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Sample records for 8-12 hz activity

  1. [Cerebral hemodynamics in children of 8-12 years old with alterations of the motor activity of central origin].

    PubMed

    Holovchenko, I V; Haĭdaĭ, M I

    2013-01-01

    In children with altered physical activity there is a lack of brain blood supply, which is the most pronounced in the system of the vertebral arteries right hemisphere, and a low volume speed of blood flow in the internal carotid artery and in the system of the vertebral arteries. Children of the main group have a decreased venous outflow from the cavity of the skull, which is accompanied by altered venous circulation in the sinuses of the brain. It is established that in the system of the vertebral arteries a hemispheric asymmetry of growth in the right hemisphere is observed, in contrast to the left hemisphere, indicators of vascular tone of arterial and venous type of small caliber. Children with altered physical activity have higher values of indicators of venous outflow, than the children of the control group, and they have better venous outflow from the carotid system and a slightly worse with vertebro-basilar.

  2. Increased Alpha (8-12 Hz) Activity during Slow Wave Sleep as a Marker for the Transition from Implicit Knowledge to Explicit Insight

    ERIC Educational Resources Information Center

    Yordanova, Juliana; Kolev, Vasil; Wagner, Ullrich; Born, Jan; Verleger, Rolf

    2012-01-01

    The number reduction task (NRT) allows us to study the transition from implicit knowledge of hidden task regularities to explicit insight into these regularities. To identify sleep-associated neurophysiological indicators of this restructuring of knowledge representations, we measured frequency-specific power of EEG while participants slept during…

  3. 15 CFR 8.12 - Hearings.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 1 2011-01-01 2011-01-01 false Hearings. 8.12 Section 8.12 Commerce... Compliance § 8.12 Hearings. (a) Opportunity for hearing. Whenever an opportunity for a hearing is required by... hearing, or (2) advise the recipient or other party that the matter in question has been set down...

  4. 47 CFR 8.12 - Formal complaints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Formal complaints. 8.12 Section 8.12 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRESERVING THE OPEN INTERNET § 8.12 Formal complaints. Any person may file a formal complaint alleging a violation of the rules in this part....

  5. 47 CFR 8.12 - Formal complaints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Formal complaints. 8.12 Section 8.12 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRESERVING THE OPEN INTERNET § 8.12 Formal complaints. Any person may file a formal complaint alleging a violation of the rules in this part....

  6. 47 CFR 8.12 - Formal Complaints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Formal Complaints. 8.12 Section 8.12 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRESERVING THE OPEN INTERNET § 8.12 Formal Complaints. Any person may file a formal complaint alleging a violation of the rules in this part....

  7. 47 CFR 8.12 - Formal complaints.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Formal complaints. 8.12 Section 8.12 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRESERVING THE OPEN INTERNET § 8.12 Formal complaints. Any person may file a formal complaint alleging a violation of the rules in this part....

  8. 22 CFR 8.12 - Financial records.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Financial records. 8.12 Section 8.12 Foreign Relations DEPARTMENT OF STATE GENERAL ADVISORY COMMITTEE MANAGEMENT § 8.12 Financial records. Accurate records will be kept by the responsible committee office of all operating and salary costs of a...

  9. Fast Activity Evoked by Intracranial 50 Hz Electrical Stimulation as a Marker of the Epileptogenic Zone.

    PubMed

    Bellistri, Elisa; Sartori, Ivana; Pelliccia, Veronica; Francione, Stefano; Cardinale, Francesco; de Curtis, Marco; Gnatkovsky, Vadym

    2015-08-01

    Epilepsy is a disease characterized by aberrant connections between brain areas. The altered activity patterns generated by epileptic networks can be analyzed with intracerebral electrodes during pre-surgical stereo-electroencephalographic (EEG) monitoring in patients candidate to epilepsy surgery. The responses to high frequency stimulation (HFS) at 50 Hz performed for diagnostic purposes during SEEG were analyzed with a new algorithm, to evaluate signal parameters that are masked to visual inspection and to define the boundaries of the epileptogenic network. The analysis was focused on 60-80 Hz activity that represented the largest frequency component evoked by HFS. The distribution of HFS-evoked fast activity across all (up to 162) recording contacts allowed to define different clusters of contacts that retrospectively correlated to the epileptogenic zone identified by the clinicians on the basis of traditional visual analysis. The study demonstrates that computer-assisted analysis of HFS-evoked activities may contribute to the definition of the epileptogenic network on intracranial recordings performed in a pre-surgical setting.

  10. 50 Hz sinusoidal magnetic fields do not affect human lymphocyte activation and proliferation in vitro

    NASA Astrophysics Data System (ADS)

    Capri, Miriam; Mesirca, Pietro; Remondini, Daniel; Carosella, Simona; Pasi, Sara; Castellani, Gastone; Franceschi, Claudio; Bersani, Ferdinando

    2004-12-01

    In the last 30 years, an increasing public concern about the possible harmful effects of electromagnetic fields generated by power lines and domestic appliances has pushed the scientific community to search for a correct and comprehensive answer to this problem. In this work the effects of exposure to 50 Hz sinusoidal magnetic fields, with a magnetic flux density of 0.05 mT and 2.5 mT (peak values), were studied on human peripheral blood mononuclear cells (PBMCs) collected from healthy young and elderly donors. Cell activation and proliferation were investigated by using flow cytometry techniques and 3H-TdR incorporation assays, respectively. The results obtained indicated that exposure to the fields altered neither DNA synthesis nor the capacity of lymphocytes to enter the activation phase and progress into the cell cycle. Thus, the conclusions are that two important functional phases of human lymphocytes, such as activation and proliferation, are not affected by exposures to 50 Hz magnetic fields similar to those found under power lines.

  11. Functional Brain Activity Relates to 0-3 and 3-8 Hz Force Oscillations in Essential Tremor.

    PubMed

    Neely, Kristina A; Kurani, Ajay S; Shukla, Priyank; Planetta, Peggy J; Wagle Shukla, Aparna; Goldman, Jennifer G; Corcos, Daniel M; Okun, Michael S; Vaillancourt, David E

    2015-11-01

    It is well-established that during goal-directed motor tasks, patients with essential tremor have increased oscillations in the 0-3 and 3-8 Hz bands. It remains unclear if these increased oscillations relate to activity in specific brain regions. This study used task-based functional magnetic resonance imaging to compare the brain activity associated with oscillations in grip force output between patients with essential tremor, patients with Parkinson's disease who had clinically evident tremor, and healthy controls. The findings demonstrate that patients with essential tremor have increased brain activity in the motor cortex and supplementary motor area compared with controls, and this activity correlated positively with 3-8 Hz force oscillations. Brain activity in cerebellar lobules I-V was reduced in essential tremor compared with controls and correlated negatively with 0-3 Hz force oscillations. Widespread differences in brain activity were observed between essential tremor and Parkinson's disease. Using functional connectivity analyses during the task evidenced reduced cerebellar-cortical functional connectivity in patients with essential tremor compared with controls and Parkinson's disease. This study provides new evidence that in essential tremor 3-8 Hz force oscillations relate to hyperactivity in motor cortex, 0-3 Hz force oscillations relate to the hypoactivity in the cerebellum, and cerebellar-cortical functional connectivity is impaired.

  12. 40 CFR 8.12 - Coordination of reviews from other Parties.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Coordination of reviews from other Parties. 8.12 Section 8.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL ENVIRONMENTAL IMPACT ASSESSMENT OF NONGOVERNMENTAL ACTIVITIES IN ANTARCTICA § 8.12 Coordination of reviews from...

  13. Waste-to-Energy Laboratory. Grades 8-12.

    ERIC Educational Resources Information Center

    HAZWRAP, The Hazardous Waste Remedial Actions Program.

    This brochure contains an activity for grades 8-12 students that focuses on the reuse of waste as an energy source by burning and converting it into energy. For this experiment students construct a calorimeter from simple recyclable material. The calorimeter is used to measure the amount of energy stored in paper and yard waste that could be used…

  14. Reduction of dopamine synaptic activity: degradation of 50-kHz ultrasonic vocalization in rats.

    PubMed

    Ciucci, Michelle R; Ahrens, Allison M; Ma, Sean T; Kane, Jacqueline R; Windham, E Blake; Woodlee, Martin T; Schallert, Timothy

    2009-04-01

    Vocal deficits are prevalent and debilitating in Parkinson's disease. These deficits may be related to the initial pathology of the nigrostriatal dopamine neurons and resulting dopamine depletion, which contributes to dysfunction of fine motor control in multiple functions. Although vocalization in animals and humans may differ in many respects, we evaluated complex (50-kHz) ultrasonic mate calls in 2 rat models of Parkinson's disease, including unilateral infusions of 6-hydroxydopamine to the medial forebrain bundle and peripheral administration of a nonakinesia dose of the dopamine antagonist haloperidol. We examined the effects of these treatments on multiple aspects of the acoustic signal. The number of trill-like (frequency modulated) 50-kHz calls was significantly reduced, and appeared to be replaced by simpler (flat) calls. The bandwidth and maximum intensity of simple and frequency-modulated calls were significantly decreased, but call duration was not. Our findings suggest that the nigrostriatal dopamine pathway is involved to some extent in fine sensorimotor function that includes USV production and complexity.

  15. The origin of the 900 Hz spectral peak in spontaneous and sound-evoked round-window electrical activity.

    PubMed

    McMahon, Catherine M; Patuzzi, Robert B

    2002-11-01

    We have monitored the spectrum of the (spontaneous) neural noise at the round window (RW) and on the surface of the antero-ventral cochlear nucleus (CN) and the dorsal CN (DCN) of anaesthetised guinea pigs. We have also obtained the average gross extracellular waveform evoked by 20 kHz tone-bursts (0.25 ms and 25 ms) at each of these recording sites, and calculated the spectrum of the average waveforms (SAW). With these tone-bursts, only a small population of neurones in the extreme basal turn of the cochlea near the RW electrode responds, presumably with only a single action potential for each 0.25 ms tone-burst. The RW waveforms recorded between 20 dB and 60 dB SPL were very similar, and are therefore presumably a simple estimate of the shape of the contribution of the firing of a single neurone to the gross RW signal (the unitary potential or UP). In normal animals, the SNN and the SAW were remarkably similar, with peaks at 900 Hz and at 2400 Hz, suggesting that they are not due to neural synchronisation (as suggested previously by others), but are due to an oscillatory waveform produced by each single fibre action potential. Abolition of all spike activity by RW tetrodotoxin left a waveform with only a summating potential and a dendritic potential, and no 900 Hz peak in the SAW or SNN, indicating that the spectral peak is due to neural spiking only. Abolition of the CN contribution to the RW waveforms by CN application of lignocaine or sectioning of the cochlear nerve at the internal meatus (by focal aspiration of the DCN and underlying cochlear nerve) showed that the 900 Hz peak was not simply due to the addition of a delayed and inverted CN contribution: mathematical modelling shows that this would produce a broad spectral peak at about 1200 Hz. Moreover, the 900 Hz spectral peak remains after complete abolition of the CN contribution, although reduced in amplitude. This residual 900 Hz peak can be traced to an oscillation in the gross waveform due to the

  16. In vitro Neurons in Mammalian Cortical Layer 4 Exhibit Intrinsic Oscillatory Activity in the 10- to 50-Hz Frequency Range

    NASA Astrophysics Data System (ADS)

    Llinas, Rodolfo R.; Grace, Anthony A.; Yarom, Yosef

    1991-02-01

    We report here the presence of fast subthreshold oscillatory potentials recorded in vitro from neurons within layer 4 of the guinea pig frontal cortex. Two types of oscillatory neurons were recorded: (i) One type exhibited subthreshold oscillations whose frequency increased with membrane depolarization and encompassed a range of 10-45 Hz. Action potentials in this type of neuron demonstrated clear after-hyperpolarizations. (ii) The second type of neuron was characterized by narrow-frequency oscillations near 35-50 Hz. These oscillations often outlasted the initiating depolarizing stimulus. No calcium component could be identified in their action potential. In both types of cell the subthreshold oscillations were tetrodotoxin-sensitive, indicating that the depolarizing phase of the oscillation was generated by a voltage-dependent sodium conductance. The initial depolarizing phase was followed by a potassium conductance responsible for the falling phase of the oscillatory wave. In both types of cell, the subthreshold oscillation could trigger spikes at the oscillatory frequency, if the membrane was sufficiently depolarized. Combining intracellular recordings with Lucifer yellow staining showed that the narrow-frequency oscillatory activity was produced by a sparsely spinous interneuron located in layer 4 of the cortex. This neuron has extensive local axonal collaterals that ramify in layers 3 and 4 such that they may contribute to the columnar synchronization of activity in the 40- to 50-Hz range. Cortical activity in this frequency range has been proposed as the basis for the "conjunctive properties" of central nervous system networks.

  17. Circadian locomotor activity of Musca flies: Recording method and effects of 10 Hz square-wave electric fields

    SciTech Connect

    Engelmann, W.; Hellrung, W.; Johnsson, A.

    1996-05-01

    Musca domestica flies that were exposed to a uniform vertical 10 Hz electric square-wave field of 1 kVm{sup {minus}1} changed the period length of their circadian locomotor activity rhythm. Under constant conditions, the clock of short-period flies was slowed down by the field, whereas the clock of long-period flies either was affected only scarcely (experiments at about 19 C) or ran faster (experiments at 25 C). It the field was applied for only 12 h daily, then 30--40% of the flies were synchronized. Thus, the field could function as a weak Zeitgeber (synchronizer). If the field was increased to 10 kVm{sup {minus}1}, then 50--70% of the flies were synchronized. Flies avoided becoming active around the onset of the 12 h period of exposure to a 10 Hz field. The results of these experiments are discussed with respect to similar experiments by Wever on the effects of exposure to a 10 Hz field on the circadian system of man.

  18. Circadian locomotor activity of Musca flies: recording method and effects of 10 Hz square-wave electric fields.

    PubMed

    Engelmann, W; Hellrung, W; Johnsson, A

    1996-01-01

    Musca domestica flies that were exposed to a uniform vertical 10 Hz electric square-wave field of 1 kVm(-1) changed the period length of their circadian locomotor activity rhythm. Under constant conditions, the clock of short-period flies was slowed down by the field, whereas the clock of long-period flies either was affected only scarcely (experiments at about 19 degrees C) or ran faster (experiments at 25 degrees C). If the field was applied for only 12 h daily, then 30-40 percent of the flies were synchronized. Thus, the field could function as a weak "Zeitgeber" (synchronizer). If the field was increased to 10 kVm(-1), then 50-70 percent of the flies were synchronized. Flies avoided becoming active around the onset of the 12 h period of exposure to a 10 Hz field. The results of these experiments are discussed with respect to similar experiments by Wever on the effects of exposure to a 10 Hz field on the circadian system of man. PMID:9139632

  19. D1-dependent 4 Hz oscillations and ramping activity in rodent medial frontal cortex during interval timing.

    PubMed

    Parker, Krystal L; Chen, Kuan-Hua; Kingyon, Johnathan R; Cavanagh, James F; Narayanan, Nandakumar S

    2014-12-10

    Organizing behavior in time is a fundamental process that is highly conserved across species. Here we study the neural basis of timing processes. First, we found that rodents had a burst of stimulus-triggered 4 Hz oscillations in the medial frontal cortex (MFC) during interval timing tasks. Second, rodents with focally disrupted MFC D1 dopamine receptor (D1DR) signaling had impaired interval timing performance and weaker stimulus-triggered oscillations. Prior work has demonstrated that MFC neurons ramp during interval timing, suggesting that they underlie temporal integration. We found that MFC D1DR blockade strongly attenuated ramping activity of MFC neurons that correlated with behavior. These macro- and micro-level phenomena were linked, as we observed that MFC neurons with strong ramping activity tended to be coherent with stimulus-triggered 4 Hz oscillations, and this relationship was diminished with MFC D1DR blockade. These data provide evidence demonstrating how D1DR signaling controls the temporal organization of mammalian behavior. PMID:25505330

  20. Effects of intermittent 60-Hz high voltage electric fields on metabolism, activity, and temperature in mice

    SciTech Connect

    Rosenbergy, R.S; Duffy, P.H.; Sacher, G.A.

    1981-01-01

    Transient effects of 100-kV/m extremely low frequency electric fields were studied in the white footed deermouse, Peromyscus leucopus. Gross motor activity, carbon dioxide production, oxygen consumption, and core body temperature were monitored before, during, and after intermittent field exposures (four hour-long exposures, at one-hour intervals). Thirty-four mice were exposed in cages with plastic floors floating above ground potential, and 21 mice were exposed in cages with grounded metal floor plates. The first field exposure produced an immediate, transient increase of activity and gas measures during the inactive phase of the circadian cycle. All measures returned to baseline levels before the second exposure and were not significantly changed throughout the remainder of the exposures. The rapid habituation of field-induced arousal suggests that significant metabolic changes will not be measured in experiments in which the interval between exposure and measurement is greater than two hours.

  1. Effects of a 60 Hz Magnetic Field Exposure Up to 3000 μT on Human Brain Activation as Measured by Functional Magnetic Resonance Imaging

    PubMed Central

    Legros, Alexandre; Modolo, Julien; Brown, Samantha; Roberston, John; Thomas, Alex W.

    2015-01-01

    Several aspects of the human nervous system and associated motor and cognitive processes have been reported to be modulated by extremely low-frequency (ELF, < 300 Hz) time-varying Magnetic Fields (MF). Due do their worldwide prevalence; power-line frequencies (60 Hz in North America) are of particular interest. Despite intense research efforts over the last few decades, the potential effects of 60 Hz MF still need to be elucidated, and the underlying mechanisms to be understood. In this study, we have used functional Magnetic Resonance Imaging (fMRI) to characterize potential changes in functional brain activation following human exposure to a 60 Hz MF through motor and cognitive tasks. First, pilot results acquired in a first set of subjects (N=9) were used to demonstrate the technical feasibility of using fMRI to detect subtle changes in functional brain activation with 60 Hz MF exposure at 1800 μT. Second, a full study involving a larger cohort of subjects tested brain activation during 1) a finger tapping task (N=20), and 2) a mental rotation task (N=21); before and after a one-hour, 60 Hz, 3000 μT MF exposure. The results indicate significant changes in task-induced functional brain activation as a consequence of MF exposure. However, no impact on task performance was found. These results illustrate the potential of using fMRI to identify MF-induced changes in functional brain activation, suggesting that a one-hour 60 Hz, 3000 μT MF exposure can modulate activity in specific brain regions after the end of the exposure period (i.e., residual effects). We discuss the possibility that MF exposure at 60 Hz, 3000 μT may be capable of modulating cortical excitability via a modulation of synaptic plasticity processes. PMID:26214312

  2. 42 CFR 8.12 - Federal opioid treatment standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Federal opioid treatment standards. 8.12 Section 8... CERTIFICATION OF OPIOID TREATMENT PROGRAMS Certification and Treatment Standards § 8.12 Federal opioid treatment standards. (a) General. OTPs must provide treatment in accordance with the standards in this section...

  3. 42 CFR 8.12 - Federal opioid treatment standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Federal opioid treatment standards. 8.12 Section 8... CERTIFICATION OF OPIOID TREATMENT PROGRAMS Certification and Treatment Standards § 8.12 Federal opioid treatment standards. (a) General. OTPs must provide treatment in accordance with the standards in this section...

  4. 42 CFR 8.12 - Federal opioid treatment standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Federal opioid treatment standards. 8.12 Section 8... CERTIFICATION OF OPIOID TREATMENT PROGRAMS Certification and Treatment Standards § 8.12 Federal opioid treatment standards. (a) General. OTPs must provide treatment in accordance with the standards in this section...

  5. Slow modulations of high-frequency activity (40-140-Hz) discriminate preictal changes in human focal epilepsy.

    PubMed

    Alvarado-Rojas, C; Valderrama, M; Fouad-Ahmed, A; Feldwisch-Drentrup, H; Ihle, M; Teixeira, C A; Sales, F; Schulze-Bonhage, A; Adam, C; Dourado, A; Charpier, S; Navarro, V; Le Van Quyen, M

    2014-01-01

    Recent evidence suggests that some seizures are preceded by preictal changes that start from minutes to hours before an ictal event. Nevertheless an adequate statistical evaluation in a large database of continuous multiday recordings is still missing. Here, we investigated the existence of preictal changes in long-term intracranial recordings from 53 patients with intractable partial epilepsy (in total 531 days and 558 clinical seizures). We describe a measure of brain excitability based on the slow modulation of high-frequency gamma activities (40-140 Hz) in ensembles of intracranial contacts. In prospective tests, we found that this index identified preictal changes at levels above chance in 13.2% of the patients (7/53), suggesting that results may be significant for the whole group (p < 0.05). These results provide a demonstration that preictal states can be detected prospectively from EEG data. They advance understanding of the network dynamics leading to seizure and may help develop novel seizure prediction algorithms. PMID:24686330

  6. 30 Hz-linewidth, diode-laser-pumped, Nd:GGG nonplanar ring oscillators by active frequency stabilisation

    NASA Technical Reports Server (NTRS)

    Day, T.; Nilsson, A. C.; Fejer, M. M.; Farinas, A. D.; Gustafson, E. K.

    1989-01-01

    A heterodyne linewidth of less than 30 Hz for the beatnote between the outputs of two 282 THz Nd:GGG nonplanar ring oscillators (NPROs) is reported. The lasers were independently locked to adjacent axial modes of a high-finesse interferometer. The remnant frequency noise appears to be dominated by free spectral range fluctuations in the reference interferometer rather than by residual laser noise.

  7. Task failure during standing heel raises is associated with increased power from 13 to 50 Hz in the activation of triceps surae

    PubMed Central

    Pereira, Rafael; Schettino, Ludmila; Machado, Marco; Victor da Silva, Pierre Augusto; Neto, Osmar Pinto

    2010-01-01

    The goal of this paper was to investigate the amplitude and sub-100 Hz frequency content of surface electromyography (EMG) signals obtained from agonist, antagonist and synergist muscles during a heel-raise task sustained to failure. Twenty-two healthy adults, 14 men and 8 women participated in the study. Surface EMG data from the raising and lowering phases of the movement were studied in the time (EMG amplitude) and frequency (wavelet transform) domains. For the raising phase, we found a significant increase in the EMG amplitude of all muscles studied throughout the task (P < 0.02); however, for the lowering phase, we found a decrease in overall muscle activation for the medial gastrocnemius and tibialis anterior. Additionally, we found higher 13–30 and 30–50 Hz normalized power during the raising phase for the triceps surae prior to task failure and at task failure compared with the beginning and midway of the task (P < 0.05); during the lowering phase, however, we found higher normalized power from 30 to 50 Hz for the triceps surae (P < 0.01) and higher 13–30 Hz normalized power for the tibialis anterior (P < 0.01) at task failure compared with the beginning and midway of the task. Finally, we showed that a dynamic task performed until failure can induce different activation strategies for agonist, antagonist and synergist muscles, and that the frequency content below 100 Hz contains useful information about the neural activation of these muscles in relation to task failure that is not evident from the EMG amplitude. PMID:20455068

  8. 41 CFR 51-8.12 - Fee schedule.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... MATERIALS § 51-8.12 Fee schedule. (a) This schedule sets forth fees to be charged for processing requests... manual search time, or the first two minutes of computer search time, except on requests seeking... microfilm, audio-visual materials, or machine-readable documentation (i.e., magnetic tape or disk) shall...

  9. Effect of 60 Hz electromagnetic fields on the activity of hsp70 promoter: an in vivo study

    PubMed Central

    Rodríguez-De la Fuente, Abraham O.; Alcocer-González, Juan M.; Heredia-Rojas, J. Antonio; Rodríguez-Padilla, Cristina; Rodríguez-Flores, Laura E.; Santoyo-Stephano, Martha A.; Castañeda-Garza, Esperanza; Taméz-Guerra, Reyes S.

    2012-01-01

    Exposure to EMFs (electromagnetic fields) results in a number of important biological changes, including modification of genetic expression. We have investigated the effect of 60 Hz sinusoidal EMFs at a magnetic flux density of 80 μT on the expression of the luciferase gene contained in a plasmid labelled as pEMF (EMF plasmid). This gene construct contains the specific sequences for the induction of hsp70 (heat-shock protein 70) expression by EMFs, as well as the reporter for the luciferase gene. The pEMF vector was electrotransferred into quadriceps muscles of BALB/c mice that were later exposed to EMFs. Increased luciferase expression was observed in mice exposed to EMFs 2 h daily for 7 days compared with controls (P<0.05). These data along with other reports in the literature suggest that EMFs can have far-reaching effects on the genome. PMID:23124775

  10. Effect of 60 Hz electromagnetic fields on the activity of hsp70 promoter: an in vitro study.

    PubMed

    Rodríguez de la Fuente, Abraham O; Alcocer-González, Juan M; Antonio Heredia-Rojas, J; Balderas-Candanosa, Isaías; Rodríguez-Flores, Laura E; Rodríguez-Padilla, Cristina; Taméz-Guerra, Reyes S

    2009-03-01

    We have evaluated the effect of 60 Hz sinusoidal magnetic fields (MF) at 8 and 8 microT on expression of the luciferase gene contained in a gene construct labelled as Electromagnetic Field-plasmid (pEMF). The vector included the hsp70 promotor containing the 3 nCTCTn sequences previously described for the induction of hsp70 expression by magnetic fields, as well as the reporter of the luciferase gene. We also replicated the study of Lin et al. [Lin H, Blank M, Rossol-Haseroth K, Goodman R. Regulating genes with electromagnetic response elements. J Cell Biochem 2001;81(1):143-48]. The pEMF plasmid was transfected into HeLa and BMK16 cell lines that were later exposed to either MF or thermal shock (TS). An increased luciferase expression was found in both the cells exposed to MF and TS compared with their control groups (P < 0.05). Furthermore, the combined effect of MF and TS was also analyzed. A synergistic effect between two factors was observed for this co-exposure condition in terms of luciferase gene expression.

  11. Medial frontal ∼4-Hz activity in humans and rodents is attenuated in PD patients and in rodents with cortical dopamine depletion

    PubMed Central

    Parker, Krystal L.; Chen, Kuan-Hua; Kingyon, Johnathan R.; Cavanagh, James F.

    2015-01-01

    The temporal control of action is a highly conserved and critical mammalian behavior. Here, we investigate the neuronal basis of this process using an interval timing task. In rats and humans, instructional timing cues triggered spectral power across delta and theta bands (2–6 Hz) from the medial frontal cortex (MFC). Humans and rodents with dysfunctional dopamine have impaired interval timing, and we found that both humans with Parkinson's disease (PD) and rodents with local MFC dopamine depletion had attenuated delta and theta activity. In rodents, spectral activity in this range could functionally couple single MFC neurons involved in temporal processing. Without MFC dopamine, these neurons had less functional coupling with delta/theta activity and less temporal processing. Finally, in humans this 2- to 6-Hz activity was correlated with executive function in matched controls but not in PD patients. Collectively, these findings suggest that cue-evoked low-frequency rhythms could be a clinically important biomarker of PD that is translatable to rodent models, facilitating mechanistic inquiry and the development of neurophysiological biomarkers for human disease. PMID:26133799

  12. 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.

  13. Bidirectional modulation of hippocampal gamma (20-80 Hz) frequency activity in vitro via alpha(α)- and beta(β)-adrenergic receptors (AR).

    PubMed

    Haggerty, D C; Glykos, V; Adams, N E; Lebeau, F E N

    2013-12-01

    Noradrenaline (NA) in the hippocampus plays an important role in memory function and has been shown to modulate different forms of synaptic plasticity. Oscillations in the gamma frequency (20-80 Hz) band in the hippocampus have also been proposed to play an important role in memory functions and, evidence from both in vitro and in vivo studies, has suggested this activity can be modulated by NA. However, the role of different NA receptor subtypes in the modulation of gamma frequency activity has not been fully elucidated. We have found that NA (30 μM) exerts a bidirectional control on the magnitude of kainate-evoked (50-200 nM) gamma frequency oscillations in the cornu Ammonis (CA3) region of the rat hippocampus in vitro via activation of different receptor subtypes. Activation of alpha-adrenergic receptors (α-AR) reduced the power of the gamma frequency oscillation. In contrast, activation of beta-adrenergic receptors (β-AR) caused an increase in the power of the gamma frequency oscillations. Using specific agonists and antagonists of AR receptor subtypes we demonstrated that these effects are mediated specifically via α1A-AR and β1-AR subtypes. NA activated both receptor subtypes, but the α1A-AR-mediated effect predominated, resulting in a reversible suppression of gamma frequency activity. These results suggest that NA is able to differentially modulate on-going gamma frequency oscillatory activity that could result in either increased or decreased information flow through the hippocampus.

  14. Activity of Tri-N-Butyl Tin maleate in carpets against Staphylococcus aureus and Aspergillus niger, verified through two methodologies: Inhibition Halo (HZ) and Inhibition Surface (Print).

    PubMed

    Uehara, Satiko; Franzolin, Marcia Regina; Viani, Flávio César; Chiesa, Soledad; França, Aricelma Pinheiro; Paula, Claudete Rodrigues

    2008-01-01

    The aim of the present study was to verify the activity of the Tri-N-Butyl Tin maleate compound against Staphylococcus aureus and Aspergillus niger, after its industrial application in 40 samples of carpets of different materials (polypropylene, polyester, polyamide and wool). The qualitative assays were performed through two methodologies: Inhibition Halo (HZ) and Inhibition of Surface (Print). The carpet with the product inhibited 100% of bacterial (Staphylococcus aureus) and fungi (Aspergillus niger) growth, under the conditions of this study. The microbial inhibition was higher in upper portion of carpets. The methodologies employed appear to be adequate to test the bactericide and fungicide activities of the Tri-N-Butyl Tin maleate. The print methodology confirmed the results obtained by the inhibition zone assay. Further studies using the same methodologies are needed to confirm our results.

  15. Effect of 60 Hz magnetic fields on the activation of hsp70 promoter in cultured INER-37 and RMA E7 cells.

    PubMed

    Heredia-Rojas, J Antonio; Rodríguez de la Fuente, Abraham Octavio; Alcocer González, Juan Manuel; Rodríguez-Flores, Laura E; Rodríguez-Padilla, Cristina; Santoyo-Stephano, Martha A; Castañeda-Garza, Esperanza; Taméz-Guerra, Reyes S

    2010-10-01

    It has been reported that 50-60 Hz magnetic fields (MF) with flux densities ranging from microtesla to millitesla are able to induce heat shock factor or heat shock proteins in various cells. In this study, we investigated the effect of 60 Hz sinusoidal MF at 8 and 80 μT on the expression of the luciferase gene contained in a plasmid labeled as electromagnetic field-plasmid (pEMF). This gene construct contains the specific sequences previously described for the induction of hsp70 expression by MF, as well as the reporter for the luciferase gene. The pEMF vector was transfected into INER-37 and RMA E7 cell lines that were later exposed to either MF or thermal shock (TS). Cells that received the MF or TS treatments and their controls were processed according to the luciferase assay system for evaluate luciferase activity. An increased luciferase gene expression was observed in INER-37 cells exposed to MF and TS compared with controls (p < 0.05), but MF exposure had no effect on the RMA E7 cell line.

  16. Extension of non-invasive EEG into the kHz range for evoked thalamocortical activity by means of very low noise amplifiers.

    PubMed

    Scheer, H J; Fedele, T; Curio, G; Burghoff, M

    2011-12-01

    Ultrafast electroencephalographic signals, having frequencies above 500 Hz, can be observed in somatosensory evoked potential measurements. Usually, these recordings have a poor signal-to-noise ratio (SNR) because weak signals are overlaid by intrinsic noise of much higher amplitude like that generated by biological sources and the amplifier. As an example, recordings at the scalp taken during electrical stimulation of the median nerve show a 600 Hz burst with submicro-volt amplitudes which can be extracted from noise by the use of massive averaging and digital signal processing only. We have investigated this signal by means of a very low noise amplifier made in-house (minimal voltage noise 2.7 nV Hz(-1/2), FET inputs). We examined how the SNR of the data is altered by the bandwidth and the use of amplifiers with different intrinsic amplifier noise levels of 12 and 4.8 nV Hz(-1/2), respectively. By analyzing different frequency contributions of the signal, we found an extremely weak 1 kHz component superimposed onto the well-known 600 Hz burst. Previously such high-frequency electroencephalogram responses around 1 kHz have only been observed by deep brain electrodes implanted for tremor therapy of Parkinson patients. For the non-invasive measurement of such signals, we recommend that amplifier noise should not exceed 4 nV Hz(-1/2).

  17. 10 Hz flicker improves recognition memory in older people

    PubMed Central

    Williams, Jonathan; Ramaswamy, Deepa; Oulhaj, Abderrahim

    2006-01-01

    Background 10 Hz electroencephalographic (EEG) alpha rhythms correlate with memory performance. Alpha and memory decline in older people. We wished to test if alpha-like EEG activity contributes to memory formation. Flicker can elicit alpha-like EEG activity. We tested if alpha-frequency flicker enhances memory in older people. Pariticpants aged 67–92 identified short words that followed 1 s of flicker at 9.0 Hz, 9.5 Hz, 10.0 Hz, 10.2 Hz, 10.5 Hz, 11.0 Hz, 11.5 Hz or 500 Hz. A few minutes later, we tested participants' recognition of the words (without flicker). Results Flicker frequencies close to 10 Hz (9.5–11.0 Hz) facilitated the identification of the test words in older participants. The same flicker frequencies increased recognition of the words more than other frequencies (9.0 Hz, 11.5 Hz and 500 Hz), irrespective of age. Conclusion The frequency-specificity of flicker's effects in our participants paralleled the power spectrum of EEG alpha in the general population. This indicates that alpha-like EEG activity may subserve memory processes. Flicker may be able to help memory problems in older people. PMID:16515710

  18. Project EAGLE (Early Academic Gifted Learning Experience): A Program for Gifted and Talented Students (Grades K-3)--Kindergarten Activity Booklets: Xanthus; Zhack; and Activity Pages H-Z.

    ERIC Educational Resources Information Center

    Merkoski, Kay

    Three activity booklets are presented for implementing Project EAGLE, an enrichment program for gifted and talented kindergarten children. The first activity booklet contains a poem by J. D. Evans titled "In Search of the Xanthus," which describes the search for an imaginary beast that leaves an "X" on the spot where it used to be. The second…

  19. A novel method for recording neuronal depolarization with recording at 125-825 Hz: implications for imaging fast neural activity in the brain with electrical impedance tomography.

    PubMed

    Oh, T; Gilad, O; Ghosh, A; Schuettler, M; Holder, D S

    2011-05-01

    Electrical impedance tomography (EIT) is a recently developed medical imaging method which has the potential to produce images of fast neuronal depolarization in the brain. Previous modelling suggested that applied current needed to be below 100 Hz but the signal-to-noise ratio (SNR) recorded with scalp electrodes during evoked responses was too low to permit imaging. A novel method in which contemporaneous evoked potentials are subtracted is presented with current applied at 225 Hz to cerebral cortex during evoked activity; although the signal is smaller than at DC by about 10×, the principal noise from the EEG is reduced by about 1000×, resulting in an improved SNR. It was validated with recording of compound action potentials in crab walking leg nerve where peak changes of -0.2% at 125 and 175 Hz tallied with biophysical modelling. In recording from rat cerebral cortex during somatosensory evoked responses, peak impedance decreases of -0.07 ± 0.006% (mean ± SE) with a SNR of >50 could be recorded at 225 Hz. This method provides a reproducible and artefact free means for recording resistance changes during neuronal activity which could form the basis for imaging fast neural activity in the brain.

  20. Active frequency stabilization of a 1.062-micron, Nd:GGG, diode-laser-pumped nonplanar ring oscillator to less than 3 Hz of relative linewidth

    NASA Technical Reports Server (NTRS)

    Day, T.; Gustafson, E. K.; Byer, R. L.

    1990-01-01

    Results are presented on the frequency stabilization of two diode-laser-pumped ring lasers that are independently locked to the same high-finesse interferometer. The relative frequency stability is measured by locking the lasers one free spectral range apart and observing the heterodyne beat note. The resultant beat note width of 2.9 Hz is consistent with the theoretical system noise-limited linewidth and is approximately 20 times that expected for shot-noise-limited performance.

  1. 7 CFR 319.8-12 - From the West Coast of Mexico.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false From the West Coast of Mexico. 319.8-12 Section 319.8... Conditions for the Entry of Cotton and Covers from Mexico § 319.8-12 From the West Coast of Mexico. Contingent upon continued freedom of the West Coast of Mexico and of Northwest Mexico from infestations...

  2. 7 CFR 319.8-12 - From the West Coast of Mexico.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false From the West Coast of Mexico. 319.8-12 Section 319.8... Conditions for the Entry of Cotton and Covers from Mexico § 319.8-12 From the West Coast of Mexico. Contingent upon continued freedom of the West Coast of Mexico and of Northwest Mexico from infestations...

  3. 7 CFR 319.8-12 - From the West Coast of Mexico.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false From the West Coast of Mexico. 319.8-12 Section 319.8... Conditions for the Entry of Cotton and Covers from Mexico § 319.8-12 From the West Coast of Mexico. Contingent upon continued freedom of the West Coast of Mexico and of Northwest Mexico from infestations...

  4. 7 CFR 319.8-12 - From the West Coast of Mexico.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false From the West Coast of Mexico. 319.8-12 Section 319.8... Conditions for the Entry of Cotton and Covers from Mexico § 319.8-12 From the West Coast of Mexico. Contingent upon continued freedom of the West Coast of Mexico and of Northwest Mexico from infestations...

  5. 7 CFR 319.8-12 - From the West Coast of Mexico.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false From the West Coast of Mexico. 319.8-12 Section 319.8... Conditions for the Entry of Cotton and Covers from Mexico § 319.8-12 From the West Coast of Mexico. Contingent upon continued freedom of the West Coast of Mexico and of Northwest Mexico from infestations...

  6. Modification of the ultrasound induced activity by the presence of an electrode in a sonoreactor working at two low frequencies (20 and 40 kHz). Part I: Active zone visualization by laser tomography.

    PubMed

    Mandroyan, A; Viennet, R; Bailly, Y; Doche, M-L; Hihn, J-Y

    2009-01-01

    Sonoelectrochemical experiments differ from sonochemical ones by the introduction of electrodes in the sonicated reaction vessel. The aim of the study is to characterize the changes of the ultrasonic activity induced by the presence of an electrode located in front of the transducer. The scope of our investigations concerns two low frequencies vibration modes: 20 and 40 kHz. For this purpose, two laser visualization techniques have been used. The first part of the study, described in the present paper (part I), deals with the laser tomography technique which provides an accurate picture of the reactor actives zones, related to numerous cavitation events. For each frequency, two parameters were studied: the electrical power supplied to the transducer and the electrode transducer distance. At both frequencies, without electrode, we can observe distinct zones corresponding to cavitation production and stationary waves establishment. When increasing the input power, bubble clouds tend to form a unique cloud near the transducer. In presence of the electrode, bubble cavitation clouds are largely influenced by the obstacle. The second part of the paper (part II) will describe the Particle Image Velocimetry (P.I.V.) technique which allows to measure the velocity vector field in the fluid portion between the horn and the electrode.

  7. Intracerebroventricular injection of mu- and delta-opiate receptor antagonists block 60 Hz magnetic field-induced decreases in cholinergic activity in the frontal cortex and hippocampus of the rat.

    PubMed

    Lai, H; Carino, M

    1998-01-01

    In previous research, we have found that acute exposure to a 60 Hz magnetic field decreased cholinergic activity in the frontal cortex and hippocampus of the rat as measured by sodium-dependent high-affinity choline uptake activity. We concluded that the effect was mediated by endogenous opioids inside the brain because it could be blocked by pretreatment of rats before magnetic field exposure with the opiate antagonist naltrexone, but not by the peripheral antagonist naloxone methiodide. In the present study, the involvement of opiate receptor subtypes was investigated. Rats were pretreated by intracerebroventricular injection of the mu-opiate receptor antagonist, beta-funaltrexamine, or the delta-opiate receptor antagonist, naltrindole, before exposure to a 60 Hz magnetic field (2 mT, 1 hour). It was found that the effects of magnetic field on high-affinity choline uptake in the frontal cortex and hippocampus were blocked by the drug treatments. These data indicate that both mu- and delta-opiate receptors in the brain are involved in the magnetic field-induced decreases in cholinergic activity in the frontal cortex and hippocampus of the rat.

  8. Lytic efficacy of apoli protein E2 (ApoE2) and recombinant tissue plasminogen activator (rt-PA) treatment with 120 kHz ultrasound in an in-vitro human clot model

    NASA Astrophysics Data System (ADS)

    Meunier, Jason M.; Cheng, Jason Y.; Clark, Joseph F.; Shaw, George J.

    2005-04-01

    Currently, the only FDA approved therapy for acute ischemic stroke is recombinant tissue plasminogen activator (rt-PA). However rt-PA has substantial side effects such as hemorrhage. This has led to interest in other potential therapies. For example, ultrasound (US) increases the lytic efficacy of rt-PA. Also, apolipoprotein E2 (ApoE2) increases rt-PA activity. This suggests combining US, ApoE2 and rt-PA to improve thrombolysis, but the efficacy is not known. Here, the lytic efficacy of apoE2, rt-PA and 120 kHz US is measured in a human clot model. Whole blood was obtained from volunteers, after local institutional approval. Clots were formed in 1.7 mm micropipettes, and placed in a water tank that allowed microscopic video imaging during US and thrombolytic exposure. Clots were treated with rt-PA ([rt-PA]=3.15 μg/ml), rt-PA and apoE2 ([apoE2]=9.8 μg/ml), or rt-PA, apoE2 and 120 kHz US (0.35 MPa, PRF=1667 Hz, 80% duty cycle) for 15 min at 37°C in human plasma. Clot lysis was visually recorded and the lysis depth (LD) determined from these data using an image analysis algorithm. LD was linear with time for all treatments (R2>=0.81), allowing the determination of a lytic rate (LR). LR was found to be 0.35+/-0.03, 1.55+/-0.11, and 0.75+/-0.04 μm/min for the rt-PA, rt-PA and apoE2, and US treated groups respectively. The thrombolytic efficacy of rt-PA is enhanced by ApoE2. The interaction of 120 kHz with apoE2 and rt-PA showed a reduced lytic efficacy compared with rt-PA and apoE2 treatment alone. It is possible that US interferes with the ApoE2-mediated activation of rt-PA.

  9. Proceedings of the Fourth International Seminar on Special Education (Cork, Ireland, September 8-12, 1969).

    ERIC Educational Resources Information Center

    McHugh, M. F., Ed.

    Proceedings of the Fourth International Seminar on Special Education (Cork, Ireland, September 8-12, 1969) contain papers relating to the following themes: special education personnel, identification of the handicapped, general aspects of early education, special education methods, early education programs for the mentally handicapped, and early…

  10. Child Labor Is Not Cheap: A Unit for Grades 8-12 and Adults.

    ERIC Educational Resources Information Center

    Sanders, Amy; Sommers, Meredith, Ed.

    This 3-lesson unit of study for grades 8-12 and adults considers the 250 million children who spend most of their day on the job, despite efforts to regulate or eliminate the practice of child labor. The unit focuses primarily on export-oriented businesses in the Americas. This focus serves as a starting point to understanding other forms of…

  11. Epilepsy provoked by television and video games: safety of 100-Hz screens.

    PubMed

    Ricci, S; Vigevano, F; Manfredi, M; Kasteleijn-Nolst Trenité, D G

    1998-03-01

    Television (TV) and video games (VG) can provoke seizures in patients with photosensitive epilepsies. Flicker frequency is the most important factor in screen activation. We tested conventional 50-Hz versus 100-Hz monitors during TV viewing and VG playing in 30 photosensitive subjects, 23 of whom had a history of TV or VG seizures or both. Fifteen subjects' discharges were activated by 50-Hz TV; 17 by 50-Hz VG; and one by a 100-Hz screen. Thus, 100-Hz screens protect against screen activation. PMID:9521278

  12. Epilepsy provoked by television and video games: safety of 100-Hz screens.

    PubMed

    Ricci, S; Vigevano, F; Manfredi, M; Kasteleijn-Nolst Trenité, D G

    1998-03-01

    Television (TV) and video games (VG) can provoke seizures in patients with photosensitive epilepsies. Flicker frequency is the most important factor in screen activation. We tested conventional 50-Hz versus 100-Hz monitors during TV viewing and VG playing in 30 photosensitive subjects, 23 of whom had a history of TV or VG seizures or both. Fifteen subjects' discharges were activated by 50-Hz TV; 17 by 50-Hz VG; and one by a 100-Hz screen. Thus, 100-Hz screens protect against screen activation.

  13. Local Optogenetic Induction of Fast (20–40 Hz) Pyramidal-Interneuron Network Oscillations in the In Vitro and In Vivo CA1 Hippocampus: Modulation by CRF and Enforcement of Perirhinal Theta Activity

    PubMed Central

    Dine, Julien; Genewsky, Andreas; Hladky, Florian; Wotjak, Carsten T.; Deussing, Jan M.; Zieglgänsberger, Walter; Chen, Alon; Eder, Matthias

    2016-01-01

    The neurophysiological processes that can cause theta-to-gamma frequency range (4–80 Hz) network oscillations in the rhinal cortical-hippocampal system and the potential connectivity-based interactions of such forebrain rhythms are a topic of intensive investigation. Here, using selective Channelrhodopsin-2 (ChR2) expression in mouse forebrain glutamatergic cells, we were able to locally, temporally precisely, and reliably induce fast (20–40 Hz) field potential oscillations in hippocampal area CA1 in vitro (at 25°C) and in vivo (i.e., slightly anesthetized NEX-Cre-ChR2 mice). As revealed by pharmacological analyses and patch-clamp recordings from pyramidal cells and GABAergic interneurons in vitro, these light-triggered oscillations can exclusively arise from sustained suprathreshold depolarization (~200 ms or longer) and feedback inhibition of CA1 pyramidal neurons, as being mandatory for prototypic pyramidal-interneuron network (P-I) oscillations. Consistently, the oscillations comprised rhythmically occurring population spikes (generated by pyramidal cells) and their frequency increased with increasing spectral power. We further demonstrate that the optogenetically driven CA1 oscillations, which remain stable over repeated evocations, are impaired by the stress hormone corticotropin-releasing factor (CRF, 125 nM) in vitro and, even more remarkably, found that they are accompanied by concurrent states of enforced theta activity in the memory-associated perirhinal cortex (PrC) in vivo. The latter phenomenon most likely derives from neurotransmission via a known, but poorly studied excitatory CA1→PrC pathway. Collectively, our data provide evidence for the existence of a prototypic (CRF-sensitive) P-I gamma rhythm generator in area CA1 and suggest that CA1 P-I oscillations can rapidly up-regulate theta activity strength in hippocampus-innervated rhinal networks, at least in the PrC. PMID:27199662

  14. Local Optogenetic Induction of Fast (20-40 Hz) Pyramidal-Interneuron Network Oscillations in the In Vitro and In Vivo CA1 Hippocampus: Modulation by CRF and Enforcement of Perirhinal Theta Activity.

    PubMed

    Dine, Julien; Genewsky, Andreas; Hladky, Florian; Wotjak, Carsten T; Deussing, Jan M; Zieglgänsberger, Walter; Chen, Alon; Eder, Matthias

    2016-01-01

    The neurophysiological processes that can cause theta-to-gamma frequency range (4-80 Hz) network oscillations in the rhinal cortical-hippocampal system and the potential connectivity-based interactions of such forebrain rhythms are a topic of intensive investigation. Here, using selective Channelrhodopsin-2 (ChR2) expression in mouse forebrain glutamatergic cells, we were able to locally, temporally precisely, and reliably induce fast (20-40 Hz) field potential oscillations in hippocampal area CA1 in vitro (at 25°C) and in vivo (i.e., slightly anesthetized NEX-Cre-ChR2 mice). As revealed by pharmacological analyses and patch-clamp recordings from pyramidal cells and GABAergic interneurons in vitro, these light-triggered oscillations can exclusively arise from sustained suprathreshold depolarization (~200 ms or longer) and feedback inhibition of CA1 pyramidal neurons, as being mandatory for prototypic pyramidal-interneuron network (P-I) oscillations. Consistently, the oscillations comprised rhythmically occurring population spikes (generated by pyramidal cells) and their frequency increased with increasing spectral power. We further demonstrate that the optogenetically driven CA1 oscillations, which remain stable over repeated evocations, are impaired by the stress hormone corticotropin-releasing factor (CRF, 125 nM) in vitro and, even more remarkably, found that they are accompanied by concurrent states of enforced theta activity in the memory-associated perirhinal cortex (PrC) in vivo. The latter phenomenon most likely derives from neurotransmission via a known, but poorly studied excitatory CA1→PrC pathway. Collectively, our data provide evidence for the existence of a prototypic (CRF-sensitive) P-I gamma rhythm generator in area CA1 and suggest that CA1 P-I oscillations can rapidly up-regulate theta activity strength in hippocampus-innervated rhinal networks, at least in the PrC.

  15. Temperature dependence of intensities of the 8-12 micron bands of CFCl3

    NASA Technical Reports Server (NTRS)

    Nanes, R.; Silvaggio, P. M.; Boese, R. W.

    1980-01-01

    The absolute intensities of the 8-12 micron bands from Freon 11 (CFCl3) were measured at temperatures of 294 and 216 K. Intensities of the bands centered at 798, 847, 934, and 1082 per cm are all observed to depend on temperature. The temperature dependence for the 847 and 1082 per cm fundamental regions is attributed to underlying hot bands; for the nu2 + nu5 combination band (934 per cm), the observed temperature dependence is in close agreement with theoretical prediction. The implication of these results on atmospheric IR remote-sensing is briefly discussed.

  16. Enhancement of Cortical Network Activity in vitro and Promotion of GABAergic Neurogenesis by Stimulation with an Electromagnetic Field with a 150 MHz Carrier Wave Pulsed with an Alternating 10 and 16 Hz Modulation.

    PubMed

    Gramowski-Voß, Alexandra; Schwertle, Hans-Joachim; Pielka, Anna-Maria; Schultz, Luise; Steder, Anne; Jügelt, Konstantin; Axmann, Jürgen; Pries, Wolfgang

    2015-01-01

    In recent years, various stimuli were identified capable of enhancing neurogenesis, a process which is dysfunctional in the senescent brain and in neurodegenerative and certain neuropsychiatric diseases. Applications of electromagnetic fields to brain tissue have been shown to affect cellular properties and their importance for therapies in medicine is recognized. In this study, differentiating murine cortical networks on multiwell microelectrode arrays were repeatedly exposed to an extremely low-electromagnetic field (ELEMF) with alternating 10 and 16 Hz frequencies piggy backed onto a 150 MHz carrier frequency. The ELEMF exposure stimulated the electrical network activity and intensified the structure of bursts. Further, the exposure to electromagnetic fields within the first 28 days in vitro of the differentiation of the network activity induced also reorganization within the burst structure. This effect was already most pronounced at 14 days in vitro after 10 days of exposure. Overall, the development of cortical activity under these conditions was accelerated. These functional electrophysiological changes were accompanied by morphological ones. The percentage of neurons in the neuron glia co-culture was increased without affecting the total number of cells, indicating an enhancement of neurogenesis. The ELEMF exposure selectively promoted the proliferation of a particular population of neurons, evidenced by the increased proportion of GABAergic neurons. The results support the initial hypothesis that this kind of ELEMF stimulation could be a treatment option for specific indications with promising potential for CNS applications, especially for degenerative diseases, such as Alzheimer's disease and other dementias.

  17. Estimation of broadband emissivity (8-12 um) from ASTER data by using RM-NN.

    PubMed

    Mao, K B; Ma, Y; Shen, X Y; Li, B P; Li, C Y; Li, Z L

    2012-08-27

    Land surface window emissivity is a key parameter for estimating the longwave radiative budget. The combined radiative transfer model (RM) with neural network (NN) algorithm is utilized to directly estimate the window (8-12 um) emissivity from the brightness temperature of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) with 90 m spatial resolution. Although the estimation accuracy is very high when the broadband emissivity is estimated from AST05 (ASTER Standard Data Product) by using regression method, the accuracy of AST05 is about ± 0.015 for 86 spectra which is determined by the atmosphere correction for ASTER 1B data. The MODTRAN 4 is used to simulate the process of radiance transfer, and the broadband emissivity is directly estimated from the brightness temperature of ASTER 1B data at satellite. The comparison analysis indicates that the RM-NN is more competent to estimate broadband emissivity than other method when the brightness temperatures of band 11, 12, 13, 14 are made as input nodes of dynamic neural network. The estimation average accuracy is about 0.009, and the estimation results are not sensitive to instrument noise. The RM-NN is applied to extract broadband emissivity from an image of ASTER 1B data in China, and the comparison against a classification based multiple bands with 15 m spatial resolution shows that the estimation results from RM-NN are very good.

  18. Chromosomal translocation t(8;12) induces aberrant HMGIC expression in aggressive angiomyxoma of the vulva.

    PubMed

    Nucci, M R; Weremowicz, S; Neskey, D M; Sornberger, K; Tallini, G; Morton, C C; Quade, B J

    2001-10-01

    Benign mesenchymal neoplasms associated with rearrangements of the DNA architectural factor gene HMGIC on chromosome 12 include lipomas, uterine leiomyomata, pulmonary chondroid hamartomas, endometrial polyps, salivary gland pleomorphic adenomas, and breast fibroadenomas. Although HMGIC also has been implicated in the pathobiology of aggressive angiomyxoma of the vulva, the molecular mechanisms pertaining to this neoplasm are unclear. Tissue from a recurrent aggressive angiomyxoma was investigated by cytogenetic and expression analysis for HMGIC and HMGIY. The trypsin-Giemsa-banded karyotype showed a clonal translocation between chromosomes 8 and 12 [46,XX,t(8;12)(p12;q15)]. Fluorescence in situ hybridization (FISH) analysis with whole chromosome paint probes for chromosomes 8 and 12 excluded cryptic involvement of other chromosomes. The chromosome 12 breakpoint was mapped with two-color FISH analysis using cosmid probes at the 5' and 3' termini of HMGIC. Both cosmid probes showed hybridization to the normal chromosome 12 and the der(12) chromosome, indicating that the breakpoint was 3' (telomeric) to the gene. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed HMGIC expression in the tumor, and immunohistochemistry localized HMGIC expression to the tumor's spindle cells. Like numerous benign mesenchymal tumors, this locally aggressive tumor is associated with rearrangements near or within HMGIC, but chimeric gene formation was not required for tumorigenesis. Inappropriate expression of this DNA binding protein, however, may be important in the pathobiology of this tumor. Understanding the pathogenetic mechanism may also be helpful in developing new diagnostic tools for identifying residual disease.

  19. Development of chick embryos in 1 Hz to 100 kHz magnetic fields.

    PubMed

    Juutilainen, J; Saali, K

    1986-01-01

    Chick embryos were exposed during their 48 first hours of development to sinusoidally oscillating magnetic fields. The frequencies 1 Hz, 10 Hz, 16.7 Hz, 30 Hz, 50 Hz, 1 kHz, 10 kHz and 100 kHz, and the field strengths 0.1, 1, 10 and 100 A/m were used. Each exposure group consisted of 20 eggs. After the exposure, the embryos were examined for abnormalities and classified by the developmental stage. The percentage of abnormal embryos (%AE) was significantly increased at frequencies from 16.7 Hz to 100 kHz. Above a threshold field strength of about 0.1 to 1 A/m, %AE was rather independent of the field strength, varying from 16% to 56% in different exposure groups. 13% of the sham-exposed control embryos (n = 150) were abnormal. Only the 0.1 A/m exposure group differed significantly from the controls at 1 Hz, and no significant effect was found at 10 Hz. The developmental stage was in general not affected by the magnetic fields, but some abnormal embryos showed retarded development.

  20. Are the 1/3-Octave Band 63- and 125-Hz Noise Levels Predictive of Vessel Activity? The Case in the Cres-Lošinj Archipelago (Northern Adriatic Sea, Croatia).

    PubMed

    Picciulin, Marta; Sebastianutto, Linda; Fortuna, Caterina Maria; Mackelworth, Peter; Holcer, Draško; Gospić, Nikolina Rako

    2016-01-01

    A 3-years sea ambient-noise (SAN) monitoring was carried out in the Cres-Lošinj Archipelago (Croatia), where a bottlenose dolphin population is threatened by unregulated nautical tourism. A total of 540 5-min SAN samples were collected and analyzed in an Indicator 11.2.1 (Marine Strategy Framework Directive) perspective. The 1/3-octave band center frequencies of 63 and 125 Hz (re 1 μPa.rms) proved to be predictive of local predominant ship type over time. However, the noisiest band level was centered on 200 Hz. We therefore suggest measuring a wider frequency band than those requested in Indicator 11.2.1.

  1. Coherent 40-Hz Oscillation Characterizes Dream State in Humans

    NASA Astrophysics Data System (ADS)

    Llinas, Rodolfo; Ribary, Urs

    1993-03-01

    Magnetic recording from five normal human adults demonstrates large 40-Hz coherent magnetic activity in the awake and in rapid-eye-movement (REM) sleep states that is very reduced during delta sleep (deep sleep characterized by delta waves in the electroencephalogram). This 40-Hz magnetic oscillation has been shown to be reset by sensory stimuli in the awake state. Such resetting is not observed during REM or delta sleep. The 40 Hz in REM sleep is characterized, as is that in the awake state, by a fronto-occiptal phase shift over the head. This phase shift has a maximum duration of thickapprox12-13 msec. Because 40-Hz oscillation is seen in wakefulness and in dreaming, we propose it to be a correlate of cognition, probably resultant from coherent 40-Hz resonance between thalamocortical-specific and nonspecific loops. Moreover, we proposed that the specific loops give the content of cognition, and a nonspecific loop gives the temporal binding required for the unity of cognitive experience.

  2. Audiogram of the chicken (Gallus gallus domesticus) from 2 Hz to 9 kHz.

    PubMed

    Hill, Evan M; Koay, Gimseong; Heffner, Rickye S; Heffner, Henry E

    2014-10-01

    The pure-tone thresholds of four domestic female chickens were determined from 2 Hz to 9 kHz using the method of conditioned suppression/avoidance. At a level of 60 dB sound pressure level (re 20 μN/m(2)), their hearing range extends from 9.1 Hz to 7.2 kHz, with a best sensitivity of 2.6 dB at 2 kHz. Chickens have better sensitivity than humans for frequencies below 64 Hz; indeed, their sensitivity to infrasound exceeds that of the homing pigeon. However, when threshold testing moved to the lower frequencies, the animals required additional training before their final thresholds were obtained, suggesting that they may perceive frequencies below 64 Hz differently than higher frequencies. PMID:25092127

  3. Preferential expression of the systemic lupus erythematosus-associated idiotype 8.12 in sera containing monoclonal immunoglobulins.

    PubMed

    Livneh, A; Preud'Homme, J L; Solomon, A; Diamond, B

    1987-12-01

    The 8.12 idiotype defines a population of anti-DNA antibodies present in the serum of patients with systemic lupus erythematosus. As part of our studies to elucidate the genetic origin and structural features of anti-DNA antibodies, we examined monoclonal immunoglobulin (Ig)-containing sera from 706 patients for expression of the 8.12 idiotype. We found 41 such sera to have significant 8.12 reactivity (greater than 4 SD above the mean of normal controls) and demonstrated that in 24 of these sera (8 IgM, 14 IgG, and 2 IgA) this reactivity could be localized to the monoclonal protein. In addition, 12 of the 8.12-reactive monoclonal Ig (11 IgG and 1 IgA) bind dsDNA. In the other 17 sera, the 8.12 reactivity could be attributed to polyclonal antibody. These findings provide further evidence that the serum monoclonal Ig frequently express the antigenic and idiotypic reactivities of autoantibodies. Furthermore, these data support the contention that anti-DNA specificity may result from somatic diversification of germ-line Ig gene sequences. PMID:3119715

  4. Are the 1/3-Octave Band 63- and 125-Hz Noise Levels Predictive of Vessel Activity? The Case in the Cres-Lošinj Archipelago (Northern Adriatic Sea, Croatia).

    PubMed

    Picciulin, Marta; Sebastianutto, Linda; Fortuna, Caterina Maria; Mackelworth, Peter; Holcer, Draško; Gospić, Nikolina Rako

    2016-01-01

    A 3-years sea ambient-noise (SAN) monitoring was carried out in the Cres-Lošinj Archipelago (Croatia), where a bottlenose dolphin population is threatened by unregulated nautical tourism. A total of 540 5-min SAN samples were collected and analyzed in an Indicator 11.2.1 (Marine Strategy Framework Directive) perspective. The 1/3-octave band center frequencies of 63 and 125 Hz (re 1 μPa.rms) proved to be predictive of local predominant ship type over time. However, the noisiest band level was centered on 200 Hz. We therefore suggest measuring a wider frequency band than those requested in Indicator 11.2.1. PMID:26611038

  5. Detection of Neural Activity Associated with Thinking in Frontal Lobe by Magnetoencephalograpy

    NASA Astrophysics Data System (ADS)

    Nishimura, K.; Tobinaga, Y.; Tonoike, M.

    We measured brain activity in normal subjects using magnetoencephalography while they were presented a series of thinking tasks intended to induce the natural thought. Changes in the spontaneous brain activity were assessed with a Super-conducting Quantum Interference Device (SQUID) neuromagnetometer. We detected transitions in the active portions of the brain during non-thinking tasks by analyzing brain magnetic filed of the frontal lobe in each various frequency range, α wave (8-12Hz), β wave (12-24Hz), γ wave (24-60Hz), and θ wave (4-8Hz). The α wave in the left hemisphere was more prominent than and waves, a distinctive feature of brain activity of the non-thinking state in our study. In addition, the α wave was prominent in the left hemisphere throughout every task including the non-thinking task.

  6. An Exercise in Using the U.S. Environmental Protection Agency's Hazard Ranking System: A Simulation. Grades 8-12.

    ERIC Educational Resources Information Center

    HAZWRAP, The Hazardous Waste Remedial Actions Program.

    The educational objective of this exercise is for students to use a risk assessment tool to evaluate a hazardous release site and for students in grades 8-12 to increase their experience with geology, aquifers, soils, land use, pollution, data analysis, and map concepts. Students use background information on hazardous materials, the Environmental…

  7. Career Education Program, 1980-1981, Columbia County School System. Teacher Guide, Grades 8-12. [Revised].

    ERIC Educational Resources Information Center

    Central Savannah River Area Cooperative Educational Services Agency, Thomson, GA.

    This guide contains a variety of materials to help teachers for grades 8-12 (specifically those in the Columbia County School System, Georgia) infuse career education into their classrooms. Contents include both school system-specific and general information: (1) brief discussion of career education; (2) listing of nine student outcome objectives;…

  8. 38 CFR 8.12 - Payment of the cash value of National Service Life Insurance in monthly installments under...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of National Service Life Insurance in monthly installments under section 1917(e) of title 38 U.S.C. 8... SERVICE LIFE INSURANCE Cash Value and Policy Loan § 8.12 Payment of the cash value of National Service Life Insurance in monthly installments under section 1917(e) of title 38 U.S.C. (a) Effective January...

  9. 38 CFR 8.12 - Payment of the cash value of National Service Life Insurance in monthly installments under...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... of National Service Life Insurance in monthly installments under section 1917(e) of title 38 U.S.C. 8... SERVICE LIFE INSURANCE Cash Value and Policy Loan § 8.12 Payment of the cash value of National Service Life Insurance in monthly installments under section 1917(e) of title 38 U.S.C. (a) Effective January...

  10. 38 CFR 8.12 - Payment of the cash value of National Service Life Insurance in monthly installments under...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... of National Service Life Insurance in monthly installments under section 1917(e) of title 38 U.S.C. 8... SERVICE LIFE INSURANCE Cash Value and Policy Loan § 8.12 Payment of the cash value of National Service Life Insurance in monthly installments under section 1917(e) of title 38 U.S.C. (a) Effective January...

  11. 38 CFR 8.12 - Payment of the cash value of National Service Life Insurance in monthly installments under...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... of National Service Life Insurance in monthly installments under section 1917(e) of title 38 U.S.C. 8... SERVICE LIFE INSURANCE Cash Value and Policy Loan § 8.12 Payment of the cash value of National Service Life Insurance in monthly installments under section 1917(e) of title 38 U.S.C. (a) Effective January...

  12. 38 CFR 8.12 - Payment of the cash value of National Service Life Insurance in monthly installments under...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... of National Service Life Insurance in monthly installments under section 1917(e) of title 38 U.S.C. 8... SERVICE LIFE INSURANCE Cash Value and Policy Loan § 8.12 Payment of the cash value of National Service Life Insurance in monthly installments under section 1917(e) of title 38 U.S.C. (a) Effective January...

  13. Thomson Scattering at 250 kHz

    NASA Astrophysics Data System (ADS)

    Young, William; den Hartog, D. J.; Morton, L. A.; MST Team

    2015-11-01

    The fast Thomson scattering diagnostic on the MST Reversed-Field Pinch experiment now measures electron temperature at rates of up to 250 kHz, allowing for single shot analysis of phenomena that previously required ensembles of measurements from many shots. Recent laser upgrades include the addition of a second Nd:glass amplifier (giving a total of six amplifiers including four Nd:YAG stages) and optimization of neodymium doping levels within the glass amplifier stages to reduce thermal defocusing. The master-oscillator power-amplifier laser system operates in a pulse-burst mode where the laser generates multiple pulses per flashlamp firing and these bursts of laser pulses are repeated multiple times. When optimizing for the largest number of laser pulses, the laser produces up to 30 pulses at a rate of 100 kHz per burst repeated up to 4 times every 2 ms for a total of 120 temperature measurements per MST discharge. When optimizing for fastest pulsing rate, the laser can produce 8 pulses at 250 kHz within a single burst. A laser system upgrade currently underway is replacement of the diode-pumped pulsed Nd:YVO4 master oscillator with a CW laser chopped by an acoustic-optic modulator; this upgrade may enable pulsing rates faster than 250 kHz. This work is supported by the US DOE and NSF.

  14. Quantification of Interictal Neuromagnetic Activity in Absence Epilepsy with Accumulated Source Imaging.

    PubMed

    Xiang, Jing; Tenney, Jeffrey R; Korman, Abraham M; Leiken, Kimberly; Rose, Douglas F; Harris, Elana; Yuan, Weihong; Horn, Paul S; Holland, Katherine; Loring, David W; Glauser, Tracy A

    2015-11-01

    Aberrant brain activity in childhood absence epilepsy (CAE) during seizures has been well recognized as synchronous 3 Hz spike-and-wave discharges on electroencephalography. However, brain activity from low- to very high-frequency ranges in subjects with CAE between seizures (interictal) has rarely been studied. Using a high-sampling rate magnetoencephalography (MEG) system, we studied ten subjects with clinically diagnosed but untreated CAE in comparison with age- and gender-matched controls. MEG data were recorded from all subjects during the resting state. MEG sources were assessed with accumulated source imaging, a new method optimized for localizing and quantifying spontaneous brain activity. MEG data were analyzed in nine frequency bands: delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (12-30 Hz), low-gamma (30-55 Hz), high-gamma (65-90 Hz), ripple (90-200 Hz), high-frequency oscillation (HFO, 200-1,000 Hz), and very high-frequency oscillation (VHFO, 1,000-2,000 Hz). MEG source imaging revealed that subjects with CAE had higher odds of interictal brain activity in 200-1,000 and 1,000-2,000 Hz in the parieto-occipito-temporal junction and the medial frontal cortices as compared with controls. The strength of the interictal brain activity in these regions was significantly elevated in the frequency bands of 90-200, 200-1,000 and 1,000-2,000 Hz for subjects with CAE as compared with controls. The results indicate that CAE has significantly aberrant brain activity between seizures that can be noninvasively detected. The measurements of high-frequency neuromagnetic oscillations may open a new window for investigating the cerebral mechanisms of interictal abnormalities in CAE. PMID:25359158

  15. Sounds in the ocean at 1-100 Hz.

    PubMed

    Wilcock, William S D; Stafford, Kathleen M; Andrew, Rex K; Odom, Robert I

    2014-01-01

    Very-low-frequency sounds between 1 and 100 Hz propagate large distances in the ocean sound channel. Weather conditions, earthquakes, marine mammals, and anthropogenic activities influence sound levels in this band. Weather-related sounds result from interactions between waves, bubbles entrained by breaking waves, and the deformation of sea ice. Earthquakes generate sound in geologically active regions, and earthquake T waves propagate throughout the oceans. Blue and fin whales generate long bouts of sounds near 20 Hz that can dominate regional ambient noise levels seasonally. Anthropogenic sound sources include ship propellers, energy extraction, and seismic air guns and have been growing steadily. The increasing availability of long-term records of ocean sound will provide new opportunities for a deeper understanding of natural and anthropogenic sound sources and potential interactions between them. PMID:23876176

  16. Sounds in the ocean at 1-100 Hz.

    PubMed

    Wilcock, William S D; Stafford, Kathleen M; Andrew, Rex K; Odom, Robert I

    2014-01-01

    Very-low-frequency sounds between 1 and 100 Hz propagate large distances in the ocean sound channel. Weather conditions, earthquakes, marine mammals, and anthropogenic activities influence sound levels in this band. Weather-related sounds result from interactions between waves, bubbles entrained by breaking waves, and the deformation of sea ice. Earthquakes generate sound in geologically active regions, and earthquake T waves propagate throughout the oceans. Blue and fin whales generate long bouts of sounds near 20 Hz that can dominate regional ambient noise levels seasonally. Anthropogenic sound sources include ship propellers, energy extraction, and seismic air guns and have been growing steadily. The increasing availability of long-term records of ocean sound will provide new opportunities for a deeper understanding of natural and anthropogenic sound sources and potential interactions between them.

  17. The Exploration of Mars. Educational Brief: Planetary Science, Grades 8-12.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Washington, DC.

    This booklet gives a history of human observations of Mars, including observations made from U.S. unmanned spacecraft. Also included is a discussion, "Encountering a New World: How to Explore a Planet," which contains classroom discussion questions and four classroom activities. The classroom activities include: (1) How to explore a planet; (2)…

  18. The 2 Hz and 15 Hz electroacupuncture induced reverse effect on autonomic function in healthy adult using a heart rate variability analysis

    PubMed Central

    Jia, Bor-An; Cheng, Chin-Yi; Lin, Yi-Wen; Li, Tsai-Chung; Liu, Hsu-Jan; Hsieh, Ching-Liang

    2011-01-01

    The purpose of the present study was to investigate effect of electro-acupuncture (EA) at different frequencies on autonomic function. Twenty healthy adult volunteers were studied, and underwent 4 sessions of EA (sham, 2 Hz, 15 Hz, and 50 Hz). Sham, 2 Hz, 15 Hz, and 50 Hz EA was applied to the bilateral Leg Three Li (足三里 zú sān lǐ, ST-36) and Upper Great Hollow (上巨虛 shàng jù xū, ST-37) acupoints. The intensity of electrical stimulation was adjusted to obtain visible twitching of the anterior tibial muscle about 2.0-2.5 mA except sham without electrical stimulation. The components of heart rate variability (HRV) and blood pressure were measured before EA (BLP), EA (EAP), and post-EA periods (PEP). The results indicated that the natural logarithmic high frequency power (lnHF) of HRV was greater during PEP than during the BLP in the 2 Hz EA sessions. The natural logarithmic low frequency power (lnLF) of HRV was greater during the PEP than during the BLP in 15 Hz EA sessions, suggesting that 2 Hz EA apply to Leg Three Li (足三里 zú sān lǐ, ST-36) and Upper Great Hollow (上巨虛 shàng jù xū, ST-37) acupoints increased vagal activity, whereas 15 Hz EA increased sympathetic activity. PMID:24716105

  19. Effect of level, duration, and inter-pulse interval of 1-2 kHz sonar signal exposures on harbor porpoise hearing.

    PubMed

    Kastelein, Ronald A; Hoek, Lean; Gransier, Robin; Rambags, Martijn; Claeys, Naomi

    2014-07-01

    Safety criteria for underwater low-frequency active sonar sounds produced during naval exercises are needed to protect harbor porpoise hearing. As a first step toward defining criteria, a porpoise was exposed to sequences consisting of series of 1-s, 1-2 kHz sonar down-sweeps without harmonics (as fatiguing noise) at various combinations of average received sound pressure levels (SPLs; 144-179 dB re 1 μPa), exposure durations (1.9-240 min), and duty cycles (5%-100%). Hearing thresholds were determined for a narrow-band frequency-swept sine wave centered at 1.5 kHz before exposure to the fatiguing noise, and at 1-4, 4-8, 8-12, 48, 96, 144, and 1400 min after exposure, to quantify temporary threshold shifts (TTSs) and recovery of hearing. Results show that the inter-pulse interval of the fatiguing noise is an important parameter in determining the magnitude of noise-induced TTS. For the reported range of exposure combinations (duration and SPL), the energy of the exposure (i.e., cumulative sound exposure level; SELcum) can be used to predict the induced TTS, if the inter-pulse interval is known. Exposures with equal SELcum but with different inter-pulse intervals do not result in the same induced TTS.

  20. RHIC 10 Hz global orbit feedback system

    SciTech Connect

    Michnoff, R.; Arnold, L.; Carboni, L.; Cerniglia, P; Curcio, A.; DeSanto, L.; Folz, C.; Ho, C.; Hoff, L.; Hulsart, R.; Karl, R.; Luo, Y.; Liu, C.; MacKay, W.; Mahler, G.; Meng, W.; Mernick, K.; Minty, M.; Montag, C.; Olsen, R.; Piacentino, J.; Popken, P.; Przybylinski, R.; Ptitsyn, V.; Ritter, J.; Schoenfeld, R.; Thieberger, P.; Tuozzolo, J.; Weston, A.; White, J.; Ziminski, P.; Zimmerman, P.

    2011-03-28

    Vibrations of the cryogenic triplet magnets at the Relativistic Heavy Ion Collider (RHIC) are suspected to be causing the horizontal beam perturbations observed at frequencies around 10 Hz. Several solutions to counteract the effect have been considered in the past, including a local beam feedback system at each of the two experimental areas, reinforcing the magnet base support assembly, and a mechanical servo feedback system. However, the local feedback system was insufficient because perturbation amplitudes outside the experimental areas were still problematic, and the mechanical solutions are very expensive. A global 10 Hz orbit feedback system consisting of 36 beam position monitors (BPMs) and 12 small dedicated dipole corrector magnets in each of the two 3.8 km circumference counter-rotating rings has been developed and commissioned in February 2011. A description of the system architecture and results with beam will be discussed.

  1. Spectroscopic observations of HZ Herculis. II

    NASA Technical Reports Server (NTRS)

    Bopp, B. W.; Grupsmith, G.; Mcmillan, R. S.; Vanden Bout, P. A.; Wootten, H. A.

    1973-01-01

    Preliminary results from an extensive series of spectroscopic observations of the HZ Her optical counterpart of the eclipsing, pulsating X-ray binary Her X-1. Spectrograms with a dispersion of 30 A/mm reveal a spectral type as late as F5 near minimum in the light curve with the G-band and metallic lines present. Narrow Fe lines show that HZ Her is not a rapid rotator. Low-dispersion (115 A/mm) spectra, obtained with 10-minute time resolution, reveal rapid (10-min) variations in the 4640 N III emission and in the 4471 He I absorbtion features. The H-beta absorption is variable in equivalent width, and shows evidence of being partially filled with emission.

  2. Humans perceive flicker artifacts at 500 Hz

    NASA Astrophysics Data System (ADS)

    Davis, James; Hsieh, Yi-Hsuan; Lee, Hung-Chi

    2015-02-01

    Humans perceive a stable average intensity image without flicker artifacts when a television or monitor updates at a sufficiently fast rate. This rate, known as the critical flicker fusion rate, has been studied for both spatially uniform lights, and spatio-temporal displays. These studies have included both stabilized and unstablized retinal images, and report the maximum observable rate as 50-90 Hz. A separate line of research has reported that fast eye movements known as saccades allow simple modulated LEDs to be observed at very high rates. Here we show that humans perceive visual flicker artifacts at rates over 500 Hz when a display includes high frequency spatial edges. This rate is many times higher than previously reported. As a result, modern display designs which use complex spatio-temporal coding need to update much faster than conventional TVs, which traditionally presented a simple sequence of natural images.

  3. The 10 Hz Frequency: A Fulcrum For Transitional Brain States

    PubMed Central

    Garcia-Rill, E.; D’Onofrio, S.; Luster, B.; Mahaffey, S.; Urbano, F. J.; Phillips, C.

    2016-01-01

    A 10 Hz rhythm is present in the occipital cortex when the eyes are closed (alpha waves), in the precentral cortex at rest (mu rhythm), in the superior and middle temporal lobe (tau rhythm), in the inferior olive (projection to cerebellar cortex), and in physiological tremor (underlying all voluntary movement). These are all considered resting rhythms in the waking brain which are “replaced” by higher frequency activity with sensorimotor stimulation. That is, the 10 Hz frequency fulcrum is replaced on the one hand by lower frequencies during sleep, or on the other hand by higher frequencies during volition and cognition. The 10 Hz frequency fulcrum is proposed as the natural frequency of the brain during quiet waking, but is replaced by higher frequencies capable of permitting more complex functions, or by lower frequencies during sleep and inactivity. At the center of the transition shifts to and from the resting rhythm is the reticular activating system, a phylogenetically preserved area of the brain essential for preconscious awareness. PMID:27547831

  4. STS-109 Mission Highlights Resource Tape. Part 4 of 4; Flight Days 8 - 12

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This video, Part 4 of 4, shows footage of crew activities from flight days 8 through 12 of STS-109. The crew included: Scott Altman, Commander; Duane Carey, Pilot; John Grunsfeld, Payload Commander; Nancy Currie, Richard Linnehan, James Newman, Michael Massimino, Mission Speicalists. The activities from other flights days can be seen on 'STS-109 Mission Highlights Resource Tape' Part 1 of 4 (internal ID 2002139471), 'STS-109 Mission Highlights Resource Tape' Part 2 of 4 (internal ID 2002137664), and 'STS-109 Mission Highlights Resource Tape' Part 3 of 4 (internal ID 2002139476). The primary activity on flight day 8 was an EVA (extravehicular activity) by Grunsfeld and Linnehan to install a cryocooler and radiator for the NICMOS (Near Infrared Camera and Multi-Object Spectrometer) on the HST (Hubble Space Telescope). Before returning to Columbia's airlock, the astronauts, with a cloudy background, hold onto the orbiter and offer their thoughts on the significance of their mission, the HST, and spaceflight. Footage from flight day 9 includes the grappling, unbearthing, and deployment of the HST from Columbia, and the crew coordinating and videotaping Columbia's departure. Flight day 10 was a relatively inactive day, and flight day 11 includes a checkout of Columbia's aerodynamic surfaces. Columbia landed on flight day 12, which is covered by footage of the crew members speaking during reentry, and their night landing, primarily shown through the orbiter's head-up display. The video includes numerous views of the HST, as well as views of the the Galapagos Islands, Madagascar, and Southern Africa with parts of the Atlantic, Indian, and Pacific Oceans, and part of the coast of Chile. The pistol grip space tool is shown in use, and the crew answers two messages from the public, including a message to Massimino from the Fire Department of New York.

  5. 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...

  6. On-Going Frontal Alpha Rhythms Are Dominant in Passive State and Desynchronize in Active State in Adult Gray Mouse Lemurs.

    PubMed

    Infarinato, Francesco; Rahman, Anisur; Del Percio, Claudio; Lamberty, Yves; Bordet, Regis; Richardson, Jill C; Forloni, Gianluigi; Drinkenburg, Wilhelmus; Lopez, Susanna; Aujard, Fabienne; Babiloni, Claudio; Pifferi, Fabien

    2015-01-01

    The gray mouse lemur (Microcebus murinus) is considered a useful primate model for translational research. In the framework of IMI PharmaCog project (Grant Agreement n°115009, www.pharmacog.org), we tested the hypothesis that spectral electroencephalographic (EEG) markers of motor and locomotor activity in gray mouse lemurs reflect typical movement-related desynchronization of alpha rhythms (about 8-12 Hz) in humans. To this aim, EEG (bipolar electrodes in frontal cortex) and electromyographic (EMG; bipolar electrodes sutured in neck muscles) data were recorded in 13 male adult (about 3 years) lemurs. Artifact-free EEG segments during active state (gross movements, exploratory movements or locomotor activity) and awake passive state (no sleep) were selected on the basis of instrumental measures of animal behavior, and were used as an input for EEG power density analysis. Results showed a clear peak of EEG power density at alpha range (7-9 Hz) during passive state. During active state, there was a reduction in alpha power density (8-12 Hz) and an increase of power density at slow frequencies (1-4 Hz). Relative EMG activity was related to EEG power density at 2-4 Hz (positive correlation) and at 8-12 Hz (negative correlation). These results suggest for the first time that the primate gray mouse lemurs and humans may share basic neurophysiologic mechanisms of synchronization of frontal alpha rhythms in awake passive state and their desynchronization during motor and locomotor activity. These EEG markers may be an ideal experimental model for translational basic (motor science) and applied (pharmacological and non-pharmacological interventions) research in Neurophysiology. PMID:26618512

  7. The effect of 10 Hz transcranial alternating current stimulation (tACS) on corticomuscular coherence

    PubMed Central

    Wach, Claudia; Krause, Vanessa; Moliadze, Vera; Paulus, Walter; Schnitzler, Alfons; Pollok, Bettina

    2013-01-01

    Synchronous oscillatory activity at alpha (8–12 Hz), beta (13–30 Hz), and gamma (30–90 Hz) frequencies is assumed to play a key role for motor control. Corticomuscular coherence (CMC) represents an established measure of the pyramidal system's integrity. Transcranial alternating current stimulation (tACS) offers the possibility to modulate ongoing oscillatory activity. Behaviorally, 20 Hz tACS in healthy subjects has been shown to result in movement slowing. However, the neurophysiological changes underlying these effects are not entirely understood yet. The present study aimed at ascertaining the effects of tACS at 10 and 20 Hz in healthy subjects on CMC and local power of the primary sensorimotor cortex. Neuromagnetic activity was recorded during isometric contraction before and at two time points (2–10 min and 30–38 min) after tACS of the left primary motor cortex (M1), using a 306 channel whole head magnetoencephalography (MEG) system. Additionally, electromyography (EMG) of the right extensor digitorum communis (EDC) muscle was measured. TACS was applied at 10 and 20 Hz, respectively, for 10 min at 1 mA. Sham stimulation served as control condition. The data suggest that 10 Hz tACS significantly reduced low gamma band CMC during isometric contraction. This implies that tACS does not necessarily cause effects at stimulation frequency. Rather, the findings suggest cross-frequency interplay between alpha and low gamma band activity modulating functional interaction between motor cortex and muscle. PMID:24009573

  8. 4 Hz oscillations synchronize prefrontal-amygdala circuits during fear behaviour

    PubMed Central

    Karalis, Nikolaos; Dejean, Cyril; Chaudun, Fabrice; Khoder, Suzana; Rozeske, Robert R.; Wurtz, Hélène; Bagur, Sophie; Benchenane, Karim; Sirota, Anton; Courtin, Julien; Herry, Cyril

    2016-01-01

    Fear expression relies on the coordinated activity of prefrontal and amygdala circuits, yet the mechanisms allowing long-range network synchronization during fear remain unknown. Using a combination of extracellular recordings, pharmacological, and optogenetic manipulations we report that freezing, a behavioural expression of fear, temporally coincides with the development of sustained, internally generated 4 Hz oscillations within prefrontal-amygdala circuits. 4 Hz oscillations predict freezing onset and offset and synchronize prefrontal-amygdala circuits. Optogenetic induction of prefrontal 4 Hz oscillations coordinates prefrontal-amygdala activity and elicits fear behaviour. These results unravel a novel sustained oscillatory mechanism mediating prefrontal-amygdala coupling during fear behaviour. PMID:26878674

  9. 4-Hz oscillations synchronize prefrontal-amygdala circuits during fear behavior.

    PubMed

    Karalis, Nikolaos; Dejean, Cyril; Chaudun, Fabrice; Khoder, Suzana; Rozeske, Robert R; Wurtz, Hélène; Bagur, Sophie; Benchenane, Karim; Sirota, Anton; Courtin, Julien; Herry, Cyril

    2016-04-01

    Fear expression relies on the coordinated activity of prefrontal and amygdala circuits, yet the mechanisms allowing long-range network synchronization during fear remain unknown. Using a combination of extracellular recordings, pharmacological and optogenetic manipulations, we found that freezing, a behavioral expression of fear, temporally coincided with the development of sustained, internally generated 4-Hz oscillations in prefrontal-amygdala circuits. 4-Hz oscillations predict freezing onset and offset and synchronize prefrontal-amygdala circuits. Optogenetic induction of prefrontal 4-Hz oscillations coordinates prefrontal-amygdala activity and elicits fear behavior. These results unravel a sustained oscillatory mechanism mediating prefrontal-amygdala coupling during fear behavior. PMID:26878674

  10. 4-Hz oscillations synchronize prefrontal-amygdala circuits during fear behavior.

    PubMed

    Karalis, Nikolaos; Dejean, Cyril; Chaudun, Fabrice; Khoder, Suzana; Rozeske, Robert R; Wurtz, Hélène; Bagur, Sophie; Benchenane, Karim; Sirota, Anton; Courtin, Julien; Herry, Cyril

    2016-04-01

    Fear expression relies on the coordinated activity of prefrontal and amygdala circuits, yet the mechanisms allowing long-range network synchronization during fear remain unknown. Using a combination of extracellular recordings, pharmacological and optogenetic manipulations, we found that freezing, a behavioral expression of fear, temporally coincided with the development of sustained, internally generated 4-Hz oscillations in prefrontal-amygdala circuits. 4-Hz oscillations predict freezing onset and offset and synchronize prefrontal-amygdala circuits. Optogenetic induction of prefrontal 4-Hz oscillations coordinates prefrontal-amygdala activity and elicits fear behavior. These results unravel a sustained oscillatory mechanism mediating prefrontal-amygdala coupling during fear behavior.

  11. Environmental and Pharmacological Modulation of Amphetamine-Induced 50-kHz Ultrasonic Vocalizations in Rats

    PubMed Central

    Rippberger, Henrike; van Gaalen, Marcel M.; Schwarting, Rainer K.W.; WÖhr, Markus

    2015-01-01

    Rats emit high-frequency 50-kHz ultrasonic vocalizations (USV) in appetitive situations like social interactions. Drugs of abuse are probably the most potent non-social elicitors of 50-kHz USV, possibly reflecting their euphorigenic properties. Psychostimulants induce the strongest elevation in 50-kHz USV emission, particularly amphetamine (AMPH), either when applied systemically or locally into the nucleus accumbens (Nacc). Emission of AMPH-induced 50-kHz USV depends on test context, such as the presence of conspecifics, and can be manipulated pharmacologically by targeting major neurotransmitter systems, including dopamine (DA), noradrenaline (NA), and serotonin (5-HT), but also protein kinase C (PKC) signaling. Several D1 and D2 receptor antagonists, as well as typical and atypical antipsychotics block the AMPH-induced elevation in 50-kHz USV. Inhibiting D1 and D2 receptors in the Nacc abolishes AMPH-induced 50-kHz USV, indicating a key role for this brain area. NA neurotransmission also regulates AMPH-induced 50-kHz USV emission given that α1 receptor antagonists and α2 receptor agonists exert attenuating effects. Supporting the involvement of the 5-HT system, AMPH-induced 50-kHz USV are attenuated by 5-HT2C receptor activation, whereas 5-HT2C receptor antagonism leads to the opposite effect. Finally, treatment with lithium, tamoxifen, and myricitrin was all found to result in a complete abolishment of the AMPH-induced increase in 50-kHz USV, suggesting the involvement of PKC signaling. Neurotransmitter systems involved in AMPH-induced 50-kHz USV emission only partially overlap with other AMPH-induced behaviors like hyperlocomotion. The validity of AMPH-induced 50-kHz USV as a preclinical model for neuropsychiatric disorders is discussed, particularly with relevance to altered drive and mood seen in bipolar disorder. PMID:26411764

  12. Synthesis of 4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane (TEX) Using Heteropolyacids as Efficient and Recyclable Heterogeneous Catalysts

    NASA Astrophysics Data System (ADS)

    Bayat, Yadollah; Azizkhani, Vahid

    2012-07-01

    4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane (TEX) is well known as an efficient explosive compound. It is usually prepared via nitration of a precursor with a mixture of concentrated nitric and sulfuric acid. However, there are many difficulties with the use of old methods, such as strong acidic and thermal conditions, which cause product decomposition, low yields, hazardous wastes, and product separation difficulties. In this article, the use of an efficient catalytic and mild reaction conditions for TEX synthesis is reported for the first time. It has been well documented that heteropolyacids (HPAs) are efficient green catalysts for use as a nitric acid activator. This strategy provided milder and higher yield conditions for nitration reactions. In addition, the reactions can be reasonably run at lower temperatures in a short time.

  13. Hearing thresholds of a harbor porpoise (Phocoena phocoena) for sweeps (1-2 kHz and 6-7 kHz bands) mimicking naval sonar signals.

    PubMed

    Kastelein, Ronald A; Hoek, Lean; de Jong, Christ A F

    2011-05-01

    The distance at which active naval sonar signals can be heard by harbor porpoises depends, among other factors, on the hearing thresholds of the species for those signals. Therefore the hearing sensitivity of a harbor porpoise was determined for 1 s up-sweep and down-sweep signals, mimicking mid-frequency and low-frequency active sonar sweeps (MFAS, 6-7 kHz band; LFAS, 1-2 kHz band). The 1-2 kHz sweeps were also tested with harmonics, as sonars sometimes produce these as byproducts of the fundamental signal. The hearing thresholds for up-sweeps and down-sweeps within each sweep pair were similar. The 50% detection threshold sound pressure levels (broadband, averaged over the signal duration) of the 1-2 kHz and 6-7 kHz sweeps were 75 and 67 dB re 1 μPa(2), respectively. Harmonic deformation of the 1-2 kHz sweeps reduced the threshold to 59 dB re 1 μPa(2). This study shows that the presence of harmonics in sonar signals can increase the detectability of a signal by harbor porpoises, and that tonal audiograms may not accurately predict the audibility of sweeps. LFAS systems, when designed to produce signals without harmonics, can operate at higher source levels than MFAS systems, at similar audibility distances for porpoises.

  14. Turkish validity and reliability of a pediatric quality of life cancer module for children aged 8-12 and parents.

    PubMed

    Tanir, Meltem Kurtuncu; Kuguoglu, Sema

    2011-01-01

    This descriptive study was conducted to determine the validity and reliability in Turkey of the Pediatric Quality of Life Inventory Cancer Module (PedsQL 3.0) for children aged 8-12 in the hematology-oncology polyclinics of two university hospitals in Istanbul during the period 2006-2007. The data collection instruments were the Pediatric Quality of Life Inventory (PedsQL 4.0), the Pediatric Quality of Life Inventory Cancer Module (PedsQL 3.0) and a socio-demographic questionnaire, applied for 146 children diagnosed with cancer and 146 parents. Cronbach's alpha coefficients for the PedsQL 3.0 were found to be 0.602-0.982 for sub-groups with the children's form, 0.644-0.966 with the parents' form. The scale was found to give a significantly high level of reliability (0.60 ≤ ± < 0.80). Significant and directly proportional correlations were demonstrated between the forms for children and parents. It was concluded that the PedsQL 3.0 cancer module is a valid and reliable tool for assessing the quality of life of Turkish children, aged 8-12, diagnosed with cancer.

  15. Ambient noise measurements from 100 Hz to 80 kHz in an Alaskan fjord.

    PubMed

    McConnell, S O; Schilt, M P; Dworski, J G

    1992-04-01

    Measurements covering a broad frequency range from 100 Hz to 80 kHz have been made in Behm Canal, Alaska. This site represents a fairly deep embayment (400 m) with a soft bottom (porosity of about 0.8) and, hence, the noise detected at the hydrophones is affected negligibly by multipath contributions except possibly at the lowest frequencies. Data were gathered over a wide range of wind speeds (0 to 15 m/s) and during periods of rain and snow. Several unique and noteworthy results were obtained. Foremost was the observation that the wind-generated noise level measured during the winter was approximately 5 dB lower than during the summer for the same wind speeds and air-sea temperature differences (air temperature about the same as or colder than the sea surface). The summer data agree well with the most recent published measurements and are approximately 2 dB higher than the standard Knudsen/Wenz reference spectra. It appeared that below-freezing air temperatures and snow were responsible for the 5 dB offset between the summer and winter data. Most reported wind noise measurements are restricted to frequencies less than 20 kHz. Those that go beyond this frequency display a noticeable hump above the usual--17 dB/decade power-law slope, and the Behm Canal measurements show that this hump continues to 80 kHz where the spectrum rejoins the extension of the canonical power-law slope.

  16. PET imaging of the 40 Hz auditory steady state response.

    PubMed

    Reyes, Samuel A; Salvi, Richard J; Burkard, Robert F; Coad, Mary Lou; Wack, David S; Galantowicz, Paul J; Lockwood, Alan H

    2004-08-01

    The auditory steady state response (aSSR) is an oscillatory electrical potential recorded from the scalp induced by amplitude-modulated (AM) or click/tone burst stimuli. Its clinical utility has been limited by uncertainty regarding the specific areas of the brain involved in its generation. To identify the generators of the aSSR, 15O-water PET imaging was used to locate the regions of the brain activated by a steady 1 kHz pure tone, the same tone amplitude modulated (AM) at 40 Hz and the specific regions of the brain responsive to the AM component of the stimulus relative to the continuous tone. The continuous tone produced four clusters of activation. The boundaries of these activated clusters extended to include regions in left primary auditory cortex, right non-primary auditory cortex, left thalamus, and left cingulate. The AM tone produced three clusters of activation. The boundaries of these activated clusters extended to include primary auditory cortex bilaterally, left medial geniculate and right middle frontal gyrus. Two regions were specifically responsive to the AM component of the stimulus. These activated clusters extended to include the right anterior cingulate near frontal cortex and right auditory cortex. We conclude that cortical sites, including areas outside primary auditory cortex, are involved in generating the aSSR. There was an unexpected difference between morning and afternoon session scans that may reflect a pre- versus post-prandial state. These results support the hypothesis that a distributed resonating circuit mediates the generation of the aSSR.

  17. 47 CFR 80.882 - 2182 kHz watch.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false 2182 kHz watch. 80.882 Section 80.882 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE... kHz watch. Ships subject to this subpart must maintain a watch on the frequency 2182 kHz pursuant...

  18. 47 CFR 80.882 - 2182 kHz watch.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false 2182 kHz watch. 80.882 Section 80.882 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE... kHz watch. Ships subject to this subpart must maintain a watch on the frequency 2182 kHz pursuant...

  19. 47 CFR 80.882 - 2182 kHz watch.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false 2182 kHz watch. 80.882 Section 80.882 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE... kHz watch. Ships subject to this subpart must maintain a watch on the frequency 2182 kHz pursuant...

  20. 47 CFR 80.882 - 2182 kHz watch.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false 2182 kHz watch. 80.882 Section 80.882 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE... kHz watch. Ships subject to this subpart must maintain a watch on the frequency 2182 kHz pursuant...

  1. 47 CFR 80.882 - 2182 kHz watch.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false 2182 kHz watch. 80.882 Section 80.882 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE... kHz watch. Ships subject to this subpart must maintain a watch on the frequency 2182 kHz pursuant...

  2. Thomson scattering at 250 kHz

    NASA Astrophysics Data System (ADS)

    Young, W. C.; Den Hartog, D. J.

    2015-12-01

    Several upgrades have been applied to the high-repetition-rate Thomson scattering diagnostic on the MST experiment, having increased the rate and number of electron temperature measurements. The detector portion of the Thomson scattering system requires 1.5-2.0 J, 10-20 ns laser pulses at 1064 nm. A high-repetition-rate laser produces suitable pulses for short 3-4 pulse bursts with only 3 μs pulse spacing. Alternatively, the laser timing can be optimized to maximize the number of pulses in a single burst, producing up to 44 pulses at a rate of 100 kHz. The laser follows a master oscillator, power amplifier architecture. Upgrades to the laser include: a new acousto-optic modulator chopped CW laser based master oscillator, a sixth power amplifier, optimized Nd doping within Nd:glass amplifiers via optical modeling of the pump chamber, and a yet to be installed new cavity reflector. Additionally, a new long wavelength filter has been added to the Thomson scattering diagnostic's polychromator based detector, allowing possible detection of net electron drift.

  3. Discovery of 1-5 Hz flaring at high luminosity in SAX J1808.4-3658

    SciTech Connect

    Bult, Peter; Van der Klis, Michiel

    2014-07-10

    We report the discovery of a 1-5 Hz X-ray flaring phenomenon observed at >30 mCrab near peak luminosity in the 2008 and 2011 outbursts of the accreting millisecond X-ray pulsar SAX J1808.4-3658 in observations with the Rossi X-ray Timing Explorer. In each of the two outbursts this high luminosity flaring is seen for ∼3 continuous days and switches on and off on a timescale of 1-2 hr. The flaring can be seen directly in the light curve, where it shows sharp spikes of emission at quasi-regular separation. In the power spectrum it produces a broad noise component, which peaks at 1-5 Hz. The total 0.05-10 Hz variability has a fractional rms amplitude of 20%-45%, well in excess of the 8%-12% rms broadband noise usually seen in power spectra of SAX J1808.4-3658. We perform a detailed timing analysis of the flaring and study its relation to the 401 Hz pulsations. We find that the pulse amplitude varies proportionally with source flux through all phases of the flaring, indicating that the flaring is likely due to mass density variations created at or outside the magnetospheric boundary. We suggest that this 1-5 Hz flaring is a high mass accretion rate version of the 0.5-2 Hz flaring which is known to occur at low luminosity (<13 mCrab), late in the tail of outbursts of SAX J1808.4-3658. We propose the dead-disk instability, previously suggested as the mechanism for the 0.5-2 Hz flaring, as a likely mechanism for the high luminosity flaring reported here.

  4. Validity and interunit reliability of 10 Hz and 15 Hz GPS units for assessing athlete movement demands.

    PubMed

    Johnston, Richard J; Watsford, Mark L; Kelly, Stephen J; Pine, Matthew J; Spurrs, Robert W

    2014-06-01

    The purpose of this study was to assess the validity and interunit reliability of 10 Hz (Catapult) and 15 Hz (GPSports) Global Positioning System (GPS) units and investigate the differences between these units as measures of team sport athlete movement demands. A team sport simulation circuit was completed by 8 trained male participants. The movement demands examined included: total distance covered (TD), average peak speed, and the distance covered, time spent, and the number of efforts performed low-speed running (0.00-13.99 km · h(-1)), high-speed running (14.00-19.99 km · h(-1)), and very high-speed running (>20.00 km · h(-1)). The degree of difference between the 10 Hz and the 15 Hz GPS units and validity was assessed using a paired samples t-test. Pearson's correlations were also used for validity assessment. Interunit reliability was established using percentage typical error of measurement (%TEM) and intraclass correlations. The findings revealed that 10 Hz GPS units were a valid (p > 0.05) and reliable (%TEM = 1.3%) measure of TD. In contrast, the 15 Hz GPS units exhibited lower validity for TD and average peak speed. Further, as the speed of movement increased the level of error for the 10 Hz and 15 Hz GPS units increased (%TEM = 0.8-19.9). The findings from this study suggest that comparisons should not be undertaken between 10 Hz and 15 Hz GPS units. In general, the 10 Hz GPS units measured movement demands with greater validity and interunit reliability than the 15 Hz units, however, both 10 Hz and 15 Hz units provided the improved measures of movement demands in comparison to 1 Hz and 5 Hz GPS units.

  5. Investigation of effects of 60-Hz electric and magnetic fields on operant and social behavior and on the neuroendocrine system of nonhuman primates. Quarterly report, Scan and activity data for experiments 4 and 4A, [July 1, 1992--September 30, 1992

    SciTech Connect

    Smith, H.D.

    1992-11-02

    The objective of this program is to investigate behavioral and neuroendocrine effects associated with exposure to 60-Hz electric and magnetic fields (E/MF), using the baboon surrogate for the human. Baboon social groups were scanned and electronically monitored during Experiments IV and IVA. The social scan, form that the technicians used to identify baboon locations and proximity to other baboons: was used to gain a simple snapshot of the position of the baboons in their cage. The scans were taken hourly every morning and evening for a total of eight scans per side per day. This report covers in detail the scan and activity data-gathering process. A set of appendices is attached which include printouts of the data sets and adjunct material pertinent to interpreting the data. The supporting material is comprised of calendars and listings of major events that occurred during the scan and activity data collection.

  6. Long-term underwater sound measurements in the shipping noise indicator bands 63Hz and 125Hz from the port of Falmouth Bay, UK.

    PubMed

    Garrett, J K; Blondel, Ph; Godley, B J; Pikesley, S K; Witt, M J; Johanning, L

    2016-09-15

    Chronic low-frequency anthropogenic sound, such as shipping noise, may be negatively affecting marine life. The EU's Marine Strategy Framework Directive (MSFD) includes a specific indicator focused on this noise. This indicator is the yearly average sound level in third-octave bands with centre frequencies at 63Hz and 125Hz. These levels are described for Falmouth Bay, UK, an active port at the entrance to the English Channel. Underwater sound was recorded for 30min h(-1) over the period June 2012 to November 2013 for a total of 435days. Mean third-octave levels were louder in the 125-Hz band (annual mean level of 96.0dB re 1μPa) than in the 63-Hz band (92.6dB re 1 μPa). These levels and variations are assessed as a function of seasons, shipping activity and wave height, providing comparison points for future monitoring activities, including the MSFD and emerging international regulation.

  7. Long-term underwater sound measurements in the shipping noise indicator bands 63Hz and 125Hz from the port of Falmouth Bay, UK.

    PubMed

    Garrett, J K; Blondel, Ph; Godley, B J; Pikesley, S K; Witt, M J; Johanning, L

    2016-09-15

    Chronic low-frequency anthropogenic sound, such as shipping noise, may be negatively affecting marine life. The EU's Marine Strategy Framework Directive (MSFD) includes a specific indicator focused on this noise. This indicator is the yearly average sound level in third-octave bands with centre frequencies at 63Hz and 125Hz. These levels are described for Falmouth Bay, UK, an active port at the entrance to the English Channel. Underwater sound was recorded for 30min h(-1) over the period June 2012 to November 2013 for a total of 435days. Mean third-octave levels were louder in the 125-Hz band (annual mean level of 96.0dB re 1μPa) than in the 63-Hz band (92.6dB re 1 μPa). These levels and variations are assessed as a function of seasons, shipping activity and wave height, providing comparison points for future monitoring activities, including the MSFD and emerging international regulation. PMID:27393210

  8. BOLD fractional contribution to resting-state functional connectivity above 0.1 Hz.

    PubMed

    Chen, Jingyuan E; Glover, Gary H

    2015-02-15

    Blood oxygen level dependent (BOLD) spontaneous signals from resting-state (RS) brains have typically been characterized by low-pass filtered timeseries at frequencies ≤ 0.1 Hz, and studies of these low-frequency fluctuations have contributed exceptional understanding of the baseline functions of our brain. Very recently, emerging evidence has demonstrated that spontaneous activities may persist in higher frequency bands (even up to 0.8 Hz), while presenting less variable network patterns across the scan duration. However, as an indirect measure of neuronal activity, BOLD signal results from an inherently slow hemodynamic process, which in fact might be too slow to accommodate the observed high-frequency functional connectivity (FC). To examine whether the observed high-frequency spontaneous FC originates from BOLD contrast, we collected RS data as a function of echo time (TE). Here we focus on two specific resting state networks - the default-mode network (DMN) and executive control network (ECN), and the major findings are fourfold: (1) we observed BOLD-like linear TE-dependence in the spontaneous activity at frequency bands up to 0.5 Hz (the maximum frequency that can be resolved with TR=1s), supporting neural relevance of the RSFC at a higher frequency range; (2) conventional models of hemodynamic response functions must be modified to support resting state BOLD contrast, especially at higher frequencies; (3) there are increased fractions of non-BOLD-like contributions to the RSFC above the conventional 0.1 Hz (non-BOLD/BOLD contrast at 0.4-0.5 Hz is ~4 times that at <0.1 Hz); and (4) the spatial patterns of RSFC are frequency-dependent. Possible mechanisms underlying the present findings and technical concerns regarding RSFC above 0.1 Hz are discussed.

  9. Participation in life situations of 8-12 year old children with cerebral palsy: cross sectional European study

    PubMed Central

    Fauconnier, Jérôme; Dickinson, Heather O; Beckung, Eva; Marcelli, Marco; McManus, Vicki; Michelsen, Susan I; Parkes, Jackie; Parkinson, Kathryn N; Thyen, Ute; Arnaud, Catherine

    2009-01-01

    Objectives To evaluate how involvement in life situations (participation) in children with cerebral palsy varies with type and severity of impairment and to investigate geographical variation in participation. Design Cross sectional study. Trained interviewers visited parents of children with cerebral palsy; multilevel multivariable regression related participation to impairments, pain, and sociodemographic characteristics. Setting Eight European regions with population registers of children with cerebral palsy; one further region recruited children from multiple sources. Participants 1174 children aged 8-12 with cerebral palsy randomly selected from the population registers, 743 (63%) joined in the study; the further region recruited 75 children. Main outcome measure Children’s participation assessed by the Life-H questionnaire covering 10 main areas of daily life. Scoring ignored adaptations or assistance required for participation. Results Children with pain and those with more severely impaired walking, fine motor skills, communication, and intellectual abilities had lower participation across most domains. Type of cerebral palsy and problems with feeding and vision were associated with lower participation for specific domains, but the sociodemographic factors examined were not. Impairment and pain accounted for up to a sixth of the variation in participation. Participation on all domains varied substantially between regions: children in east Denmark had consistently higher participation than children in other regions. For most participation domains, about a third of the unexplained variation could be ascribed to variation between regions and about two thirds to variation between individuals. Conclusions Participation in children with cerebral palsy should be assessed in clinical practice to guide intervention and assess its effect. Pain should be carefully assessed. Some European countries facilitate participation better than others, implying some countries

  10. The validation and comparison of the GOCI aerosol optical thickness products: a case study of Tianjin 8.12

    NASA Astrophysics Data System (ADS)

    Yao, Lingling; Zhang, Xiaoyu; Yu, Hui; Jiang, Binbin

    2016-01-01

    COMSGOCI (Geostationary Ocean Color Imager) is the first geostationary ocean color satellite in the world launched by South Korea in June 2010, which includes eight bands from the visible to the infrared band. GOCI aerosol optical thickness (AOT) at 555nm was retrieved by atmospheric radiative transfer model based on two-stream approximation algorithm. Due to GOCI without near infrared band and has a high solar elevation angle, solar zenith angle must be recalibrated to solve the earth system albedo, and the surface reflectance solved by quack atmospheric correction and recalculated backward scatter coefficient. Evaluation of GOCIAOT with AERONET measurements showed that the average error becomes 0.107 from the original 0.393, that means GOCI aerosol optical thickness can be more accurately with the advanced two-stream approximation. Taking the eastern China in 3 and 4 December 2013 for example, comparing the GOCIAOT at 555nm, MODISAOT retrievals at 550nm, NPPAOT at 550nm and AERONET data products indicated that: take the AERONET data as reference, the error of three kinds of satellite data can be ordered as following: MODISAOT< GOCIAOT< NPPAOT and the GOCI-MODIS shows a bias of 0.02917 with the GOCI-NPP. GOCIAOT is 0.05714 generally bigger than that of MODISAOT. NPP-GOCI deviation is 0.10253. The deficiency of MODIS is its low spatial resolution and the high concentration of AOT will be mistaken for a cloud area. However, GOCI can well reflect the concentration and distribution of aerosols. Therefore, GOGI can provide real-time dynamic monitoring on China Eastern atmospheric environment and the accurate time event information of haze for each process can be obtained. Finally, applied GOCI to the "8.12 Tianjin bombings" and to monitor the migration and dispersion of pollutant.

  11. development of a medium repetition rate (10 Hz - 500 Hz) diode pumped laser transmitter for airborne scanning altimetry

    NASA Technical Reports Server (NTRS)

    Coyle, D. Barry; Lindauer, Steven J., II; Kay, Richard B.

    1998-01-01

    Since the late 1980's, NASA has developed several small, all-solid state lasers of low repetition rates for use as transmitters in prototype LIDAR and raster scanned altimetry retrieval systems. Our early laser transmitters were developed for high resolution airborne altimetry which employed cavity dumping techniques to produce a pulse shape with a 1 ns rise time. The first such laser was the SUMR (Sub-millimeter resolution) transmitter which used a side pumped, D-shaped half-rod of Nd:YAG for the oscillator active media and produced approximately 3 ns pulses of 100 micro-J energy at a 40 Hz repetition rate. (Coyle and Blair, 1993; Coyle et al., 1995) After several upgrades to improve rep rate and pulse energy, the final version produced 1.2 mJ pulses at 120 Hz with a 3.7 ns pulse width. The laser has become known as SPLT (Sharp Pulsed Laser Transmitter), and has flown successfully on a variety of airborne altimetry missions. (Coyle and Blair, 1995; Blair et al., 1994) From building these systems, we have accrued valuable experience in delivering field-deployable lasers and have become aware of the advantages and disadvantages of employing new technologies. For example, even though the laser's main operating environment is in a "cold" aircraft during flight, the laser must still operate in very warm temperatures. This is important if the mission is based in the desert or a tropical climate since ground calibration data from stationary targets must be gathered before and after each data flight. Because conductive cooling is much more convenient than closed loop water flow, achieving the highest possible laser efficiency is becoming a high priority when designing a flight laser. This is especially true for lasers with higher pulse energies and repetition rates which are needed for high altitude scanning altimeters and LIDARs.

  12. 40 Hz auditory steady state response to linguistic features of stimuli during auditory hallucinations.

    PubMed

    Ying, Jun; Yan, Zheng; Gao, Xiao-rong

    2013-10-01

    The auditory steady state response (ASSR) may reflect activity from different regions of the brain, depending on the modulation frequency used. In general, responses induced by low rates (≤40 Hz) emanate mostly from central structures of the brain, and responses from high rates (≥80 Hz) emanate mostly from the peripheral auditory nerve or brainstem structures. Besides, it was reported that the gamma band ASSR (30-90 Hz) played an important role in working memory, speech understanding and recognition. This paper investigated the 40 Hz ASSR evoked by modulated speech and reversed speech. The speech was Chinese phrase voice, and the noise-like reversed speech was obtained by temporally reversing the speech. Both auditory stimuli were modulated with a frequency of 40 Hz. Ten healthy subjects and 5 patients with hallucination symptom participated in the experiment. Results showed reduction in left auditory cortex response when healthy subjects listened to the reversed speech compared with the speech. In contrast, when the patients who experienced auditory hallucinations listened to the reversed speech, the auditory cortex of left hemispheric responded more actively. The ASSR results were consistent with the behavior results of patients. Therefore, the gamma band ASSR is expected to be helpful for rapid and objective diagnosis of hallucination in clinic. PMID:24142731

  13. Harmonics of 60 Hz in power systems caused by geomagnetic disturbances. [Manitoba

    NASA Technical Reports Server (NTRS)

    Hayashi, K.; Oguti, T.; Watanabe, T.; Tsuruda, K.; Kokubun, S.; Horita, R. E.

    1979-01-01

    Simultaneous VLF/ULF observations carried out near Winnipeg, Manitoba show that geomagnetic disturbances control the behavior of harmonics of 60 Hz man-made electric power. The harmonics of 60 Hz detected by the VLF receiver are at multiples of 180 Hz, indicating that they originated from a 3 phase ac power system. Under geomagnetically quiet conditions, only odd harmonics of 70 Hz were detected. In disturbed conditions, both odd and even harmonics were excited. The strength of each harmonic changed concurrently with geomagnetic pulsation (ULF) activity. These findings seem to indicate that a portion of telluric currents shunted into the power line system through the neutrals of the Y-connected transformers give rise to a dc bias to the transformer core materials and that it distorts their hysteresis loops, activating harmonics of 60 Hz power. A mathematical proof is given that a hysteresis loop having a point of symmetry generates odd harmonics only, whereas loops lacking in point-symmetry generally give rise to both odd and even harmonics. A general formula was obtained to calculate the strength of each harmonic based on the shape of the hysteresis loop.

  14. Modulation of the ∽20-Hz motor-cortex rhythm to passive movement and tactile stimulation

    PubMed Central

    Parkkonen, Eeva; Laaksonen, Kristina; Piitulainen, Harri; Parkkonen, Lauri; Forss, Nina

    2015-01-01

    Background Integration of afferent somatosensory input with motor-cortex output is essential for accurate movements. Prior studies have shown that tactile input modulates motor-cortex excitability, which is reflected in the reactivity of the ∽20-Hz motor-cortex rhythm. ∽20-Hz rebound is connected to inhibition or deactivation of motor cortex whereas suppression has been associated with increased motor cortex activity. Although tactile sense carries important information for controlling voluntary actions, proprioception likely provides the most essential feedback for motor control. Methods To clarify how passive movement modulates motor-cortex excitability, we studied with magnetoencephalography (MEG) the amplitudes and peak latencies of suppression and rebound of the ∽20-Hz rhythm elicited by tactile stimulation and passive movement of right and left index fingers in 22 healthy volunteers. Results Passive movement elicited a stronger and more robust ∽20-Hz rebound than tactile stimulation. In contrast, the suppression amplitudes did not differ between the two stimulus types. Conclusion Our findings suggest that suppression and rebound represent activity of two functionally distinct neuronal populations. The ∽20-Hz rebound to passive movement could be a suitable tool to study the functional state of the motor cortex both in healthy subjects and in patients with motor disorders. PMID:25874163

  15. 60 HZ beam motion reduction at NSLS UV storage ring

    SciTech Connect

    Singh, O.V.

    1997-01-01

    A significant reduction in 60 hz beam motion has been achieved in the UV storage ring. From the wide band harmonic beam motion signal, 60 hz signal is extracted by tuned bandpass filter. This signal is processed by the phase and amplitude adjustment circuits and then, it is fed into the harmonic orbit generation circuits. Several harmonics, near the tune, were canceled by employing one circuit for each harmonic. The design and description of this experiment is given in this paper. The results showing reduction in beam motion at 60 hz are also provided.

  16. The 40-Hz auditory steady-state response: a selective biomarker for cortical NMDA function.

    PubMed

    Sivarao, Digavalli V

    2015-05-01

    When subjected to a phasic input, sensory cortical neurons display a remarkable ability to entrain faithfully to the driving stimuli. The entrainment to rhythmic sound stimuli is often referred to as the auditory steady-state response (ASSR) and can be captured using noninvasive techniques, such as scalp-recorded electroencephalography (EEG). An ASSR to a driving frequency of approximately 40 Hz is particularly interesting in that it shows, in relative terms, maximal power, synchrony, and synaptic activity. Moreover, the 40-Hz ASSR has been consistently found to be abnormal in schizophrenia patients across multiple studies. The nature of the reported abnormality has been less consistent; while most studies report a deficit in entrainment, several studies have reported increased signal power, particularly when there are concurrent positive symptoms, such as auditory hallucinations. However, the neuropharmacological basis for the 40-Hz ASSR, as well as its dysfunction in schizophrenia, has been unclear until recently. On the basis of several recent reports, it is argued that the 40-Hz ASSR represents a specific marker for cortical NMDA transmission. If confirmed, the 40-Hz ASSR may be a simple and easy-to-access pharmacodynamic biomarker for testing the integrity of cortical NMDA neurotransmission that is robustly translational across species. PMID:25809615

  17. Deficits in the 30-Hz auditory steady-state response in patients with major depressive disorder.

    PubMed

    Chen, Jingjing; Gong, Qin; Wu, Fei

    2016-10-19

    The auditory steady-state response (ASSR) is an auditory evoked potential that occurs in response to periodically presented auditory stimuli. The ASSR has drawn attention as a biomarker of psychiatric disorders owing to its connection with neural oscillations as well as its easy and noninvasive recording. Abnormalities in the γ band ASSR have been found consistently in patients with schizophrenia and bipolar disorder. However, although major depressive disorder (MDD) is also part of the common psychiatric diseases, the relationship between the ASSR and MDD has not been characterized sufficiently. Thus, the aim of the present study was to examine the ASSRs from patients with MDD and compare them with those from healthy control (HC) participants. The experiment was designed to obtain the ASSRs elicited by 20-, 30-, and 40-Hz click trains. Patients and HCs were evaluated separately. The response power and phase synchronization were measured at each stimulation frequency. Patients with MDD showed significantly reduced ASSR power for 30-Hz stimuli compared with HC participants, whereas no significant differences in the power were observed at 20 and 40 Hz for patients with MDD. In addition, no significant difference in the phase synchronization was observed for 20-, 30-, and 40-Hz stimuli. Conclusively, patients with MDD were characterized by deficits in 30-Hz ASSR power, which may be associated with spontaneous γ activity dysfunction. The present findings suggest that ASSR could potentially be used as a biomarker for MDD. PMID:27563737

  18. Report of the First Meeting of the Governing Board, SEAMEO Regional Centre for Education in Science and Mathematics (Penang, Malaysia, October 8-12, 1970). Final Report.

    ERIC Educational Resources Information Center

    Southeast Asian Ministers of Education Organization (Singapore). Regional Center for Education in Science and Mathematics.

    This report details the proceedings of the first meeting of the Governing Board of the SEAMEO Regional Centre for Education in Science and Mathematics held in Penang, Malaysia from October 8-12, 1970. Procedural matters detailed in the report include: (1) the election of officers; (2) the acceptance of the annual report of the events and…

  19. Does greater low frequency EEG activity in normal immaturity and in children with epilepsy arise in the same neuronal network?

    PubMed

    Michels, L; Bucher, K; Brem, S; Halder, P; Lüchinger, R; Liechti, M; Martin, E; Jeanmonod, D; Kröll, J; Brandeis, D

    2011-03-01

    Greater low frequency power (<8 Hz) in the electroencephalogram (EEG) at rest is normal in the immature developing brain of children when compared to adults. Children with epilepsy also have greater low frequency interictal resting EEG activity. Whether these power elevations reflect brain immaturity due to a developmental lag or the underlying epileptic pathophysiology is unclear. The present study addresses this question by analyzing spectral EEG topographies and sources for normally developing children and children with epilepsy. We first compared the resting EEG of healthy children to that of healthy adults to isolate effects related to normal brain immaturity. Next, we compared the EEG from 10 children with generalized cryptogenic epilepsy to the EEG of 24 healthy children to isolate effects related to epilepsy. Spectral analysis revealed that global low (delta: 1-3 Hz, theta: 4-7 Hz), medium (alpha: 8-12 Hz) and high (beta: 13-25 Hz) frequency EEG activity was greater in children without epilepsy compared to adults, and even further elevated for children with epilepsy. Topographical and tomographic EEG analyses showed that normal immaturity corresponded to greater delta and theta activity at fronto-central scalp and brain regions, respectively. In contrast, the epilepsy-related activity elevations were predominantly in the alpha band at parieto-occipital electrodes and brain regions, respectively. We conclude that lower frequency activity can be a sign of normal brain immaturity or brain pathology depending on the specific topography and frequency of the oscillating neuronal network. PMID:20820898

  20. Threshold received sound pressure levels of single 1-2 kHz and 6-7 kHz up-sweeps and down-sweeps causing startle responses in a harbor porpoise (Phocoena phocoena).

    PubMed

    Kastelein, Ronald A; Steen, Nele; Gransier, Robin; Wensveen, Paul J; de Jong, Christ A F

    2012-03-01

    Mid-frequency and low-frequency sonar systems produce frequency-modulated sweeps which may affect harbor porpoises. To study the effect of sweeps on behavioral responses (specifically "startle" responses, which we define as sudden changes in swimming speed and/or direction), a harbor porpoise in a large pool was exposed to three pairs of sweeps: a 1-2 kHz up-sweep was compared with a 2-1 kHz down-sweep, both with and without harmonics, and a 6-7 kHz up-sweep was compared with a 7-6 kHz down-sweep without harmonics. Sweeps were presented at five spatially averaged received levels (mRLs; 6 dB steps; identical for the up-sweep and down-sweep of each pair). During sweep presentation, startle responses were recorded. There was no difference in the mRLs causing startle responses for up-sweeps and down-sweeps within frequency pairs. For 1-2 kHz sweeps without harmonics, a 50% startle response rate occurred at mRLs of 133 dB re 1 μPa; for 1-2 kHz sweeps with strong harmonics at 99 dB re 1 μPa; for 6-7 kHz sweeps without harmonics at 101 dB re 1 μPa. Low-frequency (1-2 kHz) active naval sonar systems without harmonics can therefore operate at higher source levels than mid-frequency (6-7 kHz) active sonar systems without harmonics, with similar startle effects on porpoises.

  1. Activation and tremor of the shoulder muscles to the demands of an archery task.

    PubMed

    Lin, Jiu-Jenq; Hung, Cheng-Ju; Yang, Ching-Ching; Chen, Hsing-Yu; Chou, Feng-Ching; Lu, Tung-Wu

    2010-02-01

    Physiological tremor and strength during the maintenance of shoulder position occur during a precision aiming task, such as archery. It is unclear how positions for precision demands affect physiological tremor and associated muscular activities. The purpose of this study was to assess the tremor amplitude and muscular activities of the shoulder between the various positions for precision demands. Ten males (age 21.9 +/- 2.0 years) participated in the study. Electromyography (EMG) was quantified on eight humeral/scapular muscles. The tremor was measured by the acceleration component of a motion tracking sensor in the 3-7 Hz and 8-12 Hz frequency bands. Participants simulated six preparatory archery shooting positions (3 arm angles x 2 arm draw positions) and performed isometric contractions. The relative root mean square (RMS) amplitudes of the shoulder muscles were significantly greater for the full drawing position compared with the partial position (humeral muscles: P = 0.011; scapular muscles: P = 0.026). In the full drawing position, increased humeral/scapular muscle EMG amplitude was moderately associated with an increased power spectrum of 8-12/3-7 Hz tremor in humerus/scapula motion (R = 0.43-0.57). To minimize fluctuations in high strength muscle performance, 90 degrees of elevation in the full drawing position may be a suitable position for demands in archery. In addition, scapular muscle amplitude is important for stability to reduce humerus tremor during archery performance. PMID:20432134

  2. NASA Rat Acoustic Tolerance Test 1994-1995: 8 kHz, 16 kHz, 32 kHz Experiments

    NASA Technical Reports Server (NTRS)

    Mele, Gary D.; Holley, Daniel C.; Naidu, Sujata

    1996-01-01

    Adult male Sprague-Dawley rats were exposed to chronic applied sound (74 to 79 dB, SPL) with octave band center frequencies of either 8, 16 or 32 kHz for up to 60 days. Control cages had ambient sound levels of about 62 dB (SPL). Groups of rats (test vs. control; N=9 per group) were euthanized after 0. 5. 14, 30, and 60 days. On each euthanasia day, objective evaluation of their physiology and behavior was performed using a Stress Assessment Battery (SAB) of measures. In addition, rat hearing was assessed using the brain stem auditory evoked potential (BAER) method after 60 days of exposure. No statistically significant differences in mean daily food use could be attributed to the presence of the applied test sound. Test rats used 5% more water than control rats. In the 8 kHz and 32 kHz tests this amount was statistically significant(P less than .05). This is a minor difference of questionable physiological significance. However, it may be an indication of a small reaction to the constant applied sound. Across all test frequencies, day 5 test rats had 6% larger spleens than control rats. No other body or organ weight differences were found to be statistically significant with respect to the application of sound. This spleen effect may be a transient adaptive process related to adaptation to the constant applied noise. No significant test effect on differential white blood cell counts could be demonstrated. One group demonstrated a low eosinophil count (16 kHz experiment, day 14 test group). However this was highly suspect. Across all test frequencies studied, day 5 test rats had 17% fewer total leukocytes than day 5 control rats. Sound exposed test rats exhibited 44% lower plasma corticosterone concentrations than did control rats. Note that the plasma corticosterone concentration was lower in the sound exposed test animals than the control animals in every instance (frequency exposure and number of days exposed).

  3. 1-J operation of monolithic composite ceramics with Yb:YAG thin layers: multi-TRAM at 10-Hz repetition rate and prospects for 100-Hz operation.

    PubMed

    Divoky, Martin; Tokita, Shigeki; Hwang, Sungin; Kawashima, Toshiyuki; Kan, Hirofumi; Lucianetti, Antonio; Mocek, Tomas; Kawanaka, Junji

    2015-03-15

    Experimental amplification of 10-ns pulses to energy of 1 J at repetition rate of 10-100 Hz in cryogenic multipass total-reflection active-mirror (TRAM) amplifier is reported for the first time. By using a monolithic multi-TRAM, which is a YAG ceramic composite with three thin Yb:YAG active layers, efficient energy extraction was achieved without parasitic lasing. A detailed measurement of output characteristics of the laser amplifier is presented; results are discussed and compared with numerical calculations.

  4. Magnetic field tomography of coherent thalamocortical 40-Hz oscillations in humans

    SciTech Connect

    Ribary, U.; Lado, F.; Mogilner, A.; Llinas, R. ); Ioannides, A.A.; Singh, K.D.; Hasson, R.; Bolton, J.P.R. )

    1991-12-15

    This paper introduces the use of magnetic field tomography (MFT), a noninvasive technique based on distributed source analysis of magnetoencephalography data, which makes possible three-dimensional reconstruction of dynamic brain activity in humans. MFT has a temporal resolution better than 1 msec and a spatial accuracy of 2-5 mm at the cortical level, which deteriorates to 1-3 cm at depths of 6 cm or more. MFT is used here to visualize the origin of a spatiotemporally organized pattern of coherent 40-Hz electrical activity. This coherence, initially observed during auditory input, was proposed to be generated by recurrent corticothalamic oscillation. In support of this hypothesis, the authors illustrate well-defined 40-Hz coherence between cortical-subcortical sites with a time shift that is consistent with thalamocortical conduction times. Studies on Alzheimer patients indicate that, while a similar activity pattern is present, the cortical component is reduced in these subjects.

  5. Magnetic Field Tomography of Coherent Thalamocortical 40-Hz Oscillations in Humans

    NASA Astrophysics Data System (ADS)

    Ribary, U.; Ioannides, A. A.; Singh, K. D.; Hasson, R.; Bolton, J. P. R.; Lado, F.; Mogilner, A.; Llinas, R.

    1991-12-01

    This paper introduces the use of magnetic field tomography (MFT), a noninvasive technique based on distributed source analysis of magnetoencephalography data, which makes possible the three-dimensional reconstruction of dynamic brain activity in humans. MFT has a temporal resolution better than 1 msec and a spatial accuracy of 2-5 mm at the cortical level, which deteriorates to 1-3 cm at depths of 6 cm or more. MFT is used here to visualize the origin of a spatiotemporally organized pattern of coherent 40-Hz electrical activity. This coherence, initially observed during auditory input, was proposed to be generated by recurrent corticothalamic oscillation. In support of this hypothesis, we illustrate well-defined 40-Hz coherence between cortical-subcortical sites with a time shift that is consistent with thalamocortical conduction times. Studies on Alzheimer patients indicate that, while a similar activity pattern is present, the cortical component is reduced in these subjects.

  6. U.S. Department of Energy Hydrogen and Fuel Cells Program 2015 Annual Merit Review and Peer Evaluation Report: June 8-12, 2015, Arlington, Virginia

    SciTech Connect

    Popovich, Neil

    2015-10-01

    The fiscal year 2015 U.S. Department of Energy (DOE) Hydrogen and Fuel Cells Program Annual Merit Review and Peer Evaluation Meeting (AMR), in conjunction with DOE's Vehicle Technologies Office AMR, was held from June 8-12, 2015, in Arlington, Virginia. This report is a summary of comments by AMR peer reviewers about the hydrogen and fuel cell projects funded by DOE's Office of Energy Efficiency and Renewable Energy.

  7. Coherent neocortical 40-Hz oscillations are not present during REM sleep.

    PubMed

    Castro, Santiago; Falconi, Atilio; Chase, Michael H; Torterolo, Pablo

    2013-04-01

    During cognitive processes there are extensive interactions between various regions of the cerebral cortex. Oscillations in the gamma frequency band (≈40 Hz) of the electroencephalogram (EEG) are involved in the binding of spatially separated but temporally correlated neural events, which results in a unified perceptual experience. The extent of these interactions can be examined by means of a mathematical algorithm called 'coherence', which reflects the 'strength' of functional interactions between cortical areas. The present study was conducted to analyse EEG coherence in the gamma frequency band of the cat during alert wakefulness (AW), quiet wakefulness (QW), non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. Cats were implanted with electrodes in the frontal, parietal and occipital cortices to monitor EEG activity. Coherence values within the gamma frequency (30-100 Hz) from pairs of EEG recordings were analysed. A large increase in coherence occurred between all cortical regions in the 30-45 Hz frequency band during AW compared with the other behavioral states. As the animal transitioned from AW to QW and from QW to NREM sleep, coherence decreased to a moderate level. Remarkably, there was practically no EEG coherence in the entire gamma band spectrum (30-100 Hz) during REM sleep. We conclude that functional interactions between cortical areas are radically different during sleep compared with wakefulness. The virtual absence of gamma frequency coherence during REM sleep may underlie the unique cognitive processing that occurs during dreams, which is principally a REM sleep-related phenomenon. PMID:23406153

  8. Syllabic (~2-5 Hz) and fluctuation (~1-10 Hz) ranges in speech and auditory processing

    PubMed Central

    Edwards, Erik; Chang, Edward F.

    2013-01-01

    Given recent interest in syllabic rates (~2-5 Hz) for speech processing, we review the perception of “fluctuation” range (~1-10 Hz) modulations during listening to speech and technical auditory stimuli (AM and FM tones and noises, and ripple sounds). We find evidence that the temporal modulation transfer function (TMTF) of human auditory perception is not simply low-pass in nature, but rather exhibits a peak in sensitivity in the syllabic range (~2-5 Hz). We also address human and animal neurophysiological evidence, and argue that this bandpass tuning arises at the thalamocortical level and is more associated with non-primary regions than primary regions of cortex. The bandpass rather than low-pass TMTF has implications for modeling auditory central physiology and speech processing: this implicates temporal contrast rather than simple temporal integration, with contrast enhancement for dynamic stimuli in the fluctuation range. PMID:24035819

  9. Adenosine A(2A) receptor antagonists are broad facilitators of antinicotinic neuromuscular blockade monitored either with 2 Hz train-of-four or 50 Hz tetanic stimuli.

    PubMed

    Pereira, Monalisa W; Correia-de-Sá, Paulo; Alves-Do-Prado, Wilson

    2012-10-01

    1. The 2 Hz train-of-four ratio (TOF(ratio)) is used to monitor the degree of patient curarization. Using a rat phrenic nerve-hemidiaphragm preparation, we showed that antinicotinic agents, such as hexamethonium, d-tubocurarine and pancuronium, but not cisatracurium, decreased contractions produced by physiological nerve activity patterns (50 Hz) more efficiently than those caused by 2 Hz trains. Uncertainty about the usefulness of the TOF(ratio) to control safe recovery from curarization prompted us to investigate the muscarinic and adenosine neuromodulation of tetanic (50 Hz) fade induced by antinicotinic agents at concentrations that cause a 25% reduction in the TOF(ratio) (TOF(fade)). 2. Tetanic fade caused by d-tubocurarine (1.1 μmol/L), pancuronium (3 μmol/L) and hexamethonium (5.47 mmol/L) was attenuated by blocking presynaptic inhibitory muscarinic M(2) and adenosine A(1) receptors with methoctramine (1 μmol/L) and 1,3-dipropyl-8-cyclopentylxanthine (2.5 nmol/L), respectively. These compounds enhanced rather than decreased tetanic fade induced by cisatracurium (2.2 μmol/L), but they consistently attenuated cisatracurium-induced TOF(fade). The effect of the M(1) receptor antagonist pirenzepine (10 nmol/L) on fade produced by antinicotinic agents at 50 Hz was opposite to that observed with TOF stimulation. Blockade of adenosine A(2A) receptors with ZM 241385 (10 nmol/L) attenuated TOF(fade) caused by all antinicotinic drugs tested, with the exception of the 'pure' presynaptic nicotinic antagonist hexamethonium. ZM 241385 was the only compound tested in this series that facilitated recovery from tetanic fade produced by cisatracurium. 3. The data suggest that distinct antinicotinic relaxants interfere with fine-tuning neuromuscular adaptations to motor nerve stimulation patterns via activation of presynaptic muscarinic and adenosine receptors. These results support the use of A(2A) receptor antagonists together with atropine to facilitate recovery from

  10. Loading frequencies up to 20Hz as an alternative to accelerate fatigue strength tests in a Y-TZP ceramic.

    PubMed

    Fraga, Sara; Pereira, Gabriel Kalil Rocha; Freitas, Mariana; Kleverlaan, Cornelis Johannes; Valandro, Luiz Felipe; May, Liliana Gressler

    2016-08-01

    Considering the interest of the research community in the fatigue behavior of all-ceramic restorations and the time consumed in low-frequency cyclic fatigue tests, this study aimed to investigate the influence of the loading frequency on the zirconia fatigue strength. The biaxial flexural fatigue strength of Y-TZP discs was determined by the staircase approach after 500,000 cycles. The investigated frequencies were 2Hz (control-simulation of the chewing activity; n=20), 10Hz (n=20), 20Hz (n=20), and 40Hz (n=21). The fatigue strength data were analyzed using one-way ANOVA and post-hoc Tukey׳s test (α=0.05). Pearson coefficient (r) was calculated to assess the existence of a correlation between fatigue strength and loading frequency. X-ray diffraction analysis was used to determine the relative amount of monoclinic phase under each fatigue test condition. The fatigue strength was significantly higher for 40Hz group (630.7±62.1MPa) and did not differ among the groups 2Hz (550.3±89.7MPa), 10Hz (574.0±47MPa) and 20Hz (605.1±30.7MPa). Pearson correlation coefficient indicated a significantly moderate correlation (r=0.57) between fatigue strength and loading frequency. The percentage of monoclinic phase was similar among the groups. Therefore, the use of loading frequencies up to 20Hz seems a good alternative to expedite the cycling strength fatigue tests in polycrystalline ceramics without significantly changing the fatigue behavior showed by zirconia in tests employing the frequency of the masticatory cycle. PMID:26849030

  11. Loading frequencies up to 20Hz as an alternative to accelerate fatigue strength tests in a Y-TZP ceramic.

    PubMed

    Fraga, Sara; Pereira, Gabriel Kalil Rocha; Freitas, Mariana; Kleverlaan, Cornelis Johannes; Valandro, Luiz Felipe; May, Liliana Gressler

    2016-08-01

    Considering the interest of the research community in the fatigue behavior of all-ceramic restorations and the time consumed in low-frequency cyclic fatigue tests, this study aimed to investigate the influence of the loading frequency on the zirconia fatigue strength. The biaxial flexural fatigue strength of Y-TZP discs was determined by the staircase approach after 500,000 cycles. The investigated frequencies were 2Hz (control-simulation of the chewing activity; n=20), 10Hz (n=20), 20Hz (n=20), and 40Hz (n=21). The fatigue strength data were analyzed using one-way ANOVA and post-hoc Tukey׳s test (α=0.05). Pearson coefficient (r) was calculated to assess the existence of a correlation between fatigue strength and loading frequency. X-ray diffraction analysis was used to determine the relative amount of monoclinic phase under each fatigue test condition. The fatigue strength was significantly higher for 40Hz group (630.7±62.1MPa) and did not differ among the groups 2Hz (550.3±89.7MPa), 10Hz (574.0±47MPa) and 20Hz (605.1±30.7MPa). Pearson correlation coefficient indicated a significantly moderate correlation (r=0.57) between fatigue strength and loading frequency. The percentage of monoclinic phase was similar among the groups. Therefore, the use of loading frequencies up to 20Hz seems a good alternative to expedite the cycling strength fatigue tests in polycrystalline ceramics without significantly changing the fatigue behavior showed by zirconia in tests employing the frequency of the masticatory cycle.

  12. Comparison of the Effects of 1 Hz and 20 Hz rTMS on Motor Recovery in Subacute Stroke Patients

    PubMed Central

    Kim, Chul; Choi, Hee Eun; Lee, Byeong-Ju; Lee, Ki Hoon; Lim, Young-Joon

    2014-01-01

    Objective To compare the low frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) with high frequency (20 Hz) rTMS on motor functional improvement of the affected upper extremity in subacute stroke patients. Methods Forty patients with subacute ischemic stroke participated in this study. The first group received 10 sessions of 20 Hz rTMS at ipsilesional M1 area and the other group received 10 sessions of 1 Hz rTMS at contralesional M1 area. Motor training of the hemiparetic hand was conducted after each rTMS train. All the patients received conventional occupational therapy immediately after each rTMS session. Manual function test (MFT), Fugl-Meyer Assessment scale (FMS), Modified Barthel Index (MBI), Brunnstrom recovery stage, and grip strength were used to assess motor function before, at the end of, and one month after the last session of rTMS. Results No adverse side effects were reported during the course of the experiment using rTMS. No significant difference in motor function of the affected upper extremity was observed between the two groups before rTMS. Significant improvements in MFT, FMS, MBI, and Brunnstrom stage were observed in the both groups at the end of the last rTMS session and one month later (p<0.05). No significant difference was found between the two groups (p>0.05). Conclusion There was no significant difference in motor function of the affected upper extremity between 1 Hz and 20 Hz rTMS during the subacute period of ischemic stroke. Thus, we cannot conclude which has a greater effect. PMID:25379487

  13. Evaluation of the economic burden of Herpes Zoster (HZ) infection

    PubMed Central

    Panatto, Donatella; Bragazzi, Nicola Luigi; Rizzitelli, Emanuela; Bonanni, Paolo; Boccalini, Sara; Icardi, Giancarlo; Gasparini, Roberto; Amicizia, Daniela

    2014-01-01

    The main objective of this systematic review was to evaluate the economic burden of Herpes Zoster (HZ) infection. The review was conducted in accordance with the standards of the “Preferred Reporting Items for Systematic Reviews and Meta-Analyses” guidelines. The following databases were accessed: ISI/Web of Knowledge (WoS), MEDLINE/PubMed, Scopus, ProQuest, the Cochrane Library and EconLit. Specific literature on health economics was also manually inspected. Thirty-three studies were included. The quality of the studies assessed in accordance with the Consolidated Health Economic Evaluation Reporting Standards checklist was good. All studies evaluated direct costs, apart from one which dealt only with indirect costs. Indirect costs were evaluated by 12 studies. The economic burden of HZ has increased over time. HZ management and drug prescriptions generate the highest direct costs. While increasing age, co-morbidities and drug treatment were found to predict higher direct costs, being employed was correlated with higher indirect costs, and thus with the onset age of the disease. Despite some differences among the selected studies, particularly with regard to indirect costs, all concur that HZ is a widespread disease which has a heavy social and economic burden. PMID:25483704

  14. Evaluation of the economic burden of Herpes Zoster (HZ) infection.

    PubMed

    Panatto, Donatella; Bragazzi, Nicola Luigi; Rizzitelli, Emanuela; Bonanni, Paolo; Boccalini, Sara; Icardi, Giancarlo; Gasparini, Roberto; Amicizia, Daniela

    2015-01-01

    The main objective of this systematic review was to evaluate the economic burden of Herpes Zoster (HZ) infection.   The review was conducted in accordance with the standards of the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" guidelines. The following databases were accessed: ISI/Web of Knowledge (WoS), MEDLINE/PubMed, Scopus, ProQuest, the Cochrane Library and EconLit. Specific literature on health economics was also manually inspected. Thirty-three studies were included. The quality of the studies assessed in accordance with the Consolidated Health Economic Evaluation Reporting Standards checklist was good. All studies evaluated direct costs, apart from one which dealt only with indirect costs. Indirect costs were evaluated by 12 studies. The economic burden of HZ has increased over time. HZ management and drug prescriptions generate the highest direct costs. While increasing age, co-morbidities and drug treatment were found to predict higher direct costs, being employed was correlated with higher indirect costs, and thus with the onset age of the disease. Despite some differences among the selected studies, particularly with regard to indirect costs, all concur that HZ is a widespread disease which has a heavy social and economic burden.

  15. A 40-Hz Auditory Potential Recorded from the Human Scalp

    NASA Astrophysics Data System (ADS)

    Galambos, Robert; Makeig, Scott; Talmachoff, Peter J.

    1981-04-01

    Computer techniques readily extract from the brainwaves an orderly sequence of brain potentials locked in time to sound stimuli. The potentials that appear 8 to 80 msec after the stimulus resemble 3 or 4 cycles of a 40-Hz sine wave; we show here that these waves combine to form a single, stable, composite wave when the sounds are repeated at rates around 40 per sec. This phenomenon, the 40-Hz event-related potential (ERP), displays several properties of theoretical and practical interest. First, it reportedly disappears with surgical anesthesia, and it resembles similar phenomena in the visual and olfactory system, facts which suggest that adequate processing of sensory information may require cyclical brain events in the 30- to 50-Hz range. Second, latency and amplitude measurements on the 40-Hz ERP indicate it may contain useful information on the number and basilar membrane location of the auditory nerve fibers a given tone excites. Third, the response is present at sound intensities very close to normal adult thresholds for the audiometric frequencies, a fact that could have application in clinical hearing testing.

  16. 14 J/2 Hz Yb3+:YAG diode pumped solid state laser chain.

    PubMed

    Gonçalvès-Novo, Thierry; Albach, Daniel; Vincent, Bernard; Arzakantsyan, Mikayel; Chanteloup, Jean-Christophe

    2013-01-14

    The Lucia laser chain is a Diode Pumped Solid State Laser system based on Yb3+ doped YAG disks used in an active mirror scheme. Front-end and amplifier stages are presented with recent energetic performances (14 J/2 Hz) achieved with improved pumping and extraction architectures. Emphasis is given on the crucial role of ASE and thermal mitigation considerations in engineering the amplifier head. PMID:23388979

  17. Gamma (40-100 Hz) oscillation in the hippocampus of the behaving rat.

    PubMed

    Bragin, A; Jandó, G; Nádasdy, Z; Hetke, J; Wise, K; Buzsáki, G

    1995-01-01

    The cellular generation and spatial distribution of gamma frequency (40-100 Hz) activity was examined in the hippocampus of the awake rat. Field potentials and unit activity were recorded by multiple site silicon probes (5- and 16-site shanks) and wire electrode arrays. Gamma waves were highly coherent along the long axis of the dentate hilus, but average coherence decreased rapidly in the CA3 and CA1 directions. Analysis of short epochs revealed large fluctuations in coherence values between the dentate and CA1 gamma waves. Current source density analysis revealed large sinks and sources in the dentate gyrus with spatial distribution similar to the dipoles evoked by stimulation of the perforant path. The frequency changes of gamma and theta waves positively correlated (40-100 Hz and 5-10 Hz, respectively). Putative interneurons in the dentate gyrus discharged at gamma frequency and were phase-locked to the ascending part of the gamma waves recorded from the hilus. Following bilateral lesion of the entorhinal cortex the power and frequency of hilar gamma activity significantly decreased or disappeared. Instead, a large amplitude but slower gamma pattern (25-50 Hz) emerged in the CA3-CA1 network. We suggest that gamma oscillation emerges from an interaction between intrinsic oscillatory properties of interneurons and the network properties of the dentate gyrus. We also hypothesize that under physiological conditions the hilar gamma oscillation may be entrained by the entorhinal rhythm and that gamma oscillation in the CA3-CA1 circuitry is suppressed by either the hilar region or the entorhinal cortex.

  18. Separation of circadian and wake duration-dependent modulation of EEG activation during wakefulness

    NASA Technical Reports Server (NTRS)

    Cajochen, C.; Wyatt, J. K.; Czeisler, C. A.; Dijk, D. J.

    2002-01-01

    The separate contribution of circadian rhythmicity and elapsed time awake on electroencephalographic (EEG) activity during wakefulness was assessed. Seven men lived in an environmental scheduling facility for 4 weeks and completed fourteen 42.85-h 'days', each consisting of an extended (28.57-h) wake episode and a 14.28-h sleep opportunity. The circadian rhythm of plasma melatonin desynchronized from the 42.85-h day. This allowed quantification of the separate contribution of circadian phase and elapsed time awake to variation in EEG power spectra (1-32 Hz). EEG activity during standardized behavioral conditions was markedly affected by both circadian phase and elapsed time awake in an EEG frequency- and derivation-specific manner. The nadir of the circadian rhythm in alpha (8-12 Hz) activity in both fronto-central and occipito-parietal derivations occurred during the biological night, close to the crest of the melatonin rhythm. The nadir of the circadian rhythm of theta (4.5-8 Hz) and beta (20-32 Hz) activity in the fronto-central derivation was located close to the onset of melatonin secretion, i.e. during the wake maintenance zone. As time awake progressed, delta frequency (1-4.5 Hz) and beta (20-32 Hz) activity rose monotonically in frontal derivations. The interaction between the circadian and wake-dependent increase in frontal delta was such that the intrusion of delta was minimal when sustained wakefulness coincided with the biological day, but pronounced during the biological night. Our data imply that the circadian pacemaker facilitates frontal EEG activation during the wake maintenance zone, by generating an arousal signal that prevents the intrusion of low-frequency EEG components, the propensity for which increases progressively during wakefulness.

  19. Humans perceive flicker artifacts at 500 Hz.

    PubMed

    Davis, James; Hsieh, Yi-Hsuan; Lee, Hung-Chi

    2015-02-03

    Humans perceive a stable average intensity image without flicker artifacts when a television or monitor updates at a sufficiently fast rate. This rate, known as the critical flicker fusion rate, has been studied for both spatially uniform lights, and spatio-temporal displays. These studies have included both stabilized and unstablized retinal images, and report the maximum observable rate as 50-90 Hz. A separate line of research has reported that fast eye movements known as saccades allow simple modulated LEDs to be observed at very high rates. Here we show that humans perceive visual flicker artifacts at rates over 500 Hz when a display includes high frequency spatial edges. This rate is many times higher than previously reported. As a result, modern display designs which use complex spatio-temporal coding need to update much faster than conventional TVs, which traditionally presented a simple sequence of natural images.

  20. 600-Hz linewidth short-linear-cavity fiber laser.

    PubMed

    Mo, Shupei; Huang, Xiang; Xu, Shanhui; Li, Can; Yang, Changsheng; Feng, Zhouming; Zhang, Weinan; Chen, Dongdan; Yang, Zhongmin

    2014-10-15

    We proposed a short-linear-cavity (SLC) fiber laser based on a virtual-folded-ring (VFR) resonator and a fiber Bragg grating Fabry-Perot filter. Spatial hole burning effect was reduced by retarding the polarization state of the counter-propagating light waves utilizing the VFR structure. The photon lifetime of the resonator was extended due to the multi-reflection inside the FBG FP, which increased the intra-cavity power and relatively suppressed the contribution of phase diffusion from spontaneous emission. The relaxation oscillation frequency is around 160 kHz due to the slow light effect. The linewidth of the SLC fiber laser was measured to be less than 600 Hz.

  1. Algebra: Grades 8-12.

    ERIC Educational Resources Information Center

    Instructional Objectives Exchange, Los Angeles, CA.

    A complete set of behavioral objectives for first-year algebra taught in any of grades 8 through 12 is presented. Three to six sample test items and answers are provided for each objective. Objectives were determined by surveying the most used secondary school algebra textbooks. Fourteen major categories are included: (1) whole numbers--operations…

  2. Neocortical very fast oscillations (ripples, 80-200 Hz) during seizures: intracellular correlates.

    PubMed

    Grenier, François; Timofeev, Igor; Steriade, Mircea

    2003-02-01

    Multi-site field potential and intracellular recordings from various neocortical areas were used to study very fast oscillations or ripples (80-200 Hz) during electrographic seizures in cats under ketamine-xylazine anesthesia. The animals displayed spontaneously occurring and electrically induced seizures comprising spike-wave complexes (2-3 Hz) and fast runs (10-20 Hz). Neocortical ripples had much higher amplitudes during seizures than during the slow oscillation preceding the onset of seizures. A series of experimental data from the present study supports the hypothesis that ripples are implicated in seizure initiation. Ripples were particularly strong at the onset of seizures and halothane, which antagonizes the occurrence of ripples, also blocked seizures. The firing of electrophysiologically defined cellular types was phase-locked with ripples in simultaneously recorded field potentials. This indicates that ripples during paroxysmal events are associated with a coordination of firing in a majority of neocortical neurons. This was confirmed with dual intracellular recordings. Based on the amplitude that neocortical ripples reach during paroxysmal events, we propose a mechanism by which neocortical ripples during normal network activity could actively participate in the initiation of seizures on reaching a certain threshold amplitude. This mechanism involves a vicious feedback loop in which very fast oscillations in field potentials are a reflection of synchronous action potentials, and in turn these oscillations help generate and synchronize action potentials in adjacent neurons through electrical interactions.

  3. Somatotopic source arrangement of 600 Hz oscillatory magnetic fields at the human primary somatosensory hand cortex.

    PubMed

    Curio, G; Mackert, B M; Burghoff, M; Neumann, J; Nolte, G; Scherg, M; Marx, P

    1997-10-01

    Based on low-noise superconducting quantum interference devices (SQUIDs) magnetoencephalography allows the non-invasive detection of low-amplitude high-frequency brain responses evoked about 20 ms after electric hand nerve stimulation. The main spectral energy of these brief oscillatory bursts (near 600 Hz) is in the range typical for rapidly repeated action potentials. Here, the magnetic fields of median and ulnar nerve evoked 600 Hz bursts are shown to exhibit a somatotopic arrangement at the primary somatosensory hand cortex closely resembling that of the concomitant postsynaptic primary cortical response (¿N20m'). Two possible burst generators are discussed: (1) repetitive spike volleys conducted along the terminal segments of somatotopically arranged thalamocortical axons, and (2) early intracortical spike activity in nerve-specific subterritories of the 3b hand area.

  4. Matrix metalloproteinases -1, -2, -3, -7, -8, -12, and -13 in gingival crevicular fluid during orthodontic tooth movement: a longitudinal randomized split-mouth study.

    PubMed

    Canavarro, Cristiane; Teles, Ricardo Palmier; Capelli Júnior, Jonas

    2013-10-01

    This randomized split-mouth study aimed to examine the levels of matrix metalloproteinases (MMPs) -1, -2, -3, -7, -8, -12, and -13 in the gingival crevicular fluid (GCF) at different time points during orthodontic tooth movement. A total of 16 healthy orthodontic subjects (7 females, 9 males; mean age, 17.7 years) who needed their first upper premolars extracted were enrolled. One randomly chosen maxillary canine was subjected to a distalizing force and was considered to be the test side. The contralateral canine, which was not subjected to any force but was included in the orthodontic appliance, was used as a control side. GCF sampling was performed at both the mesial (tension) and distal (pressure) test and control sites at baseline, immediately before applying the orthodontic appliance, and after 1 and 24 hours and 7, 14, and 21 days. A multiplexed bead immunoassay was used to analyse the GCF samples. The mean levels of the MMP-1, -2, -3, -7, -8, -12, and -13 were not significantly different between the test and control groups in each time showed. The comparisons between the tension and pressure sites were also not significantly different at each individual time. A few variations focused on MMP-1 and -3, but the expression of MMP-8 was higher than that of the other MMPs. MMPs are released in sufficient quantities such that tooth movement occurs but with no significant increase in GCF levels.

  5. Improvements in GPS precision: 10 Hz to one day

    NASA Astrophysics Data System (ADS)

    Choi, Kyuhong

    Seeking to understand Global Positioning System (GPS) measurements and the positioning solutions in various time intervals, this dissertation improves the consistency of pseudorange measurements from different receiver types, processes 30 s interval data with optimized filtering techniques, and analyzes very-high-rate data with short arc lengths and baseline noise. The first project studies satellite-dependent biases between C/A and P1 codes. Calibrating these biases reduces the inconsistency of satellite clocks, improving the ambiguity resolution which allows for higher position precision. Receiver-dependent biases for two receivers are compared with the bias products of Center for Orbit Determination in Europe (CODE). Baseline lengths ranging up to ˜2,100km are tested with the receiver-specific biases; they resolve more phase ambiguity by 4.3% than using CODE's products. The second project analyzes 1 s and 30 s interval GPS data of the 2003 Tokachi-Oki earthquake. For 1 Hz positioning, Iterative Tropospheric Estimation (ITE) method improves vertical precision. While equalized sidereal filtering reduces noise for multipath-dominant 30--300 s periods, it can cause long-term drifts in the timeseries. A study of postseismic deformation after the Tokachi-Oki earthquake uses 30 s interval position estimations to test multiple filtering strategies to maximize precision using lower-rate data. On top of the residual stacking, estimation of a random walk constraint of sigmaDelta = 1.80 cm/ hr shows maximum noise reduction capability while retaining the real deformation signal. These techniques enhance our grasp of fault response in the aftermath of great earthquakes. The third project probes noise floor characteristics of very-high-rate (> 1 Hz) GPS data. A hybrid method, designed and tested to resolve phase biases, minimizes computational burdens while keeping the quality of ambiguity-fixed solutions. Noise characteristics are compared after an analysis of 5 and 10 Hz

  6. Characterization of the transcriptome of Achromobacter sp. HZ01 with the outstanding hydrocarbon-degrading ability.

    PubMed

    Hong, Yue-Hui; Deng, Mao-Cheng; Xu, Xiao-Ming; Wu, Chou-Fei; Xiao, Xi; Zhu, Qing; Sun, Xian-Xian; Zhou, Qian-Zhi; Peng, Juan; Yuan, Jian-Ping; Wang, Jiang-Hai

    2016-06-15

    Microbial remediation has become one of the most important strategies for eliminating petroleum pollutants. Revealing the transcript maps of microorganisms with the hydrocarbon-degrading ability contributes to enhance the degradation of hydrocarbons and further improve the effectiveness of bioremediation. In this study, we characterized the transcriptome of hydrocarbon-degrading Achromobacter sp. HZ01 after petroleum treatment for 16h. A total of 38,706,280 and 38,954,413 clean reads were obtained by RNA-seq for the petroleum-treated group and control, respectively. By an effective de novo assembly, 3597 unigenes were obtained, including 3485 annotated transcripts. Petroleum treatment had significantly influenced the transcriptional profile of strain HZ01, involving 742 differentially expressed genes. A part of genes were activated to exert specific physiological functions, whereas more genes were down-regulated including specific genes related to cell motility, genes associated with glycometabolism, and genes coding for ribosomal proteins. Identification of genes related to petroleum degradation revealed that the fatty acid metabolic pathway and a part of monooxygenases and dehydrogenases were activated, whereas the TCA cycle was inactive. Additionally, terminal oxidation might be a major aerobic pathway for the degradation of n-alkanes in strain HZ01. The newly obtained data contribute to better understand the gene expression profiles of hydrocarbon-degrading microorganisms after petroleum treatment, to further investigate the genetic characteristics of strain HZ01 and other related species and to develop cost-effective and eco-friendly strategies for remediation of crude oil-polluted environments.

  7. Splitting attention reduces temporal resolution from 7 Hz for tracking one object to <3 Hz when tracking three.

    PubMed

    Holcombe, Alex O; Chen, Wei-Ying

    2013-01-01

    Overall performance when tracking moving targets is known to be poorer for larger numbers of targets, but the specific effect on tracking's temporal resolution has never been investigated. We document a broad range of display parameters for which visual tracking is limited by temporal frequency (the interval between when a target is at each location and a distracter moves in and replaces it) rather than by object speed. We tested tracking of one, two, and three moving targets while the eyes remained fixed. Variation of the number of distracters and their speed revealed both speed limits and temporal frequency limits on tracking. The temporal frequency limit fell from 7 Hz with one target to 4 Hz with two targets and 2.6 Hz with three targets. The large size of this performance decrease implies that in the two-target condition participants would have done better by tracking only one of the two targets and ignoring the other. These effects are predicted by serial models involving a single tracking focus that must switch among the targets, sampling the position of only one target at a time. If parallel processing theories are to explain why dividing the tracking resource reduces temporal resolution so markedly, supplemental assumptions will be required.

  8. Atmospheric Electric Field Measurements at 100 Hz and High Frequency Electric Phenomena

    NASA Astrophysics Data System (ADS)

    Conceição, Ricardo; Gonçalves da Silva, Hugo; Matthews, James; Bennett, Alec; Chubb, John

    2016-04-01

    Spectral response of Atmospheric Electric Potential Gradient (PG), symmetric to the Atmospheric Electric Field, gives important information about phenomena affecting these measurements with characteristic time-scales that appear in the spectra as specific periodicities. This is the case of urban pollution that has a clear weekly dependence and reveals itself on PG measurements by a ~7 day periodicity (Silva et al., 2014). While long-term time-scales (low frequencies) have been exhaustively explored in literature, short-term time-scales (high frequencies), above 1 Hz, have comparatively received much less attention (Anisimov et al., 1999). This is mainly because of the technical difficulties related with the storage of such a huge amount of data (for 100 Hz sampling two days of data uses a ~1 Gb file) and the response degradation of the field-meters at such frequencies. Nevertheless, important Electric Phenomena occurs for frequencies above 1 Hz that are worth pursuing, e.g. the Schumann Resonances have a signature of worldwide thunderstorm activity at frequencies that go from ~8 up to ~40 Hz. To that end the present work shows preliminary results on PG measurements at 100 Hz that took place on two clear-sky days (17th and 18th June 2015) on the South of Portugal, Évora (38.50° N, 7.91° W). The field-mill used is a JCI 131F installed in the University of Évora campus (at 2 m height) with a few trees and two buildings in its surroundings (~50 m away). This device was developed by John Chubb (Chubb, 2014) and manufactured by Chilworth (UK). It was calibrated in December 2013 and recent work by the author (who is honored in this study for his overwhelming contribution to atmospheric electricity) reveals basically a flat spectral response of the device up to frequencies of 100 Hz (Chubb, 2015). This makes this device suitable for the study of High Frequency Electric Phenomena. Anisimov, S.V., et al. (1999). On the generation and evolution of aeroelectric structures

  9. Using bedding in a test environment critically affects 50-kHz ultrasonic vocalizations in laboratory rats.

    PubMed

    Natusch, C; Schwarting, R K W

    2010-09-01

    Rats utter distinct classes of ultrasonic vocalizations depending on their developmental stage, current state, and situational factors. One class, comprising the so-called 50-kHz calls, is typical for situations where rats are anticipating or actually experiencing rewarding stimuli, like being tickled by an experimenter, or when treated with drugs of abuse, such as the psychostimulant amphetamine. Furthermore, rats emit 50-kHz calls when exposed to a clean housing cage. Here, we show that such vocalization effects can depend on subtle details of the testing situation, namely the presence of fresh rodent bedding. Actually, we found that adult males vocalize more in bedded cages than in bare ones. Also, two experiments showed that adult rats emitted more 50-kHz calls when tickled on fresh bedding. Furthermore, ip amphetamine led to more 50-kHz vocalization in activity boxes containing such bedding as compared to bare ones. The analysis of psychomotor activation did not yield such group differences in case of locomotion and centre time, except for rearing duration in rats tested on bedding. Also, the temporal profile of vocalization did not parallel that of behavioural activation, since the effects on vocalization peaked and started to decline again before those of psychomotor activation. Therefore, 50-kHz calls are not a simple correlate of psychomotor activation. A final experiment with a choice procedure showed that rats prefer bedded conditions. Overall, we assume that bedded environments induce a positive affective state, which increases the likelihood of 50-kHz calling. Based on these findings, we recommend that contextual factors, like bedding, should receive more research attention, since they can apparently decrease the aversiveness of a testing situation. Also, we recommend to more routinely measure rat ultrasonic vocalization, especially when studying emotion and motivation, since this analysis can provide information about the subject's status, which may

  10. Design and performance of a 250 Hz alexandrite laser

    SciTech Connect

    Sam, R.C.; Yeh, J.J.; Leslie, K.R.; Rapoport, W.R.

    1988-06-01

    The design, analysis, and performance of a 250 Hz alexandrite laser are described. Built as the wavelength selective laser for a molecular laser isotope separation program, the laser has to satisfy specifications on its tuning band, linewidth, output energy, temporal behavior, and repetition rate required by the process. The key design feature is the use of a tandem rod oscillator with concave curvature on rod ends for thermal lensing compensation. A model was developed to project the stability range and beam quality relative to repetition rate. The performance results of a delivered system are presented and future developments are discussed.

  11. The 2.2 Hz oscillations in auroral electrons

    NASA Astrophysics Data System (ADS)

    Lepine, D. R.; Hall, D. S.; Bryant, D. A.; Johnstone, A. D.; Christiansen, P. J.; Gough, M. P.

    1980-06-01

    A Petrel rocket was launched from Kiruna on 25 January 1979 to compare electron intensities measured at auroral altitudes with related parameters measured at geostationary altitude by the satellite GEOS 2. A sequence of quasi-periodic oscillations in electron intensities were investigated, which appear to originate in the equatorial region, probably in the neighborhood of GEOS 2 was investigated. A similar frequency oscillation in the intensity of 500-Hz VLF emissions was observed at about the same time by the S300 wave experiment located on the satellite.

  12. 1-kHz-repetition-rate femtosecond Raman laser

    NASA Astrophysics Data System (ADS)

    Didenko, N. V.; Konyashchenko, A. V.; Kostryukov, P. V.; Losev, L. L.; Pazyuk, V. S.; Tenyakov, S. Yu

    2016-07-01

    A femtosecond Raman laser utilising compressed hydrogen is experimentally investigated under pumping by radiation from a 1-kHz-repetition-rate Ti : sapphire laser. In the regime of double-pulse pumping, the conditions are determined, which correspond to the minimal energy dispersion of Stokes pulses. The optical scheme is realised, which is capable of ensuring the long-term stability of the average power of the first Stokes component with a variation of less than 2%. The Stokes pulses are produced with a pulse duration of 60 fs and energy of 0.26 mJ at a conversion efficiency of 14%.

  13. Alpha power and coherence primarily reflect neural activity related to stages of motor response during a continuous monitoring task.

    PubMed

    Moore, Roger A; Gale, Anthony; Morris, Paul H; Forrester, Dave

    2008-08-01

    Previously, EEG theta (4-6 Hz) was related to goal conflict resolution [Moore, R.A., Gale, A., Morris, P.H., Forrester, D., 2006. Theta phase locking across the neocortex reflects cortico-hippocampal recursive communication during goal conflict resolution. Int. J. Psychophysiol. 60, 260-273] in the context of theory linked with animal hippocampal theta [Gray, J.A., McNaughton, N., 2000. The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-Hippocampal system, 2nd ed, Oxford University Press, Oxford]. Here, the hypothesis that human EEG alpha (8-12 Hz) may also be a natural analogue to animal hippocampal theta is tested. Participants engaged in a monitoring task where the object was to press a response key immediately after presentation of 4 individual, non-repeating, single integer odd digits. These were presented amongst a continuous stream of single integer digits and Xs. EEG recorded in the earlier study were reanalysed; this time extracting alpha power and coherence from the same 34 participants. Alpha had a different profile to theta and was not primarily related to goal conflict. Low alpha (8-10 Hz) coherence consistently increased at electrodes close to primary sensorimotor cortex; particularly during response execution and response inhibition. The coherence analysis revealed that high alpha (10-12 Hz) related to response execution. Supplementary analyses demonstrated widespread high alpha coherence increase during response execution, inhibition and preparation. These data were discussed within the context of motor driven 'classic alpha' and Rolandic mu. A coherence profile which differentiated response execution and response inhibition was proposed to reflect a working memory network which was activated during response execution. Also, alpha power (8-12 Hz) reduced at several central electrodes during response execution. This reflected classic Rolandic mu response. Participants displaying a predicted low alpha power trend had the

  14. 4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo[5.5.0.05,903,11]dodecane Synthesis

    NASA Astrophysics Data System (ADS)

    Maksimowski, Paweł; Gołofit, Tomasz

    2013-07-01

    4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo[5.5.0.05,903,11]dodecane (TEX) was obtained by nitrolysis of 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine reaction using a mixture of fuming nitric acid and concentrated sulfuric acid. The optimal process temperature was 54-56°C. The yield of the synthesis depends inter alia on the rate the reactants are introduced into the reaction medium and on the time of conditioning of the reaction mixture. A maximal yield of ca. 40% was achieved at the reactant addition time of 2 h and conditioning time of 2 h. None of the other nitrating mixtures examined proved superior to the conventional nitrating mixture. The product was examined by high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), and differential scanning calorimetry (DSC) techniques and the results are reported.

  15. Slip-stacking Dynamics and the 20 Hz Booster

    SciTech Connect

    Eldred, Jeffery; Zwaska, Robert

    2015-03-01

    Slip-stacking is an accumulation technique used at Fermilab since 2004 which nearly doubles the proton intensity. The Proton Improvement Plan II intensity upgrades require a reduction in slip-stacking losses by approximately a factor of 2. We study the single-particle dynamics that determine the stability of slip-stacking particles. We introduce universal area factors to calculate the available phase space area for any set of beam parameters without individual simulation. We show the particle loss as a function of time. We calculate the injection efficiency as a function of longitudinal emittance and aspect-ratio. We demonstrate that the losses from RF single particle dynamics can be reduced by a factor of 4-10 (depending on beam parameters) by upgrading the Fermilab Booster from a 15-Hz cycle-rate to a 20-Hz cycle-rate. We recommend a change in injection scheme to eliminate the need for a greater momentum aperture in the Fermilab Recycler.

  16. Endocrinological effects of strong 60-Hz electric fields on rats

    SciTech Connect

    Free, M.J.; Kaune, W.T.; Phillips, R.D.; Cheng, H.C.

    1981-01-01

    Adult male rats were exposed or sham-exposed to 60-Hz electric fields without spark discharges, ozone, or significant levels or other secondary variables. No effects were discharges, ozone, or significant levels of other secondary variables. No effects were observed on body weights or plasma hormone levels after 30 days of exposure at an effective field strength of 68 kV/m. After 120 days of exposure (effective field strength = 64 kV/m), effects were inconsistent, with signficant reductions in body weight and plasma levels of follicle-stimulating hormone and corticosterone occurring in one replicate experiment but not in the other. Plasma testosterone levels were significantly reduced after 120 days of exposure in one experiment, with a similar but not statistically significant reduction in a replicate experiment. Weanling rats, exposed or sham-exposed in electric fields with an effective field strength of 80 kV/m from 20 to 56 days of age, exhibited identical or closely similar growth trends in body and organ weights. Hormone levels in exposed and sham-exposed groups were also similar. However, there was an apparent phase shift between the two groups in the cyclic variations of concentrations of hormones at different stages of development, particularly with respect to follicle-stimulating hormone and corticosterone. We concluded that 60-Hz electric fields may bring about subtle changes in the endocrine system of rats, and that these changes may be related to alterations in episodic rhythms.

  17. The Effect of 10 Hz Repetitive Transcranial Magnetic Stimulation of Posterior Parietal Cortex on Visual Attention

    PubMed Central

    Dombrowe, Isabel; Juravle, Georgiana; Alavash, Mohsen; Gießing, Carsten; Hilgetag, Claus C.

    2015-01-01

    Repetitive transcranial magnetic stimulation (rTMS) of the posterior parietal cortex (PPC) at frequencies lower than 5 Hz transiently inhibits the stimulated area. In healthy participants, such a protocol can induce a transient attentional bias to the visual hemifield ipsilateral to the stimulated hemisphere. This bias might be due to a relatively less active stimulated hemisphere and a relatively more active unstimulated hemisphere. In a previous study, Jin and Hilgetag (2008) tried to switch the attention bias from the hemifield ipsilateral to the hemifield contralateral to the stimulated hemisphere by applying high frequency rTMS. High frequency rTMS has been shown to excite, rather than inhibit, the stimulated brain area. However, the bias to the ipsilateral hemifield was still present. The participants’ performance decreased when stimuli were presented in the hemifield contralateral to the stimulation site. In the present study we tested if this unexpected result was related to the fact that participants were passively resting during stimulation rather than performing a task. Using a fully crossed factorial design, we compared the effects of high frequency rTMS applied during a visual detection task and high frequency rTMS during passive rest on the subsequent offline performance in the same detection task. Our results were mixed. After sham stimulation, performance was better after rest than after task. After active 10 Hz rTMS, participants’ performance was overall better after task than after rest. However, this effect did not reach statistical significance. The comparison of performance after rTMS with task and performance after sham stimulation with task showed that 10 Hz stimulation significantly improved performance in the whole visual field. Thus, although we found a trend to better performance after rTMS with task than after rTMS during rest, we could not reject the hypothesis that high frequency rTMS with task and high frequency rTMS during rest

  18. Acute effects of aerobic stretching, health and happiness improving movement exercise on cortical activity of children.

    PubMed

    Choi, Hyungsoo; Park, Sangjun; Kim, Kyekyoon Kevin; Lee, Kwanghee; Rhyu, Hyun-Seung

    2016-08-01

    Acute high-intensity physical exercise is known to improve cognitive performance of children, including those with attention-deficit/hyperactivity disorder (ADHD). In this work, we investigated the acute effect of an aerobic stretching and moderate-intensity, health and happiness improving movement (HHIM) exercise on the cortical activity of children with and without ADHD using electroencephalography (EEG). Children aged 12 to 14 yr with combined-type ADHD and age-matched healthy controls participated in the study, performing two individual movements (n=79, 35 controls) and a single exercise bout (n=45, 18 controls). electroencephalographic signals were recorded before and immediately after each movement, and before and after acute exercise under resting conditions, to obtain absolute and relative power estimates for the theta (3.5-8 Hz), alpha (8-12 Hz), sensory motor rhythm (12-16 Hz), and beta (16-25 Hz) bands. After acute HHIM exercise, all children showed significant changes in their relative EEG, mainly in the theta and alpha bands. Individual movements were found to influence relative theta, alpha and beta, and theta-to-beta ratios. He presents aerobic stretching HHIM exercise has demonstrated acute effect on the cortical activity of children.

  19. Acute effects of aerobic stretching, health and happiness improving movement exercise on cortical activity of children.

    PubMed

    Choi, Hyungsoo; Park, Sangjun; Kim, Kyekyoon Kevin; Lee, Kwanghee; Rhyu, Hyun-Seung

    2016-08-01

    Acute high-intensity physical exercise is known to improve cognitive performance of children, including those with attention-deficit/hyperactivity disorder (ADHD). In this work, we investigated the acute effect of an aerobic stretching and moderate-intensity, health and happiness improving movement (HHIM) exercise on the cortical activity of children with and without ADHD using electroencephalography (EEG). Children aged 12 to 14 yr with combined-type ADHD and age-matched healthy controls participated in the study, performing two individual movements (n=79, 35 controls) and a single exercise bout (n=45, 18 controls). electroencephalographic signals were recorded before and immediately after each movement, and before and after acute exercise under resting conditions, to obtain absolute and relative power estimates for the theta (3.5-8 Hz), alpha (8-12 Hz), sensory motor rhythm (12-16 Hz), and beta (16-25 Hz) bands. After acute HHIM exercise, all children showed significant changes in their relative EEG, mainly in the theta and alpha bands. Individual movements were found to influence relative theta, alpha and beta, and theta-to-beta ratios. He presents aerobic stretching HHIM exercise has demonstrated acute effect on the cortical activity of children. PMID:27656629

  20. The global distribution of natural and man-made ionospheric electric fields at 200 kHz and 540 kHz as observed by Ogo 6

    NASA Technical Reports Server (NTRS)

    Laaspere, T.; Semprebon, L. C.

    1974-01-01

    An experiment on the polar-orbiting Ogo 6 spacecraft yielded real-time analog data in several broadband channels and essentially continuous tape-recorded data from two narrow-band (200-Hz) receivers operating at 200 and 540 kHz. The results show that the worldwide distributions of signals at 200 and 540 kHz falls into a number of different categories: (1) naturally generated broadband (auroral) hiss at polar latitudes with typical 200-kHz intensities of around 0.1 microvolt per meter per Hz to the 1/2 power, maximum intensities of up to several microvolt per meter per Hz to the 1/2 power, and generally lower intensities at 540 kHz; (2) nighttime midlatitude enhancements of a few microvolts per meter, which probably result either from a superposition of signals from a number of 200- and 540-kHz stations or from interference from intense signals of much higher frequencies; (3) well-defined signal peaks associated with individual ground stations operating at 200 kHz; (4) striking signal enhancements in the conjugate region of a low-latitude 200-kHz station (Ashkhabad), suggesting propagation in the whistler mode to the opposite hemisphere; and (5) occasional signal enhancements at the magnetic equator.

  1. 60-Hz electric-field effects on pineal melatonin rhythms: time course for onset and recovery

    SciTech Connect

    Wilson, B.W.; Chess, E.K.; Anderson, L.E.

    1986-01-01

    Rats exposed for 3 weeks to uniform 60-Hz electric fields of 39 kV/m (effective field strength) failed to show normal pineal gland circadian rhythms in serotonin N-acetyl transferase activity and melatonin concentrations. The time required for recovery of the melatonin rhythm after cessation of field exposure was determined to be less than 3 days. The rapid recovery suggests that the overall metabolic competence of the pineal is not permanently compromised by electric-field exposure, and that the circadian rhythm effect may be neuronally mediated.

  2. 100 kHz Mueller polarimeter in reflection configuration.

    PubMed

    Le Gratiet, Aymeric; Rivet, Sylvain; Dubreuil, Matthieu; Le Grand, Yann

    2015-02-15

    A new setup is proposed to perform high-speed Mueller polarimetry by spectral coding of polarization in a reflection configuration. The system uses a swept laser source and a photodiode, which results in a simple optical setup that allows measurement of Mueller matrices at 100 kHz repetition rate. A special focus is made on the influence of the cube beam splitter polarimetric response, which is essential to measurements in a reflection configuration. The instrument is first validated on reference samples for single-point measurements, and the effect of a proper system calibration is also demonstrated on polarimetric images. The device is intended to be implemented within a laser scanning microscope to perform multimodal imaging (confocal/multiphoton and Mueller polarimetry). PMID:25680171

  3. Influence of 60-Hz magnetic fields on sea urchin development

    SciTech Connect

    Zimmerman, S.; Zimmerman, A.M.; Winters, W.D.; Cameron, I.L. )

    1990-01-01

    Continuous exposure of sea urchin (Strongylocentrotus purpuratus) embryos at 18 degrees C to a cyclic 60-Hz magnetic field at 0.1 mT rms beginning 4 min after insemination caused a significant developmental delay during the subsequent 23 hours. No delay in development was recorded for periods up to 18 hours after fertilization. At 18 h, most embryos were in the mesenchyme blastula stage. At 23 h, most control embryos were in mid-gastrula whereas most magnetic-field-exposed embryos were in the early gastrula stage. Thus an estimated 1-h delay occurred between these developmental stages. The results are discussed in terms of possible magnetic-field modification of transcription as well as interference with cell migration during gastrulation. The present study extends and supports the growing body of information about potential effects of exposures to extremely-low-frequency (ELF) magnetic fields on developing organisms.

  4. Investigation on Two-Stage 300 HZ Pulse Tube Cryocooler

    NASA Astrophysics Data System (ADS)

    Cai, H. K.; Yang, L. W.; Hong, G. T.; Luo, E. C.; Zhou, Y.

    2010-04-01

    In the past few years, ultra-high frequency pulse tube cryocoolers are becoming a research hotspot for their portability and compactness in aerospace and aviation applications. For preliminary research, a two-stage pulse tube cryocooler working at 300 Hz driven by a thermoacoustic engine is established to investigate the problems due to ultra high frequency, and several results have been derived in our early reports. In order to study the effect of thermal penetration depth, this paper presents the cooler adopting copper mesh as the regenerator, and comparison with stainless steel mesh is given. In addition, the influence of inertance tube on the lowest possible cooler temperature is also tested. Finally, we discuss the improvement for getting a lower temperature.

  5. EV drivetrain inverter with V/HZ optimization

    DOEpatents

    Gritter, David J.; O'Neil, Walter K.

    1986-01-01

    An inverter (34) which provides power to an A.C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A.C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A.C. machine is optimized. The control circuit includes a micro-computer which calculates optimized machine control data signals from various parametric inputs and during steady state load conditions, seeks a best V/HZ ratio to minimize battery current drawn (system losses) from a D.C. power source (32). In the preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack and a three-phase induction motor (18).

  6. Neocortical 40 Hz oscillations during carbachol-induced rapid eye movement sleep and cataplexy.

    PubMed

    Torterolo, Pablo; Castro-Zaballa, Santiago; Cavelli, Matías; Chase, Michael H; Falconi, Atilio

    2016-02-01

    Higher cognitive functions require the integration and coordination of large populations of neurons in cortical and subcortical regions. Oscillations in the gamma band (30-45 Hz) of the electroencephalogram (EEG) have been involved in these cognitive functions. In previous studies, we analysed the extent of functional connectivity between cortical areas employing the 'mean squared coherence' analysis of the EEG gamma band. We demonstrated that gamma coherence is maximal during alert wakefulness and is almost absent during rapid eye movement (REM) sleep. The nucleus pontis oralis (NPO) is critical for REM sleep generation. The NPO is considered to exert executive control over the initiation and maintenance of REM sleep. In the cat, depending on the previous state of the animal, a single microinjection of carbachol (a cholinergic agonist) into the NPO can produce either REM sleep [REM sleep induced by carbachol (REMc)] or a waking state with muscle atonia, i.e. cataplexy [cataplexy induced by carbachol (CA)]. In the present study, in cats that were implanted with electrodes in different cortical areas to record polysomnographic activity, we compared the degree of gamma (30-45 Hz) coherence during REMc, CA and naturally-occurring behavioural states. Gamma coherence was maximal during CA and alert wakefulness. In contrast, gamma coherence was almost absent during REMc as in naturally-occurring REM sleep. We conclude that, in spite of the presence of somatic muscle paralysis, there are remarkable differences in cortical activity between REMc and CA, which confirm that EEG gamma (≈40 Hz) coherence is a trait that differentiates wakefulness from REM sleep. PMID:26670051

  7. Neocortical 40 Hz oscillations during carbachol-induced rapid eye movement sleep and cataplexy.

    PubMed

    Torterolo, Pablo; Castro-Zaballa, Santiago; Cavelli, Matías; Chase, Michael H; Falconi, Atilio

    2016-02-01

    Higher cognitive functions require the integration and coordination of large populations of neurons in cortical and subcortical regions. Oscillations in the gamma band (30-45 Hz) of the electroencephalogram (EEG) have been involved in these cognitive functions. In previous studies, we analysed the extent of functional connectivity between cortical areas employing the 'mean squared coherence' analysis of the EEG gamma band. We demonstrated that gamma coherence is maximal during alert wakefulness and is almost absent during rapid eye movement (REM) sleep. The nucleus pontis oralis (NPO) is critical for REM sleep generation. The NPO is considered to exert executive control over the initiation and maintenance of REM sleep. In the cat, depending on the previous state of the animal, a single microinjection of carbachol (a cholinergic agonist) into the NPO can produce either REM sleep [REM sleep induced by carbachol (REMc)] or a waking state with muscle atonia, i.e. cataplexy [cataplexy induced by carbachol (CA)]. In the present study, in cats that were implanted with electrodes in different cortical areas to record polysomnographic activity, we compared the degree of gamma (30-45 Hz) coherence during REMc, CA and naturally-occurring behavioural states. Gamma coherence was maximal during CA and alert wakefulness. In contrast, gamma coherence was almost absent during REMc as in naturally-occurring REM sleep. We conclude that, in spite of the presence of somatic muscle paralysis, there are remarkable differences in cortical activity between REMc and CA, which confirm that EEG gamma (≈40 Hz) coherence is a trait that differentiates wakefulness from REM sleep.

  8. Copper bromide vapor brightness amplifiers with 100 kHz pulse repetition frequency

    NASA Astrophysics Data System (ADS)

    Trigub, M. V.; Evtushenko, G. S.; Torgaev, S. N.; Shiyanov, D. V.; Evtushenko, T. G.

    2016-10-01

    The paper presents a laser monitor with 10 μs time-resolution based on a high-frequency copper bromide vapor brightness amplifier. A sync circuit has been designed for single-pulse imaging. The analysis of amplifying characteristics of the active elements and active optical system (laser monitor) parameters allowed to determine the optimal concentration of HBr at which the images can be obtained with minimum distortions. For the active element operating at high frequencies (more than 50 kHz) as a brightness amplifier, the concentration of HBr must be lower than that needed for obtaining the maximum output power. The limiting brightness temperature of the background radiation which does not affect the image quality is determined. The potential feasibility of using a proposed brightness amplifier for visualizing processes blocked from viewing by the background radiation with the brightness temperature up to 8000 K is demonstrated.

  9. Properties of triplet-excited [N]cycloparaphenylenes (N = 8-12): excitation energies lower than those of linear oligomers and polymers.

    PubMed

    Fujitsuka, Mamoru; Lu, Chao; Iwamoto, Takahiro; Kayahara, Eiichi; Yamago, Shigeru; Majima, Tetsuro

    2014-06-26

    Cycloparaphenylenes (CPPs), a class of hoop-shaped conjugated macrocycles, have attracted the attention of researchers in various fields because of their interesting properties. Although their properties in the singlet-excited state have been reported, there is no systematic information on the triplet-excited state. In the present study, the properties of triplet-excited [n]CPP (n = 8-12, where n denotes the number of phenyl rings) were comprehensively investigated. The phosphorescence peak shifted to the shorter-wavelength side with increasing ring size of the CPPs, indicating smaller triplet energy for smaller CPPs. It was found that the triplet energy of a smaller CPP is even smaller than those of poly(p-phenylene)s, indicating that small hoop-shaped conjugated macrocycles are effective in realizing low-band gap materials. By applying laser flash photolysis, the Tn-T1 absorption spectra of CPPs were obtained, from which the size-dependence of energy levels of higher triplet states were also determined. Generation of singlet oxygen by the energy transfer from a triplet-excited CPP was confirmed. The generation yield became smaller with increasing size of the CPP in accordance with the triplet yield. From these observations, the size-dependence of the deactivation pathways is explained. PMID:24914824

  10. An 8.12 μW wavelet denoising chip for PPG detection and portable heart rate monitoring in 0.18 μm CMOS

    NASA Astrophysics Data System (ADS)

    Xiang, Li; Xu, Zhang; Peng, Li; Xiaohui, Hu; Hongda, Chen

    2016-05-01

    A low power wavelet denoising chip for photoplethysmography (PPG) detection and portable heart rate monitoring is presented. To eliminate noise and improve detection accuracy, Harr wavelet (HWT) is chosen as the processing tool. An optimized finite impulse response structure is proposed to lower the computational complexity of proposed algorithm, which is benefit for reducing the power consumption of proposed chip. The modulus maxima pair location module is design to accurately locate the PPG peaks. A clock control unit is designed to further reduce the power consumption of the proposed chip. Fabricated with the 0.18 μm N-well CMOS 1P6M technology, the power consumption of proposed chip is only 8.12 μW in 1 V voltage supply. Validated with PPG signals in multiparameter intelligent monitoring in intensive care databases and signals acquired by the wrist photoelectric volume detection front end, the proposed chip can accurately detect PPG signals. The average sensitivity and positive prediction are 99.91% and 100%, respectively.

  11. Theoretical investigations of a high density cage compound 10-(1-nitro-1, 2, 3, 4-tetraazol-5-yl)) methyl-2, 4, 6, 8, 12-hexanitrohexaazaisowurtzitane.

    PubMed

    Zhang, Jian-ying; Du, Hong-chen; Wang, Fang; Gong, Xue-dong; Huang, Yin-sheng

    2012-01-01

    A new polynitro cage compound with the framework of HNIW and a tetrazole unit, i.e., 10-(1-nitro-1, 2, 3, 4-tetraazol-5-yl)) methyl-2, 4, 6, 8, 12-hexanitrohexaazaisowurtzitane (NTz-HNIW) has been proposed and studied by density functional theory (DFT) and molecular mechanics methods. Properties such as IR spectrum, heat of formation, thermodynamic properties, and crystal structure were predicted. The compound belongs to the Pbca space group, with the lattice parameters a = 15.07 Å, b = 12.56 Å, c = 18.34 Å, Z = 8, and ρ = 1.990 g·cm(-3). The stability of the compound was evaluated by the bond dissociation energies and results showed that the first step of pyrolysis is the rupture of the N-NO(2) bond in the side chain. The detonation properties were estimated by the Kamlet-Jacobs equations based on the calculated crystal density and heat of formation, and the results were 9.240 km·s(-1) for detonation velocity and 40.136 GPa for detonation pressure. The designed compound has high thermal stability and good detonation properties and is probably a promising high energy density compound (HEDC).

  12. Assessment of selenium and mercury in biological samples of normal and night blindness children of age groups (3-7) and (8-12) years.

    PubMed

    Afridi, Hassan Imran; Kazi, Tasneem Gul; Talpur, Farah Naz; Kazi, Atif; Arain, Sadaf Sadia; Arain, Salma Aslam; Brahman, Kapil Dev; Panhwar, Abdul Haleem; Khan, Naeemullah; Arain, Mariam Shazadi; Ali, Jamshed

    2015-03-01

    The causes of night blindness in children are multifactorial and particular consideration has been given to childhood nutritional deficiency, which is the most common problem found in underdeveloped countries. Such deficiency can result in physiological and pathological processes that in turn influence biological sample composition. This study was designed to compare the levels of selenium (Se) and mercury (Hg) in scalp hair, blood, and urine of night blindness children age ranged (3-7) and (8-12) years of both genders, comparing them to sex- and age-matched controls. A microwave-assisted wet acid digestion procedure was developed as a sample pretreatment for the determination of Se and Hg in biological samples of night blindness children. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, blood, and urine. The Se and Hg in biological samples were measured by electrothermal atomic absorption spectrometry and cold vapor atomic absorption spectrometry, prior to microwave acid digestion, respectively. The concentration of Se was decreased in scalp hair and blood samples of male and female night blindness children while Hg was higher in all biological samples as compared to referent subjects. The Se concentration was inversely associated with the risk of night blindness in both genders. These results add to an increasing body of evidence that Se is a protecting element for night blindness. These data present guidance to clinicians and other professional investigating deficiency of essential micronutrients in biological samples (scalp hair and blood) of night blindness children. PMID:25655123

  13. Investigation of geomagnetic disturbances (F=1-5 Hz) before strong EQs in Kamchatka region

    NASA Astrophysics Data System (ADS)

    Kopytenko, Y.; Ismaguilov, V.; Schekotov, A.; Molchanov, O.; Hayakawa, M.

    2007-05-01

    Regular observations of ULF electromagnetic disturbances at st. Karymshino in seismic active zone of Kamchatka peninsula were carried out by induction three-component high-sensitive magnetometer during 2001- 2003 years. Five seismic active periods with strong earthquakes (M>5) were displayed during this period. These EQs occurred at the Pacific at 20-60 km depth at 100-140 km distances to the East from the st. Karymshino. Analysis of normalized dynamic power spectra of data of high-sensitive (0.2 pT/sqrt(Hz)) three- component induction magnetometer achieved a significant disorder of daily variation and increasing of the magnetic disturbance intensities (from 0.2 to ~ 1 pT) in the whole investigated frequency range (1 - 5 Hz). The anomaly intensity increasing was observed during the 12-18 hours before main seismic shocks. Maximum of the increasing occurred during 4-6 hours before the EQs. A sharp decreasing of the magnetic disturbance intensities was observed 2-4 hours before the EQs. We suppose that physical processes in a hearth of forthcoming EQ lead to an irreversible avalanche-like formation of cracks and stimulation of the ULF electromagnetic disturbances.

  14. 47 CFR 15.219 - Operation in the band 510-1705 kHz.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Operation in the band 510-1705 kHz. 15.219... kHz. (a) The total input power to the final radio frequency stage (exclusive of filament or heater... ground lead (if used) shall not exceed 3 meters. (c) All emissions below 510 kHz or above 1705 kHz...

  15. 47 CFR 15.219 - Operation in the band 510-1705 kHz.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Operation in the band 510-1705 kHz. 15.219... kHz. (a) The total input power to the final radio frequency stage (exclusive of filament or heater... ground lead (if used) shall not exceed 3 meters. (c) All emissions below 510 kHz or above 1705 kHz...

  16. 47 CFR 15.219 - Operation in the band 510-1705 kHz.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation in the band 510-1705 kHz. 15.219... kHz. (a) The total input power to the final radio frequency stage (exclusive of filament or heater... ground lead (if used) shall not exceed 3 meters. (c) All emissions below 510 kHz or above 1705 kHz...

  17. 47 CFR 15.219 - Operation in the band 510-1705 kHz.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Operation in the band 510-1705 kHz. 15.219... kHz. (a) The total input power to the final radio frequency stage (exclusive of filament or heater... ground lead (if used) shall not exceed 3 meters. (c) All emissions below 510 kHz or above 1705 kHz...

  18. 47 CFR 15.219 - Operation in the band 510-1705 kHz.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Operation in the band 510-1705 kHz. 15.219... kHz. (a) The total input power to the final radio frequency stage (exclusive of filament or heater... ground lead (if used) shall not exceed 3 meters. (c) All emissions below 510 kHz or above 1705 kHz...

  19. The Effect of the 226-Hz Probe Level on Contralateral Acoustic Stapedius Reflex Thresholds

    ERIC Educational Resources Information Center

    Day, Jessica E.; Feeney, M. Patrick

    2008-01-01

    Purpose: The purpose of this study was to examine the effect of the 226-Hz probe level on the acoustic stapedius reflex threshold. Method: Contralateral reflex thresholds for a 1000-Hz pure-tone stimulus were obtained from 40 young adults with normal hearing using an experimental system at four 226-Hz probe levels (70, 75, 80, and 85 dB SPL) with…

  20. 47 CFR 15.221 - Operation in the band 525-1705 kHz.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Operation in the band 525-1705 kHz. 15.221... kHz. (a) Carrier current systems and transmitters employing a leaky coaxial cable as the radiating antenna may operate in the band 525-1705 kHz provided the field strength levels of the radiated...

  1. 47 CFR 80.147 - Watch on 2182 kHz.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Watch on 2182 kHz. 80.147 Section 80.147 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE... 2182 kHz. Ship stations must maintain a watch on 2182 kHz as prescribed by § 80.304....

  2. 47 CFR 15.221 - Operation in the band 525-1705 kHz.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Operation in the band 525-1705 kHz. 15.221... kHz. (a) Carrier current systems and transmitters employing a leaky coaxial cable as the radiating antenna may operate in the band 525-1705 kHz provided the field strength levels of the radiated...

  3. 47 CFR 90.253 - Use of frequency 5167.5 kHz.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Use of frequency 5167.5 kHz. 90.253 Section 90.253 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES... frequency 5167.5 kHz. The frequency 5167.5 kHz may be used by any station authorized under this part...

  4. 47 CFR 80.147 - Watch on 2182 kHz.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Watch on 2182 kHz. 80.147 Section 80.147 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE... 2182 kHz. Ship stations must maintain a watch on 2182 kHz as prescribed by § 80.304....

  5. 47 CFR 90.253 - Use of frequency 5167.5 kHz.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Use of frequency 5167.5 kHz. 90.253 Section 90.253 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES... frequency 5167.5 kHz. The frequency 5167.5 kHz may be used by any station authorized under this part...

  6. 47 CFR 90.253 - Use of frequency 5167.5 kHz.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Use of frequency 5167.5 kHz. 90.253 Section 90.253 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES... frequency 5167.5 kHz. The frequency 5167.5 kHz may be used by any station authorized under this part...

  7. 47 CFR 90.253 - Use of frequency 5167.5 kHz.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Use of frequency 5167.5 kHz. 90.253 Section 90.253 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES... frequency 5167.5 kHz. The frequency 5167.5 kHz may be used by any station authorized under this part...

  8. 47 CFR 90.253 - Use of frequency 5167.5 kHz.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Use of frequency 5167.5 kHz. 90.253 Section 90.253 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES... frequency 5167.5 kHz. The frequency 5167.5 kHz may be used by any station authorized under this part...

  9. 47 CFR 80.147 - Watch on 2182 kHz.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Watch on 2182 kHz. 80.147 Section 80.147 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE... 2182 kHz. Ship stations must maintain a watch on 2182 kHz as prescribed by § 80.304....

  10. 47 CFR 80.147 - Watch on 2182 kHz.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Watch on 2182 kHz. 80.147 Section 80.147 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE... 2182 kHz. Ship stations must maintain a watch on 2182 kHz as prescribed by § 80.304....

  11. 47 CFR 15.221 - Operation in the band 525-1705 kHz.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Operation in the band 525-1705 kHz. 15.221... kHz. (a) Carrier current systems and transmitters employing a leaky coaxial cable as the radiating antenna may operate in the band 525-1705 kHz provided the field strength levels of the radiated...

  12. 47 CFR 15.221 - Operation in the band 525-1705 kHz.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Operation in the band 525-1705 kHz. 15.221... kHz. (a) Carrier current systems and transmitters employing a leaky coaxial cable as the radiating antenna may operate in the band 525-1705 kHz provided the field strength levels of the radiated...

  13. 47 CFR 15.221 - Operation in the band 525-1705 kHz.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation in the band 525-1705 kHz. 15.221... kHz. (a) Carrier current systems and transmitters employing a leaky coaxial cable as the radiating antenna may operate in the band 525-1705 kHz provided the field strength levels of the radiated...

  14. 47 CFR 80.147 - Watch on 2182 kHz.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Watch on 2182 kHz. 80.147 Section 80.147 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE... 2182 kHz. Ship stations must maintain a watch on 2182 kHz as prescribed by § 80.304....

  15. 20 kHz Space Station power system

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.; Wolff, Fredrick J.

    1986-01-01

    The Space Station represents the next major U.S. commitment in space. The efficient delivery of power to multiple user loads is key to that success. In 1969, NASA Lewis Research Center began a series of studies with component and circuit developments that led to the high frequency bi-directional, four quadrant resonant driven converter. Additional studies and subsequent developments into the early 1980's have shown how the high frequency ac power system could provide overall advantages to many aerospace power systems. Because of its wide versatility, it also has outstanding advantages for the Space Station Program and its wide range of users. High frequency ac power provides higher efficiency, lower cost, and improved safety. The 20 kHz power system has exceptional flexibility, is inherently user friendly, and is compatible with all types of energy sources - photovoltaic, solar dynamic, rotating machines or nuclear Lewis distribution system testbed. The testbed demonstrates flexibility, versatility, and transparency to user technology as well as high efficiency, low mass, and reduced volume.

  16. Cardiovascular response of rats exposed to 60-Hz electric fields

    SciTech Connect

    Hilton, D.I.; Phillips, R.D.

    1980-01-01

    Recently, it has been reported that exposure to high-strength electric fields can influence electrocardiogram (ECG) patterns, heart rates, and blood pressures in various species of animals. Our studies were designed to evaluate these reported effects and to help clarify some of the disagreement present in the literature. Various cardiovascular variables were measured in Sprague-Dawley rats exposed or sham-exposed to 60-Hz electric fields at 80 to 100 kV/m for periods up to four months. No significant differences in heart rates, ECG patterns, blood pressures, or vascular reactivity were observed between exposed and sham-exposed rats after 8 hours, 40 hours, 1 month, or 4 months of exposure. Our studies cannot be directly compared to the work of other investigators because of differences in animal species and electric-field characteristics. However, our failure to detect any cardiovascular changes may have been the result of (1) eliminating secondary field effects such as shocks, audible noise, corona, and ozone; (2) minimizing steady-state microcurrents between the mouth of the animal and watering devices; and (3) minimizing electric-field-induced vibration of the electrodes and animal cages.

  17. Cryogenic engineering and superconductor technology; Proceedings of the 14th International Cryogenic Engineering Conference and International Cryogenic Materials Conference, Kiev, Ukraine, June 8-12, 1992

    NASA Astrophysics Data System (ADS)

    Komarek, P.; Rizzuto, C.

    Consideration is given to application concepts of small regenerative cryocoolers in superconducting magnet systems, thermoelectric materials for Peltier cryogenic coolers, closed-cycle liquid helium refrigerators, built-in cryogenic control fixtures with electric drive, large cryogenic helium systems for superconducting magnets, low temperature adsorptive hydrogen isotope separation, cryogenic thermometry for space testing systems, performance of parallel flow He-II heat exchangers, and transient heat transfer to liquid helium at a 100 Hz pulsed heat load. Also discussed are He II cooling of a large superconducting magnet system, a computer code for simulation of thermal processes during quench in superconducting magnet windings, quench energies of multistable composite superconductors, a superconducting hydrogen-cooled switch on Nb-Sn tape, a gravity radiometer with coupled superconducting suspensions, new design of RSFQ logic family, and high-temperature Josephson junctions and their applications.

  18. Repeated amphetamine administration and long-term effects on 50-kHz ultrasonic vocalizations: possible relevance to the motivational and dopamine-stimulating properties of the drug.

    PubMed

    Simola, Nicola; Morelli, Micaela

    2015-03-01

    Ultrasonic vocalizations (USVs) of 50kHz are thought to indicate positive affective states in rats, and are increasingly being used to investigate the motivational properties of drugs of abuse. However, previous studies have observed that only dopaminergic psychostimulants of abuse, but not other addictive drugs, stimulate 50-kHz USVs immediately after their administration. This would suggest that 50-kHz USVs induced by addictive dopaminergic psychostimulants might reflect rewarding dopaminergic effect, rather than motivational effect. To elucidate this issue, our study compared the effects of the psychostimulant of abuse amphetamine and the dopamine receptor agonist apomorphine on 50-kHz USVs. Rats that received five drug administrations on alternate days in a novel test-cage were first re-exposed to the test-cage 7 days after treatment discontinuation to assess drug-conditioning, and then received a drug challenge. USVs were recorded throughout the experiments together with locomotor activity. To further clarify how amphetamine and apomorphine influenced 50-kHz USVs, rats were subdivided into "low" and "high" vocalizers, and time-dependence of drug effects was assessed. Amphetamine and apomorphine stimulated both 50-kHz USVs and locomotor activity, though they elicited dissimilar changes in these behaviors, depending on drug dose, rats׳ individual predisposition to vocalize, and time. Moreover, only amphetamine-treated rats displayed both sensitized 50-kHz USVs emission and conditioned vocalizations on test-cage re-exposure. These results indicate that the effects of amphetamine on 50-kHz USVs are not mimicked by a dopaminergic agonist with a low abuse potential, and may further support the usefulness of 50-kHz USVs in the study of the motivational properties of psychoactive drugs.

  19. Repeated amphetamine administration and long-term effects on 50-kHz ultrasonic vocalizations: possible relevance to the motivational and dopamine-stimulating properties of the drug.

    PubMed

    Simola, Nicola; Morelli, Micaela

    2015-03-01

    Ultrasonic vocalizations (USVs) of 50kHz are thought to indicate positive affective states in rats, and are increasingly being used to investigate the motivational properties of drugs of abuse. However, previous studies have observed that only dopaminergic psychostimulants of abuse, but not other addictive drugs, stimulate 50-kHz USVs immediately after their administration. This would suggest that 50-kHz USVs induced by addictive dopaminergic psychostimulants might reflect rewarding dopaminergic effect, rather than motivational effect. To elucidate this issue, our study compared the effects of the psychostimulant of abuse amphetamine and the dopamine receptor agonist apomorphine on 50-kHz USVs. Rats that received five drug administrations on alternate days in a novel test-cage were first re-exposed to the test-cage 7 days after treatment discontinuation to assess drug-conditioning, and then received a drug challenge. USVs were recorded throughout the experiments together with locomotor activity. To further clarify how amphetamine and apomorphine influenced 50-kHz USVs, rats were subdivided into "low" and "high" vocalizers, and time-dependence of drug effects was assessed. Amphetamine and apomorphine stimulated both 50-kHz USVs and locomotor activity, though they elicited dissimilar changes in these behaviors, depending on drug dose, rats׳ individual predisposition to vocalize, and time. Moreover, only amphetamine-treated rats displayed both sensitized 50-kHz USVs emission and conditioned vocalizations on test-cage re-exposure. These results indicate that the effects of amphetamine on 50-kHz USVs are not mimicked by a dopaminergic agonist with a low abuse potential, and may further support the usefulness of 50-kHz USVs in the study of the motivational properties of psychoactive drugs. PMID:25638025

  20. Chronic exposure to 60-Hz electric fields: effects on pineal function in the rat

    SciTech Connect

    Wilson, B.W.; Anderson, L.E.; Hilton, D.I.; Philips, R.D.

    1980-01-01

    As a component of studies to search for effects of 60-Hz electric field exposure on mammalian endocrine function, concentrations of melatonin, 5-methoxytryptophol, and serotonin-N-acetyl transferase activity were measured in the pineal glands of rats exposed or sham-exposed at 65 kV/m for 30 days.In two replicate experiments there were statistically significant differences between exposed and control rats in that the normal nocturnal increase in pineal melatonin content was depressed in the exposed animals. Concentrations of 5-methoxytryptophol were increased in the pineal glands of the exposed groups when compared to sham-exposed controls. An alteration was also observed in serotonin-N-acetyl transferase activity, with lower levels measured in pineal glands from exposed animals.

  1. The inhibitory and combinative mechanism of HZ08 with P-glycoprotein expressed on the membrane of Caco-2 cell line

    SciTech Connect

    Zhang, Yanyan; Hu, Yahui; Feng, Yidong; Kodithuwakku, Nandani Darshika; Fang, Weirong; Li, Yunman; Huang, Wenlong

    2014-01-15

    Recently, the research and development of agents to reverse the phenomenon of multidrug resistance has been an attractive goal as well as a key approach to elevating the clinical survival of cancer patients. Although three generations of P-glycoprotein modulators have been identified, poor clearance and metabolism render these agents too toxic to be used in clinical application. HZ08, which has been under investigation for several years, shows a dramatic reversal effect with low cytotoxicity. For the first time, we aimed to describe the interaction between HZ08 and P-glycoprotein in Caco-2 cell line in which P-glycoprotein is overexpressed naturally. Cytotoxicity and multidrug resistance reversal assays, together with flow cytometry, fluorescence microscopy and siRNA interference as well as Caco-2 monolayer transport model were employed in this study to evaluate the interaction between HZ08 and P-glycoprotein. This study revealed that HZ08 was capable of reversing adriamycin resistance mediated by P-glycoprotein as a result of intracellular enhancement of adriamycin accumulation, which was found to be superior to verapamil. In addition, we confirmed that HZ08 suppressed the transport of Rhodamine123 in the Caco-2 monolayer model but had little effect on P-glycoprotein expression. The transport of HZ08 was diminished by P-glycoprotein inhibitors (verapamil and LY335979) and its accumulation was increased via siRNA targeting MDR1 in Caco-2 cells. Furthermore, considering the binding site of P-glycoprotein, verapamil performed as a competitive inhibitor with HZ08. In conclusion, as a P-glycoprotein substrate, HZ08 inhibited P-glycoprotein activity and may share the same binding site of verapamil to P-glycoprotein. - Highlights: • The cytotoxicity and reversing effect of HZ08 was measured in Caco-2 cell line. • HZ08 inhibited the transport of Rhodamine123 across Caco-2 cell monolayer. • The efflux ratio of HZ08 was dropped when combined with P

  2. Cochlear nonlinearity between 500 and 8000 Hz in listeners with moderate cochlear hearing loss

    NASA Astrophysics Data System (ADS)

    Lopez-Poveda, Enrique A.; Plack, Christopher J.; Meddis, Ray; Blanco, Jose L.

    2001-05-01

    For two listeners with flat hearing loss, temporal masking curves (TMCs) were measured for probe frequencies (Fp) of 0.5, 1.0, 2.0, 4.0, and 8.0 kHz and masker frequencies of 0.5, 0.6, 0.7, 0.9, 1.0, 1.05, 1.1, and 1.2 Fp. From these, basilar membrane (BM) input/output (IO) functions and psychophysical tuning curves (PTCs) were derived and compared with corresponding data for normal-hearing listeners. Linear IO functions were observed for one ear only and for probe frequencies of 4 kHz and above. This result is consistent with the consequences of severe outer hair cell (OHC) damage on the BM response. Elsewhere, however, IO functions showed residual compression, with slopes in the compression region close to normal. This suggests that either the impairment relates mostly to inner hair cell (IHC) dysfunction, or that OHC dysfunction reduces the gain of the BM at low levels while maintaining the degree of maximum compression. The data suggest that the active and the passive BM mechanisms have different relative positions (in frequency) in the apical and the basal regions of the cochlea. Across probe frequencies, the slopes of the TMCs for off-frequency maskers are shallower for the impaired ears. It is considered that this possibly reflects IHC-related compression.

  3. The effect of wind-generated bubbles on sea-surface backscattering at 940 Hz.

    PubMed

    van Vossen, Robbert; Ainslie, Michael A

    2011-11-01

    Reliable predictions of sea-surface backscattering strength are required for sonar performance modeling. These are, however, difficult to obtain as measurements of sea-surface backscattering are not available at small grazing angles relevant to low-frequency active sonar (1-3 kHz). Accurate theoretical predictions of scattering strength require a good understanding of physical mechanisms giving rise to the scattering and the relative importance of these. In this paper, scattering from individual resonant bubbles is introduced as a potential mechanism and a scattering model is derived that incorporates the contribution from these together with that of rough surface scattering. The model results are fitted to Critical Sea Test (CST) measurements at a frequency of 940 Hz, treating the number of large bubbles, parameterized through the spectral slope of the size spectrum for bubbles whose radii exceed 1 mm, as a free parameter. This procedure illustrates that the CST data can be explained by scattering from a small number of large resonant bubbles, indicating that these provide an alternative mechanism to that of scattering from bubble clouds.

  4. Behavioral studies with mice exposed to DC and 60-Hz magnetic fields

    SciTech Connect

    Davis, H.P.; Mizumori, S.J.Y.; Allen, H.; Rosenzweig, M.R.; Bennett, E.L.; Tenforde, T.S.

    1984-01-01

    Behavioral measures were evaluated in adult CD-1 and LAF-1 mice continuously exposed for 72 h to a 1.5-Tesla (1 T = 10/sup 4/ Gauss) homogeneous DC magnetic field, and in LAF-1 mice continuously exposed for 72 h to a sinusoidal 60-Hz, 1.65-mT (rms) homogeneous AC field. Three types of behavioral tests were employed: (1) memory of an electroshock-motivated passive avoidance task was assessed in animals that had been trained immediately prior to the field exposure. The strength of memory was varied either by altering the strength of the electric footshock during training, or by administering a cerebral protein synthesis inhibitor, anisomycin, at the time of training. (2) General locomotor activity was measured using a quadrant-crossing test immediately after termination of the magnetic field exposure. (3) Sensitivity of the experimental subjects to the seizure-inducing neuropharmacological agent, pentylenetetrazole, was assessed immediately after the field exposure on the basis of three criteria: (a) the percentage of subjects exhibiting a generalized seizure, (b) the mean time to seizure, and (c) the mean seizure level. The results of these studies revealed no behavior alterations in exposed mice relative to controls in any of the experimental tests with the 1.5-T DC field or the 60-Hz, 1.65-mT (rms) AC field. 57 references, 6 figures, 1 table.

  5. Are the kHz QPO Lags in Neutron Star 4U 1608–52 due to Reverberation?

    NASA Astrophysics Data System (ADS)

    Cackett, Edward M.

    2016-08-01

    X-ray reverberation lags have recently been discovered in both active galactic nuclei (AGNs) and black hole X-ray binaries. A recent study of the neutron star low-mass X-ray binary (LMXB) 4U 1608‑52 has also shown significant lags, whose properties hint at a reverberation origin. Here, we adapt general relativistic ray tracing impulse response functions used to model X-ray reverberation in AGNs for neutron star LMXBs. Assuming that relativistic reflection forms the broad iron line and associated reflection continuum, we use reflection fits to the energy spectrum along with the impulse response functions to calculate the expected lags as a function of energy over the range of observed kHz quasi-periodic oscillation (QPO) frequencies in 4U 1608‑52. We find that the lag energy spectrum is expected to increase with increasing energy above 8 keV, while the observed lags in 4U 1608‑52 show the opposite behavior. This demonstrates that the lags in the lower kHz QPO of 4U 1608‑52 are not solely due to reverberation. We do note, however, that the models appear to be more consistent with the much flatter lag energy spectrum observed in the upper kHz QPO of several neutron star LMXBs, suggesting that lower and upper kHz QPOs may have different origins.

  6. Cardiovascular rhythms in the 0.15-Hz band: common origin of identical phenomena in man and dog in the reticular formation of the brain stem?

    PubMed

    Perlitz, Volker; Lambertz, Manfred; Cotuk, Birol; Grebe, Reinhard; Vandenhouten, Ralf; Flatten, Guido; Petzold, Ernst Richard; Schmid-Schönbein, Holger; Langhorst, Peter

    2004-09-01

    Selected examples from experiments in humans and dogs with time series of reticular neurons, respiration, arterial blood pressure and cutaneous forehead blood content fluctuations were analysed using multiscaled time-frequency distribution, post-event-scan and pointwise transinformation. We found in both experiments a "0.15-Hz rhythm" exhibiting periods of spindle waves (increasing and decreasing amplitudes), phase synchronized with respiration at 1:2 and 1:1 integer number ratios. At times of wave-epochs and n:m phase synchronization, the 0.15-Hz rhythm appeared in heart rate and arterial blood pressure. As phase synchronization of the 0.15-Hz rhythm with respiration was established at a 1:1 integer number ratio, all cardiovascular-respiratory oscillations were synchronized at 0.15 Hz. Analysis of a canine experiment supplied evidence that the emergence of the 0.15-Hz rhythm and n:m phase synchronization appears to result from a decline in the level of the general activity of the organism associated with a decline in the level of activity of reticular neurons in the lower brainstem network. These findings corroborate the notion of the 0.15-Hz rhythm as a marker of the "trophotropic mode of operation" first introduced by W.R. Hess. PMID:15138824

  7. Cardiovascular rhythms in the 0.15-Hz band: common origin of identical phenomena in man and dog in the reticular formation of the brain stem?

    PubMed

    Perlitz, Volker; Lambertz, Manfred; Cotuk, Birol; Grebe, Reinhard; Vandenhouten, Ralf; Flatten, Guido; Petzold, Ernst Richard; Schmid-Schönbein, Holger; Langhorst, Peter

    2004-09-01

    Selected examples from experiments in humans and dogs with time series of reticular neurons, respiration, arterial blood pressure and cutaneous forehead blood content fluctuations were analysed using multiscaled time-frequency distribution, post-event-scan and pointwise transinformation. We found in both experiments a "0.15-Hz rhythm" exhibiting periods of spindle waves (increasing and decreasing amplitudes), phase synchronized with respiration at 1:2 and 1:1 integer number ratios. At times of wave-epochs and n:m phase synchronization, the 0.15-Hz rhythm appeared in heart rate and arterial blood pressure. As phase synchronization of the 0.15-Hz rhythm with respiration was established at a 1:1 integer number ratio, all cardiovascular-respiratory oscillations were synchronized at 0.15 Hz. Analysis of a canine experiment supplied evidence that the emergence of the 0.15-Hz rhythm and n:m phase synchronization appears to result from a decline in the level of the general activity of the organism associated with a decline in the level of activity of reticular neurons in the lower brainstem network. These findings corroborate the notion of the 0.15-Hz rhythm as a marker of the "trophotropic mode of operation" first introduced by W.R. Hess.

  8. Cortico-muscular coupling and motor performance are modulated by 20 Hz transcranial alternating current stimulation (tACS) in Parkinson’s disease

    PubMed Central

    Krause, Vanessa; Wach, Claudia; Südmeyer, Martin; Ferrea, Stefano; Schnitzler, Alfons; Pollok, Bettina

    2014-01-01

    Parkinson’s disease (PD) is associated with pathologically altered oscillatory activity. While synchronized oscillations between 13 and 30 Hz are increased within a cortico-subcortical network, cortico-muscular coupling (CMC) is decreased. The present study aims at investigating the effect of non-invasive transcranial alternating current stimulation (tACS) of the primary motor cortex (M1) on motor symptoms and motor-cortical oscillations in PD. In 10 PD patients and 10 healthy control subjects, static isometric contraction, dynamic fast finger tapping, and diadochokinesia of the more severely affected hand were investigated prior to and shortly after tACS of the contralateral M1 at 10 Hz vs. 20 Hz vs. sham. During isometric contraction, neuromagnetic activity was recorded using magnetoencephalography. 20 Hz tACS attenuated beta band CMC during isometric contraction and amplitude variability during finger tapping in PD patients but not in healthy control subjects. 10 Hz tACS yielded no significant after-effects. The present data suggest that PD is associated with pathophysiological alterations which abet a higher responsiveness toward frequency-specific tACS – possibly due to pathologically altered motor-cortical oscillatory synchronization at frequencies between 13 and 30 Hz. PMID:24474912

  9. Habitability of terrestrial-mass planets in the HZ of M Dwarfs - I. H/He-dominated atmospheres

    NASA Astrophysics Data System (ADS)

    Owen, James E.; Mohanty, Subhanjoy

    2016-07-01

    The ubiquity of M dwarfs, combined with the relative ease of detecting terrestrial-mass planets around them, has made them prime targets for finding and characterizing planets in the `habitable zone' (HZ). However, Kepler finds that terrestrial-mass exoplanets are often born with voluminous H/He envelopes, comprising mass-fractions (Menv/Mcore) ≳1 per cent. If these planets retain such envelopes over Gyr time-scales, they will not be `habitable' even within the HZ. Given the strong X-ray/UV fluxes of M dwarfs, we study whether sufficient envelope mass can be photoevaporated away for these planets to become habitable. We improve upon previous work by using hydrodynamic models that account for radiative cooling as well as the transition from hydrodynamic to ballistic escape. Adopting a template active M dwarf XUV spectrum, including stellar evolution, and considering both evaporation and thermal evolution, we show that: (1) the mass-loss is (considerably) lower than previous estimates that use an `energy-limited' formalism and ignore the transition to Jeans escape; (2) at the inner edge of the HZ, planets with core mass ≲ 0.9 M⊕ can lose enough H/He to become habitable if their initial envelope mass-fraction is ˜1 per cent; (3) at the outer edge of the HZ, evaporation cannot remove a ˜1 per cent H/He envelope even from cores down to 0.8 M⊕. Thus, if planets form with bulky H/He envelopes, only those with low-mass cores may eventually be habitable. Cores ≳1 M⊕, with ≳1 per cent natal H/He envelopes, will not be habitable in the HZ of M dwarfs.

  10. Instrumental Conditioning of Human Sensorimotor Rhythm (12–15 Hz) and Its Impact on Sleep as Well as Declarative Learning

    PubMed Central

    Hoedlmoser, Kerstin; Pecherstorfer, Thomas; Gruber, Georg; Anderer, Peter; Doppelmayr, Michael; Klimesch, Wolfgang; Schabus, Manuel

    2008-01-01

    Study Objectives: To test whether instrumental conditioning of sensorimotor rhythm (SMR; 12–15 Hz) has an impact on sleep parameters as well as declarative memory performance in humans. Design: Randomized, parallel group design Setting: 10 instrumental conditioning sessions, pre- and posttreatment investigation including sleep evaluations Participants: 27 healthy subjects (13 male) Interventions: SMR-conditioning (experimental group) or randomized-frequency conditioning (control group); declarative memory task before and after a 90-min nap Measurement and Results: The experimental group was trained to enhance the amplitude of their SMR-frequency range, whereas the control group participated in a randomized-frequency conditioning program (i.e., every session a different 3-Hz frequency bin between 7 and 20 Hz). During pre- and posttreatment the subjects had to attend the sleep laboratory to take a 90-min nap (2:00–3:30 pm) and to perform a declarative memory task before and after sleep. The experimental design was successful in conditioning an increase in relative 12–15 Hz amplitude within 10 sessions (d = 0.7). Increased SMR activity was also expressed during subsequent sleep by eliciting positive changes in different sleep parameters (sleep spindle number [d = 0.6], sleep onset latency [d = 0.7]); additionally, this increased 12–15 Hz amplitude was associated with enhancement in retrieval score computed at immediate cued recall (d = 0.9). Conclusion: Relative SMR amplitude increased over 10 instrumental conditioning sessions (in the experimental group only) and this “shaping of one's own brain activity” improved subsequent declarative learning and facilitated the expression of 12–15 Hz spindle oscillations during sleep. Most interestingly, these electrophysiological changes were accompanied by a shortened sleep onset latency. Citation: Hoedlmoser K; Pecherstorfer T; Gruber G; Anderer P; Doppelmayr M; Klimesch W; Schabus M. Instrumental conditioning of

  11. Final Report. Supplementary comparison of 50/60 Hz energy SIM.EM-S7

    NASA Astrophysics Data System (ADS)

    Carranza, R.; Campos, S.; Castruita, A.; Nelson, T.; Ribeiro, A. M.; So, E.; Spaggiari, A.; Slomovitz, D.; Izquierdo, D.; Postigo, H.; Díaz, H.; Sanchez, H.; Gonzalez, J.; Ramos, R.; Zipaquira, A.

    2016-01-01

    From 2010 to 2012, a key comparison of energy standards at 50/60 Hz was conducted in the SIM region. The comparison included measurements of active and reactive energy at three frequencies, aiming at providing support to high accuracy measurement needs of reactive energy. This work presents the results of the SIM.EM-S7 supplementary comparison. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  12. Transmission loss measurements and geoacoustic sensitivity modeling at 1.2 kHz.

    PubMed

    Pecknold, Sean P; Masui, Kiyoshi W; Hines, Paul C

    2008-09-01

    The Shallow Water Experiment 2006 was conducted off the coast of New Jersey in the summer of 2006. Defence Research and Development Canada-Atlantic performed a series of experiments designed to validate the use of rapid environmental assessment tools and methods to improve active sonar performance predictions. The sensitivity of acoustic propagation to a varying or uncertain environment is determined by examining the relative change of acoustic pressure caused by environmental variability, using the method described recently [Dosso et al., J. Acoust. Soc. Am. 121, 42 (2007)]. The variability of the modeled environmental parameters is based on measured and estimated oceanographic and geoacoustic properties. The resulting sensitivity is compared to measured transmission loss data at 1.2 kHz.

  13. Energy metabolism in human calf muscle performing isometric plantar flexion superimposed by 20-Hz vibration.

    PubMed

    Zange, Jochen; Haller, Timo; Müller, Klaus; Liphardt, Anna-Maria; Mester, Joachim

    2009-01-01

    Vibration training is commonly expected to induce an active muscle contraction via a complex reflex mechanism. In calf muscles of 20 untrained subjects, the additional energy consumption in response to vibration superimposed on an isometric contraction was examined by (31)P magnetic resonance spectroscopy and by near infrared spectroscopy. Subjects performed 3 min of isometric plantar flexion exercise at 40% MVC under four conditions: with (VIB) and without (CON) superimposed 20 Hz vibration at +/-2 mm amplitude, both combined with or without arterial occlusion (AO). After contraction under all conditions, the decreases in oxygenated haemoglobin were not significantly different. After VIB + AO consumption of ATP was increased by 60% over CON + AO, visible by significant decreases in [PCr] and intracellular pH (P < 0.05). The additional energy consumption by vibration was not detectable under natural perfusion. Probably without AO the additional energy consumption by vibration was compensated by oxidative phosphorylation enabled by additional perfusion.

  14. Evaluating parallel architectures for two real-time applications with 100 kHz repetition rate

    SciTech Connect

    Baldier, J.; Busson, Ph.; Charlot, C. ); Centro, S.; Pascoli, D ); Davis, E.E.; Ni, P. ); Denes, E.; Odor, G.; Vesztergombi ); Gheorghe, A.; Legrand, I. ); Klefenz, F.; Maenner, R.; Noffz, K.H.; Zoz, R. ); Lourens, W.; Taal, A. ); Malecki, P.; Sobala, A. ); Thielmann, A. ); Vermeulen, J. )

    1993-02-01

    In the context of Research and Development (R and D) activities for future hadron colliders, competitive implementations of real-time algorithms for feature extraction have been made on various forms of commercial pipelined and parallel architectures. The algorithms used for benchmarking serve for decision making and are of relative complexity; they are required to run with a repetition rate of 1,000 kHz in data sets of kilobyte size. Results are reported and discussed in detail. Among the commercially available architectures, pipelined image processing systems can compete with custom-designed architectures. General-purpose processors with systolic mesh connectivity can also be used. Massively parallel systems of the SIMD type (many processors executing the same program on different data) are less suitable in the presently marketed form.

  15. Effects of a 50 Hz magnetic field on Dictyostelium discoideum (Protista).

    PubMed

    Amaroli, Andrea; Trielli, Francesca; Bianco, Bruno; Giordano, Stefano; Moggia, Elsa; Corrado, Maria Umberta Delmonte

    2006-10-01

    Some studies have demonstrated that a few biological systems are affected by weak, extremely low frequency (ELF) electromagnetic fields (EMFs), lower than 10 mT. However, to date there is scanty evidence of this effect on Protists in the literature. Due to their peculiarity as single-cell eukaryotic organisms, Protists respond directly to environmental stimuli, thus appearing as very suitable experimental systems. Recently, we showed the presence of propionylcholinesterase (PrChE) activity in single-cell amoebae of Dictyostelium discoideum. This enzyme activity was assumed to be involved in cell-cell and cell-environment interactions, as its inhibition affects cell aggregation and differentiation. In this work, we have exposed single-cell amoebae of D. discoideum to an ELF-EMF of about 200 microT, 50 Hz, for 3 h or 24 h at 21 degrees C. A delay in the early phase of the differentiation was observed in 3 h exposed cells, and a significant decrease in the fission rate appeared in 24 h exposed cells. The PrChE activity was significantly lower in 3 h exposed cells than in the controls, whereas 24 h exposed cells exhibited an increase in this enzyme activity. However, such effects appeared to be transient, as the fission rate and PrChE activity values returned to the respective control values after a 24 h stay under standard conditions.

  16. A TEST OF COSMOLOGICAL MODELS USING HIGH-z MEASUREMENTS OF H(z)

    SciTech Connect

    Melia, Fulvio; McClintock, Thomas M. E-mail: tmcclintock89@gmail.com

    2015-10-15

    The recently constructed Hubble diagram using a combined sample of SNLS and SDSS-II SNe Ia, and an application of the Alcock–Paczyński (AP) test using model-independent Baryon Acoustic Oscillation (BAO) data, have suggested that the principal constraint underlying the cosmic expansion is the total equation-of-state of the cosmic fluid, rather than that of its dark energy. These studies have focused on the critical redshift range (0 ≲ z ≲ 2) within which the transition from decelerated to accelerated expansion is thought to have occurred, and they suggest that the cosmic fluid has zero active mass, consistent with a constant expansion rate. The evident impact of this conclusion on cosmological theory calls for an independent confirmation. In this paper, we carry out this crucial one-on-one comparison between the R{sub h} = ct universe (a Friedmann–Robertson–Walker cosmology with zero active mass) and wCDM/ΛCDM, using the latest high-z measurements of H(z). Whereas the SNe Ia yield the integrated luminosity distance, while the AP diagnostic tests the geometry of the universe, the Hubble parameter directly samples the expansion rate itself. We find that the model-independent cosmic chronometer data prefer R{sub h} = ct over wCDM/ΛCDM with a Bayes Information Criterion likelihood of ∼95% versus only ∼5%, in strong support of the earlier SNe Ia and AP results. This contrasts with a recent analysis of H(z) data based solely on BAO measurements which, however, strongly depend on the assumed cosmology. We discuss why the latter approach is inappropriate for model comparisons, and emphasize again the need for truly model-independent observations to be used in cosmological tests.

  17. Studies of selective attention in dogs using the energy characteristics of neocortical potentials in the frequency range 1-220 Hz.

    PubMed

    Dumenko, V N; Kozlov, M L; Kulikov, M A

    2002-01-01

    Experiments were performed in dogs to study the state of selective attention formed during operant food-related training and apparent during interstimulus intervals as a state of tense expectation of the conditioned signal. Electrical activity in various parts of the neocortex, in both hemispheres, was analyzed in the frequency range 1-220 Hz (epidural electrodes) using Fourier transforms. The electrical activity of the motor area of the right hemisphere showed a predominance of high-frequency (40-200 Hz) components, as did the visual and parietal areas of the left hemisphere. The state of selective attention was associated with a different functional mosaic in the organization of neocortical electrical activity.

  18. Effects on atmospherics at 6 kHz and 9 kHz recorded at Tripura during the India-Pakistan Border earthquake

    NASA Astrophysics Data System (ADS)

    de, S. S.; de, B. K.; Bandyopadhyay, B.; Paul, S.; Haldar, D. K.; Bhowmick, A.; Barui, S.; Ali, R.

    2010-04-01

    The outcome of the results of some analyses of electromagnetic emissions recorded by VLF receivers at 6 kHz and 9 kHz over Agartala, Tripura, the North-Eastern state of India (Lat. 23° N, Long. 91.4° E) during the large earthquake at Muzaffarabad (Lat. 34.53° N, Long. 73.58° E) at Kashmir under Pakistan have been presented here. Spiky variations in integrated field intensity of atmospherics (IFIA) at 6 and 9 kHz have been observed 10 days prior (from midnight of 28 September 2005) to the day of occurrence of the earthquake on 8 October 2005 and the effect continued, decayed gradually and eventually ceased on 16 October 2005. The spikes distinctly superimposed on the ambient level with mutual separation of 2-5 min. Occurrence number of spikes per hour and total duration of their occurrence have been found remarkably high on the day of occurrence of the earthquake. The spike heights are higher at 6 kHz than at 9 kHz. The results have been explained on the basis of generation of electromagnetic radiation associated with fracture of rocks, their subsequent penetration into the Earth's atmosphere and finally their propagation between Earth-ionosphere waveguide. The present observation shows that VLF anomaly is well-confined between 6 and 9 kHz.

  19. Analgesic effects of transcutaneous electrical nerve stimulation and interferential current on experimental ischemic pain models: frequencies of 50 hz and 100 hz.

    PubMed

    Bae, Young-Hyeon; Lee, Suk Min

    2014-12-01

    [Purpose] This study compared the analgesic effects of transcutaneous electrical nerve stimulation (TENS) and interferential currents (IFC) on induced ischemic pain in healthy volunteers. [Subjects] The subjects were 36 volunteers (18 male, 18 female) without known pathology that could cause pain. Their mean age was 24.5±2.2 years. [Methods] A single-blind and parallel-group method was used. Subjects were randomly allocated to receive each 50 Hz TENS, 50 Hz IFC, 100 Hz TENS, and 100 Hz IFC. This study experimentally induced ischemic pain in otherwise pain-free subjects using a modified version of the submaximal effort tourniquet technique. Subjects completed twelve cycles of the ischemic-induced pain test. The primary outcome measure was the change in self-reported of pain intensity during one of four possible treatments. [Results] There were significant effects for Time, which were attributed to a significant reduction in pain intensity for all groups. There were no significant effects for groups or group-time interaction. The 50 Hz IFC treatment was more comfortable than the other treatments in the present study, and it is likely to be better accepted and tolerated by patients. [Conclusion] We conclude that there were no differences in the analgesic effects of the four treatments under the present experimental conditions. The 50 Hz IFC treatment is more comfortable than the other treatments.

  20. 47 CFR 15.217 - Operation in the band 160-190 kHz.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Operation in the band 160-190 kHz. 15.217... Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.217 Operation in the band 160-190 k... lead (if used) shall not exceed 15 meters. (c) All emissions below 160 kHz or above 190 kHz shall...

  1. 47 CFR 15.217 - Operation in the band 160-190 kHz.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Operation in the band 160-190 kHz. 15.217... Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.217 Operation in the band 160-190 k... lead (if used) shall not exceed 15 meters. (c) All emissions below 160 kHz or above 190 kHz shall...

  2. 47 CFR 15.217 - Operation in the band 160-190 kHz.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Operation in the band 160-190 kHz. 15.217... Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.217 Operation in the band 160-190 k... lead (if used) shall not exceed 15 meters. (c) All emissions below 160 kHz or above 190 kHz shall...

  3. 47 CFR 15.217 - Operation in the band 160-190 kHz.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Operation in the band 160-190 kHz. 15.217... Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.217 Operation in the band 160-190 k... lead (if used) shall not exceed 15 meters. (c) All emissions below 160 kHz or above 190 kHz shall...

  4. 47 CFR 15.217 - Operation in the band 160-190 kHz.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation in the band 160-190 kHz. 15.217... Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.217 Operation in the band 160-190 k... lead (if used) shall not exceed 15 meters. (c) All emissions below 160 kHz or above 190 kHz shall...

  5. Identification of resting and active state EEG features of Alzheimer's disease using discrete wavelet transform.

    PubMed

    Ghorbanian, Parham; Devilbiss, David M; Verma, Ajay; Bernstein, Allan; Hess, Terry; Simon, Adam J; Ashrafiuon, Hashem

    2013-06-01

    Alzheimer's disease (AD) is associated with deficits in a number of cognitive processes and executive functions. Moreover, abnormalities in the electroencephalogram (EEG) power spectrum develop with the progression of AD. These features have been traditionally characterized with montage recordings and conventional spectral analysis during resting eyes-closed and resting eyes-open (EO) conditions. In this study, we introduce a single lead dry electrode EEG device which was employed on AD and control subjects during resting and activated battery of cognitive and sensory tasks such as Paced Auditory Serial Addition Test (PASAT) and auditory stimulations. EEG signals were recorded over the left prefrontal cortex (Fp1) from each subject. EEG signals were decomposed into sub-bands approximately corresponding to the major brain frequency bands using several different discrete wavelet transforms and developed statistical features for each band. Decision tree algorithms along with univariate and multivariate statistical analysis were used to identify the most predictive features across resting and active states, separately and collectively. During resting state recordings, we found that the AD patients exhibited elevated D4 (~4-8 Hz) mean power in EO state as their most distinctive feature. During the active states, however, the majority of AD patients exhibited larger minimum D3 (~8-12 Hz) values during auditory stimulation (18 Hz) combined with increased kurtosis of D5 (~2-4 Hz) during PASAT with 2 s interval. When analyzed using EEG recording data across all tasks, the most predictive AD patient features were a combination of the first two feature sets. However, the dominant discriminating feature for the majority of AD patients were still the same features as the active state analysis. The results from this small sample size pilot study indicate that although EEG recordings during resting conditions are able to differentiate AD from control subjects, EEG activity

  6. Electrophysiological signatures of intentional social coordination in the 10-12 Hz range.

    PubMed

    Naeem, Muhammad; Prasad, Girijesh; Watson, David R; Kelso, J A Scott

    2012-01-16

    This study sought to investigate the effects of manipulating social coordination on brain synchronization/de-synchronization in the mu band. Mu activation is associated with understanding and coordinating motor acts and may play a key role in mediating social interaction. Members of a dyad were required to interact with one another in a rhythmic finger movement coordination task under various instructions: intrinsic where each member of the dyad was instructed to maintain their own and ignore their partner's movement; in-phase where they were asked to synchronize with their partner's movement; and anti-phase where they were instructed to syncopate with their partner's movement. EEG and movement data were recorded simultaneously from both subjects during all three tasks and a control condition. Log power ratios of EEG activity in the active conditions versus control were used to assess the effect of task context on synchronization/de-synchronization in the mu spectral domain. Results showed clear and systematic modulation of mu band activity in the 10-12 Hz range as a function of coordination context. In the left hemisphere general levels of alpha-mu suppression increased progressively as one moved from intrinsic through in-phase to anti-phase contexts but with no specific central-parietal focus. In contrast the right hemisphere displayed context-specific changes in the central-parietal region. The intrinsic condition showed a right synchronization which disappeared with the in-phase context even as de-synchronization remained greater in the left hemisphere. Anti-phase was associated with larger mu suppression in the right in comparison with left at central-parietal region. Such asymmetrical changes were highly correlated with changing behavioral dynamics. These specific patterns of activation and deactivation of mu activity suggest that localized neural circuitry in right central-parietal regions mediates how individuals interpret the movements of others in the

  7. The rat suprachiasmatic nucleus: the master clock ticks at 30 Hz

    PubMed Central

    Tsuji, Takahiro; Tsuji, Chiharu; Ludwig, Mike

    2016-01-01

    Key points Light‐responsive neurones in the rat suprachiasmatic nucleus discharge with a harmonic distribution of interspike intervals, whereas unresponsive neurones seldom do.This harmonic patterning has a fundamental frequency of close to 30 Hz, and is the same in light‐on cells as in light‐off cells, and is unaffected by exposure to light.Light‐on cells are more active than light‐off cells in both subjective day and subjective night, and both light‐on cells and light‐off cells respond more strongly to changes in light intensity during the subjective night than during the subjective day.Paired recordings indicate that the discharge of adjacent light‐responsive cells is very tightly synchronized.The gap junction inhibitor carbenoxolone increases the spontaneous activity of suprachiasmatic nucleus neurones but does not block the harmonic discharge patterning. Abstract The suprachiasmatic nucleus (SCN) of the hypothalamus has an essential role in orchestrating circadian rhythms of behaviour and physiology. In the present study, we recorded from single SCN neurons in urethane‐anaesthetized rats, categorized them by the statistical features of their electrical activity and by their responses to light, and examined how activity in the light phase differs from activity in the dark phase. We classified cells as light‐on cells or light‐off cells according to how their firing rate changed in acute response to light, or as non‐responsive cells. In both sets of light‐responsive neurons, responses to light were stronger at subjective night than in subjective day. Neuronal firing patterns were analysed by constructing hazard functions from interspike interval data. For most light‐responsive cells, the hazard functions showed a multimodal distribution, with a harmonic sequence of modes, indicating that spike activity was driven by an oscillatory input with a fundamental frequency of close to 30 Hz; this harmonic pattern was rarely seen in non

  8. Frequency specific interactions of MEG resting state activity within and across brain networks as revealed by the multivariate interaction measure.

    PubMed

    Marzetti, L; Della Penna, S; Snyder, A Z; Pizzella, V; Nolte, G; de Pasquale, F; Romani, G L; Corbetta, M

    2013-10-01

    Resting state networks (RSNs) are sets of brain regions exhibiting temporally coherent activity fluctuations in the absence of imposed task structure. RSNs have been extensively studied with fMRI in the infra-slow frequency range (nominally <10(-1)Hz). The topography of fMRI RSNs reflects stationary temporal correlation over minutes. However, neuronal communication occurs on a much faster time scale, at frequencies nominally in the range of 10(0)-10(2)Hz. We examined phase-shifted interactions in the delta (2-3.5 Hz), theta (4-7 Hz), alpha (8-12 Hz) and beta (13-30 Hz) frequency bands of resting-state source space MEG signals. These analyses were conducted between nodes of the dorsal attention network (DAN), one of the most robust RSNs, and between the DAN and other networks. Phase shifted interactions were mapped by the multivariate interaction measure (MIM), a measure of true interaction constructed from the maximization of imaginary coherency in the virtual channels comprised of voxel signals in source space. Non-zero-phase interactions occurred between homologous left and right hemisphere regions of the DAN in the delta and alpha frequency bands. Even stronger non-zero-phase interactions were detected between networks. Visual regions bilaterally showed phase-shifted interactions in the alpha band with regions of the DAN. Bilateral somatomotor regions interacted with DAN nodes in the beta band. These results demonstrate the existence of consistent, frequency specific phase-shifted interactions on a millisecond time scale between cortical regions within RSN as well as across RSNs. PMID:23631996

  9. Effects of 60-Hz electric fields on serotonin metabolism in the rat pineal gland

    SciTech Connect

    Anderson, L.E.; Hilton, D.I.; Phillips, R.D.; Wilson, B.W.; Chess, E.K.

    1982-06-01

    Serotonin and two of its metabolites, melatonin and 5-methoxytryptophol, exhibit circadian rhythmicity in the pineal gland. We recently reported a marked reduction in the normal night-time increase in melatonin concentration in the pineal glands of rats exposed to 60-Hz electric fields. Concomitant with the apparent abolition of melatonin rhythmicity, serotonin-N-acetyl transferase (SNAT) activity was suppressed. We have now conducted studies to determine if abolition of the rhythm in melatonin production in electric-field-exposed rats arises solely from interference in SNAT activity, or if the availability of pineal serotonin is a factor that is affected by exposure. Pineal serotonin concentrations were compared in rats that were either exposed or sham exposed to 65 kV/m for 30 days. Sham-exposed animals exhibited normal diurnal rhythmicity for pineal concentrations of both melatonin and serotonin; melatonin levels increased markedly during the dark phase with a concurrent decrease in serotonin levels. In the exposed animals, however, normal serotonin rhythmicity was abolished; serotonin levels in these animals did not increase during the light period. The conclusion that electric field exposure results in a biochemical alteration in SNAT enzyme activity can be inferred from the loss of both serotonin and melatonin rhythmicity, as well as by direct measurement of SNAT activity itself. 35 references, 3 figures, 1 table.

  10. The inhibitory and combinative mechanism of HZ08 with P-glycoprotein expressed on the membrane of Caco-2 cell line.

    PubMed

    Zhang, Yanyan; Hu, Yahui; Feng, Yidong; Kodithuwakku, Nandani Darshika; Fang, Weirong; Li, Yunman; Huang, Wenlong

    2014-01-15

    Recently, the research and development of agents to reverse the phenomenon of multidrug resistance has been an attractive goal as well as a key approach to elevating the clinical survival of cancer patients. Although three generations of P-glycoprotein modulators have been identified, poor clearance and metabolism render these agents too toxic to be used in clinical application. HZ08, which has been under investigation for several years, shows a dramatic reversal effect with low cytotoxicity. For the first time, we aimed to describe the interaction between HZ08 and P-glycoprotein in Caco-2 cell line in which P-glycoprotein is overexpressed naturally. Cytotoxicity and multidrug resistance reversal assays, together with flow cytometry, fluorescence microscopy and siRNA interference as well as Caco-2 monolayer transport model were employed in this study to evaluate the interaction between HZ08 and P-glycoprotein. This study revealed that HZ08 was capable of reversing adriamycin resistance mediated by P-glycoprotein as a result of intracellular enhancement of adriamycin accumulation, which was found to be superior to verapamil. In addition, we confirmed that HZ08 suppressed the transport of Rhodamine123 in the Caco-2 monolayer model but had little effect on P-glycoprotein expression. The transport of HZ08 was diminished by P-glycoprotein inhibitors (verapamil and LY335979) and its accumulation was increased via siRNA targeting MDR1 in Caco-2 cells. Furthermore, considering the binding site of P-glycoprotein, verapamil performed as a competitive inhibitor with HZ08. In conclusion, as a P-glycoprotein substrate, HZ08 inhibited P-glycoprotein activity and may share the same binding site of verapamil to P-glycoprotein.

  11. Exploratory Analyses of the Long-Term Effects of Improving Behavior, Attendance, and Educational Achievement in Grades 1-6 and 8-12. ACT Research Report Series, 2012 (3)

    ERIC Educational Resources Information Center

    Sawyer, Richard; Gibson, Neal

    2012-01-01

    We studied relationships among background characteristics, behavioral infractions, punishments, attendance, and educational achievement, using longitudinal data of students in grades 1-6 and 8-12. We estimated how much hypothesized early improvements in educational achievement or sustained improvements in behavior and attendance might ultimately…

  12. 1  J, 0.5  kHz repetition rate picosecond laser.

    PubMed

    Baumgarten, Cory; Pedicone, Michael; Bravo, Herman; Wang, Hanchen; Yin, Liang; Menoni, Carmen S; Rocca, Jorge J; Reagan, Brendan A

    2016-07-15

    We report the demonstration of a diode-pumped chirped pulse amplification Yb:YAG laser that produces λ=1.03  μm pulses of up to 1.5 J energy compressible to sub-5 ps duration at a repetition rate of 500 Hz (750 W average power). Amplification to high energy takes place in cryogenically cooled Yb:YAG active mirrors designed for kilowatt average power laser operation. This compact laser system will enable new advances in high-average-power ultrashort-pulse lasers and high-repetition-rate tabletop soft x-ray lasers. As a first application, the laser was used to pump a 400 Hz λ=18.9  nm laser. PMID:27420530

  13. Differential effects on mood of 12-15 (SMR) and 15-18 (beta1) Hz neurofeedback.

    PubMed

    Gruzelier, John H

    2014-07-01

    The common assumption in EEG-neurofeedback is one of functional specificity of the trained spectral bands, though it has been posited that only a nonspecific generalised learning process may be engaged. Earlier we reported differential effects on attention in healthy participants measured with continuous performance tests and the P300, following training of the sensory-motor rhythm band (SMR, 12-15 Hz) compared with the adjacent beta1 (15-18 hz) band. Here previously unreported results are presented with phenomenological data from an activation checklist in support of the putative calming effect of SMR neurofeedback. While within sessions both protocols induced tiredness, this was paralleled by an increase in calmness only following SMR training. The differential effect on mood was theoretically consistent and extends evidence of cognitive functional specificity with neurofeedback to affective processes.

  14. [Selective attention in dogs from energy characteristics of neocortical potentials in the 1-220 Hz band].

    PubMed

    Dumenko, V N; Kozlov, M K; Kulikov, M A

    2001-01-01

    The state of selective attention was studied in dogs in the course of instrumental conditioning. During interstimuli intervals, this state was manifested in the state of strained waiting for conditioned stimuli. Electrical activity of different areas in both hemispheres was analyzed using the Fast Fourier Transformation. It was shown that in the process of development of selective attention, the high-frequency EEG components (40-200 Hz) in the motor area of the right hemisphere and the visual and parietal areas of the left hemisphere had a predominant significance over the traditional EEG frequencies of 1-30 Hz. The state of selective attention was characterized by another functional mosaic organization of the neocortical potentials.

  15. Coherent 25- to 35-Hz Oscillations in the Sensorimotor Cortex of Awake Behaving Monkeys

    NASA Astrophysics Data System (ADS)

    Murthy, Venkatesh N.; Fetz, Eberhard E.

    1992-06-01

    Synchronous 25- to 35-Hz oscillations were observed in local field potentials and unit activity in sensorimotor cortex of awake rhesus monkeys. The oscillatory episodes occurred often when the monkeys retrieved raisins from a Kluver board or from unseen locations using somatosensory feedback; they occurred less often during performance of repetitive wrist flexion and extension movements. The amplitude, duration, and frequency of oscillations were not directly related to movement parameters in behaviors studied so far. The occurrence of the oscillations was not consistently related to bursts of activity in forearm muscles, but cycle-triggered averages of electromyograms revealed synchronous modulation in flexor and extensor muscles. The phase of the oscillations changed continuously from the surface to the deeper layers of the cortex, reversing their polarity completely at depths exceeding 800 μm. The oscillations could become synchronized over a distance of 14 mm mediolaterally in precentral cortex. Coherent oscillations could also occur at pre- and postcentral sites separated by an estimated tangential intracortical distance of 20 mm. Activity of single units was commonly seen to burst in synchrony with field potential oscillations. These findings suggest that such oscillations may facilitate interactions between cells during exploratory and manipulative movements, requiring attention to sensorimotor integration.

  16. Sub-kHz Linewidth GaSb Semiconductor Diode Lasers Operating Near 2 Micrometers

    NASA Technical Reports Server (NTRS)

    Bagheri, Mahmood; Briggs, Ryan M.; Frez, Clifford; Ksendzov, Alexander; Forouhar, Siamak

    2012-01-01

    We report on the phase noise properties of DFB lasers operating near 2.0 microns. Measured noise spectra indicate intrinsic laser linewidths below 1 kHz. An effective linewidth of less than 200 kHz for 5 ms measurement times is estimated.

  17. The 1983-84 Connecticut 45-Hz-band field-strength measurements

    NASA Astrophysics Data System (ADS)

    Bannister, P. R.

    1986-03-01

    Extremely low frequency (ELF) measurements are made of the transverse horizontal magnetic field strength received in Connecticut. The AN/BSR-1 receiver consists of an AN/UYK-20 minicomputer, a signal timing and interface unit (STIU), a rubidium frequency time standard, two magnetic tape recorders, and a preamplifier. The transmission source of these farfield (1.6-Mm range) measurements is the U.S. Navy's ELF Wisconsin Test Facility (WTF), located in the Chequamegon National Forest in north central Wisconsin, about 8 km south of the village of Clam Lake. The WTF consists of two 22.5-km antennas; one of which is situated approximately in the north-south (NS) direction and the other approximately in the east-west (EW) direction. Each antenna is grounded at both ends. The electrical axis of the WTF EW antenna is 11 deg east of north at 45 Hz and 14 deg east of north at 75Hz. The electrical axis of the WTF NS antenna is 11 deg east of north at 45 Hz and 14 deg east of north at 75 Hz. The WTF array can be steered electrically. Its radiated power is approximately 0.5 W at 45 Hz and 1 W at 75 Hz. This report will compare results of 45 Hz band data taken during 1983 to 1984 with previous 45 Hz band measurements.

  18. Development and testing of a 20-kHz component test bed

    NASA Technical Reports Server (NTRS)

    Button, Robert M.; Brush, Andrew S.; Sundberg, Richard C.

    1989-01-01

    A history of the General Dynamics Space Systems Division 20 kHz Breadboard is presented including its current configuration and its role in the Space Station Freedom (SSF) program. Highlights and results are presented on a series of tests conducted on the 20 kHz Breadboard. The first test presented is the 20 kHz Breadboard Acceptance test. This test verified the operation of the delivered Breadboard and also characterized the main components of the system. Next, an indepth efficiency testing effort is presented. The tests attempted to apportion all the power losses in the 20 kHz Breadboard Main Invert Units. Distortion test data is presented showing the distortion characteristics of a Mapham inverter. Lastly, current work on the 20 kHz Breadboard is presented including Main Inverter Unit paralleling tests. Conclusions are summarized and references given.

  19. Further studies of 60 Hz exposure effects on human function

    SciTech Connect

    Graham, C.; Cohen, H.D.

    1990-10-09

    Public concern has been expressed about possible health risks arising from exposure to the electric and magnetic fields generated power distribution systems. This project is addressing this concern through a laboratory research program designed to evaluate the effects of brief exposure to known field conditions on multiple measures of human function. In previous research, we found that exposure had statistically significant effects on physiological measures of cardiac and brain activity, and on performance measures of reaction time and performance accuracy. Effects were seen more clearly under intermittent exposure conditions, and at certain levels of electric and magnetic field strength. In this continuation effort, we are performing a series of exploratory studies, to be followed by a confirmatory experiment, to determine if the above physiological effects differ as a function of exposure to the electric and magnetic fields separately and combined, time of day, and rate of intermittent exposure. Further studies will explore the mechanisms underlying these effects. The information developed in this project will be of value in risk assessment activities, and in basic research aimed at identifying specific factors involved in the interaction of power line fields with the human system. In this reporting period our goals were to: (a) continue performance of the probe studies; (b) participate in a site visit at MRI; (c) request 1991 research continuation funding; and (d) submit an abstract of project findings for presentation at the 1990 DOE Contractors Review Meeting.

  20. Human exposure standards in the frequency range 1 Hz To 100 kHz: the case for adoption of the IEEE standard.

    PubMed

    Patrick Reilly, J

    2014-10-01

    Differences between IEEE C95 Standards (C95.6-2002 and C95.1-2005) in the low-frequency (1 Hz-100 kHz) and the ICNIRP-2010 guidelines appear across the frequency spectrum. Factors accounting for lack of convergence include: differences between the IEEE standards and the ICNIRP guidelines with respect to biological induction models, stated objectives, data trail from experimentally derived thresholds through physical and biological principles, selection and justification of safety/reduction factors, use of probability models, compliance standards for the limbs as distinct from the whole body, defined population categories, strategies for central nervous system protection below 20 Hz, and correspondence of environmental electric field limits with contact currents. This paper discusses these factors and makes the case for adoption of the limits in the IEEE standards.

  1. A reference-beam autocollimator with nanoradian sensitivity from mHz to kHz and dynamic range of 107

    NASA Astrophysics Data System (ADS)

    Arp, T. B.; Hagedorn, C. A.; Schlamminger, S.; Gundlach, J. H.

    2013-09-01

    We describe an autocollimating optical angle sensor with a dynamic range of 9 mrad and nrad/sqrt{textrm {Hz}} sensitivity at frequencies from 5 mHz to 3 kHz. This work improves the standard multi-slit autocollimator design by adding two optical components, a reference mirror and a condensing lens. This autocollimator makes a differential measurement between a reference mirror and a target mirror, suppressing common-mode noise sources. The condensing lens reduces optical aberrations, increases intensity, and improves image quality. To further improve the stability of the device at low frequencies the body of the autocollimator is designed to reduce temperature variations and their effects. A new data processing technique was developed in order to suppress the effects of imperfections in the CCD.

  2. A reference-beam autocollimator with nanoradian sensitivity from mHz to kHz and dynamic range of 10(7).

    PubMed

    Arp, T B; Hagedorn, C A; Schlamminger, S; Gundlach, J H

    2013-09-01

    We describe an autocollimating optical angle sensor with a dynamic range of 9 mrad and nrad/√Hz sensitivity at frequencies from 5 mHz to 3 kHz. This work improves the standard multi-slit autocollimator design by adding two optical components, a reference mirror and a condensing lens. This autocollimator makes a differential measurement between a reference mirror and a target mirror, suppressing common-mode noise sources. The condensing lens reduces optical aberrations, increases intensity, and improves image quality. To further improve the stability of the device at low frequencies the body of the autocollimator is designed to reduce temperature variations and their effects. A new data processing technique was developed in order to suppress the effects of imperfections in the CCD.

  3. High-anxiety rats are less sensitive to the rewarding affects of amphetamine on 50kHz USV.

    PubMed

    Lehner, Małgorzata H; Taracha, Ewa; Kaniuga, Ewelina; Wisłowska-Stanek, Aleksandra; Wróbel, Jacek; Sobolewska, Alicja; Turzyńska, Danuta; Skórzewska, Anna; Płaźnik, Adam

    2014-12-15

    This study assessed behaviour, as measured by 50kHz calls related to positive affect, in rats with different fear conditioned response strengths: low-anxiety rats (LR) and high-anxiety rats (HR), after amphetamine injection in a two-injection protocol (TIPS). The results showed that the first dose of amphetamine evoked similar behavioural effects in frequency-modulated (FM) 50kHz calls in the LR and HR groups. The second injection of amphetamine resulted in stronger FM 50kHz calls in LR compared with HR rats. The biochemical data ('ex vivo' analysis) showed that the LR rats had increased basal levels of dopamine in the amygdala, and increased homovanilic acid (HVA), dopamine's main metabolite, in the amygdala and prefrontal cortex compared with HR rats. The 'in vivo' analysis (microdialysis study) showed that the LR rats had increased HVA concentrations in the basolateral amygdala in response to an aversively conditioned context. Research has suggested that differences in dopaminergic system activity in the amygdala and prefrontal cortex may be one of the biological factors that underlie individual differences in response to fear stimuli, which may also affect the rewarding effects of amphetamine.

  4. Nonuniform High-Gamma (60–500 Hz) Power Changes Dissociate Cognitive Task and Anatomy in Human Cortex

    PubMed Central

    Gaona, Charles M.; Sharma, Mohit; Freudenburg, Zachary V.; Breshears, Jonathan D.; Bundy, David T.; Roland, Jarod; Barbour, Dennis L.; Schalk, Gerwin

    2011-01-01

    High-gamma-band (>60 Hz) power changes in cortical electrophysiology are a reliable indicator of focal, event-related cortical activity. Despite discoveries of oscillatory subthreshold and synchronous suprathreshold activity at the cellular level, there is an increasingly popular view that high-gamma-band amplitude changes recorded from cellular ensembles are the result of asynchronous firing activity that yields wideband and uniform power increases. Others have demonstrated independence of power changes in the low- and high-gamma bands, but to date, no studies have shown evidence of any such independence above 60 Hz. Based on nonuniformities in time-frequency analyses of electrocorticographic (ECoG) signals, we hypothesized that induced high-gamma-band (60–500 Hz) power changes are more heterogeneous than currently understood. Using single-word repetition tasks in six human subjects, we showed that functional responsiveness of different ECoG high-gamma sub-bands can discriminate cognitive task (e.g., hearing, reading, speaking) and cortical locations. Power changes in these sub-bands of the high-gamma range are consistently present within single trials and have statistically different time courses within the trial structure. Moreover, when consolidated across all subjects within three task-relevant anatomic regions (sensorimotor, Broca's area, and superior temporal gyrus), these behavior- and location-dependent power changes evidenced nonuniform trends across the population. Together, the independence and nonuniformity of power changes across a broad range of frequencies suggest that a new approach to evaluating high-gamma-band cortical activity is necessary. These findings show that in addition to time and location, frequency is another fundamental dimension of high-gamma dynamics. PMID:21307246

  5. Interferometric readout of a monolithic accelerometer, towards the fm /√{ Hz } resolution

    NASA Astrophysics Data System (ADS)

    van Heijningen, J. V.; Bertolini, A.; van den Brand, J. F. J.

    2016-07-01

    The European Gravitational wave Observatory Virgo is undergoing an upgrade to increase its strain sensitivity to about 3 ×10-24 1 /√{ Hz } in the detection band of 10 Hz-10 kHz. The upgrade for this detector necessitates seismically isolating sensing optics in a vacuum environment that were on an optical bench outside vacuum in previous Virgo configurations. For this purpose, Nikhef has designed and built the five compact isolators, called MultiSAS. To measure the residual motion of the optical components and the transfer function of the isolator in full assembly, no (commercial) sensor is available that has sufficient sensitivity. A novel vibration sensor has been built at Nikhef that features an interferometric readout for a horizontal monolithic accelerometer. It will be able to measure in the vicinity of the fm/Hz regime from 10 Hz onwards. Current results show unprecedented (self) noise levels around 35 fm/Hz from 25 Hz onwards. In spite of these excellent results, it is still higher than the modeled noises. Several possible unmodeled noise sources and possible solutions have been identified.

  6. Low potency and limited efficacy of antiepileptic drugs in the mouse 6 Hz corneal kindling model.

    PubMed

    Leclercq, K; Matagne, A; Kaminski, R M

    2014-05-01

    Corneal kindling is a useful alternative to electrically induced amygdala or hippocampal kindling, which requires advanced surgical and EEG techniques that may not be easily available in many laboratories. Therefore the first aim of this study was to evaluate whether repeated 6 Hz corneal stimulation in mice would lead to an increased and persistent seizure response as described for higher frequency (50/60 Hz) corneal kindling. Male NMRI mice stimulated twice daily (except weekends) for 3 s with 6 Hz electrical current at 44 mA displayed robust kindling development, i.e., a progressive increase in seizure severity. The majority of the animals (about 90%) developed a fully kindled state, defined as at least 10 consecutive stage 3-5 seizures within 5 weeks of corneal stimulation. Afterwards, the fully kindled state was maintained for at least 8 weeks with only two days of stimulations per week. Next, the protective efficacy of four mechanistically different antiepileptic drugs (AEDs; clonazepam, valproate, carbamazepine and levetiracetam) was assessed and compared between 6 Hz and 50 Hz fully kindled mice. All tested AEDs showed a relatively lower potency in the 6 Hz kindling model and a limited efficacy against partial seizures was observed with carbamazepine and levetiracetam. We can conclude that 6 Hz kindling may be more advantageous than the previously described 50/60 Hz corneal kindling models due to its robustness and persistence of the fully kindled state. Furthermore, the observed low potency and limited efficacy of AEDs in 6 Hz fully kindled mice suggest that this model could be a useful tool in the discovery of novel AEDs targeting treatment resistant epilepsy.

  7. Air puff-induced 22-kHz calls in F344 rats.

    PubMed

    Inagaki, Hideaki; Sato, Jun

    2016-03-01

    Air puff-induced ultrasonic vocalizations in adult rats, termed "22-kHz calls," have been applied as a useful animal model to develop psychoneurological and psychopharmacological studies focusing on human aversive affective disorders. To date, all previous studies on air puff-induced 22-kHz calls have used outbred rats. Furthermore, newly developed gene targeting technologies, which are essential for further advancement of biomedical experiments using air puff-induced 22-kHz calls, have enabled the production of genetically modified rats using inbred rat strains. Therefore, we considered it necessary to assess air puff-induced 22-kHz calls in inbred rats. In this study, we assessed differences in air puff-induced 22-kHz calls between inbred F344 rats and outbred Wistar rats. Male F344 rats displayed similar total (summed) duration of air puff-induced 22 kHz vocalizations to that of male Wistar rats, however, Wistar rats emitted fewer calls of longer duration, while F344 rats emitted higher number of vocalizations of shorter duration. Additionally, female F344 rats emitted fewer air puff-induced 22-kHz calls than did males, thus confirming the existence of a sex difference that was previously reported for outbred Wistar rats. The results of this study could confirm the reliability of air puff stimulus for induction of a similar amount of emissions of 22-kHz calls in different rat strains, enabling the use of air puff-induced 22-kHz calls in inbred F344 rats and derived genetically modified animals in future studies concerning human aversive affective disorders.

  8. Benefits of 20 kHz PMAD in a nuclear space station

    NASA Astrophysics Data System (ADS)

    Sundberg, Gale R.

    Compared to existing systems, high frequency ac power provides higher efficiency, lower cost, and improved safety benefits. The 20 kHz power system has exceptional flexibility, is inherently user friendly, and is compatible with all types of energy sources; photovoltaic, solar dynamic, rotating machines and nuclear. A 25 kW, 20 kHz ac power distribution system testbed was recently (1986) developed. The testbed possesses maximum flexibility, versatility, and transparency to user technology while maintaining high efficiency, low mass, and reduced volume. Several aspects of the 20 kHz power management and distribution (PMAD) system that have particular benefits for a nuclear power Space Station are discussed.

  9. Benefits of 20 kHz PMAD in a nuclear space station

    NASA Technical Reports Server (NTRS)

    Sundberg, Gale R.

    1987-01-01

    Compared to existing systems, high frequency ac power provides higher efficiency, lower cost, and improved safety benefits. The 20 kHz power system has exceptional flexibility, is inherently user friendly, and is compatible with all types of energy sources; photovoltaic, solar dynamic, rotating machines and nuclear. A 25 kW, 20 kHz ac power distribution system testbed was recently (1986) developed. The testbed possesses maximum flexibility, versatility, and transparency to user technology while maintaining high efficiency, low mass, and reduced volume. Several aspects of the 20 kHz power management and distribution (PMAD) system that have particular benefits for a nuclear power Space Station are discussed.

  10. Functional roles of 10 Hz alpha-band power modulating engagement and disengagement of cortical networks in a complex visual motion task.

    PubMed

    Rana, Kunjan D; Vaina, Lucia M

    2014-01-01

    Alpha band power, particularly at the 10 Hz frequency, is significantly involved in sensory inhibition, attention modulation, and working memory. However, the interactions between cortical areas and their relationship to the different functional roles of the alpha band oscillations are still poorly understood. Here we examined alpha band power and the cortico-cortical interregional phase synchrony in a psychophysical task involving the detection of an object moving in depth by an observer in forward self-motion. Wavelet filtering at the 10 Hz frequency revealed differences in the profile of cortical activation in the visual processing regions (occipital and parietal lobes) and in the frontoparietal regions. The alpha rhythm driving the visual processing areas was found to be asynchronous with the frontoparietal regions. These findings suggest a decoupling of the 10 Hz frequency into separate functional roles: sensory inhibition in the visual processing regions and spatial attention in the frontoparietal regions.

  11. 5 Hz, >250 mJ Optical Parametric Chirped-Pulse Amplifier at 1053 nm

    SciTech Connect

    Bagnoud, V.; Begishev, I.A.; Guardalben, M.J.; Puth, J.; Zuegel, J.D.

    2005-07-15

    A 250 mJ, 5 Hz repetition rate optical parametric chirped-pulse amplifier with near-Fourier-transform-limited, 430 fs pulses and a beam that can be focused to near the diffraction limit is demonstrated.

  12. Effects of 60 Hz electric fields on operant and social stress behaviors of nonhuman primates

    SciTech Connect

    Rogers, W.R.; Lucas, J.H.; Moore, G.T.; Orr, J.L.

    1985-01-01

    An overall description of this research program is presented. The objectives are to investigate using nonhuman primates, possible behavioral effects associated with exposure to high-intensity, 60 Hz, electric fields. 6 tabs.

  13. Measurement of the acoustic reflectivity of sirenia (Florida manatees) at 171 kHz.

    PubMed

    Jaffe, Jules S; Simonet, Fernando; Roberts, Paul L D; Bowles, Ann E

    2007-01-01

    The Florida manatee (Trichechus manatus latirostris) is an endangered sirenian. At present, its adult population (approximately 2200) seems stable, but tenuous. Manatee-boat collisions are a significant proportion (approximately 25%) of mortalities. Here, the potential use of active sonar for detecting manatees by quantifying sonic reflectivity is explored. In order to estimate reflectivity two methods were used. One method measured live reflections from captive animals using a carefully calibrated acoustic and co-registered optical system. The other method consisted of the analysis of animal tissue in order to obtain estimates of the sound speed and density and to predict reflectivity. The impedance measurement predicts that for a lateral view, the tissue reflectivity is close to 0.13, with a critical grazing angle of 28 degrees. Data measured from live animals indicate that substantial reflections can be recorded, however in many instances observed "empirical target strengths" were less than an experimentally dependent -48-dB threshold. Conclusions favor the hypothesis that the animals reflect substantial amounts of sound; however, the reflections can often be specular, and therefore impractical for observation by a manatee detection sonar operating at 171 kHz. PMID:17297771

  14. Cyclic Stress at mHz Frequencies Aligns Fibroblasts in Direction of Zero Strain

    PubMed Central

    Rubner, Wolfgang; Kirchgeßner, Norbert; Safran, Sam; Hoffmann, Bernd; Merkel, Rudolf

    2011-01-01

    Recognition of external mechanical signals is vital for mammalian cells. Cyclic stretch, e.g. around blood vessels, is one such signal that induces cell reorientation from parallel to almost perpendicular to the direction of stretch. Here, we present quantitative analyses of both, cell and cytoskeletal reorientation of umbilical cord fibroblasts. Cyclic strain of preset amplitudes was applied at mHz frequencies. Elastomeric chambers were specifically designed and characterized to distinguish between zero strain and minimal stress directions and to allow accurate theoretical modeling. Reorientation was only induced when the applied stretch exceeded a specific amplitude, suggesting a non-linear response. However, on very soft substrates no mechanoresponse occurs even for high strain. For all stretch amplitudes, the angular distributions of reoriented cells are in very good agreement with a theory modeling stretched cells as active force dipoles. Cyclic stretch increases the number of stress fibers and the coupling to adhesions. We show that changes in cell shape follow cytoskeletal reorientation with a significant temporal delay. Our data identify the importance of environmental stiffness for cell reorientation, here in direction of zero strain. These in vitro experiments on cultured cells argue for the necessity of rather stiff environmental conditions to induce cellular reorientation in mammalian tissues. PMID:22194961

  15. Measurement of the acoustic reflectivity of sirenia (Florida manatees) at 171 kHz.

    PubMed

    Jaffe, Jules S; Simonet, Fernando; Roberts, Paul L D; Bowles, Ann E

    2007-01-01

    The Florida manatee (Trichechus manatus latirostris) is an endangered sirenian. At present, its adult population (approximately 2200) seems stable, but tenuous. Manatee-boat collisions are a significant proportion (approximately 25%) of mortalities. Here, the potential use of active sonar for detecting manatees by quantifying sonic reflectivity is explored. In order to estimate reflectivity two methods were used. One method measured live reflections from captive animals using a carefully calibrated acoustic and co-registered optical system. The other method consisted of the analysis of animal tissue in order to obtain estimates of the sound speed and density and to predict reflectivity. The impedance measurement predicts that for a lateral view, the tissue reflectivity is close to 0.13, with a critical grazing angle of 28 degrees. Data measured from live animals indicate that substantial reflections can be recorded, however in many instances observed "empirical target strengths" were less than an experimentally dependent -48-dB threshold. Conclusions favor the hypothesis that the animals reflect substantial amounts of sound; however, the reflections can often be specular, and therefore impractical for observation by a manatee detection sonar operating at 171 kHz.

  16. Research Needs for Magnetic Fusion Energy Sciences. Report of the Research Needs Workshop (ReNeW) Bethesda, Maryland, June 8-12, 2009

    SciTech Connect

    2009-06-08

    Nuclear fusion - the process that powers the sun - offers an environmentally benign, intrinsically safe energy source with an abundant supply of low-cost fuel. It is the focus of an international research program, including the ITE R fusion collaboration, which involves seven parties representing half the world's population. The realization of fusion power would change the economics and ecology of energy production as profoundly as petroleum exploitation did two centuries ago. The 21st century finds fusion research in a transformed landscape. The worldwide fusion community broadly agrees that the science has advanced to the point where an aggressive action plan, aimed at the remaining barriers to practical fusion energy, is warranted. At the same time, and largely because of its scientific advance, the program faces new challenges; above all it is challenged to demonstrate the timeliness of its promised benefits. In response to this changed landscape, the Office of Fusion Energy Sciences (OFES ) in the US Department of Energy commissioned a number of community-based studies of the key scientific and technical foci of magnetic fusion research. The Research Needs Workshop (ReNeW) for Magnetic Fusion Energy Sciences is a capstone to these studies. In the context of magnetic fusion energy, ReNeW surveyed the issues identified in previous studies, and used them as a starting point to define and characterize the research activities that the advance of fusion as a practical energy source will require. Thus, ReNeW's task was to identify (1) the scientific and technological research frontiers of the fusion program, and, especially, (2) a set of activities that will most effectively advance those frontiers. (Note that ReNeW was not charged with developing a strategic plan or timeline for the implementation of fusion power.) This Report presents a portfolio of research activities for US research in magnetic fusion for the next two decades. It is intended to provide a

  17. Aging and the 4-kHz Air-Bone Gap

    ERIC Educational Resources Information Center

    Nondahl, David M.; Tweed, Ted S.; Cruickshanks, Karen J.; Wiley, Terry L.; Dalton, Dayna S.

    2012-01-01

    Purpose: In this study, the authors assessed age- and sex-related patterns in the prevalence and 10-year incidence of 4-kHz air-bone gaps and associated factors. Method: Data were obtained as part of the longitudinal, population-based Epidemiology of Hearing Loss Study ( Cruickshanks et al., 1998). An air-bone gap at 4 kHz was defined as an…

  18. The Modified HZ Conjugate Gradient Algorithm for Large-Scale Nonsmooth Optimization

    PubMed Central

    Yuan, Gonglin; Sheng, Zhou; Liu, Wenjie

    2016-01-01

    In this paper, the Hager and Zhang (HZ) conjugate gradient (CG) method and the modified HZ (MHZ) CG method are presented for large-scale nonsmooth convex minimization. Under some mild conditions, convergent results of the proposed methods are established. Numerical results show that the presented methods can be better efficiency for large-scale nonsmooth problems, and several problems are tested (with the maximum dimensions to 100,000 variables). PMID:27780245

  19. Antiadipogenic effects of subthermal electric stimulation at 448 kHz on differentiating human mesenchymal stem cells

    PubMed Central

    HERNÁNDEZ-BULE, MARÍA LUISA; MARTÍNEZ-BOTAS, JAVIER; TRILLO, MARÍA ÁNGELES; PAÍNO, CARLOS L; ÚBEDA, ALEJANDRO

    2016-01-01

    The 448 kHz capacitive-resistive electric transfer (CRET) is an electrothermal therapy currently applied in anticellulite and antiobesity treatments. The aim of the present study was to determine whether exposure to the CRET electric signal at subthermal doses affected early adipogenic processes in adipose-derived stem cells (ADSC) from human donors. ADSC were incubated for 2 or 9 days in the presence of adipogenic medium, and exposed or sham-exposed to 5 min pulses of 448 kHz electric signal at 50 µA/mm2 during the last 48 h of the incubation. Colorimetric, immunofluorescence, western blotting and reverse transcription-quantitative polymerase chain reaction assays were performed to assess adipogenic differentiation of the ADSC. Electric stimulation significantly decreased cytoplasmic lipid content, after both 2 and 9 days of differentiation. The antiadipogenic response in the 9 day samples was accompanied by activation of mitogen-activated protein kinase kinase 1/2, decreased expression and partial inactivation of peroxisome proliferator-activated receptor (PPAR) γ, which was translocated from the nucleus to the cytoplasm, together with a significant decrease in the expression levels of the PPARG1 gene, perilipin, angiopoietin-like protein 4 and fatty acid synthase. These results demonstrated that subthermal stimulation with CRET interferes with the early adipogenic differentiation in ADSC, indicating that the electric stimulus itself can modulate processes controlling the synthesis and mobilization of fat, even in the absence of the concomitant thermal and mechanical components of the thermoelectric therapy CRET. PMID:27035334

  20. Anticipatory 50 kHz ultrasonic vocalizations are associated with escalated alcohol intake in dependent rats

    PubMed Central

    Buck, Cara L.; Malavar, Jordan C.; George, Olivier; Koob, George F.; Vendruscolo, Leandro F.

    2014-01-01

    Rats emit 50 kHz ultrasonic vocalizations (USVs) in situations of increased motivation, such as during the anticipation of palatable food or drugs of abuse. Whether the same holds true for the anticipation of alcohol intake remains unknown. Alcohol drinking in a nondependent state is thought to be mediated by its rewarding effects (positive reinforcement), whereas drinking in the dependent state is motivated by alcohol’s stress-relieving effects (negative reinforcement). Here, we measured context-elicited 50 kHz USVs in alcohol-dependent (alcohol vapor-exposed) and nondependent rats immediately before operant alcohol self-administration sessions. Dependent rats showed escalated levels of alcohol intake compared with nondependent rats. Overall, dependent and nondependent rats showed similar levels of anticipatory 50 kHz USVs. However, the number of anticipatory USVs was positively correlated with alcohol intake in dependent rats but not nondependent rats. Additionally, dependent rats with higher alcohol intake displayed increased anticipatory 50 kHz USVs compared with rats that had lower alcohol intake, whereas no difference was observed between rats with high and low alcohol intake in the nondependent group. Increased 50 kHz USVs were specific for the anticipation of alcohol self-administration and did not generalize to a novel environment. These findings suggest that anticipatory 50 kHz USVs may be an indicator of context-elicited negative reinforcement learning. PMID:24914463

  1. An extrasolar extreme-ultraviolet object. II - The nature of HZ 43. [hot white dwarf star

    NASA Technical Reports Server (NTRS)

    Margon, B.; Liebert, J.; Lampton, M.; Spinrad, H.; Bowyer, S.; Gatewood, G.

    1976-01-01

    A variety of data are presented concerning the spectrum, distance, temperature, and evolutionary state of the hot white dwarf HZ 43, the first extrasolar object to be detected in the EUV band. The data include spectrophotometry of the star and its red dwarf companion (HZ 43B), a trigonometric parallax for the star, its tangential velocity, and results of soft X-ray and EUV observations. The main conclusions are that: (1) the spectrum of HZ 43A is that of a hot DAwk star, (2) HZ 43B is a dM3.5e star, (3) the distance of the system is about 65 pc, (4) the tangential velocity is not atypical of white dwarfs, and (5) the stellar energy distribution of HZ 43A is well fitted by a black body with an effective temperature of approximately 110,000 K. Evolutionary implications of the existence of an object as hot as HZ 43A are briefly considered, and it is suggested that the progenitors of hot DA stars must include objects hotter than spectral type sdB, with logical possibilities being nuclei of planetary nebulae and sdO stars.

  2. Temporary threshold shifts and recovery in a harbor porpoise (Phocoena phocoena) after octave-band noise at 4 kHz.

    PubMed

    Kastelein, Ronald A; Gransier, Robin; Hoek, Lean; Olthuis, Juul

    2012-11-01

    Safety criteria for underwater sound produced during offshore pile driving are needed to protect marine mammals. A harbor porpoise was exposed to fatiguing noise at 18 sound pressure level (SPL) and duration combinations. Its temporary hearing threshold shift (TTS) and hearing recovery were quantified with a psychoacoustic technique. Octave-band white noise centered at 4 kHz was the fatiguing stimulus at three mean received SPLs (124, 136, and 148 dB re 1 μPa) and at six durations (7.5, 15, 30, 60, 120, and 240 min). Approximate received sound exposure levels (SELs) varied between 151 and 190 dB re 1 μPa(2) s. Hearing thresholds were determined for a narrow-band frequency-swept sine wave (3.9-4.1 kHz; 1 s) before exposure to the fatiguing noise, and at 1-4, 4-8, 8-12, 48, and 96 min after exposure. The lowest SEL (151 dB re 1 μPa(2) s) which caused a significant TTS(1-4) was due to exposure to an SPL of 124 dB re 1 μPa for 7.5 min. The maximum TTS(1-4), induced after a 240 min exposure to 148 dB re 1 μPa, was around 15 dB at a SEL of 190 dB re 1 μPa(2) s. Recovery time following TTS varied between 4 min and under 96 min, depending on the exposure level, duration, and the TTS induced. PMID:23145632

  3. Glacier Change and Biologic Succession: a new Alaska Summer Research Academy (ASRA) Science Camp Module for Grades 8-12 in Glacier Bay National Park, Alaska

    NASA Astrophysics Data System (ADS)

    Connor, C. L.; Drake, J.; Good, C.; Fatland, R.; Hakala, M.; Woodford, R.; Donohoe, R.; Brenner, R.; Moriarty, T.

    2008-12-01

    During the summer of 2008, university faculty and instructors from southeast Alaska joined the University Alaska Fairbanks(UAF)Alaska Summer Research Academy(ASRA)to initiate a 12-day module on glacier change and biologic succession in Glacier Bay National Park. Nine students from Alaska, Colorado, Massachusetts, and Texas, made field observations and collected data while learning about tidewater glacier dynamics, plant succession, post-glacial uplift, and habitat use of terrestrial and marine vertebrates and invertebrates in this dynamic landscape that was covered by 6,000 km2 of ice just 250 years ago. ASRA students located their study sites using GPS and created maps in GIS and GOOGLE Earth. They deployed salinometers and temperature sensors to collect vertical profiles of seawater characteristics up-bay near active tidewater glacier termini and down-bay in completely deglaciated coves. ASRA student data was then compared with data collected during the same time period by Juneau undergraduates working on the SEAMONSTER project in Mendenhall Lake. ASRA students traversed actively forming, up-bay recessional moraines devoid of vegetation, and the fully reforested Little Ice Age terminal moraine near Park Headquarters in the lower bay region. Students surveyed marine organisms living between supratidal and subtidal zones near glaciers and far from glaciers, and compared up-bay and down-bay communities. Students made observations and logged sightings of bird populations and terrestrial mammals in a linear traverse from the bay's northwestern most fjord near Mt. Fairweather for 120 km to the bay's entrance, south of Park Headquarters at Bartlett Cove. One student constructed an ROV and was able to deploy a video camera and capture changing silt concentrations in the water column as well as marine life on the fjord bottom. Students also observed exhumed Neoglacial spruce forests and visited outcrops of Silurian reef faunas, now fossilized in Alexander terrane

  4. Ankle variability is amplified in older adults due to lower EMG power from 30-60 Hz.

    PubMed

    Kwon, MinHyuk; Baweja, Harsimran S; Christou, Evangelos A

    2012-12-01

    The purpose of this study was to determine the neuromuscular mechanisms of the involved muscles that contribute to the greater positional variability at the ankle joint in older adults compared with young adults. Eleven young adults (25.6±4.9 years) and nine older adults (76.9±5.9 years) were asked to accurately match and maintain a horizontal target line with 5° dorsiflexion of their ankle for 20 s. The loads were 5 and 15% of the one repetition maximum load (1 RM). The visual gain was kept constant at 1° for all trials. Positional variability was quantified as the standard deviation (SD) of the detrended position signal. The neural activation of the tibialis anterior and soleus muscles was quantified as the normalized EMG amplitude, power spectrum density (PSD; EMG oscillations) and coactivation of the two muscles. As expected, positional variability was greater in older adults (older: 0.11±0.06° vs. young: 0.04±0.02°; p=.003). The only significant neural difference occurred for the PSD of the tibialis anterior muscle, where young adults exhibited significantly greater power than older adults from 30-60 Hz. The amplified positional variability of ankle joint in older adults was associated with lower power from 30-60 Hz oscillations in the tibialis anterior muscle (r(2)=.3, p=.01). These results provide novel evidence that older adults exhibit greater positional variability with the ankle joint relative to young adults likely due to their inability to activate the tibialis anterior muscle from 30-60 Hz.

  5. Ankle variability is amplified in older adults due to lower EMG power from 30-60 Hz.

    PubMed

    Kwon, MinHyuk; Baweja, Harsimran S; Christou, Evangelos A

    2012-12-01

    The purpose of this study was to determine the neuromuscular mechanisms of the involved muscles that contribute to the greater positional variability at the ankle joint in older adults compared with young adults. Eleven young adults (25.6±4.9 years) and nine older adults (76.9±5.9 years) were asked to accurately match and maintain a horizontal target line with 5° dorsiflexion of their ankle for 20 s. The loads were 5 and 15% of the one repetition maximum load (1 RM). The visual gain was kept constant at 1° for all trials. Positional variability was quantified as the standard deviation (SD) of the detrended position signal. The neural activation of the tibialis anterior and soleus muscles was quantified as the normalized EMG amplitude, power spectrum density (PSD; EMG oscillations) and coactivation of the two muscles. As expected, positional variability was greater in older adults (older: 0.11±0.06° vs. young: 0.04±0.02°; p=.003). The only significant neural difference occurred for the PSD of the tibialis anterior muscle, where young adults exhibited significantly greater power than older adults from 30-60 Hz. The amplified positional variability of ankle joint in older adults was associated with lower power from 30-60 Hz oscillations in the tibialis anterior muscle (r(2)=.3, p=.01). These results provide novel evidence that older adults exhibit greater positional variability with the ankle joint relative to young adults likely due to their inability to activate the tibialis anterior muscle from 30-60 Hz. PMID:23089330

  6. Adsorption Isotherms for Xenon and Krypton using INL HZ-PAN and AgZ-PAN Sorbents

    SciTech Connect

    Troy G. Garn; Mitchell Greenhalgh; Veronica J. Rutledge; Jack D. Law

    2014-08-01

    The generation of adsorption isotherms compliments the scale-up of off-gas processes used to control the emission of encapsulated radioactive volatile fission and activation products released during Used Nuclear Fuel (UNF) reprocessing activities. A series of experiments were conducted to obtain capacity results for varying Kr and Xe gas concentrations using HZ-PAN and AgZ-PAN engineered form sorbents. Gas compositions for Kr ranged from 150-40,000 ppmv and 250-5020 ppmv for Xe in a helium balance. The experiments were all performed at 220 K at a flowrate of 50 sccm. Acquired capacities were then respectively fit to the Langmuir equation using the Langmuir linear regression method to obtain the equilibrium parameters Qmax and Keq. Generated experimental adsorption isotherms were then plotted with the Langmuir predicted isotherms to illustrate agreement between the two. The Langmuir parameters were provided for input into the OSPREY model to predict breakthrough of single component adsorption of Kr and Xe on HZ-PAN and AgZ-PAN sorbents at the experimental conditions tested. Kr and Xe capacities resulting from model breakthrough predictions were then compared to experimental capacities for model validation.

  7. 47 CFR 73.30 - Petition for authorization of an allotment in the 1605-1705 kHz band.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the 1605-1705 kHz band. 73.30 Section 73.30 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... authorization of an allotment in the 1605-1705 kHz band. (a) Any party interested in operating an AM broadcast station on one of the ten channels in the 1605-1705 kHz band must file a petition for the establishment...

  8. 47 CFR 73.30 - Petition for authorization of an allotment in the 1605-1705 kHz band.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... the 1605-1705 kHz band. 73.30 Section 73.30 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... authorization of an allotment in the 1605-1705 kHz band. (a) Any party interested in operating an AM broadcast station on one of the ten channels in the 1605-1705 kHz band must file a petition for the establishment...

  9. Clinical progression of transplanted large granular lymphocytic leukemia in Fischer 334 rats exposed to 60 Hz magnetic fields

    SciTech Connect

    Morris, James E. ); Sasser, Lyle B. ); Miller, Douglas L. ); Dagle, Gerald E.; Rafferty, C N.; Ebi, K L.; Anderson, Larry E. )

    1999-01-19

    The purpose of this study was to determine if 60 Hz magnetic fields could alter the clinical progression of leukemia in an animal model. Large granular lymphocytic (LGL) leukemia cells from spleens of leukemic rats were transplanted into young male Fischer rats, producing signs of leukemia in about 2-3 months. The animals were injected with 2.2 x 107 LGL leukemia cells at the initiation of the study and assigned to 4 treatment groups 108/group) as follows: (1) 10 G linearly polarized 60 Hz magnetic fields, (2) sham exposed null energized unit with residual 20 mG fields, (3) ambient controls < 1 mG, and (4) positive controls (a single 5 Gy whole body exposure to 60Co 4 days prior to initiation of exposure). The magnetic fields were activated 20h/day, 7 days/week. Eighteen Rats (18 from each treatment group) were bled, killed, and evaluated at a5, 6, 7, 8, 9, and 11 weeks of exposure. Hematological endpoints, changes in spleen growth, and LGL cell infiltration into the spleen and liver were measured to evaluate the leukemia progression. Significant differences were not detected between the magnetic field exposed groups and the ambient control group, although the clinical progress of leukemia was enhanced in the positive control animals. These data indicate that exposure to sinusoidal, linearly polarized 60 Hz, 10 G magnetic fields did not significantly alter the clinical progression of LGL leukemia. Furthermore, the data are in general agreement with previous results of a companion repeated-bleeding study.

  10. Monochromatic ultra-slow (~0.1 Hz) oscillations in the human electroencephalogram and their relation to hemodynamics.

    PubMed

    Nikulin, Vadim V; Fedele, Tommaso; Mehnert, Jan; Lipp, Axel; Noack, Cornelia; Steinbrink, Jens; Curio, Gabriel

    2014-08-15

    Previous studies demonstrated the presence of Monochromatic Ultra-Slow Oscillations (MUSO) in human EEG. In the present study we explored the biological origin of MUSO by simultaneous recordings of EEG, Near-Infrared Spectroscopy (NIRS), arterial blood pressure, respiration and Laser Doppler flowmetry. We used a head-up tilt test in order to check whether MUSO might relate to Mayer waves in arterial blood pressure, known to be enhanced by the tilting procedure. MUSO were detected in 8 out of 10 subjects during rest and showed a striking monochromatic spectrum (0.07-0.14 Hz). The spatial topography of MUSO was complex, showing multiple foci variable across subjects. While the head-up tilt test increased the relative power of Mayer waves, it had no effect on MUSO. On the other hand, the relative spectral power of 0.1 Hz oscillations in EEG, NIRS and blood pressure signals were positively correlated across subjects in the tilted condition. Eight subjects showed a coherence between MUSO and NIRS/arterial blood pressure. Moreover, MUSO at different electrode sites demonstrated coherence not reducible to volume conduction, thus indicating that MUSO are unlikely to be generated by one source. We related our experimental findings to known biological phenomena being generated at about 0.1 Hz, i.e.: arterial blood pressure, cerebral and skin vasomotion, respiration and neuronal activity. While no definite conclusion can yet be drawn as to an exact physiological mechanism of MUSO, we suggest that these oscillations might be of a rather extraneuronal origin reflecting cerebral vasomotion. PMID:24732648

  11. Feasibility of a bilateral 4000–6000 Hz notch as a phenotype for genetic association analysis

    PubMed Central

    Phillips, Susan L.; Richter, Scott J.; Teglas, Sandra L.; Bhatt, Ishan S.; Morehouse, Robin C.; Hauser, Elizabeth R.; Henrich, Vincent C.

    2016-01-01

    Objective Noise-induced hearing loss (NIHL) is a worldwide health problem and a growing concern among young people. Although some people appear to be more susceptible to NIHL, genetic association studies lack a specific phenotype. We tested the feasibility of a bilateral 4000–6000 Hz audiometric notch as a phenotype for identifying genetic contributions to hearing loss in young adults. Design A case-control-control study was conducted to examine selected SNPs in 52 genes previously associated with hearing loss and/or expressed in the cochlea. A notch was defined as a minimum of a 15-dB drop at 4000–6000 Hz from the previous best threshold with a 5-dB ‘recovery’ at 8000 Hz. Study sample Participants were 252 individuals of European descent taken from a population of 640 young adults who are students of classical music. Participants were grouped as No-notch (NN), Unilateral Notch (UN), or Bilateral Notch (BN). Results The strongest evidence of a genetic association with the 4000–6000 Hz notch was a nonsynonymous SNP variant in the ESRR? gene (rs61742642:C>T, P386S). Carriers of the minor allele accounted for 26% of all bilateral losses. Conclusion This study indicates that the 4000–6000 Hz bilateral notch is a feasible phenotype for identifying genetic susceptibility to hearing loss. PMID:25938503

  12. Free-field calibration of measurement microphones at frequencies up to 80 kHz

    NASA Astrophysics Data System (ADS)

    Zuckerwar, Allan J.; Herring, Gregory C.

    2002-11-01

    Civil-aviation noise-reduction programs, that make use of scaled-down aircraft models in wind tunnel tests, require knowledge of microphone pressure (i.e., not free-field) sensitivities beyond 20 kHz--since noise wavelengths also scale down with decreasing model size. Furthermore, not all microphone types (e.g., electrets) are easily calibrated with the electrostatic technique, while enclosed cavity calibrations typically have an upper limit for the useful frequency range. Thus, work was initiated to perform a high-frequency pressure calibration of Panasonic electret microphones using a substitution free-field method in a small anechoic chamber. First, a standard variable-frequency pistonphone was used to obtain the pressure calibration up to 16 kHz. Above 16 kHz, to avoid spatially irregular sound fields due to dephasing of loudspeaker diaphragms, a series of resonant ceramic piezoelectric crystals was used at five specific ultrasonic frequencies as the free-field calibration sound source. Then, the free-field sensitivity was converted to a pressure sensitivity with an electrostatic calibration of the reference microphone (an air condenser type), for which the free-field correction is known. Combining the low- and high-frequency data sets, a full frequency calibration of pressure sensitivity for an electret microphone was generated from 63 Hz to 80 kHz.

  13. Shaping prestimulus neural activity with auditory rhythmic stimulation improves the temporal allocation of attention

    PubMed Central

    Pincham, Hannah L.; Cristoforetti, Giulia; Facoetti, Andrea; Szűcs, Dénes

    2016-01-01

    Human attention fluctuates across time, and even when stimuli have identical physical characteristics and the task demands are the same, relevant information is sometimes consciously perceived and at other times not. A typical example of this phenomenon is the attentional blink, where participants show a robust deficit in reporting the second of two targets (T2) in a rapid serial visual presentation (RSVP) stream. Previous electroencephalographical (EEG) studies showed that neural correlates of correct T2 report are not limited to the RSVP period, but extend before visual stimulation begins. In particular, reduced oscillatory neural activity in the alpha band (8-12 Hz) before the onset of the RSVP has been linked to lower T2 accuracy. We therefore examined whether auditory rhythmic stimuli presented at a rate of 10 Hz (within the alpha band) could increase oscillatory alpha-band activity and improve T2 performance in the attentional blink time window. Behaviourally, the auditory rhythmic stimulation worked to enhance T2 accuracy. This enhanced perception was associated with increases in the posterior T2-evoked N2 component of the event-related potentials and this effect was observed selectively at lag 3. Frontal and posterior oscillatory alpha-band activity was also enhanced during auditory stimulation in the pre-RSVP period and positively correlated with T2 accuracy. These findings suggest that ongoing fluctuations can be shaped by sensorial events to improve the allocation of attention in time. PMID:26986506

  14. 20 kHz ultrasound assisted treatment of chronic wounds with concurrent optic monitoring

    NASA Astrophysics Data System (ADS)

    Bawiec, Christopher R.; Sunny, Youhan; Diaz, David; Nadkarni, Sumati; Weingarten, Michael S.; Neidrauer, Michael; Margolis, David J.; Zubkov, Leonid; Lewin, Peter A.

    2015-05-01

    This paper describes a novel, wearable, battery powered ultrasound applicator that was evaluated as a therapeutic tool for healing of chronic wounds, such as venous ulcers. The low frequency and low intensity (~100mW/cm2) applicator works by generating ultrasound waves with peak-to-peak pressure amplitudes of 55 kPa at 20 kHz. The device was used in a pilot human study (n=25) concurrently with remote optical (diffuse correlation spectroscopy - DCS) monitoring to assess the healing outcome. More specifically, the ulcers' healing status was determined by measuring tissue oxygenation and blood flow in the capillary network. This procedure facilitated an early prognosis of the treatment outcome and - once verified - may eventually enable customization of wound management. The outcome of the study shows that the healing patients of the ultrasound treated group had a statistically improved (p<0.05) average rate of wound healing (20.6%/week) compared to the control group (5.3%/week). In addition, the calculated blood flow index (BFI) decreased more rapidly in wounds that decreased in size, indicating a correlation between BFI and wound healing prediction. Overall, the results presented support the notion that active low frequency ultrasound treatment of chronic venous ulcers accelerates healing when combined with the current standard clinical care. The ultrasound applicator described here provides a user-friendly, fully wearable system that has the potential for becoming the first device suitable for treatment of chronic wounds in patient's homes, which - in turn - would increase patients' compliance and improve quality of life.

  15. Relationship between field strength and arousal response in mice exposed to 60-Hz electric fields

    SciTech Connect

    Rosenberg, R.S.; Duffy, P.H.; Sacher, G.A.; Ehret, C.F.

    1983-01-01

    White-footed mice, Peromyscus leucopus, were exposed to 60-Hz electric fields to study the relationship between field strength and three measures of the transient arousal response previously reported to occur with exposures at 100 kV/m. Five groups of 12 mice each were given a series of four 1-h exposures, separated by an hour, with each group exposed at one of the following field strengths: 75, 50, 35, 25, and 10 kV/m; 8 additional mice were sham-exposed with no voltage applied to the field generator. All mice were experimentally naive before the start of the experiment, and all exposures occurred during the inactive (lights-on) phase of the circadian cycle. The first exposure produced immediate increases in arousal measures, but subsequent exposures had no significant effect on any measure. These arousal responses were defined by significant increases of gross motor activity, carbon dioxide production, and oxygen consumption, and were frequently recorded with field strengths of 50 kV/m or higher. Significant arousal responses rarely occurred with exposures at lower field strengths. Responses of mice exposed at 75 and 50 kV/m were similar to previously described transient arousal responses in mice exposed to 100-kV/m electric fields. Less than half of the mice in each of the field strength groups below 50 kV/m showed arousal response based on Z (standard) scores, but the arousals of the mice that did respond were similar to those of mice exposed at higher field strengths. Polynomial regression was used to calculate the field strength producing the greatest increases for each of the arousal measures. The results show that the amplitude of the transient arousal response is related to the strength of the electric field, but different measures of arousal may have different relationships to field strength.

  16. DNA Strand Breaks in Fibroblasts Exposed to a 50-Hz Magnetic Field

    NASA Astrophysics Data System (ADS)

    Nakayama, Maresuke; Hondou, Tsuyoshi; Miyata, Hidetake

    A large number of studies have reported DNA damages caused by low frequency magnetic field (LFMF). However, the mechanism of the DNA damage is not well understood, partly because of a lack of reproducibility. Because DNA integrity is essential for the activities of life, the present study focused on DNA damages induced by LFMF. Fibroblast cells (3T3 Swiss albino) were exposed for various periods (15, 18 and 24 h) to 50-Hz magnetic fields (MF) of various intensities (100, 500 and 1000 µT). Two modes of exposure, intermittent (on for 5 min, off for 10 min) and continuous, were employed. DNA damages were evaluated by the alkaline comet assay. This assay semi-quantify the degree of DNA strand breaks. With the intermittent 500 µT MF, the degree of DNA strand breaks was higher in the exposed cells than non-exposed cells, and the difference was maximal at 18 h (statistically significant difference was observed at 18 and 24 h). Also with the intermittexnt, 100 and 1000 µT MFs, the degree of DNA strand breaks of exposed cells was higher than non-exposed cells, but the statistically significant difference was observed only at 1000 µT, 18 h exposure. The continuous exposure for 15, 18 and 24 h at 500 µT exhibited a significant difference between the exposed and non-exposed cells only at 18 h, but the difference was not as prominent as that observed under the intermittent exposure.

  17. Ultra-low-noise EEG/MEG systems enable bimodal non-invasive detection of spike-like human somatosensory evoked responses at 1 kHz.

    PubMed

    Fedele, T; Scheer, H J; Burghoff, M; Curio, G; Körber, R

    2015-02-01

    Non-invasive EEG detection of very high frequency somatosensory evoked potentials featuring frequencies up to and above 1 kHz has been recently reported. Here, we establish the detectability of such components by combined low-noise EEG/MEG. We recorded SEP/SEF simultaneously using median nerve stimulation in five healthy human subjects inside an electromagnetically shielded room, combining a low-noise EEG custom-made amplifier (4.7 nV/√Hz) and a custom-made single-channel low-noise MEG (0.5 fT/√Hz @ 1 kHz). Both, low-noise EEG and MEG revealed three spectrally distinct and temporally overlapping evoked components: N20 (<100 Hz), sigma-burst (450-750 Hz), and kappa-burst (850-1200 Hz). The two recording modalities showed similar relative scaling of signal amplitude in all three frequencies domains (EEG [10 nV] ≅ MEG [1 fT]). Pronounced waveform (peak-by-peak) overlap of EEG and MEG signals is observed in the sigma band, whereas in the kappa band overlap was only partial. A decreasing signal-to-noise ratio (SNR; calculated for n = 12.000 averages) from sigma to kappa components characterizes both, electric and magnetic field recordings: Sigma-band SNR was 12.9  ±  5.5/19.8  ±  12.6 for EEG/MEG, and kappa-band SNR at 3.77  ±  0.8/4.5  ±  2.9. High-frequency performance of a tailor-made MEG matches closely with simultaneously recorded low-noise EEG for the non-invasive detection of somatosensory evoked activity at and above 1 kHz. Thus, future multi-channel dual-mode low-noise technology could offer complementary views for source reconstruction of the neural generators underlying such high-frequency responses, and render neural high-frequency processes related to multi-unit spike discharges accessible in non-invasive recordings.

  18. 15 CFR 8.12 - Hearings.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... OF THE DEPARTMENT OF COMMERCE-EFFECTUATION OF TITLE VI OF THE CIVIL RIGHTS ACT OF 1964 General... right to a hearing under section 602 of the Act and § 8.11(c) and consent to the making of a decision on... Administrative Procedures Act), and in accordance with such rules of procedure as......

  19. Media Resources: Secondary Art (8-12).

    ERIC Educational Resources Information Center

    British Columbia Dept. of Education, Victoria. Curriculum Development Branch.

    This resource guide is intended to provide information on films, videotapes, filmstrips, audio-cassettes, and other related materials that can be used as teaching aids to support and enhance the high school art curriculum. The guide provides titles, the format(s) in which material is presented, the source of the material, and a short description…

  20. 15 CFR 8.12 - Hearings.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... administrative review thereof shall be conducted in conformity with 5 U.S.C. 554-557 (sections 5-8 of the... opportunity shall be given to refute facts and arguments advanced on either side of the issues. A...

  1. 24 CFR 8.12 - Employment criteria.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... handicap that impairs sensory, manual, or speaking skills, the test results accurately reflect the..., rather than the applicant's or employee's impaired sensory, manual, or speaking skills (except...

  2. Plasma antennas driven by 5–20 kHz AC power supply

    SciTech Connect

    Zhao, Jiansen Chen, Yuli; Sun, Yang; Wu, Huafeng; Liu, Yue; Yuan, Qiumeng

    2015-12-15

    The experiments described in this work were performed with the aim of introducing a new plasma antenna that was excited by a 5–20 kHz alternating current (AC) power supply, where the antenna was transformed into a U-shape. The results show that the impedance, voltage standing-wave ratio (VSWR), radiation pattern and gain characteristics of the antenna can be controlled rapidly by varying not only the discharge power, but also by varying the discharge frequency in the range from 5 to 20 kHz. When the discharge frequency is adjusted from 10 to 12 kHz, the gain is higher within a relatively broad frequency band and the switch-on time is less than 1 ms when the discharge power is less than 5 W, meaning that the plasma antenna can be turned on and off rapidly.

  3. Afferent inputs to cortical fast-spiking interneurons organize pyramidal cell network oscillations at high-gamma frequencies (60-200 Hz).

    PubMed

    Suffczynski, Piotr; Crone, Nathan E; Franaszczuk, Piotr J

    2014-12-01

    High-gamma activity, ranging in frequency between ∼60 Hz and 200 Hz, has been observed in local field potential, electrocorticography, EEG and magnetoencephalography signals during cortical activation, in a variety of functional brain systems. The origin of these signals is yet unknown. Using computational modeling, we show that a cortical network model receiving thalamic input generates high-gamma responses comparable to those observed in local field potential recorded in monkey somatosensory cortex during vibrotactile stimulation. These high-gamma oscillations appear to be mediated mostly by an excited population of inhibitory fast-spiking interneurons firing at high-gamma frequencies and pacing excitatory regular-spiking pyramidal cells, which fire at lower rates but in phase with the population rhythm. The physiological correlates of high-gamma activity, in this model of local cortical circuits, appear to be similar to those proposed for hippocampal ripples generated by subsets of interneurons that regulate the discharge of principal cells. PMID:25210164

  4. EEG oscillatory activity associated to monetary gain and loss signals in a learning task: effects of attentional impulsivity and learning ability.

    PubMed

    De Pascalis, Vilfredo; Varriale, Vincenzo; Rotonda, Marco

    2012-07-01

    This study investigated the influence of individual differences in attentional impulsivity (Att-Imp), learning ability, and learning practice on oscillatory activity and phase synchrony responses to monetary gain and loss signals during an instrumental-learning task in healthy women. We used a trial-by-trial wavelet-based time-frequency analysis of the electroencephalographic (EEG) signal to provide amplitude and inter-site phase synchrony measures from 30 electrodes in theta (4-8 Hz, 350-500 ms), alpha (8-12 Hz, 100-200 ms), beta (13-25 Hz, 100-200 ms), and gamma (30-40 Hz, 350-450 ms) time-frequency ranges. Oscillatory amplitude and inter-site phase synchrony were both greater following loss signals as compared to gain signals in theta, beta, and gamma frequency bands. Low Att-Imp subjects had higher theta activity within a 350-500 ms time window over frontocentral, and centroparietal sites than high Att-Imp subjects. Monetary gain signals elicited higher theta and gamma activities in high Att-Imp individuals and loss signals elicited higher activities to loss signals in low Att-Imp individuals. Good learners showed enhanced intrahemispheric theta synchrony between frontoparietal, and fronto-occipital sites to monetary loss compared to gain signals. In good learners, monetary loss produced an increase of gamma synchrony that enhanced in the second stage of learning. In low Att-Imp individuals, there was a reduction of theta synchrony during the second stage, as compared with the first stage of learning, between temporal, parietal and fronto-parietal brain regions. These findings may offer valuable clues to understand outcome processing, attentional impulsivity, and learning ability. We propose that the punishment-related theta and gamma waves play a leading role in learning process.

  5. The MR detection of neuronal depolarization during 3-Hz spike-and-wave complexes in generalized epilepsy.

    PubMed

    Liston, Adam D; Salek-Haddadi, Afraim; Kiebel, Stefan J; Hamandi, Khalid; Turner, Robert; Lemieux, Louis

    2004-12-01

    Previously, an analysis of activations observed in a patient with idiopathic generalized epilepsy using electroencephalogram-correlated functional magnetic resonance imaging (MRI) during runs of 3-Hz generalized spike-wave discharge (GSWD) was presented by Salek-Haddadi. Time-locked, bilateral, thalamic blood oxygenation level-dependent increases were reported to be accompanied by widespread, symmetric, cortical deactivation with a frontal maximum. In light of recent investigations into MRI detection of the magnetic field perturbations caused by neuronal current loops during depolarization, we revisited the analysis of the data of Salek-Haddadi as a preliminary search for a neuroelectric signal. We modeled the MRI response as the sum of a fast signal and a slower signal and demonstrated significant MRI activity at a time scale of the order of 30 ms associated with GSWDs. Further work is necessary before firm conclusions may be drawn about the nature of this signal.

  6. Calibration of laser vibrometers at frequencies up to 100 kHz and higher

    NASA Astrophysics Data System (ADS)

    Silva Pineda, Guillermo; von Martens, Hans-Jürgen; Rojas, Sergio; Ruiz, Arturo; Muñiz, Lorenzo

    2008-06-01

    Manufacturers and users of laser vibrometers exploit the wide frequency and intensity ranges of laser techniques, ranging over many decades (e.g., from 0.1 Hz to 100 MHz). Traceability to primary measurement standards is demanded over the specified measurement ranges of any measurement instrumentation. As the primary documentary standard ISO 16063-11 for the calibration of vibration transducers is restricted to 10 kHz, a new international standard for the calibration of laser vibrometers, ISO 16063-41, is under development. The current stage of the 2nd Committee Draft (CD) of the ISO standard specifies calibration methods for frequencies from 0.4 Hz to 50 kHz which does not meet the demand for providing traceability at higher frequencies. New investigations will be presented which demonstrate the applicability of the laser interferometer methods specified in ISO 16063-11 and in the 2nd CD also at higher frequencies of 100 kHz and beyond. The three standard methods were simultaneously used for vibration displacement and acceleration measurements up to 100 kHz, and a fourth high-accuracy method has been developed and used. Their results in displacement and acceleration measurements deviated by less than 1 % from each other at vibration displacement amplitudes in the order of 100 nm. In addition to the three interferometer methods specified in ISO 16063-11 and 16063-15, and in the 2nd Committee Draft of 16063-41 as well, measurement results will be presented. Examples of laser vibrometer calibrations will bedemonstrated. Further investigations are aimed

  7. Spectrally encoded confocal microscopy of esophageal tissues at 100 kHz line rate

    PubMed Central

    Schlachter, Simon C.; Kang, DongKyun; Gora, Michalina J.; Vacas-Jacques, Paulino; Wu, Tao; Carruth, Robert W.; Wilsterman, Eric J.; Bouma, Brett E.; Woods, Kevin; Tearney, Guillermo J.

    2013-01-01

    Spectrally encoded confocal microscopy (SECM) is a reflectance confocal microscopy technology that uses a diffraction grating to illuminate different locations on the sample with distinct wavelengths. SECM can obtain line images without any beam scanning devices, which opens up the possibility of high-speed imaging with relatively simple probe optics. This feature makes SECM a promising technology for rapid endoscopic imaging of internal organs, such as the esophagus, at microscopic resolution. SECM imaging of the esophagus has been previously demonstrated at relatively low line rates (5 kHz). In this paper, we demonstrate SECM imaging of large regions of esophageal tissues at a high line imaging rate of 100 kHz. The SECM system comprises a wavelength-swept source with a fast sweep rate (100 kHz), high output power (80 mW), and a detector unit with a large bandwidth (100 MHz). The sensitivity of the 100-kHz SECM system was measured to be 60 dB and the transverse resolution was 1.6 µm. Excised swine and human esophageal tissues were imaged with the 100-kHz SECM system at a rate of 6.6 mm2/sec. Architectural and cellular features of esophageal tissues could be clearly visualized in the SECM images, including papillae, glands, and nuclei. These results demonstrate that large-area SECM imaging of esophageal tissues can be successfully conducted at a high line imaging rate of 100 kHz, which will enable whole-organ SECM imaging in vivo. PMID:24049684

  8. Comparison of cardiac and 60 Hz magnetically induced electric fields measured in anesthetized rats

    SciTech Connect

    Miller, D.L.; Creim, J.A.

    1997-06-01

    Extremely low frequency magnetic fields interact with an animal by inducing internal electric fields, which are in addition to the normal endogenous fields present in living animals. Male rats weighing about 560 g each were anesthetized with ketamine and xylazine. Small incisions were made in the ventral body wall at the chest and upper abdomen to position a miniature probe for measuring internal electric fields. The calibration constant for the probe size was 5.7 mm, with a flat response from at least 12 Hz to 20 kHz. A cardiac signal, similar to the normal electrocardiogram with a heart rate of about 250 bpm, was readily obtained at the chest. Upon analysis of its spectrum, the cardiac field detected by the probe had a broad maximum at 32--95 Hz. When the rates were exposed to a 1 mT, 60 Hz magnetic field, a spike appeared in the spectrum at 60 Hz. The peak-to-peak magnitudes of electric fields associated with normal heart function were comparable to fields induced by a 1 mT magnetic field at 60 Hz for those positions measured on the body surface. Within the body, or in different directions relative to the applied field, the induced fields were reduced. The cardiac field increased near the heart, becoming much larger than the induced field. Thus, the cardiac electric field, together with the other endogenous fields, combine with induced electric fields and help to provide reference levels for the induced-field dosimetry of ELF magnetic field exposures of living animals.

  9. SOFT LAGS IN NEUTRON STAR kHz QUASI-PERIODIC OSCILLATIONS: EVIDENCE FOR REVERBERATION?

    SciTech Connect

    Barret, Didier

    2013-06-10

    High frequency soft reverberation lags have now been detected from stellar mass and supermassive black holes. Their interpretation involves reflection of a hard source of photons onto an accretion disk, producing a delayed reflected emission, with a time lag consistent with the light travel time between the irradiating source and the disk. Independently of the location of the clock, the kHz quasi-periodic oscillation (QPO) emission is thought to arise from the neutron star boundary layer. Here, we search for the signature of reverberation of the kHz QPO emission, by measuring the soft lags and the lag energy spectrum of the lower kHz QPOs from 4U1608-522. Soft lags, ranging from {approx}15 to {approx}40 {mu}s, between the 3-8 keV and 8-30 keV modulated emissions are detected between 565 and 890 Hz. The soft lags are not constant with frequency and show a smooth decrease between 680 Hz and 890 Hz. The broad band X-ray spectrum is modeled as the sum of a disk and a thermal Comptonized component, plus a broad iron line, expected from reflection. The spectral parameters follow a smooth relationship with the QPO frequency, in particular the fitted inner disk radius decreases steadily with frequency. Both the bump around the iron line in the lag energy spectrum and the consistency between the lag changes and the inferred changes of the inner disk radius, from either spectral fitting or the QPO frequency, suggest that the soft lags may indeed involve reverberation of the hard pulsating QPO source on the disk.

  10. Dynamical mass determinations for the white dwarf components of HZ 9 and Case 1

    NASA Technical Reports Server (NTRS)

    Stauffer, John R.

    1987-01-01

    Radial-velocity curves for both components of the short-period, white dwarf M dwarf binary systems Case 1 and HZ 9 have been determined from 1-A-resolution spectra obtained at the MMT. The radial-velocity curves for the M dwarf components agree well with previous determinations. The new data have been used to estimate masses for the white dwarfs, yielding 0.38 solar mass for the Case 1 DA and 0.51 solar mass for the HZ 9 DA, with 1sigma uncertainties of about 0.1 solar mass.

  11. 1 Hz FLARING IN SAX J1808.4-3658: FLOW INSTABILITIES NEAR THE PROPELLER STAGE

    SciTech Connect

    Patruno, Alessandro; Watts, Anna; Klein Wolt, Marc; Wijnands, Rudy; Van der Klis, Michiel

    2009-12-20

    We present a simultaneous periodic and aperiodic timing study of the accreting millisecond X-ray pulsar SAX J1808.4-3658. We analyze five outbursts of the source and for the first time provide a full and systematic investigation of the enigmatic phenomenon of the 1 Hz flares observed during the final stages of some of the outbursts. We show that links between pulsations and 1 Hz flares might exist, and suggest that they are related with hydrodynamic disk instabilities that are triggered close to the disk-magnetosphere boundary layer when the system is entering the propeller regime.

  12. Near real-time response matrix calibration for 10 Hz GOFB

    SciTech Connect

    Liu C.; Hulsart, R.; Marusic, A.; Mernick, K.; Michnoff, R.; Minty, M.

    2012-05-20

    The 10 Hz global orbit feedback (GOFB), for damping the trajectory perturbation ({approx}10 Hz) due to the vibrations of the triplet quadrupoles, is operational. The correction algorithm uses transfer functions between the beam position monitors and correctors obtained from the online optics model and a correction algorithm based on singular value decomposition (SVD). Recently the calibration of the transfer functions was measured using beam position measurements acquired while modulating dedicated correctors. In this report, the feedback results with model matrix and measured matrix are compared.

  13. A kHz heat-load shutter for white-beam experiments at synchrotron sources.

    PubMed

    Gembicky, Milan; Adachi, Shin Ichi; Coppens, Philip

    2007-05-01

    A heat-load shutter capable of frequencies from one to several tens of kHz and window times from 10 micros up to 1 ms is described. In the current configuration the water-cooled shutter absorbs approximately 99% of the heat generated by the white beam. It has been successfully used for extended periods synchronized with a Jülich pulse-selector operating at 946 Hz. The temperature of the pulse-selector remained constant during a three-day continuous operation. Flexibility is provided by the interchangeability of the chopper disc.

  14. Sperm whales reduce foraging effort during exposure to 1-2 kHz sonar and killer whale sounds.

    PubMed

    Isojunno, Saana; Cure, Charlotte; Kvadsheim, Petter Helgevold; Lam, Frans-Peter Alexander; Tyack, Peter Lloyd; Wensveen, Paul Jacobus; Miller, Patrick James O'Malley

    2016-01-01

    The time and energetic costs of behavioral responses to incidental and experimental sonar exposures, as well as control stimuli, were quantified using hidden state analysis of time series of acoustic and movement data recorded by tags (DTAG) attached to 12 sperm whales (Physeter macrocephalus) using suction cups. Behavioral state transition modeling showed that tagged whales switched to a non-foraging, non-resting state during both experimental transmissions of low-frequency active sonar from an approaching vessel (LFAS; 1-2 kHz, source level 214 dB re 1 µPa m, four tag records) and playbacks of potential predator (killer whale, Orcinus orca) sounds broadcast at naturally occurring sound levels as a positive control from a drifting boat (five tag records). Time spent in foraging states and the probability of prey capture attempts were reduced during these two types of exposures with little change in overall locomotion activity, suggesting an effect on energy intake with no immediate compensation. Whales switched to the active non-foraging state over received sound pressure levels of 131-165 dB re 1 µPa during LFAS exposure. In contrast, no changes in foraging behavior were detected in response to experimental negative controls (no-sonar ship approach or noise control playback) or to experimental medium-frequency active sonar exposures (MFAS; 6-7 kHz, source level 199 re 1 µPa m, received sound pressure level [SPL] = 73-158 dB re 1 µPa). Similarly, there was no reduction in foraging effort for three whales exposed to incidental, unidentified 4.7-5.1 kHz sonar signals received at lower levels (SPL = 89-133 dB re 1 µPa). These results demonstrate that similar to predation risk, exposure to sonar can affect functional behaviors, and indicate that increased perception of risk with higher source level or lower frequency may modulate how sperm whales respond to anthropogenic sound. PMID:27039511

  15. Sperm whales reduce foraging effort during exposure to 1-2 kHz sonar and killer whale sounds.

    PubMed

    Isojunno, Saana; Cure, Charlotte; Kvadsheim, Petter Helgevold; Lam, Frans-Peter Alexander; Tyack, Peter Lloyd; Wensveen, Paul Jacobus; Miller, Patrick James O'Malley

    2016-01-01

    The time and energetic costs of behavioral responses to incidental and experimental sonar exposures, as well as control stimuli, were quantified using hidden state analysis of time series of acoustic and movement data recorded by tags (DTAG) attached to 12 sperm whales (Physeter macrocephalus) using suction cups. Behavioral state transition modeling showed that tagged whales switched to a non-foraging, non-resting state during both experimental transmissions of low-frequency active sonar from an approaching vessel (LFAS; 1-2 kHz, source level 214 dB re 1 µPa m, four tag records) and playbacks of potential predator (killer whale, Orcinus orca) sounds broadcast at naturally occurring sound levels as a positive control from a drifting boat (five tag records). Time spent in foraging states and the probability of prey capture attempts were reduced during these two types of exposures with little change in overall locomotion activity, suggesting an effect on energy intake with no immediate compensation. Whales switched to the active non-foraging state over received sound pressure levels of 131-165 dB re 1 µPa during LFAS exposure. In contrast, no changes in foraging behavior were detected in response to experimental negative controls (no-sonar ship approach or noise control playback) or to experimental medium-frequency active sonar exposures (MFAS; 6-7 kHz, source level 199 re 1 µPa m, received sound pressure level [SPL] = 73-158 dB re 1 µPa). Similarly, there was no reduction in foraging effort for three whales exposed to incidental, unidentified 4.7-5.1 kHz sonar signals received at lower levels (SPL = 89-133 dB re 1 µPa). These results demonstrate that similar to predation risk, exposure to sonar can affect functional behaviors, and indicate that increased perception of risk with higher source level or lower frequency may modulate how sperm whales respond to anthropogenic sound.

  16. Intensity-difference limens for very brief Gaussian-shaped tones at 500 Hz and 6.5 kHz

    NASA Astrophysics Data System (ADS)

    Nizami, Lance; Jesteadt, Walt

    2002-05-01

    The curve of intensity-difference limen (DL) versus level shows a midlevel hump for 6.5-kHz tones having 5-ms cosine-squared ramps and a 26-ms plateau [Carlyon and Moore, J. Acoust. Soc. Am. 76, 1369-1376 (1984)]. DLs were presently obtained for that tone, as well as for 6.5-kHz tones having Gaussian envelopes, for five subjects. Pedestal levels covered 30- to 90-dB SPL and equivalent rectangular durations D were 0.314, 0.627, 1.25, 2.51, 10.03, and 20.1 ms, where D is the Gaussian-envelope duration divided by 3.19. The DLs for the tone of Carlyon and Moore (D~30) show a midlevel hump smaller than found earlier. The hump grows noticeably with smaller D (i.e., the Gaussian-shaped tones), reaching 7 dB for D=0.627. The peak drops, however, for D=0.314, causing the curve of DL versus duration to peak for D=0.627 for tone levels of 40-60 dB SPL. DLs were also obtained from seven subjects for 500-Hz tones of 30-90 dB SPL for D's of 1.25, 2.51, 5.02, and 10.03 ms. A midlevel hump at D's of 1.25 and 2.51 gives way to a near-miss at D's of 5.02 and 10.03. A mid-duration peak is seen at D=5.02 for levels of 30-60 dB SPL.

  17. Mapping and mining interictal pathological gamma (30–100 Hz) oscillations with clinical intracranial EEG in patients with epilepsy

    PubMed Central

    Smart, Otis; Maus, Douglas; Marsh, Eric; Dlugos, Dennis; Litt, Brian; Meador, Kimford

    2012-01-01

    Localizing an epileptic network is essential for guiding neurosurgery and antiepileptic medical devices as well as elucidating mechanisms that may explain seizure-generation and epilepsy. There is increasing evidence that pathological oscillations may be specific to diseased networks in patients with epilepsy and that these oscillations may be a key biomarker for generating and indentifying epileptic networks. We present a semi-automated method that detects, maps, and mines pathological gamma (30–100 Hz) oscillations (PGOs) in human epileptic brain to possibly localize epileptic networks. We apply the method to standard clinical iEEG (<100 Hz) with interictal PGOs and seizures from six patients with medically refractory epilepsy. We demonstrate that electrodes with consistent PGO discharges do not always coincide with clinically determined seizure onset zone (SOZ) electrodes but at times PGO-dense electrodes include secondary seizure-areas (SS) or even areas without seizures (NS). In 4/5 patients with epilepsy surgery, we observe poor (Engel Class 4) post-surgical outcomes and identify more PGO-activity in SS or NS than in SOZ. Additional studies are needed to further clarify the role of PGOs in epileptic brain. PMID:23105174

  18. Changes in the spectral composition of animal-brain electrical activity under the influence of nonthermal millimeter-wave radiation on acupuncture points

    SciTech Connect

    Khramov, R.N.; Vorob`ev, V.V.

    1994-07-01

    The frequency spectra (0-26 Hz) of electrograms (EG) of the preoptic region of the hypothalamus were studied in chronic experiments on nine awake rabbits under the influence of nonthermal millimeter-bank (55-75 GHz) electromagnetic fields on various acupuncture points: (I) the auricular {open_quotes}heart{close_quotes} point (after F. G. Portnov); (II) the cranial acupoint (TR-20; the {open_quotes}hypothalamus{close_quotes} point after R. Voll); and (III) the {open_quotes}longevity{close_quotes} acupoint (E-36). Irradiation of point I was accompanied by significant suppression of hypothalamic electrical activity at 5 and 16 Hz and enhancement at 7-8, 12, and 26 Hz. Irradiation of point II, and III were, respectively, 31%, 21%, and 5% (p < 0.05, U-criterion). These results suggest that acupuncture points I and II are more sensitive to millimeter-band radiation than is point III. The presence of individual characteristics of the effects and their change after stress to sign inversion were shown in rat experiments in which the acupuncture points were irradiated.

  19. Repeated 6-Hz Corneal Stimulation Progressively Increases FosB/ΔFosB Levels in the Lateral Amygdala and Induces Seizure Generalization to the Hippocampus

    PubMed Central

    Giordano, Carmela; Vinet, Jonathan; Curia, Giulia; Biagini, Giuseppe

    2015-01-01

    Exposure to repetitive seizures is known to promote convulsions which depend on specific patterns of network activity. We aimed at evaluating the changes in seizure phenotype and neuronal network activation caused by a modified 6-Hz corneal stimulation model of psychomotor seizures. Mice received up to 4 sessions of 6-Hz corneal stimulation with fixed current amplitude of 32 mA and inter-stimulation interval of 72 h. Video-electroencephalography showed that evoked seizures were characterized by a motor component and a non-motor component. Seizures always appeared in frontal cortex, but only at the fourth stimulation they involved the hippocampus, suggesting the establishment of an epileptogenic process. Duration of seizure non-motor component progressively decreased after the second session, whereas convulsive seizures remained unchanged. In addition, a more severe seizure phenotype, consisting of tonic-clonic generalized convulsions, was predominant after the second session. Immunohistochemistry and double immunofluorescence experiments revealed a significant increase in neuronal activity occurring in the lateral amygdala after the fourth session, most likely due to activity of principal cells. These findings indicate a predominant role of amygdala in promoting progressively more severe convulsions as well as the late recruitment of the hippocampus in the seizure spread. We propose that the repeated 6-Hz corneal stimulation model may be used to investigate some mechanisms of epileptogenesis and to test putative antiepileptogenic drugs. PMID:26555229

  20. Report on key comparison COOMET.AUV.A-K5: pressure calibration of laboratory standard microphones in the frequency range 2 Hz to 10 kHz

    NASA Astrophysics Data System (ADS)

    Dobrowolska, D.; Kosterov, A.

    2016-01-01

    This is the final report for regional key comparison COOMET.AUV.A-K5 on the pressure calibration of laboratory standard microphones in the frequency range from 2 Hz to 10 kHz. Two laboratories—Central Office of Measures (GUM)—the national metrology institute for Poland and the State Enterprise Scientific-Research Institute for Metrology of Measurement and Control Systems (DP NDI Systema)— the designated institute for acoustics in Ukraine took part in this comparison with the GUM as a pilot. One travelling type LS1P microphone was circulated to the participants and results in the form of regular calibration certificates were collected. The results of the DP NDI Systema obtained in this comparison were linked to the CCAUV.A-K5 key comparison through the joint participation of the GUM. The degrees of equivalence were computed for DP NDI Systema with respect to the CCAUV.A-K5 key comparison reference value. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCAUV, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  1. High-sensitivity cooled coil system for nuclear magnetic resonance in kHz range

    SciTech Connect

    Lin, Tingting; Zhao, Jing; Zhang, Yi; Krause, Hans-Joachim; Lee, Yong-Ho; Lin, Jun

    2014-11-15

    In several low-field Nuclear Magnetic Resonance (LF-NMR) and surface nuclear magnetic resonance applications, i.e., in the frequency range of kHz, high sensitivity magnetic field detectors are needed. Usually, low-T{sub c} superconducting quantum interference devices (SQUIDs) with a high field sensitivity of about 1 fT/Hz{sup 1/2} are employed as detectors. Considering the flux trapping and operational difficulties associated with low-T{sub c} SQUIDs, we designed and fabricated liquid-nitrogen-cooled Cu coils for NMR detection in the kHz range. A cooled coil system consisting of a 9-cm diameter Cu coil and a low noise preamplifier was systematically investigated and reached a sensitivity of 2 fT/Hz{sup 1/2} at 77 K, which is 3 times better compared to the sensitivity at 300 K. A Q-switch circuit as an essential element for damping the ringing effects of the pickup coil was developed to acquire free induction decay signals of a water sample with minimum loss of signal. Our studies demonstrate that cooled Cu coils, if designed properly, can provide a comparable sensitivity to low-T{sub c} SQUIDs.

  2. Monitoring audiometry for occupational hearing loss: A case for eliminating 500 Hz

    NASA Astrophysics Data System (ADS)

    Stephenson, Mark

    2003-04-01

    Audiometric monitoring is an important element in hearing conservation programs. Nearly every existing hearing conservation standard dictate that hearing thresholds should be measured at specific frequencies, and that 500 Hz be among those frequencies tested. Actual and estimated noise-induced permanent threshold shifts were evaluated as a function of exposure duration and exposure level. The results demonstrate 500 Hz to be of little value in assessing noise-induced hearing loss for typical industrial noise exposures of up to 40 years, at least for time-weighted average exposures of up to 100 dBA. Furthermore, few hearing conservation programs currently require audiometric monitoring to be performed in an environment that meets ANSI standards for maximum permissible background noise levels. This is particularly likely to compromise hearing testing at 500 Hz. As a result, this paper argues against the need for testing at 500 Hz, and recommends it be eliminated as a required test frequency in audiometric monitoring for noise-induced occupational hearing loss.

  3. Improvement of both dystonia and tics with 60 Hz pallidal deep brain stimulation.

    PubMed

    Hwynn, Nelson; Tagliati, Michele; Alterman, Ron L; Limotai, Natlada; Zeilman, Pamela; Malaty, Irene A; Foote, Kelly D; Morishita, Takashi; Okun, Michael S

    2012-09-01

    Deep brain stimulation has been utilized in both dystonia and in medication refractory Tourette syndrome. We present an interesting case of a patient with a mixture of disabling dystonia and Tourette syndrome whose coexistent dystonia and tics were successfully treated with 60 Hz-stimulation of the globus pallidus region.

  4. Twelve years of tracking 52-Hz whale calls from a unique source in the North Pacific

    NASA Astrophysics Data System (ADS)

    Watkins, William A.; Daher, Mary Ann; George, Joseph E.; Rodriguez, David

    2004-12-01

    A unique whale call with 50-52 Hz emphasis from a single source has been tracked over 12 years in the central and eastern North Pacific. These calls, referred to as 52-Hz calls, were monitored and analyzed from acoustic data recorded by hydrophones of the US Navy Sound Surveillance System (SOSUS) and other arrays. The calls were noticed first in 1989, and have been detected and tracked since 1992. No other calls with similar characteristics have been identified in the acoustic data from any hydrophone system in the North Pacific basin. Only one series of these 52-Hz calls has been recorded at a time, with no call overlap, suggesting that a single whale produced the calls. The calls were recorded from August to February with most in December and January. The species producing these calls is unknown. The tracks of the 52-Hz whale were different each year, and varied in length from 708 to 11,062 km with travel speeds ranging from 0.7 to 3.8 km/h. Tracks included (A) meandering over short ranges, (B) predominantly west-to-east movement, and (C) mostly north-to-south travel. These tracks consistently appeared to be unrelated to the presence or movement of other whale species (blue, fin and humpback) monitored year-round with the same hydrophones.

  5. Dynamic nuclear polarization at 40 kHz magic angle spinning.

    PubMed

    Chaudhari, Sachin R; Berruyer, Pierrick; Gajan, David; Reiter, Christian; Engelke, Frank; Silverio, Daniel L; Copéret, Christophe; Lelli, Moreno; Lesage, Anne; Emsley, Lyndon

    2016-04-21

    DNP-enhanced solid-state NMR spectroscopy under magic angle spinning (MAS) is rapidly developing into a powerful analytical tool to investigate the structure of a wide range of solid materials, because it provides unsurpassed sensitivity gains. Most developments and applications of DNP MAS NMR were so far reported at moderate spinning frequencies (up to 14 kHz using 3.2 mm rotors). Here, using a 1.3 mm MAS DNP probe operating at 18.8 T and ∼100 K, we show that signal amplification factors can be increased by up to a factor two when using smaller volume rotors as compared to 3.2 mm rotors, and report enhancements of around 60 over a range of sample spinning rates from 10 to 40 kHz. Spinning at 40 kHz is also shown to increase (29)Si coherence lifetimes by a factor three as compared to 10 kHz, substantially increasing sensitivity in CPMG type experiments. The contribution of quenching effects to the overall sensitivity gain at very fast MAS is evaluated, and applications are reported on a functionalised mesostructured organic-inorganic material.

  6. An 18 bit 50 kHz ADC for low earth orbit

    NASA Technical Reports Server (NTRS)

    Thelen, Donald C.

    1992-01-01

    A fourth order incremental analog to digital converter (ADC) is proposed which performs 18 bit conversions at a 50 kHz rate on sampled and held data. A new self calibration scheme is presented which eases the matching requirements of capacitors, and the performance of the operational amplifiers in the ADC by changing coefficients in the digital postprocessing.

  7. H/Z-90 Personal Computer Workstation for the Prime 550.

    ERIC Educational Resources Information Center

    Saturday, Lisa L.; Green, David G.

    1985-01-01

    A Heath/Zenith H/Z-90 personal workstation for a PRIME 550 host computer has been developed. The personal computer-based workstation has local editing capability with automatic upload and download of PRIME files, supports a local printer, and provides backup of files on local floppy disk. (Author)

  8. Accommodative response and cortical activity during sustained attention.

    PubMed

    Poltavski, Dmitri V; Biberdorf, David; Petros, Thomas V

    2012-06-15

    Greater accommodative lag and vergence deficits have been linked to attentional deficits similar to those observed in Attention Deficit Hyperactivity Disorder (ADHD). The purpose of the present study was to assess the effect of accommodative-vergence stress on a measure of sustained attention (Conners CPT) used in the diagnosis of ADHD. Twenty-seven normal non-ADHD adults completed the Conners CPT twice: wearing -2.00 D lenses and normally (without the -2.00 D lenses) in a counterbalanced order with at least 24 h between the sessions. Simultaneous recording of participants' dynamic accommodative responses was performed from the right eye using the Grand Seiko WAM-5500 auto-refractor and electroencephalographic activity (EEG) in the left prefrontal region using the Neurosky Mindset headset. The results demonstrated a significantly greater accommodative lag in the -2.00 D stress condition and a significantly poorer performance on the Conners CPT as indexed by slower reaction time, greater standard error of hit reaction time, grater response variability, poorer stimulus detectability and a greater number of perseverations. No differences were observed on measures of EEG in the theta (4-7 Hz), alpha (8-12 Hz), and beta (12-20 Hz) bands. Moreover, when directly juxtaposed with each EEG band in multiple linear regression analyses, greater accommodative lag in the stress condition was significantly associated with a greater probability of clinical classification on the Conners CPT, and was also marginally predictive of the number of omissions recorded in the stress condition. The results demonstrated that sustained attention can be influenced by such factors as accommodative-vergence stress and suggest that bottom-up processes can contribute to and potentially exacerbate attentional problems in individuals with ADHD. The study also showed that cortical dysfunction (while sufficient) may not be a necessary condition for attentional deficits.

  9. HZ Her: Stellar radius from X-ray eclipse observations, evolutionary state, and a new distance

    SciTech Connect

    Leahy, D. A.; Abdallah, M. H.

    2014-10-01

    Observations of HZ Her/Her X-1 by the Rossi X-Ray Timing Explorer (RXTE) covering high state eclipses of the neutron star are analyzed here. Models of the eclipse are used to measure the radius and atmospheric scale height of HZ Her, the stellar companion to the neutron star. The radius is 2.58-3.01 × 10{sup 11} cm, depending on system inclination and mass ratio (q), with an accuracy of ∼1 part in 1000 for given inclination and q. We fit Kurucz model stellar atmosphere models to archival optical observations. The resulting effective temperature (T {sub eff}) of the unheated face of HZ Her is determined to be in the 2σ range of 7720 K-7865 K, and metallicity (log (Z/Z {sub ☉})) in the range of –0.27 to +.03. The model atmosphere surface flux and new radius yield a new distance to HZ Her/Her X-1, depending on system inclination and q: a best-fit value of 6.1 kpc with upper and lower limits of 5.7 kpc and 7.0 kpc. We calculate stellar evolution models for the range of allowed masses (from orbital parameters) and allowed metallicities (from optical spectrum fits). The stellar models agree with T {sub eff} and the radius of HZ Her for two narrow ranges of mass: 2.15-2.20 M {sub ☉} and 2.35-2.45 M {sub ☉}. This lower mass range implies a low neutron star mass (1.3 M {sub ☉}), whereas the higher mass range implies a high neutron star mass (1.5-1.7 M {sub ☉}).

  10. Coherent WDM, toward > 1 bit/s/Hz information spectral density

    NASA Astrophysics Data System (ADS)

    Ellis, Andrew D.; Gunning, Fatima C.

    2005-06-01

    Many approaches to achieving high information spectral density (ISD), have been reported recently. The standard non-return-to-zero (NRZ) format, which offers a base line performance around 0.4 bit/s/Hz, may be enhanced using a variety of techniques, including: pre-filtering within the transmitter, multi-level modulation formats and polarisation interleaving or multiplexing. These techniques either increase the information per channel (multi-level formats and polarization multiplexing) or minimise interferometric cross talk (pre-filtering and polarisation interleaving) and result in ISDs around 0.8 bit/s/Hz. Combinations of these techniques have been used to provide ISDs of up to 1.6 bit/s/Hz. In this paper we propose a new technique, which we call Coherent WDM (CoWDM), to increase the ISD of NRZ binary coded signals in a single polarisation from 0.4 to 1 bit/s/Hz whilst simultaneously eliminating the need for pre-filters within the transmitter. Phase control within the transmitter is used to achieve precise control of interferometric cross talk. This allows the use of stronger demultiplexing filters at the receiver, and provides optimum performance when the bit rate equals the channel spacing, giving an ISD of 1 bit/s/Hz. This interference control may be achieved by controlling the phase of each laser individually with optical phase locked loops, or by replacing the typical bank of lasers with one or more coherent comb sources, and encoding data using an array of modulators that preserves this relative optical phase. Since optical filtering is not required in the transmitter, stronger optical filters may be used to demultiplex the individual WDM channels at the receiver, further reducing cross talk.

  11. A novel self-guided approach to alpha activity training.

    PubMed

    van Boxtel, Geert J M; Denissen, Ad J M; Jäger, Mark; Vernon, David; Dekker, Marian K J; Mihajlović, Vojkan; Sitskoorn, Margriet M

    2012-03-01

    Fifty healthy participants took part in a double-blind placebo-controlled study in which they were either given auditory alpha activity (8-12Hz) training (N=18), random beta training (N=12), or no training at all (N=20). A novel wireless electrode system was used for training without instructions, involving water-based electrodes mounted in an audio headset. Training was applied approximately at central electrodes. Post-training measurement using a conventional full-cap EEG system revealed a 10% increase in alpha activity at posterior sites compared to pre-training levels, when using the conventional index of alpha activity and a non-linear regression fit intended to model individual alpha frequency. This statistically significant increase was present only in the group that received the alpha training, and remained evident at a 3 month follow-up session, especially under eyes open conditions where an additional 10% increase was found. In an exit interview, approximately twice as many participants in the alpha training group (53%) mentioned that the training was relaxing, compared to those in either the beta (20%) or no training (21%) control groups. Behavioural measures of stress and relaxation were indicative of effects of alpha activity training but failed to reach statistical significance. These results are discussed in terms of a lack of statistical power. Overall, results suggest that self-guided alpha activity training using this novel system is feasible and represents a step forward in the ease of instrumental conditioning of brain rhythms.

  12. Oscillatory phase modulates the timing of neuronal activations and resulting behavior.

    PubMed

    Coon, W G; Gunduz, A; Brunner, P; Ritaccio, A L; Pesaran, B; Schalk, G

    2016-06-01

    Human behavioral response timing is highly variable from trial to trial. While it is generally understood that behavioral variability must be due to trial-by-trial variations in brain function, it is still largely unknown which physiological mechanisms govern the timing of neural activity as it travels through networks of neuronal populations, and how variations in the timing of neural activity relate to variations in the timing of behavior. In our study, we submitted recordings from the cortical surface to novel analytic techniques to chart the trajectory of neuronal population activity across the human cortex in single trials, and found joint modulation of the timing of this activity and of consequent behavior by neuronal oscillations in the alpha band (8-12Hz). Specifically, we established that the onset of population activity tends to occur during the trough of oscillatory activity, and that deviations from this preferred relationship are related to changes in the timing of population activity and the speed of the resulting behavioral response. These results indicate that neuronal activity incurs variable delays as it propagates across neuronal populations, and that the duration of each delay is a function of the instantaneous phase of oscillatory activity. We conclude that the results presented in this paper are supportive of a general model for variability in the effective speed of information transmission in the human brain and for variability in the timing of human behavior. PMID:26975551

  13. Generation of 6.05J nanosecond pulses at a 1Hz repetition rate from a cryogenic cooled diode-pumped Yb:YAG MOPA system

    NASA Astrophysics Data System (ADS)

    Cheng, Xiaojin; Wang, Jianlei; Yang, Zhongguo; Liu, Jin; Li, Lei; Shi, Xiangchun; Huang, Wenfa; Wang, Jiangfeng; Chen, Weibiao

    2015-02-01

    Diode-pumped solid state laser system based on cryogenic Yb:YAG active-mirror scheme are presented with recent energy output. With improved optical design, 6.05J/1Hz pulse energy is achieved and a conceptual design with 30J output energy is theoretical simulated. The doubling efficiency of YCa4O (BO3)(YCOB) crystal is also discussed in this paper.

  14. Cation and anion radicals of (5,15-dimethyl-2,3,7,8,12,13,17,18-octaethyl-5H,15H-porphinato)nickel(II). Comparison of the nickel complexes of porphodimethene and chlorin chromophores

    SciTech Connect

    Renner, M.W.; Buchler, J.W.

    1995-05-18

    There are three possible stereoisomers for Ni(II) porphodimethenes which are related by the stereochemistry of the alkyl groups at the C{sub 5} and C{sub 15} positions. These isomers are denoted syn-axial, syn-sequential, and anti, of which the syn-axial isomer is the most stable. We present here the electrochemical, optical, and EPR properties of the one-electron oxidation and reduction products of 5,15-dimethyl-2,3,7,8,12,13,17,18-octaethyl-5H,15H-porphina nickel(II){sup 24} to investigate how the electronic and structural differences between Ni(II) chlorins and porphodimethenes alter the physical properties of these dihydroporphyrins. 67 refs., 3 figs., 1 tab.

  15. Reconstituted high density lipoprotein mediated targeted co-delivery of HZ08 and paclitaxel enhances the efficacy of paclitaxel in multidrug-resistant MCF-7 breast cancer cells.

    PubMed

    Zhang, Fangrong; Wang, Xiaoyi; Xu, Xiangting; Li, Min; Zhou, Jianping; Wang, Wei

    2016-09-20

    In the past decades, reconstituted high density lipoprotein (rHDL) has been successfully developed as a drug carrier since the enhanced HDL-lipids uptake is demonstrated in several human cancers. In this paper, rHDL, for the first time, was utilized to co-encapsulate two hydrophobic drugs: an anticancer drug, paclitaxel (PTX), and a new reversal agent for P-gp (P-glycoprotein)-mediated multidrug resistance (MDR) of cancer, N-cyano-1-[(3,4-dimethoxyphenyl)methyl]-3,4-dihydro-6,7-dimethoxy-N'-octyl-2(1H)-isoquinoline-carboximidamide (HZ08). We proposed this drug co-delivery strategy to reverse PTX resistance. The study aimed to develop a biomimetic nanovector, reconstituted high density lipoprotein (rHDL), mediating targeted PTX-HZ08 delivery for cancer therapy. Using sodium cholate dialysis method, we successfully formulated dual-agent co-delivering rHDL nanoparticles (PTX-HZ08-rHDL NPs) with a typical spherical morphology, well-distributed size (~100nm), high drug encapsulation efficiency (approximately 90%), sustained drug release properties and exceptional stability even after storage for 1month or incubation in 10% fetal bovine serum (FBS) DMEM for up to 2days. Results demonstrated that PTX-HZ08-rHDL NPs significantly enhanced anticancer efficacy in vitro, including higher cytotoxicity and better ability to induce cell apoptosis against both PTX-sensitive and -resistant MCF-7 human breast cancer cell lines (MCF-7 and MCF-7/PTX cells). Mechanism studies demonstrated that these improvements could be correlated with increased cellular uptake of PTX mediated by scavenger receptor class B type I (SR-BI) as well as prolonged intracellular retention of PTX due to the HZ08 mediated drug-efflux inhibition. In addition, in vivo investigation showed that the PTX-HZ08-rHDL NPs were substantially safer, have higher tumor-targeted capacity and have stronger antitumor activity than the corresponding dosage of paclitaxel injection. These findings suggested that rHDL NPs could

  16. Aminergic control of high-frequency (approximately 200 Hz) network oscillations in the hippocampus of the behaving rat.

    PubMed

    Ponomarenko, Alexei A; Knoche, Anja; Korotkova, Tatiana M; Haas, Helmut L

    2003-09-11

    Hippocampal high-frequency (200 Hz, 'ripple') oscillations were recorded in the CA1 area of behaving rats. The histamine H1-receptor antagonist pyrilamine facilitated while the H2-antagonist zolantidine (5 mg/kg i.p) transiently decreased ripple occurrence. Thioperamide, an H3 antagonist, had no effect. The 5-HT1A-receptor antagonist WAY100635 (50 microg i.c.v.) reduced the occurrence and the intrinsic frequency of ripples. The 5-HT3-receptor antagonist Y-25130 (i.c.v.) increased the number but reduced the amplitude of ripples. All the treatments affected sharp-waves and ripple oscillations to the same extent. Changes of ripple occurrence were not secondary to alterations of behavior. In the light of these divergent actions via different receptor subtypes the net effect of aminergic innervations will be determined by their state-dependent activities and mutual interactions as well as receptor localizations. PMID:12902028

  17. Fs-lentotomy: first in vivo studies on rabbit eyes with a 100 kHz laser system

    NASA Astrophysics Data System (ADS)

    Schumacher, S.; Oberheide, U.; Fromm, M.; Ertmer, W.; Gerten, G.; Wegener, A.; Lubatschowski, H.

    2008-02-01

    Up to now reading glasses are the conventional treatment of presbyopia, an age related effect for every human. According to the Helmholtz theory the reason for the development of accommodative loss is a decreasing elasticity of the lens due to the increasing sclerosis. Since the ciliary muscle and the lens capsule remain active and elastic the whole life, a possible treatment could be the increase of the flexibility by creating gliding planes with fs-laser pulses. flexibility of ex vivo porcine as well as human donor lenses with a laboratory laser system. We will present new results with a compact 100 kHz repetition rate turn key laser system which speeds up the treatment time by a factor of 10. This will offer the opportunity for future clinical trials. Furthermore first in-vivo results on rabbits are presented.

  18. Gas-Phase Condensation Reactions of SixOyHz- Oxyanions with H2O

    SciTech Connect

    Groenewold, Gary Steven; Scott, Jill Rennee; Gianotto, Anita Kay; Hodges, Brittany DM; Kessinger, Glen Frank; Benson, Michael Timothy; Wright, J. B.

    2001-09-01

    Water was reacted with gas-phase oxyanions having the general composition SixOyHz- that were formed and isolated in an ion trap-secondary ion mass spectrometer (IT-SIMS). The radical SiO2- reacted slowly with H2O to abstract HO, forming SiO3H-, at a rate of 8 × 10-13 cm3 molecule-1 s-1, corresponding to an efficiency of about 0.03% compared with the theoretical collision rate constant (average dipole orientation). The product ion SiO3H- underwent a consecutive condensation reaction with H2O to form SiO4H3- at a rate that was approximately 0.4-0.7% efficient. SiO4H3- did not undergo further reaction with water. The multiple reaction pathways by which radical SiO3- reacted with H2O were kinetically modeled using a stochastic approach. SiO3- reacted with water by three parallel reaction pathways: (1) abstraction of a radical H to form SiO3H-, which then reacted with a second H2O to form SiO4H3-; (2) abstraction of a radical OH to form SiO4H-, which further reacted by consecutive H abstractions to form SiO4H2- and then SiO4H3-; and (3) condensation with H2O to form SiO4H2-, which subsequently abstracted a radical H from a second H2O to form SiO4H3-. In all of these reactions, the rate constants were determined to be very slow, as determined by both direct measurement and stochastic modeling. For comparison, the even electron ion Si2O5H- was also investigated: it underwent condensation with H2O to form Si2O6H3-, with a rate constant corresponding to 50% efficiency. The reactions were also modeled using ab initio calculations at the UB3LYP/6-311+G(2d,p) level. Addition of H2O to SiO3-, SiO3H-, and Si2O5H- was calculated to be approximately 42, 45, and 55 kcal mol-1 exothermic, respectively, and encountered low activation barriers. Modeling of SiO2- and SiO3- reactions with H2O failed to produce radical abstraction reaction pathways observed in the IT-SIMS, possibly indicating that alternative reaction mechanisms are operative.

  19. kHz femtosecond laser-plasma hard X-ray and fast ion source

    NASA Astrophysics Data System (ADS)

    Thoss, A.; Korn, G.; Richardson, M. C.; Faubel, M.; Stiel, H.; Voigt, U.; Siders, C. W.; Elsaesser, T.

    2002-04-01

    We describe the first demonstration of a new stable, kHz femtosecond laser-plasma source of hard x-ray continuum and Kα emission using a thin liquid metallic jet target. kHz femtosecond x-ray sources will find many applications in time-resolved x-ray diffraction and microscopy studies. As high intensity lasers become more compact and operate at increasingly high repetition-rates, they require a target configuration that is both repeatable from shot-to-shot and is debris-free. We have solved this requirement with the use of a fine (10-30 μm diameter) liquid metal jet target that provides a pristine, unperturbed filament surface at rates >100 kHz. A number of liquid metal targets are considered. We will show hard x-ray spectra recorded from liquid Ga targets that show the generation of the 9.3 keV and 10.3 keV, Kα and Kβ lines superimposed on a multi-keV Bremsstrahlung continuum. This source was generated by a 50fs duration, 1 kHz, 2W, high intensity Ti:Sapphire laser. We will discuss the extension of this source to higher powers and higher repetition rates, providing harder x-ray emission, with the incorporation of pulse-shaping and other techniques to enhance the x-ray conversion efficiency. Using the same liquid target technology, we have also demonstrated the generation of forward-going sub-MeV protons from a 10 μm liquid water target at 1 kHz repetition rates. kHz sources of high energy ions will find many applications in time-resolved particle interaction studies, as well as lead to the efficient generation of short-lived isotopes for use in nuclear medicine and other applications. The protons were detected with CR-39 track detectors both in the forward and backward directions up to energies of ~500 keV. As the intensity of compact high repetition-rate lasers sources increase, we can expect improvements in the energy, conversion efficiency and directionality to occur. The impact of these developments on a number of fields will be discussed. As compact

  20. Evolution of CPMAS under fast magic-angle-spinning at 100 kHz and beyond.

    PubMed

    Wickramasinghe, Ayesha; Wang, Songlin; Matsuda, Isamu; Nishiyama, Yusuke; Nemoto, Takahiro; Endo, Yuki; Ishii, Yoshitaka

    2015-11-01

    This article describes recent trends of high-field solid-state NMR (SSNMR) experiments for small organic molecules and biomolecules using (13)C and (15)N CPMAS under ultra-fast MAS at a spinning speed (νR) of 80-100kHz. First, we illustrate major differences between a modern low-power RF scheme using UFMAS in an ultra-high field and a traditional CPMAS scheme using a moderate sample spinning in a lower field. Features and sensitivity advantage of a low-power RF scheme using UFMAS and a small sample coil are summarized for CPMAS-based experiments. Our 1D (13)C CPMAS experiments for uniformly (13)C- and (15)N-labeled alanine demonstrated that the sensitivity per given sample amount obtained at νR of 100kHz and a (1)H NMR frequency (νH) of 750.1MHz is ~10 fold higher than that of a traditional CPMAS experiment obtained at νR of 20kHz and νH of 400.2MHz. A comparison of different (1)H-decoupling schemes in CPMAS at νR of 100kHz for the same sample demonstrated that low-power WALTZ-16 decoupling unexpectedly displayed superior performance over traditional low-power schemes designed for SSNMR such as TPPM and XiX in a range of decoupling field strengths of 5-20kHz. Excellent (1)H decoupling performance of WALTZ-16 was confirmed on a protein microcrystal sample of GB1 at νR of 80kHz. We also discuss the feasibility of a SSNMR microanalysis of a GB1 protein sample in a scale of 1nmol to 80nmol by (1)H-detected 2D (15)N/(1)H SSNMR by a synergetic use of a high field, a low-power RF scheme, a paramagnetic-assisted condensed data collection (PACC), and UFMAS.

  1. Acute and subchronic toxicity of 20  kHz and 60  kHz magnetic fields in rats

    PubMed Central

    Oshima, Atsushi; Shibuya, Kazumoto; Mitani, Takashi; Negishi, Tadashi

    2015-01-01

    Abstract Despite increasing use of intermediate frequency (IF) magnetic fields (MFs) in occupational and domestic settings, scientific evidence necessary for health risk assessments of IF MF is insufficient. Male and female Crl:CD(SD) rats (12 per sex per group) were exposed to 20 kHz, 0.20 mT(root mean square, rms) or 60 kHz, 0.10 mT(rms) sinusoidal MFs for 22 h day−1 for 14 days (acute) or 13 weeks (subchronic). Experiments were duplicated for each frequency to ensure outcome reproducibility, and examinations were blinded for quality assurance. All rats survived without significant clinical signs until the end of experiments. Some changes in body weight between the MF‐exposed and control groups were observed over the course of exposure, although the directions of the changes were inconsistent and not statistically significant after subchronic exposure. There were significant differences between MF‐exposed and control groups in some organ weights and parameters in hematology and clinical chemistry, but these were minor in magnitude and not repeated in duplicate experiments. Histopathological findings reflecting toxicity were sporadic. Frequencies of other findings were similar to historic data in this rat strain, and findings had no specific relationship to changes in organ weight or parameters of hematology and clinical chemistry in each animal. The changes observed throughout this study were considered biologically isolated and were attributable to chance associations rather than to MF exposure. The results, in particular the histopathological evidence, indicate an absence of toxicity in IF MF‐exposed rats and do not support the hypothesis that IF MF exposure produces significant toxicity. Copyright © 2015. The Authors. Journal of Applied Toxicology Published by John Wiley & Sons Ltd. PMID:25982482

  2. Effects of 60-Hz electric fields on living plants exposed for extended periods. Final report

    SciTech Connect

    Not Available

    1985-07-01

    The effects of intense 60-Hz electric fields were studied by exposing plants of five kinds (crops) for extended periods in a special greenhouse where cultural and environmental factors could be controlled. Plant populations and densities simulated field conditions. While exposed, plants of all crops germinated satisfactorily, and plants of sweet corn and wheat completed their life cycles and produced viable seed. Plants of alfalfa and tall fescue were at the early bloom stage when harvested. Exposure of plants of five kinds to electric fields had no statistically significant effects on seed germination, seedling growth, plant growth, phenology, flowering, seed set, biomass production, plant height, leaf area, plant survival, and nodulation. Exposure to 60-Hz electric fields resulted in very limited damage to terminal leaf tips, awns, and corn tassels, particularly at fields of 30 kV/m or greater. 47 refs., 36 figs., 44 tabs.

  3. Dual-rod, 100 Hz, 388 mJ nanosecond Nd:YAG oscillator.

    PubMed

    Liu, Qiang; Liu, Jianhui; Gong, Mali

    2011-03-10

    We report a large mode volume unstable resonator working at 100 Hz. The resonator is combined with a variable reflectivity convex mirror and a high-reflective convex mirror. The cavity mirrors are used to compensate for the thermal lensing effect of the two Nd:YAG laser rods, which are pumped by high-energy high-repetition-rate diode lasers. A 90° quartz rotator is placed between the two laser rods to compensate for the thermal depolarization. In the experiment, output of as high as 388 mJ is obtained at 100 Hz with slope efficiency of 36%. The pulse width is 15 ns, and the beam quality factor is M(x)(2)=3.2, M(y)(2)=2.8. PMID:21394190

  4. 100 kHz thousand-frame burst-mode planar imaging in turbulent flames.

    PubMed

    Michael, James B; Venkateswaran, Prabhakar; Miller, Joseph D; Slipchenko, Mikhail N; Gord, James R; Roy, Sukesh; Meyer, Terrence R

    2014-02-15

    High-repetition-rate, burst-mode lasers can achieve higher energies per pulse compared with continuously pulsed systems, but the relatively few number of laser pulses in each burst has limited the temporal dynamic range of measurements in unsteady flames. A fivefold increase in the range of timescales that can be resolved by burst-mode laser-based imaging systems is reported in this work by extending a hybrid diode- and flashlamp-pumped Nd:YAG-based amplifier system to nearly 1000 pulses at 100 kHz during a 10 ms burst. This enables an unprecedented burst-mode temporal dynamic range to capture turbulent fluctuations from 0.1 to 50 kHz in flames of practical interest. High pulse intensity enables efficient conversion to the ultraviolet for planar laser-induced fluorescence imaging of nascent formaldehyde and other potential flame radicals.

  5. Performance of a 30-kV, 1-kHz, nanosecond source

    SciTech Connect

    Cravey, W.R.; Freytag, K.; Goerz, D.

    1992-06-01

    An existing pulser at LLNL was modified to increase its repetition rate to 1000 Hz. Spark gap recovery measurements were made for both the Marx and the Blumlein output switches. Recovery times of less than 1 ms were recorded without gas flow in the switch chambers. Low pressure synthetic air was used as the switch dielectric. Longer recovery times were necessary to over-voltage the switch. The output of the pulser was used to drive a log-periodic-dipole-array. Measurements were made on the transmitted pulses in an anechoic chamber and yielded a center frequency of 80 MHz. This paper describes the modifications made on the pulse generator, discusses the spark gap recovery data, and summarizes the performance of the pulser at 1 kHz. In addition, a brief description of the antenna is given along with the field measurements that were made in the EMPEROR facility.

  6. Multi-mJ, kHz, ps deep-ultraviolet source.

    PubMed

    Chang, Chun-Lin; Krogen, Peter; Liang, Houkun; Stein, Gregory J; Moses, Jeffrey; Lai, Chien-Jen; Siqueira, Jonathas P; Zapata, Luis E; Kärtner, Franz X; Hong, Kyung-Han

    2015-02-15

    We demonstrate a 0.56-GW, 1-kHz, 4.2-ps, 2.74-mJ deep-ultraviolet (DUV) laser at ∼257.7  nm with a beam propagation factor (M2) of ∼2.54 from a frequency-quadrupled cryogenic multi-stage Yb-doped chirped-pulse amplifier. The frequency quadrupling is achieved using LiB3O5 and β-BaB2O4 crystals for near-infrared (NIR)-to-green and green-to-DUV conversion, respectively. An overall NIR-to-DUV efficiency of ∼10% has been achieved, which is currently limited by the thermal-induced phase mismatching and the DUV-induced degradation of transmittance. To the best of our knowledge, this is the highest peak-power picosecond DUV source from a diode-pumped solid-state laser operating at kHz repetition rates.

  7. Implications of a 20-Hz Booster cycle-rate for Slip-stacking

    SciTech Connect

    Eldred, Jeffrey; Zwaska, Robert

    2014-06-10

    We examine the potential impacts to slip-stacking from a change of the Booster cycle-rate from 15- to 20-Hz. We find that changing the Booster cycle-rate to 20-Hz would greatly increase the slip-stacking bucket area, while potentially requiring greater usage of the Recycler momentum aperture and additional power dissipation in the RF cavities. In particular, the losses from RF interference can be reduced by a factor of 4-10 (depending on Booster beam longitudinal parameters). We discuss the aspect ratio and beam emittance requirements for efficient slip-stacking in both cycle-rate cases. Using a different injection scheme can eliminate the need for greater momentum aperture in the Recycler.

  8. Orbit response matrix measurements for 10Hz global orbit feedback in RHIC

    SciTech Connect

    Liu, C.; Minty, M.

    2010-10-01

    The 10 Hz global orbit feedback system (gofb) was designed to correct the 10 Hz horizontal beam perturbations in both rings that are suspected to be caused by vibrations of the final focusing quadrupoles (triplets). The full system envisioned for Run-11 consists of 36 BPMs, corresponding to 2 per triplet in each of the 12 triplet locations and two in each of the 6 arcs, and 1 dipole corrector at each triplet location for a total of 12 correctors. Prototype testing was successfully carried out during RHIC Run-10 in store condition with 4 new dipole correctors (with independent power supplies) and 8 stripline beam position monitors (BPMs) per accelerator. An SVD-based algorithm was used to compute the applied corrections. For Run-10, the response matrix was provided by W. W. MacKay. The response matrix R relates corrector angles to beam displacements at BPMs.

  9. Discovery of a Neutron Star with Spin Frequency 530 Hz in A1744-361

    NASA Technical Reports Server (NTRS)

    Bhattacharyya, Sudip; Strohmayer, Tod E.; Markwardt, Craig B.; Swank, Jean H.; Bhattacharyya, Sudip

    2005-01-01

    We report the detection with the Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) of 530 Hz burst oscillations in a thermonuclear (Type I) burst from the transient X-ray source A1744-361. This is only the second burst ever observed from this source, and the first to be seen in any detail. Our results confirm that A1744-361 is a low mass X-ray binary (LMXB) system harboring a rapidly rotating neutron star. The oscillations are first detected along the rising edge of the burst, and show evidence for frequency evolution of a magnitude similar to that seen in other burst sources. The modulation amplitude and its increase with photon energy are also typical of burst oscillations. The lack of any strong indication of photospheric radius expansion during the burst suggests a 9 kpc upper limit of the source distance. We also find energy dependent dips, establishing A1744-361 as a high inclination, dipping LMXB. The timescale between the two episodes of observed dips suggests an orbital period of approx. 97 min. We have also detected a 2 - 4 Hz quasi-periodic-oscillation (QPO) for the first time from this source. This QPO appears consistent with approx. 1 Hz QPOs seen from other high inclination systems. We searched for kilohertz QPOs, and found a suggestive 2.3 sigma feature at 800 Hz in one observation. The frequency, strength and quality factor are consistent with that of a lower frequency kilohertz QPO, but the relatively low significance argues for caution, so we consider this a tentative detection requiring confirmation.

  10. Time dependence of 50 Hz magnetic fields in apartment buildings with indoor transformer stations.

    PubMed

    Yitzhak, Nir-Mordechay; Hareuveny, Ronen; Kandel, Shaiela; Ruppin, Raphael

    2012-04-01

    Twenty-four hour measurements of 50 Hz magnetic fields (MFs) in apartment buildings containing transformer stations have been performed. The apartments were classified into four types, according to their location relative to the transformer room. Temporal correlation coefficients between the MF in various apartments, as well as between MF and transformer load curves, were calculated. It was found that, in addition to their high average MF, the apartments located right above the transformer room also exhibit unique temporal correlation properties.

  11. A 100 microsec, reliable, 10 Hz pulsed supersonic molecular beam source

    NASA Technical Reports Server (NTRS)

    Byer, R. L.; Duncan, M. D.

    1981-01-01

    A 10-Hz repetition rate, 100-microsec duration, reliable pulsed supersonic molecular beam source is described. Mechanical and electrical design of the pulsed valve are given in detail. Characteristics of the supersonic expansion obtained using coherent anti-Stokes Raman spectroscopy in acetylene are presented. They include pulse shape, gas rotational and translational cooling as a function of distance from the nozzle, clustering effects, and shock heating at the leading edge of the pulse.

  12. Superradiance on the mHz linewidth clock transition in 87Sr

    NASA Astrophysics Data System (ADS)

    Norcia, Matthew; Winchester, Matthew; Cline, Julia; Thompson, James

    2016-05-01

    In this talk, I will discuss our recent experimental explorations of superradiant emission from the mHz linewidth clock transition in an ensemble of cold 87 Sr atoms confined within a high-finesse optical cavity. Recent proposals suggest that superradiant lasers based on such dipole-forbidden transitions in alkaline earth atoms could achieve linewidths below the current state of the art, with reduced sensitivity to environmental perturbations.

  13. Weighted SVD algorithm for close-orbit correction and 10 Hz feedback in RHIC

    SciTech Connect

    Liu C.; Hulsart, R.; Marusic, A.; Michnoff, R.; Minty, M.; Ptitsyn, V.

    2012-05-20

    Measurements of the beam position along an accelerator are typically treated equally using standard SVD-based orbit correction algorithms so distributing the residual errors, modulo the local beta function, equally at the measurement locations. However, sometimes a more stable orbit at select locations is desirable. In this paper, we introduce an algorithm for weighting the beam position measurements to achieve a more stable local orbit. The results of its application to close-orbit correction and 10 Hz orbit feedback are presented.

  14. Stereoscopic Planar Laser-Induced Fluorescence Imaging at 500 kHz

    NASA Technical Reports Server (NTRS)

    Medford, Taylor L.; Danehy, Paul M.; Jones, Stephen B.; Jiang, N.; Webster, M.; Lempert, Walter; Miller, J.; Meyer, T.

    2011-01-01

    A new measurement technique for obtaining time- and spatially-resolved image sequences in hypersonic flows is developed. Nitric-oxide planar laser-induced fluorescence (NO PLIF) has previously been used to investigate transition from laminar to turbulent flow in hypersonic boundary layers using both planar and volumetric imaging capabilities. Low flow rates of NO were typically seeded into the flow, minimally perturbing the flow. The volumetric imaging was performed at a measurement rate of 10 Hz using a thick planar laser sheet that excited NO fluorescence. The fluorescence was captured by a pair of cameras having slightly different views of the flow. Subsequent stereoscopic reconstruction of these images allowed the three-dimensional flow structures to be viewed. In the current paper, this approach has been extended to 50,000 times higher repetition rates. A laser operating at 500 kHz excites the seeded NO molecules, and a camera, synchronized with the laser and fitted with a beam-splitting assembly, acquires two separate images of the flow. The resulting stereoscopic images provide three-dimensional flow visualizations at 500 kHz for the first time. The 200 ns exposure time in each frame is fast enough to freeze the flow while the 500 kHz repetition rate is fast enough to time-resolve changes in the flow being studied. This method is applied to visualize the evolving hypersonic flow structures that propagate downstream of a discrete protuberance attached to a flat plate. The technique was demonstrated in the NASA Langley Research Center s 31-Inch Mach 10 Air Tunnel facility. Different tunnel Reynolds number conditions, NO flow rates and two different cylindrical protuberance heights were investigated. The location of the onset of flow unsteadiness, an indicator of transition, was observed to move downstream during the tunnel runs, coinciding with an increase in the model temperature.

  15. Ion Molecule Reactions of Gas-Phase Chromium Oxyanions:CrxOyHz- + O2

    SciTech Connect

    Anita K. Gianotto; Brittany D. M. Hodges; Peter de B. Harrington; Anthony Appelhans; John E. Olson; Gary S. Groenewold

    2003-10-01

    Chromium oxyanions, CrxOyHz-, were generated in the gas-phase using a quadrupole ion trap secondary ion mass spectrometer (IT-SIMS), where they were reacted with O2. Only CrO2- of the Cr1OyHz- envelope was observed to react with oxygen, producing primarily CrO3-. The rate constant for the reaction of CrO2- with O2 was 38% of the Langevin collision constant at 310 K. CrO3-, CrO4-, and CrO4H- were unreactive with O2 in the ion trap. In contrast, Cr2O4- was observed to react with O2 producing CrO3- + CrO3 via oxidative degradation at a rate that was 15% efficient. The presence of background water facilitated the reaction of Cr2O4- + H2O to form Cr2O5H2-; the hydrated product ion Cr2O5H2- reacted with O2 to form Cr2O6- (with concurrent elimination of H2O) at a rate that was 6% efficient. Cr2O5- also reacted with O2 to form Cr2O7- (4% efficient) and Cr2O6- + O (2% efficient); these reactions proceeded in parallel. By comparison, Cr2O6- was unreactive with O2, and in fact, no further O2 addition could be observed for any of the Cr2O6Hz- anions. Generalizing, CrxOyHz- species that have low coordinate, low oxidation state metal centers are susceptible to O2 oxidation. However, when the metal coordination is >3, or when the formal oxidation state is =5, reactivity stops.

  16. Ozone generation in a kHz-pulsed He-O2 capillary dielectric barrier discharge operated in ambient air

    NASA Astrophysics Data System (ADS)

    Sands, Brian L.; Ganguly, Biswa N.

    2013-12-01

    The generation of reactive oxygen species using nonequilibrium atmospheric pressure plasma jet devices has been a subject of recent interest due to their ability to generate localized concentrations from a compact source. To date, such studies with plasma jet devices have primarily utilized radio-frequency excitation. In this work, we characterize ozone generation in a kHz-pulsed capillary dielectric barrier discharge configuration comprised of an active discharge plasma jet operating in ambient air that is externally grounded. The plasma jet flow gas was composed of helium with an admixture of up to 5% oxygen. A unipolar voltage pulse train with a 20 ns pulse risetime was used to drive the discharge at repetition rates between 2-25 kHz. Using UVLED absorption spectroscopy centered at 255 nm near the Hartley-band absorption peak, ozone was detected over 1 cm from the capillary axis. We observed roughly linear scaling of ozone production with increasing pulse repetition rate up to a "turnover frequency," beyond which ozone production steadily dropped and discharge current and 777 nm O(5P→5S°) emission sharply increased. The turnover in ozone production occurred at higher pulse frequencies with increasing flow rate and decreasing applied voltage with a common energy density of 55 mJ/cm3 supplied to the discharge. The limiting energy density and peak ozone production both increased with increasing O2 admixture. The power dissipated in the discharge was obtained from circuit current and voltage measurements using a modified parallel plate dielectric barrier discharge circuit model and the volume-averaged ozone concentration was derived from a 2D ozone absorption measurement. From these measurements, the volume-averaged efficiency of ozone production was calculated to be 23 g/kWh at conditions for peak ozone production of 41 mg/h at 11 kV applied voltage, 3% O2, 2 l/min flow rate, and 13 kHz pulse repetition rate, with 1.79 W dissipated in the discharge.

  17. Effects of 60 Hz electric fields on operant and social stress behaviors of nonhuman primates

    SciTech Connect

    Rogers, W.R.; Coelho, A.M. Jr.; Easley, S.P.; Lucas, J.H.; Moore, G.T.; Orr, J.L.; Smith, H.D.; Taylor, L.L.; Tuttle, M.L.

    1987-10-24

    The objective of this program is to investigate, using the baboon as a nonhuman primate surrogate for the human, possible behavioral effects associated with exposure to high intensity 60 Hz electric fields. Results from this program, along with information from experiments conducted elsewhere, will be used by the Department of Energy (DOE) to estimate and evaluate the likelihood of deleterious consequences resulting from exposure of humans to the electric fields associated with power transmission over high voltage lines. This research program consists of four major research projects, all of which have been successfully completed. The first project evaluated the potentially aversive character of exposure to 60 Hz electric fields by determining the threshold intensity that produces escape or avoidance responses. The second project estimated the threshold intensity for detection threshold was 12 kV/m; the range of means was 6 to 16 kV/m. The third project assessed, in separate experiments conducted at 30 and 60 kV/m, effects of chronic exposure to electric fields on the performance of two operant conditioning tasks, fixed ratio (FR), and differential reinforcement of low rate (DRL). In the same two experiments, the fourth project investigated, using the systematic quantitative observational sampling methods of primatology, the possible stress-inducing effects of chronic exposure to 60 Hz electric fields on the behavior of baboons living in small social groups. 131 refs., 87 figs., 123 tabs.

  18. Exposure to 50Hz-sinusoidal electromagnetic field induces DNA damage-independent autophagy.

    PubMed

    Shen, Yunyun; Xia, Ruohong; Jiang, Hengjun; Chen, Yanfeng; Hong, Ling; Yu, Yunxian; Xu, Zhengping; Zeng, Qunli

    2016-08-01

    As electromagnetic field (EMF) is commonly encountered within our daily lives, the biological effects of EMF are of great concern. Autophagy is a key process for maintaining cellular homeostasis, and it can also reveal cellular responses to environmental stimuli. In this study, we aim to investigate the biological effects of a 50Hz-sinusoidal electromagnetic field on autophagy and we identified its mechanism of action in Chinese Hamster Lung (CHL) cells. CHL cells were exposed to a 50Hz sinusoidal EMF at 0.4mT for 30min or 24h. In this study, we found that a 0.4mT EMF resulted in: (i) an increase in LC3-II expression and increased autophagosome formation; (ii) no significant difference in the incidence of γH2AX foci between the sham and exposure groups; (iii) reorganized actin filaments and increased pseudopodial extensions without promoting cell migration; and (iv) enhanced cell apoptosis when autophagy was blocked by Bafilomycin A1. These results implied that DNA damage was not directly involved in the autophagy induced by a 0.4mT 50Hz EMF. In addition, an EMF induced autophagy balanced the cellular homeostasis to protect the cells from severe adverse biological consequences.

  19. Retinoic acid inhibits the cytoproliferative response to weak 50-Hz magnetic fields in neuroblastoma cells

    PubMed Central

    TRILLO, MARÍA ÁNGELES; MARTÍNEZ, MARÍA ANTONIA; CID, MARÍA ANTONIA; ÚBEDA, ALEJANDRO

    2012-01-01

    We previously reported that intermittent exposure to a 50-Hz magnetic field (MF) at 100 μT stimulates cell proliferation in the human neuroblastoma cell line NB69. The present study aimed to investigate whether the magnetic field-induced growth promotion also occurs at a lower magnetic flux density of 10 μT. To this purpose, NB69 cells were subjected for 42 h to intermittent exposure, 3 h on/3 h off, to a 50-Hz MF at a 10 or 100 μT magnetic flux density. The field exposure took place either in the presence or in the absence of the antiproliferative agent retinoic acid. At the end of the treatment and/or incubation period, the cell growth was estimated by hemocytometric counting and spectrophotometric analysis of total protein and DNA contents. Potential changes in DNA synthesis were also assessed through proliferating cell nuclear antigen (PCNA) immunolabeling. The results confirmed previously reported data that a 42-h exposure to a 50-Hz sine wave MF at 100 μT promotes cell growth in the NB69 cell line, and showed that 10 μT induces a similar proliferative response. This effect, which was significantly associated and linearly correlated with PCNA expression, was abolished by the presence of retinoic acid in the culture medium. PMID:23292364

  20. 3.5kHz Profiling with Vertically Separated Source and Receiver

    NASA Astrophysics Data System (ADS)

    Bolmer, S. T.; Hoskins, H.; Stephen, R. A.; Leg 200 Shipboard Scientific Party, .

    2003-12-01

    The spatial resolution of hull mounted 3.5kHz echo sounding systems is often limited in deep water by the large footptint (Fresnel zone) of the insonifying energy on the seafloor. On ODP Leg 200 at Site 1224, we tested a system that could be used from the drillship while on station to improve resolution. In 4970 m water depth, a 3.5 kHz pinger was mounted on the video camera frame and lowered down the drill string to a few meters above the seafloor. The ship's 3.5 kHz receiver recorded the returns. Having the source and receiver at differing distances above the seafloor provides two advantages: 1) the area returning reflections is greatly reduced, 2) the amplitudes of the sub-seafloor reflections are less affected by the spreading effect. Reflections were observed to 38 ms beneath the seafloor on lowerings at three closely spaced holes. The heave of the ship and camera frame shifted the travel times of the reflection sequences. A level-discriminator and correlation MatLab routine was used to align the traces and to stack them to enhance signal. The reflections showed good correlation with the limited geotechnical data obtained from the sediment cores. Although tested from the drill ship this system could be used to provide a low cost, shallow penetration profiling system from ROV's and AUV's. This work was supported by a grant from JOI-USSAC.

  1. Discriminating ripple-fire explosions with high frequency (>20 Hz) data

    SciTech Connect

    Carr, D.B.; Garbin, H.D.

    1996-04-01

    With a Comprehensive Test Ban (CTB), discriminating ripple-fired explosions from mining operations becomes important. Different methods have been proposed to discriminate these explosions, most of which use the modulations seen in the spectra of ripple-fired blasts. The Deployable Seismic Verification System (DSVS) in Wyoming records data at frequencies up to 50 Hz, and provides an opportunity to determine if there are any operational benefits to discriminate ripple-fired explosions from using high frequency (> 20 Hz) data. We collected a database of 646 events consisting of 118 known earthquakes, 1 known rockburst, 176 known ripple-fired quarry blasts and 351 unknown signals. Binary spectrograms for each event were calculated using a 2.5 second window, 5/8 overlap and 10% cosine window. We used a frequency band of 0 to 50 Hz. A blind test was done to choose events that appeared to have spectral banding indicative of ripple-fire explosions. One hundred fifty one events were picked as ripple-fire explosions by both authors; 59 of these events are known quarry blasts. To remove the ambiguities introduced using human analysts, we calculated an average binary spectrum for each event following a method similar to Wuster (1993). A criterion was developed so that events with six or more peaks over 0.8 and/or nulls under 0.2 was declared a ripple-fire explosion. With this method, 251 events were chosen as ripple-fire explosions, 91 of them known quarry blasts.

  2. Measuring ground deformations with 1-Hz GPS data: the 2003 Tokachi-oki earthquake (preliminary report)

    NASA Astrophysics Data System (ADS)

    Irwan, Meilano; Kimata, Fumiaki; Hirahara, Kazuro; Sagiya, Takeshi; Yamagiwa, Atsushi

    2004-03-01

    We analyzed 1-Hz GPS data observed at 14 stations of the GPS Earth Observation Network (GEONET) of the Geographical Survey Institute, Japan, associated with the 2003 M JMA 8.1 Tokachi-oki earthquake, which occurred at the Kurile Trench. The GPS stations are located 70-240 km away from the epicenter. GPS data clearly captured rapid co-seismic ground displacements. At a GPS station 70 km away from the epicenter, coseismic displacements started 15 seconds after the origin time, and after 40 seconds at the stations 240 km away. Observed displacement amplitude exceeded 20 cm at GPS sites 240 km away from the epicenter. Displacement amplitudes attenuate with time and distance from the epicenter, oscillating with periods of 40-60 seconds. We compared the 1-Hz GPS data and displacement seismogram integrated from strong ground motion data, which showed fairly good agreements. In spite of careful screening of 1-Hz GPS data during 30 minutes preceding the main shock, no significant preseismic deformation over 1 cm in the horizontal components was recorded. 30 second sampling GPS data at 14 sites during 20 hours preceding the main shock did not show any significant pre-seismic deformation, either. These results indicate that pre-seismic strain change, if any, was smaller than 0.5-1.0×10-7 before the 2003 Tokachi-oki earthquake.

  3. Reliability of electric response audiometry using 80 Hz auditory steady-state responses.

    PubMed

    Kaf, Wafaa A; Sabo, Diane L; Durrant, John D; Rubinstein, Elaine

    2006-08-01

    The reliability of the Auditory Steady State Response (ASSR) has not been thoroughly evaluated despite its recent application as a clinical tool for threshold estimation. The purpose of this study was to examine test-retest (TR) reliability of ASSR threshold estimates in an empirical research design. The ASSR, tested using modulation frequencies approximately 80 Hz and above, was evaluated against pure tone audiometry (PTA), and the slow vertex potential (SVP, N1-P2). Sixteen normal-hearing young female adults were tested twice, one week apart. Varying degrees of sensorineural hearing loss of a notched configuration were simulated with filtered masking noise. Test-retest reliability was assessed using Pearson-product moment correlation analysis, supplemented by other post-hoc analyses. Results demonstrated moderately strong TR reliability for ASSR at 1000, 2000 and 4000 Hz (r = 0.83-0.93); however, the reliability of ASSR at 500 Hz was weaker (r = 0.75). Results suggest that ASSR-ERA is a reliable test at mid-high frequencies, at least with the configuration and degrees of simulated sensorineural hearing loss examined in this study. PMID:17005490

  4. A novel particle separation technique using 20-kHz-order ultrasound irradiation in water

    NASA Astrophysics Data System (ADS)

    Muramatsu, Hiroya; Yanai, Sayuri; Mizushima, Yuki; Saito, Takayuki

    2015-12-01

    Ultrasound techniques such as washing, fine-particle manipulation and mixing have been investigated. MHz-band ultrasound was usually used in the previous work, and studies of kHz-order ultrasound are very rare. In the usual manipulation technique, μm- order particles are targeted due to wavelength limitations. We discovered an interesting phenomenon that holds promise for a novel particle separation technique using kHz-order ultrasound. Here, particles with sub-mm- or mm-order diameters were flocculated into a swarm in water irradiated by 20-kHz ultrasound. To develop a practical separation process, we investigated the stationary position and dia. of the particle swarms and the sound- pressure profiles in a vessel, as well as the flocculation mechanism, by varying the irradiation frequency, water level, particle diameter and particle amount. The primary stationary position corresponded to the wavelength calculated from the resonant frequency regardless of the particle diameter. Subtle changes in the frequency and water level resulted in a significant change in the stationary position. Based on these results, we propose a new separation process based on the particle diameter for sub-mm- or mm-order particles.

  5. Continuous hydroxyl radical planar laser imaging at 50 kHz repetition rate.

    PubMed

    Hammack, Stephen; Carter, Campbell; Wuensche, Clemens; Lee, Tonghun

    2014-08-10

    This study demonstrates high-repetition-rate planar laser-induced fluorescence (PLIF) imaging of hydroxyl radicals (OH) in flames at a continuous framing rate of 50 kHz. A frequency-doubled dye laser is pumped by the second harmonic of an Nd:YAG laser to generate laser radiation near 283 nm with a pulse width of 8 ns and rate of 50 kHz. Fluorescence is recorded by a two-stage image intensifier and complementary metal-oxide-semiconductor camera. The average power of the 283 nm beam reaches 7 W, yielding a pulse energy of 140 μJ. Both a Hencken burner and a DC transient-arc plasmatron are used to produce premixed CH4/air flames to evaluate the OH PLIF system. The average signal-to-noise ratio for the Hencken burner flame is greater than 20 near the flame front and greater than 10 further downstream in a region of the flame near equilibrium. Image sequences of the DC plasmatron discharge clearly illustrate development and evolution of flow features with signal levels comparable to those in the Hencken burner. The results are a demonstration of the ability to make high-fidelity OH PLIF measurements at 50 kHz using a Nd:YAG-pumped, frequency-doubled dye laser. PMID:25320935

  6. Exposure to 50Hz-sinusoidal electromagnetic field induces DNA damage-independent autophagy.

    PubMed

    Shen, Yunyun; Xia, Ruohong; Jiang, Hengjun; Chen, Yanfeng; Hong, Ling; Yu, Yunxian; Xu, Zhengping; Zeng, Qunli

    2016-08-01

    As electromagnetic field (EMF) is commonly encountered within our daily lives, the biological effects of EMF are of great concern. Autophagy is a key process for maintaining cellular homeostasis, and it can also reveal cellular responses to environmental stimuli. In this study, we aim to investigate the biological effects of a 50Hz-sinusoidal electromagnetic field on autophagy and we identified its mechanism of action in Chinese Hamster Lung (CHL) cells. CHL cells were exposed to a 50Hz sinusoidal EMF at 0.4mT for 30min or 24h. In this study, we found that a 0.4mT EMF resulted in: (i) an increase in LC3-II expression and increased autophagosome formation; (ii) no significant difference in the incidence of γH2AX foci between the sham and exposure groups; (iii) reorganized actin filaments and increased pseudopodial extensions without promoting cell migration; and (iv) enhanced cell apoptosis when autophagy was blocked by Bafilomycin A1. These results implied that DNA damage was not directly involved in the autophagy induced by a 0.4mT 50Hz EMF. In addition, an EMF induced autophagy balanced the cellular homeostasis to protect the cells from severe adverse biological consequences. PMID:27177844

  7. Dependence of kHz quasi-periodic oscillation frequencies on accretion-related parameters

    NASA Astrophysics Data System (ADS)

    Erkut, M. Hakan; Catmabacak, Onur; Duran, Sivan; Çatmabacak, Önder

    2016-07-01

    To study the possible dependence of kHz QPO frequencies on the parameters such as the mass accretion rate, the surface magnetic field strength, mass, and radius of the neutron star, we consider the up-to-date distribution of neutron star LMXBs in the kHz QPO frequency versus X-ray luminosity plane. We confirm the absence of any correlation between QPO frequencies and luminosity in the ensemble of LMXBs. Searching for the dependence of QPO data on accretion-related parameters, we find a correlation between the lower kHz QPO frequency and the parameter combining mass accretion rate with magnetic field strength. The correlation cannot be adequately described by a simple power law due to observed scattering of individual source data in the ensemble of Z and atoll sources. Based on disk-magnetosphere boundary region, the model function for QPO frequency can delineate the correlation taking into account the scattering of individual sources. In addition to mass accretion rate and magnetic field strength, the model function also depends on the radial width of the boundary region near the magnetopause. Modelling the variation of the width with mass accretion rate, we also provide an explanation for the parallel tracks phenomenon observed in the case of individual sources.

  8. Immunological and biochemical effects of 60 Hz electric and magnetic fields in humans

    SciTech Connect

    Fotopoulos, S.S.; Graham, C.

    1990-01-01

    Demand for electric energy increased at an annual average rate of 7.5% between 1912 and 1971. In order to meet this demand, utility companies have increased the number and size of their generating units and the operating voltages employed in overhead transmission lines. Recently public concern has been expressed about possible risks to human health, function, and well-being arising from exposure to the electric and magnetic fields associated with overhead transmission line voltage. The Department of Energy funded the present project to investigate the effects of 60-Hz electric and magnetic fields on critically important immunological, biochemical, and hematological variables. Inclusion of such variables will be of great value in assessing the effects of 60-Hz fields on human health and welfare, and will provide results comparable to ongoing animal studies. The scope of this project includes six major goals: development of systems for incorporating biochemistry, hematology, and immunology data collection into the procedures already developed for the performance and physiology study funded by the New York State Overhead Power Lines Project; development of sample tracking and quality assurance procedures for project data; methods development and setting up of all procedures for performing assays; collecting data; carrying out assays according to the procedures defined; and statistically evaluating and interpreting the effects of 60-Hz exposure on hematological, biochemical, and immunological parameters. 3 tabs.

  9. 120-Hz Diode-Pumped Kilowatt Class Laser for Compton Scattering Sources

    NASA Astrophysics Data System (ADS)

    Bayramian, Andy; Beer, Glenn; Campbell, Rob; Freitas, Barry; Molander, William; Sutton, Steve; Telford, Steve; Barty, Chris

    2009-11-01

    A Mono-Energetic Gamma-Ray (MEGa-ray) Compton scattering light source is currently based on a 120-Hz electron accelerator. A 120-Hz laser source can increase the current gamma ray production by more than an order of magnitude and further enhancements are possible. Diode pumped solid state lasers (DPSSLs) offer the potential to operate at these higher repetition rates where flash lamp pumped laser systems are currently limited by thermal and lamp lifetime issues. Utilizing LLNL expertise in high energy DPSSLs, a 10-J, 120-Hz diode-pumped Nd:YAG laser architecture has been developed. The laser design makes use of advances in diode packaging, power conditioning, and beam conditioning to provide over 100-kW peak power array. Sapphire heatsinks and longitudinal cooling of the amplifier yields low parasitic loss and low wavefront distortion. An image relayed architecture and adaptive optics will yield a diffraction limited beam ideal for Compton scattering. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  10. Reliability of electric response audiometry using 80 Hz auditory steady-state responses.

    PubMed

    Kaf, Wafaa A; Sabo, Diane L; Durrant, John D; Rubinstein, Elaine

    2006-08-01

    The reliability of the Auditory Steady State Response (ASSR) has not been thoroughly evaluated despite its recent application as a clinical tool for threshold estimation. The purpose of this study was to examine test-retest (TR) reliability of ASSR threshold estimates in an empirical research design. The ASSR, tested using modulation frequencies approximately 80 Hz and above, was evaluated against pure tone audiometry (PTA), and the slow vertex potential (SVP, N1-P2). Sixteen normal-hearing young female adults were tested twice, one week apart. Varying degrees of sensorineural hearing loss of a notched configuration were simulated with filtered masking noise. Test-retest reliability was assessed using Pearson-product moment correlation analysis, supplemented by other post-hoc analyses. Results demonstrated moderately strong TR reliability for ASSR at 1000, 2000 and 4000 Hz (r = 0.83-0.93); however, the reliability of ASSR at 500 Hz was weaker (r = 0.75). Results suggest that ASSR-ERA is a reliable test at mid-high frequencies, at least with the configuration and degrees of simulated sensorineural hearing loss examined in this study.

  11. Investigation of effects of 60-Hz electric and magnetic fields on operant and social behavior and on the neuroendocrine system of nonhuman primates

    SciTech Connect

    Orr, J.L.

    1990-04-01

    The objective of this program is to investigate, using the baboon as a nonhuman primate surrogate for the human, behavioral and neuroendocrine effects associated with exposure to 60-Hz electric and magnetic fields. Results from this program, along with information from experiments conducted elsewhere, could be used to estimate and evaluate the likelihood of deleterious consequences resulting from exposure of humans to the electric and magnetic fields associated with electric power transmission. Activities this quarter extended those of the first project year: the modification of the facility to include 60-Hz magnetic fields, and development of the capability for studies of neuroendocrine parameters by obtaining blood samples from baboons during electric and magnetic field exposure. 18 figs., 7 tabs.

  12. Investigation of effects of 60-Hz electric and magnetic fields on operant and social behavior and on the neuroendocrine systems of nonhuman primates

    SciTech Connect

    Orr, J.L.

    1990-01-01

    The objective of this program is to investigate, using the baboon as a nonhuman primate surrogate for the human, behavioral and neuroendocrine effects associated with exposure to 60-Hz electric and magnetic fields. Results from this program, along with information from experiments conducted elsewhere, could be used to estimate and evaluate the likelihood of deleterious consequences resulting from exposure of humans to the electric and magnetic fields associated with electric power transmission. Activities this quarter extended those of the first project year which focused on two technical areas: the modification of the facility to include 60-Hz magnetic fields, and development of the capability for studies of neuroendocrine parameters by obtaining blood samples from baboons during electric and magnetic field exposure. 25 figs., 11 tabs.

  13. p53-independent apoptosis in UV-irradiated mouse skin: possible inhibition by 50 Hz magnetic fields.

    PubMed

    Kumlin, Timo; Heikkinen, Päivi; Kosma, Veli-Matti; Alhonen, Leena; Jänne, Juhani; Juutilainen, Jukka

    2002-06-01

    Our recent results suggest that 50 Hz magnetic fields (MF) enhance ultraviolet (UV)-induced tumorigenesis in mouse skin. The aim of the present experiment was to study suppression of apoptosis as a possible mechanism for MF effects on skin tumorigenesis. Another aim was to test the importance of a UV and MF exposure schedule, particularly the role of MF exposure prior to UV irradiation. Female mice were exposed to a UV dose of 2 human MED and to 100 microT MF of 50 Hz, using the following exposure schedules: group 1 sham MF 24 h, UV 1 h, sham MF 24 h; group 2 sham MF 24 h, UV 1 h, MF 24 h; group 3 MF 24 h, UV 1 h, MF 24 h. Lamps emitting simulated solar radiation (SSR) were used for UV irradiation. Skin samples were analysed for apoptosis, expression of the p53 gene, activity of the enzyme ornithine decarboxylase (ODC) and polyamine concentrations. A significantly (p = 0.017) lower number of apoptotic cells was measured in group 2 compared to group 1. A similar but not statistically significant (p = 0.064) decrease was also detected in group 3. No p53 expression was detected in any sample. The levels of ODC and putrescine did not differ significantly between the UV-only and UV and MF-exposed groups. Spermidine and spermine levels were significantly (p = 0.014 and 0.014, respectively) lower in group 3 than in group 1, but no decrease was observed in group 2. Our findings suggest that SSR induces p53-independent apoptosis in mouse skin and that the apoptotic response may be inhibited by exposure to MF. The exposure schedule did not alter the MF effect. The results do not support a causal role for polyamines in MF effects on apoptosis.

  14. Evaluation of the developmental toxicity of 60 Hz magnetic fields and harmonic frequencies in Sprague-Dawley rats.

    PubMed

    Ryan, B M; Polen, M; Gauger, J R; Mallett, E; Kearns, M B; Bryan, T L; McCormick, D L

    2000-05-01

    Experimental data suggest that exposure to the 50 and 60 Hz sinusoidal components of power-frequency magnetic fields (MFs) does not have an adverse impact on fetal development. However, the possible developmental toxicity of MF harmonics has not been investigated. This study was designed to determine whether exposure to 180 Hz MFs (third harmonic), alone or in combination with 60 Hz MFs, induces birth defects in Sprague-Dawley rats. Groups of sperm-positive dams (> or =20/group) were exposed for 18.5 h per day from gestation days 6 through 19 to (1) ambient MFs only (<0.0001 mT; sham controls); (2) 60 Hz MFs at 0.2 mT; (3) 180 Hz MFs at 0.2 mT; or (4) 60 Hz + 180 Hz MFs (10% third harmonic; total field strength = 0.2 mT). Litter size, litter weight, percentage live births, sex ratio, and number of resorption sites were determined for each dam, and gross external, visceral, cephalic and skeletal examinations were performed on all fetuses. MF exposure had no significant effects on litter size, litter weight, or fetal development. With the exception of common rib variants, the incidence of fetal anomalies was comparable in all groups. A small increase in the incidence of rib variants was seen in the group exposed to 60 Hz + 180 Hz MFs; however, the incidence of rib variants in this group was similar to that in historical controls from our laboratory. These data extend the existing database on developmental toxicity of MFs by demonstrating that exposure to 180 Hz MFs, either alone or superimposed on an underlying 60 Hz signal, does not induce biologically significant developmental toxicity. These data do not support the hypothesis that exposure to power-frequency MFs is an important risk factor for fetal development. PMID:10790286

  15. The strain in the array is mainly in the plane (waves below ~1 Hz)

    USGS Publications Warehouse

    Gomberg, J.; Pavlis, G.; Bodin, P.

    1999-01-01

    We compare geodetic and single-station methods of measuring dynamic deformations and characterize their causes in the frequency bands 0.5-1.0 Hz and 4.0-8.0 Hz. The geodetic approach utilizes data from small-aperture seismic arrays, applying techniques from geodesy. It requires relatively few assumptions and a priori information. The single-station method uses ground velocities recorded at isolated or single stations and assumes all the deformation is due to plane-wave propagation. It also requires knowledge of the azimuth and horizontal velocity of waves arriving at the recording station. Data employed come from a small-aperture, dense seismic array deployed in Geyokcha, Turkmenistan, and include seismograms recorded by broadband STS2 and short-period L28 sensors. Poor agreement between geodetic and single-station estimates in the 4.0-8.0 Hz passband indicates that the displacement field may vary nonlinearly with distance over distances of ~50 m. STS2 geodetic estimates provide a robust standard in the 0.5-1.0 Hz passband because they appear to be computationally stable and require fewer assumptions than single-station estimates. The agreement between STS2 geodetic estimates and single-station L28 estimates is surprisingly good for the S-wave and early surface waves, suggesting that the single-station analysis should be useful with commonly available data. These results indicate that, in the 0.5 to 1.0 Hz passband, the primary source of dynamic deformation is plane-wave propagation along great-circle source-receiver paths. For later arriving energy, the effects of scattering become important. The local structure beneath the array exerts a strong control on the geometry of the dynamic deformation, implying that it may be difficult to infer source characteristics of modern or paleoearthquakes from indicators of dynamic deformations. However, strong site control also suggests that the dynamic deformations may be predictable, which would be useful for engineering

  16. The topography of alpha-band activity tracks the content of spatial working memory.

    PubMed

    Foster, Joshua J; Sutterer, David W; Serences, John T; Vogel, Edward K; Awh, Edward

    2016-01-01

    Working memory (WM) is a system for the online storage of information. An emerging view is that neuronal oscillations coordinate the cellular assemblies that code the content of WM. In line with this view, previous work has demonstrated that oscillatory activity in the alpha band (8-12 Hz) plays a role in WM maintenance, but the exact contributions of this activity have remained unclear. Here, we used an inverted spatial encoding model in combination with electroencephalography (EEG) to test whether the topographic distribution of alpha-band activity tracks spatial representations held in WM. Participants in three experiments performed spatial WM tasks that required them to remember the precise angular location of a sample stimulus for 1,000-1,750 ms. Across all three experiments, we found that the topographic distribution of alpha-band activity tracked the specific location that was held in WM. Evoked (i.e., activity phase-locked to stimulus onset) and total (i.e., activity regardless of phase) power across a range of low-frequency bands transiently tracked the location of the sample stimulus following stimulus onset. However, only total power in the alpha band tracked the content of spatial WM throughout the memory delay period, which enabled reconstruction of location-selective channel tuning functions (CTFs). These findings demonstrate that alpha-band activity is directly related to the coding of spatial representations held in WM and provide a promising method for tracking the content of this online memory system.

  17. The topography of alpha-band activity tracks the content of spatial working memory.

    PubMed

    Foster, Joshua J; Sutterer, David W; Serences, John T; Vogel, Edward K; Awh, Edward

    2016-01-01

    Working memory (WM) is a system for the online storage of information. An emerging view is that neuronal oscillations coordinate the cellular assemblies that code the content of WM. In line with this view, previous work has demonstrated that oscillatory activity in the alpha band (8-12 Hz) plays a role in WM maintenance, but the exact contributions of this activity have remained unclear. Here, we used an inverted spatial encoding model in combination with electroencephalography (EEG) to test whether the topographic distribution of alpha-band activity tracks spatial representations held in WM. Participants in three experiments performed spatial WM tasks that required them to remember the precise angular location of a sample stimulus for 1,000-1,750 ms. Across all three experiments, we found that the topographic distribution of alpha-band activity tracked the specific location that was held in WM. Evoked (i.e., activity phase-locked to stimulus onset) and total (i.e., activity regardless of phase) power across a range of low-frequency bands transiently tracked the location of the sample stimulus following stimulus onset. However, only total power in the alpha band tracked the content of spatial WM throughout the memory delay period, which enabled reconstruction of location-selective channel tuning functions (CTFs). These findings demonstrate that alpha-band activity is directly related to the coding of spatial representations held in WM and provide a promising method for tracking the content of this online memory system. PMID:26467522

  18. Saccades during visual exploration align hippocampal 3–8 Hz rhythms in human and non-human primates

    PubMed Central

    Hoffman, Kari L.; Dragan, Michelle C.; Leonard, Timothy K.; Micheli, Cristiano; Montefusco-Siegmund, Rodrigo; Valiante, Taufik A.

    2013-01-01

    Visual exploration in primates depends on saccadic eye movements (SEMs) that cause alternations of neural suppression and enhancement. This modulation extends beyond retinotopic areas, and is thought to facilitate perception; yet saccades may also influence brain regions critical for forming memories of these exploratory episodes. The hippocampus, for example, shows oscillatory activity that is generally associated with encoding of information. Whether or how hippocampal oscillations are influenced by eye movements is unknown. We recorded the neural activity in the human and macaque hippocampus during visual scene search. Across species, SEMs were associated with a time-limited alignment of a low-frequency (3–8 Hz) rhythm. The phase alignment depended on the task and not only on eye movements per se, and the frequency band was not a direct consequence of saccade rate. Hippocampal theta-frequency oscillations are produced by other mammals during repetitive exploratory behaviors, including whisking, sniffing, echolocation, and locomotion. The present results may reflect a similar yet distinct primate homologue supporting active perception during exploration. PMID:24009562

  19. PULSE AMPLITUDE DEPENDS ON kHz QPO FREQUENCY IN THE ACCRETING MILLISECOND PULSAR SAX J1808.4-3658

    SciTech Connect

    Bult, Peter; Van der Klis, Michiel

    2015-01-10

    We study the relation between the 300-700 Hz upper kHz quasi-periodic oscillation (QPO) and the 401 Hz coherent pulsations across all outbursts of the accreting millisecond X-ray pulsar SAX J1808.4-3658 observed with the Rossi X-ray Timing Explorer. We find that the pulse amplitude systematically changes by a factor of ∼2 when the upper kHz QPO frequency passes through 401 Hz: it halves when the QPO moves to above the spin frequency and doubles again on the way back. This establishes for the first time the existence of a direct effect of kHz QPOs on the millisecond pulsations and provides a new clue to the origin of the upper kHz QPO. We discuss several scenarios and conclude that while more complex explanations can not formally be excluded, our result strongly suggests that the QPO is produced by azimuthal motion at the inner edge of the accretion disk, most likely orbital motion. Depending on whether this azimuthal motion is faster or slower than the spin, the plasma then interacts differently with the neutron-star magnetic field. The most straightforward interpretation involves magnetospheric centrifugal inhibition of the accretion flow that sets in when the upper kHz QPO becomes slower than the spin.

  20. Towards a reference ultrasonic cavitation vessel. Part 1: preliminary investigation of the acoustic field distribution in a 25 kHz cylindrical cell.

    PubMed

    Hodnett, Mark; Choi, Min Joo; Zeqiri, Bajram

    2007-01-01

    The acoustic field produced by a 25 kHz, 25 l cylindrical sonochemical processing cell has been characterised systematically using a sonar hydrophone, with the aim of establishing it as a reference test bed on which future investigations into acoustic cavitation activity may be based. Data acquired at sonication levels up to 500 W have shown that though significant cavitation activity is generated throughout the vessel, the acoustic field generated is reproducible, typically to +/- 12%. The increases in acoustic pressure are shown to be nonlinear with applied power, suggesting an intermediate optimum level for future study.

  1. Clinical significance of neuropsychological improvement after supplementation with omega-3 in 8-12 years old malnourished Mexican children: a randomized, double-blind, placebo and treatment clinical trial.

    PubMed

    Portillo-Reyes, Verónica; Pérez-García, Miguel; Loya-Méndez, Yolanda; Puente, Antonio E

    2014-04-01

    It has been shown that supplementation with omega-3 improves cognitive performance, especially in infants and toddlers, but it is unknown whether these results are effective in older malnourished children. The aims of this study, therefore, were to investigate the omega-3 supplementation effects in 8- to 12-year-old children and to know which neuropsychological functions improve after three months of intervention in a sample of Mexican children with mild to moderate malnutrition. This study was a randomized, double-blind, treatment and placebo study of 59 children aged 8-12 years who were individually allocated to 2 groups. The duration of the intervention lasted 3 months. Neuropsychological performance was measured at baseline and at 3 months. Results show that more than 50% of children in the treatment group had greater improvement in 11 of the 18 neuropsychological variables studied. Processing speed, visual-motor coordination, perceptual integration, attention and executive function showed improvement in more than 70% of the omega-3 supplemented children. This trial was registered at clinicaltrials.gov as NCT01199120. PMID:24508294

  2. Active rejector filter

    SciTech Connect

    Kuchinskii, A.G.; Pirogov, S.G.; Savchenko, V.M.; Yakushev, A.K.

    1985-01-01

    This paper describes an active rejector filter for suppressing noise signals in the frequency range 50-100 Hz and for extracting a vlf information signal. The filter has the following characteristics: a high input impedance, a resonant frequency of 75 Hz, a Q of 1.25, and an attenuation factor of 53 dB at resonant frequency.

  3. Rodent ultrasonic communication: Male prosocial 50-kHz ultrasonic vocalizations elicit social approach behavior in female rats (Rattus norvegicus).

    PubMed

    Willadsen, Maria; Seffer, Dominik; Schwarting, Rainer K W; Wöhr, Markus

    2014-02-01

    Rats emit distinct types of ultrasonic vocalizations (USV), which serve as situation-dependent affective signals with important communicative functions. Low-frequency 22-kHz USV typically occur in aversive situations, such as social defeat, whereas high-frequency 50-kHz USV can be observed in appetitive situations, like rough-and-tumble-play in juveniles or mating in adults. The 2 main USV types serve distinct communicative functions and induce call-specific behavioral responses in the receiver. While 22-kHz USV probably serve as alarm calls, 50-kHz USV appear to serve a prosocial communicative function in the sexual and the nonsexual context. In the sexual context, however, this view has recently been challenged by playback studies where only very limited behavioral changes were observed in response to prosocial 50-kHz USV. The aim of the present study was therefore to test whether female rats display social approach behavior in response to male prosocial 50-kHz USV by means of our established playback paradigm. To this aim, we exposed female rats to playback of the following 2 acoustic stimuli: (a) natural male 50-kHz USV and (b) time- and amplitude-matched white noise, with the latter serving as acoustic control for novelty-induced changes in behavior not linked to the communicative function of male prosocial 50-kHz USV. Our present findings show that female rats display high levels of social approach behavior in response to male prosocial 50-kHz USV, but not time- and amplitude-matched white noise, supporting the conclusion that male prosocial 50-kHz USV are likely to play an important role in establishing social proximity and possibly regulate mating behavior.

  4. Camera-based three-dimensional real-time particle tracking at kHz rates and Ångström accuracy

    PubMed Central

    Daldrop, Peter; Joo, Sihwa; Otto, Oliver; Keyser, Ulrich F.; Seidel, Ralf

    2014-01-01

    Optical and magnetic tweezers are widely employed to probe the mechanics and activity of individual biomolecular complexes. They rely on micrometer-sized particles to detect molecular conformational changes from the particle position. Real-time particle tracking with Ångström accuracy has so far been only achieved using laser detection through photodiodes. Here we demonstrate that camera-based imaging can provide a similar performance for all three dimensions. Particle imaging at kHz rates is combined with real-time data processing being accelerated by a graphics processing unit. For particles that are fixed in the sample cell we can detect 3 Å sized steps that are introduced by cell translations at rates of 10 Hz, while for DNA-tethered particles 5 Å steps at 1 Hz can be resolved. Moreover, 20 particles can be tracked in parallel with comparable accuracy. Our approach provides a simple and robust way for high-resolution tweezers experiments using multiple particles at a time. PMID:25565216

  5. Testing the interaction between dark energy and dark matter with H(z) data

    NASA Astrophysics Data System (ADS)

    Yu, Pan; Li, Li; Shuo, Cao; Na-na, Pan; Yi, Zhang; Zi-xuan, Hu

    2016-04-01

    With the Markov Chain Monte Carlo (MCMC) method, we constrain an interactive dark energy model by combing the up-to-date observational data of Hubble parameter H(z) with the 7-year baryon acoustic oscillation (BAO) data, and the cosmic microwave background (CMB) data observed by the Planck satellite. Under the joint constraint of the three kinds of data, the best-fit values of the model parameters and their 1-σ errors are obtained as follows: the energy density Ωm =0.266-0.028+0.028 (1 σ) , the interaction factor γ =0.090-0.098+0.100 (1 σ) , the parameter of state equation of dark matter wX = -1.307-0.269+0.263 (1 σ) , and the Hubble Constant H0 =7420-4.56+4.66 (1 σ) , where the coupling parameter γ > 0 means that the energy is transferred from dark matter to dark energy, and the coincidence problem in the Lambda-Cold Dark Matter (ΛCDM) model is slightly alleviated in the 1σ range. For comparisons, we constrain the same model with the BAO+CMB observations and H(z) data separately. The results are as follows: (1) The H(z) data could put stricter constraint on the parameter γ than the BAO+CMB observations. (2) The ΛCDM model is best fitted, and the coupling parameter γ is correlated with parameters Ωm and H0. (3) The inconsistency of the constraint results of H0 between the local distance ladder measurements and the Planck observations can be alleviated after taking account of the interaction between dark energy and dark matter.

  6. 40-Hz oscillations underlying perceptual binding in young and older adults.

    PubMed

    Ross, Bernhard; Fujioka, Takako

    2016-07-01

    Auditory object perception requires binding of elementary features of complex stimuli. Synchronization of high-frequency oscillation in neural networks has been proposed as an effective alternative to binding via hard-wired connections because binding in an oscillatory network can be dynamically adjusted to the ever-changing sensory environment. Previously, we demonstrated in young adults that gamma oscillations are critical for sensory integration and found that they were affected by concurrent noise. Here, we aimed to support the hypothesis that stimulus evoked auditory 40-Hz responses are a component of thalamocortical gamma oscillations and examined whether this oscillatory system may become less effective in aging. In young and older adults, we recorded neuromagnetic 40-Hz oscillations, elicited by monaural amplitude-modulated sound. Comparing responses in quiet and under contralateral masking with multitalker babble noise revealed two functionally distinct components of auditory 40-Hz responses. The first component followed changes in the auditory input with high fidelity and was of similar amplitude in young and older adults. The second, significantly smaller in older adults, showed a 200-ms interval of amplitude and phase rebound and was strongly attenuated by contralateral noise. The amplitude of the second component was correlated with behavioral speech-in-noise performance. Concurrent noise also reduced the P2 wave of auditory evoked responses at 200-ms latency, but not the earlier N1 wave. P2 modulation was reduced in older adults. The results support the model of sensory binding through thalamocortical gamma oscillations. Limitation of neural resources for this process in older adults may contribute to their speech-in-noise understanding deficits. PMID:27080577

  7. Large-aperture, tapered fiber-coupled, 10-kHz particle-image velocimetry.

    PubMed

    Hsu, Paul S; Roy, Sukesh; Jiang, Naibo; Gord, James R

    2013-02-11

    We demonstrate the design and implementation of a fiber-optic beam-delivery system using a large-aperture, tapered step-index fiber for high-speed particle-image velocimetry (PIV) in turbulent combustion flows. The tapered fiber in conjunction with a diffractive-optical-element (DOE) fiber-optic coupler significantly increases the damage threshold of the fiber, enabling fiber-optic beam delivery of sufficient nanosecond, 532-nm, laser pulse energy for high-speed PIV measurements. The fiber successfully transmits 1-kHz and 10-kHz laser pulses with energies of 5.3 mJ and 2 mJ, respectively, for more than 25 min without any indication of damage. It is experimentally demonstrated that the tapered fiber possesses the high coupling efficiency (~80%) and moderate beam quality for PIV. Additionally, the nearly uniform output-beam profile exiting the fiber is ideal for PIV applications. Comparative PIV measurements are made using a conventionally (bulk-optic) delivered light sheet, and a similar order of measurement accuracy is obtained with and without fiber coupling. Effective use of fiber-coupled, 10-kHz PIV is demonstrated for instantaneous 2D velocity-field measurements in turbulent reacting flows. Proof-of-concept measurements show significant promise for the performance of fiber-coupled, high-speed PIV using a tapered optical fiber in harsh laser-diagnostic environments such as those encountered in gas-turbine test beds and the cylinder of a combustion engine. PMID:23481818

  8. On the Solar Origin of the 220.7 μHz Signal

    NASA Astrophysics Data System (ADS)

    Jiménez, A.; García, R. A.

    2009-12-01

    Gravity modes in the Sun have been long searched for during the past decades. Using their asymptotic properties García et al. (2007) found the signature of the dipole g modes analyzing an spectral window between 25 and 140 μHz of velocity power spectrum obtained from the Global Oscillations at Low Frequencies (GOLF)/SoHO instrument. Using this result it has been possible to check some properties of the structure of the solar interior (García, Mathur & Ballot 2008) as well as some indications of the dynamics of the core. However, the individual detection of such modes remains evasive and they are needed to really improve our knowledge of the deepest layers in the Sun (Mathur et al. 2008). In this work we study the signal at 220.7 μHz which is present in most of the helioseismic instruments during the last 10 years. This signal has been previously identified as part of a g-mode candidate in the GOLF data (Turck-Chièze et al. 2004; Mathur et al. 2007) and in SPM/Variability of solar IRradiance and Gravity Oscillations (VIRGO) (García et al. 2008) with more than 90% confidence level. It could be labeled as the l=2 n=-3 g mode as it is in the region were this mode is expected. We have checked the possibility that the 220.7 μHz signal could have an instrumental origin without success by analyzing all available housekeeping data as well as information on the roll, pitch and yaw of the SoHO spacecraft. In consequence, we are confident that this signal has a solar origin.

  9. Large-aperture, tapered fiber-coupled, 10-kHz particle-image velocimetry.

    PubMed

    Hsu, Paul S; Roy, Sukesh; Jiang, Naibo; Gord, James R

    2013-02-11

    We demonstrate the design and implementation of a fiber-optic beam-delivery system using a large-aperture, tapered step-index fiber for high-speed particle-image velocimetry (PIV) in turbulent combustion flows. The tapered fiber in conjunction with a diffractive-optical-element (DOE) fiber-optic coupler significantly increases the damage threshold of the fiber, enabling fiber-optic beam delivery of sufficient nanosecond, 532-nm, laser pulse energy for high-speed PIV measurements. The fiber successfully transmits 1-kHz and 10-kHz laser pulses with energies of 5.3 mJ and 2 mJ, respectively, for more than 25 min without any indication of damage. It is experimentally demonstrated that the tapered fiber possesses the high coupling efficiency (~80%) and moderate beam quality for PIV. Additionally, the nearly uniform output-beam profile exiting the fiber is ideal for PIV applications. Comparative PIV measurements are made using a conventionally (bulk-optic) delivered light sheet, and a similar order of measurement accuracy is obtained with and without fiber coupling. Effective use of fiber-coupled, 10-kHz PIV is demonstrated for instantaneous 2D velocity-field measurements in turbulent reacting flows. Proof-of-concept measurements show significant promise for the performance of fiber-coupled, high-speed PIV using a tapered optical fiber in harsh laser-diagnostic environments such as those encountered in gas-turbine test beds and the cylinder of a combustion engine.

  10. A four kHz repetition rate compact TEA CO2 laser

    NASA Astrophysics Data System (ADS)

    Zheng, Yijun; Tan, Rongqing

    2013-09-01

    A compact transversely excited atmospheric (TEA) CO2 laser with high repetition-rate was reported. The size of the laser is 380 mm×300 mm×200 mm, and the discharge volume is 12×103 mm3. The laser cavity has a length of 320mm and consists of a totally reflective concave mirror with a radius of curvature of 4 m (Cu metal substrate coated with Au) and a partially reflecting mirror. The ultraviolet preionization makes the discharge even and stable,the output energy can be as high as 28 mJ under the circumstance of free oscillation, and the width of the light pulse is 60ns.To acquire the high wind velocity, a turbocharger is used in the system of the fast-gas flow cycle. When the wind speed is 100m/s, the repetition rate of the transversely excited atmospheric CO2 laser is up to 2 kHz. On this basis, a dual modular structure with two sets of the gas discharge unit is adopted to obtain a higher pulse repetition frequency output. The dual discharge unit composed two sets of electrodes and two sets of turbo fan. Alternate trigger technology is used to make the two sets of discharge module work in turn with repetition frequency of 2 kHz, the discharge interval of two sets of the gas discharge unit can be adjusted continuously from 20 microseconds to 250 microseconds. Under the conditions of maintaining the other parameters constant, the repetition frequency of the laser pulse is up to 4 kHz. The total size of laser with dual modular structure is 380mm×520mm×200mm, and the discharge volume is 24×103 mm3 with the cavity length of 520mm.

  11. Ground-truthing 6. 5-kHz side scan sonographs: What are we really imaging

    SciTech Connect

    Gardner, J.V.; Field, M.E.; Lee, H.; Edwards, B.E. ); Masson, D.G.; Kenyon, N. ); Kidd, R.B. )

    1991-04-10

    A 1,000-km{sup 2} area on the distal lobe of Monterey Fan shows a digitate pattern of juxtaposed high and low backscatter on GLORIA side scan sonographs. This area was investigated using stereo photography, high-resolution seismic profiles, and measurements of physical properties of cores to quantitatively evaluate the causes of backscatter from the 6.5-kHz side scan sonar. Stereo photography and bottom video were used to determine that the sediment-water interface typically has a bed roughness less than 10 cm over the entire ground truth area; consequently, bed roughness is not a significant contributor to the sonar backscatter. Vertical-incidence 3.5-kHz profiles reveal that high-backscatter areas allow less penetration and have slightly more relief than low-backscatter areas. Closely spaced measurements of {rho} wave velocity, density, and grain size made on transponder-navigated cores are used to investigate the geoacoustic properties of the sediment with the aid of a numerical model. The model results demonstrate that the sediment-water interface is, in most cases, acoustically transparent to the sonar energy and that most or all of the energy is refracted into the sediment to depths of at least a few meters rather than scattered from the surface. In this area, thick (up to 50 cm) sand deposits with thin interbeds of silty clay correlate with lower backscatter than do silty clay deposits with thin interbeds of sand. This suggests that volume inhomogeneities and complex constructive and destructive interferences caused by the subsurface volume inhomogeneities within the top few meters of the sediment ultimately modulate the intensity of backscatter. Although 6.5-kHz sonographs appear easy to interpret in a conventional and simplistic manner, caution should be used when interpreting lithofacies from backscatter intensities.

  12. Beyond Quasi-Geostrophic Turbulence: Generalized Scale Invariance and (2+Hz)-Dimensional Vorticity Equations

    NASA Astrophysics Data System (ADS)

    Schertzer, D. J.; Tchiguirinskaia, I.; Lovejoy, S.; Tuck, A.

    2010-12-01

    We discuss the claim of Lindborg et al (2009) that the spectrum power law E(k)≈k-3 on scales ≥600 km obtained with the help of commercial jetliner trajectory deviations (GASP and Mozaic databases) could not be brought into question by Lovejoy et al (2009), because this spectrum corresponds to a “well known theory of quasi-geostrophic turbulence developed by Charney (1971)”. Lindborg, et al (2009) also argued that “earlier limitations [of this theory] would have been relaxed in many of the modern models of atmospheric turbulence”. We show that both these statements are irrelevant and that generalized scale invariance (GSI, Schertzer and Lovejoy 1985) is rather indispensable to go beyond the quasi-geostrophic limitations, to go in fact from scale analysis to scaling analysis. This enables us to derive dynamical equations for the vorticity in an embedding space of (fractional) dimension D=2+Hz (0≤ Hz ≤1, 1- Hz measures the scaling stratification of atmospheric turbulence). These equations correspond to an interesting dynamical alternative to quasi-geostrophic approximation and turbulence. References: Charney, J. G. (1971). "Geostrophic Turbulence." J. Atmos. Sci 28: 1087. Lindborg, E., K. K. Tung, G. D. Nastrom, J. Y. N. Cho and K. S. Gage (2009). "Comment on "Reinterpreting aircraft measurements in anisotropic scaling turbulence" by lovejoy et al. (2009)." Atmos. Chem. Phys. Discuss. 9: 22331-22336. Lovejoy, S., A. F. Tuck, D. Schertzer and S. J. Hovde (2009). "Rinterpreting aircraft measurements in anisotropic scaling turbulence." Atmos. Chem. Phys. 9: 5007-5025. Schertzer, D. and S. Lovejoy (1985). "Generalised scale invariance in turbulent phenomena." Physico-Chemical Hydrodynamics Journal 6: 623-635.

  13. Evaluation of potential health effects of 10 kHz magnetic fields: a rodent reproductive study.

    PubMed

    Dawson, B V; Robertson, I G; Wilson, W R; Zwi, L J; Boys, J T; Green, A W

    1998-01-01

    New technology involving the use of high-frequency inductive power distribution (HID) has recently been developed for use in materials handling and personnel transfer. Sinusoidal magnetic fields at a frequency of 10 kHz with field intensities of approximately 0.2 mT are generated directly between the current-carrying coils of this equipment. Effects of 10 kHz magnetic fields on cell division, migration, and differentiation have never been previously investigated. To evaluate potential effects on these parameters, a rodent reproductive study was undertaken using Wistar rats. Exposures were at 0.095, 0.24, and 0.95 mT with a background exposure of 5-10 microT. Three sets of parental rats were exposed continuously for 20-23.5 h/day to the fields: maternal rats during gestation, paternal rats for at least 45 days prior to mating and maternal rats 1 month prior to mating. Exposure phases thus covered spermatogenesis, maturation of the ovum and ovulation, fertilization, implantation, embryogenesis, organogenesis, and maturation of the fetus immediately prior to parturition. In all experiments pregnancy outcome was assessed. These studies failed to demonstrate any reproductive toxicity resulting from maternal or fetal exposure during gestation or following paternal or maternal exposure for several weeks prior to mating. No quantitative or qualitative effects on spermatogenesis occurred after exposure, and no effects on the estrous cycle or ovulation could be demonstrably linked to the 10 kHz magnetic field exposure at 0.095, 0.25, or 0.95 mT. Where possible, parental clinical chemistry and hematology were also examined. As in mouse toxicology studies previously reported, minor differences were observed between control and treated groups. These were regarded as statistically, but not biologically, significant and could not categorically be attributed to magnetic field exposure.

  14. Bulk Current Injection Testing of Cable Noise Reduction Techniques, 50 kHz to 400 MHz

    NASA Technical Reports Server (NTRS)

    Bradley, Arthur T.; Hare, Richard J.; Singh, Manisha

    2009-01-01

    This paper presents empirical results of cable noise reduction techniques as demonstrated using bulk current injection (BCI) techniques with radiated fields from 50 kHz - 400 MHz. It is a follow up to the two-part paper series presented at the Asia Pacific EMC Conference that focused on TEM cell signal injection. This paper discusses the effects of cable types, shield connections, and chassis connections on cable noise. For each topic, well established theories are compared with data from a real-world physical system.

  15. Upgrading a high-throughput spectrometer for high-frequency (<400 kHz) measurements

    NASA Astrophysics Data System (ADS)

    Nishizawa, T.; Nornberg, M. D.; Den Hartog, D. J.; Craig, D.

    2016-11-01

    The upgraded spectrometer used for charge exchange recombination spectroscopy on the Madison Symmetric Torus resolves emission fluctuations up to 400 kHz. The transimpedance amplifier's cutoff frequency was increased based upon simulations comparing the change in the measured photon counts for time-dynamic signals. We modeled each signal-processing stage of the diagnostic and scanned the filtering frequency to quantify the uncertainty in the photon counting rate. This modeling showed that uncertainties can be calculated based on assuming each amplification stage is a Poisson process and by calibrating the photon counting rate with a DC light source to address additional variation.

  16. Buffer-gas-induced linewidth reduction of coherent dark resonances to below 50 Hz

    NASA Astrophysics Data System (ADS)

    Brandt, S.; Nagel, A.; Wynands, R.; Meschede, D.

    1997-08-01

    When neon is introduced as a buffer gas the interaction time of cesium atoms in a vapor cell with resonant laser beams is drastically increased. Using a pair of phase-locked lasers we have observed linewidths as narrow as 42 Hz for coherent dark resonances in a cesium vapor cell. We study the influence of power and pressure broadening and systematic shifts of the resonance frequency. Our experiments demonstrate that coherent dark resonances could rival direct radio-frequency precision measurements, which have a wide range of applications in physics.

  17. A Technique for Estimating the Occlusion Effect for Frequencies Below 125 Hz

    PubMed Central

    Stone, Michael A.; Paul, Anna M.; Axon, Patrick; Moore, Brian C.J.

    2014-01-01

    Objectives The level of bone-conducted sound in the auditory meatus is increased at low frequencies by occlusion of the meatus, for example by the earmold of a hearing aid. Physical measures of this “occlusion effect” (OE) require vibration of the skull. In previous research, either self-voicing or audiometric bone-conduction vibrators have been used to produce this vibration, with the result that the OE could not be measured for frequencies below 125 Hz. However, frequencies below this can be important for music perception by hearing aid users. The objective was to develop and evaluate a method that gives a lower-bound estimate of the OE for frequencies below 125 Hz. Design A low-noise amplifier with extended low-frequency response was used to record the output of a miniature microphone inserted into the meatus of participants. The signal came from sounds of the heartbeat and blood flow of the participant, transmitted via bone-conduction through the walls of the meatus. A simultaneous recording was made of the carotid pulse to permit time-locked averaging (and hence noise reduction) of the microphone signal. Recordings were made from seven otologically and audiometrically normal participants, using clinical probe tips to produce the occlusion. Recordings were also made from an overlapping group of nine participants, using fast-setting impression material to provide a more consistent degree of occlusion. The difference in level of the recorded signal for unoccluded and occluded conditions provided a lower bound for the magnitude of the OE. Results The mean OE increased with decreasing frequency, reaching a plateau of about 40 dB for frequencies below 40 Hz. For some individual recordings, the OE reached 50 dB for frequencies below 20 Hz. With occlusion, the heartbeat became audible for most participants. Conclusions The OE can be very large at low frequencies. The use of hearing aids with closed fittings, which may be employed either to prevent acoustic

  18. High-order harmonic generation at a repetition rate of 100 kHz

    SciTech Connect

    Lindner, F.; Stremme, W.; Schaetzel, M. G.; Grasbon, F.; Paulus, G. G.; Walther, H.; Hartmann, R.; Strueder, L.

    2003-07-01

    We report high-order harmonic generation (HHG) in rare gases using a femtosecond laser system with a very high repetition rate (100 kHz) and low pulse energy (7 {mu}J). To our knowledge, this is the highest repetition rate reported to date for HHG. The tight focusing geometry required to reach sufficiently high intensities implies low efficiency of the process. Harmonics up to the 45th order are nevertheless generated and detected. We show evidence of clear separation and selection of quantum trajectories by moving the gas jet with respect to the focus, in agreement with the theoretical predictions of the semiclassical model of HHG.

  19. New physics and signal-background interference in associated pp → HZ production

    NASA Astrophysics Data System (ADS)

    Englert, Christoph; Rosenfeld, Rogerio; Spannowsky, Michael; Tonero, Alberto

    2016-05-01

    We re-investigate electroweak signal-background interference in associated Higgs production via gluon fusion in the presence of new physics in the top Higgs sector. Considering the full final state pp \\to b \\bar b \\ell^+\\ell^-~(\\ell=e,μ) , we discuss how new physics in the top Higgs sector that enhances the ZZ component can leave footprints in the HZ limit setting. In passing we investigate the phenomenology of a class of new physics interactions that can be genuinely studied in this process.

  20. The phonological function of vowels is maintained at fundamental frequencies up to 880 Hz.

    PubMed

    Friedrichs, Daniel; Maurer, Dieter; Dellwo, Volker

    2015-07-01

    In a between-subject perception task, listeners either identified full words or vowels isolated from these words at F0s between 220 and 880 Hz. They received two written words as response options (minimal pair with the stimulus vowel in contrastive position). Listeners' sensitivity (A') was extremely high in both conditions at all F0s, showing that the phonological function of vowels can also be maintained at high F0s. This indicates that vowel sounds may carry strong acoustic cues departing from common formant frequencies at high F0s and that listeners do not rely on consonantal context phenomena for their identification performance. PMID:26233058

  1. Wavelength tunable, 264 J laser diode array for 10 Hz/1ms Yb:YAG pumping

    NASA Astrophysics Data System (ADS)

    Chanteloup, J.-C.; Albach, D.; Assémat, F.; Bahbah, S.; Bourdet, G.; Piatti, P.; Pluvinage, M.; Vincent, B.; LeTouzé, G.; Mattern, T.; Biesenbach, J.; Müntz, H.; Noeske, A.; Venohr, R.

    2008-05-01

    The Lucia [1,2] Laser program, under development at the LULI laboratory, aims at delivering a 1030 nm, 100J, 10 Hz, 10 ns pulse train. The two laser heads used in the amplification stage relies on water-cooled mm-thick Yb:YAG disks, each of them pumped by a 34×13 cm2 Laser Diode Array (LDA). For each LDA, the 88 QCW diodes stacks manufactured by DILAS GmbH will be tiled in an 8×11 arrangement. Fine wavelength tuning is performed through bias current adjustment, water temperature control and conductivity adjustment. Wavelength homogeneity experimental verification has been validated.

  2. Calibration of miniature medical ultrasonic hydrophones for frequencies in the range 100 to 500 kHz using an ultrasonically absorbing waveguide.

    PubMed

    Rajagopal, Srinath; Zeqiri, Bajram; Gélat, Pierre N

    2014-05-01

    Enhancements to the existing primary standard optical interferometer and narrowband tone-burst comparison calibration methods for miniature medical ultrasonic hydrophones of the membrane type over the frequency range 100 to 500 kHz are described. Improvements were realized through application of an ultrasonically absorbing waveguide made of a low-frequency-absorbing tile used in sonar applications which narrows the spatial extent of the broad acoustic field. The waveguide was employed in conjunction with a sonar multilayered polyvinylidene difluoride (PVDF) hydrophone used as a transmitting transducer covering a frequency range of 100 kHz to 1 MHz. The acoustic field emanating from the ultrasonically absorbing waveguide reduced the significance of diffracted acoustic waves from the membrane hydrophone ring and the consequent interference of this wave with the direct acoustic wave received by the active element of the hydrophone during calibration. Four membrane hydrophone make/ models with ring sizes (defined as the inner diameter of the annular mounting ring of the hydrophone) in the range 50 to 100 mm were employed along with a needle hydrophone. A reference membrane hydrophone, calibrated using the NPL primary standard optical interferometer in combination with the ultrasonically absorbing waveguide, was subsequently used to calibrate the other four hydrophones by comparison, again using the ultrasonically absorbing waveguide. In comparison to existing methods, the use of the ultrasonically absorbing waveguide enabled the low-frequency calibration limit of a membrane hydrophone with a ring diameter of 50 mm to be reduced from 400 kHz to 200 kHz.

  3. XMM-Newton discovery of mHz quasi-periodic oscillations in the high-mass X-ray binary IGR J19140+0951

    NASA Astrophysics Data System (ADS)

    Sidoli, L.; Esposito, P.; Motta, S. E.; Israel, G. L.; Rodríguez Castillo, G. A.

    2016-08-01

    We report on the discovery of mHz quasi-periodic oscillations (QPOs) from the high-mass X-ray binary (HMXB) IGR J19140+0951, during a 40 ks XMM-Newton observation performed in 2015, which caught the source in its faintest state ever observed. At the start of the observation, IGR J19140+0951 was at a low flux of 2 × 10-12 erg cm-2 s-1 (2-10 keV; LX = 3 × 1033 erg s-1 at 3.6 kpc), then its emission rose reaching a flux ˜10 times higher, in a flare-like activity. The investigation of the power spectrum reveals the presence of QPOs, detected only in the second part of the observation, with a strong peak at a frequency of 1.46 ± 0.07 mHz, together with higher harmonics. The X-ray spectrum is highly absorbed (NH = 1023 cm-2), well fitted by a power law with a photon index in the range 1.2-1.8. The re-analysis of a Chandra archival observation shows a modulation at ˜0.17 ± 0.05 mHz, very likely the neutron-star spin period (although a QPO cannot be excluded). We discuss the origin of the 1.46 mHz QPO in the framework of both disc-fed and wind-fed HMXBs, favouring the quasi-spherical accretion scenario. The low flux observed by XMM-Newton leads to about three orders of magnitude the source dynamic range, overlapping with the one observed from Supergiant Fast X-ray Transients (SFXTs). However, since its duty cycle is not as low as in SFXTs, IGR J19140+0951 is an intermediate system between persistent supergiant HMXBs and SFXTs, suggesting a smooth transition between these two sub-classes.

  4. A continent-wide map of 1-Hz Lg coda Q variation across Eurasia and its relation to lithospheric evolution

    NASA Astrophysics Data System (ADS)

    Mitchell, Brian J.; Cong, Lianli; EkströM, Goran

    2008-04-01

    We present new maps of Lg coda Q (Qo and its frequency dependence) at 1-Hz that cover virtually all of Eurasia. Qo is relatively high, up to 650 or more, in the east European, Siberian, Indian, and Kazakh platforms but is surprisingly low (300-500) in the Arabian platform and western portion of the Siberian platform as well as in Great Britain and the northwestern portion of mainland Europe. It is generally low throughout the Tethysides orogenic belt, but there too it displays substantial regional variations (150-400). Most Qo anomalies appear to be related to the tectonic history of the Eurasian crust. The four regions with lowest values coincide with four of Eurasia's most active concentrations of earthquake activity. Observed Eurasian Qo values are consistent with a previously determined empirical plot of global values in which Qo in any region is proportional to the time elapsed since the most recent episode of tectonic or orogenic activity there. Comparisons of the new Qo map with maps of Rayleigh wave velocity, temperature, subducted lithosphere, and seismicity lead us to infer that Lg coda wave attenuation is most easily explained by energy lost in moving fluids through permeable rock or in being scattered from fluid-enhanced zones. The fluids are likely to have originated by hydrothermal release from subducting lithosphere or other upper mantle heat sources. Anomalies in Qo and other lithospheric properties in some cases extend well outside the Tethysides belt and other regions where upper mantle heat sources are known to occur. Possible explanations include earlier episodes of subduction activity, crustal deformation due to collision of the Afro-Arabian and Indian plates, or broader than expected back-arc activity beneath Eurasia.

  5. Effect of infrasound on cochlear damage from exposure to a 4-kHz octave band of noise

    PubMed Central

    Harding, Gary W.; Bohne, Barbara A.; Lee, Steve C.; Salt, Alec N.

    2008-01-01

    Infrasound (i.e., < 20 Hz for humans; < 100 Hz for chinchillas) is not audible, but exposure to high levels of infrasound will produce large movements of cochlear fluids. We speculated that high-level infrasound might bias the basilar membrane and perhaps be able to minimize noise-induced hearing loss. Chinchillas were simultaneously exposed to a 30 Hz tone at 100 dB SPL and a 4-kHz OBN at either 108 dB SPL for 1.75 h or 86 dB SPL for 24 h. For each animal, the tympanic membrane (TM) in one ear was perforated (~1 mm2) prior to exposure to attenuate infrasound transmission to that cochlea by about 50 dB SPL. Controls included animals that were exposed to the infrasound only or the 4-kHz OBN only. ABR threshold shifts (TSs) and DPOAE level shifts (LSs) were determined pre- and post-TM-perforation and immediately post-exposure, just before cochlear fixation. The cochleae were dehydrated, embedded in plastic, and dissected into flat preparations of the organ of Corti (OC). Each dissected segment was evaluated for losses of inner hair cells (IHCs) and outer hair cells (OHCs). For each chinchilla, the magnitude and pattern of functional and hair cell losses were compared between their right and left cochleae. The TM perforation produced no ABR TS across frequency but did produce a 10–21 dB DPOAE LS from 0.6–2 kHz. The infrasound exposure alone resulted in a 10–20 dB ABR TS at and below 2 kHz, no DPOAE LS and no IHC or OHC losses. Exposure to the 4-kHz OBN alone at 108 dB produced a 10–50 dB ABR TS for 0.5–12 kHz, a 10–60 dB DPOAE LS for 0.6–16 kHz and severe OHC loss in the middle of the first turn. When infrasound was present during exposure to the 4-kHz OBN at 108 dB, the functional losses and OHC losses extended much further toward the apical and basal tips of the OC than in cochleae exposed to the 4-kHz OBN alone. Exposure to only the 4-kHz OBN at 86 dB produces a 10–40 dB ABR TS for 3–12 kHz and 10–30 dB DPOAE LS for 3–8 kHz but little or no

  6. 3D measurements of ignition processes at 20 kHz in a supersonic combustor

    NASA Astrophysics Data System (ADS)

    Ma, Lin; Lei, Qingchun; Wu, Yue; Ombrello, Timothy M.; Carter, Campbell D.

    2015-05-01

    The ignition dynamics in a Mach 2 combustor were investigated using a three-dimensional (3D) diagnostic with 20 kHz temporal resolution. The diagnostic was based on a combination of tomographic chemiluminescence and fiber-based endoscopes (FBEs). Customized FBEs were employed to capture line-of-sight integrated chemiluminescence images (termed projections) of the combustor from eight different orientations simultaneously at 20 kHz. The measured projections were then used in a tomographic algorithm to obtain 3D reconstruction of the sparks, ignition kernel, and stable flame. Processing the reconstructions frame by frame resulted in 4D measurements. Key properties were then extracted to quantify the ignition processes, including 3D volume, surface area, sphericity, and velocity of the ignition kernel. The data collected in this work revealed detailed spatiotemporal dynamics of the ignition kernel, which are not obtainable with planar diagnostics, such as its growth, movement, and development into "stable" combustion. This work also illustrates the potential for obtaining quantitative 3D measurements using tomographic techniques and the practical utility of FBEs.

  7. Harvesting Low-Frequency (<5 Hz) Irregular Mechanical Energy: A Possible Killer Application of Triboelectric Nanogenerator.

    PubMed

    Zi, Yunlong; Guo, Hengyu; Wen, Zhen; Yeh, Min-Hsin; Hu, Chenguo; Wang, Zhong Lin

    2016-04-26

    Electromagnetic generators (EMGs) and triboelectric nanogenerators (TENGs) are the two most powerful approaches for harvesting ambient mechanical energy, but the effectiveness of each depends on the triggering frequency. Here, after systematically comparing the performances of EMGs and TENGs under low-frequency motion (<5 Hz), we demonstrated that the output performance of EMGs is proportional to the square of the frequency, while that of TENGs is approximately in proportion to the frequency. Therefore, the TENG has a much better performance than that of the EMG at low frequency (typically 0.1-3 Hz). Importantly, the extremely small output voltage of the EMG at low frequency makes it almost inapplicable to drive any electronic unit that requires a certain threshold voltage (∼0.2-4 V), so that most of the harvested energy is wasted. In contrast, a TENG has an output voltage that is usually high enough (>10-100 V) and independent of frequency so that most of the generated power can be effectively used to power the devices. Furthermore, a TENG also has advantages of light weight, low cost, and easy scale up through advanced structure designs. All these merits verify the possible killer application of a TENG for harvesting energy at low frequency from motions such as human motions for powering small electronics and possibly ocean waves for large-scale blue energy. PMID:27077467

  8. Spectroscopic study of 50 Hz pulsed Ar-O2 mixture plasma

    NASA Astrophysics Data System (ADS)

    Imran, M.; Rehman, N. U.; Khan, A. W.; Zaka-ul-Islam, M.; Shafiq, M.; Zakaullah, M.

    2016-06-01

    Plasma sterilization is widely used to disinfect the heat sensitive materials. In this study, we have investigated 50 Hz pulsed capacitively coupled plasma (CCP) system operated in Ar-O2 mixture. Optical emission spectroscopy (OES) is used to identify the optimum conditions suitable for plasma based sterilization. Explicitly, excitation temperature of Ar-I lines, atomic oxygen density, dissociation fraction and UV radiation intensity are measured as a function of discharge parameters. The excitation temperature is calculated using Boltzmann plot method whereas OES has also been employed to evaluate the ground state atomic oxygen density and dissociation fraction. Similarly the normalized UV radiation intensity is determined from UV spectrum in 200-400 nm range. The results show that the total UV emission has optimum value at 20% oxygen, 2 mbar pressure and 2.68 mA/cm2 current density in the mixture. While excitation temperature, atomic oxygen density and dissociation fraction increase with the current density. A comparison with the literature suggests 50 Hz CCP system operated in Ar-O2 mixture has the potential of a cheap and reliable system for plasma sterilization.

  9. High repetition rate (100 Hz), high peak power, high contrast femtosecond laser chain

    NASA Astrophysics Data System (ADS)

    Clady, R.; Tcheremiskine, V.; Azamoum, Y.; Ferré, A.; Charmasson, L.; Utéza, O.; Sentis, M.

    2016-03-01

    High intensity femtosecond laser are now routinely used to produce energetic particles and photons via interaction with solid targets. However, the relatively low conversion efficiency of such processes requires the use of high repetition rate laser to increase the average power of the laser-induced secondary source. Furthermore, for high intensity laser-matter interaction, a high temporal contrast is of primary importance as the presence of a ns ASE pedestal (Amplified Spontaneous Emission) and/or various prepulses may significantly affect the governing interaction processes by creating a pre-plasma on the target surface. We present the characterization of a laser chain based on Ti:Sa technology and CPA technique, which presents unique laser characteristics : a high repetition rate (100 Hz), a high peak power (>5 TW) and a high contrast ratio (ASE<10-10) obtained thanks to a specific design with 3 saturable absorbers inserted in the amplification chain. A deformable mirror placed before the focusing parabolic mirror should allow us to focus the beam almost at the limit of diffraction. In these conditions, peak intensity above 1019W.cm-2 on target could be achieved at 100 Hz, allowing the study of relativistic optics at a high repetition rate.

  10. 1 Hz linewidth Ti:sapphire laser as local oscillator for (40)Ca(+) optical clocks.

    PubMed

    Bian, Wu; Huang, Yao; Guan, Hua; Liu, Peiliang; Ma, Longsheng; Gao, Kelin

    2016-06-01

    A Ti:sapphire laser at 729 nm is frequency stabilized to an ultra-stable ultra-low thermal expansion coefficient (ULE) cavity by means of Pound-Drever-Hall method. An acousto-optic modulator is used as the fast frequency feedback component. 1 Hz linewidth and 2 × 10(-15) frequency stability at 1-100 s are characterized by optical beating with a separated Fabry-Perot cavity stabilized diode laser. Compared to the universal method that the error signal feedback to inject current of a diode laser, this scheme is demonstrated to be simple and also effective for linewidth narrowing. The temperature of zero coefficient of the thermal expansion of the ULE cavity is measured with the help of a femto-second frequency comb. And the performance of the laser is well defined by locking it to the unperturbed clock transition line-center of 4 S1/2-3 D5/2 clock transition of a single laser cooled (40)Ca(+) ion. A Fourier-transform limited resonance of 6 Hz (Δv/v = 1.5 × 10(-14)) is observed. This laser is also used as the local oscillator for the comparison experiment of two (40)Ca(+) ion optical clocks and improves the stability of comparison for an order of magnitude better than the previous results.

  11. Diurnal patterns in brain biogenic amines of rats exposed to 60-Hz electric fields

    SciTech Connect

    Vasquez, B.J.; Anderson, L.E.; Lowery, C.I.; Adey, W.R.

    1988-01-01

    Levels of brain neurotransmitters and their metabolites, as well as concentrations of enzymes associated with their synthesis and metabolism, fluctuate during the day in patterns defined as circadian. The present study examined these rhythms in albino rats exposed to 60-Hz electric fields. Thirty-six animals were exposed to a 39 kV/m field for 4 weeks, 20 h/day, in a parallel-plate electrode system. A group of 36 sham animals was similarly handled and housed in a nonenergized exposure system. On the sampling day, animals were sacrificed at 4-h intervals throughout the 24-h day. Brains were removed, dissected, and kept frozen until chemically analyzed. The levels of biogenic amines and their acidic metabolites in the striatum, hypothalamus, and hippocampus were determined by high-performance liquid chromatography with electrochemical detection (HPLC-ECD) methods. Repeated exposure to 60-Hz electric fields produced significant alterations in the diurnal rhythms of several biogenic amines: dihydroxyphenylacetic acid (DOPAC, the primary metabolite of dopamine in the rat) in the striatum, and norepinephrine, dopamine, and 5-hydroxyindoleacetic acid (5-HIAA; serotonin metabolite) in the hypothalamus. Levels of serotonin in the striatum and hypothalamus showed clear circadian patterns that was not affected by the field. No diurnal or field-related changes were observed in the hippocampal amines.

  12. a Thermoacoustically-Driven Pulse Tube Cryocryocooler Operating around 300HZ

    NASA Astrophysics Data System (ADS)

    Yu, G. Y.; Zhu, S. L.; Dai, W.; Luo, E. C.

    2008-03-01

    High frequency operation of the thermoacoustic cryocooler system, i.e. pulse tube cryocooler driven by thermoacoustic engine, leads to reduced size, which is quite attractive to small-scale cryogenic applications. In this work, a no-load coldhead temperature of 77.8 K is achieved on a 292 Hz pulse tube cryocooler driven by a standing-wave thermoacoustic engine with 3.92 MPa helium gas and 1750 W heat input. To improve thermal efficiency, a high frequency thermoacoustic-Stirling heat engine is also built to drive the same pulse tube cryocooler, and a no-load temperature of 109 K was obtained with 4.38 MPa helium gas, 292 Hz working frequency and 400W heating power. Ideas such as tapered resonators, acoustic amplifier tubes and simple thin tubes without reservoir are used to effectively suppress harmonic modes, amplify the acoustic pressure wave available to the pulse tube cryocooler and provide desired acoustic impedance for the pulse tube cryocooler, respectively. Comparison of systems with different thermoacoustic engines is made. Numerical simulations based on the linear thermoacoustic theory have also been done for comparison with experimental results, which shows reasonable agreement.

  13. Reducing the Heat Load on the LCLS 120 Hz RF Gun with RF Pulse Shaping

    SciTech Connect

    Schmerge, J.

    2005-01-31

    The LCLS injector must operate at 120 Hz repetition frequency but to date the maximum operating frequency of an S-band rf gun has been 50 Hz. The high fields desired for the LCLS gun operation limit the repetition frequency due to thermal expansion causing rf detuning and field redistribution. One method of addressing the thermal loading problem is too reduce the power lost on the cavity walls by properly shaping the rf pulse incident on the gun. The idea is to reach the steady state field value in the gun faster than the time constant of the gun would allow when using a flat incident rf pulse. By increasing the incident power by about a factor of three and then decreasing the incident power when the field reaches the desired value in the gun, the field build up time can be decreased by more than a factor of three. Using this technique the heat load is also decreased by more than a factor of three. In addition the rf coupling coefficient can be increased from the typical critically coupled designs to an overcoupled design which also helps reduce the field build up time. Increasing the coupling coefficient from 1 to 2 reduces the heat load by another 25% and still limits the reflected power and coupling hole size to manageable levels.

  14. Biological studies of swine exposed to 60-Hz electric fields. Volume 7. Neurology. Final report

    SciTech Connect

    Not Available

    1985-12-01

    Neurophysiological responses in three generations of miniature swine chronically exposed to a 30-kV/m, 60-Hz electric field have been assessed in a series of screening experiments. Results are presented from experiments on peripheral nerve function in parental (F/sub 0/) female swine at 100 days of gestation, and from experiments on synaptic transmission in first- and second-generation (F/sub 1/ and F/sub 2/) progeny at 6 weeks of age, all following chronic exposure to a 60-Hz electric field. In the several measures of peripheral nerve function examined, only two showed consistent differences between exposed and sham-exposed animals: C-fiber (but not B-fiber) conduction velocity was decreased in nerve preparations from exposed swine, and recovery, as measured by the increase in amplitude of the compound action potential, was consistently, although not statistically, less in B- and C-fibers from exposed animals when compared to values for the sham-exposed controls. Although changes (increases or decreases) in various parameters of synaptic transmission were observed between exposed and sham-exposed groups, the differences were not consistent across experiments or generations. Only one measure of synaptic function showed a consistent difference throughout the studies: the conduction velocities of B and C components of the postsynaptic compound action potential were increased following electric-field exposure (statistically significant only in B-fibers of the F/sub 2/ generations). 7 refs., 60 figs., 17 tabs.

  15. 1 Hz linewidth Ti:sapphire laser as local oscillator for (40)Ca(+) optical clocks.

    PubMed

    Bian, Wu; Huang, Yao; Guan, Hua; Liu, Peiliang; Ma, Longsheng; Gao, Kelin

    2016-06-01

    A Ti:sapphire laser at 729 nm is frequency stabilized to an ultra-stable ultra-low thermal expansion coefficient (ULE) cavity by means of Pound-Drever-Hall method. An acousto-optic modulator is used as the fast frequency feedback component. 1 Hz linewidth and 2 × 10(-15) frequency stability at 1-100 s are characterized by optical beating with a separated Fabry-Perot cavity stabilized diode laser. Compared to the universal method that the error signal feedback to inject current of a diode laser, this scheme is demonstrated to be simple and also effective for linewidth narrowing. The temperature of zero coefficient of the thermal expansion of the ULE cavity is measured with the help of a femto-second frequency comb. And the performance of the laser is well defined by locking it to the unperturbed clock transition line-center of 4 S1/2-3 D5/2 clock transition of a single laser cooled (40)Ca(+) ion. A Fourier-transform limited resonance of 6 Hz (Δv/v = 1.5 × 10(-14)) is observed. This laser is also used as the local oscillator for the comparison experiment of two (40)Ca(+) ion optical clocks and improves the stability of comparison for an order of magnitude better than the previous results. PMID:27370440

  16. Dielectric dispersion of water in the frequency range from 10 mHz to 30 MHz.

    PubMed

    Batalioto, F; Duarte, A R; Barbero, G; Neto, A M F

    2010-03-18

    We investigate the dielectric dispersion of water, specially in the low-frequency range, by using the impedance spectroscopy technique. The frequency dependencies of the real R and imaginary chi parts of the impedance could not be explained by means of the usual description of the dielectric properties of the water as an insulating liquid containing ions. This is due to the incomplete knowledge of the parameters entering in the fundamental equations describing the evolution of the system, and on the mechanisms regulating the exchange of charge of the cell with the external circuit. We propose a simple description of our experimental data based on the model of Debye, by invoking a dc conductivity of the cell, related to the nonblocking character of the electrodes. A discussion on the electric circuits able to simulate the cell under investigation, based on bulk and surface elements, is also reported. We find that the simple circuit formed by a series of two parallels of resistance and capacitance is able to reproduce the experimental data concerning the real and imaginary part of the electrical impedance of the cell for frequency larger than 1 Hz. According to this description, one of the parallels takes into account the electrical properties of interface between the electrode and water, and the other of the bulk. For frequency lower than 1 Hz, a good agreement with the experimental data is obtained by simulating the electrical properties of the interface by means of the constant phase element.

  17. Tri-linear color multi-linescan sensor with 200 kHz line rate

    NASA Astrophysics Data System (ADS)

    Schrey, Olaf; Brockherde, Werner; Nitta, Christian; Bechen, Benjamin; Bodenstorfer, Ernst; Brodersen, Jörg; Mayer, Konrad J.

    2016-11-01

    In this paper we present a newly developed linear CMOS high-speed line-scanning sensor realized in a 0.35 μm CMOS OPTO process for line-scan with 200 kHz true RGB and 600 kHz monochrome line rate, respectively. In total, 60 lines are integrated in the sensor allowing for electronic position adjustment. The lines are read out in rolling shutter manner. The high readout speed is achieved by a column-wise organization of the readout chain. At full speed, the sensor provides RGB color images with a spatial resolution down to 50 μm. This feature enables a variety of applications like quality assurance in print inspection, real-time surveillance of railroad tracks, in-line monitoring in flat panel fabrication lines and many more. The sensor has a fill-factor close to 100%, preventing aliasing and color artefacts. Hence the tri-linear technology is robust against aliasing ensuring better inspection quality and thus less waste in production lines.

  18. A microrod-resonator Brillouin laser with 240 Hz absolute linewidth

    NASA Astrophysics Data System (ADS)

    Loh, William; Becker, Joe; Cole, Daniel C.; Coillet, Aurelien; Baynes, Fred N.; Papp, Scott B.; Diddams, Scott A.

    2016-04-01

    We demonstrate an ultralow-noise microrod-resonator based laser that oscillates on the gain supplied by the stimulated Brillouin scattering optical nonlinearity. Microresonator Brillouin lasers are known to offer an outstanding frequency noise floor, which is limited by fundamental thermal fluctuations. Here, we show experimental evidence that thermal effects also dominate the close-to-carrier frequency fluctuations. The 6 mm diameter microrod resonator used in our experiments has a large optical mode area of ∼100 μm2, and hence its 10 ms thermal time constant filters the close-to-carrier optical frequency noise. The result is an absolute laser linewidth of 240 Hz with a corresponding white-frequency noise floor of 0.1 Hz2 Hz‑1. We explain the steady-state performance of this laser by measurements of its operation state and of its mode detuning and lineshape. Our results highlight a mechanism for noise that is common to many microresonator devices due to the inherent coupling between intracavity power and mode frequency. We demonstrate the ability to reduce this noise through a feedback loop that stabilizes the intracavity power.

  19. Attempts to produce taste-aversion learning in rats exposed to 60-Hz electric fields

    SciTech Connect

    Creim, J.A.; Lovely, R.H.; Kaune, W.T.; Phillips, R.D.

    1984-01-01

    A measure of taste-aversion (TA) learning was used in three experiments to 1) determine whether exposure to intense 60-Hz electric fields can produce TA learning in male Sprague-Dawley rats, and (2) establish a dose-response function for the behavior in question. In Experiment 1, four groups of eight rats each were distributed into one of two exposures (69 +/- 5 kV/m or 133 +/- 10 kV/m) or into one of two sham-exposure groups. Conditioning trials paired 0.1% sodium saccharin in water with 3 h of exposure to a 60-Hz electric field. Following five conditioning trials, a 20-min, two-bottle preference test between water and saccharin-flavored water failed to reveal TA conditioning in exposed groups. In Experiment 2, four groups of eight rats each (34 +/- 2 kV/m or 133 +/- 10 kV/m and two sham-exposed groups) were treated as before. Electric-field exposure had no effect on TA learning. Experiment 3 tested for a possible synergy between a minimal dose (for TA learning) of cyclophosphamide (6 mg/kg) and 5 h of exposure to 133 +/- 10 kV/m electric fields in a dark environment under conditions otherwise similar to those of Experiments 1 and 2. The results indicated no TA learning as reflected in the relative consumption of saccharin. 16 references, 6 figures, 1 table.

  20. Harvesting Low-Frequency (<5 Hz) Irregular Mechanical Energy: A Possible Killer Application of Triboelectric Nanogenerator.

    PubMed

    Zi, Yunlong; Guo, Hengyu; Wen, Zhen; Yeh, Min-Hsin; Hu, Chenguo; Wang, Zhong Lin

    2016-04-26

    Electromagnetic generators (EMGs) and triboelectric nanogenerators (TENGs) are the two most powerful approaches for harvesting ambient mechanical energy, but the effectiveness of each depends on the triggering frequency. Here, after systematically comparing the performances of EMGs and TENGs under low-frequency motion (<5 Hz), we demonstrated that the output performance of EMGs is proportional to the square of the frequency, while that of TENGs is approximately in proportion to the frequency. Therefore, the TENG has a much better performance than that of the EMG at low frequency (typically 0.1-3 Hz). Importantly, the extremely small output voltage of the EMG at low frequency makes it almost inapplicable to drive any electronic unit that requires a certain threshold voltage (∼0.2-4 V), so that most of the harvested energy is wasted. In contrast, a TENG has an output voltage that is usually high enough (>10-100 V) and independent of frequency so that most of the generated power can be effectively used to power the devices. Furthermore, a TENG also has advantages of light weight, low cost, and easy scale up through advanced structure designs. All these merits verify the possible killer application of a TENG for harvesting energy at low frequency from motions such as human motions for powering small electronics and possibly ocean waves for large-scale blue energy.

  1. Quasi-periodic (~mHz) dayside auroral brightennings associated with high-speed solar wind

    NASA Astrophysics Data System (ADS)

    Liou, K.

    2013-12-01

    It has been reported that dayside auroral pulsations of a few mHz frequency can occur when variations of solar wind dynamic pressure at the same frequency appear. Magnetospheric compression/decompression is attributed to the auroral pulsations. Here we report another type of dayside auroral pulsations not associated with solar wind dynamic pressure changes by using global auroral images acquired from the Ultraviolet Imager (UVI) on board the Polar satellite. From one periodic (~2 - 8 mHz) auroral event that occurred on February 8, 2000, it is found that the auroral enhancements covered most of the day (~05 - 16 MLT) sector and did not show a latitudinal dependence. Based on in situ particle data from DMSP SSJ/4, the brightennings were associated mainly with enhanced particle precipitations from the central plasma sheet (i.e., diffuse aurora). There was no geomagnetic pulsation on the ground and in the dawn sector of the magnetosheath as indicated by the Geotail measurements. While the auroral pulsations occurred during high solar wind speed (> 600 km/s), they commenced when the interplanetary magnetic field turned northward, suggesting the Kelvin-Helmholtz instability being a source of the pulsations. We will present detail analysis results and discuss other possible mechanisms in the context of current theories.

  2. 1 Hz linewidth Ti:sapphire laser as local oscillator for 40Ca+ optical clocks

    NASA Astrophysics Data System (ADS)

    Bian, Wu; Huang, Yao; Guan, Hua; Liu, Peiliang; Ma, Longsheng; Gao, Kelin

    2016-06-01

    A Ti:sapphire laser at 729 nm is frequency stabilized to an ultra-stable ultra-low thermal expansion coefficient (ULE) cavity by means of Pound-Drever-Hall method. An acousto-optic modulator is used as the fast frequency feedback component. 1 Hz linewidth and 2 × 10-15 frequency stability at 1-100 s are characterized by optical beating with a separated Fabry-Perot cavity stabilized diode laser. Compared to the universal method that the error signal feedback to inject current of a diode laser, this scheme is demonstrated to be simple and also effective for linewidth narrowing. The temperature of zero coefficient of the thermal expansion of the ULE cavity is measured with the help of a femto-second frequency comb. And the performance of the laser is well defined by locking it to the unperturbed clock transition line-center of 4 S1/2-3 D5/2 clock transition of a single laser cooled 40Ca+ ion. A Fourier-transform limited resonance of 6 Hz (Δv/v = 1.5 × 10-14) is observed. This laser is also used as the local oscillator for the comparison experiment of two 40Ca+ ion optical clocks and improves the stability of comparison for an order of magnitude better than the previous results.

  3. 35 Hz shape memory alloy actuator with bending-twisting mode

    PubMed Central

    Song, Sung-Hyuk; Lee, Jang-Yeob; Rodrigue, Hugo; Choi, Ik-Seong; Kang, Yeon June; Ahn, Sung-Hoon

    2016-01-01

    Shape Memory Alloy (SMA) materials are widely used as an actuating source for bending actuators due to their high power density. However, due to the slow actuation speed of SMAs, there are limitations in their range of possible applications. This paper proposes a smart soft composite (SSC) actuator capable of fast bending actuation with large deformations. To increase the actuation speed of SMA actuator, multiple thin SMA wires are used to increase the heat dissipation for faster cooling. The actuation characteristics of the actuator at different frequencies are measured with different actuator lengths and results show that resonance can be used to realize large deformations up to 35 Hz. The actuation characteristics of the actuator can be modified by changing the design of the layered reinforcement structure embedded in the actuator, thus the natural frequency and length of an actuator can be optimized for a specific actuation speed. A model is used to compare with the experimental results of actuators with different layered reinforcement structure designs. Also, a bend-twist coupled motion using an anisotropic layered reinforcement structure at a speed of 10 Hz is also realized. By increasing their range of actuation characteristics, the proposed actuator extends the range of application of SMA bending actuators. PMID:26892438

  4. Dielectric dispersion of water in the frequency range from 10 mHz to 30 MHz.

    PubMed

    Batalioto, F; Duarte, A R; Barbero, G; Neto, A M F

    2010-03-18

    We investigate the dielectric dispersion of water, specially in the low-frequency range, by using the impedance spectroscopy technique. The frequency dependencies of the real R and imaginary chi parts of the impedance could not be explained by means of the usual description of the dielectric properties of the water as an insulating liquid containing ions. This is due to the incomplete knowledge of the parameters entering in the fundamental equations describing the evolution of the system, and on the mechanisms regulating the exchange of charge of the cell with the external circuit. We propose a simple description of our experimental data based on the model of Debye, by invoking a dc conductivity of the cell, related to the nonblocking character of the electrodes. A discussion on the electric circuits able to simulate the cell under investigation, based on bulk and surface elements, is also reported. We find that the simple circuit formed by a series of two parallels of resistance and capacitance is able to reproduce the experimental data concerning the real and imaginary part of the electrical impedance of the cell for frequency larger than 1 Hz. According to this description, one of the parallels takes into account the electrical properties of interface between the electrode and water, and the other of the bulk. For frequency lower than 1 Hz, a good agreement with the experimental data is obtained by simulating the electrical properties of the interface by means of the constant phase element. PMID:20178324

  5. Biologic effects of prolonged exposure to ELF electromagnetic fields in rats. 2: 50 Hz magnetic fields

    SciTech Connect

    Margonato, V.; Cerretelli, P.; Nicolini, P.; Conti, R.; Zecca, L.; Veicsteinas, Z.

    1995-12-31

    To provide possible laboratory support to health risk evaluation associated with long-term, low-intensity magnetic field exposure, 256 male albino rats and an equal number of control animals (initial age 12 weeks) were exposed 22 h/day to a 50 Hz magnetic flux density of 5 {micro}T for 32 weeks (a total of about 5,000 h). Hematology was studied from blood samples before exposure to the field and at 12 week intervals. Morphology and histology of liver, heart, mesenteric lymph nodes, and testes as well as brain neurotransmitters were assessed at the end of the exposure period. In two identical sets of experiments, no significant differences in the investigated variables were found between exposed and sham-exposed animals. It is concluded that continuous exposure to a 50 Hz magnetic field of 5 {micro}T from week 12 to week 44, which makes up {approximately}70% of the life span of the rat before sacrifice, does not cause changes in growth rate, in the morphology and histology of liver, heart, mesenteric lymph nodes, testes, and bone marrow, in hematology and hematochemistry, or in the neurotransmitters dopamine and serotonin.

  6. Multi-mJ, kHz, ps deep-ultraviolet source.

    PubMed

    Chang, Chun-Lin; Krogen, Peter; Liang, Houkun; Stein, Gregory J; Moses, Jeffrey; Lai, Chien-Jen; Siqueira, Jonathas P; Zapata, Luis E; Kärtner, Franz X; Hong, Kyung-Han

    2015-02-15

    We demonstrate a 0.56-GW, 1-kHz, 4.2-ps, 2.74-mJ deep-ultraviolet (DUV) laser at ∼257.7  nm with a beam propagation factor (M2) of ∼2.54 from a frequency-quadrupled cryogenic multi-stage Yb-doped chirped-pulse amplifier. The frequency quadrupling is achieved using LiB3O5 and β-BaB2O4 crystals for near-infrared (NIR)-to-green and green-to-DUV conversion, respectively. An overall NIR-to-DUV efficiency of ∼10% has been achieved, which is currently limited by the thermal-induced phase mismatching and the DUV-induced degradation of transmittance. To the best of our knowledge, this is the highest peak-power picosecond DUV source from a diode-pumped solid-state laser operating at kHz repetition rates. PMID:25680176

  7. Occipital gamma activation during Vipassana meditation.

    PubMed

    Cahn, B Rael; Delorme, Arnaud; Polich, John

    2010-02-01

    Long-term Vipassana meditators sat in meditation vs. a control rest (mind-wandering) state for 21 min in a counterbalanced design with spontaneous EEG recorded. Meditation state dynamics were measured with spectral decomposition of the last 6 min of the eyes-closed silent meditation compared to control state. Meditation was associated with a decrease in frontal delta (1-4 Hz) power, especially pronounced in those participants not reporting drowsiness during meditation. Relative increase in frontal theta (4-8 Hz) power was observed during meditation, as well as significantly increased parieto-occipital gamma (35-45 Hz) power, but no other state effects were found for the theta (4-8 Hz), alpha (8-12 Hz), or beta (12-25 Hz) bands. Alpha power was sensitive to condition order, and more experienced meditators exhibited no tendency toward enhanced alpha during meditation relative to the control task. All participants tended to exhibit decreased alpha in association with reported drowsiness. Cross-experimental session occipital gamma power was the greatest in meditators with a daily practice of 10+ years, and the meditation-related gamma power increase was similarly the strongest in such advanced practitioners. The findings suggest that long-term Vipassana meditation contributes to increased occipital gamma power related to long-term meditational expertise and enhanced sensory awareness.

  8. Doubly Fed Induction Generator in an Offshore Wind Power Plant Operated at Rated V/Hz: Preprint

    SciTech Connect

    Muljadi, E.; Singh, M.; Gevorgian, V.

    2012-06-01

    This paper introduces the concept of constant Volt/Hz operation of offshore wind power plants. The deployment of offshore WPPs requires power transmission from the plant to the load center inland. Since this power transmission requires submarine cables, there is a need to use High-Voltage Direct Current transmission, which is economical for transmission distances longer than 50 kilometers. In the concept presented here, the onshore substation is operated at 60 Hz synced with the grid, and the offshore substation is operated at variable frequency and voltage, thus allowing the WPP to be operated at constant Volt/Hz.

  9. Possible generation mechanisms of low-frequency waves /less than about 50 Hz/ with application to the bow shock plasma

    NASA Technical Reports Server (NTRS)

    Dangelo, N.

    1979-01-01

    Generation mechanisms of waves observed at the earth's bow shock or in its vicinity within the frequency range extending up to about 50 Hz are reviewed. Observations and theories regarding waves in the solar wind upstream of the bow shock (both low-frequency 0.01-0.05 Hz and high-frequency 0.5-4 Hz waves), waves in the bow shock itself and magnetosheath waves arising from processes of generation or amplification in the bow shock are considered. Hydromagnetic, ion-acoustic and whistler type waves are discussed.

  10. High power Yb:YAG diode pumped LUCIA front-end oscillator (250 mJ, 50 ns, 2 Hz).

    NASA Astrophysics Data System (ADS)

    Bahbah, S.; Albach, D.; Assémat, F.; Bourdet, G.; Chanteloup, J.-C.; Piatti, P.; Pluvinage, M.; Vincent, B.; Touzé, G. L.

    2008-05-01

    The LULI laboratory is building a new intense laser chain with an energy goal of 100, J and at high repetition rate (10 Hz). This chain, called LUCIA, is composed of an oscillator and two diode pumped Yb:YAG amplifiers. We will show the progress of our work on the oscillator. In terms of performance in free running regime, we reach energies of about 4 J at 2 Hz with diode pumping energies of 11, J. In Q-switch regime 49ns long pulses at a repetition rate of 2 Hz were observed.

  11. The interaction of respiration and visual feedback on the control of force and neural activation of the agonist muscle.

    PubMed

    Baweja, Harsimran S; Patel, Bhavini K; Neto, Osmar P; Christou, Evangelos A

    2011-12-01

    The purpose of this study was to compare force variability and the neural activation of the agonist muscle during constant isometric contractions at different force levels when the amplitude of respiration and visual feedback were varied. Twenty young adults (20-32 years, 10 men and 10 women) were instructed to accurately match a target force at 15% and 50% of their maximal voluntary contraction (MVC) with abduction of the index finger while controlling their respiration at different amplitudes (85%, 100% and 125% normal) in the presence and absence of visual feedback. Each trial lasted 22s and visual feedback was removed from 8-12 and 16-20s. Each subject performed three trials with each respiratory condition at each force level. Force variability was quantified as the standard deviation of the detrended force data. The neural activation of the first dorsal interosseus (FDI) was measured with bipolar surface electrodes placed distal to the innervation zone. Relative to normal respiration, force variability increased significantly only during high-amplitude respiration (∼63%). The increase in force variability from normal- to high-amplitude respiration was strongly associated with amplified force oscillations from 0 to 3 Hz (R(2) ranged from .68 to .84, p< .001). Furthermore, the increase in force variability was exacerbated in the presence of visual feedback at 50% MVC (vision vs. no-vision: .97 vs. .87N) and was strongly associated with amplified force oscillations from 0 to 1 Hz (R(2)= .82) and weakly associated with greater power from 12 to 30 Hz (R(2)= .24) in the EMG of the agonist muscle. Our findings demonstrate that high-amplitude respiration and visual feedback of force interact and amplify force variability in young adults during moderate levels of effort.

  12. Greater amount of visual feedback decreases force variability by reducing force oscillations from 0–1 and 3–7 Hz

    PubMed Central

    Baweja, Harsimran S.; Kennedy, Deanna M.; Vu, Julie; Vaillancourt, David E.

    2010-01-01

    The purpose was to determine the relation between visual feedback gain and variability in force and whether visual gain-induced changes in force variability were associated with frequency-specific force oscillations and changes in the neural activation of the agonist muscle. Fourteen young adults (19–29 years) were instructed to accurately match the target force at 2 and 10% of their maximal voluntary contraction with abduction of the index finger. Force was maintained at specific visual feedback gain levels that varied across trials. Each trial lasted 20 s and the amount of visual feedback was varied by changing the visual gain from 0.5 to 1,474 pixels/N (13 levels; equals ~0.001–4.57°). Force variability was quantified as the standard deviation of the detrended force data. The neural activation of the first dorsal interosseus (FDI) was measured with surface electromyography. The mean force did not vary significantly with the amount of visual feedback. In contrast, force variability decreased from low gains compared to moderate gains (0.5–4 pixels/N: 0.09 ± 0.04 vs. 64–1,424 pixels/N: 0.06 ± 0.02 N). The decrease in variability was predicted by a decrease in the power of force oscillations from 0–1 Hz (~50%) and 3–7 Hz (~20%). The activity of the FDI muscle did not vary across the visual feedback gains. These findings demonstrate that in young adults force variability can be decreased with increased visual feedback gain (>64 pixels/N vs. 0.5–4 pixels/N) due to a decrease in the power of oscillations in the force from 0–1 and 3–7 Hz. PMID:19953262

  13. Relation of the enhancement of entorhinal tetanic responses by 50-Hz amygdala stimulation to the progression of kindling in the rat.

    PubMed

    Tanaka, K; Hirayama, K; Murata, R; Matsuura, S

    1995-10-01

    We recorded entorhinal tetanic responses to 50-Hz kindling stimulations applied at the amygdala in conscious rats, which produced facilitation and depression during the train pulses, in order to analyze the relationship of the changes in the tetanic responses to the development of both after-discharges (ADs) and behavioral seizures. Facilitation was always produced in the earlier tetanic responses and was followed by depression which reached a quasi-steady level in the later tetanic responses during each kindling stimulation. To estimate the changes in magnitude of the excitatory synaptic activation in the tetanic responses, with reference to the development of seizure stages, tetanic responses which produced the same behavioral seizure stage in each rat were averaged and the area between the negative (excitatory) potentials and the baseline of the averaged tetanic response was measured in terms of mV x ms. Magnitudes of the averaged negative components were significantly enhanced with an increase in the order of seizure stages in eight rats (P < 0.01). In addition, the mean magnitude of the averaged negative components had a linear correlation (r = 0.95, P < 0.05) with the mean AD duration with reference to the order of seizure stages in the eight rats. The magnitude of the positive (inhibitory) component in the averaged tetanic responses was also measured and found to decrease with an increase in the seizure stages (P < 0.01). The magnitude of the negative component in the test responses to single (0.3 Hz) stimuli just before kindling stimulations also increased with an increase in the order of seizure stages, indicating long term potentiation of the responses by kindling stimulations. We concluded from the results that the enhancement of facilitation of the excitatory synaptic activation and the reduction of the inhibitory synaptic activation in entorhinal tetanic responses by 50-Hz amygdala kindling stimulation is involved in the electrophysiological source of

  14. arsRBOCT Arsenic Resistance System Encoded by Linear Plasmid pHZ227 in Streptomyces sp. Strain FR-008

    PubMed Central

    Wang, Lianrong; Chen, Shi; Xiao, Xiang; Huang, Xi; You, Delin; Zhou, Xiufen; Deng, Zixin

    2006-01-01

    In the arsenic resistance gene cluster from the large linear plasmid pHZ227, two novel genes, arsO (for a putative flavin-binding monooxygenase) and arsT (for a putative thioredoxin reductase), were coactivated and cotranscribed with arsR1-arsB and arsC, respectively. Deletion of the ars gene cluster on pHZ227 in Streptomyces sp. strain FR-008 resulted in sensitivity to arsenic, and heterologous expression of the ars gene cluster in the arsenic-sensitive Streptomyces strains conferred resistance on the new hosts. The pHZ227 ArsB protein showed homology to the yeast arsenite transporter Acr3p. The pHZ227 ArsC appears to be a bacterial thioredoxin-dependent ArsC-type arsenate reductase with four conserved cysteine thioredoxin-requiring motifs. PMID:16672525

  15. Intermittent 20-HZ-photic stimulation leads to a uniform reduction of alpha-global field power in healthy volunteers.

    PubMed

    Rau, R; Raschka, C; Koch, H J

    2001-01-01

    19-channel-EEGs were recorded from scalp surface of 30 healthy subjects (16m, 14f, mean age: 34 ys, SD: 11.7 ys) at rest and under IPS (Intermittent Photic Stimulation) at rates of 5, 10 and 20 Hertz (Hz). Digitalized data underwent spectral analysis with fast fourier transfomation (FFT) yielding the basis for the computation of global field power (GFP). For quantification GFP values in the frequency ranges of 5, 10 and 20 Hz at rest were divided by the corresponding data gained under IPS. While ratios from PDE data showed no stable parameter due to high interindividual variability, ratios of alpha-power turned out to be uniform in all subjects: IPS at 20 Hz always led to a suppression of alpha-power. Dividing alpha-GFP at rest by alpha-GFP under 20-Hz IPS thus resulted in a ratio < 1. We conclude that ratios from GFP data are a stable diagnostic paradigma. PMID:11811850

  16. Intermittent 20-HZ-photic stimulation leads to a uniform reduction of alpha-global field power in healthy volunteers.

    PubMed

    Rau, R; Raschka, C; Koch, H J

    2001-01-01

    19-channel-EEGs were recorded from scalp surface of 30 healthy subjects (16m, 14f, mean age: 34 ys, SD: 11.7 ys) at rest and under IPS (Intermittent Photic Stimulation) at rates of 5, 10 and 20 Hertz (Hz). Digitalized data underwent spectral analysis with fast fourier transfomation (FFT) yielding the basis for the computation of global field power (GFP). For quantification GFP values in the frequency ranges of 5, 10 and 20 Hz at rest were divided by the corresponding data gained under IPS. While ratios from PDE data showed no stable parameter due to high interindividual variability, ratios of alpha-power turned out to be uniform in all subjects: IPS at 20 Hz always led to a suppression of alpha-power. Dividing alpha-GFP at rest by alpha-GFP under 20-Hz IPS thus resulted in a ratio < 1. We conclude that ratios from GFP data are a stable diagnostic paradigma.

  17. 60 Hz electric field changes the membrane potential during burst phase in pancreatic β-cells: in silico analysis.

    PubMed

    Neves, Gesilda F; Silva, José R F; Moraes, Renato B; Fernandes, Thiago S; Tenorio, Bruno M; Nogueira, Romildo A

    2014-06-01

    The production, distribution and use of electricity can generate low frequency electric and magnetic fields (50-60 Hz). Considering that some studies showed adverse effects on pancreatic β-cells exposed to these fields; the present study aimed to analyze the effects of 60 Hz electric fields on membrane potential during the silent and burst phases in pancreatic β-cells using a mathematical model. Sinusoidal 60 Hz electric fields with amplitude ranging from 0.5 to 4 mV were applied on pancreatic β-cells model. The sinusoidal electric field changed burst duration, inter-burst intervals (silent phase) and spike sizes. The parameters above presented dose-dependent response with the voltage amplitude applied. In conclusion, theoretical analyses showed that a 60 Hz electric field with low amplitudes changes the membrane potential in pancreatic β-cells.

  18. Neurochemical effects of a 20 kHz magnetic field on the central nervous system in prenatally exposed mice

    SciTech Connect

    Dimberg, Y.

    1995-09-01

    C57/B1 mice were exposed during pregnancy (gestation days 0--19) to a 20 kHz magnetic field (MF). The asymmetric sawtooth-waveform magnetic field in the exposed racks had a flux density of 15 {micro}T (peak to peak). After 19 days, the exposure was terminated, and the mice were housed individually under normal laboratory conditions. On postnatal day (PD) 1, PD21, and PD308, various neurochemical markers in the brains of the offspring were investigated and the brains weighed. No significant difference was found in the whole brain weight at PD1 or PD21 between exposed offspring and control animals. However, on PD308, a significant decrease in weight of the whole brain was detected in exposed animals. No significant differences were found in the weight of cortex, hippocampus, septum, or cerebellum on nay of the sampling occasions, nor were any significant differences detected in protein-, DNA-level, nerve growth factor (NGF), acetylcholine esterase- (AChE), or 2{prime},3{prime}-cyclic nucleotide 3{prime}-phosphodiesterase- (CNP; marker for oligodendrocytes) activities on PD21 in cerebellum. Cortex showed a more complex pattern of response to MF: MF treatment resulted in a decrease in DNA level and increases in the activities of CNP, AChE, and NGF protein. On PD308, the amount of DNA was significantly reduced in MF-treated cerebellum and CNP activity was still enhanced in MF-treated cortex compared to controls. Most of the effect of MF treatment during the embryonic period were similar to those induced by ionizing radiation but much weaker. However, the duration of the exposure required to elucidate the response of different markers to MF seems to be greater and effects appear later during development compared to responses to ionizing radiation.

  19. The validity and reliability of 5-Hz global positioning system units to measure team sport movement demands.

    PubMed

    Johnston, Richard J; Watsford, Mark L; Pine, Matthew J; Spurrs, Robert W; Murphy, Aron J; Pruyn, Elizabeth C

    2012-03-01

    The purpose of this research was to investigate the validity and the reliability of 5-Hz MinimaxX global positioning system (GPS) units measuring athlete movement demands. A team sport simulation circuit (files collected from each unit = 12) and flying 50-m sprints (files collected from each unit = 34) were undertaken, during which the total distance covered; peak speed; player load; the distance covered; time spent and number of efforts performed walking, jogging, running, high-speed running, and sprinting were examined. Movement demands were also separately categorized into low-intensity activity, high-intensity running, and very high-intensity running. The results revealed that GPS was a valid and reliable measure of total distance covered (p > 0.05, percentage typical error of measurement [%TEM] < 5%) and peak speed (p > 0.05, %TEM 5-10%). Further, GPS was found to be a reliable measure of player load (%TEM 4.9%) and the distance covered, time spent, and number of efforts performed at certain velocity zones (%TEM <5% to >10%). The level of GPS error was found to increase along with the velocity of exercise. The findings demonstrated that GPS is capable of measuring movement demands performed at velocities <20 km·h(-1), whereas more caution is to be exercised when analyzing movement demands collected by using GPS velocities >20 km·h(-1).

  20. Repeated intravenous cocaine experience: development and escalation of pre-drug anticipatory 50-kHz ultrasonic vocalizations in rats.

    PubMed

    Ma, Sean T; Maier, Esther Y; Ahrens, Allison M; Schallert, Timothy; Duvauchelle, Christine L

    2010-09-01

    Ultrasonic vocalization (USV) in the 50-kHz range occurs in rats immediately upon first-time exposure to cocaine or amphetamine, and rapidly increases with repetitive drug exposure at the same dose. This sensitized positive-affect response to these drugs of abuse is persistent in that the peak level of USVs again appears when the drug is reintroduced after several weeks of drug discontinuation. The present study explored whether with enough experience USVs might be elicited, and gradually escalate, in anticipation of impending drug delivery. Rats were trained to self-administer (SA) cocaine intravenously by lever pressing 5 days per week for 4 weeks. Yoked rats received experimenter-delivered cocaine matching that of SA rats. USVs and locomotor activity were recorded during each 10-min period prior to 60-min drug access sessions. Extinction trials in which drug access was denied were then carried out over an additional 4-week period. After about a week of cocaine experience, both the SA and yoked groups began to progressively increase USVs when placed in an environment that predicted forthcoming drug exposure. Extinction of anticipatory calls and locomotion occurred over days after drug access ended. USVs may be a useful model for specifically investigating the neural basis of drug anticipation and aid in developing and assessing new addiction treatment strategies for reducing craving and relapse.

  1. Effects of exposure to 30 kV/m, 60-Hz electric fields on the social behavior of baboons

    SciTech Connect

    Coelho, A.M. Jr.; Easley, S.P.; Rogers, W.R. )

    1991-01-01

    The authors tested the hypothesis that exposure to a 30-kV/m, 60-Hz electric field produces significant change (stress) in the social behavior of adult male baboons (Papio cynocephalus anubis). One group of eight baboons was exposed to an electric field (12 hours per day, 7 days per week for 6 weeks) while a second group of eight baboons was maintained in a sham-exposure (control) condition. Exposed subjects and control subjects were compared over three, six-week experimental periods (pre-exposure, exposure, and post-exposure). Performance rates of six categories of social behaviors (passive affinity, active affinity, approach, tension, threat, and attack) and four categories of nonsocial behaviors (forage, manipulate, posture, and stereotypy) were used to compare the two groups. The results of our study indicate that (1) there were no significant differences between the two groups during the pre-exposure or post-exposure periods; (2) during the exposure period, experimental and control groups exhibited statistically significant differences in the mean performance rates of three behavior categories; (3) within-group comparisons across periods indicate that the experimentally exposed group exhibited statistically significant changes in passive affinity, tension, and stereotypy; and (4) changes in behavior performance among the exposed subjects reflect a stress response to the electric field.

  2. Effect of ultraviolet B radiation and 100 Hz electromagnetic fields on proliferation and DNA synthesis of Jurkat cells.

    PubMed

    Nindl, G; Hughes, E F; Johnson, M T; Spandau, D F; Vesper, D N; Balcavage, W X

    2002-09-01

    The use of ultraviolet B light (UVB) has been proven to be highly effective for treatment of various inflammatory skin diseases, but UVB phototherapy is limited by its carcinogenic side effects. It is necessary to uncover effectors that augment UVB so that similar or improved efficacy can be obtained with lower UVB doses. We found that low frequency, low intensity electromagnetic fields (EMFs) can act as such an effector and synergistically inhibit T lymphocyte proliferation. We first characterized the effects of UVB on Jurkat cells, a model for cutaneous T lymphocytes, and determined UVB's dose dependent inhibition of cell proliferation and induction of apoptosis. Cells exposed to a sublethal UVB dose retained their sensitivity to UVB, but repetitive irradiation seemed to cause accumulation of delayed DNA damage. We then exposed cells to combinations of UVB plus EMFs and found that 100 Hz, 1 mT EMFs decrease DNA synthesis of UVB-activated Jurkat cells by 34 +/- 13% compared to UVB alone. The decrease is, however, most effective when relatively high UVB doses are employed. Since EMFs alone had only a very weak inhibitory effect (10 +/- 2%), the data suggest that EMFs augment the cell killing effects of UVB in a synergistic way. These findings could provide the basis for development of new and improved clinical phototherapy protocols.

  3. [HEALTH STATUS OF ELECTROTECHNICAL PERSONNEL EXPOSED TO THE COMBINED IMPACT OF ELECTROMAGNETIC FIELDS OF 50 HZ AND CHEMICALS].

    PubMed

    Rusin, M N; Amirov, N Kh; Sibgatullin, A S; Krasnoshchekova, V N

    2015-01-01

    There was performed an analysis of the working conditions and health status of workers of the chemical enterprise. In male electrical staff exposed to electromagnetic fields (EMF) of 50 Hz and chemicals, according to data of periodic medical examinations there was revealed statistically higher incidence of cardiovascular diseases and autonomic disorders. The obtained preliminary results allow to suggest the upsurge of the involvement of the autonomic nervous system in response to the combined effects of EMF of 50 Hz and chemicals.

  4. 200 Hz repetition frequency joule-level high beam quality Nd:YAG nanosecond laser

    NASA Astrophysics Data System (ADS)

    Qiu, Jisi; Tang, Xiongxin; Fan, Zhongwei; Wang, Haocheng

    2016-06-01

    A joule-level Nd:YAG nanosecond laser of high repetition frequency and high beam quality is developed out. The laser is designed as a MOPA system mainly including single longitudinal mode seed, pre-amplifier unit an d power amplifier unit. In order to obtain the high-quality laser beam output, phase conjugation is adopted to compensate the laser beam distortion. Under the condition of 200 Hz high repetition frequency and 8.19 μJ single pulse energy injected by the single longitudinal mode seed, 1.53 J output energy is gained. The output laser beam is of 9 mm diameter, 7.41 ns pulse width, the far field beam spot 1.32 times the value of the diffraction limit, 1.2% energy stability (RMS) and less than 13 μrad far field beam spot angle shift.

  5. Corticomuscular coherence is tuned to the spontaneous rhythmicity of speech at 2-3 Hz.

    PubMed

    Ruspantini, Irene; Saarinen, Timo; Belardinelli, Paolo; Jalava, Antti; Parviainen, Tiina; Kujala, Jan; Salmelin, Riitta

    2012-03-14

    Human speech features rhythmicity that frames distinctive, fine-grained speech patterns. Speech can thus be counted among rhythmic motor behaviors that generally manifest characteristic spontaneous rates. However, the critical neural evidence for tuning of articulatory control to a spontaneous rate of speech has not been uncovered. The present study examined the spontaneous rhythmicity in speech production and its relationship to cortex-muscle neurocommunication, which is essential for speech control. Our MEG results show that, during articulation, coherent oscillatory coupling between the mouth sensorimotor cortex and the mouth muscles is strongest at the frequency of spontaneous rhythmicity of speech at 2-3 Hz, which is also the typical rate of word production. Corticomuscular coherence, a measure of efficient cortex-muscle neurocommunication, thus reveals behaviorally relevant oscillatory tuning for spoken language.

  6. 50 kHz bottom backscattering measurements from two types of artificially roughened sandy bottoms

    NASA Astrophysics Data System (ADS)

    Son, Su-Uk; Cho, Sungho; Choi, Jee Woong

    2016-07-01

    Laboratory measurements of 50 kHz bottom backscattering strengths as a function of grazing angle were performed on the sandy bottom of a water tank; two types of bottom roughnesses, a relatively smooth interface and a rough interface, were created on the bottom surface. The roughness profiles of the two interface types were measured directly using an ultrasound arrival time difference of 5 MHz and then were Fourier transformed to obtain the roughness power spectra. The measured backscattering strengths increased from -29 to 0 dB with increasing grazing angle from 35 to 86°, which were compared to theoretical backscattering model predictions. The comparison results implied that bottom roughness is a key factor in accurately predicting bottom scattering for a sandy bottom.

  7. Exposure to high-frequency electromagnetic fields (100 kHz-2 GHz) in Extremadura (Spain).

    PubMed

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

    2011-12-01

    The last decade has seen a rapid increase in people's exposure to electromagnetic fields. This paper reports the measurements of radiofrequency (RF) total power densities and power density spectra in 35 towns of the region of Extremadura, Spain. The spectra were taken with three antennas covering frequencies from 100 kHz to 2.2 GHz. This frequency range includes AM/FM radio broadcasting, television, and cellular telephone signals. The power density data and transmitting antenna locations were stored in a geographic information system (GIS) as an aid in analyzing and interpreting the results. The results showed the power density levels to be below the reference level guidelines for human exposure and that the power densities are different for different frequency ranges and different size categories of towns.

  8. Space station 20-kHz power management and distribution system

    NASA Technical Reports Server (NTRS)

    Hansen, I. G.; Sundberg, G. R.

    1986-01-01

    During the conceptual design phase a 20-kHz power distribution system was selected as the reference for the space station. The system is single-phase 400 VRMS, with a sinusoidal wave form. The initial user power level will be 75 kW with growth to 300 kW. The high-frequency system selection was based upon considerations of efficiency, weight, safety, ease of control, interface with computers, and ease of paralleling for growth. Each of these aspects will be discussed as well as the associated trade-offs involved. An advanced development program has been instituted to accelerate the maturation of the high-frequency system. Some technical aspects of the advanced development will be discussed.

  9. Space Station 20-kHz power management and distribution system

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.; Sundberg, Gale R.

    1986-01-01

    During the conceptual design phase a 20-kHz power distribution system was selected as the reference for the Space Station. The system is single-phase 400 VRMS, with a sinusoidal wave form. The initial user power level will be 75 kW with growth to 300 kW. The high-frequency system selection was based upon considerations of efficiency, weight, safety, ease of control, interface with computers, and ease of paralleling for growth. Each of these aspects will be discussed as well as the associated trade-offs involved. An advanced development program has been instituted to accelerate the maturation of the high-frequency system. Some technical aspects of the advanced development will be discussed.

  10. Transmission line design for a power distribution system at 20 kHz for aircraft

    NASA Technical Reports Server (NTRS)

    Zelby, L. W.; Mathes, J. B.; Shawver, J. W.

    1986-01-01

    A low inductance, low characteristic impedance transmission line was designed for a 20 kHz power distribution system. Several different conductor configurations were considered: strip lines, interdigitated metal ribbons, and standard insulated wires in multiwire configurations (circular and rectangular cylindrical arrangements). The final design was a rectangular arrangement of multiple wires of the same gauge with alternating polarities from wire to wire. This offered the lowest inductance per unit length (on the order of several nanohenries/meter) and the lowest characteristic impedance (on the order of one Ohm). Standard multipin connectors with gold-plated elements were recommended with this transmission line, the junction boxes to be internally connected with flat metal ribbons for low inductance, and the line to be constructed in sections of suitable length. Computer programs for the calculation of inductance of multiwire lines and of capacitances of strip lines were developed.

  11. Test of a 1.8 Tesla, 400 Hz Dipole for a Muon Synchrotron

    SciTech Connect

    Summers, D.J.; Cremaldi, L.M.; Hart, T.L.; Perera, L.P.; Reep, M.; Witte, H.; Hansen, S.; Lopes, M.L.; Reidy Jr., J.; /Oxford High School

    2012-05-01

    A 1.8 T dipole magnet using thin grain oriented silicon steel laminations has been constructed as a prototype for a muon synchrotron ramping at 400 Hz. Following the practice in large 3 phase transformers and our own Opera-2d simulations, joints are mitred to take advantage of the magnetic properties of the steel which are much better in the direction in which the steel was rolled. Measurements with a Hysteresigraph 5500 and Epstein frame show a high magnetic permeability which minimizes stored energy in the yoke allowing the magnet to ramp quickly with modest voltage. Coercivity is low which minimizes hysteresis losses. A power supply with a fast Insulated Gate Bipolar Transistor (IGBT) switch and a capacitor was constructed. Coils are wound with 12 gauge copper wire. Thin wire and laminations minimize eddy current losses. The magnetic field was measured with a peak sensing Hall probe.

  12. Detection and temporal coherence of p-modes below 1.4 mHz

    NASA Astrophysics Data System (ADS)

    Eff-Darwich, A.; Régulo, C.; Korzennik, S. G.; Pérez Hernández, F.; Roca Cortés, T.

    2008-06-01

    Data collected recently by the helioseismic experiments aboard the SOHO spacecraft have allowed the detection of low degree p-modes with increasingly lower order n. In particular, the GOLF experiment is currently able to unambiguously identify low degree modes with frequencies as low as 1.3 mHz. The detection of p-modes with very low frequency ({i.e.}, low n), is difficult due to the low signal-to-noise ratio in this spectral region and its contamination by solar signals that are not of acoustic origin. To address this problem without using any theoretical a priory, we propose a methodology that relies only on the inversion of observed values to define a spectral window for the expected locations of these low frequency modes. The application of this method to 2920-day-long GOLF observations is presented and its results discussed.

  13. A 10-Hz Terawatt Class Ti:Sapphire Laser System: Development and Applications

    SciTech Connect

    Sharma, A.K.; Smedley, J.; Tsang, T.; Rao, T.

    2010-01-12

    We developed a two stage Ti:Sapphire laser system to generate 16 mJ/80fs laser pulses at the pulse repetition rate of 10 Hz. The key deriver for the present design is implementing a highly efficient symmetric confocal pre-amplifier and employing a simple, inexpensive synchronization scheme relying only on a commercial digital delay-generator. We characterized the amplified pulses in spatial-, spectral-, and temporal-domains. The laser system was used to investigate various nonlinear optical processes, and to modify the optical properties of metal- and semiconductor-surfaces. We are currently building a third amplifier to boost the laser power to the multi-terawatt range.

  14. Low frequency band gaps below 10 Hz in radial flexible elastic metamaterial plate

    NASA Astrophysics Data System (ADS)

    Gao, Nansha; Hou, Hong; Wu, Jiu Hui; Cheng, Baozhu

    2016-11-01

    This paper presents the low frequency acoustic properties of a new proposed elastic metamaterial, which is arranged in the axial coordinate. The band structures, transmission spectra, and eigenmode displacement fields of this metamaterial are different from previous elastic metamaterial structures. Numerical calculation results show that the first order band gap of the radial flexible elastic metamaterial plate is below 10 Hz. A multiple-vibration coupling mechanism is proposed to explain the low frequency band gaps. By changing the geometrical dimensions h 1, h 2, b 1, and b 1 of the centre part, the location and width of the low frequency band gaps can be varied easily. The effects of density and Young’s modulus are also discussed in detail. In summary, the radial flexible elastic metamaterial plate can restrain low frequency vibration, owing to which it can potentially be used to protect infrasound, generate filters, and design acoustic devices.

  15. Three-dimensional magnetic cloak working from d.c. to 250 kHz.

    PubMed

    Zhu, Jianfei; Jiang, Wei; Liu, Yichao; Yin, Ge; Yuan, Jun; He, Sailing; Ma, Yungui

    2015-01-01

    Invisible cloaking is one of the major outcomes of the metamaterial research, but the practical potential, in particular for high frequencies (for example, microwave to visible light), is fatally challenged by the complex material properties they usually demand. On the other hand, it will be advantageous and also technologically instrumental to design cloaking devices for applications at low frequencies where electromagnetic components are favourably uncoupled. In this work, we vastly develop the bilayer approach to create a three-dimensional magnetic cloak able to work in both static and dynamic fields. Under the quasi-static approximation, we demonstrate a perfect magnetic cloaking device with a large frequency band from 0 to 250 kHz. The practical potential of our device is experimentally verified by using a commercial metal detector, which may lead us to having a real cloaking application where the dynamic magnetic field can be manipulated in desired ways. PMID:26596641

  16. Effects of 60 Hz electrical fields on operant and social stress behaviors of nonhuman primates: Summary

    SciTech Connect

    Rogers, W.R.; Coelho, A.M. Jr.; Easley, S.P.; Orr, J.L.

    1988-04-06

    The objective of this program is to investigate, using the baboon as a nonhuman primate surrogate for the human, behavioral effects associated with exposure to 60-Hz electric fields. Results from this program, along with information from experiments conducted elsewhere, could be used to estimate and evaluate the likelihood of deleterious consequences resulting from exposure of humans to the electric fields associated with power transmission over high voltage lines. This program is being conducted at Southwest Research Institute as part of an international collaborative information exchange and scientific research effort involving the United State Department of Energy, Japan's Ministry of International Trade and Industry, and Japan's Central Research Institute of the Electric Power Industry. Since August of 1984, four major research projects were successfully completed. 48 refs., 12 figs., 2 tabs.

  17. Effects of a 60 Hz magnetic field on central cholinergic systems of the rat

    SciTech Connect

    Lai, H.; Carino, M.A.; Horita, A.; Guy, A.W. )

    1993-03-15

    The authors studied the effects of an acute exposure to a 60 Hz magnetic field on sodium-dependent, high-affinity choline uptake in the brain of the rat. Decreases in uptake were observed in the frontal cortex and hippocampus after the animals were exposed to a magnetic field at flux densities [>=] 0.75 mT. These effects of the magnetic field were blocked by pretreating the animals with the narcotic antagonist naltrexone, but not by the peripheral opioid antagonist, naloxone methiodide. These data indicate that the magnetic-field-induced decreases in high-affinity choline uptake in the rat brain were mediated by endogenous opioids in the central nervous systems.

  18. All-weather ultraviolet solar spectra retrieved at a 0.5-Hz sampling rate.

    PubMed

    Thorseth, T M; Kjeldstad, B

    1999-10-20

    A measurement scheme and an algorithm have been developed to retrieve global irradiance ultraviolet solar spectra (290-400 nm) at a sampling rate of 0.5 Hz. The algorithm combines spectral irradiance measurements performed with a slow (a few minutes) scanning spectroradiometer (Optronic Model OL752) and a moderate bandwidth multichannel radiometer (Biospherical ground-based ultraviolet radiometer Model 541). The filter radiometer instrument allows for continuous observations of global UV radiation at five channels (approximately 10-nm bandwidth), performed simultaneously with spectral measurements. Information about changing cloud conditions during a spectral scan was retrieved from filter measurements and applied to spectral data, hence estimated spectra without cloud variations could be constructed. The quality of the estimated spectra depends on data quality from both instruments. The method works well in all kinds of weather conditions, as long as the Sun is above the horizon and none of the instruments are hampered by measurement errors. PMID:18324148

  19. Effect of chronic 60-Hz electric field exposure on mammary tumorigenesis in the rat

    SciTech Connect

    Anderson, L.E.; Leung, F.C.; Rommereim, D.N.; Buschbom, R.L.; Wilson, B.W.; Stevens, R.G.

    1989-07-01

    Female rats were administered a single dosage of 7 or 10 mg of DMBA intragastrically between 50 and 55 days of age and palpated weekly for mammary tumors in two experiments. Rats were either exposed to a 40 kV/m 60-Hz electric field or sham-exposed in utero through 18 or 23 weeks of age. There was no difference between electric field exposed and sham-exposed in incidence of first tumor. When the results of the two experiments were combined, the electric field exposed groups had significantly more tumors per tumor-bearing animal than the sham-groups. These results may have implications for the role of electric power use in the etiology and promotion of breast cancer. 21 refs., 1 fig., 1 tab.

  20. Exposure to high-frequency electromagnetic fields (100 kHz-2 GHz) in Extremadura (Spain).

    PubMed

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

    2011-12-01

    The last decade has seen a rapid increase in people's exposure to electromagnetic fields. This paper reports the measurements of radiofrequency (RF) total power densities and power density spectra in 35 towns of the region of Extremadura, Spain. The spectra were taken with three antennas covering frequencies from 100 kHz to 2.2 GHz. This frequency range includes AM/FM radio broadcasting, television, and cellular telephone signals. The power density data and transmitting antenna locations were stored in a geographic information system (GIS) as an aid in analyzing and interpreting the results. The results showed the power density levels to be below the reference level guidelines for human exposure and that the power densities are different for different frequency ranges and different size categories of towns. PMID:22048492

  1. Strain development during the phase transition of La(Fe,Mn,Si)13Hz

    NASA Astrophysics Data System (ADS)

    Neves Bez, Henrique; Nielsen, Kaspar K.; Smith, Anders; Norby, Poul; Stâhl, Kenny; Bahl, Christian R. H.

    2016-08-01

    We use powder X-ray diffraction to evaluate the temperature dependence of the crystalline properties during the magnetic phase transition of La(Fe,Mn,Si)13Hz as a function of the Fe/Mn/Si ratio. Both the paramagnetic and ferromagnetic phases were observed as peak overlaps in the patterns around the Curie temperature (TC) occurring continuously in a temperature range of about 5 K around TC. Using the Williamson-Hall method, we evaluate the strain developing in the crystallites during the transition and find that it is associated with the growth of the paramagnetic phase as the transition occurs. Based on our measurements and microstructure analyses, we propose that cracking during the phase transition is due to or aggravated by the small content of a La-rich phase.

  2. A stroll with eLISA through the mHz gravitational-wave zoo

    NASA Astrophysics Data System (ADS)

    Littenberg, Tyson

    2013-04-01

    No great scientific endeavor has been without setbacks, and space-based gravitational wave (GW) astronomy has seen its fair share. Despite programmatic challenges, the science-case for a gravitational wave observatory operating in the mHz regime has never been stronger. Improvements in both theoretical understanding of the sources, and advancements in techniques for extracting signals from the data, have allowed the anticipated science impact of a space borne detector to survive imposed reductions in mission scope. I will lay out the case for the GW sources which we predict will play a starring role in the eLISA/NGO source catalog, and highlight how inferences made from these systems will help answer pressing questions in both physics and astronomy.

  3. Single-beam Denisyuk holograms recording with pulsed 30Hz RGB laser

    NASA Astrophysics Data System (ADS)

    Zacharovas, Stanislovas; Bakanas, Ramūnas; Stankauskas, Algimantas

    2016-03-01

    It is well known fact that holograms can be recorded either by continuous wave (CW) laser, or by single pulse coming from pulsed laser. However, multi-pulse or multiple-exposure holograms were used only in interferometry as well as for information storage. We have used Geola's single longitudinal mode pulsed RGB laser to record Denisyuk type holograms. We successfully recorded objects situated at the distance of more than 30cm, employing the multi-pulse working regime of the laser. To record Denisyuk hologram we have used 50 ns duration 440, 660nm wavelength and 35ns duration 532nm wavelength laser pulses at the repetition rate of 30Hz. As photosensitive medium we have used Slavich-Geola PFG-03C glass photoplate. Radiations with different wavelengths were mixed into "white" beam, collimated and directed onto the photoplate. For further objects illumination an additional flat silver coated mirror was used.

  4. Three-dimensional magnetic cloak working from d.c. to 250 kHz

    PubMed Central

    Zhu, Jianfei; Jiang, Wei; Liu, Yichao; Yin, Ge; Yuan, Jun; He, Sailing; Ma, Yungui

    2015-01-01

    Invisible cloaking is one of the major outcomes of the metamaterial research, but the practical potential, in particular for high frequencies (for example, microwave to visible light), is fatally challenged by the complex material properties they usually demand. On the other hand, it will be advantageous and also technologically instrumental to design cloaking devices for applications at low frequencies where electromagnetic components are favourably uncoupled. In this work, we vastly develop the bilayer approach to create a three-dimensional magnetic cloak able to work in both static and dynamic fields. Under the quasi-static approximation, we demonstrate a perfect magnetic cloaking device with a large frequency band from 0 to 250 kHz. The practical potential of our device is experimentally verified by using a commercial metal detector, which may lead us to having a real cloaking application where the dynamic magnetic field can be manipulated in desired ways. PMID:26596641

  5. 100-kHz 22-fs Ti:sapphire regenerative amplification laser with programmable spectral control

    NASA Astrophysics Data System (ADS)

    Sung, Jae Hee; Lee, Hwang Woon; Nam, Chang Hee; Lee, Seong Ku

    2016-05-01

    An ultrashort, high-power Ti:sapphire laser operating at 100 kHz was developed. A regenerative amplifier with a cryogenically cooled Ti:sapphire crystal and a grism compressor were incorporated in the laser. For achieving a wide bandwidth of 78 nm, a programmable spectral control filter was applied to the regenerative amplifier to compensate for the gain narrowing effect. An output power of 1.4 GW with near Fourier-transform-limited pulse duration of 22 fs was achieved after minimizing a spectral phase error with the grism compressor, and the measured beam quality factor ( M 2) was less than 1.2. This high-quality laser will facilitate applications requiring high-repetition rate, ultrashort, high-power laser pulses.

  6. Three-dimensional magnetic cloak working from d.c. to 250 kHz

    NASA Astrophysics Data System (ADS)

    Zhu, Jianfei; Jiang, Wei; Liu, Yichao; Yin, Ge; Yuan, Jun; He, Sailing; Ma, Yungui

    2015-11-01

    Invisible cloaking is one of the major outcomes of the metamaterial research, but the practical potential, in particular for high frequencies (for example, microwave to visible light), is fatally challenged by the complex material properties they usually demand. On the other hand, it will be advantageous and also technologically instrumental to design cloaking devices for applications at low frequencies where electromagnetic components are favourably uncoupled. In this work, we vastly develop the bilayer approach to create a three-dimensional magnetic cloak able to work in both static and dynamic fields. Under the quasi-static approximation, we demonstrate a perfect magnetic cloaking device with a large frequency band from 0 to 250 kHz. The practical potential of our device is experimentally verified by using a commercial metal detector, which may lead us to having a real cloaking application where the dynamic magnetic field can be manipulated in desired ways.

  7. Band limited emission with central frequency around 2 Hz accompanying powerful cyclones

    NASA Technical Reports Server (NTRS)

    Troitskaia, V. A.; Shepetnov, K. S.; Dvobnia, B. D.

    1992-01-01

    It has been found that powerful cyclones are proceeded, accompanied and followed by narrow band electromagnetic emission with central frequency around 2 Hz. It is shown that the signal from this emission is unique and clearly distinguishable from known types of magnetic pulsations, spectra of local thunderstorms, and signals from industrial sources. This emission was first observed during an unusually powerful cyclone with tornadoes in the western European part of the Soviet Union, which passed by the observatory of Borok from south to north-east. The emission has been confirmed by analysis of similar events in Antarctica. The phenomenon described presents a new aspect of interactions of processes in the lower atmosphere and the ionosphere.

  8. 0.26-Hz-linewidth ultrastable lasers at 1557 nm

    PubMed Central

    Wu, Lifei; Jiang, Yanyi; Ma, Chaoqun; Qi, Wen; Yu, Hongfu; Bi, Zhiyi; Ma, Longsheng

    2016-01-01

    Narrow-linewidth ultrastable lasers at 1.5 μm are essential in many applications such as coherent transfer of light through fiber and precision spectroscopy. Those applications all rely on the ultimate performance of the lasers. Here we demonstrate two ultrastable lasers at 1557 nm with a most probable linewidth of 0.26 Hz by independently frequency-stabilizing to the resonance of 10-cm-long ultrastable Fabry-Pérot cavities at room temperature. The fractional frequency instability of each laser system is nearly 8 × 10−16 at 1–30 s averaging time, approaching the thermal noise limit of the reference cavities. A remarkable frequency instability of 1 × 10−15 is achieved on the long time scale of 100–4000 s. PMID:27117356

  9. 0.26-Hz-linewidth ultrastable lasers at 1557 nm.

    PubMed

    Wu, Lifei; Jiang, Yanyi; Ma, Chaoqun; Qi, Wen; Yu, Hongfu; Bi, Zhiyi; Ma, Longsheng

    2016-01-01

    Narrow-linewidth ultrastable lasers at 1.5 μm are essential in many applications such as coherent transfer of light through fiber and precision spectroscopy. Those applications all rely on the ultimate performance of the lasers. Here we demonstrate two ultrastable lasers at 1557 nm with a most probable linewidth of 0.26 Hz by independently frequency-stabilizing to the resonance of 10-cm-long ultrastable Fabry-Pérot cavities at room temperature. The fractional frequency instability of each laser system is nearly 8 × 10(-16) at 1-30 s averaging time, approaching the thermal noise limit of the reference cavities. A remarkable frequency instability of 1 × 10(-15) is achieved on the long time scale of 100-4000 s. PMID:27117356

  10. 0.26-Hz-linewidth ultrastable lasers at 1557 nm

    NASA Astrophysics Data System (ADS)

    Wu, Lifei; Jiang, Yanyi; Ma, Chaoqun; Qi, Wen; Yu, Hongfu; Bi, Zhiyi; Ma, Longsheng

    2016-04-01

    Narrow-linewidth ultrastable lasers at 1.5 μm are essential in many applications such as coherent transfer of light through fiber and precision spectroscopy. Those applications all rely on the ultimate performance of the lasers. Here we demonstrate two ultrastable lasers at 1557 nm with a most probable linewidth of 0.26 Hz by independently frequency-stabilizing to the resonance of 10-cm-long ultrastable Fabry-Pérot cavities at room temperature. The fractional frequency instability of each laser system is nearly 8 × 10‑16 at 1–30 s averaging time, approaching the thermal noise limit of the reference cavities. A remarkable frequency instability of 1 × 10‑15 is achieved on the long time scale of 100–4000 s.

  11. Direct welding of glass and metal by 1  kHz femtosecond laser pulses.

    PubMed

    Zhang, Guodong; Cheng, Guanghua

    2015-10-20

    In the welding process between similar or dissimilar materials, inserting an intermediate layer and pressure assistance are usually thought to be necessary. In this paper, the direct welding between alumina-silicate glass and metal (aluminum, copper, and steel), under exposure from 1 kHz femtosecond laser pulses without any auxiliary processes, is demonstrated. The micron/nanometer-sized metal particles induced by laser ablation were considered to act as the adhesive in the welding process. The welding parameters were optimized by varying the pulse energy and the translation velocity of the sample. The shear joining strength characterized by a shear force testing equipment was as high as 2.34 MPa. This direct bonding technology has potential for applications in medical devices, sensors, and photovoltaic devices. PMID:26560385

  12. Mechanism for generation of 2-3 kHz radiation in the outer heliosphere

    NASA Technical Reports Server (NTRS)

    Macek, W. M.

    1995-01-01

    The question of how low-frequency non-thermal radio emissions at the boundary of the heliosphere might be generated is considered. The mechanism consists of two steps. First, the beam of energetic electrons generates a high level of electrostatic Langmuir plasma waves. Second, electromagnetic radiation results from the non-linear interaction between Langmuir waves. Intensity of radio emissions at 2 to 3 kHz detected by the Voyager plasma wave instrument in the outer heliosphere can be explained provided that the electron beams generating Langmuir waves exist also in the postshock plasma due to secondary shocks in the compressed solar wind beyond the termination shock. Modification of the heliospheric shocks by the cosmic ray pressure is also taken into account. The field strengths of Langmuir waves required to generate the second harmonic emissions are of 50 to 100 microvolts per meter. These waves may be observed in situ by Voyager 1 and 2 in the near future.

  13. The gravitational resolving power of global seismic networks in the 0.1-10 Hz band

    NASA Astrophysics Data System (ADS)

    Mulargia, Francesco; Kamenshchik, Alexander

    2016-04-01

    Among the first attempts to detect gravitational waves, the seismic approach pre-dates the digital era. Major advances in computational power, seismic instrumentation and in the knowledge of seismic noise suggest to reappraise its potential. Using the whole earth as a detector, with the thousands of digital seismometers of seismic global networks as a single phased array, more than two decades of continuous seismic noise data are available and can be readily sifted at the only cost of (a pretty gigantic) computation. Using a subset of data, we show that absolute strains h ≲10-17 on burst gravitational pulses and h ≲10-21 on periodic signals may be feasibly resolved in the frequency range 0.1-10 Hz, only marginally covered by current advanced LIGO and future eLISA. However, theoretical predictions for the largest cosmic gravitational emissions at these frequencies are a few orders of magnitude lower.

  14. Photoreactivation and dark repair of environmental E. coli strains following 24 kHz continuous ultrasound and UV-C irradiation.

    PubMed

    Kaur, Jasjeet; Karthikeyan, Raghupathy; Pillai, Suresh D

    2016-07-01

    In this study, effects of 24 kHz continuous ultrasound and UV-C on inactivation and potential repair of environmental E. coli strains were studied through a culture based method and a metabolic activity assay. Three environmental E. coli strains isolated from fecal samples of feral hog and deer and treated wastewater effluent were studied and compared with a laboratory E. coli strain (ATCC® 10798). Metabolic activity of E. coli cells during the inactivation and repair period was assessed using the AlamarBlue® assay. Transmission electron microscopy assays were also performed to evaluate morphological damage of bacterial cell wall. After 24 h of photoreactivation period, laboratory E. coli strain (ATCC® 10798) reactivated by 30% and 42% in contrast to E. coli isolate from treated wastewater effluent, which reactivated by 53% and 82% after ultrasound and UV-C treatment, respectively. Possible shearing and reduction in cell size of E. coli strains exposed to ultrasound was revealed by transmission electron micrographs. Metabolic activity of E. coli strains was greatly reduced due to morphological damage to cell membrane caused by 24 kHz continuous ultrasound. Based upon experimental data and TEM micrographs, it could be concluded that ultrasound irradiation has potential in advanced water treatment and water reuse applications. PMID:27050143

  15. Photoreactivation and dark repair of environmental E. coli strains following 24 kHz continuous ultrasound and UV-C irradiation.

    PubMed

    Kaur, Jasjeet; Karthikeyan, Raghupathy; Pillai, Suresh D

    2016-07-01

    In this study, effects of 24 kHz continuous ultrasound and UV-C on inactivation and potential repair of environmental E. coli strains were studied through a culture based method and a metabolic activity assay. Three environmental E. coli strains isolated from fecal samples of feral hog and deer and treated wastewater effluent were studied and compared with a laboratory E. coli strain (ATCC® 10798). Metabolic activity of E. coli cells during the inactivation and repair period was assessed using the AlamarBlue® assay. Transmission electron microscopy assays were also performed to evaluate morphological damage of bacterial cell wall. After 24 h of photoreactivation period, laboratory E. coli strain (ATCC® 10798) reactivated by 30% and 42% in contrast to E. coli isolate from treated wastewater effluent, which reactivated by 53% and 82% after ultrasound and UV-C treatment, respectively. Possible shearing and reduction in cell size of E. coli strains exposed to ultrasound was revealed by transmission electron micrographs. Metabolic activity of E. coli strains was greatly reduced due to morphological damage to cell membrane caused by 24 kHz continuous ultrasound. Based upon experimental data and TEM micrographs, it could be concluded that ultrasound irradiation has potential in advanced water treatment and water reuse applications.

  16. 486nm blue laser operating at 500 kHz pulse repetition frequency

    NASA Astrophysics Data System (ADS)

    Creeden, Daniel; Blanchard, Jon; Pretorius, Herman; Limongelli, Julia; Setzler, Scott D.

    2016-03-01

    Compact, high power blue light in the 470-490nm region is difficult to generate due to the lack of laser sources which are easily convertible (through parametric processes) to those wavelengths. By using a pulsed Tm-doped fiber laser as a pump source for a 2-stage second harmonic generation (SHG) scheme, we have generated ~2W of 486.5nm light at 500kHz pulse repetition frequency (PRF). To our knowledge, this is the highest PRF and output power achieved in the blue region based on a frequency converted, monolithic fiber laser. This pump laser is a pulsed Tm-doped fiber laser/amplifier which generates 12.8W of 1946nm power at 500kHz PRF with diffraction-limited output from a purely single-mode fiber. The output from this laser is converted to 973nm through second harmonic generation (SHG). The 973nm is then converted to 486.5nm via another SHG stage. This architecture operates with very low peak power, which can be challenging from a nonlinear conversion standpoint. However, the low peak power enables the use of a single-mode monolithic fiber amplifier without undergoing nonlinear effects in the fiber. This also eliminates the need for novel fiber designs, large-mode area fiber, or free-space coupling to rod-type amplifiers, improving reliability and robustness of the laser source. Higher power and conversion efficiency are possible through the addition of Tm-doped fiber amplification stages as well as optimization of the nonlinear conversion process and nonlinear materials. In this paper, we discuss the laser layout, results, and challenges with generating blue light using a low peak power approach.

  17. Acute exposure to 50-Hz magnetic fields increases interleukin-6 in young healthy men.

    PubMed

    Selmaoui, Brahim; Lambrozo, Jacques; Sackett-Lundeen, Linda; Haus, Erhard; Touitou, Yvan

    2011-12-01

    Some epidemiologic studies have suggested that extremely low frequency magnetic fields might affect human health and, in particular, that the incidence of certain types of cancer might increase among individuals living or working in environments exposed to such fields. This study is part of a broad study we conducted in humans. The study presented here was designed to look for possible effects of acute exposure to 50-Hz magnetic fields (10 μT) on the interleukin 1 beta (IL-1β), interleukin 2 (IL-2), interleukin 6 (IL-6), interleukin-1 receptor antagonist (IL-1RA), and the interleukin-2 receptor (IL-2R) production. Thirty-two young men (20-30 years old) were divided into two groups (sham-exposed or control group and exposed group) of 16 subjects each. All subjects participated in two 24-h experiments to evaluate the effects of both continuous and intermittent (1 h "off" and 1 h "on" with the field switched "on" and "off" every 15 s) exposure to linearly polarized magnetic fields. The subjects were exposed to the magnetic field from 2300 to 0800 while recumbent. Blood samples were collected during each session at 11:00, 17:00, 22:00, 01:00, 04:00, 06:00, and 08:00. Results showed that exposure to 50-Hz magnetic fields (10 μT) significantly increases IL-6 when subjects were exposed to an intermittent magnetic field. However, no effect has been observed on interleukin IL-1β, IL-2, IL-1RA, and IL-2R.

  18. Exercise reward induces appetitive 50-kHz calls in rats.

    PubMed

    Heyse, Natalie C; Brenes, Juan C; Schwarting, Rainer K W

    2015-08-01

    Rats express affective states by visible behaviors (like approach or flight) and through different kinds of ultrasonic vocalizations (USV). 50-kHz calls are thought to reflect positive affective states since they occur during rewarding situations like social play or palatable food. However, the effects of voluntary exercise on USV have not been investigated yet, although such exercise can serve as reward. To this aim, we gave young adult rats restricted daily access to a runway maze, where they could interact with either a movable (experimental group) or locked wheel (sedentary group) for 14days and we tested USV in anticipation of and during subsequent running. We also studied inter-individual differences in running, and relationships with USV, and rat-typical trait measures. The results showed that the experimental rats had to be separated into "runners" and "pseudorunners" since only runners performed true running, whereas pseudorunners hardly entered the wheel and turned it only with their forelimbs. This outcome seems to be related to subject-dependent differences in responding to novelty and in reward sensitivity, as indicated by pertinent screening tests, which we had performed prior to the 14days of wheel access. In the runway, our experimental and control groups did not differ in visible anticipatory behavior, like approach. Yet, only runners and sedentary rats displayed an increasing but similar amount of anticipatory USV, which is suggestive of a state of incentive anticipation of the coming wheel access. During exercise, only runners increased USV, probably indicating a highly positive emotional state. To conclude, voluntary exercise provides a promising tool to induce 50-kHz USV during and in anticipation of exercise. When performing such studies, possible individual differences between subjects have to be taken into account, and the actual wheel performance should carefully be controlled. PMID:25872156

  19. Tickling increases dopamine release in the nucleus accumbens and 50 kHz ultrasonic vocalizations in adolescent rats.

    PubMed

    Hori, Miyo; Shimoju, Rie; Tokunaga, Ryota; Ohkubo, Masato; Miyabe, Shigeki; Ohnishi, Junji; Murakami, Kazuo; Kurosawa, Mieko

    2013-03-27

    Adolescent rats emit 50 kHz ultrasonic vocalizations, a marker of positive emotion, during rough-and-tumble play or on tickling stimulation. The emission of 50 kHz ultrasonic vocalizations in response to tickling is suggested to be mediated by dopamine release in the nucleus accumbens; however, there is no direct evidence supporting this hypothesis. The present study aimed to elucidate whether play behavior (tickling) in adolescent rats can trigger dopamine release in the nucleus accumbens with hedonic 50 kHz ultrasonic vocalizations. The effect of tickling stimulation was compared with light-touch stimulation, as a discernible stimulus. We examined 35-40-day-old rats, which corresponds to the period of midadolescence. Tickling stimulation for 5 min significantly increased dopamine release in the nucleus accumbens (118±7% of the prestimulus control value). Conversely, light-touch stimulation for 5 min did not significantly change dopamine release. In addition, 50 kHz ultrasonic vocalizations were emitted during tickling stimulation but not during light-touch stimulation. Further, tickling-induced 50 kHz ultrasonic vocalizations were significantly blocked by the direct application of SCH23390 (D1 receptor antagonist) and raclopride (D2/D3 receptor antagonist) into the nucleus accumbens. Our study demonstrates that tickling stimulation in adolescent rats increases dopamine release in the nucleus accumbens, leading to the generation of 50 kHz ultrasonic vocalizations.

  20. Pre-Synaptic Inhibition of Afferent Feedback in the Macaque Spinal Cord Does Not Modulate with Cycles of Peripheral Oscillations Around 10 Hz

    PubMed Central

    Galán, Ferran; Baker, Stuart N.

    2015-01-01

    Spinal interneurons are partially phase-locked to physiological tremor around 10 Hz. The phase of spinal interneuron activity is approximately opposite to descending drive to motoneurons, leading to partial phase cancellation and tremor reduction. Pre-synaptic inhibition of afferent feedback modulates during voluntary movements, but it is not known whether it tracks more rapid fluctuations in motor output such as during tremor. In this study, dorsal root potentials (DRPs) were recorded from the C8 and T1 roots in two macaque monkeys following intra-spinal micro-stimulation (random inter-stimulus interval 1.5–2.5 s, 30–100 μA), whilst the animals performed an index finger flexion task which elicited peripheral oscillations around 10 Hz. Forty one responses were identified with latency < 5 ms; these were narrow (mean width 0.59 ms), and likely resulted from antidromic activation of afferents following stimulation near terminals. Significant modulation during task performance occurred in 16/41 responses, reflecting terminal excitability changes generated by pre-synaptic inhibition (Wall's excitability test). Stimuli falling during large-amplitude 8–12 Hz oscillations in finger acceleration were extracted, and sub-averages of DRPs constructed for stimuli delivered at different oscillation phases. Although some apparent phase-dependent modulation was seen, this was not above the level expected by chance. We conclude that, although terminal excitability reflecting pre-synaptic inhibition of afferents modulates over the timescale of a voluntary movement, it does not follow more rapid changes in motor output. This suggests that pre-synaptic inhibition is not part of the spinal systems for tremor reduction described previously, and that it plays a role in overall—but not moment-by-moment—regulation of feedback gain. PMID:26635536

  1. Analysis of the effect of a 60 Hz AC field on histamine release by rat peritoneal mast cells.

    PubMed

    Price, J A; Strattan, R D

    1998-01-01

    Reports have indicated effects of electromagnetic fields on inflammatory processes in vivo. To begin a systematic approach toward separating and examining the many components of such responses, we created and tested a temperature-controlled device to develop 5 mT 60 Hz magnetic fields for studies of the effects of fields on mast cells, a key component in acute inflammatory responses. Such fields have been reported to modulate cell activity, including changes in membrane function, in various systems. The magnetic field was generated using a solenoid and calibrated with an induction probe. Tests of mast cell function were determined by histamine release response to stimulation by compound 48/80, using both an "expose then test" and a "test during exposure" protocol. Aliquots not treated with 48/80 were used to evaluate field treatment effects on spontaneous histamine release. Freshly harvested rat peritoneal mast cells were exposed to the magnetic field for periods of 30 min to 2 h at 37 degrees C. They showed no significant degranulation during treatment, nor did they show reduced sensitivity to the degranulating agent 48/80. These observations are consistent with a model in which such processes are exclusively reflexive by the cells using field-independent membrane systems. This observation is very useful and was needed before examining longer term exposures in which gene expression in the cells might be influenced; this is the first such report of in vitro exposure of purified mast cells under these conditions and will further the study of the effects of electromagnetic fields on cell types active in acute inflammation.

  2. The Effects of Electrical and Optical Stimulation of Midbrain Dopaminergic Neurons on Rat 50-kHz Ultrasonic Vocalizations

    PubMed Central

    Scardochio, Tina; Trujillo-Pisanty, Ivan; Conover, Kent; Shizgal, Peter; Clarke, Paul B. S.

    2015-01-01

    Rationale: Adult rats emit ultrasonic vocalizations (USVs) at around 50-kHz; these commonly occur in contexts that putatively engender positive affect. While several reports indicate that dopaminergic (DAergic) transmission plays a role in the emission of 50-kHz calls, the pharmacological evidence is mixed. Different modes of dopamine (DA) release (i.e., tonic and phasic) could potentially explain this discrepancy. Objective: To investigate the potential role of phasic DA release in 50-kHz call emission. Methods: In Experiment 1, USVs were recorded in adult male rats following unexpected electrical stimulation of the medial forebrain bundle (MFB). In parallel, phasic DA release in the nucleus accumbens (NAcc) was recorded using fast-scan cyclic voltammetry. In Experiment 2, USVs were recorded following response-contingent or non-contingent optogenetic stimulation of midbrain DAergic neurons. Four 20-s schedules of optogenetic stimulation were used: fixed-interval, fixed-time, variable-interval, and variable-time. Results: Brief electrical stimulation of the MFB increased both 50-kHz call rate and phasic DA release in the NAcc. During optogenetic stimulation sessions, rats initially called at a high rate comparable to that observed following reinforcers such as psychostimulants. Although optogenetic stimulation maintained reinforced responding throughout the 2-h session, the call rate declined to near zero within the first 30 min. The trill call subtype predominated following both electrical and optical stimulation. Conclusion: The occurrence of electrically-evoked 50-kHz calls, time-locked to phasic DA (Experiment 1), provides correlational evidence supporting a role for phasic DA in USV production. However, in Experiment 2, the temporal dissociation between calling and optogenetic stimulation of midbrain DAergic neurons suggests that phasic mesolimbic DA release is not sufficient to produce 50-kHz calls. The emission of the trill subtype of 50-kHz calls

  3. Absence of DNA damage after 60-Hz electromagnetic field exposure combined with ionizing radiation, hydrogen peroxide, or c-Myc overexpression.

    PubMed

    Jin, Yeung Bae; Choi, Seo-Hyun; Lee, Jae Seon; Kim, Jae-Kyung; Lee, Ju-Woon; Hong, Seung-Cheol; Myung, Sung Ho; Lee, Yun-Sil

    2014-03-01

    The principal objective of this study was to assess the DNA damage in a normal cell line system after exposure to 60 Hz of extremely low frequency magnetic field (ELF-MF) and particularly in combination with various external factors, via comet assays. NIH3T3 mouse fibroblast cells, WI-38 human lung fibroblast cells, L132 human lung epithelial cells, and MCF10A human mammary gland epithelial cells were exposed for 4 or 16 h to a 60-Hz, 1 mT uniform magnetic field in the presence or absence of ionizing radiation (IR, 1 Gy), H(2)O(2) (50 μM), or c-Myc oncogenic activation. The results obtained showed no significant differences between the cells exposed to ELF-MF alone and the unexposed cells. Moreover, no synergistic or additive effects were observed after 4 or 16 h of pre-exposure to 1 mT ELF-MF or simultaneous exposure to ELF-MF combined with IR, H(2)O(2), or c-Myc activation.

  4. Exotic decays of a heavy neutral Higgs through HZ/AZ channel

    NASA Astrophysics Data System (ADS)

    Coleppa, Baradhwaj; Kling, Felix; Su, Shufang

    2014-09-01

    Models of electroweak symmetry breaking with extended Higgs sectors are theoretically well motivated. In this study, we focus on the Two Higgs Doublet Model with a low energy spectrum containing scalars H and a pseudoscalar A. We study the decays A → HZ or H → AZ, which could reach sizable branching fractions in certain parameter regions. With detailed collider analysis, we obtain model independent exclusion bounds as well as discovery reach at the 14 TeV LHC for the process: gg → A/ H → HZ/ AZ, looking at final states bbℓℓ, ττℓℓ and ZZZ(4 ℓ + 2 j) for ℓ = e, μ. We further interpret these bounds in the context of the Type II Two Higgs Doublet Model, considering three different classes of processes: A → h 0 Z, A → H 0 Z, and H 0 → AZ, in which h 0 and H 0 are the light and heavy CP-even Higgses respectively. For 100 fb-1 integrated luminosity at the 14 TeV LHC, we find that for parent particle mass around 300-400 GeV, A → h 0 Z has the greatest reach when H 0 is interpreted as the 126 GeV Higgs: most regions in the tan β versus sin( β - α) plane can be excluded and a significant fraction at small and large tan β can be covered by discovery. For 126 GeV h 0, only relatively small tan β ≲ 10 (5) can be reached by exclusion (discovery) while a wide range of sin( β - α) is accessible. For A → H 0 Z, the reach is typically restricted to sin( β - α) ~ ±1 with tan β ≲ 10 in bbℓℓ and ττℓℓ channels. The ZZZ(4 ℓ2 j) channel, on the other hand, covers a wide range of 0 .3 < | sin( β - α)| < 1 for tan β ≲ 4. H 0 → AZ typically favors negative values of sin( β - α), with exclusion/discovery reach possibly extending to all values of tan β. A study of exotic decays of extra Higgses appearing in extensions of the Standard Model would extend the reach at the LHC and provides nice complementarity to conventional Higgs search channels.

  5. Synergistic effects of noradrenergic modulation with atomoxetine and 10 Hz repetitive transcranial magnetic stimulation on motor learning in healthy humans

    PubMed Central

    2014-01-01

    Background Repetitive transcranial magnetic stimulation (rTMS) is able to induce changes in neuronal activity that outlast stimulation. The underlying mechanisms are not completely understood. They might be analogous to long-term potentiation or depression, as the duration of the effects seems to implicate changes in synaptic plasticity. Norepinephrine (NE) has been shown to play a crucial role in neuronal plasticity in the healthy and injured human brain. Atomoxetine (ATX) and other NE reuptake inhibitors have been shown to increase excitability in different systems and to influence learning processes. Thus, the combination of two facilitative interventions may lead to further increase in excitability and motor learning. But in some cases homeostatic metaplasticity might protect the brain from harmful hyperexcitability. In this study, the combination of 60 mg ATX and 10 Hz rTMS over the primary motor cortex was used to examine changes in cortical excitability and motor learning and to investigate their influence on synaptic plasticity mechanisms. Results The results of this double-blind placebo-controlled study showed that ATX facilitated corticospinal and intracortical excitability in motor cortex. 10 Hertz rTMS applied during a motor task was able to further increase intracortical excitability only in combination with ATX. In addition, only the combination of 10 Hz rTMS and ATX was capable of enhancing the total number of correct responses and reaction time significantly, indicating an interaction effect between rTMS and ATX without signs of homeostatic metaplasticity. Conclusion These results suggest that pharmacologically enhanced NE transmission and 10 Hz rTMS exert a synergistic effect on motor cortex excitability and motor learning in healthy humans. PMID:24690416

  6. A broadband, capacitive, surface-micromachined, omnidirectional microphone with more than 200 kHz bandwidth.

    PubMed

    Kuntzman, Michael L; Hall, Neal A

    2014-06-01

    A surface micromachined microphone is presented with 230 kHz bandwidth. The structure uses a 2.25 μm thick, 315 μm radius polysilicon diaphragm suspended above an 11 μm gap to form a variable parallel-plate capacitance. The back cavity of the microphone consists of the 11 μm thick air volume immediately behind the moving diaphragm and also an extended lateral cavity with a radius of 504 μm. The dynamic frequency response of the sensor in response to electrostatic signals is presented using laser Doppler vibrometry and indicates a system compliance of 0.4 nm/Pa in the flat-band of the response. The sensor is configured for acoustic signal detection using a charge amplifier, and signal-to-noise ratio measurements and simulations are presented. A resolution of 0.80 mPa/√Hz (32 dB sound pressure level in a 1 Hz bin) is achieved in the flat-band portion of the response extending from 10 kHz to 230 kHz. The proposed sensor design is motivated by defense and intelligence gathering applications that require broadband, airborne signal detection.

  7. Frequency-modulated 50 kHz ultrasonic vocalizations: a tool for uncovering the molecular substrates of positive affect.

    PubMed

    Burgdorf, Jeffrey; Panksepp, Jaak; Moskal, Joseph R

    2011-10-01

    The evidence that frequency modulated (FM) 50 kHz ultrasonic vocalizations (USVs) reflect a positive emotional state in rats is reviewed. Positive emotional states in humans are measured by facial-vocal displays (e.g., Duchenne smiling and laughter), approach behavior, and subjective self-report of feeling states. In laboratory animals, only facial-vocal displays, along with approach behavior can be measured. FM 50 kHz USVs are uniquely elevated by hedonic stimuli and suppressed by aversive stimuli. Rates of FM 50 kHz USVs are positively correlated to the rewarding value of the eliciting stimulus. Additionally, playbacks of these vocalizations are rewarding. The neural and pharmacological substrates of 50 kHz USVs are consistent with those of human positive affective states. By experimentally eliciting FM 50 kHz USVs, the novel molecular underpinning of positive affect can be elucidated and may be similar to those in humans. In humans, positive emotional states confer resilience to depression and anxiety, as well as promote overall health. Using rough-and-tumble play induced hedonic USVs, we have identified insulin like growth factor I and the NR2B subunit of the NMDA receptor as playing a functional role in positive affective states. From this research, we have developed a promising new class of antidepressants that is entering phase II clinical trials for the treatment of depression. PMID:21144859

  8. The power-law and linear correlations between the twin kHz QPO frequencies in LMXBs

    NASA Astrophysics Data System (ADS)

    Yin, H. X.; Zhao, Y. H.

    After the launch of the Rossi X-ray Timing Explorer RXTE our knowledge of the aperiodic variability of newtron star NS low mass X-ray binaries LMXBs took a substantial step forward especially initiated by the discovery of the kilohertz quasi-periodic oscillations kHz QPOs in about twenty more NS LMXBs We analyzed the recently updated kHz QPO data in NS LMXBs in order to investigate the different correlations of the twin peak kilohertz quasi-periodic oscillations kHz QPOs in bright Z sources and in the less luminous Atoll sources We fitted the data with a power-law relation nu 1 sim nu 2 b and a linear relation nu 2 sim A nu 1 between the upper and the lower kHz QPOs and find that both relations can fit the data well with small chi 2 values sim 1 The implications of our results for the theoretical models for kHz QPOs are discussed

  9. Temporal integration of interaural-time differences carried by trains of 500-Hz tone bursts

    NASA Astrophysics Data System (ADS)

    Akeroyd, Michael A.

    2001-05-01

    The just-noticeable difference for the interaural time difference (ITD) of a sound generally reduces as its duration is increased [e.g., T. Houtgast and R. Plomp, J. Acoust. Soc. Am. 44, 807-812 (1968); E. Hafter and R. H. Dye, J. Acoust. Soc. Am. 73, 644-651 (1983)]. The rate of this temporal integration is less than would be expected from a simple multiple-looks application of signal detection theory, as though one part of the sound is given greater weighting. The present experiment measured the contributions of the start, middle, or end of a sound to the detectability of its ITD. The stimulus was a 32-pip train of 500-Hz, 10-ms pips, diotic apart from some (2-16) target pips which carried the ITD to be detected and which were placed either at the start, middle, or end of the train. Integration rates were determined from psychometric functions measured using four normal-hearing listeners. The results showed that the rate was least for targets placed at the start or end but larger for targets at the middle. The data can be described using a weighted multiple-looks approach, based on an integration function of approximately 100-ms time constant together with an emphasis of the start, and end, of the sound.

  10. Test-retest reliability of the 40 Hz EEG auditory steady-state response.

    PubMed

    McFadden, Kristina L; Steinmetz, Sarah E; Carroll, Adam M; Simon, Steven T; Wallace, Alissa; Rojas, Donald C

    2014-01-01

    Auditory evoked steady-state responses are increasingly being used as a marker of brain function and dysfunction in various neuropsychiatric disorders, but research investigating the test-retest reliability of this response is lacking. The purpose of this study was to assess the consistency of the auditory steady-state response (ASSR) across sessions. Furthermore, the current study aimed to investigate how the reliability of the ASSR is impacted by stimulus parameters and analysis method employed. The consistency of this response across two sessions spaced approximately 1 week apart was measured in nineteen healthy adults using electroencephalography (EEG). The ASSR was entrained by both 40 Hz amplitude-modulated white noise and click train stimuli. Correlations between sessions were assessed with two separate analytical techniques: a) channel-level analysis across the whole-head array and b) signal-space projection from auditory dipoles. Overall, the ASSR was significantly correlated between sessions 1 and 2 (p<0.05, multiple comparison corrected), suggesting adequate test-retest reliability of this response. The current study also suggests that measures of inter-trial phase coherence may be more reliable between sessions than measures of evoked power. Results were similar between the two analysis methods, but reliability varied depending on the presented stimulus, with click train stimuli producing more consistent responses than white noise stimuli.

  11. Rapid Production of Bose-Einstein Condensates at a 1 Hz Rate

    NASA Astrophysics Data System (ADS)

    Farkas, Daniel; Ramirez-Serrano, Jaime; Salim, Evan

    2013-05-01

    The speed at which Bose-Einstein condensates (BECs) can be produced is a key metric for the performance of ultracold-atom inertial sensors, gravimeters, and magnetometers, where production cycle time of ultracold atoms determines sensor bandwidth. Here, we demonstrate production of 87Rb BECs at rates exceeding 1 Hz. Not only can we create a BEC from a hot vapor in less than one second, but we can continuously repeat the process for several cycles. Such speeds are possible because of the short evaporation times that result when atoms are confined in tight traps. In our case, we magnetically trap atoms with an atom chip that seals the top of one of ColdQuanta's RuBECi®vacuum cells. With RF evaporative cooling sequences as short as 450 ms, we attain nearly pure condensates of 2 × 104 atoms. In the future, the apparatus described here will be integrated into a portable system that houses all of the components needed to produce BECs (e.g. lasers, vacuum, electronics, imaging, etc.) in a volume less than 0.3 m3. This work was supported by the Office of Naval Research (SBIR contract N00014-10-C-0282).

  12. Cochlear nonlinearity between 500 and 8000 Hz in listeners with impaired hearing

    NASA Astrophysics Data System (ADS)

    Lopez-Poveda, Enrique A.; Plack, Christopher J.; Meddis, Ray; Blanco, Jose L.

    2003-10-01

    Cochlear nonlinearity was estimated in listeners with impaired hearing using a forward-masking method. For a fixed low-level probe, the masker level required to mask the probe was measured as a function of the masker-probe interval, to produce a temporal masking curve (TMC). TMCs were measured for probe frequencies from 500 to 8000 Hz, and for masker frequencies from 0.5 to 1.6 times the probe frequency. Unlike what happens for normal-hearing (NH) listeners [Lopez-Poveda et al., J. Acoust. Soc. Am. 113, 951-960 (2003)], TMCs for on-frequency maskers sometimes show a single slope, suggesting linear responses for tones at CF. Sometimes, however, two distinct slopes are visible, suggesting remaining compression. Both patterns are uncorrelated with the absolute threshold and are consistent with selective damage to outer or inner hair cells (IHC), respectively. Remarkably, the slope of the TMCs for very low-frequency maskers is shallower for the impaired ears than for normal ones. This result implies that for NH listeners, the slope of the TMCs for very low-frequency maskers reflects some kind of compression, even at high CFs. It is discussed that this compression is likely to occur at the IHC rather than at the basilar membrane. [Work supported by FIS PI020343, G03/203, and Oticon Spain.

  13. Topological defects and nano-Hz gravitational waves in aligned axion models

    NASA Astrophysics Data System (ADS)

    Higaki, Tetsutaro; Jeong, Kwang Sik; Kitajima, Naoya; Sekiguchi, Toyokazu; Takahashi, Fuminobu

    2016-08-01

    We study the formation and evolution of topological defects in an aligned axion model with multiple Peccei-Quinn scalars, where the QCD axion is realized by a certain combination of the axions with decay constants much smaller than the conventional Peccei-Quinn breaking scale. When the underlying U(1) symmetries are spontaneously broken, the aligned structure in the axion field space exhibits itself as a complicated string-wall network in the real space. We find that the string-wall network likely survives until the QCD phase transition if the number of the Peccei-Quinn scalars is greater than two. The string-wall system collapses during the QCD phase transition, producing a significant amount of gravitational waves in the nano-Hz range at present. The typical decay constant is constrained to be below O(100) TeV by the pulsar timing observations, and the constraint will be improved by a factor of 2 in the future SKA observations.

  14. Time-dependent seafloor acoustic backscatter (10-100 kHz).

    PubMed

    Sternlicht, Daniel D; de Moustier, Christian P

    2003-11-01

    A time-dependent model of the acoustic intensity backscattered by the seafloor is described and compared with data from a calibrated, vertically oriented, echo-sounder operating at 33 and 93 kHz. The model incorporates the characteristics of the echo-sounder and transmitted pulse, and the water column spreading and absorption losses. Scattering from the water-sediment interface is predicted using Helmholtz-Kirchhoff theory, parametrized by the mean grain size, the coherent reflection coefficient, and the strength and exponent of a power-law roughness spectrum. The composite roughness approach of Jackson et al. [J. Acoust. Soc. Am. 79, 1410-1422 (1986)], modified for the finite duration of the transmitted signal, is used to predict backscatter from subbottom inhomogeneities. It depends on the sediment's volume scattering and attenuation coefficients, as well as the interface characteristics governing sound transmission into the sediment. Estimation of model parameters (mean grain size, roughness spectrum strength and exponent, volume scattering coefficient) reveals ambiguous ranges for the two spectral components. Analyses of model outputs and of physical measurements reported in the literature yield practical constraints on roughness spectrum parameter settings appropriate for echo-envelope-based sediment classification procedures.

  15. Time-dependent seafloor acoustic backscatter (10-100 kHz).

    PubMed

    Sternlicht, Daniel D; de Moustier, Christian P

    2003-11-01

    A time-dependent model of the acoustic intensity backscattered by the seafloor is described and compared with data from a calibrated, vertically oriented, echo-sounder operating at 33 and 93 kHz. The model incorporates the characteristics of the echo-sounder and transmitted pulse, and the water column spreading and absorption losses. Scattering from the water-sediment interface is predicted using Helmholtz-Kirchhoff theory, parametrized by the mean grain size, the coherent reflection coefficient, and the strength and exponent of a power-law roughness spectrum. The composite roughness approach of Jackson et al. [J. Acoust. Soc. Am. 79, 1410-1422 (1986)], modified for the finite duration of the transmitted signal, is used to predict backscatter from subbottom inhomogeneities. It depends on the sediment's volume scattering and attenuation coefficients, as well as the interface characteristics governing sound transmission into the sediment. Estimation of model parameters (mean grain size, roughness spectrum strength and exponent, volume scattering coefficient) reveals ambiguous ranges for the two spectral components. Analyses of model outputs and of physical measurements reported in the literature yield practical constraints on roughness spectrum parameter settings appropriate for echo-envelope-based sediment classification procedures. PMID:14650007

  16. Immunological and biochemical effects of 60 Hz electric and magnetic fields in humans

    SciTech Connect

    Fotopoulos, S.S.; Graham, C.

    1985-02-05

    Demand for electric power increased at an annual average rate of 7.5% between 1912 and 1971. In order to meet this demand, utility companies have had to increase both the number and the operating voltages employed in their overhead transmission lines. Public concern has been expressed about possible risks to human health and function arising from exposure to the electric and magnetic fields generated by these lines. The New York State Department of Health (NYSDH) is currently administering a wide-ranging research program to address the above issues. As part of this effort, MRI was funded to perform the first double-blind human study of the effects of exposure to combined 60-Hz electric and magnetic fields. The study focused on measure of human performance physiology and subjective state. The present project into the planned double-blind study. The purpose of Phase 1 was to conduct a comprehensive, screening evaluation of the effects of field exposure on human immunologic hematologic and biochemical parameters. Phase 1 of the current program has now also been completed, and the purpose of this report is to summarize our findings in regard to the effects of field exposure on measures of human immunologic, hematologic and biochemical function. The following sections of this document present the specific aims of the research conducted, the experimental methods and procedures followed, and the statistical analysis performed. The document concludes with a discussion of the findings obtained.

  17. A 2.2-Hz modulation of auroral electrons imposed at the geomagnetic equator

    NASA Astrophysics Data System (ADS)

    Lepine, D. R.; Bryant, D. A.; Hall, D. S.

    1980-07-01

    The direct observation of 2.2-Hz oscillations in the intensities of 4-25 keV electrons producing a pulsating aurora is reported. Electrons were measured by a Petrel sounding rocket launched from Kiruna, Sweden in conjunction with measurements made by the geomagnetically conjugate GEOS 2 satellite. Measured precipitated energy flux variations only amounted to 3% of the energy flux at pulsation maximum, and thus do not permit the confirmation of particle modulations as the source of optical brightness modulations. The oscillations, like the previously observed 1-20 sec pulsations, are found to exhibit a marked velocity dispersion, implying an equatorial origin for both forms of modulation. A comparison of the rocket results with GEOS 2 measurements indicates VLF hiss emissions to be modulated at a frequency close to that of electron intensity oscillations, however isotropic angular distributions observed suggest that low-frequency micropulsations cannot cause auroral pulsations by modulating whistler-mode wave amplitudes which induce variations in the rate of pitch-angle scattering of electrons from the magnetosphere.

  18. Biological effects of 60-Hz electric fields on small and large laboratory animals

    SciTech Connect

    Phillips, R.D.

    1981-01-01

    Rats and mice were exposed to 60-Hz electric fields up to 330 kV/m for durations as long as four months. No significant effects were found in the following major areas: metabolic status and growth; organ and tissue morphology; brain morphology; cardiovascular function; serum chemistry; reproduction; prenatal growth and development; teratology; bone growth; peripheral nerve function; humoral and cell-mediated immunity; susceptibility to viral infection; cell and membrane function; illness/malaise; and cytogenetics. Statistically significant effects of electric field exposures were observed in the following areas: bone fracture repair; neonatal development; neuromuscular function; endocrinology; hematology; neurochemistry; urine volume and chemistry; sympathetic nervous system; behavior. It is likely that many of the effects observed are secondary to chronic stimulation of the animal by the field. Our research efforts have shifted to an in-depth investigation of nervous system functions, with emphasis in behavior, neurochemistry, neurophysiology, and dosimetry. Current and future research in these areas will focus on: relationship of effects to field strength and duration of exposure; recovery from observed effects; fundamental understanding of observed effects; fundamental understanding of interaction of field with animal (dosimetry); and biological significance of observed effects. (ERB)

  19. CFD simulation of a miniature coaxial Stirling-type pulse tube cryocooler operating at 128 Hz

    NASA Astrophysics Data System (ADS)

    Zhao, Yibo; Dang, Haizheng

    2016-01-01

    A two-dimensional axis-symmetric CFD model of a miniature coaxial Stirling-type pulse tube cryocooler with an overall weight of 920 g operating at 128 Hz is established, and systematic simulations of the performance characteristics at different temperatures are conducted. Both thermal equilibrium and non-equilibrium mechanisms for the porous matrix are considered, and the regenerator losses including the gas and solid conduction, the pressure drop and the imperfect interfacial heat transfer are calculated, respectively. The results indicate that the pressure drop loss is dominant during the first 85% and 78% of regenerator length for the thermal equilibrium and non-equilibrium models, respectively, and it decreases monotonously from warm to cold end due to the steadily decreasing Darcy and Forchheimer terms, whereas other entropy generations share similar changing tendencies, going up gradually near the warm end, increasing dramatically from about 60% of length and then decreasing sharply near the cold end. The reasons for these entropy variations are discussed.

  20. Application of longitudinal and transversal bioimpedance measurements in peritoneal dialysis at 50 kHz

    NASA Astrophysics Data System (ADS)

    Nescolarde, L.; Doñate, T.; Casañas, R.; Rosell-Ferrer, J.

    2010-04-01

    More relevant information of the fluid changes in peritoneal dialysis (PD) might be obtained with segmental bioimpedance measurements rather than whole-body measurement, who hidden information of body composition. Whole-body and segmental bioimpedance measurements were obtained using 5 configurations (whole-body or right-side (RS), longitudinal-leg (L-LEG), longitudinal-abdomen (L-AB), transversal-abdomen (T-AB), and transversal-leg (T-LEG)) in 20 patients: 15 males (56.5 ± 9.4 yr, 24.2 ± 4.2 kg/m2) and 5 females (58.4 ± 7.1 yr, 28.2 ± 5.9 kg/m2) in peritoneal dialysis (PD). The aim of this study is to analyze the relationship between whole-body, longitudinal-segmental (L-LEG and L-AB) and transversal-segmental (TAB and TLEG) bioimpedance measurement at 50 kHz, with clinical parameters of cardiovascular risk, dyslipidemia, nutrition and hydration. The Kolmogorov-Smirnov test was used for the normality test of all variables. Longitudinal bioimpedance parameters were normalized by the height of the patients. The Spearman correlation was used to analyze the correlation between bioimpedance and clinical parameters. The statistical significance was considered with P < 0.05. Transversal bioimpedance measurements have higher correlation with clinical parameters than longitudinal measurements.

  1. Task-sensitive reconfiguration of corticocortical 6-20 Hz oscillatory coherence in naturalistic human performance.

    PubMed

    Saarinen, Timo; Jalava, Antti; Kujala, Jan; Stevenson, Claire; Salmelin, Riitta

    2015-07-01

    Electrophysiological oscillatory coherence between brain regions has been proposed to facilitate functional long-range connectivity within neurocognitive networks. This notion is supported by intracortical recordings of coherence in singled-out corticocortical connections in the primate cortex. However, the manner in which this operational principle manifests in the task-sensitive connectivity that supports human naturalistic performance remains undercharacterized. Here, we demonstrate task-sensitive reconfiguration of global patterns of coherent connectivity in association with a set of easier and more demanding naturalistic tasks, ranging from picture comparison to speech comprehension and object manipulation. Based on whole-cortex neuromagnetic recording in healthy behaving individuals, the task-sensitive component of long-range corticocortical coherence was mapped at spectrally narrow-band oscillatory frequencies between 6 and 20 Hz (theta to alpha and low-beta bands). This data-driven cortical mapping unveiled markedly distinct and topologically task-relevant spatiospectral connectivity patterns for the different tasks. The results demonstrate semistable oscillatory states relevant for neurocognitive processing. The present findings decisively link human behavior to corticocortical coherence at oscillatory frequencies that are widely thought to convey long-range, feedback-type neural interaction in cortical functional networks.

  2. Precise measurement of dielectric properties at frequencies from 1 kHz to 100 MHz

    NASA Astrophysics Data System (ADS)

    Kakimoto, Akira; Etoh, Akihiro; Hirano, Kaoru; Nonaka, Satoshi

    1987-02-01

    This paper describes an improved apparatus to measure dielectric constants and dissipation factors using a resonance technique. The measurements can be made rapidly and accurately without appreciable systematic error in the wide frequency range from 1 kHz to 100 MHz. This apparatus uses the half power-gap variation method or the half power-varying gap-immersion method for solid-plate specimens and the solid-plate displacement method for liquid specimens. The electrode system is 30 mm in diameter and has a shield ring to avoid the edge capacitance effect, guards against surface current leakage, and variable air capacitors to set the electrode gap at any arbitrary value. To detect a very small power loss, the resonance voltages in circuits with Q≂100 are stabilized to -86 dB at a constant ambient temperature. We use phase detectors so that the electrode gap and the voltage at resonance can easily be read from the digital panel meter and the digital voltmeter. No corrections are necessary even at a high frequency of 100 MHz. The accuracy of measurements made using the half power-varying gap-immersion method is within 0.2% for the dielectric constant and 3% for the dissipation factor without marked degradation over the entire frequency range.

  3. The impingement of a kHz helium atmospheric pressure plasma jet on a dielectric surface

    NASA Astrophysics Data System (ADS)

    Guaitella, O.; Sobota, A.

    2015-06-01

    A parametric study of the impingement of a helium kHz atmospheric pressure plasma jet on a flat glass surface was performed by means of time-resolved intensified charge-coupled device imaging. The development of the plasma on the target is linked to the plasma evolution in the source and governed by the power supply. The glass surface takes part in the elongation of the plasma jet by the virtue of two mechanisms: the local enhancement of the electric field and the supply of pre-deposited charge. The evidence for the pre-deposited charge is the formation of a sheath on the glass surface, and the faint discharge formed on the glass surface during the negative voltage slope starting at the maximum of the negative current peak. The influence of the gas flow dynamics taking into account various gas flows, incident angles and distances is more important for the behaviour of the discharge on the surface than the voltage amplitude or the geometry of the source. The capacitance of the target strongly modifies the interaction with the plasma jet and increases the deposited surface charge density, featuring a streamer-like propagation mechanism in the case of high electric field enhancement at the surface.

  4. A Stable 200TW / 1Hz Ti:sapphire laser for driving full coherent XFEL

    NASA Astrophysics Data System (ADS)

    Xu, Yi; Lu, Jun; Li, Wenkai; Wu, Fenxiang; Li, Yanyan; Wang, Cheng; Li, Zhaoyang; Lu, Xiaoming; Liu, Yanqi; Leng, Yuxin; Li, Ruxin; Xu, Zhizhan

    2016-05-01

    Basic features of the ultra-short Ti:sapphire laser for driving compact X-ray free electron laser (XFEL) seeded by laser-driven high harmonic generation (HHG) at SIOM (Shanghai, China) is presented. The laser system consists of four-stage Ti:sapphire amplifiers and can produce 8 J energy at 1 Hz repetition rate after the final power amplifier. The best shot-to-shot energy fluctuation is as low as 0.54% in rms value, which is a desirable characteristic for driving stable electron acceleration and HHG seed. After compression, maximal pulse energy of 5.6 J and pulse duration of 27 fs can be obtained, the corresponding pulse peak power is above 200 TW. To achieve full coherent XFEL, the amplified chirped laser beam is split into two beams after the final power amplifier. After compression in two independent compressors, the two laser beams can be used to drive laser wakefield acceleration (LWFA) and HHG respectively. The benefit of such a scheme is to improve the timing jitter and achieve all-optical synchronization between the electron beam and HHG seed in the near future.

  5. Biological studies of swine exposed to 60-Hz electric fields. Volume 2: Behavior. Final report

    SciTech Connect

    Not Available

    1985-12-01

    The behavioral responses in three generations of miniature swine chronically exposed to a 30-kV/m, 60-Hz electric field have been assessed in a series of screening experiments. Tests were conducted on mature swine as well as on very young swine and weanlings and included measures of: (1) preference for exposure to or shielding from the electric field; (2) early neuromuscular development; (3) exploratory behavior; (4) simple learning and memory function; and (5) short-term memory. Repeated evaluations of behavioral parameters show few statistically significant effects. In the parental (F/sub 0/) generation, exposed sows showed a preference to remain out of the field, particularly during the dark period. Adult first-generation (F/sub 1/) sows, however, failed to demonstrate such a preference to stay out of the field. In other behavioral assessments, the singular significant effect in F/sub 1/ swine was the increased number of vocalizations in both male and female swine during the exploratory behavior test. This result, also inconsistent across generations, was not repeated in the second-generation (F/sub 2/) exploratory tests, where exposed female swine made significantly fewer vocalizations than their sham-exposed counterparts. The study provides no other evidence of an overall behavioral effect in swine of prenatal exposure to electric fields. 13 refs., 5 figs., 11 tabs.

  6. Test-Retest Reliability of the 40 Hz EEG Auditory Steady-State Response

    PubMed Central

    McFadden, Kristina L.; Steinmetz, Sarah E.; Carroll, Adam M.; Simon, Steven T.; Wallace, Alissa; Rojas, Donald C.

    2014-01-01

    Auditory evoked steady-state responses are increasingly being used as a marker of brain function and dysfunction in various neuropsychiatric disorders, but research investigating the test-retest reliability of this response is lacking. The purpose of this study was to assess the consistency of the auditory steady-state response (ASSR) across sessions. Furthermore, the current study aimed to investigate how the reliability of the ASSR is impacted by stimulus parameters and analysis method employed. The consistency of this response across two sessions spaced approximately 1 week apart was measured in nineteen healthy adults using electroencephalography (EEG). The ASSR was entrained by both 40 Hz amplitude-modulated white noise and click train stimuli. Correlations between sessions were assessed with two separate analytical techniques: a) channel-level analysis across the whole-head array and b) signal-space projection from auditory dipoles. Overall, the ASSR was significantly correlated between sessions 1 and 2 (p<0.05, multiple comparison corrected), suggesting adequate test-retest reliability of this response. The current study also suggests that measures of inter-trial phase coherence may be more reliable between sessions than measures of evoked power. Results were similar between the two analysis methods, but reliability varied depending on the presented stimulus, with click train stimuli producing more consistent responses than white noise stimuli. PMID:24465679

  7. Experimental investigation of photoresist etching by kHz AC atmospheric pressure plasma jet

    NASA Astrophysics Data System (ADS)

    Wang, Lijun; Zheng, Yashuang; Wu, Chen; Jia, Shenli

    2016-11-01

    In this study, the mechanism of the photoresist (PR) etching by means of a kHz AC atmospheric pressure plasma jet (APPJ) is investigated. The scanning electron (SEM) and the polarizing microscope are used to perform the surface analysis, and the mechanical profilometry is applied to diagnose the etch rate. The results show that granulated structure with numerous microparticles appears at the substrate surface after APPJ treatment, and the etch rate in the etch center is the fastest and gradually slows down to the edge of etch region. In addition, the pin-ring electrode APPJ has the highest etch rate at but easy to damage the Si wafer, the double-ring APPJ is the most stable but requires long time to achieve the ideal etch result, and the etch rate and the etch result of the multi-electrode APPJ fall in between. Ar APPJ had much higher PR etch rate and more irregular etch trace than He APPJ. It is speculated that Ar APPJ is more energetic and effective in transferring reactive species to the PR surface. It is also observed that the effective etch area initially increases and then decreases as plasma jet outlet to the PR surface distance increases.

  8. Nonhuman primates will not respond to turn off strong 60 Hz electric fields

    SciTech Connect

    Rogers, W.R.; Orr, J.L.; Smith, H.D.

    1995-12-31

    Using a set of six baboons (Papio cynocephalus), the authors conducted a series of seven experiments designed to evaluate the potentially aversive character of a 60 Hz electric field (EF). Initially, the subjects were trained, using food rewards as the reinforcer, to respond only when a cue light was illuminated. Next, an EF was presented along with the cue light; responses produced delivery of a food pellet and turned off both the cue light and the EF. Then, stimulus and reward conditions were varied. The authors determined that (1) presence of a strong EF does not affect operant responding for food rewards, (2) subjects will not respond at normal rates when the only reinforcer is termination of a strong EF, (3) presence of a strong EF can serve as a discriminative stimulus, (4) presence of a strong EF does not affect extinction of an appetite-motivated task, and (5) presentation of an EF can become a secondary reinforcer. The pattern of results was consistent across all experiments, suggesting that an EF of as much as 65 kV/m is not aversive to nonhuman primates. Separately, the authors demonstrated that the average EF detection threshold for baboons is 12 kV/m. Thus, EF exposure at intensities well above the detection threshold and at species-scaled EF strengths greater than those found environmentally does not appear to be aversive.

  9. Molecular Spectroscopy in Hollow-Core Photonic Crystal Fiber at the 10 kHz Level

    NASA Astrophysics Data System (ADS)

    Wang, Chenchen; Knabe, Kevin; Wu, Shun; Lim, Jinkang; Tillman, Karl; Washburn, Brian; Corwin, Kristan; Wheeler, Natalie; Couny, Francois; Benabid, Fetah

    2010-03-01

    High-accuracy spectroscopy in hollow-core photonic crystal fiber (HC-PCF) is desirable for many applications, including frequency references and trace gas analysis. We demonstrate the narrowest sub-Doppler linewidths attained in HC-PCF using large-core kagome structured fiber. Such fibers can yield highly accurate frequency measurements that are about two orders of magnitude higher than previously reported. A fiber laser is locked to the ^12C2H2 ν1+ν3 P(13) transition inside kagome fiber, and compared with two optical frequency combs referenced to a GPS-disciplined Rb oscillator. The absolute frequency of the measured line center agrees with those measured in power build-up cavities to within 9.3 kHz (1 σ error). Approaches to further narrow the linewidths and improve systematic errors are investigated. The present system thus combines accuracy approaching that of power build-up cavities with the potential to be compact, robust, and integrated into an all-fiber system for a portable near-infrared frequency reference. Supported by AFOSR FA9950-05-1-0304 and NSF ECS-0449295.

  10. Correlations between X-ray Spectra and kHz QPOS in Sco X-1

    NASA Astrophysics Data System (ADS)

    Bradshaw, Charles F.; Titarchuk, Lev; Kuznetsov, Sergey

    2008-05-01

    Recent analysis of the RXTE X-ray spectra of Sco X-1 discovered that Sco X-1 can be adequately modeled by a simple two-component model of Compton up-scattering with a soft photon electron temperature of about 0.4 keV, plus an Iron K-line. The results show a strong correlation between spectral power law index and kHz QPOs. Sco X-1 is the prototypical Z-source low-mass X-ray binary (LMXB) system radiating near the Eddington limit. This radiation produces a high radiation pressure in its Compton cloud. We infer that the radiation pressure produces a geometrical configuration of the cloud that is quasi-spherical. We conclude that the high Thomson optical depth of the Compton cloud, in the range of 5-6 from the best-fit model parameters, is consistent with the neutron star's surface being obscured by material, which would likely suppress a spin frequency of Sco X-1 due to photon scattering off cloud electrons. We also demonstrate the evolution of its power spectrum when Sco X-1 transitions from the horizontal branch to the normal branch.

  11. What the [bleep]? Enhanced absolute pitch memory for a 1000Hz sine tone.

    PubMed

    Van Hedger, Stephen C; Heald, Shannon L M; Nusbaum, Howard C

    2016-09-01

    Many individuals are able to perceive when the tuning of familiar stimuli, such as popular music recordings, has been altered. This suggests a kind of ubiquitous pitch memory, though it is unclear how this ability differs across individuals with and without absolute pitch (AP) and whether it plays any role in AP. In the present study, we take advantage of a salient single frequency - the 1000Hz sine tone used to censor taboo words in broadcast media - to assess the nature of this kind of pitch memory across individuals with and without AP. We show that non-AP participants are accurate at selecting the correct version of the censor tone among incorrect versions shifted by either one or two semitones, though their accuracy was still below that of an AP population (Experiment 1). This suggests a benefit for AP listeners that could be due to the use of explicit note categories or greater amounts of musical training. However, AP possessors still outperformed all non-AP participants when incorrect versions of the censor tone were shifted within a note category, even when controlling for musical experience (Experiment 2). Experiment 3 demonstrated that AP listeners did not appear to possess a category label for the censor tone that could have helped them differentiate the censor tones used in Experiment 2. Overall, these results suggest that AP possessors may have better pitch memory, even when divorced from pitch labeling (note categories). As such, these results have implications for how AP may develop and be maintained. PMID:27289485

  12. Behavioral responses of California sea lions to mid-frequency (3250-3450 Hz) sonar signals.

    PubMed

    Houser, Dorian S; Martin, Stephen W; Finneran, James J

    2013-12-01

    Military sonar has the potential to negatively impact marine mammals. To investigate factors affecting behavioral disruption in California sea lions (Zalophus californianus), fifteen sea lions participated in a controlled exposure study using a simulated tactical sonar signal (1 s duration, 3250-3450 Hz) as a stimulus. Subjects were placed into groups of three and each group received a stimulus exposure of 125, 140, 155, 170, or 185 dB re: 1 μPa (rms). Each subject was trained to swim across an enclosure, touch a paddle, and return to the start location. Sound exposures occurred at the mid-point of the enclosure. Control and exposure sessions were run consecutively and each consisted of ten, 30-s trials. The occurrence and severity of behavioral responses were used to create acoustic dose-response and dose-severity functions. Age of the subject significantly affected the dose-response relationship, but not the dose-severity relationship. Repetitive exposures did not affect the dose-response relationship.

  13. Effects of 76 Hz electromagnetic fields on forest ecosystems in northern Michigan: Tree growth

    NASA Astrophysics Data System (ADS)

    Reed, David D.; Jones, Elizabeth A.; Mroz, Glenn D.; Liechty, Hal O.; Cattelino, Peter J.; Jürgensen, Martin F.

    1993-12-01

    Since 1984, the possible effects of extremely low-frequency electromagnetic (EM) fields generated by a 76 Hz communication antenna on the growth and productivity of four deciduous and one coniferous species have been studied in the Upper Peninsula of Michigan. Results from two research sites are discussed here: one site near an antenna element and a control site located 50 km from the communication system. Growth models for individual tree diameters were developed for northern red oak ( Quercus rubra), paper birch ( Betula papyrifera), aspen ( Populus tremuloides with a few individuals of P. grandidentata), and red maple ( Acer rubrum). A growth model for individual tree height was developed for young red pine ( Pinus resinosa). Average differences between the observed and predicted growth were calculated for each growing season and then compared between the study sites and across the study periods to evaluate changes in growth patterns which could be attributed to EM field effects. For aspen and red maple, the results showed a stimulation of diameter growth at magnetic flux density levels of 1 to 7 milliGauss; height growth of red pine was increased at about the same exposure levels. There are no clear indications of an EM field effect on total annual diameter growth for either of the other two species.

  14. Femtosecond Coherent Anti-Stokes Raman Scattering Gas Phase Thermometry at 5 kHz

    NASA Astrophysics Data System (ADS)

    Fineman, Claresta; Lucht, Robert

    2014-05-01

    Understanding the thermal instabilities occurring in turbulent combustion, such as in modern gas turbine combustors, is critical for more reliable and fuel-efficient operation. Non-intrusive laser based spectroscopy methods have been documented as the techniques of choice for turbulent combustion diagnostics. Specifically, femtosecond coherent anti-Stokes Raman scattering (fs-CARS) thermometry has been established for temporal resolution of turbulent fluctuations in flame structure and provides accurate measurements across a wide range of temperatures. Experiments performed to date include 5 kHz pure vibrational N2 chirped probe-pulse fs-CARS thermometry on non-premixed hydrogen jet diffusion flames, methane jet diffusion flames, and the DLR gas turbine model combustor (GTMC). The fs-CARS signal generation process requires precise spatial and temporal overlap of tightly focused pulsed laser beams of less than 100 fs pulse duration. Here, signal loss due to beam steering, pressure fluctuations, or shear layer density gradients can become a problem. The effect of such interferences has been investigated using high velocity flow of compressed nitrogen gas from a converging-diverging nozzle. Resulting changes in fs-CARS spectra have been studied. Funding for this work was provided by the U.S. Department of Energy, Division of Chemical Sciences, Geosciences and Biosciences.

  15. Disinfection of wastewater using a 20-kHz ultrasound unit.

    PubMed

    Madge, Bethany A; Jensen, James N

    2002-01-01

    The present study explored the application of a 20-kHz ultrasound unit for the disinfection of domestic wastewater. Experiments were conducted in batch with an ultrasound probe. The disinfection efficiency of fecal coliform increased with ultrasound power input from 0.003 log kill/min at 70 W/L to 1.8 log kill/min at 1250 W/L. Disinfection data are well-described by the Chick-Watson disinfection model (coefficient of dilution, n = 2.0) using ultrasound power in place of chemical concentration. Water quality did not affect disinfection efficiency significantly. Temperature increases experienced with ultrasonic treatment were significant. Attempts to control the temperature resulted in a marked decrease in disinfection efficiency. Experiments devised to quantify the role of thermal mechanisms revealed that of the total kill produced by ultrasound approximately 52% was attributed to heat, 36% to mechanical stresses associated with ultrasonically induced cavitation, and 12% to uncharacterized synergistic effects. Successful scale-up was demonstrated using a 9.3-L pilot-scale ultrasound unit, operated under flow-through conditions.

  16. Acoustic effects of the ATOC signal (75 Hz, 195 dB) on dolphins and whales.

    PubMed

    Au, W W; Nachtigall, P E; Pawloski, J L

    1997-05-01

    The Acoustic Thermometry of Ocean Climate (ATOC) program of Scripps Institution of Oceanography and the Applied Physics Laboratory, University of Washington, will broadcast a low-frequency 75-Hz phase modulated acoustic signal over ocean basins in order to study ocean temperatures on a global scale and examine the effects of global warming. One of the major concerns is the possible effect of the ATOC signal on marine life, especially on dolphins and whales. In order to address this issue, the hearing sensitivity of a false killer whale (Pseudorca crassidens) and a Risso's dolphin (Grampus griseus) to the ATOC sound was measured behaviorally. A staircase procedure with the signal levels being changed in 1-dB steps was used to measure the animals' threshold to the actual ATOC coded signal. The results indicate that small odontocetes such as the Pseudorca and Grampus swimming directly above the ATOC source will not hear the signal unless they dive to a depth of approximately 400 m. A sound propagation analysis suggests that the sound-pressure level at ranges greater than 0.5 km will be less than 130 dB for depths down to about 500 m. Several species of baleen whales produce sounds much greater than 170-180 dB. With the ATOC source on the axis of the deep sound channel (greater than 800 m), the ATOC signal will probably have minimal physical and physiological effects on cetaceans.

  17. Slope Instability on the French Guiana Transform Margin from Swath-Bathymetry and 3.5 kHz Echograms

    NASA Astrophysics Data System (ADS)

    Gaullier, Virginie; Loncke, Lies; Droz, Laurence; Basile, Christophe; Maillard, Agnès.; Patriat, Martin; Roest, Walter R.; Loubrieu, Benoît.

    2010-05-01

    sedimentary structures are observed on the Demerara Abyssal Plain: small meandering channels of the Amazon Fan at its eastern edge and sediment waves at its western edge, along the foot of Demerara continental slope. Another remarkable characteristic of the study area is the abundance of circular and elongated bathymetric depressions corresponding to pockmarks, on the margin and in the abyssal plain. Fluid escape features are also documented on 3.5 kHz echograms. Our dataset does not allow any speculation concerning the origin of the fluids, but good candidates could be the Black Shales or Cretaceous organic-rich layers on the Demerara Plateau, as suggested by Erbacher et al. (2004). In any case, these fluid escape structures seem to be closely related with slope instabilities, either along bounding faults acting as drains, or by surficial dewatering of debris flows. Whether the deformation observed at the surface is the imprint of ancient events or active features is still unclear. Given the freshness of deformations and the abundance of pockmarks, we believe that the seaward creeping processes experienced by the whole Demerara plateau are active today. Future work will be dedicated to a better understanding of the relations between structural inheritance (i.e. transform context), slope instability and fluid escape.

  18. Improved Mitochondrial and Methylglyoxal-Related Metabolisms Support Hyperproliferation Induced by 50 Hz Magnetic Field in Neuroblastoma Cells.

    PubMed

    Falone, Stefano; Santini, Silvano; di Loreto, Silvia; Cordone, Valeria; Grannonico, Marta; Cesare, Patrizia; Cacchio, Marisa; Amicarelli, Fernanda

    2016-09-01

    Extremely low frequency magnetic fields (ELF-MF) are common environmental agents that are suspected to promote later stages of tumorigenesis, especially in brain-derived malignancies. Even though ELF magnetic fields have been previously linked to increased proliferation in neuroblastoma cells, no previous work has studied whether ELF-MF exposure may change key biomolecular features, such as anti-glycative defence and energy re-programming, both of which are currently considered as crucial factors involved in the phenotype and progression of many malignancies. Our study investigated whether the hyperproliferation that is induced in SH-SY5Y human neuroblastoma cells by a 50 Hz, 1 mT ELF magnetic field is supported by an improved defense towards methylglyoxal (MG), which is an endogenous cancer-static and glycating α-oxoaldehyde, and by rewiring of energy metabolism. Our findings show that not only the ELF magnetic field interfered with the biology of neuron-derived malignant cells, by de-differentiating further the cellular phenotype and by increasing the proliferative activity, but also triggered cytoprotective mechanisms through the enhancement of the defense against MG, along with a more efficient management of metabolic energy, presumably to support the rapid cell outgrowth. Intriguingly, we also revealed that the MF-induced bioeffects took place after an initial imbalance of the cellular homeostasis, which most likely created a transient unstable milieu. The biochemical pathways and molecular targets revealed in this research could be exploited for future approaches aimed at limiting or suppressing the deleterious effects of ELF magnetic fields. J. Cell. Physiol. 231: 2014-2025, 2016. © 2016 Wiley Periodicals, Inc. PMID:26757151

  19. Statistical analysis of Stromboli VLP tremor in the band [0.1-0.5] Hz: some consequences for vibrating structures

    NASA Astrophysics Data System (ADS)

    de Lauro, E.; de Martino, S.; Falanga, M.; Palo, M.

    2006-08-01

    We analyze time series of Strombolian volcanic tremor, focusing our attention on the frequency band [0.1-0.5] Hz (very long period (VLP) tremor). Although this frequency band is largely affected by noise, we evidence two significant components by using Independent Component Analysis with the frequencies, respectively, of ~0.2 and ~0.4 Hz. We show that these components display wavefield features similar to those of the high frequency Strombolian signals (>0.5 Hz). In fact, they are radially polarised and located within the crater area. This characterization is lost when an enhancement of energy appears. In this case, the presence of microseismic noise becomes relevant. Investigating the entire large data set available, we determine how microseismic noise influences the signals. We ascribe the microseismic noise source to Scirocco wind. Moreover, our analysis allows one to evidence that the Strombolian conduit vibrates like the asymmetric cavity associated with musical instruments generating self-sustained tones.

  20. A recirculating delayed self-heterodyne method using a Mach-Zehnder modulator for kHz-linewidth measurement

    NASA Astrophysics Data System (ADS)

    Deng, Shuo; Li, Min; Gao, Hongyun; Dai, Yawen

    2016-09-01

    A laser linewidth measurement method which uses a Mach-Zehnder electro-optic modulator (MZM) is proposed in a loss-compensated recirculating delayed self-heterodyne interferometer (LC-RDSHI). Compared with the traditional acousto-optic modulator (AOM), the electro-optic modulator has the merits of broader bandwidth, lower insertion loss, higher extinction ratio and thus, a wider application. A theoretical analysis shows that the power spectrum curve of the novel measurement system is a Lorentzian line, which fits well with experiment. The linewidth is measured to be 137 ± 7 kHz at a frequency shift of 4 GHz. Measurement of a distributed feedback Bragg (DFB) laser has manifested that the linewidth broadens from 98.5 kHz to 137.4 kHz as the operating temperature changes by 16 °C. This work will allow investigation of narrow linewidth semiconductor and fiber laser stability.