazine and dynamic change of soil bacterial community structure and function as well as their relations were studied during three repeated treatments at the recommended, double, and five-fold doses. The results showed that the degradation half-life of atrazine obviously decreased with increased treatment frequency. Soil microbial functional diversity displayed a variation trend of suppression-recovery-stimulation, which was associated with increased degradation rate of atrazine. 16S amplicon sequencing was conducted to explore bacterial community structure and correlate the genus to potential atrazine degradation. A total of seven potentially atrazine-degrading bacterial genera were found including Nocardioides, Arthrobacter, Bradyrhizobium, Burkholderia, Methylobacterium, Mycobacterium, and Clostridium. These bacterial genera showed almost complete atrazine degradation pathways including dechlorination, dealkylation, hydroxylation, and ring cleavage. Furthermore, the relative abundance of four of them (i.e., Nocardioides, Arthrobacter, Methylobacterium, and Bradyrhizobium) increased with treatment frequency and atrazine concentration, suggesting that they may participate in atrazine degradation during repeated treatments. Our findings reveal the potential relationship between atrazine degradation and soil bacterial community structure in repeatedly treated soils.

  13. In- silico exploration of thirty alphavirus genomes for analysis of the simple sequence repeats.

    PubMed

    Alam, Chaudhary Mashhood; Singh, Avadhesh Kumar; Sharfuddin, Choudhary; Ali, Safdar

    2014-12-01

    The compilation of simple sequence repeats (SSRs) in viruses and its analysis with reference to incidence, distribution and variation would be instrumental in understanding the functional and evolutionary aspects of repeat sequences. Present study encompasses the analysis of SSRs across 30 species of alphaviruses. The full length genome sequences, assessed from NCBI were used for extraction and analysis of repeat sequences using IMEx software. The repeats of different motif sizes (mono- to penta-nucleotide) observed therein exhibited variable incidence across the species. Expectedly, mononucleotide A/T was the most prevalent followed by dinucleotide AG/GA and trinucleotide AAG/GAA in these genomes. The conversion of SSRs to imperfect microsatellite or compound microsatellite (cSSR) is low. cSSR, primarily constituted by variant motifs accounted for up to 12.5% of the SSRs. Interestingly, seven species lacked cSSR in their genomes. However, the SSR and cSSR are predominantly localized to the coding region ORFs for non structural protein and structural proteins. The relative frequencies of different classes of simple and compound microsatellites within and across genomes have been highlighted.

  14. Repeatability in the contact calling system of Spix's disc-winged bat (Thyroptera tricolor)

    PubMed Central

    Chaverri, Gloriana; Gillam, Erin H.

    2015-01-01

    Spix's disc-winged bat (Thyroptera tricolor) forms cohesive groups despite using an extremely ephemeral roost, partly due to the use of two acoustic signals that help individuals locate roost sites and group members. While the calls that aid in group cohesion are commonly used, some bats rarely or never produce them. Here, we examine whether the differences observed in the contact calling behaviour of T. tricolor are repeatable; that is, whether individual differences are consistent. We recorded contact calls of individuals in the field and rates and patterns of vocalization. To determine whether measured variables were consistent within individuals, we estimated repeatability (R), which compares within-individual to among-individual variance in behavioural traits. Our results show that repeatability for call variables was moderate but significant, and that repeatability was highest for the average number of calls produced (R=0.46–0.49). Our results demonstrate important individual differences in the contact calling behaviour of T. tricolor; we discuss how these could be the result of mechanisms such as frequency-dependent selection that favour groups composed of individuals with diverse vocal strategies. Future work should address whether changes in social environment, specifically group membership and social status, affect vocal behaviour. PMID:26064578

  15. The effects of repeated intravenous iohexol administration on renal function in healthy beagles – a preliminary report

    PubMed Central

    2012-01-01

    Background Contrast induced nephrotoxicity (CIN) is a well described syndrome in humans undergoing contrast medium examinations. To date CIN has received minimal attention in the veterinary literature despite increasing use of contrast medium examinations in computed tomographic studies. Methods This prospective study evaluated the effect of 1290 mg/kg iohexol given intravenously to 5 normal beagle dogs in a divided dose at an interval of 6–8 weeks. Renal function was evaluated by means of scintigraphically determined glomerular filtration rate (GFR) and a variety of laboratory assays. Results Only GFR showed a significant decrease (17%) after the second injection but not to a clinically or pathologically significant level. Conclusions No clinically significant effect of repeated contrast medium administration was determined in this limited study. However in dogs with reduced renal function the risk of CIN is likely to increase dramatically post contrast administration. PMID:22892108

  16. Evolution of subterminal satellite (StSat) repeats in hominids.

    PubMed

    Koga, Akihiko; Notohara, Morihiro; Hirai, Hirohisa

    2011-02-01

    Subterminal satellite (StSat) repeats, consisting of 32-bp-long AT-rich units (GATATTTCCATGTT(T/C)ATACAGATAGCGGTGTA), were first found in chimpanzee and gorilla (African great apes) as one of the major components of heterochromatic regions located proximal to telomeres of chromosomes. StSat repeats have not been found in orangutan (Asian great ape) or human. This patchy distribution among species suggested that the StSat repeats were present in the common ancestor of African great apes and subsequently lost in the lineage leading to human. An alternative explanation is that the StSat repeats in chimpanzee and gorilla have different origins and the repeats did not occur in human. The purpose of the present study was quantitative evaluation of the above alternative possibilities by analyzing the nucleotide variation contained in the repeats. We collected large numbers of sequences of repeat units from genome sequence databases of chimpanzee and gorilla, and also bonobo (an African great ape phylogenetically closer to chimpanzee). We then compared the base composition of the repeat units among the 3 species, and found statistically significant similarities in the base composition. These results support the view that the StSat repeats had already formed multiple arrays in the common ancestor of African great apes. It is thus suggested that humans lost StSat repeats which had once grown to multiple arrays.

  17. Hidden ancient repeats in DNA: mapping and quantification.

    PubMed

    Frenkel, Zakharia M; Barzily, Zeev; Volkovich, Zeev; Trifonov, Edward N

    2013-10-10

    We have shown, in a previous paper, that tandem repeating sequences, especially triplet repeats, play a very important role in gene evolution. This result led to the formulation of the following hypothesis: most of the genomic sequences evolved through everlasting acts of tandem repeat expansions with subsequent accumulation of changes. In order to estimate how much of the observed sequences have the repeat origin we describe the adaptation of a text segmentation algorithm, based on dynamic programming, to the mapping of the ancient expansion events. The algorithm maximizes the segmentation cost, calculated as the similarity of obtained fragments to the putative repeat sequence. In the first application of the algorithm to segmentations of genomic sequences, a significant difference between the natural sequences and the corresponding shuffled sequences is detected. The natural fragments are longer and more similar to the putative repeat sequences. As our analysis shows, the coding sequences allow for repeats only when the size of the repeated words is divisible by three. In contrast, in the non-coding sequences, all repeated word sizes are present. It was estimated, that in Escherichia coli K12 genome, about 35.5% of sequence can be detectably traced to original simple repeat ancestors. The results shed light on the genomic sequence organization, and strongly confirm the hypothesis about the crucial role of triplet expansions in gene origin and evolution.

  18. Comparison of simple sequence repeats in 19 Archaea.

    PubMed

    Trivedi, S

    2006-01-01

    All organisms that have been studied until now have been found to have differential distribution of simple sequence repeats (SSRs), with more SSRs in intergenic than in coding sequences. SSR distribution was investigated in Archaea genomes where complete chromosome sequences of 19 Archaea were analyzed with the program SPUTNIK to find di- to penta-nucleotide repeats. The number of repeats was determined for the complete chromosome sequences and for the coding and non-coding sequences. Different from what has been found for other groups of organisms, there is an abundance of SSRs in coding regions of the genome of some Archaea. Dinucleotide repeats were rare and CG repeats were found in only two Archaea. In general, trinucleotide repeats are the most abundant SSR motifs; however, pentanucleotide repeats are abundant in some Archaea. Some of the tetranucleotide and pentanucleotide repeat motifs are organism specific. In general, repeats are short and CG-rich repeats are present in Archaea having a CG-rich genome. Among the 19 Archaea, SSR density was not correlated with genome size or with optimum growth temperature. Pentanucleotide density had an inverse correlation with the CG content of the genome. PMID:17183484

  19. REPdenovo: Inferring De Novo Repeat Motifs from Short Sequence Reads

    PubMed Central

    Chu, Chong; Nielsen, Rasmus; Wu, Yufeng

    2016-01-01

    Repeat elements are important components of eukaryotic genomes. One limitation in our understanding of repeat elements is that most analyses rely on reference genomes that are incomplete and often contain missing data in highly repetitive regions that are difficult to assemble. To overcome this problem we develop a new method, REPdenovo, which assembles repeat sequences directly from raw shotgun sequencing data. REPdenovo can construct various types of repeats that are highly repetitive and have low sequence divergence within copies. We show that REPdenovo is substantially better than existing methods both in terms of the number and the completeness of the repeat sequences that it recovers. The key advantage of REPdenovo is that it can reconstruct long repeats from sequence reads. We apply the method to human data and discover a number of potentially new repeats sequences that have been missed by previous repeat annotations. Many of these sequences are incorporated into various parasite genomes, possibly because the filtering process for host DNA involved in the sequencing of the parasite genomes failed to exclude the host derived repeat sequences. REPdenovo is a new powerful computational tool for annotating genomes and for addressing questions regarding the evolution of repeat families. The software tool, REPdenovo, is available for download at https://github.com/Reedwarbler/REPdenovo. PMID:26977803

  20. Frequency dependent squeezed light at audio frequencies

    NASA Astrophysics Data System (ADS)

    Miller, John

    2015-04-01

    Following successful implementation in the previous generation of instruments, squeezed states of light represent a proven technology for the reduction of quantum noise in ground-based interferometric gravitational-wave detectors. As a result of lower noise and increased circulating power, the current generation of detectors places one further demand on this technique - that the orientation of the squeezed ellipse be rotated as function of frequency. This extension allows previously negligible quantum radiation pressure noise to be mitigated in addition to quantum shot noise. I will present the results of an experiment which performs the appropriate rotation by reflecting the squeezed state from a detuned high-finesse optical cavity, demonstrating frequency dependent squeezing at audio frequencies for the first time and paving the way for broadband quantum noise reduction in Advanced LIGO. Further, I will indicate how a realistic implementation of this approach will impact Advanced LIGO both alone and in combination with other potential upgrades.

  1. Temperature Distribution in a Uniformly Moving Medium

    ERIC Educational Resources Information Center

    Mitchell, Joseph D.; Petrov, Nikola P.

    2009-01-01

    We apply several physical ideas to determine the steady temperature distribution in a medium moving with uniform velocity between two infinite parallel plates. We compute it in the coordinate frame moving with the medium by integration over the "past" to account for the influence of an infinite set of instantaneous point sources of heat in past…

  2. 49 CFR 236.811 - Speed, medium.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Speed, medium. 236.811 Section 236.811 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Speed, medium. A speed not exceeding 40 miles per hour....

  3. 49 CFR 236.811 - Speed, medium.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Speed, medium. 236.811 Section 236.811 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Speed, medium. A speed not exceeding 40 miles per hour....

  4. 49 CFR 236.811 - Speed, medium.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Speed, medium. 236.811 Section 236.811 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Speed, medium. A speed not exceeding 40 miles per hour....

  5. 49 CFR 236.811 - Speed, medium.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Speed, medium. 236.811 Section 236.811 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Speed, medium. A speed not exceeding 40 miles per hour....

  6. 49 CFR 236.811 - Speed, medium.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Speed, medium. 236.811 Section 236.811 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Speed, medium. A speed not exceeding 40 miles per hour....

  7. Generalized electromagnetic fields in a chiral medium

    NASA Astrophysics Data System (ADS)

    Bisht, P. S.; Singh, Jivan; Negi, O. P. S.

    2007-09-01

    The time-dependent Dirac-Maxwell's equations in the presence of electric and magnetic sources are reformulated in a chiral medium, and the solutions for the classical problem are obtained in a unique, simple and consistent manner. The quaternion reformulation of generalized electromagnetic fields in the chiral medium has also been discussed in a compact, simple and consistent manner.

  8. Bed-limited cracks in effective medium theory

    NASA Astrophysics Data System (ADS)

    Tod, S. R.

    2003-02-01

    An effective medium theory typically requires the description of a mean crack shape. In general, for simplicity, this is taken to be a flat, circular (`penny-shaped') crack. However, this places an unnecessary limitation on the theory, when it is perhaps more realistic to describe a crack in terms of having a bounded width and an otherwise ellipsoidal shape. The generalization of the method of smoothing, as proposed by Hudson (1994, Geophys. J. Int.,117, 555-561) , to extend his original model (Hudson, 1980. Math. proc. Camb. phil. Soc.,88, 371-384), has been used to study the role of the crack width and the ratio of the two larger dimensions in determining the properties of the effective medium. In general, this leads to a description of the medium as having orthorhombic symmetry, and provides a suitable description of a material where the crack dimensions are restricted in one direction owing to, for example, bed-limiting effects, while remaining unconfined in other directions. An elliptical flat crack limit is determined, analoguous to the circular crack description of the original Hudson model. In addition to the isolated crack description, the theory is extended to include the fluid flow mechanism of Tod (2001, Geophys. J. Int.,146, 249-263) that models the flow as being dominated by crack-to-crack flow and is valid for low matrix porosities and over a large range of frequencies, provided that the wavelength is much greater than the crack dimensions.

  9. Specificity of the Human Frequency Following Response for Carrier and Modulation Frequency Assessed Using Adaptation.

    PubMed

    Gockel, Hedwig E; Krugliak, Alexandra; Plack, Christopher J; Carlyon, Robert P

    2015-12-01

    The frequency following response (FFR) is a scalp-recorded measure of phase-locked brainstem activity to stimulus-related periodicities. Three experiments investigated the specificity of the FFR for carrier and modulation frequency using adaptation. FFR waveforms evoked by alternating-polarity stimuli were averaged for each polarity and added, to enhance envelope, or subtracted, to enhance temporal fine structure information. The first experiment investigated peristimulus adaptation of the FFR for pure and complex tones as a function of stimulus frequency and fundamental frequency (F0). It showed more adaptation of the FFR in response to sounds with higher frequencies or F0s than to sounds with lower frequency or F0s. The second experiment investigated tuning to modulation rate in the FFR. The FFR to a complex tone with a modulation rate of 213 Hz was not reduced more by an adaptor that had the same modulation rate than by an adaptor with a different modulation rate (90 or 504 Hz), thus providing no evidence that the FFR originates mainly from neurons that respond selectively to the modulation rate of the stimulus. The third experiment investigated tuning to audio frequency in the FFR using pure tones. An adaptor that had the same frequency as the target (213 or 504 Hz) did not generally reduce the FFR to the target more than an adaptor that differed in frequency (by 1.24 octaves). Thus, there was no evidence that the FFR originated mainly from neurons tuned to the frequency of the target. Instead, the results are consistent with the suggestion that the FFR for low-frequency pure tones at medium to high levels mainly originates from neurons tuned to higher frequencies. Implications for the use and interpretation of the FFR are discussed. PMID:26162415

  10. Effect of repeated evaluation and repeated exposure on acceptability ratings of sentences.

    PubMed

    Zervakis, Jennifer; Mazuka, Reiko

    2013-12-01

    This study investigated the effect of repeated evaluation and repeated exposure on grammatical acceptability ratings for both acceptable and unacceptable sentence types. In Experiment 1, subjects in the Experimental group rated multiple examples of two ungrammatical sentence types (ungrammatical binding and double object with dative-only verb), and two difficult to process sentence types [center-embedded (2) and garden path ambiguous relative], along with matched grammatical/non-difficult sentences, before rating a final set of experimental sentences. Subjects in the control group rated unrelated sentences during the exposure period before rating the experimental sentences. Subjects in the Experimental group rated both grammatical and ungrammatical sentences as more acceptable after repeated evaluation than subjects in the Control group. In Experiment 2, subjects answered a comprehension question after reading each sentence during the exposure period. Subjects in the experimental group rated garden path and center-embedded (1) sentences as higher in acceptability after comprehension exposure than subjects in the control group. The results are consistent with increased fluency of comprehension being misattributed as a change in acceptability.

  11. Effect of repeated evaluation and repeated exposure on acceptability ratings of sentences.

    PubMed

    Zervakis, Jennifer; Mazuka, Reiko

    2013-12-01

    This study investigated the effect of repeated evaluation and repeated exposure on grammatical acceptability ratings for both acceptable and unacceptable sentence types. In Experiment 1, subjects in the Experimental group rated multiple examples of two ungrammatical sentence types (ungrammatical binding and double object with dative-only verb), and two difficult to process sentence types [center-embedded (2) and garden path ambiguous relative], along with matched grammatical/non-difficult sentences, before rating a final set of experimental sentences. Subjects in the control group rated unrelated sentences during the exposure period before rating the experimental sentences. Subjects in the Experimental group rated both grammatical and ungrammatical sentences as more acceptable after repeated evaluation than subjects in the Control group. In Experiment 2, subjects answered a comprehension question after reading each sentence during the exposure period. Subjects in the experimental group rated garden path and center-embedded (1) sentences as higher in acceptability after comprehension exposure than subjects in the control group. The results are consistent with increased fluency of comprehension being misattributed as a change in acceptability. PMID:23179954

  12. Power Line Integrity Monitor and Repeater

    SciTech Connect

    Svoboda, John

    2005-09-30

    The Idaho National Laboratory (INL) has developed a power system integrity monitor and repeater that provide real time status of the integrity of the physical structure of power poles and transmission towers. It may be applied to other structures, such as pipelines or cell towers, which have multiple segments that can cover hundreds of miles. Sensors and on-board processing provide indication of tampering or impending damage to the structure with information provided to the central operations center or supervisory control and data acquisition (SCADA) for mitigative actions. This software runs on a series of small, inexpensive, low power electronic sensor platforms that are mounted on each tower of an electric power transmission or distribution system for the purpose of communicating system integrity to a central location. The software allows each platform to: 1) interface with sensors that monitor tower integrity, 2) record and analyze events, 3) communicate sensor information to other sensor platforms located on adjacent towers or to a central monitoring location, and 4) derive, conserve, and store platform power from the transmission of electric power.

  13. Repeated learning makes cultural evolution unique

    PubMed Central

    Strimling, Pontus; Enquist, Magnus; Eriksson, Kimmo

    2009-01-01

    Although genetic information is acquired only once, cultural information can be both abandoned and reacquired during an individual's lifetime. Therefore, cultural evolution will be determined not only by cultural traits' ability to spread but also by how good they are at sticking with an individual; however, the evolutionary consequences of this aspect of culture have not previously been explored. Here we show that repeated learning and multiple characteristics of cultural traits make cultural evolution unique, allowing dynamical phenomena we can recognize as specifically cultural, such as traits that both spread quickly and disappear quickly. Importantly, the analysis of our model also yields a theoretical objection to the popular suggestion that biological and cultural evolution can be understood in similar terms. We find that the possibility to predict long-term cultural evolution by some success index, analogous to biological fitness, depends on whether individuals have few or many opportunities to learn. If learning opportunities are few, we find that the existence of a success index may be logically impossible, rendering notions of “cultural fitness” meaningless. On the other hand, if individuals can learn many times, we find a success index that works, regardless of whether the transmission pattern is vertical, oblique, or horizontal. PMID:19666615

  14. Effects of repeated application of a moisturizer.

    PubMed

    Serup, J; Winther, A; Blichmann, C W

    1989-01-01

    Epidermal hydration following repeated application of an oil in water emulsion was studied on the forearm skin of 16 healthy females by non-invasive methods. The lotion was applied twice daily for 7 days, and values were followed 7 days after cessation of treatment. The opposite forearm served as an untreated control. Electrical conductance and capacitance showed similar results, i.e. increased values (p less than 0.001) after 2 days of application, reaching a plateau during further applications. Two days after cessation, values were still increased (p less than 0.001), and the conductance was also increased 7 days after cessation of treatment. The water evaporation and the cutaneous blood flow did not change, i.e. indicating no mild irritant effect. Skin surface lipids did not change, i.e. indicating that no significant amounts of emulsion oil remained on the skin at the time of recording. Probably components of the oil phase of the emulsion are absorbed into the epidermis, which is associated with improved hydration as a later event.

  15. Repeatability of published microarray gene expression analyses.

    PubMed

    Ioannidis, John P A; Allison, David B; Ball, Catherine A; Coulibaly, Issa; Cui, Xiangqin; Culhane, Aedín C; Falchi, Mario; Furlanello, Cesare; Game, Laurence; Jurman, Giuseppe; Mangion, Jon; Mehta, Tapan; Nitzberg, Michael; Page, Grier P; Petretto, Enrico; van Noort, Vera

    2009-02-01

    Given the complexity of microarray-based gene expression studies, guidelines encourage transparent design and public data availability. Several journals require public data deposition and several public databases exist. However, not all data are publicly available, and even when available, it is unknown whether the published results are reproducible by independent scientists. Here we evaluated the replication of data analyses in 18 articles on microarray-based gene expression profiling published in Nature Genetics in 2005-2006. One table or figure from each article was independently evaluated by two teams of analysts. We reproduced two analyses in principle and six partially or with some discrepancies; ten could not be reproduced. The main reason for failure to reproduce was data unavailability, and discrepancies were mostly due to incomplete data annotation or specification of data processing and analysis. Repeatability of published microarray studies is apparently limited. More strict publication rules enforcing public data availability and explicit description of data processing and analysis should be considered.

  16. Orbitofrontal cortical activity during repeated free choice.

    PubMed

    Campos, Michael; Koppitch, Kari; Andersen, Richard A; Shimojo, Shinsuke

    2012-06-01

    Neurons in the orbitofrontal cortex (OFC) have been shown to encode subjective values, suggesting a role in preference-based decision-making, although the precise relation to choice behavior is unclear. In a repeated two-choice task, subjective values of each choice can account for aggregate choice behavior, which is the overall likelihood of choosing one option over the other. Individual choices, however, are impossible to predict with knowledge of relative subjective values alone. In this study we investigated the role of internal factors in choice behavior with a simple but novel free-choice task and simultaneous recording from individual neurons in nonhuman primate OFC. We found that, first, the observed sequences of choice behavior included periods of exceptionally long runs of each of two available options and periods of frequent switching. Neither a satiety-based mechanism nor a random selection process could explain the observed choice behavior. Second, OFC neurons encode important features of the choice behavior. These features include activity selective for exceptionally long runs of a given choice (stay selectivity) as well as activity selective for switches between choices (switch selectivity). These results suggest that OFC neural activity, in addition to encoding subjective values on a long timescale that is sensitive to satiety, also encodes a signal that fluctuates on a shorter timescale and thereby reflects some of the statistically improbable aspects of free-choice behavior.

  17. Power Line Integrity Monitor and Repeater

    2005-09-30

    The Idaho National Laboratory (INL) has developed a power system integrity monitor and repeater that provide real time status of the integrity of the physical structure of power poles and transmission towers. It may be applied to other structures, such as pipelines or cell towers, which have multiple segments that can cover hundreds of miles. Sensors and on-board processing provide indication of tampering or impending damage to the structure with information provided to the centralmore » operations center or supervisory control and data acquisition (SCADA) for mitigative actions. This software runs on a series of small, inexpensive, low power electronic sensor platforms that are mounted on each tower of an electric power transmission or distribution system for the purpose of communicating system integrity to a central location. The software allows each platform to: 1) interface with sensors that monitor tower integrity, 2) record and analyze events, 3) communicate sensor information to other sensor platforms located on adjacent towers or to a central monitoring location, and 4) derive, conserve, and store platform power from the transmission of electric power.« less

  18. Repeating spatial activations in human entorhinal cortex.

    PubMed

    Miller, Jonathan F; Fried, Itzhak; Suthana, Nanthia; Jacobs, Joshua

    2015-04-20

    The ability to remember and navigate spatial environments is critical for everyday life. A primary mechanism by which the brain represents space is through hippocampal place cells, which indicate when an animal is at a particular location. An important issue is understanding how the hippocampal place-cell network represents specific properties of the environment, such as signifying that a particular position is near a doorway or that another position is near the end of a corridor. The entorhinal cortex (EC), as the main input to the hippocampus, may play a key role in coding these properties because it contains neurons that activate at multiple related positions per environment. We examined the diversity of spatial coding across the human medial temporal lobe by recording neuronal activity during virtual navigation of an environment containing four similar paths. Neurosurgical patients performed this task as we recorded from implanted microelectrodes, allowing us to compare the human neuronal representation of space with that of animals. EC neurons activated in a repeating manner across the environment, with individual cells spiking at the same relative location across multiple paths. This finding indicates that EC cells represent non-specific information about location relative to an environment's geometry, unlike hippocampal place cells, which activate at particular random locations. Given that spatial navigation is considered to be a model of how the brain supports non-spatial episodic memory, these findings suggest that EC neuronal activity is used by the hippocampus to represent the properties of different memory episodes.

  19. Repeated intravenous doxapram induces phrenic motor facilitation

    PubMed Central

    Sandhu, MS; Lee, KZ; Gonzalez-Rothi, EJ; Fuller, DD

    2013-01-01

    Doxapram is a respiratory stimulant used to treat hypoventilation. Here we investigated whether doxapram could also trigger respiratory neuroplasticity. Specifically, we hypothesized that intermittent delivery of doxapram at low doses would lead to long-lasting increases (i.e., facilitation) of phrenic motor output in anesthetized, vagotomized, and mechanically-ventilated rats. Doxapram was delivered intravenously in a single bolus (2 or 6 mg/kg) or as a series of 3 injections (2 mg/kg) at 5 min intervals. Control groups received pH-matched saline injections (vehicle) or no treatment (anesthesia time control). Doxapram evoked an immediate increase in phrenic output in all groups, but a persistent increase in burst amplitude only occurred after repeated dosing with 2 mg/kg. At 60 min following the last injection, phrenic burst amplitude was 168±24% of baseline (%BL) in the group receiving 3 injections (P < 0.05 vs. controls), but was 103±8%BL and 112±4%BL in the groups receiving a single dose of 2 or 6 mg/kg, respectively. Following bilateral section of the carotid sinus nerves, the acute phrenic response to doxapram (2 mg/kg) was reduced by 68% suggesting that at low doses the drug was acting primarily via the carotid chemoreceptors. We conclude that intermittent application of doxapram can trigger phrenic neuroplasticity, and this approach might be of use in the context of respiratory rehabilitation following neurologic injury. PMID:24013015

  20. A circular loop of the 16-residue repeating unit in ice nucleation protein.

    PubMed

    Kumaki, Yasuhiro; Kawano, Keiichi; Hikichi, Kunio; Matsumoto, Takeshi; Matsushima, Norio

    2008-06-20

    Ice nucleation protein (INP) from Gram-negative bacteria promotes the freezing of supercooled water. The central domain of INPs with 1034-1567 residues consists of 58-81 tandem repeats with the 16-residue consensus sequence of AxxxSxLTAGYGSTxT. This highly repetitive domain can also be represented by tandem repeats of 8-residues or 48-residues. In order to elucidate the structure of the tandem repeats, NMR measurements were made for three synthetic peptides including QTARKGSDLTTGYGSTS corresponding to a section of the repetitive domains in Xanthomonas campestris INP. One remarkable observation is a long-range NOE between the side chains of Tyr(i) and Ala(i-10) in the 17-residue peptide. Medium-range NOEs between the side chains of Tyr(i) and Leu(i-4), Thr(i-3) or Thr(i-2) were also observed. These side chain-side chain interactions can be ascribed to CH/pi interaction. Structure calculation reveals that the 17-residue peptide forms a circular loop incorporating the 11-residue segment ARKGSDLTTGY.