Science.gov

Sample records for 4-8 hz alpha

  1. Mechanism and kinetics of carbide dissolution in near alpha Ti-5.6Al-4.8Sn-2Zr-1Mo-0.35Si-0.7Nd titanium alloy

    SciTech Connect

    Zhang, S.Z.; Li, M.M.; Yang, R.

    2011-12-15

    The present work evaluates the influence of bulk carbon content and aging temperature on the stability of carbide in near alpha Ti-5.6Al-4.8Sn-2Zr-1Mo-0.35Si-0.7Nd titanium alloy. The carbide particles were formed during heat treatment in the {beta} phase field and preserved by water quenching. Subsequent aging treatments at 750-850 Degree-Sign C caused partial dissolution of these precipitates, as a result of the peritectoid reaction between the {beta} phase and carbide. The models based on interface reaction controlled dissolution, via uniform atomic detachment, dislocation mechanism or vacancy flow, yielded experimental predictions comparable to the observed dissolution kinetics. Furnace cooling after heat treatment in the {beta} phase field dissolved carbide particles completely, and the microstructure changed from acicular-like or block {alpha} to equiaxed {alpha} with increase of carbon content. - Highlights: Black-Right-Pointing-Pointer Carbide dissolution occurs at precipitate/matrix interfaces, forming {beta}-depleted zone. Black-Right-Pointing-Pointer Peritectoid reaction is responsible for drastic reduction of carbide volume fraction. Black-Right-Pointing-Pointer Slower dissolution rate is accounted by dislocation, vacancy flow, and curvature. Black-Right-Pointing-Pointer Lamellar changed to equiaxed {alpha} with increasing carbon from {beta} furnace cooling.

  2. Umbra Ver. 4.8

    SciTech Connect

    Oppel, III, Fred; Hart, Brian; Hart, Derek; Linebarger, John; Rigdon, J. Brian; Wolfenbarger, Paul; Xavier, Patrick; & Gottlieb, Eric

    2010-02-24

    Umbra is a software package that has been in development at Sandia National Laboratories since 1995, under the name Umbra since 1997. Umbra is a software framework written in C++ and Tcl/Tk that has been applied to many operations, primarily dealing with robotics and simulation. Umbra executables are C++ libraries orchestrated with Tcl/Tk scripts. Two major feature upgrades occurred from 4.7 to 4.8 1. System Umbra Module with its own Update Graph within the C++ framework. 2. New terrain graph for fast line-of-sight calculations All else were minor updates such as later versions of Visual Studio, OpenSceneGraph and Boost.

  3. Umbra Ver. 4.8

    2010-02-24

    Umbra is a software package that has been in development at Sandia National Laboratories since 1995, under the name Umbra since 1997. Umbra is a software framework written in C++ and Tcl/Tk that has been applied to many operations, primarily dealing with robotics and simulation. Umbra executables are C++ libraries orchestrated with Tcl/Tk scripts. Two major feature upgrades occurred from 4.7 to 4.8 1. System Umbra Module with its own Update Graph within the C++more » framework. 2. New terrain graph for fast line-of-sight calculations All else were minor updates such as later versions of Visual Studio, OpenSceneGraph and Boost.« less

  4. 28 CFR 4.8 - Hearing.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 1 2011-07-01 2011-07-01 false Hearing. 4.8 Section 4.8 Judicial... OF 1974 § 4.8 Hearing. The hearing on the application shall be held at the offices of the Commision in Washington, DC, or elsewhere as the Commission may direct. The hearing shall be held before...

  5. 28 CFR 4.8 - Hearing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Hearing. 4.8 Section 4.8 Judicial... OF 1974 § 4.8 Hearing. The hearing on the application shall be held at the offices of the Commision in Washington, DC, or elsewhere as the Commission may direct. The hearing shall be held before...

  6. 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

  7. 15 CFR 4.8 - Classified Information.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 1 2012-01-01 2012-01-01 false Classified Information. 4.8 Section 4... INFORMATION Freedom of Information Act § 4.8 Classified Information. In processing a request for information classified under Executive Order 12958 or any other executive order concerning the classification of...

  8. 15 CFR 4.8 - Classified Information.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 1 2013-01-01 2013-01-01 false Classified Information. 4.8 Section 4... INFORMATION Freedom of Information Act § 4.8 Classified Information. In processing a request for information classified under Executive Order 12958 or any other executive order concerning the classification of...

  9. 15 CFR 4.8 - Classified Information.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 1 2014-01-01 2014-01-01 false Classified Information. 4.8 Section 4... INFORMATION Freedom of Information Act § 4.8 Classified Information. In processing a request for information classified under Executive Order 12958 or any other executive order concerning the classification of...

  10. 15 CFR 4.8 - Classified Information.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 1 2011-01-01 2011-01-01 false Classified Information. 4.8 Section 4... INFORMATION Freedom of Information Act § 4.8 Classified Information. In processing a request for information classified under Executive Order 12958 or any other executive order concerning the classification of...

  11. 15 CFR 4.8 - Classified Information.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Classified Information. 4.8 Section 4... INFORMATION Freedom of Information Act § 4.8 Classified Information. In processing a request for information..., the information shall be reviewed to determine whether it should remain classified. Ordinarily...

  12. Measurement of the 4. 8-MeV /sup 9/B state width by the reaction /sup 10/B(/sup 3/He,. cap alpha. )/sup 9/B(. cap alpha. ) /sup 5/Li at E( /sup 3/He) = 2. 3 and 5. 0 MeV

    SciTech Connect

    Arena, N.; Cavallaro, S.; Fazio, G.; Giardina, G.; Italiano, A.; Mezzanares, F.

    1986-10-13

    The analog of the 4.7-MeV state of the /sup 9/Be nucleus has been observed in its mirror /sup 9/B by the reaction /sup 10/B(/sup 3/He, ..cap alpha..)/sup 9/B(..cap alpha..) /sup 5/Li (g.s.) at E( /sup 3/He) = 2.3 and 5.0 MeV. The excitation energy and width of the state have been deduced. The value of 1.5 +- 0.3 MeV found for the width is in line with the value deduced by the reaction /sup 7/Li(/sup 3/He,n) /sup 9/B, but it is larger by a factor of about 4 than the one measured by the proton following the ..beta../sup +/ decay of the /sup 9/C nucleus.

  13. Adaptive 4-8 Texture Hierarchies

    SciTech Connect

    Hwa, L M; Duchaineau, M A; Joy, K I

    2004-08-02

    We address the texture level-of-detail problem for extremely large surfaces such as terrain during real-time, view-dependent rendering. A novel texture hierarchy is introduced based on 4-8 refinement of raster tiles, in which the texture grids in effect rotate 45 degrees for each level of refinement. This hierarchy provides twice as many levels of detail as conventional quad-tree-style refinement schemes such as mipmaps, and thus provides per-pixel view-dependent filtering that is twice as close to the ideal cutoff frequency for an average pixel. Because of this more gradual change in low-pass filtering, and due to the more precise emulation of the ideal cutoff frequency, we find in practice that the transitions between texture levels of detail are not perceptible. This allows rendering systems to avoid the complexity and performance costs of per-pixel blending between texture levels of detail. The 4-8 texturing scheme is integrated into a variant of the Real-time Optimally Adapting Meshes (ROAM) algorithm for view-dependent multiresolution mesh generation. Improvements to ROAM included here are: the diamond data structure as a streamlined replacement for the triangle bintree elements, the use of low-pass-filtered geometry patches in place of individual triangles, integration of 4-8 textures, and a simple out-of-core data access mechanism for texture and geometry tiles.

  14. 16 CFR 4.8 - Costs for obtaining Commission records.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Costs for obtaining Commission records. 4.8 Section 4.8 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE MISCELLANEOUS RULES § 4.8 Costs for obtaining Commission records. (a) Definitions. For the purpose of...

  15. Elementary Acid Rain Kit, Interdisciplinary, Grades 4-8.

    ERIC Educational Resources Information Center

    Stubbs, Harriett S.; And Others

    An interdisciplinary approach for teaching about acid rain is offered in this curriculum guide for teachers of grades 4-8. Skill and concept areas of science, math, social studies, art, and the language arts are developed in 12 activities which focus on the acid rain problems. A matrix of the activities and subject areas indicates the coverage…

  16. Portraits of Outstanding Explorers. Grades 4-8+.

    ERIC Educational Resources Information Center

    Metcalf, Doris Hunter

    This resource book provides information and activity sheets on explorers of North America. The five sections of the book trace the explorers' contributions both geographically and chronologically. Each section includes thought questions, biographical portraits and skill activities for grades 4-8. Section 1, "They Opened the Door," profiles Leif…

  17. Let's Celebrate Autumn: Activities for Grades 4-8.

    ERIC Educational Resources Information Center

    Kern County Superintendent of Schools, Bakersfield, Ca. Div. of Instructional Services.

    One of a series of activity guides, this publication offers a variety of learning activities and resource materials to help teachers and students celebrate special days and events in autumn. The activities and resources are especially designed to develop communications skills of students in grades 4-8; however, they are easily transferable to…

  18. 16 CFR 4.8 - Costs for obtaining Commission records.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... specific services are set forth in § 4.8(b)(6). (b) Fees. User fees pursuant to 31 U.S.C. 483(a) and 5 U.S...) Educational requesters, non-commercial scientific institution requesters, and representative of the news media... to promote any particular product or industry. A representative of the news media is any...

  19. 17 CFR 275.206(4)-8 - Pooled investment vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 17 Commodity and Securities Exchanges 3 2012-04-01 2012-04-01 false Pooled investment vehicles... COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT ADVISERS ACT OF 1940 § 275.206(4)-8 Pooled investment vehicles. (a) Prohibition. It shall constitute a fraudulent, deceptive, or manipulative...

  20. 17 CFR 275.206(4)-8 - Pooled investment vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Pooled investment vehicles... COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT ADVISERS ACT OF 1940 § 275.206(4)-8 Pooled investment vehicles. (a) Prohibition. It shall constitute a fraudulent, deceptive, or manipulative...

  1. 17 CFR 275.206(4)-8 - Pooled investment vehicles.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Pooled investment vehicles... COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT ADVISERS ACT OF 1940 § 275.206(4)-8 Pooled investment vehicles. (a) Prohibition. It shall constitute a fraudulent, deceptive, or manipulative...

  2. 42 CFR 4.8 - Publication of the Library and information about the Library.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Publication of the Library and information about the Library. 4.8 Section 4.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS NATIONAL LIBRARY OF MEDICINE § 4.8 Publication of the Library and...

  3. 42 CFR 4.8 - Publication of the Library and information about the Library.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Publication of the Library and information about the Library. 4.8 Section 4.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS NATIONAL LIBRARY OF MEDICINE § 4.8 Publication of the Library and...

  4. 42 CFR 4.8 - Publication of the Library and information about the Library.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Publication of the Library and information about the Library. 4.8 Section 4.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS NATIONAL LIBRARY OF MEDICINE § 4.8 Publication of the Library and...

  5. 42 CFR 4.8 - Publication of the Library and information about the Library.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Publication of the Library and information about the Library. 4.8 Section 4.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS NATIONAL LIBRARY OF MEDICINE § 4.8 Publication of the Library and...

  6. 42 CFR 4.8 - Publication of the Library and information about the Library.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Publication of the Library and information about the Library. 4.8 Section 4.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS NATIONAL LIBRARY OF MEDICINE § 4.8 Publication of the Library and...

  7. Resting-State Alpha in Autism Spectrum Disorder and Alpha Associations with Thalamic Volume

    ERIC Educational Resources Information Center

    Edgar, J. Christopher; Heiken, Kory; Chen, Yu-Han; Herrington, John D.; Chow, Vivian; Liu, Song; Bloy, Luke; Huang, Mingxiong; Pandey, Juhi; Cannon, Katelyn M.; Qasmieh, Saba; Levy, Susan E.; Schultz, Robert T.; Roberts, Timothy P. L.

    2015-01-01

    Alpha circuits (8-12 Hz), necessary for basic and complex brain processes, are abnormal in autism spectrum disorder (ASD). The present study obtained estimates of resting-state (RS) alpha activity in children with ASD and examined associations between alpha activity, age, and clinical symptoms. Given that the thalamus modulates cortical RS alpha…

  8. 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

  9. 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.

  10. Nonperiodic optical flickering in HZ Herculis

    NASA Technical Reports Server (NTRS)

    Moffett, T. J.; Nather, R. E.; Vanden Bout, P. A.

    1974-01-01

    High-speed simultaneous dual-channel photometry of HZ Her and a nearby comparison star reveal nonperiodic optical flickering in the HZ Her system on a time scale of 15 to 300 sec. The amplitude of the flickering appears to be correlated with orbital phase. Optical emission from a hot spot in a disk of material around the X-ray source cannot account for the flickering.

  11. 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

  12. Acetylcholine modulates human working memory and subsequent familiarity based recognition via alpha oscillations.

    PubMed

    Eckart, Cindy; Woźniak-Kwaśniewska, Agata; Herweg, Nora A; Fuentemilla, Lluis; Bunzeck, Nico

    2016-08-15

    Working memory (WM) can be defined as the ability to maintain and process physically absent information for a short period of time. This vital cognitive function has been related to cholinergic neuromodulation and, in independent work, to theta (4-8Hz) and alpha (9-14Hz) band oscillations. However, the relationship between both aspects remains unclear. To fill this apparent gap, we used electroencephalography (EEG) and a within-subject design in healthy humans who either received the acetylcholinesterase inhibitor galantamine (8mg) or a placebo before they performed a Sternberg WM paradigm. Here, sequences of sample images were memorized for a delay of 5s in three different load conditions (two, four or six items). On the next day, long-term memory (LTM) for the images was tested according to a remember/know paradigm. As a main finding, we can show that both theta and alpha oscillations scale during WM maintenance as a function of WM load; this resembles the typical performance decrease. Importantly, cholinergic stimulation via galantamine administration slowed down retrieval speed during WM and reduced associated alpha but not theta power, suggesting a functional relationship between alpha oscillations and WM performance. At LTM, this pattern was accompanied by impaired familiarity based recognition. These findings show that stimulating the healthy cholinergic system impairs WM and subsequent recognition, which is in line with the notion of a quadratic relationship between acetylcholine levels and cognitive functions. Moreover, our data provide empirical evidence for a specific role of alpha oscillations in acetylcholine dependent WM and associated LTM formation. PMID:27222217

  13. Atypical Alpha Asymmetry in Adults with ADHD

    ERIC Educational Resources Information Center

    Hale, T. Sigi; Smalley, Susan L.; Hanada, Grant; Macion, James; McCracken, James T.; McGough, James J.; Loo, Sandra K.

    2009-01-01

    Introduction: A growing body of literature suggests atypical cerebral asymmetry and interhemispheric interaction in ADHD. A common means of assessing lateralized brain function in clinical populations has been to examine the relative proportion of EEG alpha activity (8-12 Hz) in each hemisphere (i.e., alpha asymmetry). Increased rightward alpha…

  14. Investigations Into Accumulator 4-8 GHz Pickup Loop / Combiner Board Performance

    SciTech Connect

    Vander Meuler, D.; /Fermilab

    2000-04-17

    A set of pickup measurements performed in August of 1999 (see Pbar note 618) indicated problems with the pickup sensitivity for frequencies above {approx}4.8 GHz. This note describes the effort made to determine if the problems with system performance were due to the design of the 4-8 GHz circuit board.

  15. Efficient Synthesis of 4,8-Ditoluoyl-1,5-Dihydroxynaphthalene

    NASA Technical Reports Server (NTRS)

    Tyson, Daniel S.; Meador, Michael A.

    2003-01-01

    4,8-Ditoluoyl-1,5-dihydroxynaphthalene was synthesized in quantitative yield from the corresponding methylenequinone via base-catalyzed hydration. Alkaline treatment gives the title compound in one step with a 99% yield, an improvement of 80% compared to the acidic, two step literature method for preparing 4,8-dibenzoyl-1,5-dihydroxynaphthalene.

  16. Enantioselective Separation of 4,8-DHT and Phytotoxicity of the Enantiomers on Various Plant Species.

    PubMed

    Yang, Li; Ma, Xiao-Yan; Ruan, Xiao; Jiang, De-An; Pan, Cun-De; Wang, Qiang

    2016-01-01

    As a candidate for bioherbicide, 4,8-dihydroxy-1-tetralone (4,8-DHT) was isolated from Caryospora callicarpa epicarp and its two enantiomers, S-(+)-isosclerone and R-(-)-regiolone, were separated by chiral high-performance liquid chromatography (HPLC) on a Chiralcel OD column with chiral stationary phase (CSP)-coated cellulose-tris(3,5-dimethylphenylcarbamate). Then, the phytotoxicity of 4,8-DHT and its enantiomers toward the seeds germination and seedling growth of the five tested plant species, including lettuce (Latuca sativa), radish (Raphanus sativus), cucumber (Cucumis sativus), onion (Allium cepa), and wheat (Triticum aestivum), were investigated and the results indicated a hormesis at low concentration of 4,8-DHT and its enantiomers, but a retardant effect at high concentration. Between the two enantiomers of 4,8-DHT, the S-(+)-isosclerone was more toxic to seeds germination and seedling growth of the five tested plant species than the R-(-)-regiolone, and also the phytotoxicity of S-(+)-isosclerone varied with different plants. For example, S-(+)-isosclerone was the most active to seedling growth of lettuce, indicating that S-(+)-isosclerone had specific effects on different organisms. Thus, all of the chirality and concentration of 4,8-DHT, as well as the affected plant species, need to be taken into consideration in the development and utilization of 4,8-DHT. PMID:27110760

  17. Miniature pulse tube cooler at 100HZ

    NASA Astrophysics Data System (ADS)

    Chen, Houlei; Xu, Nana; Yin, Chuanlin; Cai, Jinghui; Liang, Jingtao

    2012-06-01

    Miniature pulse tube coolers operating at 100Hz have been designed and manufactured. The regenerator is designed by REGEN 3.2, and the inertance tube is simulated by DeltaE. An in-line prototype is manufactured according to the theoretical design parameters initially. On that basis, a coaxial cooler is developed and with double inlet it gains higher cooling performance.

  18. 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.

  19. Alpha Particle

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Term that is sometimes used to describe a helium nucleus, a positively charged particle that consists of two protons and two neutrons, bound together. Alpha particles, which were discovered by Ernest Rutherford (1871-1937) in 1898, are emitted by atomic nuclei that are undergoing alpha radioactivity. During this process, an unstable heavy nucleus spontaneously emits an alpha particle and transmut...

  20. A low-noise 4.8 GHz amplifier for the Russian Radioastron VLBI satellite

    NASA Astrophysics Data System (ADS)

    Schmidt, A.; Wongsowijoto, Sam

    A low-noise 4.8 GHz amplifier has been designed for the Russian Radioastron satellite. The design, realization, and spaceflight testing of the amplifier are briefly described. The most important parameters of the prototype are given.

  1. 100-Hz Electroacupuncture but not 2-Hz Electroacupuncture is Preemptive Against Postincision Pain in Rats.

    PubMed

    Silva, Marcelo Lourenço; Silva, Josie Resende Torres; Prado, Wiliam Alves

    2016-08-01

    Preemptive analgesia involves introducing an analgesic before noxious stimulation. Electroacupuncture (EA) activates descending mechanisms that modulate nociceptive inputs into the spinal dorsal horn. This study evaluated whether preoperative EA is more effective than postoperative EA in reducing incision pain in rats. The nociceptive threshold to mechanical stimulation was utilized to examine the effects of an intraperitoneal injection of saline (0.1 mL/kg) or naloxone (1 mg/kg) on antinociception induced by a 20-minute period of 2-Hz or 100-Hz EA applied to the Zusanli (ST36) and Sanyinjiao (SP6) acupoints before surgical incision, or 10 minutes after or 100 minutes after surgical incision of the hind paw. The extent of mechanical hyperalgesia after the incision was significantly attenuated by the application of 100-Hz EA preoperatively, but not by its application at 10 minutes or 100 minutes postoperatively. By contrast, 2-Hz EA was effective against postoperative hyperalgesia when applied 10 minutes or 100 minutes after surgery but not when it was applied preoperatively. Only the effect of 2-Hz EA applied 10 minutes after surgery was sensitive to naloxone. The present study showed for the first time that 100-Hz EA, but not 2-Hz EA, exerts a nonopioidergic preemptive effect against postincision pain in rats. PMID:27555225

  2. 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.

  3. Role of Frontal Alpha Oscillations in Creativity

    PubMed Central

    Lustenberger, Caroline; Boyle, Michael R.; Foulser, A. Alban; Mellin, Juliann M.; Fröhlich, Flavio

    2015-01-01

    Creativity, the ability to produce innovative ideas, is a key higher-order cognitive function that is poorly understood. At the level of macroscopic cortical network dynamics, recent EEG data suggests that cortical oscillations in the alpha frequency band (8 – 12 Hz) are correlated with creative thinking. However, whether alpha oscillations play a fundamental role in creativity has remained unknown. Here we show that creativity is increased by enhancing alpha power using 10 Hz transcranial alternating current stimulation (10Hz-tACS) of the frontal cortex. In a study of 20 healthy participants with a randomized, balanced cross-over design, we found a significant improvement of 7.4% in the Creativity Index measured by the Torrance Test of Creative Thinking, a comprehensive and most frequently used assay of creative potential and strengths. In a second similar study with 20 subjects, 40Hz-tACS was used in instead of 10Hz-tACS to rule out a general “electrical stimulation” effect. No significant change in the Creativity Index was found for such frontal gamma stimulation. Our results suggest that alpha activity in frontal brain areas is selectively involved in creativity; this enhancement represents the first demonstration of specific neuronal dynamics that drive creativity and can be modulated by non-invasive brain stimulation. Our findings agree with the model that alpha recruitment increases with internal processing demands and is involved in inhibitory top-down control, which is an important requirement for creative ideation. PMID:25913062

  4. A 4.8 hour periodicity in the spectra of Cyg X-3

    NASA Technical Reports Server (NTRS)

    Becker, R. H.; Robinson-Saba, J. L.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Serlemitsos, P. J.; Swank, J. H.

    1978-01-01

    The X-ray spectra from three observations of the X-ray binary Cyg X-3 by the cosmic X-ray spectroscopy experiment on OSO can be represented by power-law continua with strong iron line emission. Comparisons of spectra taken within the same observation at various phases of the 4.8 hour period reveal a relative excess of low energy X-ray emission near zero phase (i.e. the minimum) of the 4.8 hour modulation. In addition, the centroid of the line emission is observed to vary in phase with the 4.8 hour cycle. The possibility of persistent thermal X-ray emission from material surrounding the binary system is introduced in an effort to account for the observed effects.

  5. Photometry of the old nova HZ Pup

    NASA Astrophysics Data System (ADS)

    Cassanelli, Tomas; Abbott, Tim

    2016-01-01

    This study of the old nova HZ Pup involved obtaining image data, removing the instrumental signature, performing photometry on the stellar images present, and generating light curves. Relative photometry between the target star and other stars in the image was used to remove atmospheric effects. A periodogram of this light curve shows the historically known periodicity close to 20 minutes. However, other periodicities are also present and it is not clear from the data which are real and which are artifacts of the sampling. These data will be combined with data from other telescopes collected contemporaneously in order to resolve this ambiguity.

  6. Line parameters for ozone hot bands in the 4.8-micron spectral region

    NASA Technical Reports Server (NTRS)

    Camy-Peyret, Claude; Flaud, Jean-Marie; Rinsland, Curtis P.; Smith, Mary Ann H.; Devi, V. Malathy

    1990-01-01

    Line positions, intensities, and lower-state energies have been calculated for nine hot bands of (O-16)3 in the 4.8-micron spectral region using improved spectroscopic parameters deduced in recent high-resolution laboratory studies. The good quality of the hot-band parameters has been verified through comparisons of line-by-line simulations with 0.005/cm-resolution laboratory spectra of ozone. The present work and the line parameters calculated for the main bands by Pickett et al. (1988) provide a complete update of ozone spectroscopic parameters in the 4.8 micron region.

  7. The 4.8 GHz LHC Schottky pick-up system

    SciTech Connect

    Caspers, Fritz; Jimenez, Jose Miguel; Jones, Rhodri Owain; Kroyer, Tom; Vuitton, Christophe; Hamerla, Timothy W.; Jansson, Andreas; Misek, Joel; Pasquinelli, Ralph J.; Seifrid, Peter; Sun, Ding; /Fermilab

    2007-06-01

    The LHC Schottky observation system is based on traveling wave type high sensitivity pickup structures operating at 4.8 GHz. The choice of the structure and operating frequency is driven by the demanding LHC impedance requirements, where very low impedance is required below 2 GHz, and good sensitivity at the selected band at 4.8 GHz. A sophisticated filtering and triple down -mixing signal processing chain has been designed and implemented in order to achieve the specified 100 dB instantaneous dynamic range without range switching. Detailed design aspects for the complete systems and test results without beam are presented and discussed.

  8. Consider the Earth: Environmental Activities for Grades 4-8. Second Edition.

    ERIC Educational Resources Information Center

    Gates, Julie M.

    This book is designed to educate students in grades 4-8 about eight specific aspects of the environment. Activity-oriented experiences for both urban and rural children to gain certain understandings are provided. Concepts addressed include the fact that humans are animals and are living organisms, animals differ from plants in their ability to…

  9. Career Awareness/Exploration Curriculum Kit. Grades 4-8. Program Two.

    ERIC Educational Resources Information Center

    Grimes, Daniel B., Ed.; And Others

    Designed for integration into existing school curriculum, this is the second in a series of five career education curriculum kits for teachers of grades 4-8. Each kit pertains to one of five specified career education program goals. The goal for this curriculum kit is, "The student will acquire knowledge about the world of work." For this goal,…

  10. Career Awareness/Exploration Curriculum Kit. Grades 4-8. Program Five.

    ERIC Educational Resources Information Center

    Grimes, Daniel B., Ed.; And Others

    Designed for integration into existing school curriculum, this is the fifth in a series of five career education curriculum kits for teachers of grades 4-8. Each kit pertains to one of five specified career education program goals. The goal for this curriculum kit is, "The students will develop physical and mental skills related to occupational…

  11. Career Awareness/Exploration Curriculum Kit. Grades 4-8. Program One.

    ERIC Educational Resources Information Center

    Grimes, Daniel B., Ed.; And Others

    Designed for integration into existing school curriculum, this is the first in a series of five career education curriculum kits for teachers of grades 4-8. Each kit pertains to one of five specified career education program goals. The goal for this curriculum kit is, "The student will identify and develop attitudes about the world of work." For…

  12. Career Awareness/Exploration Curriculum Kit. Grades 4-8. Program Three.

    ERIC Educational Resources Information Center

    Grimes, Daniel B., Ed.; And Others

    Designed for integration into existing school curriculum, this is the third in a series of five career education curriculum kits for teachers of grades 4-8. Each kit pertains to one of five specified career education program goals. The goal for this curriculum kit is, "The students will identify their individuality and continue to develop a…

  13. Career Awareness/Exploration Curriculum Kit. Grades 4-8. Program Four.

    ERIC Educational Resources Information Center

    Grimes, Daniel B., Ed.; And Others

    Designed for integration into existing school curriculum, this is the fourth in a series of five career education curriculum kits for teachers of grades 4-8. Each kit pertains to one of five specified career education program goals. The goal for this curriculum kit is, "The students will develop skills in decision making, communicating, and…

  14. 43 CFR 1610.4-8 - Selection of resource management plan.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Selection of resource management plan..., BUDGETING Resource Management Planning § 1610.4-8 Selection of resource management plan. After publication of the draft resource management plan and draft environmental impact statement, the Field...

  15. 30. Photographic copy of construction drawing, dated 11/19/1928, corrected 4/8/1925, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. Photographic copy of construction drawing, dated 11/19/1928, corrected 4/8/1925, in possession of SCIP Office, Coolidge, AZ. United States Indian Service, Irrigation. ELEVATION AND SECTIONS BRIDGE SPAN - San Carlos Irrigation Project, Sacaton Dam & Bridge, Gila River, T4S R6E S12/13, Coolidge, Pinal County, AZ

  16. 28. Photographic copy of construction drawing, dated 3/22/1923, corrected 4/8/1925, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. Photographic copy of construction drawing, dated 3/22/1923, corrected 4/8/1925, in possession of SCIP Office, Coolidge, AZ. United States Indian Service, Irrigation. SECTIONS OF SOUTHSIDE INTAKE - San Carlos Irrigation Project, Sacaton Dam & Bridge, Gila River, T4S R6E S12/13, Coolidge, Pinal County, AZ

  17. 43 CFR 1610.4-8 - Selection of resource management plan.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Selection of resource management plan..., BUDGETING Resource Management Planning § 1610.4-8 Selection of resource management plan. After publication of the draft resource management plan and draft environmental impact statement, the Field...

  18. Teaching Science to English Learners, Grades 4-8. NCBE Program Information Series Guide 11.

    ERIC Educational Resources Information Center

    Fathman, Ann K.; And Others

    This guide is intended to help teachers plan, design, and implement science activities for students learning English as a Second Language (ESL) in grades 4-8, in mainstream science classes, ESL classes, bilingual education programs, and also to help others serving this population. Steps for designing science experiments that integrate language and…

  19. Spontaneous magnetization of the Ising model on a 4-8 lattice

    NASA Astrophysics Data System (ADS)

    Lin, K. Y.

    1988-03-01

    Spontaneous magnetization of the Ising model on a 4-8 lattice is derived. The result agrees with the conjecture of Lin, Kao and Chen. Our derivation is closely related to the recent work of Choy and Baxter on the isotropic Union Jack lattice.

  20. Guidelines for Teaching Pre/Non-Literate Speakers of Other Languages, Grades 4-8.

    ERIC Educational Resources Information Center

    Davis, Ann M.; And Others

    A handbook for teachers of English as a second language (ESL) and content area teachers in grades 4-8 working with non-literate and preliterate students is designed to facilitate their entry into ESL instruction and mainstreaming into the regular school program. The handbook contains intensive, sequential guidelines for instruction in basic…

  1. Primary calibration system for vibration transducers from 0.4 Hz to 160 Hz

    NASA Astrophysics Data System (ADS)

    Ferreira, C. D.; Ripper, G. P.; Dias, R. S.; Teixeira, D. B.

    2015-01-01

    This paper presents a system developed at the Vibration Laboratory of Inmetro, which is used for primary calibration of vibration transducers by the fringe counting method. This system includes a vibration exciter, a Michelson interferometer, a data acquisition board, a band-pass filter, a universal counter and a software for measurement automation. It allows the laboratory to perform calibrations in accordance with the international standard ISO 16063-11 in the frequency range from 0.4 Hz to 160 Hz. Some experimental results are presented herein.

  2. Resting-state alpha in autism spectrum disorder and alpha associations with thalamic volume.

    PubMed

    Edgar, J Christopher; Heiken, Kory; Chen, Yu-Han; Herrington, John D; Chow, Vivian; Liu, Song; Bloy, Luke; Huang, Mingxiong; Pandey, Juhi; Cannon, Katelyn M; Qasmieh, Saba; Levy, Susan E; Schultz, Robert T; Roberts, Timothy P L

    2015-03-01

    Alpha circuits (8-12 Hz), necessary for basic and complex brain processes, are abnormal in autism spectrum disorder (ASD). The present study obtained estimates of resting-state (RS) alpha activity in children with ASD and examined associations between alpha activity, age, and clinical symptoms. Given that the thalamus modulates cortical RS alpha rhythms, associations between thalamic structure and alpha activity were examined. RS magnetoencephalography was obtained from 47 typically-developing children (TDC) and 41 children with ASD. RS alpha activity was measured using distributed source localization. Left and right thalamic volume measurements were also obtained. In both groups, the strongest alpha activity was observed in Calcarine Sulcus regions. In Calcarine regions, only TDC showed the expected association between age and alpha peak frequency. ASD had more alpha activity than TDC in regions bordering the Central Sulcus as well as parietal association cortices. In ASD, whereas greater left Central Sulcus relative alpha activity was associated with higher Social Responsiveness Scale (SRS) scores, greater Calcarine region relative alpha activity was associated with lower SRS scores. Although thalamic volume group differences were not observed, relationships between thalamic volume and Calcarine alpha power were unique to TDC. The present study also identified a failure to shift peak alpha frequency as a function of age in primary alpha-generating areas in children with ASD. Findings suggested that increased RS alpha activity in primary motor and somatosensory as well as parietal multimodal areas-with increased alpha thought to reflect greater inhibition-might impair the ability to identify or interpret social cues. Finally, to our knowledge, this is the first study to report associations between thalamic volume and alpha power, an association observed only in TDC. The lack of thalamic and alpha associations in ASD suggests thalamic contributions to RS alpha

  3. Alpha Thalassemia

    MedlinePlus

    ... an apparently normal individual has a child with hemoglobin H disease or alpha thalassemia minor. It can ... gene on one chromosome 25% 25% 25% 25% hemoglobin H disease there is a 25% chance with ...

  4. Vector Sum Excited Linear Prediction (VSELP) speech coding at 4.8 kbps

    NASA Technical Reports Server (NTRS)

    Gerson, Ira A.; Jasiuk, Mark A.

    1990-01-01

    Code Excited Linear Prediction (CELP) speech coders exhibit good performance at data rates as low as 4800 bps. The major drawback to CELP type coders is their larger computational requirements. The Vector Sum Excited Linear Prediction (VSELP) speech coder utilizes a codebook with a structure which allows for a very efficient search procedure. Other advantages of the VSELP codebook structure is discussed and a detailed description of a 4.8 kbps VSELP coder is given. This coder is an improved version of the VSELP algorithm, which finished first in the NSA's evaluation of the 4.8 kbps speech coders. The coder uses a subsample resolution single tap long term predictor, a single VSELP excitation codebook, a novel gain quantizer which is robust to channel errors, and a new adaptive pre/postfilter arrangement.

  5. SDSS J094604.90+183541.8: A GRAVITATIONALLY LENSED QUASAR AT z = 4.8

    SciTech Connect

    McGreer, Ian D.; Fan Xiaohui; Bian Fuyan; Farnsworth, Kara; Hall, Patrick B.; Inada, Naohisa; Oguri, Masamune; Strauss, Michael A.; Schneider, Donald P.

    2010-08-15

    We report the discovery of a gravitationally lensed quasar identified serendipitously in the Sloan Digital Sky Survey (SDSS). The object, SDSS J094604.90+183541.8, was initially targeted for spectroscopy as a luminous red galaxy, but the SDSS spectrum has the features of both a z = 0.388 galaxy and a z = 4.8 quasar. We have obtained additional imaging that resolves the system into two quasar images separated by 3.''06 and a bright galaxy that is strongly blended with one of the quasar images. We confirm spectroscopically that the two quasar images represent a single-lensed source at z = 4.8 with a total magnification of 3.2, and we derive a model for the lensing galaxy. This is the highest redshift lensed quasar currently known. We examine the issues surrounding the selection of such an unusual object from existing data and briefly discuss implications for lensed quasar surveys.

  6. RNA polymerase I–Rrn3 complex at 4.8 Å resolution

    PubMed Central

    Engel, Christoph; Plitzko, Jürgen; Cramer, Patrick

    2016-01-01

    Transcription of ribosomal DNA by RNA polymerase I (Pol I) requires the initiation factor Rrn3. Here we report the cryo-EM structure of the Pol I–Rrn3 complex at 4.8 Å resolution. The structure reveals how Rrn3 binding converts an inactive Pol I dimer into an initiation-competent monomeric complex and provides insights into the mechanisms of Pol I-specific initiation and regulation. PMID:27418309

  7. RNA polymerase I-Rrn3 complex at 4.8 Å resolution.

    PubMed

    Engel, Christoph; Plitzko, Jürgen; Cramer, Patrick

    2016-01-01

    Transcription of ribosomal DNA by RNA polymerase I (Pol I) requires the initiation factor Rrn3. Here we report the cryo-EM structure of the Pol I-Rrn3 complex at 4.8 Å resolution. The structure reveals how Rrn3 binding converts an inactive Pol I dimer into an initiation-competent monomeric complex and provides insights into the mechanisms of Pol I-specific initiation and regulation. PMID:27418309

  8. 4.8 Dose to Embryo and Foetuses in Diagnostic Nuclear Medicine

    NASA Astrophysics Data System (ADS)

    Noßke, D.; Mattsson, S.; Johansson, L.

    This document is part of Subvolume A 'Fundamentals and Data in Radiobiology, Radiation Biophysics, Dosimetry and Medical Radiological Protection' of Volume 7 'Medical Radiological Physics' of Landolt-Börnstein - Group VIII 'Advanced Materials and Technologies'. It contains the Section '4.8 Dose to Embryo and Foetuses in Diagnostic Nuclear Medicine' of the Chapter '4 Dosimetry in Nuclear Medicine Diagnosis and Therapy' with the contents:

  9. RNA polymerase I-Rrn3 complex at 4.8 Å resolution

    NASA Astrophysics Data System (ADS)

    Engel, Christoph; Plitzko, Jürgen; Cramer, Patrick

    2016-07-01

    Transcription of ribosomal DNA by RNA polymerase I (Pol I) requires the initiation factor Rrn3. Here we report the cryo-EM structure of the Pol I-Rrn3 complex at 4.8 Å resolution. The structure reveals how Rrn3 binding converts an inactive Pol I dimer into an initiation-competent monomeric complex and provides insights into the mechanisms of Pol I-specific initiation and regulation.

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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.

  16. Synthesis of 2,4,8,10-tetroxaspiro5,5undecane

    NASA Technical Reports Server (NTRS)

    Poshkus, A. C. (Inventor)

    1985-01-01

    Pentaerythritol is converted to its diformal, 2,4,8,10-tetroxaspirol5.5undecane, by heating it to a temperature within the range of about 110 to 150 C, for a period of up to 10 minutes, in the presence of a slight excess of paraformaldehyde and of a catalytic quantity of an acid catalyst such as sulfuric acid. The reaction may be carried out in two steps, by forming first the monoformal, then the diformal. In any case, total reaction time is about 10 minutes, and yield of diformal are greater than 90%. Previous processes require hours or days, and often, tedious operating procedures.

  17. Use of booster seats by Michigan children 4-8 years of age.

    PubMed

    Eby, David W; Bingham, C Raymond; Vivoda, Jonathon M; Ragunathan, Trivellore

    2005-11-01

    This study reports the results of a statewide survey of restraint use by 4-8-year-old children in Michigan conducted between July 13 and 29, 2004. In this study, 3420 4-8-year-old children were observed traveling in passenger cars, vans/minivans, sport-utility vehicles, and pickup trucks. Restraint use was estimated for children traveling in all vehicles combined, as well as for each vehicle type separately. Children's restraint use was also calculated by the sex, age, and belt use of the driver. Separate estimates were also made of the restraint use of 4-8-year-old children by the combination of sex and belt use of the driver. Overall, 8.6 +/- 5.9% of 4-8-year-old children were seated in a booster seat, 48.8 +/- 10.3% were wearing a safety belt, 5.1 +/- 3.4% were seated in a child safety seat, and the remaining 37.5 +/- 11.5% were traveling completely unrestrained. When examining the rates by vehicle type, booster seat use was highest among children riding in sport-utility vehicles and lowest for those in pickup trucks. Surprisingly, children riding in passenger cars were more likely to be completely unrestrained than those in any other type of vehicle. While the sex of the driver did not seem to influence the restraint use of target-aged children, the driver's age did seem to have an effect. Booster seat use was quite low (0.6%) for children traveling with a driver over the age of 60, compared to 7.0 and 9.1% for those riding with drivers 16-29 and 30-59 years of age, respectively. The safety belt use of the driver also had a substantial influence on children's restraint use. Irrespective of driver sex, children riding with belted drivers were traveling in booster seats about 10% of the time, while those riding with unbelted drivers were only in booster seats 1-2% of the time. PMID:16054103

  18. Multiscale magnetosheath turbulence model from mHz to kHz

    NASA Astrophysics Data System (ADS)

    Dwivedi, Navin; Narita, Yasuhito

    2015-04-01

    We construct a nonlinear whistler wave model under the influence of the ponderomotive force to explain the energy spectra and the waveforms observed in loin roar waves in Earth's magnetosheath region. We use the two-fluid approach to derive the model equations governing the dynamics of ion-acoustic and whistler waves propagating along the ambient magnetic field. On the account of ponderomotive force, nonlinearity arises in the dynamics of ion-acoustic wave which modify the background number density under the steady state condition. Whistler wave nonlinearly interacts with the ion-acoustic wave while propagating through the density inhomogeneity created by the ponderomotive force, and gets modulated and forms localized structures in the magnetic field. Furthermore, we develop a semi-analytical numerical method to compute the magnetic energy spectrum of whistler wave and investigate the spectral features of the spectrum. The magnetic field spectrum shows a spectral break accompanied by the steepening of the spectrum with a spectral index -3.2 at higher wave numbers. In the recent past, the magnetic field fluctuations with the occurrence of lion roar waves are widely investigated in the frequency range from 20 to 1000 Hz in Earth's magnetosheath. The observed lion roar waves show a broadband turbulence spectrum with the spectral slope about -4.5. The present model develop a concept on multiscale magnetosheath turbulence in which turbulence at low frequencies (mHz) is dominated by mirror mode, however at high frequencies (kHz) it is mainly due to the nonlinear whistler waves and the whistler turbulence is embedded inside the mirror mode.

  19. Alpha-1 Antitrypsin Deficiency

    MedlinePlus

    ... Liver Disease Information > Alpha-1 Antitrypsin Deficiency Alpha-1 Antitrypsin Deficiency Explore this section to learn more about alpha-1 antitrypsin deficiency, including a description of the disorder ...

  20. Design studies for the LCLS 120 Hz RF gun

    SciTech Connect

    Wang, X.J.; Babzien, M.; Ben-Zvi, I.; Chang, X.Y.; Pjerov, S.; Woodle, M.

    2000-11-01

    A preliminary design studies were carried out at Brookhaven National Laboratory for a photocathode RF gun injection system for LCLS 120 Hz operation. The starting point for the design is 50 Hz BNL Gun IV developed by a BNL/KEK/SHI collaboration. The basic parameters of the 120 Hz gun is discussed in this report. The complete photocathode RF gun injection system is described for a 120 Hz operation. The injector system includes photocathode RF gun, emittance compensation solenoid magnet, laser system and laser beam delivery system, and electron beam diagnostics. The basic design parameters, mechanical modification and the performance will be presented in this report.

  1. 44 CFR 4.8 - How does the Administrator provide an opportunity to comment on proposed Federal financial...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false How does the Administrator provide an opportunity to comment on proposed Federal financial assistance and direct Federal development? 4.8 Section 4.8 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY...

  2. Absolute line intensities in CO2 bands near 4.8 microns

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Benner, D. C.; Devi, V. M.

    1986-01-01

    Absolute intensities for 726 unblended lines in 20 bands of C-12(O-16)2, C-13(O-16)2, O-16C-12O-18, and O-16C-12O-17 in the 4.8-micron spectral region have been determined using a natural sample of ultrahigh-purity CO2. Spectral data were recorded at low pressure (less than 10 torr) and room temperature with the Fourier transform spectrometer in the McMath solar telescope complex on Kitt Peak. Derived vibrational band intensities and coefficients of the F factor for each band were compared to values of the 1982 Air Force Geophysics Laboratory line parameters compilation. The present work fills out the CO2 lines in the 5-micron band systems. Lines in the strongest of these measured bands are being used to infer atmospheric pressure from high-resolution stratospheric spectra recorded during the Spacelab 3 Atmospheric Trace Molecule Spectroscopy experiment.

  3. Large Binocular Telescope Observations of Europa Occulting Io's Volcanoes at 4.8 μm

    NASA Astrophysics Data System (ADS)

    Skrutskie, Michael F.; Conrad, Albert; Resnick, Aaron; Leisenring, Jarron; Hinz, Phil; de Pater, Imke; de Kleer, Katherine; Spencer, John; Skemer, Andrew; Woodward, Charles E.; Davies, Ashley Gerard; Defrére, Denis

    2015-11-01

    On 8 March 2015 Europa passed nearly centrally in front of Io. The Large Binocular Telescope observed this event in dual-aperture AO-corrected Fizeau interferometric imaging mode using the mid-infrared imager LMIRcam operating behind the Large Binocular Telescope Interferometer (LBTI) at a broadband wavelength of 4.8 μm (M-band). Occultation light curves generated from frames recorded every 123 milliseconds show that both Loki and Pele/Pillan were well resolved. Europa's center shifted by 2 kilometers relative to Io from frame-to-frame. The derived light curve for Loki is consistent with the double-lobed structure reported by Conrad et al. (2015) using direct interferometric imaging with LBTI.

  4. Observation of gamma rays with a 4.8 hour periodicity from CYG X-3

    NASA Technical Reports Server (NTRS)

    Lamb, R. C.; Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.; Thompson, D. J.

    1976-01-01

    Energetic (E35 MeV) Gamma rays were observed from Cyg X-3 with the SAS-2 Gamma ray telescope. They are modulated at the 4.8 sup h period observed in the X-ray and infrared regions, and within the statistical error are in phase with this emission. The flux above 100 MeV has an average value of (4.4 + or - 1.1)x 10 to the -6 power/sq cm/sec. If the distance to Cyg X-3 is 10 kpcs, this flux implies a luminosity of more than 10 to the 37th power ergs/s if the radiation is isotropic and about 10 to the 36th power ergs/s if the radiation is restricted to a cone of one steradian, as it might be in a pulsar.

  5. Design of a 4.8-m ring for inverse Compton scattering x-ray source

    NASA Astrophysics Data System (ADS)

    Xu, H. S.; Huang, W. H.; Tang, C. X.; Lee, S. Y.

    2014-07-01

    In this paper we present the design of a 50 MeV compact electron storage ring with 4.8-meter circumference for the Tsinghua Thomson scattering x-ray source. The ring consists of four dipole magnets with properly adjusted bending radii and edge angles for both horizontal and vertical focusing, and a pair of quadrupole magnets used to adjust the horizontal damping partition number. We find that the dynamic aperture of compact storage rings depends essentially on the intrinsic nonlinearity of the dipole magnets with small bending radius. Hamiltonian dynamics is found to agree well with results from numerical particle tracking. We develop a self-consistent method to estimate the equilibrium beam parameters in the presence of the intrabeam scattering, synchrotron radiation damping, quantum excitation, and residual gas scattering. We also optimize the rf parameters for achieving a maximum x-ray flux.

  6. LARP LHC 4.8 GHZ Schottky System Initial Commissioning with Beam

    SciTech Connect

    Pasquinelli, Ralph J.; Jansson, Andreas; Jones, O.Rhodri; Caspers, Fritz; /CERN

    2011-03-18

    The LHC Schottky system consists for four independent 4.8 GHz triple down conversion receivers with associated data acquisition systems. Each system is capable of measuring tune, chromaticity, momentum spread in either horizontal or vertical planes; two systems per beam. The hardware commissioning has taken place from spring through fall of 2010. With nominal bunch beam currents of 10{sup 11} protons, the first incoherent Schottky signals were detected and analyzed. This paper will report on these initial commissioning results. A companion paper will report on the data analysis curve fitting and remote control user interface of the system. The Schottky system for the LHC was proposed in 2004 under the auspices of the LARP collaboration. Similar systems were commissioned in 2003 in the Fermilab Tevatron and Recycler accelerators as a means of measuring tunes noninvasively. The Schottky detector is based on the stochastic cooling pickups that were developed for the Fermilab Antiproton Source Debuncher cooling upgrade completed in 2002. These slotted line waveguide pickups have the advantage of large aperture coupled with high beam coupling characteristics. For stochastic cooling, wide bandwidths are integral to cooling performance. The bandwidth of slotted waveguide pickups can be tailored by choosing the length of the pickup and slot spacing. The Debuncher project covered the 4-8 GHz band with eight bands of pickups, each with approximately 500 MHz of bandwidth. For use as a Schottky detector, bandwidths of 100-200 MHz are required for gating, resulting in higher transfer impedance than those used for stochastic cooling. Details of hardware functionality are reported previously.

  7. Morphological analysis on the coherence of kHz QPOs

    NASA Astrophysics Data System (ADS)

    Wang, J.; Chang, H. K.; Zhang, C. M.; Wang, D. H.; Chen, L.; Qu, J. L.; Song, L. M.

    2012-12-01

    We take the recently published data of twin kHz quasi-period oscillations (QPOs) in neutron star (NS) low-mass X-ray binaries (LMXBs) as the samples, and investigate the morphology of the samples, which focuses on the quality factor, peak frequency of kHz QPOs, and try to infer their physical mechanism. We notice that: (1) The quality factors of upper kHz QPOs are low (2˜20 in general) and increase with the kHz QPO peak frequencies for both Z and Atoll sources. (2) The distribution of quality factor versus frequency for the lower kHz QPOs are quite different between Z and Atoll sources. For most Z source samples, the quality factors of lower kHz QPOs are low (usually lower than 15) and rise steadily with the peak frequencies except for Sco X-1, which drop abruptly at the frequency of about 750 Hz. While for most Atoll sources, the quality factors of lower kHz QPOs are very high (from 2 to 200) and usually have a rising part, a maximum and an abrupt drop. (3) There are three Atoll sources (4U 1728-34, 4U 1636-53 and 4U 1608-52) of displaying very high quality factors for lower kHz QPOs. These three sources have been detected with the spin frequencies and sidebands, in which the source with higher spin frequency presents higher quality factor of lower kHz QPOs and lower difference between sideband frequency and lower kHz QPO frequency.

  8. Reduced Variability of Auditory Alpha Activity in Chronic Tinnitus

    PubMed Central

    Schecklmann, Martin; Kreuzer, Peter M.; Vielsmeier, Veronika; Poeppl, Timm B.; Langguth, Berthold

    2014-01-01

    Subjective tinnitus is characterized by the conscious perception of a phantom sound which is usually more prominent under silence. Resting state recordings without any auditory stimulation demonstrated a decrease of cortical alpha activity in temporal areas of subjects with an ongoing tinnitus perception. This is often interpreted as an indicator for enhanced excitability of the auditory cortex in tinnitus. In this study we want to further investigate this effect by analysing the moment-to-moment variability of the alpha activity in temporal areas. Magnetoencephalographic resting state recordings of 21 tinnitus subjects and 21 healthy controls were analysed with respect to the mean and the variability of spectral power in the alpha frequency band over temporal areas. A significant decrease of auditory alpha activity was detected for the low alpha frequency band (8–10 Hz) but not for the upper alpha band (10–12 Hz). Furthermore, we found a significant decrease of alpha variability for the tinnitus group. This result was significant for the lower alpha frequency range and not significant for the upper alpha frequencies. Tinnitus subjects with a longer history of tinnitus showed less variability of their auditory alpha activity which might be an indicator for reduced adaptability of the auditory cortex in chronic tinnitus. PMID:24967106

  9. Star formation and black hole growth at z ≅ 4.8

    SciTech Connect

    Netzer, Hagai; Mor, Rivay; Trakhtenbrot, Benny; Shemmer, Ohad; Lira, Paulina

    2014-08-10

    We report Herschel/SPIRE, Spitzer and Wide-field Infrared Survey Explorer observations of 44 z ≅ 4.8 optically selected active galactic nuclei (AGNs). This flux-limited sample contains the highest mass black holes (BHs) at this redshift. Ten of the objects were detected by Herschel and five show emission that is not clearly associated with the AGNs. The star formation (SF) luminosity (L{sub SF}) obtained by fitting the spectral energy distribution (SED) with standard SF templates, taking into account AGN contribution, is in the range 10{sup 46.62}-10{sup 47.21} erg s{sup –1} corresponding to SF rates of 1090-4240 M{sub ☉} yr{sup –1}. Fitting with very luminous submillimeter galaxy SEDs gives SF rates that are smaller by 0.05 dex when using all bands and 0.1 dex when ignoring the 250 μm band. A 40 K graybody fits to only the 500 μm fluxes reduce L{sub SF} by about a factor of two. A stacking analysis of 29 undetected sources gives significant signals in all three bands. A SF template fit indicates L{sub SF} = 10{sup 46.19-46.23} erg s{sup –1} depending on the assumed AGN contribution. A 40 K fit to the stacked 500 μm flux gives L{sub SF} = 10{sup 45.95} erg s{sup –1}. The mean BH mass (M{sub BH}) and AGN luminosity (L{sub AGN}) of the detected sources are significantly higher than those of the undetected ones. The spectral differences are seen all the way from UV to far infrared wavelengths. The mean optical-UV spectra are similar to those predicted for thin accretion disks around BHs with similar masses and accretion rates. We suggest two alternative explanations to the correlation of L{sub SF}, L{sub AGN} and M{sub BH}, one involving no AGN feedback and the second involving moderate feedback that affects, but does not totally quench, SF in three-quarters of the sources. We compare our L{sub SF} and L{sub AGN} to lower redshift samples and show a new correlation between L{sub SF} and M{sub BH}. We also examine several rather speculative ideas about

  10. Star Formation and Black Hole Growth at z ~= 4.8

    NASA Astrophysics Data System (ADS)

    Netzer, Hagai; Mor, Rivay; Trakhtenbrot, Benny; Shemmer, Ohad; Lira, Paulina

    2014-08-01

    We report Herschel/SPIRE, Spitzer and Wide-field Infrared Survey Explorer observations of 44 z ~= 4.8 optically selected active galactic nuclei (AGNs). This flux-limited sample contains the highest mass black holes (BHs) at this redshift. Ten of the objects were detected by Herschel and five show emission that is not clearly associated with the AGNs. The star formation (SF) luminosity (L SF) obtained by fitting the spectral energy distribution (SED) with standard SF templates, taking into account AGN contribution, is in the range 1046.62-1047.21 erg s-1 corresponding to SF rates of 1090-4240 M ⊙ yr-1. Fitting with very luminous submillimeter galaxy SEDs gives SF rates that are smaller by 0.05 dex when using all bands and 0.1 dex when ignoring the 250 μm band. A 40 K graybody fits to only the 500 μm fluxes reduce L SF by about a factor of two. A stacking analysis of 29 undetected sources gives significant signals in all three bands. A SF template fit indicates L SF = 1046.19-46.23 erg s-1 depending on the assumed AGN contribution. A 40 K fit to the stacked 500 μm flux gives L SF = 1045.95 erg s-1. The mean BH mass (M BH) and AGN luminosity (L AGN) of the detected sources are significantly higher than those of the undetected ones. The spectral differences are seen all the way from UV to far infrared wavelengths. The mean optical-UV spectra are similar to those predicted for thin accretion disks around BHs with similar masses and accretion rates. We suggest two alternative explanations to the correlation of L SF, L AGN and M BH, one involving no AGN feedback and the second involving moderate feedback that affects, but does not totally quench, SF in three-quarters of the sources. We compare our L SF and L AGN to lower redshift samples and show a new correlation between L SF and M BH. We also examine several rather speculative ideas about the host galaxy properties including the possibility that the detected sources are above the SF mass sequence (MS) at z ~= 4.8

  11. Was the Timpson, Texas, M4.8 event induced by fluid injection?

    NASA Astrophysics Data System (ADS)

    Fan, Z.; Eichhubl, P.; Gale, J.; Olson, J. E.; Frohlich, C.; Gono, V.

    2014-12-01

    A M4.8 earthquake with dominant strike-slip near Timpson, east Texas, the largest documented earthquake to date in that region, has received extensive attention due to the possible linkage to waste water injection. The reliably located aftershocks align along a previously mapped fault striking about N42°W. Two active injection wells are located within 3 km of the aftershocks. One injection well became operational in August 2006 with an average injection rate of 42,750 m3/mo at an average pumping pressure of 12.4 MPa at depths between 1853 and 1868 m. Six months later, the second well started injection at 15,600 m3/mo. To investigate the causative relationship between fluid injection and possibly induced seismic fault slip, we integrated geologic and geophysical data into a poroelastic finite element model to simulate the spatial and temporal evolution of pore pressure and stress fields and analyze the stability of fault by applying the Coulomb failure criterion. Parametric studies were performed to analyze the sensitivity of Coulomb failure stress to the variability of input parameters including permeability of injection layer, fault orientation and permeability, and orientation and magnitude of stress state prior to injection. Assuming a Byerlee friction coefficient of 0.6, and using best available estimates of layer permeability, fault orientation, and stress tensor orientation and magnitude, we calculated fault slip occurs 55 months after the start of injection in the model, close to the observed delay of 69 months between injection and the M4.8 event. However, even with principal stress directions and fault orientation being reasonably well constrained, Coulomb failure stress is highly sensitive to input parameters resulting in large uncertainties in correlating injection rate and volume with the onset of induced seismic events. In addition, injection layer and fault zone permeability has a profound effect on the pore pressure evolution. These results

  12. A 4.8 kbps code-excited linear predictive coder

    NASA Technical Reports Server (NTRS)

    Tremain, Thomas E.; Campbell, Joseph P., Jr.; Welch, Vanoy C.

    1988-01-01

    A secure voice system STU-3 capable of providing end-to-end secure voice communications (1984) was developed. The terminal for the new system will be built around the standard LPC-10 voice processor algorithm. The performance of the present STU-3 processor is considered to be good, its response to nonspeech sounds such as whistles, coughs and impulse-like noises may not be completely acceptable. Speech in noisy environments also causes problems with the LPC-10 voice algorithm. In addition, there is always a demand for something better. It is hoped that LPC-10's 2.4 kbps voice performance will be complemented with a very high quality speech coder operating at a higher data rate. This new coder is one of a number of candidate algorithms being considered for an upgraded version of the STU-3 in late 1989. The problems of designing a code-excited linear predictive (CELP) coder to provide very high quality speech at a 4.8 kbps data rate that can be implemented on today's hardware are considered.

  13. A 3.1-4.8 GHz CMOS receiver for MB-OFDM UWB

    NASA Astrophysics Data System (ADS)

    Guang, Yang; Wang, Yao; Jiangwei, Yin; Renliang, Zheng; Wei, Li; Ning, Li; Junyan, Ren

    2009-01-01

    An integrated fully differential ultra-wideband CMOS receiver for 3.1-4.8 GHz MB-OFDM systems is presented. A gain controllable low noise amplifier and a merged quadrature mixer are integrated as the RF front-end. Five order Gm-C type low pass filters and VGAs are also integrated for both I and Q IF paths in the receiver. The ESD protected chip is fabricated in a Jazz 0.18 μm RF CMOS process and achieves a maximum total voltage gain of 65 dB, an AGC range of 45 dB with about 6 dB/step, an averaged total noise figure of 6.4 to 8.8 dB over 3 bands and an in-band IIP3 of -5.1 dBm. The receiver occupies 2.3 mm2 and consumes 110 mA from a 1.8 V supply including test buffers and a digital module.

  14. Familial Constitutional Rearrangement of Chromosomes 4 & 8: Phenotypically Normal Mother and Abnormal Progeny

    PubMed Central

    Kunwar, Fulesh

    2016-01-01

    Balanced chromosome translocations carriers mostly do not have recognizable phenotypic expression but may have more risk of recurrent spontaneous abortions &/or children with serious birth defects due to unbalanced chromosome complements. Unbalanced chromosomal rearrangements have variable clinical expression and are rare. We present here a case report of three siblings affected with intellectual disability and minor dysmorphic features of face and limbs, born to a non-consanguineous couple in which mother had 5 abortions. The constitutional chromosome analysis revealed balanced translocation t (4;8) in mother and all the three siblings were karyotypically normal. Chromosomal microarray in one of the probands revealed partial monosomy 8pter-p23 and a partial trisomy 4pter-p16. Phenotypic features were recorded in 3 probands using Human Phenotype Ontology terms to query web-based tool Phenomizer. The harmonized description using globally accepted ontology is very important especially in case of rare genetic conditions and the heterogeneous phenotypes which make it even more challenging. The prevalence of sub-microscopic unbalanced translocations may be under-reported due to lesser use of molecular genetic analysis. The familial expression of abnormal phenotypes including intellectual disability make the individuals candidate for molecular genetic analysis and phenotyping to help defer the status of idiopathic mental retardation and identify sub-entity of genetic condition. PMID:27190830

  15. Detection of Nitro aromatics via fluorescence quenching of pegylated and siloxanated 4, 8-dimethylcoumarins

    NASA Astrophysics Data System (ADS)

    Kumar, Abhishek; Pandey, Mukesh; Kumar, Jayant

    2011-03-01

    There is considerable interest in developing chemical sensors for detection of trace explosives. Optical sensors, which rely on the change in optical properties of the material, proved to be very effective. Therefore, there is a need to develop materials for optical sensors which can interact specifically with analytes and detect them sensitively. Here, we report the synthesis of co-polymers of 4, 8-dimethylcoumarins with poly (ethylene glycol) (PEG) and polydimethylsiloxane (PDMS) using Candida Antarctica lipase as a catalyst under solvent-less condition. The low Tg of PEG and PDMS may facilitate porous structure in solid films which allows quencher molecules to easily diffuse in and out of these films. In addition, the co-polymers prevent aggregation and lend themselves easily for thin film fabrication which otherwise is difficult because of low molecular weight of coumarin. Fluorescence quenching of these co-polymer in presence of nitro aromatics, 2,4-dinitrotoulne and 2,4,6-trinitrotoluene, in solution and in vapor phase will be reported. National Science Foundation.

  16. The 2009 earthquake, magnitude mb 4.8, in the Pantanal Wetlands, west-central Brazil.

    PubMed

    Dias, Fábio L; Assumpção, Marcelo; Facincani, Edna M; França, George S; Assine, Mario L; Paranhos, Antônio C; Gamarra, Roberto M

    2016-09-01

    The main goal of this paper is to characterize the Coxim earthquake occurred in June 15th, 2009 in the Pantanal Basin and to discuss the relationship between its faulting mechanism with the Transbrasiliano Lineament. The earthquake had maximum intensity MM V causing damage in farm houses and was felt in several cities located around, including Campo Grande and Goiânia. The event had an mb 4.8 magnitude and depth was 6 km, i.e., it occurred in the upper crust, within the basement and 5 km below the Cenozoic sedimentary cover. The mechanism, a thrust fault mechanism with lateral motion, was obtained by P-wave first-motion polarities and confirmed by regional waveform modelling. The two nodal planes have orientations (strike/dip) of 300°/55° and 180°/55° and the orientation of the P-axis is approximately NE-SW. The results are similar to the Pantanal earthquake of 1964 with mb 5.4 and NE-SW compressional axis. Both events show that Pantanal Basin is a seismically active area, under compressional stress. The focal mechanism of the 1964 and 2009 events have no nodal plane that could be directly associated with the main SW-NE trending Transbrasiliano system indicating that a direct link of the Transbrasiliano with the seismicity in the Pantanal Basin is improbable. PMID:27580359

  17. The ANGPTL3-4-8 model, a molecular mechanism for triglyceride trafficking

    PubMed Central

    Zhang, Ren

    2016-01-01

    Lipoprotein lipase (LPL) is a rate-limiting enzyme for hydrolysing circulating triglycerides (TG) into free fatty acids that are taken up by peripheral tissues. Postprandial LPL activity rises in white adipose tissue (WAT), but declines in the heart and skeletal muscle, thereby directing circulating TG to WAT for storage; the reverse is true during fasting. However, the mechanism for the tissue-specific regulation of LPL activity during the fed–fast cycle has been elusive. Recent identification of lipasin/angiopoietin-like 8 (Angptl8), a feeding-induced hepatokine, together with Angptl3 and Angptl4, provides intriguing, yet puzzling, insights, because all the three Angptl members are LPL inhibitors, and the deficiency (overexpression) of any one causes hypotriglyceridaemia (hypertriglyceridaemia). Then, why does nature need all of the three? Our recent data that Angptl8 negatively regulates LPL activity specifically in cardiac and skeletal muscles suggest an Angptl3-4-8 model: feeding induces Angptl8, activating the Angptl8–Angptl3 pathway, which inhibits LPL in cardiac and skeletal muscles, thereby making circulating TG available for uptake by WAT, in which LPL activity is elevated owing to diminished Angptl4; the reverse is true during fasting, which suppresses Angptl8 but induces Angptl4, thereby directing TG to muscles. The model suggests a general framework for how TG trafficking is regulated. PMID:27053679

  18. Auditory filter shapes at 8 and 10 kHz.

    PubMed

    Shailer, M J; Moore, B C; Glasberg, B R; Watson, N; Harris, S

    1990-07-01

    Auditory filter shapes were derived from notched-noise masking data at center frequencies of 8 kHz (for three spectrum levels, N0 = 20, 35, and 50 dB) and 10 kHz (N0 = 50 dB). In order to minimize variability due to earphone placement, insert earphones (Etymotic Research ER2) were used and individual earmolds were made for each subject. These earphones were designed to give a flat frequency response at the eardrum for frequencies up to 14 kHz. The filter shapes were derived under the assumption that a frequency-dependent attenuation was applied to all stimuli before reaching the filter; this attenuation function was estimated from the variation of absolute threshold with frequency for the three youngest normally hearing subjects in our experiments. At 8 kHz, the mean equivalent rectangular bandwidths (ERBs) of the filters derived from the individual data for three subjects were 677, 637, and 1011 Hz for N0 = 20, 35, and 50 dB, respectively. The filters at N0 = 50 dB were roughly symmetrical, while, at the lower spectrum levels, the low-frequency skirt was steeper than the high-frequency skirt. The mean ERB at 10 kHz was 957 Hz. At this frequency, the filters for two subjects were steeper on the high-frequency side than the low-frequency side, while the third subject showed a slight asymmetry in the opposite direction. PMID:2380442

  19. Purification of a 53kD pI 4. 8 cytosolic phosphoprotein from HL60

    SciTech Connect

    Biser, P.S.; Spearman, T.N.; Bruzzone, M.; Durham, J.P.

    1987-05-01

    In order to study the potential role of a 53kD pI 4.8 phosphoprotein in the differentiation of HL60 using monoclonal antibodies, a partial purification has been carried out. Cytosol from cells differentiated with 1 M retinoic acid was applied to a DEAE-cellulose column and eluted with a linear NaCl gradient. Fractions were screened by in vitro phosphorylation of aliquots using /sup 32/P ATP and highly purified protein kinase C, SDS-PAGE, and autoradiography. Fraction which showed autoradiographic bands of the correct molecular weight were further analyzed using 2-D electrophoresis involving isolectric focusing over a pH range of 4-6 followed by SDS-PAGE on a 10% slab gel. Autoradiograms of these gels showed the 53 kD pI 4.8 phosphoprotein to elute with a peak at 0.24 NaCl. This 53 kD pI 4.8 protein was identified as the 53kD pI 4.8 phosphoprotein whose synthesis and phosphorylation is induced by retinoic acid by DEAE chromatography of cytosol from cells labelled in vivo with /sup 32/PO/sub 4//sup -2/ followed by 2-D electrophoresis. Fractions containing the 53 kD pI 4.8 protein were concentrated and applied to a chromatofocusing column which was eluted with a gradient from pH 6 to 4. Analysis of fractions via in vitro phosphorylation and SDS PAGE showed the 53 kD pI 4.8 protein eluting with a peak at pH 4.8 as a silver-stained band well separated from contaminating proteins. Experiments are currently in progress to produce monoclonal antibodies to the 53 kD pI 4.8 protein using the partially purified antigen.

  20. Real-time optimal adaptation for planetary geometry and texture: 4-8 tile hierarchies.

    PubMed

    Hwa, Lok M; Duchaineau, Mark A; Joy, Kenneth I

    2005-01-01

    The real-time display of huge geometry and imagery databases involves view-dependent approximations, typically through the use of precomputed hierarchies that are selectively refined at runtime. A classic motivating problem is terrain visualization in which planetary databases involving billions of elevation and color values are displayed on PC graphics hardware at high frame rates. This paper introduces a new diamond data structure for the basic selective-refinement processing, which is a streamlined method of representing the well-known hierarchies of right triangles that have enjoyed much success in real-time, view-dependent terrain display. Regular-grid tiles are proposed as the payload data per diamond for both geometry and texture. The use of 4-8 grid refinement and coarsening schemes allows level-of-detail transitions that are twice as gradual as traditional quadtree-based hierarchies, as well as very high-quality low-pass filtering compared to subsampling-based hierarchies. An out-of-core storage organization is introduced based on Sierpinski indices per diamond, along with a tile preprocessing framework based on fine-to-coarse, same-level, and coarse-to-fine gathering operations. To attain optimal frame-to-frame coherence and processing-order priorities, dual split and merge queues are developed similar to the Realtime Optimally Adapting Meshes (ROAM) Algorithm, as well as an adaptation of the ROAM frustum culling technique. Example applications of lake-detection and procedural terrain generation demonstrate the flexibility of the tile processing framework. PMID:16138547

  1. Extension of 4-8 Texture Hierarchies to Large Video Processing and Visualization

    SciTech Connect

    Senecal, J G; Wegner, A E

    2007-11-30

    The purpose of this Techbase was to reduce to practice the tiled 4-8 texture hierarchy for the display of video imagery (i.e. sequences of frames). The immediate intent was to demonstrate its use in the analysis and display of sensor imagery. As sensors are increasing in resolution the physical amount of imagery that needs to be displayed can quickly overwhelm most display systems. For example, a sensor with a horizontal resolution of over 8000 pixels would generate an image over 10 feet wide on a standard 72 DPI display. Breaking an image into tiles, and then decomposing each tile into a multiresolution hierarchy, allows a user (or software) to efficiently select and display only those parts of the image that are of interest to the user. The originator of the idea of 4-8 Texture Hierarchies was Dr. Mark Duchaineau, and we consulted with him in much of our work. We also consulted with Dan Knight, from SequoiaTek Corp., who is a contractor responsible for implementing the viewers for our applications. Most of the code for actual 4-8 Texture Hierarchy generation already existed; a large focus of the Techbase was to determine how to best use what was available for video imagery. The majority of progress was made in specifying and implementing the software framework, which turned out to be rather involved. This framework is to support the creation, storage, and display of images, both tiled and untiled. A first albeit incomplete version was successfully tested in the field in August 2007. The framework structures the process of collecting and processing images conceptually as a pipeline, where work is passed along and a different operation is performed at each stage. In practice, the pipeline is implemented by a group of processes (not threads), or 'workers', each responsible for a specific type of operation. Associated with these workers is a pool of memory (cache). As each process finishes its work, it places the results into the cache and sends a message to the

  2. Alpha-1 Antitrypsin Deficiency

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Alpha-1 Antitrypsin Deficiency? Alpha-1 antitrypsin (an-tee-TRIP-sin) deficiency, or AAT ... as it relates to lung disease. Overview Alpha-1 antitrypsin, also called AAT, is a protein made ...

  3. Phytotoxicity of 4,8-dihydroxy-1-tetralone isolated from Carya cathayensis Sarg. to various plant species.

    PubMed

    Li, Xian-Xian; Yu, Min-Feng; Ruan, Xiao; Zhang, Yu-Zhu; Wang, Qiang

    2014-01-01

    The aqueous extract from Carya cathayensis Sarg. exocarp was centrifuged, filtered, and separated into 11 elution fractions by X-5 macroporous resin chromatography. A phenolic compound, 4,8-dihydroxy-1-tetralone (4,8-DHT) was isolated from the fractions with the strongest phytotoxicity by bioassy-guided fractionation, and investigated for phytotoxicity on lettuce (Latuca sativa L.), radish (Raphanus sativus L.), cucumber (Cucumis sativus L.), onion (Allium cepa L.) and wheat (Triticum aestivum L.). The testing results showed that the treatment with 0.6 mM 4,8-DHT could significantly depress the germination vigor of lettuce and wheat, reduce the germination rate of lettuce and cucumber, and also inhibit radicle length, plumule length, and fresh weight of seedlings of lettuce and onion, but could significantly promote plumule length and fresh weight of seedlings of cucumber (p < 0.05). For the tested five plants, the 4,8-DHT was the most active to the seed germination and seedling growth of lettuce, indicating that the phytotoxicity of 4,8-DHT had the selectivity of dosage, action target (plant type) and content (seed germination or seedling growth). PMID:25264832

  4. 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.

  5. 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).

  6. Functional role of frontal alpha oscillations in creativity.

    PubMed

    Lustenberger, Caroline; Boyle, Michael R; Foulser, A Alban; Mellin, Juliann M; Fröhlich, Flavio

    2015-06-01

    Creativity, the ability to produce innovative ideas, is a key higher-order cognitive function that is poorly understood. At the level of macroscopic cortical network dynamics, recent electroencephalography (EEG) data suggests that cortical oscillations in the alpha frequency band (8-12 Hz) are correlated with creative thinking. However, whether alpha oscillations play a functional role in creativity has remained unknown. Here we show that creativity is increased by enhancing alpha power using 10 Hz transcranial alternating current stimulation (10 Hz-tACS) of the frontal cortex. In a study of 20 healthy participants with a randomized, balanced cross-over design, we found a significant improvement of 7.4% in the Creativity Index measured by the Torrance Test of Creative Thinking (TTCT), a comprehensive and most frequently used assay of creative potential and strengths. In a second similar study with 20 subjects, 40 Hz-tACS was used instead of 10 Hz-tACS to rule out a general "electrical stimulation" effect. No significant change in the Creativity Index was found for such frontal 40 Hz stimulation. Our results suggest that alpha activity in frontal brain areas is selectively involved in creativity; this enhancement represents the first demonstration of specific neuronal dynamics that drive creativity and can be modulated by non-invasive brain stimulation. Our findings agree with the model that alpha recruitment increases with internal processing demands and is involved in inhibitory top-down control, which is an important requirement for creative ideation. PMID:25913062

  7. Man and Environment for the Intermediate Grades; A Curriculum Guide for Environmental Studies for Grades 4-8.

    ERIC Educational Resources Information Center

    National Association for Environmental Education, Miami, FL.

    This curriculum guide consists of environmental studies modules for grades 4-8. The curriculum, which is organized around major concepts, is intended to serve as a guide for program development and as a framework for compiling and sharing ideas on methods and application on a national basis. Each module may be utilized as an integral part of the…

  8. Relationship Between Mental Maturity and the Level of Understanding of Concepts of Relativity in Grades 4-8.

    ERIC Educational Resources Information Center

    Haddad, Wadi Dahir

    This study was conducted to (1) identify certain concepts of relativity, and (2) determine the relationship between understanding of these relationships achieved by pupils in grades 4-8 (as indicated by objective test scores) and such variables as grade level and mental ability. Several related sub-problems were also identified. A conceptual…

  9. Behavioral and prenatal effects of 60-Hz fields

    SciTech Connect

    Not Available

    1983-08-01

    Purpose was to determine possible neural, behavioral, and reproductive effects of low-intensity 60-Hz electric fields on mammals (rats) exposed in-utero. The tests used shortly after birth included negative geotaxis, the acoustic startle response, surface righting, in-air righting, cliff avoidance, emotionality, and swimming endurance. Variations between the exposed and control groups are discussed. 9 tables. (DLC)

  10. 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.

  11. Circuit measures hysteresis loop areas at 30 Hz

    NASA Technical Reports Server (NTRS)

    Hoffman, C.; Spilo, D.

    1967-01-01

    Analog circuit measures hysteresis loop areas as a function of time during fatigue testing of specimens subjected to sinusoidal tension-compression stresses at a frequency of Hz. When the sinusoidal stress signal is multiplied by the strain signal, the dc signal is proportional to hysteresis loop area.

  12. EFFECTS OF 60-HZ FIELDS ON HUMAN HEALTH PARAMETERS

    EPA Science Inventory

    Specific results of research on the effects of exposure to 60-Hz electric and magnetic fields have often been contradictory and difficult to replicate. The study reported here used quantitative exercise testing techniques to evaluate whether increases in metabolism, caused by mod...

  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. Somatosensory Anticipatory Alpha Activity Increases to Suppress Distracting Input

    ERIC Educational Resources Information Center

    Haegens, Saskia; Luther, Lisa; Jensen, Ole

    2012-01-01

    Effective processing of sensory input in daily life requires attentional selection and amplification of relevant input and, just as importantly, attenuation of irrelevant information. It has been proposed that top-down modulation of oscillatory alpha band activity (8-14 Hz) serves to allocate resources to various regions, depending on task…

  15. Evidence for genetic regulation of the human parieto-occipital 10-Hz rhythmic activity.

    PubMed

    Salmela, Elina; Renvall, Hanna; Kujala, Jan; Hakosalo, Osmo; Illman, Mia; Vihla, Minna; Leinonen, Eira; Salmelin, Riitta; Kere, Juha

    2016-08-01

    Several functional and morphological brain measures are partly under genetic control. The identification of direct links between neuroimaging signals and corresponding genetic factors can reveal cellular-level mechanisms behind the measured macroscopic signals and contribute to the use of imaging signals as probes of genetic function. To uncover possible genetic determinants of the most prominent brain signal oscillation, the parieto-occipital 10-Hz alpha rhythm, we measured spontaneous brain activity with magnetoencephalography in 210 healthy siblings while the subjects were resting, with eyes closed and open. The reactivity of the alpha rhythm was quantified from the difference spectra between the two conditions. We focused on three measures: peak frequency, peak amplitude and the width of the main spectral peak. In accordance with earlier electroencephalography studies, spectral peak amplitude was highly heritable (h(2)  > 0.75). Variance component-based analysis of 28 000 single-nucleotide polymorphism markers revealed linkage for both the width and the amplitude of the spectral peak. The strongest linkage was detected for the width of the spectral peak over the left parieto-occipital cortex on chromosome 10 (LOD = 2.814, nominal P < 0.03). This genomic region contains several functionally plausible genes, including GRID1 and ATAD1 that regulate glutamate receptor channels mediating synaptic transmission, NRG3 with functions in brain development and HRT7 involved in the serotonergic system and circadian rhythm. Our data suggest that the alpha oscillation is in part genetically regulated, and that it may be possible to identify its regulators by genetic analyses on a realistically modest number of samples. PMID:27306141

  16. Ab initio alpha-alpha scattering

    NASA Astrophysics Data System (ADS)

    Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A.; Luu, Thomas; Meißner, Ulf-G.

    2015-12-01

    Processes such as the scattering of alpha particles (4He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei—nuclei with even and equal numbers of protons and neutrons—is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the ‘adiabatic projection method’ to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of

  17. Ab initio alpha-alpha scattering.

    PubMed

    Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A; Luu, Thomas; Meißner, Ulf-G

    2015-12-01

    Processes such as the scattering of alpha particles ((4)He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei--nuclei with even and equal numbers of protons and neutrons--is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the 'adiabatic projection method' to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of

  18. Seismicity pattern changes before the M = 4.8 Aeolian Archipelago (Italy) earthquake of August 16, 2010.

    PubMed

    Gambino, Salvatore; Laudani, Antonino; Mangiagli, Salvatore

    2014-01-01

    We investigated the seismicity patterns associated with an M = 4.8 earthquake recorded in the Aeolian Archipelago on 16, August, 2010, by means of the region-time-length (RTL) algorithm. This earthquake triggered landslides at Lipari; a rock fall on the flanks of the Vulcano, Lipari, and Salina islands, and some damages to the village of Lipari. The RTL algorithm is widely used for investigating precursory seismicity changes before large and moderate earthquakes. We examined both the spatial and temporal characteristics of seismicity changes in the Aeolian Archipelago region before the M = 4.8 earthquake. The results obtained reveal 6-7 months of seismic quiescence which started about 15 months before the earthquake. The spatial distribution shows an extensive area characterized by seismic quiescence that suggests a relationship between quiescence and the Aeolian Archipelago regional tectonics. PMID:24511288

  19. Seismicity Pattern Changes before the M = 4.8 Aeolian Archipelago (Italy) Earthquake of August 16, 2010

    PubMed Central

    2014-01-01

    We investigated the seismicity patterns associated with an M = 4.8 earthquake recorded in the Aeolian Archipelago on 16, August, 2010, by means of the region-time-length (RTL) algorithm. This earthquake triggered landslides at Lipari; a rock fall on the flanks of the Vulcano, Lipari, and Salina islands, and some damages to the village of Lipari. The RTL algorithm is widely used for investigating precursory seismicity changes before large and moderate earthquakes. We examined both the spatial and temporal characteristics of seismicity changes in the Aeolian Archipelago region before the M = 4.8 earthquake. The results obtained reveal 6-7 months of seismic quiescence which started about 15 months before the earthquake. The spatial distribution shows an extensive area characterized by seismic quiescence that suggests a relationship between quiescence and the Aeolian Archipelago regional tectonics. PMID:24511288

  20. Summaries of the Sixth Annual JPL Airborne Earth Science Workshop, March 4-8, 1996. Volume 2; AIRSAR Workshop

    NASA Technical Reports Server (NTRS)

    Kim, Yunjin (Editor)

    1996-01-01

    This publication contains the summaries for the Sixth Annual JPL Airborne Earth Science Workshop, held in Pasadena, California, on March 4-8, 1996. The main workshop is divided into two smaller workshops as follows: The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) workshop, on March 4-6. The summaries for this workshop appear in Volume 1. The Airborne Synthetic Aperture Radar (AIRSAR) workshop, on March 6-8. The summaries for this workshop appear in Volume 2.

  1. Absolutely calibrated radio polarimetry of the inner Galaxy at 2.3 and 4.8 GHz

    NASA Astrophysics Data System (ADS)

    Sun, X. H.; Gaensler, B. M.; Carretti, E.; Purcell, C. R.; Staveley-Smith, L.; Bernardi, G.; Haverkorn, M.

    2014-01-01

    We present high-sensitivity and absolutely calibrated images of diffuse radio polarization at a resolution of about 10 arcmin covering the range 10° < l < 34° and |b| < 5° at 2.3 GHz from the S-band Polarization All Sky Survey and at 4.8 GHz from the Sino-German λ6 cm polarization survey of the Galactic plane. Strong depolarization near the Galactic plane is seen at 2.3 GHz, which correlates with strong Hα emission. We ascribe the depolarization to spatial Faraday rotation measure fluctuations of about 65 rad m-2 on scales smaller than 6-9 pc. We argue that most (about 90 per cent) of the polarized emission seen at 4.8 GHz originates from a distance of 3-4 kpc in the Scutum arm and that the random magnetic field dominates the regular field there. A branch extending from the North Polar Spur towards lower latitudes can be identified from the polarization image at 4.8 GHz but only partly from the polarization image at 2.3 GHz, implying that the branch is at a distance larger than 2-3 kpc. We show that comparison of structure functions of complex polarized intensity with those of polarized intensity can indicate whether the observed polarized structures are intrinsic or caused by Faraday screens. The probability distribution function of gradients from the polarization images at 2.3 GHz indicates that the turbulence in the warm ionized medium is transonic.

  2. An effective science tutorial model for at-risk, academically unacceptable students in grades 4 -- 8: A Delphi study

    NASA Astrophysics Data System (ADS)

    Adair, J. Kathleen

    This study explored science-specific strategies and materials that might be effective components in a Response to Intervention (RTI) science tutorial model for at-risk, academically unsuccessful students in grades 4 -- 8. Through an iterative Delphi process of responding to three rounds of questionnaires, a nationwide panel of 63 experts in the field of science education identified and came to consensus on 44 effective strategies and six instructional materials and types of equipment for supplemental instruction in science, resulting in a three tier RTI tutorial model. This model provides an initial guide for science educators in applicable practices for each tier of the RTI framework, and was developed to assist administrators, program managers, and science educators in developing effective, systemic RTI instructional programming for science education in grades 4 -- 8, and may provide an additional planning tool in determining evidence-based practices that may lead to achievement for at-risk, academically unsuccessful students in grades 4 -- 8. Future research on specific intervention strategies within science and their effects on science achievement are needed, as well as a further examination to test the efficacy of the model on rates of science achievement for at-risk, academically unsuccessful students.

  3. Sounds in the Ocean at 1-100 Hz

    NASA Astrophysics Data System (ADS)

    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.

  4. Null polarimetry near shot noise limit at 1 Hz

    NASA Astrophysics Data System (ADS)

    He, Dechao; Xie, Boya; Feng, Sheng

    2016-04-01

    We describe the principle and report on the realization of a null polarimeter with two demonstrated features: (1) the sensitivity of the system is near shot noise limit and (2) quasi-stationary signals at 1 Hz can be measured without signal modulation. The achieved single-pass sensitivity is 7 × 10-9 rad/ √{ Hz } with a pair of Glan-Taylor polarizers, which should be of great interest for experiments such as observation of vacuum magnetic birefringence and search for new particles. The system is brought near its shot noise limit by appropriate polarization control and coherent heterodyne detection of light, resulting in a sensitivity improvement by two orders of magnitude in comparison with the case of no control on light polarization.

  5. 10-Hz kilowatt-class dye laser system

    NASA Astrophysics Data System (ADS)

    Klimek, Daniel E.; Aldag, Henry R.

    1993-06-01

    Textron Defense Systems (Formerly Avco Research Laboratory) has developed a kilowatt class dye laser. The device is a transverse flow, flashlamp pumped laser that operates at greater than 100 Joules per pulse, and at a repetition rate up to 10 Hz. Operating at 10 Hz, an average power of 1.04 kW was obtained at 585 nm using rhodamine 590 in a methanol/water solvent mixture. The output power was increased to 1.4 kW by adding the triplet quencher cyclooctatetraene to the solution. Under these conditions, the measured efficiency (average laser pulse energy/energy stored in flashlamp capacitors) was 1.8%. A limited series of experiments using alternative dyes was also carried out. Comparable energies and average powers were obtained at 610 nm using rhodamine 610, and 660 nm using sulforhodamine 640.

  6. Null polarimetry near shot noise limit at 1 Hz.

    PubMed

    He, Dechao; Xie, Boya; Feng, Sheng

    2016-04-01

    We describe the principle and report on the realization of a null polarimeter with two demonstrated features: (1) the sensitivity of the system is near shot noise limit and (2) quasi-stationary signals at 1 Hz can be measured without signal modulation. The achieved single-pass sensitivity is 7 × 10(-9) rad/Hz with a pair of Glan-Taylor polarizers, which should be of great interest for experiments such as observation of vacuum magnetic birefringence and search for new particles. The system is brought near its shot noise limit by appropriate polarization control and coherent heterodyne detection of light, resulting in a sensitivity improvement by two orders of magnitude in comparison with the case of no control on light polarization. PMID:27131649

  7. 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

  8. alpha-Hexachlorocyclohexane (alpha-HCH)

    Integrated Risk Information System (IRIS)

    alpha - Hexachlorocyclohexane ( alpha - HCH ) ; CASRN 319 - 84 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Ass

  9. Further observations of nonperiodic optical flickering in HZ Herculis

    NASA Technical Reports Server (NTRS)

    Vanden Bout, P. A.; Moffett, T. J.

    1978-01-01

    High-speed photometric observations of the HZ Her/Her X-1 system show that nonperiodic optical flickering is present during both the ON and OFF portions of the 35-day cycle. The optical flickering is broad band and not confined to emission lines. There is a weak correlation between the amplitude of the flickering and orbital phase but efforts to identify the source of the flickering were unsuccessful.

  10. Polyfluorinated. cap alpha. ,. beta. -unsaturated ketons

    SciTech Connect

    Latypov, R.R.; Belogai, V.D.; Pashkevich, K.I.

    1986-07-10

    The ..cap alpha..,..beta..-unsaturated ketones (..cap alpha..,..beta..-UK), particularly those groups containing fluoroalkyl groups, are of interest as highly reactive compounds having two nonequivalent electrophilic centers. In the present investigation, by boiling polyfluorinated aldehydes with methylketones in glacial acetic acid, they have obtained for the first time the polyfluorinated ..beta..-hydroxy-ketones, the dehydration of which has been used to synthesize the corresponding polyfluorinated ..cap alpha..,..beta..-UK, and their structure and reactions with the nucleophiles NH/sub 3/, PhNH/sub 2/, MeOH have been studied. In the PMR spectra of the ..cap alpha..,..beta..-UK (X)-(XVI) two doublets of triplets are observed at 6.9 and 7.9 ppm, caused by the spin-spin coupling of the olefin protons with the CF/sub 2/ group of the substituent. For ..cap alpha..,..beta..-UK, apart from the cis-trans isomerism relative to the C=C bond, a rotational isomerism is possible, caused by rotation around the C-C single bond. The presence in the IR spectra of absorption bands from nonplanar torsion-deformation vibrations of C-H for a double bond (nu = 975-980 cm/sup -1/) and the high value of the spin-spin coupling constant of the olefin protons (J/sub HH/ = 15 Hz) indicate unambiguously the transconfiguration of the olefin protons.

  11. Magnetic resonance imaging at frequencies below 1 kHz.

    PubMed

    Hilschenz, Ingo; Körber, Rainer; Scheer, Hans-Jürgen; Fedele, Tommaso; Albrecht, Hans-Helge; Mario Cassará, Antonino; Hartwig, Stefan; Trahms, Lutz; Haase, Jürgen; Burghoff, Martin

    2013-02-01

    Within the magnetic resonance imaging (MRI) community the trend is going to higher and higher magnetic fields, ranging from 1.5 T to 7 T, corresponding to Larmor frequencies of 63.8-298 MHz. Since for high-field MRI the magnetization increases with the applied magnetic field, the signal-to-noise-ratio increases as well, thus enabling higher image resolutions. On the other hand, MRI is possible also at ultra-low magnetic fields, as was shown by different groups. The goal of our development was to reach a Larmor frequency range of the low-field MRI system corresponding to the frequency range of human brain activities ranging from near zero-frequency (near-DC) to over 1 kHz. Here, first 2D MRI images of phantoms taken at Larmor frequencies of 100 Hz and 731 Hz will be shown and discussed. These frequencies are examples of brain activity triggered by electrostimulation of the median nerve. The method will allow the magnetic fields of the brain currents to influence the magnetic resonance image, and thus lead to a direct functional imaging modality of neuronal currents. PMID:22898690

  12. Alpha-1 Antitrypsin Test

    MedlinePlus

    ... measures the level of the protein AAT in blood. Alpha-1 antitrypsin phenotype testing evaluates the amount and type of AAT being produced and compares it to normal patterns. Alpha-1 antitrypsin genotype testing ( DNA testing) can ...

  13. Alpha-1 antitrypsin test

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/003715.htm Alpha-1 antitrypsin test To use the sharing features on this page, please enable JavaScript. Alpha-1 antitrypsin is a laboratory test to measure the ...

  14. The Alpha Centauri System.

    ERIC Educational Resources Information Center

    Soderblom, David R.

    1987-01-01

    Describes the Alpha Centauri star system, which is the closest star system to the sun. Discusses the difficulties associated with measurements involving Alpha Centauri, along with some of the recent advances in stellar seismology. Raises questions about the possibilities of planets around Alpha Centauri. (TW)

  15. Gamma power is phase-locked to posterior alpha activity.

    PubMed

    Osipova, Daria; Hermes, Dora; Jensen, Ole

    2008-01-01

    Neuronal oscillations in various frequency bands have been reported in numerous studies in both humans and animals. While it is obvious that these oscillations play an important role in cognitive processing, it remains unclear how oscillations in various frequency bands interact. In this study we have investigated phase to power locking in MEG activity of healthy human subjects at rest with their eyes closed. To examine cross-frequency coupling, we have computed coherence between the time course of the power in a given frequency band and the signal itself within every channel. The time-course of the power was calculated using a sliding tapered time window followed by a Fourier transform. Our findings show that high-frequency gamma power (30-70 Hz) is phase-locked to alpha oscillations (8-13 Hz) in the ongoing MEG signals. The topography of the coupling was similar to the topography of the alpha power and was strongest over occipital areas. Interestingly, gamma activity per se was not evident in the power spectra and only became detectable when studied in relation to the alpha phase. Intracranial data from an epileptic subject confirmed these findings albeit there was slowing in both the alpha and gamma band. A tentative explanation for this phenomenon is that the visual system is inhibited during most of the alpha cycle whereas a burst of gamma activity at a specific alpha phase (e.g. at troughs) reflects a window of excitability. PMID:19098986

  16. Megawatt, 1kHz PRF tunable gyrotron experiments

    SciTech Connect

    Cross, A.W.; Phelps, A.D.R.; Ronald, K.; Spark, S.N.; Turnbull, S.M.

    1995-12-31

    Repetitively pulsed and cw gyrotrons have hitherto used thermionic cathodes whereas cold cathode gyrotrons have normally operated as {open_quote} single shot{close_quote} or low pulse repetition frequency (PRF) devices. The novel results presented here demonstrate that a stacked Blumlein pulse generator driven cold cathode gyrotron developing > 1 MW per pulse (f=90 GHz) may be run with a repetition frequency of 1 kHz over timescales of >30 seconds. A short burst PRF of 2 kHz was also observed. The PRF of the system was limited to 2 kHz by the High Voltage (HV) DC power supply. The gyrotron was based on a two-electrode configuration comprising of a field-immersed, field emission cold cathode and a shaped anode cavity. A superconducting magnet was used to produce the homogeneous intra-cavity magnetic field and a stacked Blumlein pulse generator was used to drive the electron beam. This pulse generator was capable of producing an output voltage up to 300 kV with a 20ns rise time, a 100ns flat top, and a 20ns fall time. The output impedance was 200{Omega} and the energy stored in the generator at a charging voltage of 60 kV was 5.4J. No degradation effects on the mm-wave output was evident due to diode recovery time throughout this series of results. A subsequent conclusion is that the recovery time in the cold cathode gyrotron is less than 500{mu}s.

  17. A single shot TDC with 4.8 ps resolution in 40 nm CMOS for high energy physics applications

    NASA Astrophysics Data System (ADS)

    Prinzie, J.; Steyaert, M.; Leroux, P.

    2015-01-01

    A robust TDC with 4.8 ps bin width has been designed for harsh environments and high energy physics applications. The circuit uses resistive interpolation DLL with a novel dual phase detector architecture. This architecture improves startup- and recovery speed from single event strikes without control voltage ripple trade-off and requires no off-line calibrations. A 0.43 LSB DNL has been measured at a power consumption of 4.2 mW with an extended frequency range from 0.8 GHz to 2.4 GHz. The TDC has been processed in 40 nm CMOS technology.

  18. 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.

  19. 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.

  20. 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%.

  1. Residential 60-Hz magnetic fields and temporal variability

    NASA Astrophysics Data System (ADS)

    Banks, Robert Stephen

    1998-06-01

    The basic question addressed by this research is: How well can data from a single measurement visit estimate longer-term ambient residential 60-Hz magnetic field levels? We undertook repeat 60-Hz magnetic field measurements every two months for one year, plus one additional visit for 14 days of measurement. The study sample consisted of 51 single-family homes, 24 in Minneapolis-St. Paul and 27 in Detroit. Homes were selected by random-digit dialing; each was home to a child eligible to serve a control subject in the National Cancer Institute-Children's Cancer Group Electromagnetic Fields and Radon Study. Trained survey interviewers obtained all measurement data, using an expanded measurement protocol from the main study: (1) spot 60-Hz magnetic field measurements at the centers of three rooms and at the front door; (2) 24- hour (or 14 day) 60-Hz magnetic field measurement in the subject child's bedroom; and (3) geomagnetic field at the centers of two rooms and on the child's bed. The data set available for analysis consists of 349 out of 357 (97.8%) possible sets of spot measurements and 1060 out of 1071 (99.0%) possible days of 24-hour and two-week measurements. A Long-Term Estimate, Child's Bedroom, or LTECB, the geometric mean of the 24-hour measurement geometric means, was used as the reference for analysis. The LTECB was analyzed for house-level main effects and for repeated-measures (temporal) main effects. House-level main effects account for only 41% of the variability in the LTECB. The statistically significant main effects are study area, wire code and population density. A clear trend of increasing LTECB with population density is evident. The seasonal effect is small, but statistically significant. There is no evidence for a day-of-week effect, but a statistically significant diurnal effect is present. Correlation coefficients relating the LTECB to any of three primary single-visit measurement and exposure metric surrogates are >.9. However, when

  2. Lateralized modulation of posterior alpha oscillations in children.

    PubMed

    Vollebregt, Madelon A; Zumer, Johanna M; Ter Huurne, Niels; Castricum, Jesminne; Buitelaar, Jan K; Jensen, Ole

    2015-12-01

    The evidence for a functionally inhibitory role of alpha oscillations is growing stronger, mostly derived from studies in healthy adults investigating spatial attention. It remains unexplored if the modulation of alpha band oscillations plays a similar functional role in typically developing children. The aim of this study was to characterize alpha modulations in children in relation to attentional performance. To this end, the posterior alpha activity (8-12Hz) in children between 7 and 10years old was measured using EEG while they performed a visuospatial covert attention task. We found that the alpha activity decreased in the hemisphere contralateral to the attended hemifield, whereas it relatively increased in the other hemisphere. In addition, we found that the degree of lateralized alpha modulation predicted performance on the attention task by negatively predicting the response time on invalid trials. Of note, children who were behaviorally less influenced by spatial cueing also were children with a clear lateralized alpha modulation pattern, with a significantly stronger alpha lateralization in the left hemisphere than children who were influenced more by spatial cueing. In addition, a bias to the right visual field such as that commonly observed in children, was significantly smaller or absent in the children influenced least by spatial cueing. Among all children, the magnitude of this visual field bias was positively related to the ability to modulate alpha activity. In conclusion, we have shown that the pattern of alpha oscillations modulated by attention is already present in 7-10year old typically developing children. Although a similar pattern is observed in adults, the consequences for behavior are different. The fact that alpha modulation is already present at this age opens up the possibility of using hemispheric alpha lateralization as a tool to study the physiological basis of attention deficits in clinical disorders such as ADHD. PMID:26119021

  3. Calibration issues in delta alpha /alpha .

    NASA Astrophysics Data System (ADS)

    Molaro, Paolo; Centurión, Miriam; Levshakov, Sergei

    Laser Comb Wavelength calibration shows that the ThAr one is locally unreliable with possible deviations of up to 100 {m s}-1 within one order range, while delivering an overall 1 {m s}-1 accuracy (Wilken et al 2009). Such deviation corresponds to delta alpha /alpha ≈ 7* 10-6 for a Fe II-Mg II pair. Comparison of line shifts among the 5 Fe II lines, with almost identical sensitivity to fine structure constant changes, offers a clean way to directly test the presence of possible local wavelength calibration errors of whatever origin. We analyzed 5 absorption systems, with zabs ranging from 1.15 to 2.19 towards 3 bright QSOs. The results show that while some lines are aligned within 20 {m s}-1, others reveal large deviations reaching 200 {m s}-1 or higher and corresponding to a delta alpha /alpha > 10-5 level. The origin of these deviations is not clearly identified but could be related to the adaptation of wavelength calibration to CCD manufacturing irregularities. These results suggest that to draw conclusions from delta alpha /alpha analysis based on one or only few lines must be done with extreme care.

  4. 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.

  5. 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.

  6. Individual differences in alpha frequency drive crossmodal illusory perception.

    PubMed

    Cecere, Roberto; Rees, Geraint; Romei, Vincenzo

    2015-01-19

    Perception routinely integrates inputs from different senses. Stimulus temporal proximity critically determines whether or not these inputs are bound together. Despite the temporal window of integration being a widely accepted notion, its neurophysiological substrate remains unclear. Many types of common audio-visual interactions occur within a time window of ∼100 ms. For example, in the sound-induced double-flash illusion, when two beeps are presented within ∼100 ms together with one flash, a second illusory flash is often perceived. Due to their intrinsic rhythmic nature, brain oscillations are one candidate mechanism for gating the temporal window of integration. Interestingly, occipital alpha band oscillations cycle on average every ∼100 ms, with peak frequencies ranging between 8 and 14 Hz (i.e., 120-60 ms cycle). Moreover, presenting a brief tone can phase-reset such oscillations in visual cortex. Based on these observations, we hypothesized that the duration of each alpha cycle might provide the temporal unit to bind audio-visual events. Here, we first recorded EEG while participants performed the sound-induced double-flash illusion task and found positive correlation between individual alpha frequency (IAF) peak and the size of the temporal window of the illusion. Participants then performed the same task while receiving occipital transcranial alternating current stimulation (tACS), to modulate oscillatory activity either at their IAF or at off-peak alpha frequencies (IAF±2 Hz). Compared to IAF tACS, IAF-2 Hz and IAF+2 Hz tACS, respectively, enlarged and shrunk the temporal window of illusion, suggesting that alpha oscillations might represent the temporal unit of visual processing that cyclically gates perception and the neurophysiological substrate promoting audio-visual interactions. PMID:25544613

  7. Neurofeedback training of EEG alpha rhythm enhances episodic and working memory.

    PubMed

    Hsueh, Jen-Jui; Chen, Tzu-Shan; Chen, Jia-Jin; Shaw, Fu-Zen

    2016-07-01

    Neurofeedback training (NFT) of the alpha rhythm has been used for several decades but is still controversial in regards to its trainability and effects on working memory. Alpha rhythm of the frontoparietal region are associated with either the intelligence or memory of healthy subjects and are also related to pathological states. In this study, alpha NFT effects on memory performances were explored. Fifty healthy participants were recruited and randomly assigned into a group receiving a 8-12-Hz amplitude (Alpha) or a group receiving a random 4-Hz amplitude from the range of 7 to 20 Hz (Ctrl). Three NFT sessions per week were conducted for 4 weeks. Working memory was assessed by both a backward digit span task and an operation span task, and episodic memory was assessed using a word pair task. Four questionnaires were used to assess anxiety, depression, insomnia, and cognitive function. The Ctrl group had no change in alpha amplitude and duration. In contrast, the Alpha group showed a progressive significant increase in the alpha amplitude and total alpha duration of the frontoparietal region. Accuracies of both working and episodic memories were significantly improved in a large proportion of participants of the Alpha group, particularly for those with remarkable alpha-amplitude increases. Scores of four questionnaires fell in a normal range before and after NFT. The current study provided supporting evidence for alpha trainability within a small session number compared with that of therapy. The findings suggested the enhancement of working and episodic memory through alpha NFT. Hum Brain Mapp 37:2662-2675, 2016. © 2016 Wiley Periodicals, Inc. PMID:27038114

  8. 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. PMID:22119661

  9. Theoretical investigation of a novel high density cage compound 4,8,11,14,15-pentanitro-2,6,9,13-tetraoxa-4,8,11,14,15-pentaazaheptacyclo[5.5.1.1(3,11).1(5,9)] pentadecane.

    PubMed

    Lin, He; Zhu, Shun-guan; Zhang, Lin; Peng, Xin-hua; Chen, Peng-yuan; Li, Hong-zhen

    2013-03-01

    A novel polynitro cage compound 4,8,11,14,15-pentanitro-2,6,9,13-tetraoxa-4,8,11,14,15-pentaazaheptacyclo [5.5.1.1(3,11).1(5,9)]pentadecane(PNTOPAHP) has been designed and investigated at the DFT-B3LYP/6-31(d) level. Properties, such as electronic structure, IR spectrum, heat of formation, thermodynamic properties and crystal structure have been predicted. This compound is most likely to crystallize in C2/c space group, and the corresponding cell parameters are Z = 8, a = 29.78 Å, b = 6.42 Å, c = 32.69 Å, α = 90.00°, β = 151.05°, γ = 90.00° and ρ = 1.94 g/cm(3). In addition, the detonation velocity and pressure have also been calculated by the empirical Kamlet-Jacobs equation. As a result, the detonation velocity and pressure of this compound are 9.82 km/s, 44.67 GPa, respectively, a little higher than those of 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane(TEX, 9.28 km/s, 40.72 GPa). This compound has a comparable chemical stability to TEX, based on the N-NO(2) trigger bond length analysis. The bond dissociation energy ranges from 153.09 kJ mol(-1) to 186.04 kJ mol(-1), which indicates that this compound meets the thermal stability requirement as an exploitable HEDM. PMID:23111684

  10. 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.

  11. 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).

  12. 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.

  13. 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.

  14. 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. PMID:25760689

  15. [Alpha1-adrenoceptor subtypes and alpha1-adrenoceptor antagonists].

    PubMed

    Muramatsu, Ikunobu; Suzuki, Fumiko; Tanaka, Takashi; Yamamoto, Hatsumi; Morishima, Shigeru

    2006-03-01

    Alpha(1)-adrenoceptors are widely distributed in the human body and play important physiologic roles. Three alpha(1)-adrenoceptor subtypes (alpha(1A), alpha(1B) and alpha(1D)) have been cloned and show different pharmacologic profiles. In addition, a putative alpha(1)-adrenoceptor (alpha(1L) subtype) has also been proposed. Recently, three drugs (tamsulosin, naftopidil, and silodosin) have been developed in Japan for the treatment of urinary obstruction in patients with benign prostatic hyperplasia. In this review, we describe recent alpha(1)-adrenoceptor subclassifications and the pharmacologic characteristics (subtype selectivity and clinical relevance) of alpha(1)-adrenoceptor antagonists. PMID:16518082

  16. Cortical EEG alpha rhythms reflect task-specific somatosensory and motor interactions in humans.

    PubMed

    Babiloni, Claudio; Del Percio, Claudio; Arendt-Nielsen, Lars; Soricelli, Andrea; Romani, Gian Luca; Rossini, Paolo Maria; Capotosto, Paolo

    2014-10-01

    Anticipating sensorimotor events allows adaptive reactions to environment with crucial implications for self-protection and survival. Here we review several studies of our group that aimed to test the hypothesis that the cortical processes preparing the elaboration of sensorimotor interaction is reflected by the reduction of anticipatory electroencephalographic alpha power (about 8-12Hz; event-related desynchronization, ERD), as an index that regulate task-specific sensorimotor processes, accounted by high-alpha sub-band (10-12Hz), rather than a general tonic alertness, accounted by low-alpha sub-band (8-10Hz). In this line, we propose a model for human cortical processes anticipating warned sensorimotor interactions. Overall, we reported a stronger high-alpha ERD before painful than non-painful somatosensory stimuli that is also predictive of the subjective evaluation of pain intensity. Furthermore, we showed that anticipatory high-alpha ERD increased before sensorimotor interactions between non-painful or painful stimuli and motor demands involving opposite hands. In contrast, sensorimotor interactions between painful somatosensory and sensorimotor demands involving the same hand decreased anticipatory high-alpha ERD, due to a sort of sensorimotor "gating" effect. In conclusion, we suggest that anticipatory cortical high-alpha rhythms reflect the central interference and/or integration of ascending (sensory) and descending (motor) signals relative to one or two hands before non-painful and painful sensorimotor interactions. PMID:24929901

  17. 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.

  18. Event counting alpha detector

    DOEpatents

    Bolton, Richard D.; MacArthur, Duncan W.

    1996-01-01

    An electrostatic detector for atmospheric radon or other weak sources of alpha radiation. In one embodiment, nested enclosures are insulated from one another, open at the top, and have a high voltage pin inside and insulated from the inside enclosure. An electric field is produced between the pin and the inside enclosure. Air ions produced by collision with alpha particles inside the decay volume defined by the inside enclosure are attracted to the pin and the inner enclosure. With low alpha concentrations, individual alpha events can be measured to indicate the presence of radon or other alpha radiation. In another embodiment, an electrical field is produced between parallel plates which are insulated from a single decay cavity enclosure.

  19. Alpha-particle diagnostics

    SciTech Connect

    Young, K.M.

    1991-01-01

    This paper will focus on the state of development of diagnostics which are expected to provide the information needed for {alpha}- physics studies in the future. Conventional measurement of detailed temporal and spatial profiles of background plasma properties in DT will be essential for such aspects as determining heating effectiveness, shaping of the plasma profiles and effects of MHD, but will not be addressed here. This paper will address (1) the measurement of the neutron source, and hence {alpha}-particle birth profile, (2) measurement of the escaping {alpha}-particles and (3) measurement of the confined {alpha}-particles over their full energy range. There will also be a brief discussion of (4) the concerns about instabilities being generated by {alpha}-particles and the methods necessary for measuring these effects. 51 refs., 10 figs.

  20. Imaging alpha particle detector

    DOEpatents

    Anderson, D.F.

    1980-10-29

    A method and apparatus for detecting and imaging alpha particles sources is described. A dielectric coated high voltage electrode and a tungsten wire grid constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source to be quantitatively or qualitatively analyzed. A thin polyester film window allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  1. Imaging alpha particle detector

    DOEpatents

    Anderson, David F.

    1985-01-01

    A method and apparatus for detecting and imaging alpha particles sources is described. A conducting coated high voltage electrode (1) and a tungsten wire grid (2) constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source (3) to be quantitatively or qualitatively analyzed. A thin polyester film window (4) allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  2. Event counting alpha detector

    DOEpatents

    Bolton, R.D.; MacArthur, D.W.

    1996-08-27

    An electrostatic detector is disclosed for atmospheric radon or other weak sources of alpha radiation. In one embodiment, nested enclosures are insulated from one another, open at the top, and have a high voltage pin inside and insulated from the inside enclosure. An electric field is produced between the pin and the inside enclosure. Air ions produced by collision with alpha particles inside the decay volume defined by the inside enclosure are attracted to the pin and the inner enclosure. With low alpha concentrations, individual alpha events can be measured to indicate the presence of radon or other alpha radiation. In another embodiment, an electrical field is produced between parallel plates which are insulated from a single decay cavity enclosure. 6 figs.

  3. Deficient attention modulation of lateralized alpha power in schizophrenia.

    PubMed

    Kustermann, Thomas; Rockstroh, Brigitte; Kienle, Johanna; Miller, Gregory A; Popov, Tzvetan

    2016-06-01

    Modulation of 8-14 Hz (alpha) activity in posterior brain regions is associated with covert attention deployment in visuospatial tasks. Alpha power decrease contralateral to to-be-attended stimuli is believed to foster subsequent processing, such as retention of task-relevant input. Degradation of this alpha-regulation mechanism may reflect an early stage of disturbed attention regulation contributing to impaired attention and working memory commonly found in schizophrenia. The present study tested this hypothesis of early disturbed attention regulation by examining alpha power modulation in a lateralized cued delayed response task in 14 schizophrenia patients (SZ) and 25 healthy controls (HC). Participants were instructed to remember the location of a 100-ms saccade-target cue in the left or right visual hemifield in order to perform a delayed saccade to that location after a retention interval. As expected, alpha power decrease during the retention interval was larger in contralateral than ipsilateral posterior regions, and SZ showed less of this lateralization than did HC. In particular, SZ failed to show hemifield-specific alpha modulation in posterior right hemisphere. Results suggest less efficient modulation of alpha oscillations that are considered critical for attention deployment and item encoding and, hence, may affect subsequent spatial working memory performance. PMID:26854181

  4. 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...

  5. 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....

  6. 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....

  7. 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....

  8. 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...

  9. 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...

  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. CELL CULTURE STUDIES WITH THE IMC-HZ-1 NONOCCLUDED VIRUS

    EPA Science Inventory

    Studies were conducted on an adventitious agent (Hz-lv) isolated from the IMC-Hz-1 cell line. It appeared identical to the virus first obtained by Granados et al. from a persistent infection of this cell line. Restriction endonuclease digestion of Hz-lv DNA indicated the agent wa...

  12. 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...

  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, 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....

  15. 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…

  16. CHARACTERIZATION OF THE DNA OF A NONOCCLUDED BACULOVIRUS, HZ-1V

    EPA Science Inventory

    The DNA of the nonoccluded baculovirus (Hz-1V) obtained from the IMC-Hz-1 cell line was characterized by physicochemical and restriction endonuclease techniques. Hz-1V DNA isolated from purified virus had buoyant densities of 1.58 and 1.54 g/ml in CsC1-ethidium bromide density gr...

  17. 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.

  18. Pathogenic anti-DNA autoantibody-inducing T helper cell lines from patients with active lupus nephritis: isolation of CD4-8- T helper cell lines that express the gamma delta T-cell antigen receptor.

    PubMed Central

    Rajagopalan, S; Zordan, T; Tsokos, G C; Datta, S K

    1990-01-01

    The antigen responsible for autoimmunization in systemic lupus erythematosus is unknown. In spite of this obstacle, we show that T helper (Th) cell lines that are functionally relevant to this disease can be established in vitro. We derived a total of 396 interleukin 2-dependent T-cell lines from the in vivo activated T cells of five patients with lupus nephritis. Only 59 (approximately 15%) of these lines had the ability to selectively augment the production of pathogenic anti-DNA autoantibodies that were IgG in class, cationic in charge, specific for native DNA, and clonally restricted in spectrotype. Forty-nine of these autoantibody-inducing Th lines were CD4+ and expressed the alpha beta T-cell receptor (TCR). The other 10 were CD4-8- (double negative), 3 expressing the alpha beta TCR and 7 expressing the gamma delta TCR. All of the autoantibody-inducing Th lines responded to some endogenous antigen presented by autologous B cells. The autoreactive responses of the CD4+ Th lines were restricted to HLA class II antigens, whereas those of the double-negative cells were not. Endogenous heat shock or stress proteins of the HSP60 family that were expressed by the lupus patients' B cells were involved in stimulating an autoreactive proliferation of the gamma delta Th cells. These studies demonstrate a novel helper activity of certain gamma delta T cells in a spontaneous autoimmune response. Images PMID:2144899

  19. A biologically plausible mechanism for neuronal coding organized by the phase of alpha oscillations.

    PubMed

    Gips, Bart; van der Eerden, Jan P J M; Jensen, Ole

    2016-08-01

    The visual system receives a wealth of sensory information of which only little is relevant for behaviour. We present a mechanism in which alpha oscillations serve to prioritize different components of visual information. By way of simulated neuronal networks, we show that inhibitory modulation in the alpha range (~ 10 Hz) can serve to temporally segment the visual information to prevent information overload. Coupled excitatory and inhibitory neurons generate a gamma rhythm in which information is segmented and sorted according to excitability in each alpha cycle. Further details are coded by distributed neuronal firing patterns within each gamma cycle. The network model produces coupling between alpha phase and gamma (40-100 Hz) amplitude in the simulated local field potential similar to that observed experimentally in human and animal recordings. PMID:27320148

  20. Electroacupuncture at 2/100 Hz Activates Antinociceptive Spinal Mechanisms Different from Those Activated by Electroacupuncture at 2 and 100 Hz in Responder Rats

    PubMed Central

    da Silva, Josie Resende Torres; da Silva, Marcelo Lourenço; Prado, Wiliam Alves

    2013-01-01

    We examined the effects of intrathecal injection of desipramine and fluoxetine (selective inhibitors of norepinephrine and 5-HT uptake, resp.), thiorphan and neostigmine (inhibitors of enkephalinase and acetylcholinesterase, resp.), gabapentin (a GABA releaser), and vigabatrin (an inhibitor of GABA-transaminase) on the antinociception induced by 2 Hz, 100 Hz, or 2/100 Hz electroacupuncture (EA) applied bilaterally to the Zusanli (ST36) and Sanyinjiao (SP6) acupoints using the rat tail-flick test. We show that 2 Hz EA antinociception lasts longer after the administration of drugs that increase the spinal availability of norepinephrine, acetylcholine, or GABA; 100 Hz EA antinociception lasts longer after drug that increases the spinal availability of norepinephrine; 2/100 Hz EA antinociception lasts longer after drugs that increase the spinal availability of endogenous opioids or GABA. We conclude that the antinociceptive effect of 2/100 Hz EA is different from the synergistic effect of alternate stimulation at 2 and 100 Hz because the effect of the former is not changed by increasing the spinal availability of serotonin and lasts longer after the administration of vigabatrin. The combination of EA with drugs that increase the availability of spinal neurotransmitters involved in the modulation of nociceptive inputs may result in a synergistic antinociceptive effect in the rat tail-flick test. PMID:24159340

  1. The Dielectric Properties of Martian Soil Simulant JSC Mars-1 in the Range from 20Hz to 10kHz

    NASA Astrophysics Data System (ADS)

    Simões, F.; Trautner, R.; Grard, R.; Hamelin, M.

    2004-03-01

    A laboratory facility has been setup to measure the complex permittivity of soil mixtures as a function of porosity, humidity, and temperature in the range 20 Hz 10 kHz. The influence of porosity and temperature are discussed, and a measurable gravimetric water content threshold is evaluated.

  2. Alpha-Driven MHD and MHD-Induced Alpha Loss in TFTR DT Experiments

    NASA Astrophysics Data System (ADS)

    Chang, Zuoyang

    1996-11-01

    Theoretical calculation and numerical simulation indicate that there can be interesting interactions between alpha particles and MHD activity which can adversely affect the performance of a tokamak reactor (e.g., ITER). These interactions include alpha-driven MHD, like the toroidicity-induced-Alfven-eigenmode (TAE) and MHD induced alpha particle losses or redistribution. Both phenomena have been observed in recent TFTR DT experiments. Weak alpha-driven TAE activity was observed in a NBI-heated DT experiment characterized by high q0 ( >= 2) and low core magnetic shear. The TAE mode appears at ~30-100 ms after the neutral beam turning off approximately as predicted by theory. The mode has an amplitude measured by magnetic coils at the edge tildeB_p ~1 mG, frequency ~150-190 kHz and toroidal mode number ~2-3. It lasts only ~ 30-70 ms and has been seen only in DT discharges with fusion power level about 1.5-2.0 MW. Numerical calculation using NOVA-K code shows that this type of plasma has a big TAE gap. The calculated TAE frequency and mode number are close to the observation. (2) KBM-induced alpha particle loss^1. In some high-β, high fusion power DT experiments, enhanced alpha particle losses were observed to be correlated to the high frequency MHD modes with f ~100-200 kHz (the TAE frequency would be two-times higher) and n ~5-10. These modes are localized around the peak plasma pressure gradient and have ballooning characteristics. Alpha loss increases by 30-100% during the modes. Particle orbit simulations show the added loss results from wave-particle resonance. Linear instability analysis indicates that the plasma is unstable to the kinetic MHD ballooning modes (KBM) driven primarily by strong local pressure gradients. ----------------- ^1Z. Chang, et al, Phys. Rev. Lett. 76 (1996) 1071. In collaberation with R. Nazikian, G.-Y. Fu, S. Batha, R. Budny, L. Chen, D. Darrow, E. Fredrickson, R. Majeski, D. Mansfield, K. McGuire, G. Rewoldt, G. Taylor, R. White, K

  3. Beam spin asymmetries in deeply virtual Compton scattering (DVCS) with CLAS at 4.8 GeV

    NASA Astrophysics Data System (ADS)

    Gavalian, G.; Burkert, V. D.; Elouadrhiri, L.; Holtrop, M.; Stepanyan, S.; Abrahamyan, D.; Adams, G.; Amaryan, M. J.; Ambrozewicz, P.; Anghinolfi, M.; Asavapibhop, B.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Batourine, V.; Battaglieri, M.; Beard, K.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Biselli, A. S.; Bonner, B. E.; Bouchigny, S.; Boiarinov, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Carnahan, B.; Chen, S.; Cole, P. L.; Coleman, A.; Collins, P.; Coltharp, P.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Crede, V.; Cummings, J. P.; Dashyan, N.; de Masi, R.; de Vita, R.; de Sanctis, E.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur, A.; Dharmawardane, K. V.; Dhuga, K. S.; Dickson, R.; Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Fassi, L. El; Empl, A.; Eugenio, P.; Fatemi, R.; Fedotov, G.; Feldman, G.; Feuerbach, R. J.; Forest, T. A.; Funsten, H.; Garçon, M.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Golovatch, E.; Gonenc, A.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hafidi, K.; Hakobyan, H.; Hakobyan, R. S.; Hardie, J.; Hassall, N.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Hu, J.; Huertas, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Joo, K.; Juengst, H. G.; Kalantarians, N.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Kuznetsov, M.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Lima, A. C. S.; Livingston, K.; Lu, H. Y.; Lukashin, K.; MacCormick, M.; Manak, J. J.; Markov, N.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Moriya, K.; Morrow, S. A.; Moteabbed, M.; Mueller, J.; Mutchler, G. S.; Nadel-Turonski, P.; Napolitano, J.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Philips, S. A.; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Popa, I.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Salamanca, J.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Shvedunov, N. V.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Sokhan, D.; Stavinsky, A.; Stepanyan, S. S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Suleiman, R.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Tkabladze, A.; Tkachenko, S.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Yurov, M.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z. W.

    2009-09-01

    We report measurements of the beam spin asymmetry in deeply virtual Compton scattering (DVCS) at an electron beam energy of 4.8 GeV using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The DVCS beam spin asymmetry has been measured in a wide range of kinematics, 1.0

  4. [A trace gas sensor using mid-infrared quantum cascaded laser at 4.8 microm to detect carbon monoxide].

    PubMed

    Chen, Chen; Wang, Biao; Li, Chun-Guang; Li, Jian; Wang, Yi-Ding

    2014-03-01

    Presented in the present paper is a compact instrument developed for rapid, sensitive and continuous monitoring of trace gases in air, with results shown for carbon monoxide concentration. This instrument takes advantage of recent technology in mid-infrared quantum cascaded laser (QCL) operating at 4.8 microm and mercury cadmium telluride (HgCdTe) mid-infrared (MIR) detector, combing MIR multipass herriott cell with 76 m absorption path length to obtain low detection sensitivity down to 50 nmol x mol(-1) level in 4 s acquisition time. Meanwhile, in order to eliminate the instability induced by electrically modulated light source and effectively improve detection limit of the instrument, an optical structure with dual channel path was designed which is based on differential optical absorption spectroscopy method. The experimental results show that the instrument integrated with gas concentration inversion algorithm can be applied to in-situ measurements of trace gases without calibration. Additionally, operator could substitute a QCL operating at a different wavelength to measure other gases. PMID:25208424

  5. Geomechanical analysis of fluid injection and seismic fault slip for the Mw4.8 Timpson, Texas, earthquake sequence

    NASA Astrophysics Data System (ADS)

    Fan, Zhiqiang; Eichhubl, Peter; Gale, Julia F. W.

    2016-04-01

    An earthquake sequence that culminated in a Mw4.8 strike-slip event near Timpson, east Texas, the largest reported earthquake to date in that region, had previously been attributed to wastewater injection starting 17 months before the onset of recorded seismic activity. To test if this earthquake sequence can be attributed to wastewater injection, we conducted coupled poroelastic finite element simulations to assess the spatial and temporal evolution of pore pressure and stress field in the vicinity of the injection wells and to calculate the Coulomb failure stress on the seismogenic fault as a function of the permeability of the injection layer, fault orientation, fault permeability, and orientation and magnitude of the in situ stress. We find that injection-induced fault slip is plausible within the range of selected model input parameters, with slip favored by low reservoir permeability, low fault permeability, and a favorable orientation of the fault relative to the in situ stress state. Other combinations of equally plausible input parameters predict no slip within 96 months of simulated injection. Under most favorable boundary conditions for fault slip, fault slip occurs 7 months after the start of injection. Our results highlight the importance of detailed geomechanical site characterization for robust fault stability assessment prior to wastewater injection.

  6. ``IT'S ALL IN MOTION" -- A Hands-On Astronomy Workshop For Teachers of Grades 4-8

    NASA Astrophysics Data System (ADS)

    West, M. L.; Liu, C.; Conod, K.

    1999-12-01

    We describe the implementation and results of a four day hands-on astronomy workshop for in-service teachers of grades 4-8. This project, funded by a 1998-1999 IDEAS grant through the Space Telescope Science Institute, included 20 teacher participants from northern New Jersey. We used the workshop's unifying theme -- ``It's All in Motion!" -- to present to the teachers fundamental astrophysical concepts, relevant math and computer skills, and astronomy activities for their classrooms. We learned that there is a great need for this type of training, especially in New Jersey where there are new core curriculum standards and a newly mandated test in science for students in 4th and 8th grades. While the teachers learned content at different rates, the hands-on format gave them confidence to try some of these activities in their classes, especially among under-represented minorities. The most effective activities included human sundials, Sunspotters to measure the rotation of the Earth in 2 minutes, craters in the sand, group mini-reports from posters, speed calculations, physics and astronomy songs, the Ophiuchus Sculpture, a planetarium visit (especially needed in our urban area where the light pollution is severe), and Internet guided sites (See http://www.csam.montclair.edu/ west/ideasresources.html).

  7. Electron paramagnetic resonance study of partially oriented clay platelets intercalated with copper(II) 1,4,8,11-tetraazacyclotetradecane.

    PubMed

    So, Hyunsoo; Jung, Hyun; Choy, Jin-Ho; Belford, R Linn

    2005-03-01

    Electron paramagnetic resonance (EPR) spectra of powder and oriented films of montmorillonite, hectorite, and saponite intercalated with [Cu(cyclam)](2+) (cyclam = 1,4,8,11-tetraazacyclotetradecane) exhibit three components: an orientation-dependent component without hyperfine features, an orientation-dependent component with hyperfine features, and an orientation-independent component without hyperfine feature. EPR spectra of [Cu(cyclam)](2+)-saponite, which exhibit only two components and the best resolved hyperfine features, were simulated. The spectra indicate that a large portion of the saponite platelets are inclined to the glass surface, although they tend to align with their basal planes parallel to the glass surface. The orientation-dependent spectra could be simulated by introducing a Gaussian distribution with a standard deviation of 20 degrees for the inclination angle. The standard deviation may be used as a disorder parameter for the microcrystals assembled on glass plates. Spectral simulation also shows that the CuN(4) plane of [Cu(cyclam)](2+) is parallel to the clay layers. EPR spectra of some other partially oriented systems are also discussed. PMID:16851360

  8. Measurements of H(z) and DA(z) from the two-dimensional two-point correlation function of Sloan Digital Sky Survey luminous red galaxies

    NASA Astrophysics Data System (ADS)

    Chuang, Chia-Hsun; Wang, Yun

    2012-10-01

    We present a method for measuring the Hubble parameter, H(z), and angular diameter distance, DA(z), from the two-dimensional two-point correlation function and validate it using LasDamas mock galaxy catalogues. Applying our method to the sample of luminous red galaxies from the Sloan Digital Sky Survey Data Release 7, we measure H(z=0.35)≡H(0.35)=82.1-4.9+4.8 km s-1 Mpc -1 and DA(z=0.35)≡DA(0.35)=1048-58+60 Mpc without assuming a dark energy model or a flat universe. We find that the derived measurements of H(0.35) rs(zd)/c and DA(0.35)/rs(zd) [where rs(zd) is the sound horizon at the drag epoch] are nearly uncorrelated, have tighter constraints and are more robust with respect to possible systematic effects. Our galaxy clustering measurements of {H(0.35) rs(zd)/c,DA(0.35)/rs(zd)}={0.0434±0.0018,6.60±0.26} (with the correlation coefficient r = 0.0604) can be used to combine with cosmic microwave background and any other cosmological data sets to constrain dark energy. Our results represent the first measurements of H(z) and DA(z) (or H(z) rs(zd)/c and DA(0.35)/rs(zd)) from galaxy clustering data. Our work has significant implications for future surveys in establishing the feasibility of measuring both H(z) and DA(z) from galaxy clustering data.

  9. The alpha channeling effect

    SciTech Connect

    Fisch, N. J.

    2015-12-10

    Alpha particles born through fusion reactions in a tokamak reactor tend to slow down on electrons, but that could take up to hundreds of milliseconds. Before that happens, the energy in these alpha particles can destabilize on collisionless timescales toroidal Alfven modes and other waves, in a way deleterious to energy confinement. However, it has been speculated that this energy might be instead be channeled into useful energy, so as to heat fuel ions or to drive current. Such a channeling needs to be catalyzed by waves Waves can produce diffusion in energy of the alpha particles in a way that is strictly coupled to diffusion in space. If these diffusion paths in energy-position space point from high energy in the center to low energy on the periphery, then alpha particles will be cooled while forced to the periphery. The energy from the alpha particles is absorbed by the wave. The amplified wave can then heat ions or drive current. This process or paradigm for extracting alpha particle energy collisionlessly has been called alpha channeling. While the effect is speculative, the upside potential for economical fusion is immense. The paradigm also operates more generally in other contexts of magnetically confined plasma.

  10. Alpha-thalassaemia.

    PubMed

    Harteveld, Cornelis L; Higgs, Douglas R

    2010-01-01

    Alpha-thalassaemia is inherited as an autosomal recessive disorder characterised by a microcytic hypochromic anaemia, and a clinical phenotype varying from almost asymptomatic to a lethal haemolytic anaemia.It is probably the most common monogenic gene disorder in the world and is especially frequent in Mediterranean countries, South-East Asia, Africa, the Middle East and in the Indian subcontinent. During the last few decades the incidence of alpha thalassaemia in North-European countries and Northern America has increased because of demographic changes. Compound heterozygotes and some homozygotes have a moderate to severe form of alpha thalassaemia called HbH disease. Hb Bart's hydrops foetalis is a lethal form in which no alpha-globin is synthesized. Alpha thalassaemia most frequently results from deletion of one or both alpha genes from the chromosome and can be classified according to its genotype/phenotype correlation. The normal complement of four functional alpha-globin genes may be decreased by 1, 2, 3 or all 4 copies of the genes, explaining the clinical variation and increasing severity of the disease. All affected individuals have a variable degree of anaemia (low Hb), reduced mean corpuscular haemoglobin (MCH/pg), reduced mean corpuscular volume (MCV/fl) and a normal/slightly reduced level of HbA2. Molecular analysis is usually required to confirm the haematological observations (especially in silent alpha-thalassaemia and alpha-thalassaemia trait). The predominant features in HbH disease are anaemia with variable amounts of HbH (0.8-40%). The type of mutation influences the clinical severity of HbH disease. The distinguishing features of the haemoglobin Bart's hydrops foetalis syndrome are the presence of Hb Bart's and the total absence of HbF. The mode of transmission of alpha thalassaemia is autosomal recessive. Genetic counselling is offered to couples at risk for HbH disease or haemoglobin Bart's Hydrops Foetalis Syndrome. Carriers of alpha+- or

  11. Dual frequency (20.0-19.9 kHz) VLF data

    NASA Technical Reports Server (NTRS)

    Looney, C. H.

    1968-01-01

    Data are presented from 24 months of operation of radio station WWVL. Daily measurements of the 20.0 kHz and 20.0/19.9 kHz signal phase angles corrected in accordance with the NBS measurements are presented in tabular form. The 20.0/19.9 kHz data is a function of the phase angle of the 100 Hz information inherent in the 20.0/19.9 transmissions. This data can be used to resolve the 50 microsecond ambiguity inherent in 20.0 kHz single frequency transmissions.

  12. 40-Hz steady state response in Alzheimer's disease and mild cognitive impairment.

    PubMed

    van Deursen, J A; Vuurman, E F P M; van Kranen-Mastenbroek, V H J M; Verhey, F R J; Riedel, W J

    2011-01-01

    The 40-Hz steady state response (SSR) reflects early sensory processing and can be measured with electroencephalography (EEG). The current study compared the 40-Hz SSR in groups consisting of mild Alzheimer's disease patients (AD) (n=15), subjects with mild cognitive impairment (MCI) (n=20) and healthy elderly control subjects (n=20). All participants were naïve for psychoactive drugs. Auditory click trains at a frequency of 40-Hz evoked the 40-Hz SSR. To evaluate test-retest reliability (TRR), subjects underwent a similar assessment 1 week after the first. The results showed a high TRR and a significant increase of 40-Hz SSR power in the AD group compared to MCI and controls. Furthermore a moderate correlation between 40-Hz SSR power and cognitive performance as measured by ADAS-cog was shown. The results suggest that 40-Hz SSR might be an interesting candidate marker of disease progression. PMID:19237225

  13. Dynamics of alpha control: preparatory suppression of posterior alpha oscillations by frontal modulators revealed with combined EEG and event-related optical signal.

    PubMed

    Mathewson, Kyle E; Beck, Diane M; Ro, Tony; Maclin, Edward L; Low, Kathy A; Fabiani, Monica; Gratton, Gabriele

    2014-10-01

    We investigated the dynamics of brain processes facilitating conscious experience of external stimuli. Previously, we proposed that alpha (8-12 Hz) oscillations, which fluctuate with both sustained and directed attention, represent a pulsed inhibition of ongoing sensory brain activity. Here we tested the prediction that inhibitory alpha oscillations in visual cortex are modulated by top-down signals from frontoparietal attention networks. We measured modulations in phase-coherent alpha oscillations from superficial frontal, parietal, and occipital cortices using the event-related optical signal (EROS), a measure of neuronal activity affording high spatiotemporal resolution, along with concurrently recorded EEG, while participants performed a visual target detection task. The pretarget alpha oscillations measured with EEG and EROS from posterior areas were larger for subsequently undetected targets, supporting alpha's inhibitory role. Using EROS, we localized brain correlates of these awareness-related alpha oscillations measured at the scalp to the cuneus and precuneus. Crucially, EROS alpha suppression correlated with posterior EEG alpha power across participants. Sorting the EROS data based on EEG alpha power quartiles to investigate alpha modulators revealed that suppression of posterior alpha was preceded by increased activity in regions of the dorsal attention network and decreased activity in regions of the cingulo-opercular network. Cross-correlations revealed the temporal dynamics of activity within these preparatory networks before posterior alpha modulation. The novel combination of EEG and EROS afforded localization of the sources and correlates of alpha oscillations and their temporal relationships, supporting our proposal that top-down control from attention networks modulates both posterior alpha and awareness of visual stimuli. PMID:24702458

  14. Thalamic mechanisms underlying alpha-delta sleep with implications for fibromyalgia

    PubMed Central

    Klerman, Elizabeth B.; Adler, Gail K.; Kopell, Nancy J.

    2015-01-01

    Alpha-delta sleep is the abnormal intrusion of alpha activity (8- to 13-Hz oscillations) into the delta activity (1- to 4-Hz oscillations) that defines slow-wave sleep. Alpha-delta sleep is especially prevalent in fibromyalgia patients, and there is evidence suggesting that the irregularities in the sleep of these patients may cause the muscle and tissue pain that characterizes the disorder. We constructed a biophysically realistic mathematical model of alpha-delta sleep. Imaging studies in fibromyalgia patients suggesting altered levels of activity in the thalamus motivated a thalamic model as the source of alpha activity. Since sodium oxybate helps to alleviate the symptoms of fibromyalgia and reduces the amount of alpha-delta sleep in fibromyalgia patients, we examined how changes in the molecular targets of sodium oxybate affected alpha-delta activity in our circuit. Our model shows how alterations in GABAB currents and two thalamic currents, Ih (a hyperpolarization-activated current) and a potassium leak current, transform a circuit that normally produces delta oscillations into one that produces alpha-delta activity. Our findings suggest that drugs that reduce Ih conductances and/or increase potassium conductances, without necessarily increasing GABAB conductances, might be sufficient to restore delta sleep. Furthermore, they suggest that delta sleep might be restored by drugs that preferentially target these currents in the thalamus; such drugs might have fewer side effects than drugs that act systemically. PMID:26245315

  15. The 17 May 2012 M4.8 earthquake near Timpson, East Texas: An event possibly triggered by fluid injection

    NASA Astrophysics Data System (ADS)

    Frohlich, Cliff; Ellsworth, William; Brown, Wesley A.; Brunt, Michael; Luetgert, Jim; MacDonald, Tim; Walter, Steve

    2014-01-01

    This study summarizes our investigation of the 17 May 2012 MW-RMT4.8 earthquake near Timpson, Texas, the largest earthquake recorded historically in eastern Texas. To identify preshocks and aftershocks of the 17 May event we examined the arrivals recorded at Nacogdoches (NATX) 30 km from the 17 May epicenter, at nearby USArray Transportable Array stations, and at eight temporary stations deployed between 26 May 2012 and mid-2013. At NATX we identified seven preshocks, the earliest occurring in April 2008. Reliably located aftershocks recorded by the temporary stations lie along a 6 km long NW-SE linear trend corresponding to a previously mapped basement fault that extends across the highest-intensity (MMI VII) region of the 17 May main shock. Earthquakes in this sequence are relatively shallow—with focal depths ranging from 1.6 to 4.6 km. Evidence supporting these depths include: hypocentral locations of exceptionally well-recorded aftershocks, S-P intervals at the nearest stations, and comparisons of synthetics and observed seismograms. Within 3 km of the linear trend of aftershock activity there are two Class II injection disposal wells injecting at 1.9 km depth beginning in August 2006 and February 2007, with injection rates averaging 42,750 m3/mo and 15,600 m3/mo, respectively. Several observations support the hypothesis that fluid injection triggered the Timpson sequence: well-located epicenters are situated near a mapped basement fault and near high-volume injection wells, focal depths are at or below the depths of injection, and the earliest preshock (April 2008) occurred after the onset of injection in 2006.

  16. Evaluation of battery converters based on 4. 8-MW fuel cell demonstrator inverter. Final report. [Contains brief glossary

    SciTech Connect

    Not Available

    1980-10-01

    Electrical power conditioning is a critical element in the development of advanced electrochemical energy storage systems. This program evaluates the use of existing self-commutated converter technology (as developed by the Power Systems Division of United Technologies for the 4.8-MW Fuel Cell Demonstrator) with modification for use in battery energy storage systems. The program consists of three parts: evaluation of the cost and performance of a self-commutated converter modified to maintain production commonality between battery and fuel cell power conditioners, demonstration of the principal characteristics required for the battery application in MW-scale hardware, and investigation of the technical requirements of operation isolated from the utility system. A power-conditioning system consisting of a self-commutated converter augmented with a phase-controlled rectifier was selected and a preliminary design, prepared. A principal factor in this selection was production commonality with the fuel cell inverter system. Additional types of augmentation, and the use of a self-commutated converter system without augmentation, were also considered. A survey of advanced battery manufacturers was used to establish the dc interface characteristics. The principal characteristics of self-commutated converter operation required for battery application were demonstrated with the aid of an available 0.5-MW development system. A survey of five REA and municipal utilities and three A and E firms was conducted to determine technical requirements for operation in a mode isolated from the utility. Definitive requirements for this application were not established because of the limited scope of this study. 63 figures, 37 tables.

  17. Short-term variability of comet C/2012 S1 (ISON) at 4.8 AU from the Sun

    NASA Astrophysics Data System (ADS)

    Santos-Sanz, P.; Ortiz, J. L.; Morales, N.; Duffard, R.; Pozuelos, F.; Moreno, F.; Fernández-Valenzuela, E.

    2015-03-01

    Context. We observed comet C/2012 S1 (ISON) during six nights in February 2013 when it was at 4.8 AU from the Sun. At this distance and time the comet was not very active and it was theoretically possible to detect photometric variations likely due to the rotation of the cometary nucleus. Aims: The goal of this work is to obtain differential photometry of the comet inner coma using different aperture radii in order to derive a possible rotational period. Methods: Large field of view images were obtained with a 4 k × 4 k CCD at the f/3 0.77 m telescope of La Hita Observatory in Spain. Aperture photometry was performed in order to get relative magnitude variation versus time. Using calibrated star fields we also obtained ISON's R-magnitudes versus time. We applied a Lomb-Scargle periodogram analysis to get possible periodicities for the observed brightness variations, directly related with the rotation of the cometary nucleus. Results: The comet light curve obtained is very shallow, with a peak-to-peak amplitude of 0.03 ± 0.02 mag. A tentative synodic rotational period (single-peaked) of 14.4 ± 1.2 h for ISON's nucleus is obtained from our analysis, but there are other possibilities. We studied the possible effect of the seeing variations in the obtained periodicities during the same night, and from night to night. These seeing variations had no effect on the derived periodicity. We discuss and interpret all possible solutions for the rotational period of ISON's nucleus. Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/575/A52

  18. Alpha Rhythms in Audition: Cognitive and Clinical Perspectives

    PubMed Central

    Weisz, Nathan; Hartmann, Thomas; Müller, Nadia; Lorenz, Isabel; Obleser, Jonas

    2011-01-01

    Like the visual and the sensorimotor systems, the auditory system exhibits pronounced alpha-like resting oscillatory activity. Due to the relatively small spatial extent of auditory cortical areas, this rhythmic activity is less obvious and frequently masked by non-auditory alpha-generators when recording non-invasively using magnetoencephalography (MEG) or electroencephalography (EEG). Following stimulation with sounds, marked desynchronizations can be observed between 6 and 12 Hz, which can be localized to the auditory cortex. However knowledge about the functional relevance of the auditory alpha rhythm has remained scarce so far. Results from the visual and sensorimotor system have fuelled the hypothesis of alpha activity reflecting a state of functional inhibition. The current article pursues several intentions: (1) Firstly we review and present own evidence (MEG, EEG, sEEG) for the existence of an auditory alpha-like rhythm independent of visual or motor generators, something that is occasionally met with skepticism. (2) In a second part we will discuss tinnitus and how this audiological symptom may relate to reduced background alpha. The clinical part will give an introduction into a method which aims to modulate neurophysiological activity hypothesized to underlie this distressing disorder. Using neurofeedback, one is able to directly target relevant oscillatory activity. Preliminary data point to a high potential of this approach for treating tinnitus. (3) Finally, in a cognitive neuroscientific part we will show that auditory alpha is modulated by anticipation/expectations with and without auditory stimulation. We will also introduce ideas and initial evidence that alpha oscillations are involved in the most complex capability of the auditory system, namely speech perception. The evidence presented in this article corroborates findings from other modalities, indicating that alpha-like activity functionally has an universal inhibitory role across sensory

  19. Alpha Particle Diagnostic

    SciTech Connect

    Fisher, Ray, K.

    2009-05-13

    The study of burning plasmas is the next frontier in fusion energy research, and will be a major objective of the U.S. fusion program through U.S. collaboration with our international partners on the ITER Project. For DT magnetic fusion to be useful for energy production, it is essential that the energetic alpha particles produced by the fusion reactions be confined long enough to deposit a significant fraction of their initial ~3.5 MeV energy in the plasma before they are lost. Development of diagnostics to study the behavior of energetic confined alpha particles is a very important if not essential part of burning plasma research. Despite the clear need for these measurements, development of diagnostics to study confined the fast confined alphas to date has proven extremely difficult, and the available techniques remain for the most part unproven and with significant uncertainties. Research under this grant had the goal of developing diagnostics of fast confined alphas, primarily based on measurements of the neutron and ion tails resulting from alpha particle knock-on collisions with the plasma deuterium and tritium fuel ions. One of the strengths of this approach is the ability to measure the alphas in the hot plasma core where the interesting ignition physics will occur.

  20. IUSSP activities. Committee on Historical Demography. Report: Conference on Asian Population History, Taipei, Taiwan, 4-8 January 1996.

    PubMed

    Osirike, A B

    1996-05-01

    This article presents an overview of the Asian Population History Conference held in Taipei, Taiwan, January 4-8, 1996. 41 papers were presented on seven themes: Asian population growth, epidemiological transition and public health, mortality trends in pretransitional populations, marriage patterns and demographic systems, fertility levels and trends in pretransitional Asian populations, migration and population distribution, and family systems. Papers were presented by Anthony Reid; Chris Wilson; Bruce Fetter; Sumit Guha; Sheila Zurbrigg; Timothy Dyson and Monica Das Gupta; Cameron Campbell; Robert Shepherd; Ann Jannetta; Chai-Bin Park, Eise Yokoyama, and Sadahiko Nozaki; Peter Boomgaard; Jose Antonio Ortega Osona; Osamu Saito; Ts'ui-jung Liu and Shi-yung Liu; Wen Shang Yang; Dallas Fernando; Bruce Caldwell; A. Francis Gealogo; S. Irudaya Rajan; Kiyoshi Hamano; Guo Songyi; Wang Feng and James Lee; Christopher Langford; Terence H. Hull; Paul K.C. Liu; Xizhe Peng and Yangfang Hou; Ken'ichi Tomobe; Nokiro O. Tsuya; Peter Xenos; Daniel Doeppers; Chaonan Chen and Su-fen Liu; Jiang Tao; Akira Hayami and Emiko Ochiai; Arthur P. Wolf and Chuang Ying-chang; Myron L. Cohen; Burton Pasternak; Zhongwei Zhao; Li-shou Yang, Arland Thornton, and Tamara Hareven; Chi-chun Yi and Yu-hsia Lu; Lai Huimin; Ding Yizhuang; and John Caldwell, who chaired the concluding session. John Caldwell concluded that the conference provided an impressive collection of findings on Asian population history. There was much more research possible, particularly research based on India's rich historical data archives. Research was needed to confirm the assertion that Asian mortality transition began after the two world wars. A focus on natural family planning methods used prior to the transition was suggested. International Union for Scientific Study of Population Committee Chairman David Reher suggested multidisciplinary research on Asian differences in fertility, mortality, and migration. Hayami and Ts

  1. Thermodynamic and kinetic properties of a red wine pigment: catechin-(4,8)-malvidin-3-O-glucoside.

    PubMed

    Nave, Frederico; Petrov, Vesselin; Pina, Fernando; Teixeira, Natércia; Mateus, Nuno; de Freitas, Victor

    2010-10-28

    Catechin-(4,8)-malvidin-3-glucoside, a red pigment adduct (at acid pH) found in red wine and resulting from the reaction between malvidin-3-glucoside and flavan-3-ols during wine aging, was synthesized. The thermodynamic and kinetic constants of the network of chemical reactions were fully determined by stopped flow: (i) Direct pH jumps, from thermal equilibrated solutions at pH = 1.0 (flavylium cation, AH(+)), show three kinetic processes. The first one occurs within the mixing time of the stopped flow and leads to the formation of quinoidal bases A and/or A(-) depending on the final pH; the second one takes place with a rate constant equal to 0.075 + 33[H(+)] and was attributed to the hydration reaction that forms the pseudobases (hemiketals), B/B(-). The third process is much slower, 2 × 10(-4) s(-1), and is due to the cis-trans isomerization giving rise to a small fraction of trans-chalcones, Ct/Ct(-). (ii) Reverse pH jumps from the thermally equilibrated solution at moderate to neutral pH values back to a sufficiently acidic medium clearly distinguish three kinetic processes: the first one takes place within the dead time and is due to the protonation of the bases; the second process occurs with the same rate constant of the hydration reaction monitored by direct pH jumps and is attributed to the formation of flavylium cation from the B; the last process occurs with a rate constant of 1.8 s(-1), and results from the formation of AH(+) from Ct through B, reflecting the rate of the ring closure (tautomerization). The separation of the hydration from the tautomerization upon a reverse pH jump is only possible because at pH < 1 the former reaction is faster than the last. An identical situation was observed for malvidin-3-glucoside (oenin) for pH < 2. PMID:20925351

  2. Growth, Thermal and Spectral Properties of Er3+-Doped and Er3+/Yb3+-Codoped Li3Ba2La3(WO4)8 Crystals

    PubMed Central

    Xiao, Bin; Lin, Zhoubin; Zhang, Lizhen; Huang, Yisheng; Wang, Guofu

    2012-01-01

    This paper reports the growth and spectral properties of Er3+-doped and Er3+/Yb3+-codoped Li3Ba2La3(WO4)8 crystals. The Er3+: Li3Ba2La3(WO4)8 crystal with dimensions of 56 mm×28 mm×9 mm and Er3+/Yb3+: Li3Ba2La3(WO4)8 crystal with dimensions of 52 mm×24 mm×8 mm were obtained by the top-seeded solution growth (TSSG) method. Thermal expansion coefficients and thermal conductivity of both crystals were measured. The spectroscopic characterizations of both crystals were investigated. The spectroscopic analysis reveals that the Er3+/Yb3+: Li3Ba2La3(WO4)8 crystal has much better optical properties than the Er3+: Li3Ba2La3(WO4)8 crystal, thus it may become a potential candidate for solid-state laser gain medium material. PMID:22808214

  3. 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. PMID:21568440

  4. Coils performances of superconducting cables for 50/60 Hz applications

    SciTech Connect

    Lacaze, A.; Laumond, Y. ); Tavergnier, J.P.; Fevrier, A.; Verhaege, T. ); Dalle, B.; Ansart, A. )

    1991-03-01

    Multifilamentary superconducting wires with a greatly reduced level of losses have been produced with unit lengths of several tens of kilometers by AISA (GEC ALSTHOM - IGC). With the reduction of the filament diameter, proximity effects are avoided and the authors take a maximum advantage of the reversible motion of flux lines, so that the hysteretic and matrix losses are lower. In this paper the authors report on 50 Hz and DC quench currents, 50 Hz AC losses, 50 Hz electromagnetic stability results.

  5. 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...

  6. Breeding for 50-kHz positive affective vocalization in rats.

    PubMed

    Burgdorf, Jeffrey; Panksepp, Jaak; Brudzynski, Stefan M; Kroes, Roger; Moskal, Joseph R

    2005-01-01

    Adolescent and adult rats exhibit at least two distinct ultrasonic vocalizations that reflect distinct emotional states. Rats exhibit 22-kHz calls during social defeat, drug withdrawal, as well as in anticipation of aversive events. In contrast, 50-kHz calls are exhibited in high rates during play behavior, mating, as well as in anticipation of rewarding events. The neurochemistry of 22-kHz and 50-kHz calls closely matches that of negative and positive emotional systems in humans, respectively. The aim of this study was to replicate and further evaluate selective breeding for 50-kHz vocalization, in preparation for the analysis of the genetic underpinnings of the 50-kHz ultrasonic vocalization (USV). Isolate housed adolescent rats (23-26 days old) received experimenter administered tactile stimulation (dubbed "tickling"), which mimicked the rat rough-and-tumble play behavior. This stimulation has previously been shown to elicit high levels of 50-kHz USVs and to be highly rewarding in isolate-housed animals. Each tickling session consisted of 4 cycles of 15 seconds stimulation followed by 15 seconds no stimulation for a total of 2 min, and was repeated once per day across 4 successive days. Rats were then selected for either High or Low levels of sonographically verified 50-kHz USVs in response to the stimulation, and a randomly selected line served as a control (Random group). Animals emitted both 22-kHz and 50-kHz types of calls. After 5 generations, animals in the High Line exhibited significantly more 50-kHz and fewer 22-kHz USVs than animals in the Low Line. Animals selected for low levels of 50-kHz calls showed marginally more 22-kHz USVs then randomly selected animals but did not differ in the rate of 50-kHz calls. These results extend our previous findings that laboratory rats could be bred for differential rates of sonographically verified 50-kHz USVs. PMID:15674533

  7. Alarm pheromone does not modulate 22-kHz calls in male rats.

    PubMed

    Muyama, Hiromi; Kiyokawa, Yasushi; Inagaki, Hideaki; Takeuchi, Yukari; Mori, Yuji

    2016-03-15

    Rats are known to emit a series of ultrasonic vocalizations, termed 22-kHz calls, when exposed to distressing stimuli. Pharmacological studies have indicated that anxiety mediates 22-kHz calls in distressed rats. We previously found that exposure to the rat alarm pheromone increases anxiety in rats. Therefore, we hypothesized that the alarm pheromone would increase 22-kHz calls in pheromone-exposed rats. Accordingly, we tested whether exposure to the alarm pheromone induced 22-kHz calls, as well as whether the alarm pheromone increased 22-kHz calls in response to an aversive conditioned stimulus (CS). Rats were first fear-conditioned to an auditory and contextual CS. On the following day, the rats were either exposed to the alarm pheromone or a control odor that was released from the neck region of odor-donor rats. Then, the rats were re-exposed to the aversive CS. The alarm pheromone neither induced 22-kHz calls nor increased 22-kHz calls in response to the aversive CS. In contrast, the control odor unexpectedly reduced the total number and duration of 22-kHz calls elicited by the aversive CS, as well as the duration of freezing. These results suggest that the alarm pheromone does not affect 22-kHz calls in rats. However, we may have found evidence for an appeasing olfactory signal, released from the neck region of odor-donor rats. PMID:26796788

  8. Independent Causal Contributions of Alpha- and Beta-Band Oscillations during Movement Selection

    PubMed Central

    Stolk, Arjen; Marshall, Tom R.; Esterer, Sophie; Sharp, Poppy; Dijkerman, H. Chris; de Lange, Floris P.; Toni, Ivan

    2016-01-01

    To select a movement, specific neuronal populations controlling particular features of that movement need to be activated, whereas other populations are downregulated. The selective (dis)inhibition of cortical sensorimotor populations is governed by rhythmic neural activity in the alpha (8–12 Hz) and beta (15–25 Hz) frequency range. However, it is unclear whether and how these rhythms contribute independently to motor behavior. Building on a recent dissociation of the sensorimotor alpha- and beta-band rhythms, we test the hypothesis that the beta-band rhythm governs the disinhibition of task-relevant neuronal populations, whereas the alpha-band rhythm suppresses neurons that may interfere with task performance. Cortical alpha- and beta-band rhythms were manipulated with transcranial alternating current stimulation (tACS) while human participants selected how to grasp an object. Stimulation was applied at either 10 or 20 Hz and was imposed on the sensorimotor cortex contralaterally or ipsilaterally to the grasping hand. In line with task-induced changes in endogenous spectral power, the effect of the tACS intervention depended on the frequency and site of stimulation. Whereas tACS stimulation generally increased movement selection times, 10 Hz stimulation led to relatively faster selection times when applied to the hemisphere ipsilateral to the grasping hand, compared with other stimulation conditions. These effects occurred selectively when multiple movements were considered. These observations functionally differentiate the causal contribution of alpha- and beta-band oscillations to movement selection. The findings suggest that sensorimotor beta-band rhythms disinhibit task-relevant populations, whereas alpha-band rhythms inhibit neuronal populations that could interfere with movement selection. SIGNIFICANCE STATEMENT This study shows dissociable effects of 10 Hz and 20 Hz tACS on the duration of movement selection. These observations have two elements of

  9. ALPHA MIS: Reference manual

    SciTech Connect

    Lovin, J.K.; Haese, R.L.; Heatherly, R.D.; Hughes, S.E.; Ishee, J.S.; Pratt, S.M.; Smith, D.W.

    1992-02-01

    ALPHA is a powerful and versatile management information system (MIS) initiated and sponsored and by the Finance and Business Management Division of Oak Ridge National Laboratory, who maintain and develop it in concert with the Business Systems Division for its Information Center. A general-purpose MIS, ALPHA allows users to access System 1022 and System 1032 databases to obtain and manage information. From a personal computer or a data terminal, Energy Systems employees can use ALPHA to control their own report reprocessing. Using four general commands (Database, Select, Sort, and Report) they can (1) choose a mainframe database, (2) define subsets within it, (3) sequentially order a subset by one or more variables, and (4) generate a report with their own or a canned format.

  10. Synthesis and photoluminescence properties of near-UV pumped yellow-emitting Li3Ba2La3(WO4)8:Dy3+ phosphors

    NASA Astrophysics Data System (ADS)

    Wang, G. Q.; Gong, X. H.; Chen, Y. J.; Huang, J. H.; Lin, Y. F.; Luo, Z. D.; Huang, Y. D.

    2014-05-01

    Li3Ba2La3(WO4)8:Dy3+ yellow-emitting phosphors were synthesized by the solid state reaction method. These phosphors exhibit one intense emission band around 575 nm under excitation at 365 nm. The dependences of the emission intensities and the chromaticity coordinates on Dy3+ concentration were analyzed. The optimum doping concentration of Dy3+ for the phosphor is about 6 mol% and the corresponding chromaticity coordinates is (0.435, 0.476) at room temperature. Besides, the Li3Ba2La3(WO4)8:Dy3+ phosphor shows higher thermal stability than that of (Sr, Ba)2SiO4:Eu2+. The results show that the Li3Ba2La3(WO4)8:Dy3+ phosphor with strong yellow emission may be applied in near ultraviolet pumped white LEDs.

  11. Relative biological effectiveness of alpha-particle emitters in vivo at low doses.

    PubMed

    Howell, R W; Azure, M T; Narra, V R; Rao, D V

    1994-03-01

    The therapeutic potential of radionuclides that emit alpha particles, as well as their associated health hazards, have attracted considerable attention. The 224Ra daughters 212Pb and 212Bi, by virtue of their radiation properties which involve emission of alpha and beta particles in their decay to stable 208Pb, have been proposed as candidates for radioimmunotherapy. Using mouse testes as the experimental model and testicular spermhead survival as the biological end point, the present work examines the radiotoxicity of 212Pb and its daughters. When 212Pb, in equilibrium with its daughters 212Bi, 212Po and 208Tl, was administered directly into the testis, the dose required to achieve 37% survival (D37) was 0.143 +/- 0.014 Gy and the corresponding RBE of the mixed radiation field was 4.7 when compared to the D37 for acute external 120 kVp X rays. This datum, in conjunction with our earlier results for 210Po, was used to obtain an RBE-LET relationship for alpha particles emitted by tissue-incorporated radionuclides: RBE alpha = 4.8 - 6.1 x 10(-2) LET + 1.0 x 10(-3) LET2. Similarly, the dependence of RBE on alpha-particle energy E alpha was given by RBE alpha = 22 E(-0.73) alpha. These relationships, based on in vivo experimental data, may be valuable in predicting biological effects of alpha-particle emitters. PMID:8146279

  12. The Apollo Alpha Spectrometer.

    NASA Technical Reports Server (NTRS)

    Jagoda, N.; Kubierschky, K.; Frank, R.; Carroll, J.

    1973-01-01

    Located in the Science Instrument Module of Apollo 15 and 16, the Alpha Particle Spectrometer was designed to detect and measure the energy of alpha particles emitted by the radon isotopes and their daughter products. The spectrometer sensor consisted of an array of totally depleted silicon surface barrier detectors. Biased amplifier and linear gate techniques were utilized to reduce resolution degradation, thereby permitting the use of a single 512 channel PHA. Sensor identification and in-flight radioactive calibration were incorporated to enhance data reduction.

  13. The Lyman alpha coronagraph

    NASA Technical Reports Server (NTRS)

    Kohl, J. L.; Reeves, E. M.; Kirkham, B.

    1977-01-01

    The rocket-borne Lyman alpha coronagraph (RLAC) is to be used in the absence of a natural solar eclipse to determine coronal temperatures from measurements of the line width of Lyman-alpha and to determine neutral hydrogen densities of coronal material from the absolute intensity. The coronagraph consists of a 75-cm Fastie-Ebert scanning spectrometer with an AMR 641 photoelectric detection system, an off-axis parabolic primary mirror, and an occulting system. A special optical arrangement achieves rejection of radiation from the solar disk.

  14. Experimental performance of a small size two stage depressed collector for a 4.8-9.6 GHz high performance TWT

    NASA Technical Reports Server (NTRS)

    Ramins, P.; Fox, T. A.

    1976-01-01

    Three simple small size two stage depressed collectors were designed and experimentally evaluated in conjunction with a 330 to 520 watt CW, 4.8 to 9.6 GHz traveling wave tube (TWT). Each of the three designs produced a minimum collector efficiency of 80.0 percent considering saturated TWT operation at the maximum of output frequency and at band edges. The highest minimum collector efficiency produced was 80.5 percent with a two stage depressed collector of 4.8 cm diameter by 7 cm high internal dimensions.

  15. 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

  16. Mobile phone emission modulates interhemispheric functional coupling of EEG alpha rhythms.

    PubMed

    Vecchio, Fabrizio; Babiloni, Claudio; Ferreri, Florinda; Curcio, Giuseppe; Fini, Rita; Del Percio, Claudio; Rossini, Paolo Maria

    2007-03-01

    We tested the working hypothesis that electromagnetic fields from mobile phones (EMFs) affect interhemispheric synchronization of cerebral rhythms, an important physiological feature of information transfer into the brain. Ten subjects underwent two electroencephalographic (EEG) recordings, separated by 1 week, following a crossover double-blind paradigm in which they were exposed to a mobile phone signal (global system for mobile communications; GSM). The mobile phone was held on the left side of the subject head by a modified helmet, and orientated in the normal position for use over the ear. The microphone was orientated towards the corner of the mouth, and the antenna was near the head in the parietotemporal area. In addition, we positioned another similar phone (but without battery) on the right side of the helmet, to balance the weight and to prevent the subject localizing the side of GSM stimulation (and consequently lateralizing attention). In one session the exposure was real (GSM) while in the other it was Sham; both sessions lasted 45 min. Functional interhemispheric connectivity was modelled using the analysis of EEG spectral coherence between frontal, central and parietal electrode pairs. Individual EEG rhythms of interest were delta (about 2-4 Hz), theta (about 4-6 Hz), alpha 1 (about 6-8 Hz), alpha 2 (about 8-10 Hz) and alpha 3 (about 10-12 Hz). Results showed that, compared to Sham stimulation, GSM stimulation modulated the interhemispheric frontal and temporal coherence at alpha 2 and alpha 3 bands. The present results suggest that prolonged mobile phone emission affects not only the cortical activity but also the spread of neural synchronization conveyed by interhemispherical functional coupling of EEG rhythms. PMID:17432975

  17. Alpha and gamma band oscillations index differential processing of acoustically reduced and full forms.

    PubMed

    Drijvers, Linda; Mulder, Kimberley; Ernestus, Mirjam

    2016-02-01

    Reduced forms like yeshay for yesterday often occur in conversations. Previous behavioral research reported a processing advantage for full over reduced forms. The present study investigated whether this processing advantage is reflected in a modulation of alpha (8-12Hz) and gamma (30+Hz) band activity. In three electrophysiological experiments, participants listened to full and reduced forms in isolation (Experiment 1), sentence-final position (Experiment 2), or mid-sentence position (Experiment 3). Alpha power was larger in response to reduced forms than to full forms, but only in Experiments 1 and 2. We interpret these increases in alpha power as reflections of higher auditory cognitive load. In all experiments, gamma power only increased in response to full forms, which we interpret as showing that lexical activation spreads more quickly through the semantic network for full than for reduced forms. These results confirm a processing advantage for full forms, especially in non-medial sentence position. PMID:26878718

  18. [alpha]-Oxocarboxylic Acids

    ERIC Educational Resources Information Center

    Kerber, Robert C.; Fernando, Marian S.

    2010-01-01

    Several [alpha]-oxocarboxylic acids play key roles in metabolism in plants and animals. However, there are inconsistencies between the structures as commonly portrayed and the reported acid ionization constants, which result because the acids are predominantly hydrated in aqueous solution; that is, the predominant form is RC(OH)[subscript 2]COOH…

  19. From Alpha to Omega

    ERIC Educational Resources Information Center

    Czaja, Paul Clement

    2006-01-01

    The Alpha point of the authors' life as a Montessori educator began in 1959, when he was a graduate student studying philosophy at Fordham University in the Bronx, New York. While studying the works of the great American philosopher William James, the author came across the writings of Maria Montessori and immediately became captivated by her…

  20. COOMET.AUV.W-S1 supplementary comparison of free-field hydrophone calibrations in the frequency range 250 Hz to 8 kHz

    NASA Astrophysics Data System (ADS)

    Isaev, A. E.; Yi, Chen; Matveev, A. N.; Zihong, Ping

    2015-01-01

    A description is given of COOMET.AUV.W-S1 supplementary comparison of free-field hydrophone calibrations in the frequency range 250 Hz to 8 kHz between Hangzhou Applied Acoustics Research Institute—a pilot and Russian National Research Institute for Physicotechnical and Radio Engineering Measurements. Two standard hydrophones of TC 4033 and GI 55 were calibrated in this comparison. Reciprocity method, comparison methods, and their facilities were used to assess the current state of free-field hydrophone calibration in the frequency range 250 Hz to 8 kHz of China and Russia. The consistency of calibration results between two participants was confirmed, and the maximum deviation observed was 0.59 dB at frequency 400 Hz. 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. In Vitro Host Range of the Hz-1 Non-Occluded Virus in Arthropod Cell Lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 13 insect cell lines spanning 4 Orders and including Lepidoptera, Coleoptera, Diptera and Homoptera were tested for their ability to replicate the non-occluded virus Hz-1. Only the Lepidpteran cell lines were able to support replication of the virus with TN-CL1 and BCIRL-HZ-AM1 producing ...

  2. 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.

  3. 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.

  4. 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.

  5. A Cross-Cultural and Interdisciplinary Multicultural Education Curriculum for Grades 4-8. Cultural Exchange Task Cards [and] Test Booklet.

    ERIC Educational Resources Information Center

    Botzler, Sally; And Others

    These activities for grades 4-8 are designed to promote understanding, appreciation, and respect for the diversity of cultures in the United States. Activities focus on four groups: American Indians, blacks, Asian Americans, and Mexican Americans. Using an interdisciplinary approach, the material is appropriate for fine arts, language arts, home…

  6. The Cultural Exchange, A Cross-Cultural and Interdisciplinary Multicultural Education Curriculum for Grades 4-8. Trace Your Own Roots. Teacher Manual [and] Student Manual.

    ERIC Educational Resources Information Center

    Nethery, Mary; And Others

    A teacher's manual and student booklet for investigating family genealogy is provided for grades 4-8. The teacher's manual lists student objectives, methods for introducing the unit, a parent letter, student tracking chart, materials needed, vocabulary, group activities, a culminating activity, and a list of additional resources. Students will…

  7. 10 Ready-to-Go Book Report Projects: High Interest Projects That Help Every Student Create Meaningful Responses to Favorite Books. Grades 4-8.

    ERIC Educational Resources Information Center

    Elmore, Rebekah; Gravois, Michael

    Intended for teachers of grades 4-8, this book is designed to challenge students to think critically about the books they are reading. Projects in the book incorporate creative writing skills and artistic and oral development. The book is designed so that teachers can choose the projects that best connect with their students' interests and…

  8. The Nation's Report Card: Civics 2010. National Assessment of Educational Progress at Grades 4, 8, and 12. NCES 2011-466

    ERIC Educational Resources Information Center

    National Center for Education Statistics, 2011

    2011-01-01

    This report presents results of the National Assessment of Educational Progress (NAEP) 2010 civics assessment. National results for representative samples of students at grades 4, 8, and 12 are reported as average scale scores and as a percentage of students performing at or above three achievement levels: "Basic," "Proficient," and "Advanced."…

  9. Intra-day up and down of flux density at 4.8 GHz of the quasar S5 1044+71

    NASA Astrophysics Data System (ADS)

    Liu, X.; Lin, M.-Q.; Liu, J.; Cui, L.; Krichbaum, T. P.; Bignall, H.

    2014-04-01

    Following ATEL #5869, we observed the quasar S5 1044+71 at 4.8 GHz in two Intra-day variability (IDV) sessions with the Urumqi 25m radio telescope of Xinjiang Astronomical Observatory (XAO), we find its flux is rising by ~4% on 11-12 Feb. ...

  10. Presidents: Understanding America's Presidents through Research-Related Activities. A Good Apple Activity Book for Grades 4-8. Revised Edition.

    ERIC Educational Resources Information Center

    Aten, Jerry

    This activity book is designed for grades 4-8 but could be modified for other levels. Mini-units begin with a brief biographical sketch of a U.S. president, including highlights of his life and administration. Twelve trivia questions accompany each sketch and require additional reading from other sources. Thought questions are based on an analysis…

  11. Summary of Alpha Particle Transport

    SciTech Connect

    Medley, S.S.; White, R.B.; Zweben, S.J.

    1998-08-19

    This paper summarizes the talks on alpha particle transport which were presented at the 5th International Atomic Energy Agency's Technical Committee Meeting on "Alpha Particles in Fusion Research" held at the Joint European Torus, England in September 1997.

  12. Alpha Condensates in Atomic Nuclei

    SciTech Connect

    Suzuki, Y.; Matsumura, H.

    2005-11-21

    Recent issues on Bose-Einstein condensation (BEC) of {alpha}-particles in nuclei are reviewed. A candidate of condensates is discussed for some states in 12C and 16O by defining the amount of {alpha} condensation.

  13. 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. PMID:25162425

  14. Lateralization in Alpha-Band Oscillations Predicts the Locus and Spatial Distribution of Attention.

    PubMed

    Ikkai, Akiko; Dandekar, Sangita; Curtis, Clayton E

    2016-01-01

    Attending to a task-relevant location changes how neural activity oscillates in the alpha band (8-13Hz) in posterior visual cortical areas. However, a clear understanding of the relationships between top-down attention, changes in alpha oscillations in visual cortex, and attention performance are still poorly understood. Here, we tested the degree to which the posterior alpha power tracked the locus of attention, the distribution of attention, and how well the topography of alpha could predict the locus of attention. We recorded magnetoencephalographic (MEG) data while subjects performed an attention demanding visual discrimination task that dissociated the direction of attention from the direction of a saccade to indicate choice. On some trials, an endogenous cue predicted the target's location, while on others it contained no spatial information. When the target's location was cued, alpha power decreased in sensors over occipital cortex contralateral to the attended visual field. When the cue did not predict the target's location, alpha power again decreased in sensors over occipital cortex, but bilaterally, and increased in sensors over frontal cortex. Thus, the distribution and the topography of alpha reliably indicated the locus of covert attention. Together, these results suggest that alpha synchronization reflects changes in the excitability of populations of neurons whose receptive fields match the locus of attention. This is consistent with the hypothesis that alpha oscillations reflect the neural mechanisms by which top-down control of attention biases information processing and modulate the activity of neurons in visual cortex. PMID:27144717

  15. Acute effect of carbamazepine on corticothalamic 5-9-Hz and thalamocortical spindle (10-16-Hz) oscillations in the rat.

    PubMed

    Zheng, Thomas W; O'Brien, Terence J; Kulikova, Sofya P; Reid, Christopher A; Morris, Margaret J; Pinault, Didier

    2014-03-01

    A major side effect of carbamazepine (CBZ), a drug used to treat neurological and neuropsychiatric disorders, is drowsiness, a state characterized by increased slow-wave oscillations with the emergence of sleep spindles in the electroencephalogram (EEG). We conducted cortical EEG and thalamic cellular recordings in freely moving or lightly anesthetized rats to explore the impact of CBZ within the intact corticothalamic (CT)-thalamocortical (TC) network, more specifically on CT 5-9-Hz and TC spindle (10-16-Hz) oscillations. Two to three successive 5-9-Hz waves were followed by a spindle in the cortical EEG. A single systemic injection of CBZ (20 mg/kg) induced a significant increase in the power of EEG 5-9-Hz oscillations and spindles. Intracellular recordings of glutamatergic TC neurons revealed 5-9-Hz depolarizing wave-hyperpolarizing wave sequences prolonged by robust, rhythmic spindle-frequency hyperpolarizing waves. This hybrid sequence occurred during a slow hyperpolarizing trough, and was at least 10 times more frequent under the CBZ condition than under the control condition. The hyperpolarizing waves reversed at approximately -70 mV, and became depolarizing when recorded with KCl-filled intracellular micropipettes, indicating that they were GABAA receptor-mediated potentials. In neurons of the GABAergic thalamic reticular nucleus, the principal source of TC GABAergic inputs, CBZ augmented both the number and the duration of sequences of rhythmic spindle-frequency bursts of action potentials. This indicates that these GABAergic neurons are responsible for the generation of at least the spindle-frequency hyperpolarizing waves in TC neurons. In conclusion, CBZ potentiates GABAA receptor-mediated TC spindle oscillations. Furthermore, we propose that CT 5-9-Hz waves can trigger TC spindles. PMID:24308357

  16. BIGEL analysis of gene expression in HL60 cells exposed to X rays or 60 Hz magnetic fields

    NASA Technical Reports Server (NTRS)

    Balcer-Kubiczek, E. K.; Zhang, X. F.; Han, L. H.; Harrison, G. H.; Davis, C. C.; Zhou, X. J.; Ioffe, V.; McCready, W. A.; Abraham, J. M.; Meltzer, S. J.

    1998-01-01

    We screened a panel of 1,920 randomly selected cDNAs to discover genes that are differentially expressed in HL60 cells exposed to 60 Hz magnetic fields (2 mT) or X rays (5 Gy) compared to unexposed cells. Identification of these clones was accomplished using our two-gel cDNA library screening method (BIGEL). Eighteen cDNAs differentially expressed in X-irradiated compared to control HL60 cells were recovered from a panel of 1,920 clones. Differential expression in experimental compared to control cells was confirmed independently by Northern blotting of paired total RNA samples hybridized to each of the 18 clone-specific cDNA probes. DNA sequencing revealed that 15 of the 18 cDNA clones produced matches with the database for genes related to cell growth, protein synthesis, energy metabolism, oxidative stress or apoptosis (including MYC, neuroleukin, copper zinc-dependent superoxide dismutase, TC4 RAS-like protein, peptide elongation factor 1alpha, BNIP3, GATA3, NF45, cytochrome c oxidase II and triosephosphate isomerase mRNAs). In contrast, BIGEL analysis of the same 1,920 cDNAs revealed no differences greater than 1.5-fold in expression levels in magnetic-field compared to sham-exposed cells. Magnetic-field-exposed and control samples were analyzed further for the presence of mRNA encoding X-ray-responsive genes by hybridization of the 18 specific cDNA probes to RNA from exposed and control HL60 cells. Our results suggest that differential gene expression is induced in approximately 1% of a random pool of cDNAs by ionizing radiation but not by 60 Hz magnetic fields under the present experimental conditions.

  17. Development and identification of monoclonal antibodies against meso-Tetra (alpha,alpha,alpha,alpha,-O-phenylacetamide benzene) porphyrin.

    PubMed

    Wang, Fengyang; Huang, Xueying; Du, Li; Li, Weiguo; Qi, Chao

    2007-04-01

    The small molecule meso-Tetra (alpha,alpha,alpha,alpha-o-phenylacetamide benzene) porphyrin was synthesized through the condensation of o-nitrobenzaldehyde and pyrrole followed by reduction of the meso-tetra (o-nitrophenyl) porphyrin. The small molecule, without carrier, was used as complete antigen to immunize BALB/ C mice. Spleen cells producing high titer antibody were removed and fused with myeloma cells of SP2/0 origin. Using a conventional immunization protocol, stable murine monoclonal antibodies (MAbs) producing cell lines to meso-Tetra (alpha,alpha,alpha,alpha-o-phenylacetamide benzene) porphyrin 1F2 were obtained. Subclass determination showed that the clones produce IgG2a types of MAbs. The analytical results of HPLC and MALDI/TOFMS suggest that the purity of MAb 1F2 is 100%, and MAb 1F2 has a relative molecular weight of 156678.8 Da. Our results demonstrated that small molecule meso-Tetra (alpha,alpha,alpha,alpha-o-phenylacetamide benzene) porphyrin, as semiantigen without carrier, can elicit the formation of MAbs. PMID:17451352

  18. 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.

  19. Gamma Activity Coupled to Alpha Phase as a Mechanism for Top-Down Controlled Gating

    PubMed Central

    Bonnefond, Mathilde; Jensen, Ole

    2015-01-01

    Coupling between neural oscillations in different frequency bands has been proposed to coordinate neural processing. In particular, gamma power coupled to alpha phase is proposed to reflect gating of information in the visual system but the existence of such a mechanism remains untested. Here, we recorded ongoing brain activity using magnetoencephalography in subjects who performed a modified Sternberg working memory task in which distractors were presented in the retention interval. During the anticipatory pre-distractor period, we show that the phase of alpha oscillations was coupled with the power of high (80-120Hz) gamma band activity, i.e. gamma power consistently was lower at the trough than at the peak of the alpha cycle (9-12Hz). We further show that high alpha power was associated with weaker gamma power at the trough of the alpha cycle. This result is in line with alpha activity in sensory region implementing a mechanism of pulsed inhibition silencing neuronal firing every ~100 ms. PMID:26039691

  20. 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. PMID:26723270

  1. 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

  2. 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

  3. 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. PMID:24993225

  4. Alpha-globin loci in homozygous beta-thalassemia intermedia.

    PubMed

    Triadou, P; Lapoumeroulie, C; Girot, R; Labie, D

    1983-01-01

    Homozygous beta-thalassemia intermediate (TI) differs from thalassemia major (TM) in being less severe clinically. Associated alpha-thalassemia could account for the TI phenotype by reducing the alpha/non-alpha chain imbalance. We have analyzed the alpha loci of 9 TI and 11 TM patients by restriction endonuclease mapping. All the TM and 7 of the TI patients have the normal complement of four alpha-globin genes (alpha alpha/alpha alpha). One TI patient has three alpha-globin genes (alpha alpha/-alpha), and another TI patient has five alpha genes (alpha alpha/alpha alpha alpha). PMID:6305827

  5. Pheromone synthesis. Part 245: Synthesis and chromatographic analysis of the four stereoisomers of 4,8-dimethyldecanal, the male aggregation pheromone of the red flour beetle, Tribolium castaneum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    All four stereoisomers of 4,8-dimethyldecanal (1) were synthesized from the enantiomers of 2-methyl-1-butanol and citronellal. Enantioselective GC analysis enabled separation of (4R,8R)-1 and (4R,8S)-1 from a mixture of (4S,8R)-1 and (4S,8S)-1, when octakis- (2,3-di-O-methoxymethyl-6-O-t-butyldimet...

  6. Implications for the Number Density of Quasars at z > 4.8 Using VIZJ Imaging from the BTC40 Multicolor Survey

    NASA Astrophysics Data System (ADS)

    Bursick, Shelly; Kennefick, J. D.; Smith, M.; Monier, E.; Hall, P.; Osmer, P.; Dalton, G.; Green, R.

    2009-01-01

    We present the results of optical spectroscopy of four faint high redshift quasar candidates taken with the GMOS -S instrument on Gemini South during the spring 08’ and fall 06’ semesters. These candidates were selected as part of the VIZ and J multicolor BTC40 survey for z > 4.8 quasars. We will discuss implications for the number density of quasars at these redshifts.

  7. Optical wireless transmission of 405 nm, 1.45 Gbit/s optical IM/DD-OFDM signals through a 4.8 m underwater channel.

    PubMed

    Nakamura, Kazuhiko; Mizukoshi, Izumi; Hanawa, Masanori

    2015-01-26

    In this paper, we experimentally demonstrate wireless transmission of optical intensity modulation/direct detection-orthogonal frequency division multiplexing (IM/DD-OFDM) signals in an underwater channel using a field programmable gate array based real-time transmitter. The real-time transmission of a 405 nm 1.45 Gbit/s optical OFDM signal through a 4.8 m underwater channel with an error vector magnitude of approximately 10% was successfully achieved. PMID:25835913

  8. 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.

  9. 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.

  10. The auditory transient 40-Hz response is insensitive to changes in stimulus features.

    PubMed

    Tiitinen, H; Sinkkonen, J; May, P; Näätänen, R

    1994-12-30

    Ten subjects were presented with tone pips occasionally interspersed with deviant tone pips of a higher frequency. The transient 40-Hz response was insensitive to change in qualitative stimulus features. In contrast, stimulus changes elicited a later and slower event-related potential, the mismatch negativity (MMN). As a response to changes in stimulus features implies the existence of a memory system, and because changes in qualitative stimulus aspects do not activate the generator mechanisms underlying the 40-Hz response, the 40-Hz response can be dissociated from memory mechanisms. Furthermore, the analysis of phase-locked (synchronous) and non-phase-locked (asynchronous) responses revealed that the 40-Hz response might be caused by the synchronization of already active oscillators. PMID:7703412

  11. Early diet affects the development of 3-6 Hz EEG activity in infants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This longitudinal study investigated whether diet affects brain physiological functions during infancy. Power spectra (3-6 Hz) of electroencephalographic signals (high density recordings) in the bilateral prefrontal, frontal, central, parietal, occipital, anterior temporal, mid-temporal, and posteri...

  12. Narrow-band 5 kHz hiss observed in the vicinity of the plasmapause

    NASA Astrophysics Data System (ADS)

    Ondoh, T.; Nakamura, Y.; Watanabe, S.; Murakami, T.

    1981-01-01

    Latitudinal distributions of narrow-band 5 kHz hisses have been statistically obtained by using VLF electric field data received from the ISIS-1 and -2 at Syowa station, Antarctica and Kashima station, Japan, in order to study an origin of the narrow-band 5 kHz hisses which are often observed on the ground in mid- and low-latitudes. The result shows that the narrow-band 5 kHz hiss occurs most frequently at geomagnetically invariant latitudes from 55 to 63 deg, which are roughly the plasmapause latitudes at various geomagnetic activities, both in the Northern and Southern Hemispheres. The narrow-band 5 kHz hiss seems to be generated by the cyclotron instabilities of several keV to a few ten keV electrons for the most feasible electron density of 10 to 1000 per cu cm in the vicinity of the equatorial plasmapause.

  13. Source parameters of a M4.8 and its accompanying repeating earthquakes off Kamaishi, NE Japan: Implications for the hierarchical structure of asperities and earthquake cycle

    USGS Publications Warehouse

    Uchida, N.; Matsuzawa, T.; Ellsworth, W.L.; Imanishi, K.; Okada, T.; Hasegawa, A.

    2007-01-01

    We determine the source parameters of a M4.9 ?? 0.1 'characteristic earthquake' sequence and its accompanying microearthquakes at ???50 km depth on the subduction plate boundary offshore of Kamaishi, NE Japan. The microearthquakes tend to occur more frequently in the latter half of the recurrence intervals of the M4.9 ?? 0.1 events. Our results show that the microearthquakes are repeating events and they are located not only around but also within the slip area for the 2001 M4.8 event. From the hierarchical structure of slip areas and smaller stress drops for the microearthquakes compared to the M4.8 event, we infer the small repeating earthquakes rupture relatively weak patches in and around the slip area for the M4.8 event and their activity reflects a stress concentration process and/or change in frictional property (healing) at the area. We also infer the patches for the M4.9 ?? 0.1 and other repeating earthquakes undergo aseismic slip during their interseismic period. Copyright 2007 by the American Geophysical Union.

  14. 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…

  15. Dynamic peripheral visual performance relates to alpha activity in soccer players.

    PubMed

    Nan, Wenya; Migotina, Daria; Wan, Feng; Lou, Chin Ian; Rodrigues, João; Semedo, João; Vai, Mang I; Pereira, Jose Gomes; Melicio, Fernando; Da Rosa, Agostinho C

    2014-01-01

    Many studies have demonstrated the relationship between the alpha activity and the central visual ability, in which the visual ability is usually assessed through static stimuli. Besides static circumstance, however in the real environment there are often dynamic changes and the peripheral visual ability in a dynamic environment (i.e., dynamic peripheral visual ability) is important for all people. So far, no work has reported whether there is a relationship between the dynamic peripheral visual ability and the alpha activity. Thus, the objective of this study was to investigate their relationship. Sixty-two soccer players performed a newly designed peripheral vision task in which the visual stimuli were dynamic, while their EEG signals were recorded from Cz, O1, and O2 locations. The relationship between the dynamic peripheral visual performance and the alpha activity was examined by the percentage-bend correlation test. The results indicated no significant correlation between the dynamic peripheral visual performance and the alpha amplitudes in the eyes-open and eyes-closed resting condition. However, it was not the case for the alpha activity during the peripheral vision task: the dynamic peripheral visual performance showed significant positive inter-individual correlations with the amplitudes in the alpha band (8-12 Hz) and the individual alpha band (IAB) during the peripheral vision task. A potential application of this finding is to improve the dynamic peripheral visual performance by up-regulating alpha activity using neuromodulation techniques. PMID:25426058

  16. 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.

  17. Ultrasonic Plastic Welding Using 90 kHz Upper and Lower Vibration Systems

    NASA Astrophysics Data System (ADS)

    Tsujino, Jiromaru; Ishii, Yasuhiro; Shiraki, Toshiyuki; Yamazaki, Hiroyuki

    1994-05-01

    Direct and transmission welding characteristics of an ultrasonic plastic welding system using 90 kHz upper and lower vibration systems are studied. By using high frequency, welding characteristics of plastic specimens may be improved because ultrasonic vibration absorption by plastic material increases as vibration frequency increases. The 90 kHz ultrasonic vibration source designed consists of a radial-to-longitudinal vibration direction converter with four bolt-clamped Langevin-type piezoelectric ceramic (lead-zircon-titanate; PZT) transducers of 15 mm in diameter. The 90 kHz welding equipment consists of two vibration sources positioned at upper and lower parts and a welding frame. In the case of direct welding of various sheet specimens, the required total velocity of 90 kHz upper and lower welding tips is less than 60% that of 27 kHz welding tips. Direct and transmission welding characteristics of a 90 kHz welding system with two vibration sources are significantly improved compared with those of conventional systems.

  18. Total and local impedances of the chest wall up to 10 Hz.

    PubMed

    Barnas, G M; Yoshino, K; Fredberg, J; Kikuchi, Y; Loring, S H; Mead, J

    1990-04-01

    To understand how bical mechanical chest wall (CW) properties are related to those of the CW as a whole, we measured esophageal and gastric pressures, CW volume changes (measured with a head-out body plethysmograph), and anteroposterior and transverse CW diameter changes (measured with magnetometers attached to the surface) during sinusoidal forcing at the mouth (2.5% vital capacity, 0.5-10 Hz) in four healthy subjects. Total CW resistance decreased sharply as frequency rose to 3-4 Hz and remained relatively constant at higher frequencies. Total CW reactance became less negative with increasing frequency but showed no tendency to change sign. Above 2 Hz, diameters measured at different locations changed asynchronously between and within the rib cage and abdomen. "Local pathway impedances" (ratios of esophageal or gastric pressure to a rate of diameter change) showed frequency dependence similar to that of the total CW less than 3 Hz. Local pathway impedances increased during contraction of respiratory muscles acting on the pathway. We conclude that 1) total CW behavior is mainly a reflection of its individual local properties at less than or equal to 3 Hz, 2) local impedances within the rib cage or within the abdomen can change independently in some situations, and 3) asynchronies that develop within the CW during forcing greater than 3 Hz suggest that two compartments may be insufficient to describe CW properties from impedance measurements. PMID:2140827

  19. Alpha-mannosidosis

    PubMed Central

    Malm, Dag; Nilssen, Øivind

    2008-01-01

    Alpha-mannosidosis is an inherited lysosomal storage disorder characterized by immune deficiency, facial and skeletal abnormalities, hearing impairment, and intellectual disability. It occurs in approximately 1 of 500,000 live births. The children are often born apparently normal, and their condition worsens progressively. Some children are born with ankle equinus or develop hydrocephalus in the first year of life. Main features are immune deficiency (manifested by recurrent infections, especially in the first decade of life), skeletal abnormalities (mild-to-moderate dysostosis multiplex, scoliosis and deformation of the sternum), hearing impairment (moderate-to-severe sensorineural hearing loss), gradual impairment of mental functions and speech, and often, periods of psychosis. Associated motor function disturbances include muscular weakness, joint abnormalities and ataxia. The facial trait include large head with prominent forehead, rounded eyebrows, flattened nasal bridge, macroglossia, widely spaced teeth, and prognathism. Slight strabismus is common. The clinical variability is significant, representing a continuum in severity. The disorder is caused by lysosomal alpha-mannosidase deficiency. Alpha-mannosidosis is inherited in an autosomal recessive fashion and is caused by mutations in the MAN2B1 gene located on chromosome 19 (19 p13.2-q12). Diagnosis is made by measuring acid alpha-mannosidase activity in leukocytes or other nucleated cells and can be confirmed by genetic testing. Elevated urinary secretion of mannose-rich oligosaccharides is suggestive, but not diagnostic. Differential diagnoses are mainly the other lysosomal storage diseases like the mucopolysaccharidoses. Genetic counseling should be given to explain the nature of the disease and to detect carriers. Antenatal diagnosis is possible, based on both biochemical and genetic methods. The management should be pro-active, preventing complications and treating manifestations. Infections must be

  20. Radiofrequency signal affects alpha band in resting electroencephalogram.

    PubMed

    Ghosn, Rania; Yahia-Cherif, Lydia; Hugueville, Laurent; Ducorps, Antoine; Lemaréchal, Jean-Didier; Thuróczy, György; de Seze, René; Selmaoui, Brahim

    2015-04-01

    The aim of the present work was to investigate the effects of the radiofrequency (RF) electromagnetic fields (EMFs) on human resting EEG with a control of some parameters that are known to affect alpha band, such as electrode impedance, salivary cortisol, and caffeine. Eyes-open and eyes-closed resting EEG data were recorded in 26 healthy young subjects under two conditions: sham exposure and real exposure in double-blind, counterbalanced, crossover design. Spectral power of EEG rhythms was calculated for the alpha band (8-12 Hz). Saliva samples were collected before and after the study. Salivary cortisol and caffeine were assessed by ELISA and HPLC, respectively. The electrode impedance was recorded at the beginning of each run. Compared with the sham session, the exposure session showed a statistically significant (P < 0.0001) decrease of the alpha band spectral power during closed-eyes condition. This effect persisted in the postexposure session (P < 0.0001). No significant changes were detected in electrode impedance, salivary cortisol, and caffeine in the sham session compared with the exposure one. These results suggest that GSM-EMFs of a mobile phone affect the alpha band within spectral power of resting human EEG. PMID:25695646

  1. Radiofrequency signal affects alpha band in resting electroencephalogram

    PubMed Central

    Ghosn, Rania; Yahia-Cherif, Lydia; Hugueville, Laurent; Ducorps, Antoine; Lemaréchal, Jean-Didier; Thuróczy, György; de Seze, René

    2015-01-01

    The aim of the present work was to investigate the effects of the radiofrequency (RF) electromagnetic fields (EMFs) on human resting EEG with a control of some parameters that are known to affect alpha band, such as electrode impedance, salivary cortisol, and caffeine. Eyes-open and eyes-closed resting EEG data were recorded in 26 healthy young subjects under two conditions: sham exposure and real exposure in double-blind, counterbalanced, crossover design. Spectral power of EEG rhythms was calculated for the alpha band (8–12 Hz). Saliva samples were collected before and after the study. Salivary cortisol and caffeine were assessed by ELISA and HPLC, respectively. The electrode impedance was recorded at the beginning of each run. Compared with the sham session, the exposure session showed a statistically significant (P < 0.0001) decrease of the alpha band spectral power during closed-eyes condition. This effect persisted in the postexposure session (P < 0.0001). No significant changes were detected in electrode impedance, salivary cortisol, and caffeine in the sham session compared with the exposure one. These results suggest that GSM-EMFs of a mobile phone affect the alpha band within spectral power of resting human EEG. PMID:25695646

  2. Background canceling surface alpha detector

    DOEpatents

    MacArthur, Duncan W.; Allander, Krag S.; Bounds, John A.

    1996-01-01

    A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone.

  3. Background canceling surface alpha detector

    DOEpatents

    MacArthur, D.W.; Allander, K.S.; Bounds, J.A.

    1996-06-11

    A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs.

  4. Proteinaceous alpha-amylase inhibitors.

    PubMed

    Svensson, Birte; Fukuda, Kenji; Nielsen, Peter K; Bønsager, Birgit C

    2004-02-12

    Proteins that inhibit alpha-amylases have been isolated from plants and microorganisms. These inhibitors can have natural roles in the control of endogenous alpha-amylase activity or in defence against pathogens and pests; certain inhibitors are reported to be antinutritional factors. The alpha-amylase inhibitors belong to seven different protein structural families, most of which also contain evolutionary related proteins without inhibitory activity. Two families include bifunctional inhibitors acting both on alpha-amylases and proteases. High-resolution structures are available of target alpha-amylases in complex with inhibitors from five families. These structures indicate major diversity but also some similarity in the structural basis of alpha-amylase inhibition. Mutational analysis of the mechanism of inhibition was performed in a few cases and various protein engineering and biotechnological approaches have been outlined for exploitation of the inhibitory function. PMID:14871655

  5. Long range alpha particle detector

    DOEpatents

    MacArthur, Duncan W.; Wolf, Michael A.; McAtee, James L.; Unruh, Wesley P.; Cucchiara, Alfred L.; Huchton, Roger L.

    1993-01-01

    An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

  6. Long range alpha particle detector

    DOEpatents

    MacArthur, D.W.; Wolf, M.A.; McAtee, J.L.; Unruh, W.P.; Cucchiara, A.L.; Huchton, R.L.

    1993-02-02

    An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

  7. Modeling Solar Lyman Alpha Irradiance

    NASA Technical Reports Server (NTRS)

    Pap, J.; Hudson, H. S.; Rottman, G. J.; Willson, R. C.; Donnelly, R. F.; London, J.

    1990-01-01

    Solar Lyman alpha irradiance is estimated from various solar indices using linear regression analyses. Models developed with multiple linear regression analysis, including daily values and 81-day running means of solar indices, predict reasonably well both the short- and long-term variations observed in Lyman alpha. It is shown that the full disk equivalent width of the He line at 1083 nm offers the best proxy for Lyman alpha, and that the total irradiance corrected for sunspot effect also has a high correlation with Lyman alpha.

  8. ISS Update: Alpha Magnetic Spectrometer

    NASA Video Gallery

    NASA Public Affairs Officer Kelly Humphries interviews Trent Martin, Johnson Space Center project manager for the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. Questions...

  9. EFFECTS OF ELF (EXTREMELY LOW FREQUENCY) (1-120 HZ) AND MODULATED (50 HZ) RF (RADIO FREQUENCY) FIELDS ON THE EFFLUX OF CALCIUM IONS FROM BRAIN TISSUE IN VITRO

    EPA Science Inventory

    The authors have previously shown that 16-Hz, sinusoidal electromagnetic fields can cause enhanced efflux of calcium ions from chick brain tissue, in vitro, in two intensity regions centered on 6 and 40 Vp-p/m. Alternatively, 1-Hz and 30-Hz fields at 40Vp-p/m did not cause enhanc...

  10. 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. PMID:25497686

  11. Emergence of a 600-Hz buzz UP state Purkinje cell firing in alert mice.

    PubMed

    Cheron, G; Prigogine, C; Cheron, J; Márquez-Ruiz, J; Traub, R D; Dan, B

    2014-03-28

    Purkinje cell (PC) firing represents the sole output from the cerebellar cortex onto the deep cerebellar and vestibular nuclei. Here, we explored the different modes of PC firing in alert mice by extracellular recording. We confirm the existence of a tonic and/or bursting and quiescent modes corresponding to UP and DOWN state, respectively. We demonstrate the existence of a novel 600-Hz buzz UP state of firing characterized by simple spikes (SS) of very small amplitude. Climbing fiber (CF) input is able to switch the 600-Hz buzz to the DOWN state, as for the classical UP-to-DOWN state transition. Conversely, the CF input can initiate a typical SS pattern terminating into 600-Hz buzz. The 600-Hz buzz was transiently suppressed by whisker pad stimulation demonstrating that it remained responsive to peripheral input. It must not be mistaken for a DOWN state or the sign of PC inhibition. Complex spike (CS) frequency was increased during the 600-Hz buzz, indicating that this PC output actively contributes to the cerebello-olivary loop by triggering a disinhibition of the inferior olive. During the 600-Hz buzz, the first depolarizing component of the CS was reduced and the second depolarizing component was suppressed. Consistent with our experimental observations, using a 559-compartment single-PC model - in which PC UP state (of about -43mV) was obtained by the combined action of large tonic AMPA conductances and counterbalancing GABAergic inhibition - removal of this inhibition produced the 600-Hz buzz; the simulated buzz frequency decreased following an artificial CS. PMID:24440752

  12. Expression and modulation of IL-1 alpha in murine keratinocytes

    SciTech Connect

    Ansel, J.C.; Luger, T.A.; Lowry, D.; Perry, P.; Roop, D.R.; Mountz, J.D.

    1988-04-01

    Murine and human keratinocytes produce an IL-1-like factor that appears to be similar if not identical to monocyte-derived IL-1. IL-1 may be an important mediator in cutaneous inflammatory responses, however, little is currently known concerning factors that may modulate IL-1 expression in keratinocytes. To address this issue we examined the effect of LPS, UV, and the cell differentiation state on murine keratinocyte IL-1 mRNA expression. Our results indicated that as with the murine P388D1 monocyte cell line, PAM 212 keratinocytes constitutively express abundant amounts of IL-1 alpha mRNA. On exposure to LPS (100 micrograms/ml) for 8 h there was more than 10 times the increase in PAM 212 IL-1 alpha mRNA which was accompanied by a sixfold increase in supernatant IL-1 activity. Similarly UV irradiation had a significant effect on keratinocyte IL-1 alpha expression. High dose UV (300 mJ/cm2) inhibited PAM 212 IL-1 alpha expression at 4, 8, 24, 48 h post-UV whereas a lower dose of UV (100 mJ/cm2) inhibited UV at 4 and 8 h post-UV, but induced IL-1 expression at 24 and 48 h post-UV. The expression of IL-1 alpha varied with the differentiation state of the keratinocytes. Freshly removed newborn murine keratinocytes were found to constitutively express IL-1 alpha mRNA. Keratinocytes grown in low (Ca2+) tissue culture media (0.05 mM) for 6 days, functionally and phenotypically become undifferentiated and express increased quantities of IL-1 alpha mRNA, whereas cells grown in high (Ca2+) media (1.2 mM) for 6 days become terminally differentiated and IL-1 expression ceased. Keratinocytes cultured for 3 days in low (Ca2+) conditions expressed an intermediate level of IL-1 alpha. In contrast, little or no IL-1 beta mRNA was detected in either the PAM 212 cells or newborn murine keratinocytes.

  13. Alpha Kappa Alpha Sorority's Reading Improvement Program for Minorities.

    ERIC Educational Resources Information Center

    Marable, June Morehead

    This document discusses the founding and establishment of Alpha Kappa Alpha Sorority's reading experience pilot project. The efforts of this project were aligned with those of Right to Read and Reading Is Fundamental (RIF). Because of the response from parents and children, plans are being made to increase present operations within the next…

  14. The Mw4.8 Norris Geyser Basin Earthquake of 30 March, 2014 and its Relationship to Crustal Deformation and Seismic Activity of the Yellowstone Volcanic System

    NASA Astrophysics Data System (ADS)

    Farrell, J.; Shelly, D. R.; Smith, R. B.; Puskas, C. M.; Chang, W. L.

    2014-12-01

    The largest earthquake to be recorded in Yellowstone in over 30 years, a magnitude 4.8 earthquake, occurred on March 30, 2014 near the Norris Geyser Basin on the NW side of the 0.64 Ma Yellowstone caldera. The earthquake was felt throughout Yellowstone and the surrounding region. We analyze this unusual event using data from the Yellowstone Seismic and Geodetic networks in the context of active volcanic-tectonic processes of the Yellowstone volcanic system and its relationship to regional swarm seismicity and crustal deformation. Moment tensor analysis of the March 30 earthquake revealed a strike-slip, double-couple source mechanism with no isotropic contribution. This earthquake was part of a larger sequence of earthquake swarm activity in the Norris Geyser Basin area that began in September 2013 and continued into June 2014. During that period, 50-60% of the total seismicity recorded in Yellowstone, including nearly all of the swarm seismicity (earthquakes clustered in time and space), occurred in the Norris Geyser Basin area. In addition, GPS derived deformation data revealed unusually high uplift rates at ~15 cm/yr in the Norris area prior to the MW4.8 event, while a dramatic reversal to subsidence at rates of ~20 cm/yr occurred after the event. Regionally, the much larger Yellowstone caldera had experienced subsidence since January 2010 at rates of ~1.5 cm/yr prior to the MW4.8 event. After March 30, 2014 the caldera reversed to regional uplift at rates of ~10 cm/yr, similar to accelerated uplift rates observed in mid-2004.

  15. Fragment charge and energy distributions in the 1.8-4.8 GeV {sup 3}He + {sup nat}Ag, {sup 197}Au reactions

    SciTech Connect

    Bracken, D.S.; Foxford, E.R.; Kwiatkowski, K.

    1995-10-01

    Moving source fits have been performed for IMFs as a function of observables related to collision violence in the 1.8-4.8 GeV {sup 3}He +{sup nat}Ag, {sup l97}Au reactions. The systematic behavior of the source properties and fragment charge distributions will be reviewed. The evolution of the spectral Coulomb parameters provides evidence for nuclear expansion prior to multifragmentation, suggesting a breakup density of p/p{sub o} {approximately} 1/3. The charge distributions will be examined in terms of power-law fits and moment analyses.

  16. Room Temperature ppb Level Chlorine Gas Sensor Based on Copper (II) 1, 4, 8, 11, 15, 18, 22, 25-octabutoxy-29 H, 31 H-phthalocyanine Films

    SciTech Connect

    Bedi, R. K.; Saini, Rajan; Mahajan, Aman

    2010-12-01

    Spin coating technique has been used to fabricate room temperature chlorine gas sensor based on copper (II) 1, 4, 8, 11, 15, 18, 22, 25-octabutoxy-29 H, 31 H-phthalocyanine (CuPc(OBu){sub 8}) films. Gas sensor shows a response of 185% to few parts per billion level of Cl{sub 2} gas with response time of 9.5 minutes at room temperature. The interactions between sensor and analytes followed first order kinetics with rate constant 0.01{<=}k{<=}0.02. The chemiresistive sensor showed very good stability at room temperature over a long period of time.

  17. Bare-Minimum Fluorous Mixture Synthesis of a Stereoisomer Library of 4,8,12-Trimethylnonadecanols and Predictions of NMR Spectra of Saturated Oligoisoprenoid Stereoisomers

    PubMed Central

    Yeh, Edmund A.-H.; Kumli, Eveline; Damodaran, Krishnan; Curran, Dennis P.

    2013-01-01

    All four diastereomers of a typical saturated oligoisoprenoid, 4,8,12-trimethylnonadecanol, are made by an iterative three step cycle with the aid of traceless thionocarbonate fluorous tags to encode configurations. The tags have a minimum number of total fluorine atoms, starting at zero and increasing in increments of one. With suitable acquisition and data processing, each diastereomer exhibited characteristic chemical shifts of methyl resonances in its 1H and 13C NMR spectra. Together, these shifts provide a basis to predict the appearance of the methyl region of the spectrum of every stereoisomer of higher saturated oligoisoprenoids. PMID:23297872

  18. Room Temperature ppb Level Chlorine Gas Sensor Based on Copper (II) 1, 4, 8, 11, 15, 18, 22, 25-octabutoxy-29 H, 31 H-phthalocyanine Films

    NASA Astrophysics Data System (ADS)

    Bedi, R. K.; Saini, Rajan; Mahajan, Aman

    2010-12-01

    Spin coating technique has been used to fabricate room temperature chlorine gas sensor based on copper (II) 1, 4, 8, 11, 15, 18, 22, 25-octabutoxy-29 H, 31 H-phthalocyanine (CuPc(OBu)8) films. Gas sensor shows a response of 185% to few parts per billion level of Cl2 gas with response time of 9.5 minutes at room temperature. The interactions between sensor and analytes followed first order kinetics with rate constant 0.01≤k≤0.02. The chemiresistive sensor showed very good stability at room temperature over a long period of time.

  19. Synthesis and characterization of Ni(II) complex with 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-dienium bromide

    SciTech Connect

    Yusoff, Latifah M.; Yusoff, Siti Fairus M.; Ismail, Wafiuddin; Yamin, Bohari M.

    2014-09-03

    Nickel(II) complex have been synthesized by treating a 14-membered ring tetraaza macrocyclic compound, 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-dienium, bromide (Me{sub 6}N{sub 4}H{sub 4})Br{sub 2} with nickel acetate in metanol. The complex was characterized using elemental analysis, Fourier Transform Infrared (FTIR), Ultraviolet-Visible (UV-Vis), and single crystal diffraction (X-ray). The nickel atom coordinates through four nitrogen atoms in the ligand. Square planar geometry has been proposed for this complex.

  20. 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

  1. 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

  2. 40Hz-Transcranial alternating current stimulation (tACS) selectively modulates speech perception.

    PubMed

    Rufener, Katharina S; Zaehle, Tino; Oechslin, Mathias S; Meyer, Martin

    2016-03-01

    The present study investigated the functional relevance of gamma oscillations for the processing of rapidly changing acoustic features in speech signals. For this purpose we analyzed repetition-induced perceptual learning effects in 18 healthy adult participants. The participants received either 6Hz or 40Hz tACS over the bilateral auditory cortex, while repeatedly performing a phoneme categorization task. In result, we found that 40Hz tACS led to a specific alteration in repetition-induced perceptual learning. While participants in the non-stimulated control group as well as those in the experimental group receiving 6Hz tACS considerably improved their perceptual performance, the application of 40Hz tACS selectively attenuated the repetition-induced improvement in phoneme categorization abilities. Our data provide causal evidence for a functional relevance of gamma oscillations during the perceptual learning of acoustic speech features. Moreover, we demonstrate that even less than twenty minutes of alternating current stimulation below the individual perceptual threshold is sufficient to affect speech perception. This finding is relevant in that this novel approach might have implications with respect to impaired speech processing in dyslexics and older adults. PMID:26779822

  3. Arc extinction characteristics in power supply frequencies from 50 Hz to 1 MHz

    NASA Astrophysics Data System (ADS)

    Miki, N.; Sawa, K.

    2010-04-01

    It is well-known that arcing phenomena at the break of contacts affect seriously the reliability and lifetime of contacts. Therefore, many papers have reported arc duration, arc extinction current and other characteristics. Recently, in mobile communication application an electro-mechanical switch is said to be superior to a semiconductor switch in insertion loss and isolation, and a RF (radio frequency) MEMS relay has been intensively developed. Based on the above background it is one of important research topics how the frequency of interrupted current affects the characteristics of breaking arc. However, there are few papers on that topic. In this paper the effect of frequency on arc characteristics is investigated in range of the frequency of interrupted current from 50 Hz to 1 MHz. Consequently the followings can be made clear. At the interruption of peak current 2 A arc extinguishes in terms of arc characteristics and circuit conditions up to the frequency of 200 Hz. Above 200 Hz the arc extinguishes at current zero. The current zero extinction takes place up to 500 kHz. Therefore, arc duration decreases with high frequencies and the contact damage caused by arc is reduced with frequency. However, at frequencies higher than 600 kHz an arc is re-ignited after the current zero and failed to extinguish.

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. Operation and thermal modeling of the ISIS H- source from 50 to 2 Hz repetition rates

    NASA Astrophysics Data System (ADS)

    Pereira, H.; Faircloth, D.; Lettry, J.

    2013-02-01

    CERN's Linac4 accelerator H- ion source, currently under construction, will operate at a 2 Hz repetition rate, with pulse length of 0.5 ms and a beam current of 80 mA. Its reliability must exceed 99 % with a mandatory 3 month uninterrupted operation period. A Penning ion source is successfully operated at ISIS; at 50 Hz repetition rate it reliably provides 55 mA H- pulses of 0.25 ms duration over 1 month. The discharge plasma ignition is very sensitive to the temperatures of the discharge region, especially of its cathode. The investigation by modeling and measurement of operation parameters suitable for arc ignition and H- production at 2 Hz is of paramount importance and must be understood prior to the implementation of discharge ion sources in the Linac4 accelerator. In its original configuration, the ISIS H- source delivers beam only if the repetition rate is above 12.5 Hz, this paper describes the implementation of a temperature control of the discharge region aiming at lower repetition rate operation. The experimental results of the modified source successfully operated down to 1.6 Hz and providing 30 mA H- pulses of 0.75 ms duration are presented. A thermal modeling of the ISIS ion source gives insight to the relevant parameters. The analysis demonstrates the adaptability of discharge sources for the operating conditions of the Linac4.

  9. 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

  10. 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...

  11. Microscopic cluster model of {alpha}+n, {alpha}+p, {alpha}+ {sup 3}He, and {alpha}+{alpha} elastic scattering from a realistic effective nuclear interaction

    SciTech Connect

    Dohet-Eraly, J.; Baye, D.

    2011-07-15

    An effective nucleon-nucleon interaction adapted to cluster-model calculations of collisions is derived from the realistic Argonne potential AV18 with the unitary correlation operator method. The unitary correlation is determined from the {alpha}+{alpha} elastic phase shifts calculated in a cluster approach by the generator coordinate method coupled with the microscopic R-matrix method. With this interaction, the elastic phase shifts for the {alpha}+n, {alpha}+p, and {alpha}+{sup 3}He collisions are calculated within the same model. Without further adjustment, a good agreement with experimental data is obtained with a small model space.

  12. Phase transition and conduction mechanism in Pb{sub 2}Na{sub 0.8}R{sub 0.2}Nb{sub 4.8}Fe{sub 0.2}O{sub 15} material (R=rare earth)

    SciTech Connect

    Bouziane, M.; Taibi, M.; Boukhari, A.

    2013-11-15

    Electrical properties of Pb{sub 2}Na{sub 0.8}Eu{sub 0.2}Nb{sub 4.8}Fe{sub 0.2}O{sub 15} tungsten bronze compound were investigated. Ferroelectric phase transition of diffuse type is observed at 395 °C. Conductivity study as a function of temperature (RT-600 °C) and at three different frequencies (10, 100 and 1000 kHz) suggests the existence of dominant ionic conduction. The rise of ac conductivity on increasing temperature supports the NTCR (negative temperature coefficient of resistance) behaviour of the material. The activation energies have been evaluated from ac conductivity using Arrhenius equation and discussed. Different conduction mechanisms were identified. For comparison, the conducting properties of Pb{sub 2}Na{sub 0.8}R{sub 0.2}Nb{sub 4.8}Fe{sub 0.2}O{sub 15} (R=Dy, Nd, La) were also investigated. - Graphical abstract: Thermal evolution of lnσ{sub ac} of Pb{sub 2}Na{sub 0.8}Eu{sub 0.2}Nb{sub 4.8}Fe{sub 0.2}O{sub 15} at selected frequencies. Display Omitted - Highlights: • We found that TB compounds exhibit a diffuse type of first- order transition. • A negative temperature coefficient of resistance (NTCR) behaviour is observed. • Three conduction mechanisms were identified: n-and/or p-type at low temperatures. • The conduction mechanism in the studied compounds is very complex.

  13. Alpha glucosidase inhibitors.

    PubMed

    Kalra, Sanjay

    2014-04-01

    Alpha glucosidase inhibitors (AGIs) are a unique class of anti-diabetic drugs. Derived from bacteria, these oral drugs are enzyme inhibitors which do not have a pancreato -centred mechanism of action. Working to delay carbohydrate absorption in the gastrointestinal tract, they control postprandial hyperglycaemia and provide unquestioned cardiovascular benefit. Specially suited for a traditional Pakistani carbohydrate-rich diet, AGIs have been termed the 'untapped diamonds' of diabetology. The use of these oral antidiabetic drugs (OADs) that target pathophysiology in the early stages of type 2 diabetes, notably to reduce postprandial hyperglycaemia and hyperinsulinaemia will inevitably increase with time. This review describes the history of their development, mechanism of action, basic and clinical pharmacology, and suggests practical, evidence-based guidance for their optimal use. PMID:24864650

  14. DFT CONFORMATIONAL STUDIES OF ALPHA-MALTOTRIOSE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent DFT optimization studies on alpha-maltose improved our understanding of the preferred conformations of alpha-maltose and the present study extends these studies to alpha-maltotriose with three alpha-D-glucopyranose residues linked by two alpha-[1-4] bridges, denoted herein as DP-3's. Combina...

  15. Alpha particle emitters in medicine

    SciTech Connect

    Fisher, D.R.

    1989-09-01

    Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 ({sup 211}At) and natural bismuth-212 ({sup 212}Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 ({sup 223}Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs.

  16. Prothymosin alpha in human blood.

    PubMed Central

    Panneerselvam, C; Haritos, A A; Caldarella, J; Horecker, B L

    1987-01-01

    The major cross-reacting peptide in human plasma detected with a radioimmunoassay (RIA) for thymosin alpha 1 was identified as prothymosin alpha, based on its elution properties in gel-filtration chromatography and its amino acid composition after purification by HPLC. A small quantity (less than 10%) of the total cross-reacting material was recovered in fractions corresponding to lower molecular weight thymosin alpha 1-like peptides. The total quantity of cross-reacting material detected in human blood, expressed as thymosin alpha 1 equivalents, was 11-14 pmol/ml (approximately 90% was recovered in the leukocyte fraction, approximately 10% was in the plasma fraction, and 1-2% was in the erythrocyte fraction). The peptide present in leukocytes was also identified as prothymosin alpha. After correction for the 5-times lower molar reactivity of prothymosin alpha in the thymosin alpha 1 RIA employed in these experiments, we estimate that the content of prothymosin alpha in human blood is 55-70 pmol/ml (0.6-0.8 microgram/ml). The relatively small quantities recovered in the erythrocyte and plasma fractions may be attributed to contamination of the former by leukocytes or to leakage from leukocytes into the plasma. PMID:3474615

  17. EEG Alpha Power and Intelligence.

    ERIC Educational Resources Information Center

    Doppelmayr, M.; Klimesch, W.; Stadler, W.; Pollhuber, D.; Heine, C.

    2002-01-01

    Tested whether alpha power in different sub-bands is selectively related to intelligence. For 74 Austrian subjects, the EEG was recorded during a resting session and 2 different intelligence tests were performed. Findings show a strong positive correlation between intelligence and alpha power. (SLD)

  18. Low-frequency sounds and psychological tests at 7, 18, and 40 Hz

    NASA Astrophysics Data System (ADS)

    Damijan, Zbigniew; Kasprzak, Cezary; Panuszka, Ryszard

    2001-05-01

    Research included the results of tests aimed to determine how LFN (low-frequency noise) with the dominating frequency (7 Hz at 120 dB, 18 Hz at 120 dB, and 40 Hz at 110 dB) influences human brain potentials and understanding the dependency of results achieved in psychological questionnaires. The psychological questionnaires (EPQ-R Eysencks and SSS-5 Zuckermans) were analyzed. Presented issue existences difference, relative influence LFN on human biopotentials, dependence from acquired results in ranges EPQ-R Eysencks and SSS-5 Zuckermans. The test included 96 experiments. Standard EEG potentials, ECG potentials, and EDP (dermal) were recorded before, during and after subject's 35-min exposures to LFN. Evident differences in changed bio-signals especially in EEG subject's dispersion, were easily determined and correlated to questionnaire reports.

  19. Low frequency, ca. 40 Hz, pulse trains recorded in the humpback whale assembly in Hawaii.

    PubMed

    Darling, James D

    2015-11-01

    During studies of humpback whale song and social sounds in Hawaii, bouts of low frequency (ca. 40 Hz) pulses were periodically recorded. One example was made near an active group of eight adults (included 22 bouts, 2-13 s long, over 90 min); another close to an adult male-female pair (12 bouts, 9-93 s long, over 22 min). The mean peak and center frequencies (39 to 40 Hz) and bandwidth (13 Hz) were similar in both, but the organization of the pulses differed. Song components, social sounds, bubble trains, or other species do not provide a ready explanation for this sound. PMID:26627813

  20. 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.

  1. Large Granular Lymphocytic (LGL) Leukemia in Rats Exposed to Intermittent 60 Hz Magnetic Fields

    SciTech Connect

    Anderson, Larry E.); Morris, James E.); Miller, Douglas L.); Ebi, K L.; Sasser, Lyle B.)

    2001-04-01

    An animal model for large granular lymphocytic (LGL) leukemia in male Fischer 344 rats utilized to determine whether magnetic field exposure can be shown to influence the progression of leukemia. We previously reported that exposure to continuous 60 Hz 1 mT magnetic fields did not significantly alter the clinical progression of LGL leukemia in young male rats following inspection of spleen cells from donor leukemic rats. Results presented here extend those studies with the objectives to (1) replicate the previous study of continuous 60-Hz magnetic field exposures but using fewer LGL cells in the inoculum, and (2) determine if intermittent 60-Hz magnetic fields can alter the clinical progression of leukemia.

  2. 2- to 3-kHz continuum emissions as possible indications of global heliospheric 'breathing'

    NASA Technical Reports Server (NTRS)

    Grzedzielski, S.; Lazarus, A. J.

    1993-01-01

    The paper analyzes the main features of 2- to 3-kHz heliospheric emissions in the context of a general heliospheric 'breathing' as inferred from the Voyager 2 solar wind average ram pressure data. Triggers for the three 3-kHz emission events seen to date are suggested, and good agreement is obtained in timing and expected postshock frequency for termination shock distances of about 90 AU. It is suggested that the visibility of the individual 3-kHz events and their observed upward frequency drift are enhanced when the postulated global heliospheric expansion results in the formation of a transient, compressed external plasma barrier around the heliopause that prevents radiation escape for several months. The average termination shock distance is estimated to be in the range 80-90 AU.

  3. Alpha Schottky junction energy source

    NASA Astrophysics Data System (ADS)

    Litz, Marc S.; Fan, Zhaoyang; Carroll, James J.; Bayne, Stephen

    2012-06-01

    Isotope batteries offer solutions for long-lived low-power sensor requirements. Alpha emitting isotopes have energy per decay 103 times that of beta emitters. Alpha particles are absorbed within 20 μm of most materials reducing shielding mitigation. However, damage to materials from the alphas limits their practical use. A Schottky Barrier Diode (SBD) geometry is considered with an alpha emitting contact-layer on a diamond-like crystal semiconductor region. The radiation tolerance of diamond, the safety of alpha particles, combined with the internal field of the SBD is expected to generate current useful for low-power electronic devices over decades. Device design parameters and calculations of the expected current are described.

  4. Suppressed alpha oscillations predict intelligibility of speech and its acoustic details.

    PubMed

    Obleser, Jonas; Weisz, Nathan

    2012-11-01

    Modulations of human alpha oscillations (8-13 Hz) accompany many cognitive processes, but their functional role in auditory perception has proven elusive: Do oscillatory dynamics of alpha reflect acoustic details of the speech signal and are they indicative of comprehension success? Acoustically presented words were degraded in acoustic envelope and spectrum in an orthogonal design, and electroencephalogram responses in the frequency domain were analyzed in 24 participants, who rated word comprehensibility after each trial. First, the alpha power suppression during and after a degraded word depended monotonically on spectral and, to a lesser extent, envelope detail. The magnitude of this alpha suppression exhibited an additional and independent influence on later comprehension ratings. Second, source localization of alpha suppression yielded superior parietal, prefrontal, as well as anterior temporal brain areas. Third, multivariate classification of the time-frequency pattern across participants showed that patterns of late posterior alpha power allowed best for above-chance classification of word intelligibility. Results suggest that both magnitude and topography of late alpha suppression in response to single words can indicate a listener's sensitivity to acoustic features and the ability to comprehend speech under adverse listening conditions. PMID:22100354

  5. Suppressed Alpha Oscillations Predict Intelligibility of Speech and its Acoustic Details

    PubMed Central

    Weisz, Nathan

    2012-01-01

    Modulations of human alpha oscillations (8–13 Hz) accompany many cognitive processes, but their functional role in auditory perception has proven elusive: Do oscillatory dynamics of alpha reflect acoustic details of the speech signal and are they indicative of comprehension success? Acoustically presented words were degraded in acoustic envelope and spectrum in an orthogonal design, and electroencephalogram responses in the frequency domain were analyzed in 24 participants, who rated word comprehensibility after each trial. First, the alpha power suppression during and after a degraded word depended monotonically on spectral and, to a lesser extent, envelope detail. The magnitude of this alpha suppression exhibited an additional and independent influence on later comprehension ratings. Second, source localization of alpha suppression yielded superior parietal, prefrontal, as well as anterior temporal brain areas. Third, multivariate classification of the time–frequency pattern across participants showed that patterns of late posterior alpha power allowed best for above-chance classification of word intelligibility. Results suggest that both magnitude and topography of late alpha suppression in response to single words can indicate a listener's sensitivity to acoustic features and the ability to comprehend speech under adverse listening conditions. PMID:22100354

  6. 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

  7. 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.

  8. 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.

  9. Visuo-attentional and sensorimotor alpha rhythms are related to visuo-motor performance in athletes.

    PubMed

    Del Percio, Claudio; Babiloni, Claudio; Bertollo, Maurizio; Marzano, Nicola; Iacoboni, Marco; Infarinato, Francesco; Lizio, Roberta; Stocchi, Massimiliano; Robazza, Claudio; Cibelli, Giuseppe; Comani, Silvia; Eusebi, Fabrizio

    2009-11-01

    This study tested the two following hypotheses: (i) compared with non-athletes, elite athletes are characterized by a reduced cortical activation during the preparation of precise visuo-motor performance; (ii) in elite athletes, an optimal visuo-motor performance is related to a low cortical activation. To this aim, electroencephalographic (EEG; 56 channels; Be Plus EB-Neuro) data were recorded in 18 right-handed elite air pistol shooters and 10 right-handed non-athletes. All subjects performed 120 shots. The EEG data were spatially enhanced by surface Laplacian estimation. With reference to a baseline period, power decrease/increase of alpha rhythms during the preshot period indexed the cortical activation/deactivation (event-related desynchronization/synchronization, ERD/ERS). Regarding the hypothesis (i), low- (about 8-10 Hz) and high-frequency (about 10-12 Hz) alpha ERD was lower in amplitude in the elite athletes than in the non-athletes over the whole scalp. Regarding the hypothesis (ii), the elite athletes showed high-frequency alpha ERS (about 10-12 Hz) larger in amplitude for high score shots (50%) than for low score shots; this was true in right parietal and left central areas. A control analysis confirmed these results with another indicator of cortical activation (beta ERD, about 20 Hz). The control analysis also showed that the amplitude reduction of alpha ERD for the high compared with low score shots was not observed in the non-athletes. The present findings globally suggest that in elite athletes (experts), visuo-motor performance is related to a global decrease of cortical activity, as a possible index of spatially selective cortical processes ("neural efficiency"). PMID:19350556

  10. 20 kHz main inverter unit. [for space station power supplies

    NASA Technical Reports Server (NTRS)

    Hussey, S.

    1989-01-01

    A proof-of-concept main inverter unit has demonstrated the operation of a pulse-width-modulated parallel resonant power stage topology as a 20-kHz ac power source driver, showing simple output regulation, parallel operation, power sharing and short-circuit operation. The use of a two-stage dc input filter controls the electromagnetic compatibility (EMC) characteristics of the dc power bus, and the use of an ac harmonic trap controls the EMC characteristics of the 20-kHz ac power bus.

  11. 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.

  12. High-average-power 100-Hz repetition rate table-top soft x-ray lasers

    NASA Astrophysics Data System (ADS)

    Rocca, Jorge J.; Reagan, Brendan A.; Wernsing, Keith; Wang, Yong; Yin, Liang; Wang, Shoujun; Berrill, Mark; Woolston, Mark R.; Curtis, Alden H.; Furch, Federico J. A.; Shlyaptsev, Vyacheslav N.; Luther, Brad M.; Patel, Dinesh; Marconi, Mario C.; Menoni, Carmen S.

    2013-09-01

    The table-top generation of high average power coherent soft x-ray radiation in a compact set up is of high interest for numerous applications. We have demonstrated the generation of bright soft x-ray laser pulses at 100 Hz repetition rate with record-high average power from compact plasma amplifiers excited by an ultrafast diode-pumped solid state laser. Results of compact λ=18.9nm Ni-like Mo and λ=13.9nm Ni-like Ag lasers operating at 100 Hz repetition rate are discussed.

  13. 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. PMID:25768130

  14. Development of a compact efficient 10 Hz 20 TW Ti:sapphire laser system with a 1 kHz regenerative amplifier

    SciTech Connect

    Zhang Jun; Suzuki, Masayuki; Baba, Motoyoshi; Wei Zhiyi; Wang Zhaohua; Wang Peng; Zhang Jie; Zheng Jiaan; Kuroda, Hiroto

    2007-05-01

    We have constructed a compact efficient Ti:sapphire laser system that generates30 fs,630 mJ pulses at a repetition rate of10 Hz. A new geometry for a single-stage multipass power amplifier is proposed that greatly weakens and even makes use of thermal lensing. Such geometry can realize high output in a single-stage power amplifier; otherwise at least two-stage power amplifiers are required.The new configuration simplifies the laser system and reduces the cost. The key point in this design is that the beam spot size evolution is considered in combination with the pulse amplification.

  15. Genetics Home Reference: alpha-mannosidosis

    MedlinePlus

    ... Me Understand Genetics Home Health Conditions alpha-mannosidosis alpha-mannosidosis Enable Javascript to view the expand/collapse boxes. Download PDF Open All Close All Description Alpha-mannosidosis is a rare inherited disorder that causes ...

  16. Discovery of kHz Quasi-periodic Oscillations in the Z Source Cygnus X-2

    NASA Astrophysics Data System (ADS)

    Wijnands, Rudy; Homan, Jeroen; van der Klis, Michiel; Kuulkers, Erik; van Paradijs, Jan; Lewin, Walter H. G.; Lamb, Frederick K.; Psaltis, Dimitrios; Vaughan, Brian

    1998-02-01

    During observations with the Rossi X-Ray Timing Explorer from 1997 June 31 to July 3 we discovered two simultaneous kHz quasi-periodic oscillations (QPOs) near 500 and 860 Hz in the low-mass X-ray binary and Z source Cygnus X-2. In the X-ray color-color diagram and hardness-intensity diagram (HID), a clear Z track was traced out, which shifted in the HID within 1 day to higher count rates at the end of the observation. Z track shifts are well known to occur in Cyg X-2 our observation for the first time catches the source in the act. A single kHz QPO peak was detected at the left end of the horizontal branch (HB) of the Z track, with a frequency of 731+/-20 Hz and an amplitude of 4.7+0.8-0.6% rms in the energy band 5.0-60 keV. Further to the right on the HB, at somewhat higher count rates, an additional peak at 532+/-43 Hz was detected with an rms amplitude of 3.0+1.0-0.7%. When the source moved down the HB, thus when the inferred mass accretion rate increased, the frequency of the higher frequency QPO increased to 839+/-13 Hz, and its amplitude decreased to 3.5+0.4-0.3% rms. The higher frequency QPO was also detected on the upper normal branch (NB) with an rms amplitude of 1.8+0.6-0.4% and a frequency of 1007+/-15 Hz; its peak width did not show a clear correlation with inferred mass accretion rate. The lower frequency QPO was most of the time undetectable, with typical upper limits of 2% rms; no conclusion on how this QPO behaved with mass accretion rate can be drawn. If the peak separation between the QPOs is the neutron star spin frequency (as required in some beat-frequency models), then the neutron star spin period is 2.9+/-0.2 ms (346+/-29 Hz). This discovery makes Cyg X-2 the fourth Z source that displays kHz QPOs. The properties of the kHz QPOs in Cyg X-2 are similar to those of other Z sources. Simultaneous with the kHz QPOs, the well-known horizontal-branch QPOs (HBOs) were visible in the power spectra. At the left end of the HB, the second harmonic of

  17. The New X-ray Mapping: X-ray Spectrum Imaging above 100 kHz Output Count Rate with the Silicon Drift Detector

    NASA Astrophysics Data System (ADS)

    Newbury, Dale E.

    2006-02-01

    Electron-excited X-ray mapping is a key operational mode of the scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometry (EDS). The popularity of X-ray mapping persists despite the significant time penalty due to the relatively low output count rates, typically less than 25 kHz, that can be processed with the conventional EDS. The silicon drift detector (SDD) uses the same measurement physics, but modifications to the detector structure permit operation at a factor of 5 10 times higher than conventional EDS for the same resolution. Output count rates as high as 500 kHz can be achieved with 217 eV energy resolution (at MnK[alpha]). Such extraordinarily high count rates make possible X-ray mapping through the method of X-ray spectrum imaging, in which a complete spectrum is captured at each pixel of the scan. Useful compositional data can be captured in less than 200 s with a pixel density of 160 × 120. Applications to alloy and rock microstructures, ultrapure materials with rare inclusions, and aggregate particles with complex chemistry illustrate new approaches to characterization made practical by high-speed X-ray mapping with the SDD. a b

  18. Final report on key comparison CCAUV.A-K5: pressure calibration of laboratory standard microphones in the frequency range 2 Hz to 10 kHz

    NASA Astrophysics Data System (ADS)

    Avison, Janine; Barham, Richard

    2014-01-01

    This document and the accompanying spreadsheets constitute the final report for key comparison CCAUV.A-K5 on the pressure calibration of laboratory standard microphones in the frequency range from 2 Hz to 10 kHz. Twelve national measurement institutes took part in the key comparison and the National Physical Laboratory piloted the project. Two laboratory standard microphones IEC type LS1P were circulated to the participants and results in the form of regular calibration certificates were collected throughout the project. One of the microphones was subsequently deemed to have compromised stability for the purpose of deriving a reference value. Consequently the key comparison reference value (KCRV) has been made based on the weighted mean results for sensitivity level and for sensitivity phase from just one of the microphones. Corresponding degrees of equivalence (DoEs) have also been calculated and are presented. 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).

  19. 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).

  20. COOMET pilot comparison 473/RU-a/09: Comparison of hydrophone calibrations in the frequency range 250 Hz to 200 kHz

    NASA Astrophysics Data System (ADS)

    Yi, Chen; Isaev, A. E.; Yuebing, Wang; Enyakov, A. M.; Teng, Fei; Matveev, A. N.

    2011-01-01

    A description is given of the COOMET project 473/RU-a/09: a pilot comparison of hydrophone calibrations at frequencies from 250 Hz to 200 kHz between Hangzhou Applied Acoustics Research Institute (HAARI, China)—pilot laboratory—and Russian National Research Institute for Physicotechnical and Radio Engineering Measurements (VNIIFTRI, Designated Institute of Russia of the CIPM MRA). Two standard hydrophones, B&K 8104 and TC 4033, were calibrated and compared to assess the current state of hydrophone calibration of HAARI (China) and Russia. Three different calibration methods were applied: a vibrating column method, a free-field reciprocity method and a comparison method. The standard facilities of each laboratory were used, and three different sound fields were applied: pressure field, free-field and reverberant field. The maximum deviation of the sensitivities of two hydrophones between the participants' results was 0.36 dB. Main text. To reach the main text of this paper, click on Final Report. The final report has been peer-reviewed and approved for publication by the CCAUV-KCWG.

  1. 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

  2. Beyond 10 J/ 2 Hz LUCIA current status with cryogenic amplifier

    NASA Astrophysics Data System (ADS)

    Lucianetti, A.; Novo, T.; Vincent, B.; Albach, D.; Chanteloup, J.-C.

    2011-06-01

    More than 10 Joules at 2 Hz were recently obtained from the LUCIA laser system based on diode-pumped Yb:YAG active mirrors. This achievement is the result of careful management of both Amplified Spontaneous Emission and thermal effects in laser amplifiers. Future developments including a cryogenically-cooled active mirror are also presented.

  3. 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 PRIVATE LAND MOBILE RADIO SERVICES Standards for Special Frequencies or Frequency Bands § 90.253 Use...

  4. 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 PRIVATE LAND MOBILE RADIO SERVICES Standards for Special Frequencies or Frequency Bands § 90.253 Use...

  5. Deficits in high- (>60 Hz) gamma-band oscillations during visual processing in schizophrenia

    PubMed Central

    Grützner, Christine; Wibral, Michael; Sun, Limin; Rivolta, Davide; Singer, Wolf; Maurer, Konrad; Uhlhaas, Peter J.

    2013-01-01

    Current theories of the pathophysiology of schizophrenia have focused on abnormal temporal coordination of neural activity. Oscillations in the gamma-band range (>25 Hz) are of particular interest as they establish synchronization with great precision in local cortical networks. However, the contribution of high gamma (>60 Hz) oscillations toward the pathophysiology is less established. To address this issue, we recorded magnetoencephalographic (MEG) data from 16 medicated patients with chronic schizophrenia and 16 controls during the perception of Mooney faces. MEG data were analysed in the 25–150 Hz frequency range. Patients showed elevated reaction times and reduced detection rates during the perception of upright Mooney faces while responses to inverted stimuli were intact. Impaired processing of Mooney faces in schizophrenia patients was accompanied by a pronounced reduction in spectral power between 60–120 Hz (effect size: d = 1.26) which was correlated with disorganized symptoms (r = −0.72). Our findings demonstrate that deficits in high gamma-band oscillations as measured by MEG are a sensitive marker for aberrant cortical functioning in schizophrenia, suggesting an important aspect of the pathophysiology of the disorder. PMID:23532620

  6. Analysis of the genome of the sexually transmitted insect virus Hz-2V

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hz-2V is an insect DNA virus closely related to the baculoviruses that grow to high titers in insect cells and produces high yields of virus progeny. The capacity of this virus to replicate to high titers in insect cells may allow the use of this virus for production of large amount of proteins. Th...

  7. A megavolt Marx generator with pulse recurrence frequency of 200 Hz

    SciTech Connect

    Bushlyakov, A.I.; Rukin, S.N.; Slovikovskii, B.G.

    1995-10-01

    The design problems related to repetitive Marx generators are discussed. The circuitry and structure of a megavolt nanosecond Marx generator with a pulse recurrence frequency of 200 Hz operating at an average power of 80 kW are described. The results of generator tests are given.

  8. ACTION OF 50 HZ MAGNETIC FIELDS ON NEURITE OUTGROWTH IN PHEOCHROMOCYTOMA CELLS

    EPA Science Inventory

    This study tests the capacity of 50-Hz magnetic and electric fields to stimulate neurite outgrowth in PC-12D cells, a cell line which originated from a pheochromocytoma in rat adrenal medulla. he cells were plated on collagen-coated plastic petri dishes and exposed to sinusoidal ...

  9. 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.

  10. 47 CFR 15.221 - Operation in the band 525-1705 kHz.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... do not exceed 15 uV/m, as measured at a distance of 47,715/(frequency in kHz) meters (equivalent to... of an AM broadcast station on a college or university campus or on the campus of any other...

  11. 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.

  12. 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.

  13. 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. PMID:27035630

  14. Observations of the radio noise background in the frequency range 150-180 kHz

    NASA Astrophysics Data System (ADS)

    Knowles, S. H.; Kelly, F. J.; Waltman, W. B.; Odenwald, S.

    1985-05-01

    Observations were made of the radio noise background in the frequency range 150-180 kHz to provide reference data for the design of the ground wave emergency network system. These observations were undertaken at Nanjemoy, Maryland, during early summer 1983 and included 41 days of data recording. The noise environment was found to be dominated by impulsive thunderstorm noise. A typical nighttime mean noise power spectral density was 1×10-15 W m-2 Hz-1 (noise factor of 107 dB above kT0), while a typical daytime level was at least 14 dB quieter. However, the daytime level was at times significantly higher, especially during the presence of a local thunderstorm front. During local thunderstorm activity, impulses with peak power spectral density of 1×10-14 W m-2 Hz-1 were observed frequently, while the most energetic pulse detected during our monitoring period had a peak power spectral density of 6.8×10-14 W m-2 Hz-1 (Fa = 125 dB). Sample amplitude probability distributions and time probability distributions are presented for day/quiet, night, and thunderstorm conditions. Agreement with the mean noise level predictions of CCIR report 322 is satisfactory within the accuracy limits of the CCIR data.

  15. Observation of 20-400 kHz fluctuations in the U-3M torsatron

    NASA Astrophysics Data System (ADS)

    Dreval, M. B.; Yakovenko, Yu. V.; Sorokovoy, E. L.; Slavnyj, A. S.; Pavlichenko, R. O.; Kulaga, A. E.; Zamanov, N. V.; Hirose, A.

    2016-02-01

    First observations of quasi-coherent fluctuations in the frequency range of 20-400 kHz in Alfvén-wave-heated plasmas of the U-3M torsatron are presented. The excitation conditions of these modes depend on the radio frequency antenna type and the plasma density, the appearance of the modes correlating with the presence of both suprathermal electrons and high-energy ions in the plasma, which supports our opinion that the modes are excited by energetic particles. Complicated evolution of the mode frequencies with abrupt changes at the instants of plasma confinement transitions is observed at the initial stage of each discharge. The frequencies become stable at the stage of the plasma current flattop. Raw estimates show that toroidicity-induced Alfvén eigenmodes could be responsible for the 150-400 kHz fluctuations. Low-frequency 20-70 kHz bursts are observed during plasma confinement transitions. The poloidal mode number of one of these bursts with the frequency of 20 kHz burst was determined to be m = 2. This mode rotated in the electron diamagnetic rotation direction with a frequency lower than the geodesic acoustic mode frequency and can be identified as a drift-sound-type mode.

  16. Alpha-particle spectrometer experiment

    NASA Technical Reports Server (NTRS)

    Gorenstein, P.; Bjorkholm, P.

    1972-01-01

    Mapping the radon emanation of the moon was studied to find potential areas of high activity by detection of radon isotopes and their daughter products. It was felt that based on observation of regions overflown by Apollo spacecraft and within the field of view of the alpha-particle spectrometer, a radon map could be constructed, identifying and locating lunar areas of outgassing. The basic theory of radon migration from natural concentrations of uranium and thorium is discussed in terms of radon decay and the production of alpha particles. The preliminary analysis of the results indicates no significant alpha emission.

  17. Development of myasthenia gravis after interferon alpha therapy.

    PubMed

    Gurtubay, I G; Morales, G; Aréchaga, O; Gállego, J

    1999-03-01

    Interferon (IFN) alpha is now used in the treatment of some malignant diseases and chronic viral hepatitis. There have been several reports of development of autoantibodies and autoimmune diseases or the deterioration of preexisting disorders in patients under treatment. We enclose a case of myasthenia gravis (MG) which developed after six weeks of treatment as fluctuating bilateral ptosis, intermittent diplopia, and mild weakness of limb and neck muscles. A test dose of edrophonium chloride was administered, resulting in improved muscle strength. Elevated anti acetylcholine receptor (AChR) antibody titer was found. Single fiber electromyography showed an increased jitter from extensor digitorum communis, frequently accompanied by transmission blocking. Repetitive electric 3 Hz stimulation of the abductor pollicis brevis muscle, revealed an abnormal decrement of 28% in compound motor action potential. Myasthenia gravis was diagnosed and the patient was given pyridostigmine, immunoglobulines and prednisone with benefit. Six months latter he developed an acute myasthenic crisis with severe respiratory failure and high anti AChR antibody titer. IFN-alpha can induce MG or simply manifests a preexisting subclinical disease, but otherwise its therapeutic efficacy in MG has been shown in experimental and clinical studies. Autoimmune mechanisms, as the release of different cytokines as IFN, by immunocompetent cells, may be involved in the pathogenesis of both MG and chronic active hepatitis. Autoantibody production against postsynaptic membrane structures by IFN-alpha could be the underlying pathophysiology. PMID:10207675

  18. 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

  19. Negative selection of semimature CD4+8-HSA+ thymocytes requires the BH3-only protein Bim but is independent of death receptor signaling

    PubMed Central

    Villunger, Andreas; Marsden, Vanessa S.; Zhan, Yifan; Erlacher, Miriam; Lew, Andrew M.; Bouillet, Philippe; Berzins, Stuart; Godfrey, Dale I.; Heath, William R.; Strasser, Andreas

    2004-01-01

    T cell receptor/CD3 ligation induces apoptosis in semimature CD4+8-HSA+ thymocytes, and this helps establish immunological tolerance and constitutes one of the safeguards against autoimmune disease. We analyzed several knockout and transgenic mouse lines and found that T cell receptor/CD3-ligation-induced killing of semimature thymocytes occurred independently of Fas and “death receptor” signaling in general but required the proapoptotic BH3-only protein Bim and could be inhibited by Bcl-2. Loss of Apaf-1 or caspase-9, which act downstream of the Bcl-2 family protein family, provided only minor protection, indicating that the “apoptosome” functions as an amplifier rather than as an essential initiator of this death program. These results reveal the mechanisms of apoptosis in negative selection of semimature thymocytes and have implications for immunological tolerance and autoimmunity. PMID:15118096

  20. Chemical and Thermoelectric Properties of Hot Pressed and Spark Plasma Sintered Type-I Clathrate Ba8Cu4.8Si41.2

    NASA Astrophysics Data System (ADS)

    Yan, X.; Populoh, S.; Weidenkaff, A.; Rogl, P.; Paschen, S.

    2016-03-01

    Nanostructuring has been considered as an effective way to reduce the thermal conductivity and enhance the thermoelectric performance in different material systems. Here, we present the chemical and thermoelectric properties of the nanostructured bulk type-I clathrate Ba8Cu4.8Si41.2. The samples were prepared by consolidating ball-milled nanopowders either by hot pressing or by spark plasma sintering. Fine powders and high sintering temperatures are needed to reach a high bulk density and high thermoelectric performance in the sintered samples. The highest ZT of 0.3 at 870 K is achieved in the most dense sample sintered at 800°C by hot pressing. Further improvement is expected if smaller grain sizes could be stabilized.

  1. Discovery and synthesis of new UV-induced intrastrand C(4-8)G and G(8-4)C photolesions.

    PubMed

    Münzel, Martin; Szeibert, Claudia; Glas, Andreas F; Globisch, Daniel; Carell, Thomas

    2011-04-13

    UV irradiation of cellular DNA leads to the formation of a number of defined mutagenic DNA lesions. Here we report the discovery of new intrastrand C(4-8)G and G(8-4)C cross-link lesions in which the C(4) amino group of the cytosine base is covalently linked to the C(8) position of an adjacent dG base. The structure of the novel lesions was clarified by HPLC-MS/MS data for UV-irradiated DNA in combination with chemical synthesis and direct comparison of the synthetic material with irradiated DNA. We also report the ability to generate the lesions directly in DNA with the help of a photoactive precursor that was site-specifically incorporated into DNA. This should enable detailed chemical and biochemical investigations of these lesions. PMID:21425860

  2. Complexation of 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-dienium bromide with copper salts

    NASA Astrophysics Data System (ADS)

    Huddin, Ameera Aqeela Salleh; Yamin, Bohari M.; Yusoff, Siti Fairus M.

    2014-09-01

    Copper complexes have been synthesized with 14-membered macrocyclic 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-dienium bromide (Me6N4H4)Br2 as ligand having six methyl groups and two double bonds located in diagonal position. These complexes were characterized by microelemental analysis, Fourier Transform Infrared (FTIR) and Ultraviolet-Visible (UV-VIS) spectroscopies. The chemical analysis and spectroscopic data is supported by chemical crystallographic study showed that one of the synthesized copper complex with CuCl2 consists of [Cu(Me6N4H2)] dication, two bromide counter anions and 2 water molecules of crystallisation. Thermogravimetry Analysis (TGA) showed that the complex is stable up to about 200°C before gradually decomposed up to 400°C.

  3. Fabrication of high-resolution 4,8(2) -type archimedean nanolattices composed of solution processable spin cross-over Fe(II) metallosupramolecular polymers.

    PubMed

    Venkataramudu, Uppari; Chandrasekhar, Naisa; Basak, Supratim; Prasad, Muvva D; Chandrasekar, Rajadurai

    2015-04-01

    This paper presents the synthesis of two highly soluble Fe(II) metallosupramolecular polymers with two counter anions from a novel back-to-back coupled hybrid ligand. The spin cross-over (SCO) temperature of polymers with BF4 and ClO4 counter anions is T1/2 = 313 K and T1/2 = 326 K, respectively. By following the top-down approach, one of the polymers (with ClO4 counter anion) is successfully solution processed using a lithographically controlled wetting technique to create laser readable high-resolution Archimedean (4,8(2) ) nanolattices (consist of diamagnetic octagons and SCO squares). The thickness and top area of each SCO square are ≈75 nm and ≈2 × 2 μm(2) , respectively. PMID:25594848

  4. 4.8 Gbit/s 16-QAM-OFDM transmission based on compact 450-nm laser for underwater wireless optical communication.

    PubMed

    Oubei, Hassan M; Duran, Jose R; Janjua, Bilal; Wang, Huai-Yung; Tsai, Cheng-Ting; Chi, Yu-Cheih; Ng, Tien Khee; Kuo, Hao-Chung; He, Jr-Hau; Alouini, Mohamed-Slim; Lin, Gong-Ru; Ooi, Boon S

    2015-09-01

    We experimentally demonstrate an underwater wireless optical communications (UWOC) employing 450-nm TO-9 packaged and fiber-pigtailed laser diode (LD) directly encoded with an orthogonal frequency division multiplexed quadrature amplitude modulation (QAM-OFDM) data. A record data rate of up to 4.8 Gbit/s over 5.4-m transmission distance is achieved. By encoding the full 1.2-GHz bandwidth of the 450-nm LD with a 16-QAM-OFDM data, an error vector magnitude (EVM) of 16.5%, a signal-to-noise ratio (SNR) of 15.63 dB and a bit error rate (BER) of 2.6 × 10(-3), well pass the forward error correction (FEC) criterion, were obtained. PMID:26368431

  5. Performance of a small, graphite electrode, multistage depressed collector with a 500-W, continuous wave, 4.8- to 9.6-GHz traveling wave tube

    NASA Technical Reports Server (NTRS)

    Ramins, Peter; Lesny, Gary G.; Ebihara, Ben T.; Peet, Shelly

    1988-01-01

    A small, isotropic graphite multistage depressed collector (MDC) and a short permanent magnet refocuser were designed, fabricated, and evaluated in conjunction with a 500-W, continuous-wave (CW), 4.8 to 9.6 GHz traveling wave tube (TWT). A novel performance optimization system and technique were used to optimize the TWT-MDC performance for saturated broad-band operation. The MDC performance was evaluated in both four- and three-stage configurations. Average TWT overall and four-stage collector efficiencies of 43.8 and 82.6 percent, respectively, were obtained for saturated octave-bandwidth operation. The isotropic graphite electrode material performed well, and shows considerable promise. However, considerably more test experience is required before definitive conclusions on its suitability for space and airborne TWT's can be made.

  6. 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.

  7. Direction-Finding Measurements of Heliospheric 2-3 kHz Radio Emissions

    NASA Technical Reports Server (NTRS)

    Gurnett, Donald A.

    1998-01-01

    Using data from the Voyager 1 plasma wave instrument, a series of direction-finding measurements is presented for the intense 1992-93 heliospheric 2- to 3-kHz radio emission event, and several weaker events extending into 1994. Direction-finding measurements can only be obtained during roll maneuvers, which are performed about once every three months. Two parameters can be determined from the roll-induced intensity modulation, the azimuthal direction of arrival (measured around the roll axis), and the modulation index (the peak-to-peak amplitude divided by the peak amplitude). Measurements were made at two frequencies, 1.78 and 3.11 kHz. No roll modulation was observed at 1.78 kHz, which is consistent with an isotropic source at this frequency. In most cases an easily measurable roll modulation was detectable at 3.11 kHz. Although the azimuth angles have considerable scatter, the directions of arrival at 3.11 kHz can be organized into three groups, each of which appears to be associated with a separate upward drifting feature in the radio emission spectrum. The first group, which is associated with the main 1992-93 event, is consistent with a source located near the nose of the heliosphere. The remaining two groups, which occur after the main 1992-93 event, have azimuth angles well away from the nose of the heliosphere. The modulation indexes vary over a large range, from 0.06 to 0.61, with no obvious trend. Although the variations in the directions of arrival and modulation indicies appear to reflect changes in the position and angular size of the source, it is also possible that they could be caused by refraction or scattering due to density structures in the solar wind.

  8. Occupational exposures to high frequency electromagnetic fields in the intermediate range ( >300 Hz-10 MHz).

    PubMed

    Floderus, Birgitta; Stenlund, Carin; Carlgren, Frank

    2002-12-01

    The aim of this study was to identify work situations with electromagnetic fields of 300 Hz-10 MHz and to characterize the occupational exposure. Work place investigations included descriptions of the work environment and physical measurements. We estimated electric (E) and magnetic (H) fields by spot measurements in air, by logged exposure data, and when possible, we recorded induced currents in limbs. The instruments used were Wandel and Golterman EFA-3, NARDA 8718, Holaday HI-3702. The exposure sources comprised five induction furnaces, seven induction heaters, one surface treatment equipment, four units of electronic article surveillance (EAS), and medical devices for surgery and muscle stimulation. The induction furnaces operated at 480 Hz-7 kHz, and the maximum values of logged data varied between 512-2,093 V/m (E field) and 10.5-87.3 A/m (H field). The induction heaters (3.8 kHz-1.25 MHz) also showed high maximum exposure values of both E and H fields. Three EAS units, an electromagnetic plate at a library, a luggage control unit, and an antitheft gate, showed E fields reaching 658-1,069 V/m. The H fields were comparatively lower, except for the antitheft gate (5 and 7.5 kHz) showing a maximum value of 27.2 A/m (recorded during repair). Induced currents of 5-13 mA were measured for the medical devices. The study improves the basis for an exposure assessment for epidemiological studies of long term effects of exposures to high frequency electromagnetic fields. PMID:12395411

  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. Patterning poly(maleic anhydride-co-3,9-divinyl-2,4,8,10-tetraoxaspiro (5.5) undecane) copolymer bioconjugates for controlled release of drugs.

    PubMed

    Nita, Loredana E; Chiriac, Aurica P; Mititelu-Tartau, Liliana; Stoleru, Elena; Doroftei, Florica; Diaconu, Alina

    2015-09-30

    Owing to the special characteristics and abilities polymeric networks have received special interest for a range of biomedical applications especially for drug delivery systems. This study was devoted to preparation of new polymeric compounds based on maleic anhydride and 3,9-divinyl-2,4,8,10-tetraoxaspiro (5.5) undecane copolymer (poly maleic anhydride-co-3,9-divinyl-2,4,8,10-tetraoxaspiro (5.5) undecane) (PMAU) patterned as a network for bioconjugation and tested as drug carrier systems. The PMAU copolymer was improved in its functionality by opening the maleic anhydride ring with different amounts of erythritol, which is free of side effects in regular use and a multifunctional compound, and also confers antioxidant character for the new compounds. The new polymeric matrices were loaded with acetaminophen, codeine and their fixed dose combinations. The investigation demonstrated the capability of the new structures to be used as polymer networks for linking bioactive compounds and to perform controlled delivery. The physico-chemical investigations--Fourier transform infrared spectroscopy (FTIR) spectra, contact angle, zeta potential (ZP - z, PMAU and its derivatives samples loaded with medicines present decreased values of zeta potential attesting the bioconjugate formation and as well their stability), and hydrodynamic radius, near infrared chemical imaging evaluation (new specific bands being registered for bio-conjugate with acetaminophen around of 1150-1200 nm and 1700 nm, and also between 1150 and 1200 nm in case of the codeine bio-conjugate), scanning electron microscopy (SEM) studies, X-ray diffraction analysis--evidenced the formation of the bioconjugates in relation to the chemical composition of the polymer matrices, while in vitro release study and in vivo tests confirm the capacity for drug delivery of the prepared bioactive systems. PMID:26220652

  11. Coupling between the 45 Hz Horizontal-Branch Oscillation and the Normal-Branch Oscillation in Scorpius X-1

    NASA Astrophysics Data System (ADS)

    Yu, Wenfei

    2007-04-01

    The observations of the bright persistent neutron star low-mass X-ray binary (LMXB) Sco X-1 performed with the Rossi X-Ray Timing Explorer (RXTE) show a ~6 Hz normal-branch oscillation (NBO), a ~45 Hz horizontal-branch oscillation (HBO), and twin kilohertz quasi-periodic oscillations (kHz QPOs) on its normal branch simultaneously. We have found that the fractional amplitude of the HBO corresponding to the NBO phase of high flux is 1.1%, while that of the NBO phase of low flux is undetectable, with a 3 σ upper limit of 0.4%, implying that the HBO strength varies with the NBO phase in a manner opposite that of the lower kHz QPO previously found, and suggests that the condition for the generation of the HBO is met when the NBO flux is high. The 6 Hz NBO in Sco X-1 connects the 45 Hz HBO and the twin kHz QPO together, showing a unique picture indicating a coupling between the QPOs, which has never been observed in other neutron star LMXBs. We discuss the implications for current models of the 45 Hz HBO, the 6 Hz NBO, and the twin kHz QPOs.

  12. Binding of tumor necrosis factor alpha to activated forms of human plasma alpha 2 macroglobulin.

    PubMed Central

    Wollenberg, G. K.; LaMarre, J.; Rosendal, S.; Gonias, S. L.; Hayes, M. A.

    1991-01-01

    We tested the hypothesis that human plasma alpha 2 macroglobulin (alpha 2M) is a latent binding glycoprotein for human tumor necrosis factor alpha (TNF-alpha). Human recombinant 125I-TNF-alpha was incubated for 2 hours (37 degrees C) with purified native alpha 2M and with alpha 2M that was modified by reaction with methylamine or various proteinases. 125I-TNF-alpha/alpha 2M complexes were detected by nondenaturing polyacrylamide gel electrophoresis after autoradiography or by liquid chromatography on Superose-6. 125I-TNF-alpha bound strongly but noncovalently to alpha 2M-plasmin and alpha 2M-methylamine. There was minimal binding of 125I-TNF-alpha to native alpha 2M, alpha 2M-trypsin, or alpha 2M-thrombin. A 10(6) molar excess of porcine heparin did not reduce the binding of 125I-TNF-alpha to alpha 2M-methylamine or alpha 2M-plasmin. alpha 2M-plasmin or alpha 2M-methylamine added to human plasma or serum preferentially bound 125I-TNF-alpha in the presence of native alpha 2M. 125I-TNF-alpha also bound to 'fast' alpha-macroglobulins in methylamine-reacted human, rat, mouse, swine, equine, and bovine plasma. However, TNF-alpha, preincubated with either alpha 2M-plasmin or alpha 2M-methylamine, remained a potent necrogen for cultured L929 cells. Purified 125I-TNF-alpha/alpha 2M-plasmin complex injected intravenously in CD-1 mice rapidly cleared from the circulation, unless the alpha 2M-receptor pathway was blocked by coinjection of excess alpha 2M-trypsin. These findings demonstrate that alpha 2M is a latent plasmin-activated binding glycoprotein for TNF-alpha and that TNF-alpha/alpha 2M-plasmin complexes can be removed from the circulation by the alpha 2M-receptor pathway. This suggests that alpha 2M may be an important regulator of the activity and distribution of TNF-alpha in vivo. Images Figure 1 Figure 3 PMID:1704186

  13. Alpha Magnetic Spectrometer (AMS) Overview

    NASA Video Gallery

    The Alpha Magnetic Spectrometer (AMS) is flying to the station on STS-134. The AMS experiment is a state-of-the-art particle physics detector being operated by an international team composed of 60 ...

  14. Genetics Home Reference: alpha thalassemia

    MedlinePlus

    ... in each cell. Each copy is called an allele. For each gene, one allele is inherited from a person's father, and the ... person's mother. As a result, there are four alleles that produce alpha-globin. The different types of ...

  15. International Space Station (ISS) Alpha

    NASA Technical Reports Server (NTRS)

    1994-01-01

    An artist's concept of a fully deployed International Space Station (ISS) Alpha. The ISS-A is a multidisciplinary laboratory, technology test bed, and observatory that will provide an unprecedented undertaking in scientific, technological, and international experiments.

  16. Detecting Alpha-1 Antitrypsin Deficiency.

    PubMed

    Stoller, James K

    2016-08-01

    Alpha-1 antitrypsin deficiency is a widely underrecognized condition, with evidence of persisting long diagnostic delays and patients' frequent need to see multiple physicians before initial diagnosis. Reasons for underrecognition include inadequate understanding of alpha-1 antitrypsin deficiency by physicians and allied health care providers; failure to implement available, guideline-based practice recommendations; and the belief that effective therapy is unavailable. Multiple studies have described both the results of screening and targeted detection of individuals with alpha-1 antitrypsin deficiency, with both varying strategies employed to identify at-risk individuals and varying results of testing. Also, various strategies to enhance detection of affected individuals have been examined, including use of the electronic medical record to prompt testing and empowerment of allied health providers, especially respiratory therapists, to promote testing for alpha-1 antitrypsin deficiency. Such efforts are likely to enhance detection with the expected result that the harmful effects of delayed diagnosis can be mitigated. PMID:27564667

  17. Alpha decay in electron surrounding

    SciTech Connect

    Igashov, S. Yu.; Tchuvil’sky, Yu. M.

    2013-12-15

    The influence of atomic electron shells on the constant of alpha decay of heavy and mediummass nuclei was considered in detail. A method for simultaneously taking into account the change in the potential-barrier shape and the effect of reflection of a diverging Coulomb wave in the classically allowed region was developed. The ratios of decay probabilities per unit time for a bare nucleus and the respective neutral atom were found for some alpha-decaying isotopes.

  18. Lateralization in Alpha-Band Oscillations Predicts the Locus and Spatial Distribution of Attention

    PubMed Central

    Ikkai, Akiko; Dandekar, Sangita; Curtis, Clayton E.

    2016-01-01

    Attending to a task-relevant location changes how neural activity oscillates in the alpha band (8–13Hz) in posterior visual cortical areas. However, a clear understanding of the relationships between top-down attention, changes in alpha oscillations in visual cortex, and attention performance are still poorly understood. Here, we tested the degree to which the posterior alpha power tracked the locus of attention, the distribution of attention, and how well the topography of alpha could predict the locus of attention. We recorded magnetoencephalographic (MEG) data while subjects performed an attention demanding visual discrimination task that dissociated the direction of attention from the direction of a saccade to indicate choice. On some trials, an endogenous cue predicted the target’s location, while on others it contained no spatial information. When the target’s location was cued, alpha power decreased in sensors over occipital cortex contralateral to the attended visual field. When the cue did not predict the target’s location, alpha power again decreased in sensors over occipital cortex, but bilaterally, and increased in sensors over frontal cortex. Thus, the distribution and the topography of alpha reliably indicated the locus of covert attention. Together, these results suggest that alpha synchronization reflects changes in the excitability of populations of neurons whose receptive fields match the locus of attention. This is consistent with the hypothesis that alpha oscillations reflect the neural mechanisms by which top-down control of attention biases information processing and modulate the activity of neurons in visual cortex. PMID:27144717

  19. 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

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

    PubMed

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

    2016-02-01

    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. PMID:25982482

  1. Carrier-envelope phase stabilization of a 16 TW, 10  Hz Ti:sapphire laser.

    PubMed

    Takahashi, Eiji J; Fu, Yuxi; Midorikawa, Katsumi

    2015-11-01

    We propose and demonstrate a simple and promising method for stabilizing the carrier-envelope phase (CEP) of a high-energy ultrashort pulse laser operating at a low repetition rate. The method was successfully applied to a Ti:sapphire laser operating at 10 Hz with 400 mJ pulse energy and 25 fs pulse duration (16 TW). The laser system consists of a 1 kHz front-end preamplifier and a 10 Hz back-end power amplifier. By sampling a 500 Hz reference pulse from a 1 kHz seed pulse, the measured single-shot CEP noise of a 10 Hz amplified pulse is stabilized to 670 mrad rms. Our proposed CEP stabilization concept can be applied to single-shot ultrahigh-power lasers, such as a petawatt laser system. PMID:26512462

  2. Decoding and Reconstructing the Focus of Spatial Attention from the Topography of Alpha-band Oscillations.

    PubMed

    Samaha, Jason; Sprague, Thomas C; Postle, Bradley R

    2016-08-01

    Many aspects of perception and cognition are supported by activity in neural populations that are tuned to different stimulus features (e.g., orientation, spatial location, color). Goal-directed behavior, such as sustained attention, requires a mechanism for the selective prioritization of contextually appropriate representations. A candidate mechanism of sustained spatial attention is neural activity in the alpha band (8-13 Hz), whose power in the human EEG covaries with the focus of covert attention. Here, we applied an inverted encoding model to assess whether spatially selective neural responses could be recovered from the topography of alpha-band oscillations during spatial attention. Participants were cued to covertly attend to one of six spatial locations arranged concentrically around fixation while EEG was recorded. A linear classifier applied to EEG data during sustained attention demonstrated successful classification of the attended location from the topography of alpha power, although not from other frequency bands. We next sought to reconstruct the focus of spatial attention over time by applying inverted encoding models to the topography of alpha power and phase. Alpha power, but not phase, allowed for robust reconstructions of the specific attended location beginning around 450 msec postcue, an onset earlier than previous reports. These results demonstrate that posterior alpha-band oscillations can be used to track activity in feature-selective neural populations with high temporal precision during the deployment of covert spatial attention. PMID:27003790

  3. The role of alpha-rhythm states in perceptual learning: insights from experiments and computational models

    PubMed Central

    Sigala, Rodrigo; Haufe, Sebastian; Roy, Dipanjan; Dinse, Hubert R.; Ritter, Petra

    2014-01-01

    During the past two decades growing evidence indicates that brain oscillations in the alpha band (~10 Hz) not only reflect an “idle” state of cortical activity, but also take a more active role in the generation of complex cognitive functions. A recent study shows that more than 60% of the observed inter-subject variability in perceptual learning can be ascribed to ongoing alpha activity. This evidence indicates a significant role of alpha oscillations for perceptual learning and hence motivates to explore the potential underlying mechanisms. Hence, it is the purpose of this review to highlight existent evidence that ascribes intrinsic alpha oscillations a role in shaping our ability to learn. In the review, we disentangle the alpha rhythm into different neural signatures that control information processing within individual functional building blocks of perceptual learning. We further highlight computational studies that shed light on potential mechanisms regarding how alpha oscillations may modulate information transfer and connectivity changes relevant for learning. To enable testing of those model based hypotheses, we emphasize the need for multidisciplinary approaches combining assessment of behavior and multi-scale neuronal activity, active modulation of ongoing brain states and computational modeling to reveal the mathematical principles of the complex neuronal interactions. In particular we highlight the relevance of multi-scale modeling frameworks such as the one currently being developed by “The Virtual Brain” project. PMID:24772077

  4. Alpha Reactivity to Complex Sounds Differs during REM Sleep and Wakefulness

    PubMed Central

    Ruby, Perrine; Blochet, Camille; Eichenlaub, Jean-Baptiste; Bertrand, Olivier; Morlet, Dominique; Bidet-Caulet, Aurélie

    2013-01-01

    We aimed at better understanding the brain mechanisms involved in the processing of alerting meaningful sounds during sleep, investigating alpha activity. During EEG acquisition, subjects were presented with a passive auditory oddball paradigm including rare complex sounds called Novels (the own first name - OWN, and an unfamiliar first name - OTHER) while they were watching a silent movie in the evening or sleeping at night. During the experimental night, the subjects’ quality of sleep was generally preserved. During wakefulness, the decrease in alpha power (8–12 Hz) induced by Novels was significantly larger for OWN than for OTHER at parietal electrodes, between 600 and 900 ms after stimulus onset. Conversely, during REM sleep, Novels induced an increase in alpha power (from 0 to 1200 ms at all electrodes), significantly larger for OWN than for OTHER at several parietal electrodes between 700 and 1200 ms after stimulus onset. These results show that complex sounds have a different effect on the alpha power during wakefulness (decrease) and during REM sleep (increase) and that OWN induce a specific effect in these two states. The increased alpha power induced by Novels during REM sleep may 1) correspond to a short and transient increase in arousal; in this case, our study provides an objective measure of the greater arousing power of OWN over OTHER, 2) indicate a cortical inhibition associated with sleep protection. These results suggest that alpha modulation could participate in the selection of stimuli to be further processed during sleep. PMID:24260331

  5. 21 CFR 882.1610 - Alpha monitor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Alpha monitor. 882.1610 Section 882.1610 Food and... NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An alpha... electroencephalogram which is referred to as the alpha wave. (b) Classification. Class II (performance standards)....

  6. 21 CFR 882.1610 - Alpha monitor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Alpha monitor. 882.1610 Section 882.1610 Food and... NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An alpha... electroencephalogram which is referred to as the alpha wave. (b) Classification. Class II (performance standards)....

  7. 21 CFR 882.1610 - Alpha monitor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Alpha monitor. 882.1610 Section 882.1610 Food and... NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An alpha... electroencephalogram which is referred to as the alpha wave. (b) Classification. Class II (performance standards)....

  8. 21 CFR 882.1610 - Alpha monitor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Alpha monitor. 882.1610 Section 882.1610 Food and... NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An alpha... electroencephalogram which is referred to as the alpha wave. (b) Classification. Class II (performance standards)....

  9. 21 CFR 882.1610 - Alpha monitor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Alpha monitor. 882.1610 Section 882.1610 Food and... NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An alpha... electroencephalogram which is referred to as the alpha wave. (b) Classification. Class II (performance standards)....

  10. The Hox-4.8 gene is localized at the 5' extremity of the Hox-4 complex and is expressed in the most posterior parts of the body during development.

    PubMed

    Dollé, P; Izpisúa-Belmonte, J C; Boncinelli, E; Duboule, D

    1991-12-01

    We report the isolation and expression pattern of a novel mouse homeobox gene, Hox-4.8. Hox-4.8 is the most 5'-located homeobox gene in the HOX-4 complex. Sequence analysis confirmed that Hox-4.8 is a member of the subfamily of AbdominalB-related Hox-4 genes and revealed strong interspecies conservation. As for the human locus, Hox-4.8 is probably the last Hox gene in this part of the HOX-4 complex. During development, Hox-4.8 transcripts are restricted to the extremities of the embryonic anteroposterior axis and limbs as well as in the developing tail bud and to the most posterior segment of the gut (the rectum). Within the limb mesenchyme, Hox-4.8 is expressed in more posterodistal regions than those of its neighbour Hox-4.7. Hence, Hox-4.8 expression appears to be related to the last significant phenotypic changes towards the extremities of the embryonic body and limb axes. PMID:1685889

  11. Binding of actin to lens alpha crystallins

    NASA Technical Reports Server (NTRS)

    Gopalakrishnan, S.; Takemoto, L.; Spooner, B. S. (Principal Investigator)

    1992-01-01

    Actin has been coupled to a cyanogen bromide-activated Sepharose 4B column, then tested for binding to alpha, beta, and gamma crystallin preparations from the bovine lens. Alpha, but not beta or gamma, crystallins bound to the actin affinity column in a time dependent and saturable manner. Subfractionation of the alpha crystallin preparation into the alpha-A and alpha-B species, followed by incubation with the affinity column, demonstrated that both species bound approximately the same. Together, these studies demonstrate a specific and saturable binding of lens alpha-A and alpha-B with actin.

  12. The effects of morphine and morphine conditioned context on 50 kHz ultrasonic vocalisation in rats.

    PubMed

    Hamed, Adam; Taracha, Ewa; Szyndler, Janusz; Krząścik, Paweł; Lehner, Małgorzata; Maciejak, Piotr; Skórzewska, Anna; Płaźnik, Adam

    2012-04-15

    The 50 kHz ultrasonic vocalisations (USVs) that are emitted by rats are dependent on activity of dopaminergic neurons projecting from the ventral tegmental area to the limbic and cortical structures. According to many experimental data, emission of the 50 kHz USV reflects a positive emotional state. The appetitive calls are also emitted in response to the administration of drugs of abuse, e.g., cocaine or amphetamine (AMPH), or in a reply to a positively conditioned context. However, there is no strong evidence in the literature that morphine can also modulate 50 kHz USVs. The aim of this paper is to study the effects of morphine and morphine-conditioned context on 50 kHz USVs, using spontaneously or drug-modulated 50 kHz USVs. Our results showed that acute administration of morphine to rats after withdrawal period inhibited the emission of 50 kHz USVs. The stimulating effect of morphine-conditioned context on 50 kHz USVs appeared on the post-withdrawal challenge day immediately before drug injection, 14 days after the last episode of morphine-induced context conditioning. The context-induced 50 kHz USVs can be used as a sensitive test for drug dependency. The current study also shows that 50 kHz USVs can be useful tool for studying the mechanisms of long lasting central effects of morphine. PMID:22326697

  13. Brain-wide slowing of spontaneous alpha rhythms in mild cognitive impairment

    PubMed Central

    Garcés, Pilar; Vicente, Raul; Wibral, Michael; Pineda-Pardo, Jose Ángel; López, Maria Eugenia; Aurtenetxe, Sara; Marcos, Alberto; de Andrés, Maria Emiliana; Yus, Miguel; Sancho, Miguel; Maestú, Fernando; Fernández, Alberto

    2013-01-01

    The neurophysiological changes associated with Alzheimer's Disease (AD) and Mild Cognitive Impairment (MCI) include an increase in low frequency activity, as measured with electroencephalography or magnetoencephalography (MEG). A relevant property of spectral measures is the alpha peak, which corresponds to the dominant alpha rhythm. Here we studied the spatial distribution of MEG resting state alpha peak frequency and amplitude values in a sample of 27 MCI patients and 24 age-matched healthy controls. Power spectra were reconstructed in source space with linearly constrained minimum variance beamformer. Then, 88 Regions of Interest (ROIs) were defined and an alpha peak per ROI and subject was identified. Statistical analyses were performed at every ROI, accounting for age, sex and educational level. Peak frequency was significantly decreased (p < 0.05) in MCIs in many posterior ROIs. The average peak frequency over all ROIs was 9.68 ± 0.71 Hz for controls and 9.05 ± 0.90 Hz for MCIs and the average normalized amplitude was (2.57 ± 0.59)·10−2 for controls and (2.70 ± 0.49)·10−2 for MCIs. Age and gender were also found to play a role in the alpha peak, since its frequency was higher in females than in males in posterior ROIs and correlated negatively with age in frontal ROIs. Furthermore, we examined the dependence of peak parameters with hippocampal volume, which is a commonly used marker of early structural AD-related damage. Peak frequency was positively correlated with hippocampal volume in many posterior ROIs. Overall, these findings indicate a pathological alpha slowing in MCI. PMID:24409145

  14. 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.

  15. Orbit compensation for the time-varying elliptically polarized wiggler with switching frequency at 100 hz

    SciTech Connect

    Singh, O.; Krinsky, S.

    1997-07-01

    In October 1996, the elliptically polarized wiggler, installed in the X13 straight section of the NSLS X-ray ring, was commissioned at an operating frequency of 100 hz. This wiggler generates circularly polarized photons in the energy range of 0.1 to 10 keV with AC modulation of polarization helicity. The vertical magnetic field is produced by a hybrid permanent magnet structure, and the horizontal magnetic field is generated by an electromagnet capable of switching at frequencies up to 100 hz. Here, the authors discuss the compensation of the residual vertical and horizontal orbit motion utilizing a time-domain algorithm employing a function generator to drive trim coils at the wiggler ends, and the wideband high precision orbit measurement system of the X-ray ring. The residual orbit motion has been reduced to a level below 1 micron, and the device has been run in regular operations with no negative effect on other users.

  16. 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.

  17. A beta2-frequency (20–30 Hz) oscillation in nonsynaptic networks of somatosensory cortex

    PubMed Central

    Roopun, Anita K.; Middleton, Steven J.; Cunningham, Mark O.; LeBeau, Fiona E. N.; Bibbig, Andrea; Whittington, Miles A.; Traub, Roger D.

    2006-01-01

    Beta2 frequency (20–30 Hz) oscillations appear over somatosensory and motor cortices in vivo during motor preparation and can be coherent with muscle electrical activity. We describe a beta2 frequency oscillation occurring in vitro in networks of layer V pyramidal cells, the cells of origin of the corticospinal tract. This beta2 oscillation depends on gap junctional coupling, but it survives a cut through layer 4 and, hence, does not depend on apical dendritic electrogenesis. It also survives a blockade of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors or a blockade of GABAA receptors that is sufficient to suppress gamma (30–70 Hz) oscillations in superficial cortical layers. The oscillation period is determined by the M type of K+ current. PMID:17030821

  18. Extended high-frequency audiometry (9,000-20,000 Hz). Usefulness in audiological diagnosis.

    PubMed

    Rodríguez Valiente, Antonio; Roldán Fidalgo, Amaya; Villarreal, Ithzel M; García Berrocal, José R

    2016-01-01

    Early detection and appropriate treatment of hearing loss are essential to minimise the consequences of hearing loss. In addition to conventional audiometry (125-8,000 Hz), extended high-frequency audiometry (9,000-20,000 Hz) is available. This type of audiometry may be useful in early diagnosis of hearing loss in certain conditions, such as the ototoxic effect of cisplatin-based treatment, noise exposure or oral misunderstanding, especially in noisy environments. Eleven examples are shown in which extended high-frequency audiometry has been useful in early detection of hearing loss, despite the subject having a normal conventional audiometry. The goal of the present paper was to highlight the importance of the extended high-frequency audiometry examination for it to become a standard tool in routine audiological examinations. PMID:26025356

  19. 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.

  20. Study of the decomposition of wet SF6, subjected to 50-Hz ac corona discharges

    NASA Astrophysics Data System (ADS)

    Derdouri, A.; Casanovas, J.; Hergli, R.; Grob, R.; Mathieu, J.

    1989-03-01

    Mixtures of SF6 (100 kPa≤PSF6≤400 kPa) and water (concentrations ranging from 240 to 2000 vpm) have been submitted to point-plane 50-Hz ac corona discharges. The only stable gaseous by-products detected, either by gas-phase chromatography or gas chromatography-mass spectrometry techniques, were SOF2 and SO2F2. The variation of their concentrations as a function of the discharge current value (3-25 μA rms), the charge transported (0.15-1.5 C), the water content, the SF6 pressure, and the gap spacing (1.5-5 mm) have been studied. The results indicate that, at least in our experimental conditions, the 50-Hz ac corona discharges behave more like negative than like positive dc corona.

  1. Zero-phonon-line pumped 100-kHz Yb:YAG thin disk regenerative amplifier

    NASA Astrophysics Data System (ADS)

    Miura, Taisuke; Smrž, Martin; Nagisetty, Siva Sankar; Novák, Ondřej; Chyla, Michal; Severová, Patricie; Endo, Akira; Mocek, Tomáś

    2014-02-01

    We are developing 100-kHz picosecond Yb:YAG thin disk regenerative amplifier with 500-W average power for medical and industrial applications. Especially in case of the next generation of semiconductor lithography, high average power solid-state laser with picosecond pulse duration as pre pulse source is a key element to realize 1-kW EUV lithography source. We compared the output characteristics of CW laser operation pumped at 940-nm and 969-nm, and measured the surface temperature of thin disk. We found that the surface temperature of thin disk pumped at 960-nm was much lower than that pumped at 940-nm. We obtained 83-W output from thin disk regenerative amplifier at the repetition rate of 100-kHz pumped at 969-nm. The measured pulse duration was 1.9-ps.

  2. Comparative study of cable construction for 20 kHz power distribution

    NASA Astrophysics Data System (ADS)

    Putney, William W.; McKay, Scott J.; Freeman, Kenneth A.

    Problems associated with transmission of 20 kHz power because of skin effect are well known. At 20 kHz, classical cable constructions (i.e., solid circular and those based on circular layup of multiple noninsulated strands) larger than 18 gauge utilize only a portion of the conductor cross section to carry current. The unused metal internal to the conduction layer ('skin') can represent considerable excess weight, volume, and material cost for relatively large diameters. In this paper several special constructions have been studied to facilitate making the best choice for given current levels and cable lengths to minimize or eliminate the wasted copper. Among the candidate constructions were Litz, flat conductor, coaxial, and multiple twisted pair. Selection criteria were efficiency of copper utilization, flexibility, EMI, impedances, volume, weight, manufacturing and assembly costs, and whether existing, new, or modified existing termination techniques and hardware would be used.

  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. 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.

  5. 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.

  6. All-fiber-integrated linearly polarized fiber laser delivering 476  μJ, 50  kHz, nanosecond pulses for ultrasonic generation.

    PubMed

    Zhang, Pengfei; Xu, Xiaodong; Yu, Hailong; Su, Rongtao; Wang, Xiaolin; Yang, Lijia

    2016-05-10

    We demonstrate a high-energy linearly polarized pulsed fiber laser for ultrasonic generation based on a master oscillator power amplification (MOPA) scheme, which delivers nanosecond pulses with duration of 4.8 ns and pulse energy of 476 μJ at the repetition rate of 50 kHz. The MOPA is seeded by a gain switch semiconductor laser diode at 1064 nm. In the pre-amplification stages, a double-pass amplification structure is designed and successfully applied to amplify the low-power seed laser for the consideration of suppressing amplified spontaneous emission, decreasing the number of amplification stages, and reducing the nonlinear effects. A highly ytterbium-doped fiber is utilized in the main amplifier to shorten the fiber length and reduce the fiber nonlinearity. The average power is finally boosted to 23.8 W with corresponding optical-to-optical efficiency of 66.9% and a polarization extinction rate of ∼10.5  dB. The corresponding peak power is calculated to be 87.1 kW. Finally, the established laser system is successfully used for ultrasonic generation based on a line excitation configuration and grating excitation configuration, and clear surface acoustic wave signals are detected. Many potential applications in laser ultrasonics can be foreseen. PMID:27168281

  7. Cosmic chronometers: constraining the equation of state of dark energy. I: H(z) measurements

    SciTech Connect

    Stern, Daniel; Jimenez, Raul; Verde, Licia; Kamionkowski, Marc; Stanford, S. Adam E-mail: raul@icc.ub.edu E-mail: kamion@tapir.caltech.edu

    2010-02-01

    We present new determinations of the cosmic expansion history from red-envelope galaxies. We have obtained for this purpose high-quality spectra with the Keck-LRIS spectrograph of red-envelope galaxies in 24 galaxy clusters in the redshift range 0.2 < z < 1.0. We complement these Keck spectra with high-quality, publicly available archival spectra from the SPICES and VVDS surveys. We improve over our previous expansion history measurements in Simon et al. (2005) by providing two new determinations of the expansion history: H(z) = 97±62 km sec{sup −1} Mpc{sup −1} at z ≅ 0.5 and H(z) = 90±40 km sec{sup −1} Mpc{sup −1} at z ≅ 0.9. We discuss the uncertainty in the expansion history determination that arises from uncertainties in the synthetic stellar-population models. We then use these new measurements in concert with cosmic-microwave-background (CMB) measurements to constrain cosmological parameters, with a special emphasis on dark-energy parameters and constraints to the curvature. In particular, we demonstrate the usefulness of direct H(z) measurements by constraining the dark-energy equation of state parameterized by w{sub 0} and w{sub a} and allowing for arbitrary curvature. Further, we also constrain, using only CMB and H(z) data, the number of relativistic degrees of freedom to be 4±0.5 and their total mass to be < 0.2 eV, both at 1σ.

  8. 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.

  9. 115 kHz tuning repetition rate ultrahigh-speed wavelength-swept semiconductor laser

    PubMed Central

    Oh, W. Y.; Yun, S. H.; Tearney, G. J.; Bouma, B. E.

    2009-01-01

    We demonstrate an ultrahigh-speed wavelength-swept semiconductor laser using a polygon-based wavelength scanning filter. With a polygon rotational speed of 900 revolutions per second, a continuous wavelength tuning rate of 9200 nm/ms and a tuning repetition rate of 115 kHz were achieved. The wavelength tuning range of the laser was 80 nm centered at 1325 nm, and the average polarized output power was 23 mW. PMID:16350273

  10. 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.

  11. 5 Hz repetitive transcranial magnetic stimulation over the ipsilesional sensory cortex enhances motor learning after stroke

    PubMed Central

    Brodie, Sonia M.; Meehan, Sean; Borich, Michael R.; Boyd, Lara A.

    2014-01-01

    Sensory feedback is critical for motor learning, and thus to neurorehabilitation after stroke. Whether enhancing sensory feedback by applying excitatory repetitive transcranial magnetic stimulation (rTMS) over the ipsilesional primary sensory cortex (IL-S1) might enhance motor learning in chronic stroke has yet to be investigated. The present study investigated the effects of 5 Hz rTMS over IL-S1 paired with skilled motor practice on motor learning, hemiparetic cutaneous somatosensation, and motor function. Individuals with unilateral chronic stroke were pseudo-randomly divided into either Active or Sham 5 Hz rTMS groups (n = 11/group). Following stimulation, both groups practiced a Serial Tracking Task (STT) with the hemiparetic arm; this was repeated for 5 days. Performance on the STT was quantified by response time, peak velocity, and cumulative distance tracked at baseline, during the 5 days of practice, and at a no-rTMS retention test. Cutaneous somatosensation was measured using two-point discrimination. Standardized sensorimotor tests were performed to assess whether the effects might generalize to impact hemiparetic arm function. The active 5 Hz rTMS + training group demonstrated significantly greater improvements in STT performance {response time [F(1, 286.04) = 13.016, p < 0.0005], peak velocity [F(1, 285.95) = 4.111, p = 0.044], and cumulative distance [F(1, 285.92) = 4.076, p = 0.044]} and cutaneous somatosensation [F(1, 21.15) = 8.793, p = 0.007] across all sessions compared to the sham rTMS + training group. Measures of upper extremity motor function were not significantly different for either group. Our preliminary results suggest that, when paired with motor practice, 5 Hz rTMS over IL-S1 enhances motor learning related change in individuals with chronic stroke, potentially as a consequence of improved cutaneous somatosensation, however no improvement in general upper extremity function was observed. PMID:24711790

  12. A modified commercial Ti:sapphire laser with 4 kHz rms linewidth

    NASA Astrophysics Data System (ADS)

    Haubrich, D.; Wynands, R.

    1996-02-01

    We have modified a commercial Ti:sapphire laser to allow optical phase stabilization to an extremely stable semiconductor laser, which in turn is locked to a Doppler-free resonance in a cesium vapor cell. For time scales from 10 μs up to several hours the combined system has a rms linewidth of 4 kHz with respect to the cesium resonance. The system allows the resolution of extremely narrow resonances in a cloud of trapped atoms.

  13. 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

  14. 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.

  15. 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.

  16. Effects of 60-Hz electric fields on embryo and chick development, growth, and behavior. Final report

    SciTech Connect

    Not Available

    1985-07-01

    The objective of this study was to utilize an avian model to determine the effects of 60-Hz electric fields on embryo and chick development. A specially designed incubator allowed simultaneous incubation of control eggs and eggs exposed to 60-Hz electric fields. Two series of experimental voltages were utilized for this study. In Series 1, the subject eggs were exposed to 20, 40, 60, 80, and 100 kV/m fields and, in Series 2, eggs were exposed to 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, and 100 kV/m. Data were collected on mortality, malformation, and growth (weight) of 7- and 14-day-old embryos after continuous exposure to electric fields. Eggs were also incubated, exposed to electric fields, and hatched in order to collect data on chick weights at one day and at 2, 4, and 6 weeks after hatching. Behavior tests on newly hatched chicks that had been exposed to electric fields during development were also performed. The results indicated no consistent effect of 60-Hz electric fields, varying from 0.1 to 100 kV/m, on mortality, malformations, weights, bone growth (metatarsal length), or behavior of embryos or chicks. This study strongly suggests that within the scope of this project, there is no consistent direct effect of 60 Hz electric fields on the health and well-being of avian embryos. A dose-response analysis was also utilized in which all the data in each series, for each age of the embryos, were simultaneously evaluated in a statistical model. This analysis demonstrated that there is no significant dose-response of electric fields on 7- and 14-day-old embryo and 1-day-old chick weights. 24 refs., 21 figs., 56 tabs.

  17. 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. PMID:26915487

  18. 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.

  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. Dependence of kHz quasi-periodic oscillation frequencies on accretion-related parameters

    NASA Astrophysics Data System (ADS)

    Hakan Erkut, M.; 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.

  1. 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.

  2. 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

  3. 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.

  4. Developmental effects of magnetic field (50 Hz) in combination with ionizing radiation and chemical teratogens.

    PubMed

    Pafková, H; Jerábek, J; Tejnorová, I; Bednár, V

    1996-11-01

    The influence of a 50 Hz magnetic field (MF) on avian and mammalian embryogenesis, the MF level and vector, as well as the effect of exposure to MF (50 Hz, 10 mT) in combination with X-rays has been recently reported [2,3]. No significant alterations of chick or rat embryogenesis were found after repeated exposures to 50 Hz MF at 10 mT or 6 microT or with different vectors. However, X-ray chick embryotoxicity was significantly affected by repeated exposures of developing organisms to MF. A strong dependence of effect on the type of interaction was revealed. A decrease of X-ray induced teratogenicity was observed when MF preceded X-ray exposure (indirect interaction), while MF exposure applied immediately after X-ray radiation (direct interaction) non-significantly potentiated adverse developmental effects of ionizing radiation. This study deals with the effects of MF in combination with insulin or tetracycline. Exposure of chick embryos to MF influenced the sensitivity of embryonic morphogenetic systems to the subsequently administered chemical teratogens, insulin and/or tetracycline. A protective effect of MF was detected similarly as in the case of indirect interaction with ionizing radiation. PMID:8920754

  5. Microstructural modifications induced by rapid thermal annealing in plasma deposited SiOxNyHz films

    NASA Astrophysics Data System (ADS)

    del Prado, A.; San Andrés, E.; Mártil, I.; González-Díaz, G.; Bravo, D.; López, F. J.; Fernández, M.; Martínez, F. L.

    2003-07-01

    The effect of rapid thermal annealing (RTA) processes on the structural properties of SiOxNyHz films was investigated. The samples were deposited by the electron cyclotron resonance plasma method, using SiH4, O2 and N2 as precursor gases. For SiOxNyHz films with composition close to that of SiO2, which have a very low H content, RTA induces thermal relaxation of the lattice and improvement of the structural order. For films of intermediate composition and of compositions close to SiNyHz, the main effect of RTA is the release of H at high temperatures (T>700 °C). This H release is more significant in films containing both Si-H and N-H bonds, due to cooperative reactions between both kinds of bonds. In these films the degradation of structural order associated to H release prevails over thermal relaxation, while in those films with only N-H bonds, thermal relaxation predominates. For annealing temperatures in the 500-700 °C range, the passivation of dangling bonds by the nonbonded H in the films and the transition from the paramagnetic state to the diamagnetic state of the K center result in a decrease of the density of paramagnetic defects. The H release observed at high annealing temperatures is accompanied by an increase of density of paramagnetic defects.

  6. Discovery of 800 HZ Quasi-Periodic Oscillations in 4U 1608-52

    NASA Astrophysics Data System (ADS)

    Berger, M.; van der Klis, M.; van Paradijs, J.; Lewin, W. H. G.; Lamb, F.; Vaughan, B.; Kuulkers, E.; Augusteijn, T.; Zhang, W.; Marshall, F. E.; Swank, J. H.; Lapidus, I.; Lochner, J. C.; Strohmayer, T. E.

    1996-09-01

    We present results of Rossi X-Ray Timing Explorer observations of the low-mass X-ray binary and atoll source 4U 1608-52 made over 9 days during the decline of an X-ray intensity outburst in 1996 March. A fast-timing analysis shows a strong and narrow quasi-periodic oscillation (QPO) peak at frequencies between 850 and 890 Hz on March 3 and 6, as well as a broad peak around 690 Hz on March 9. Observations on March 12 show no significant signal. On March 3, the X-ray spectrum of the QPO is quite hard; its strength increases steadily from 5% at ~2 keV to ~20% at ~12 keV. The QPO frequency varies between 850 and 890 Hz on that day, and the peak widens and its rms decreases with centroid frequency in a way very similar to the well-known horizontal branch oscillations (HBO) in Z sources. We apply the HBO beat frequency model to atoll sources and suggest that, whereas the model could produce QPOs at the observed frequencies, the lack of correlation we observe between QPO properties and X-ray count rate is hard to reconcile with this model.

  7. 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

  8. Laser-induced incandescence measurements in a fired diesel engine at 3 kHz

    NASA Astrophysics Data System (ADS)

    Boxx, I. G.; Heinold, O.; Geigle, K. P.

    2015-01-01

    Laser-induced incandescence (LII) was performed at 3 kHz in an optically accessible cylinder of a fired diesel engine using a commercially available diode-pumped solid-state laser and an intensified CMOS camera. The resulting images, acquired every 3° of crank angle, enabled the spatiotemporal tracking of soot structures during the expansion/exhaust stroke of the engine cycle. The image sequences demonstrate that soot tends to form in thin sheets that propagate and interact with the in-cylinder flow. These sheets tend to align parallel to the central axis of the cylinder and are frequently wrapped into conical spirals by aerodynamic swirl. Most of the soot is observed well away from the cylinder walls. Quantitative soot measurements were beyond the scope of this study but the results demonstrate the practical utility of using kHz-rate LII to acquire ensemble-averaged statistical data with high crank angle resolution over a complete engine cycle. Based on semi-quantitative measures of soot distribution, it was possible to identify soot dynamics related to incomplete charge exchange. This study shows that long-duration, multi-kHz acquisition rate LII measurements are viable in a fired diesel engine with currently available laser and camera technology, albeit only in the expansion and exhaust phase of the cycle at present. Furthermore, such measurements yield useful insight into soot dynamics and therefore constitute an important new tool for the development and optimization of diesel engine technology.

  9. Observations of backscatter from sand and gravel seafloors between 170 and 250 kHz.

    PubMed

    Weber, Thomas C; Ward, Larry G

    2015-10-01

    Interpreting observations of frequency-dependence in backscatter from the seafloor offers many challenges, either because multiple frequencies are used for different observations that will later be merged or simply because seafloor scattering models are not well-understood above 100 kHz. Hindering the understanding of these observations is the paucity of reported, calibrated acoustic measurements above 100 kHz. This manuscript seeks to help elucidate the linkages between seafloor properties and frequency-dependent seafloor backscatter by describing observations of backscatter collected from sand, gravel, and bedrock seafloors at frequencies between 170 and 250 kHz and at a grazing angle of 45°. Overall, the frequency dependence appeared weak for all seafloor types, with a slight increase in seafloor scattering strength with increasing frequency for an area with unimodal, very poorly to moderately well sorted, slightly granular to granular medium sand with significant amounts of shell debris and a slight decrease in all other locations. PMID:26520300

  10. Compact 4-kHz XeF laser with a multisectional discharge gap

    SciTech Connect

    Andramanov, A V; Kabaev, S A; Lazhintsev, B V; Nor-Arevyan, V A; Selemir, Victor D

    2005-04-30

    A XeF electric-discharge laser with a pulse repetition rate f of up to 4 kHz is developed. The laser electrode unit is based on plate electrodes with inductive-capacitive discharge stabilisation. He and Ne are used as buffer gases, and NF{sub 3} serves as a fluorine donor. A narrow ({approx}1 mm) discharge is achieved; the specific energy deposition per unit length of the active volume is as high as 2 J m{sup -1}. The maximum energy in a laser pulse is {approx}3 mJ for NF{sub 3}-Xe-He and NF{sub 3}-Xe-Ne mixtures at total pressures of 0.8 and 1.2 atm, respectively, and the maximum lasing efficiency is {approx}0.73%. The maximum gas velocity in the working gap is 19 m s{sup -1}. The laser-pulse energy at a high pulse repetition rate (4 kHz) virtually coincides with that obtained at a low repetition rate. The mean output pulse power at f = 4 kHz reaches 12 W, and the rms deviation of the laser-pulse energy is {approx}2.5%. (lasers)

  11. Testing the Interaction Dark Energy Model with H(z) Data

    NASA Astrophysics Data System (ADS)

    Pan, Y.; Li, L.; Cao, S.; Pan, N. N.; Zhang, Y.; Hu, Z. X.

    2015-07-01

    We constrain an interaction dark energy model with the newly revised H(z) data combining with the 7-year baryon acoustic oscillation (BAO) data and the cosmic microwave background (CMB) observations from the Planck first data release using the Markov Chain Monte Carlo (MCMC) method. The marginalized 1σ constraints of the combinations: Ω_{m}=0. 266_{-0. 028}^{+0. 028}(1σ), γ=0.090_{-0.098}^{+0.100}(1σ), w_X=-1. 307_{-0. 269}^{+0.263}(1σ), and H_0=74. 20_{-4.56}^{+4.66}(1σ). The coupling parameter is γ>0 which means the energy is transferred from dark matter to dark energy, and the coincidence problem is slightly alleviated in 1σ range. For comparison, we constrain this model with BAO+CMB observations and H(z) data alone. The results are as follows: (1) The H(z) data could put stricter constraint on the parameter γ. (2) The ΛCDM model remains the best, and the coupling parameter γ is correlated with other model parameters Ω_{m} and H_0. (3) The tension of the constraining results of H_0 between the local distance ladder measurements and the Planck result could be alleviated by considering the interaction term.

  12. Modulation of gene expression by alpha-tocopherol and alpha-tocopheryl phosphate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The naturally occurring vitamin E analogue, alpha-tocopheryl phosphate (alphaTP), has been reported to be more potent in reducing cell proliferation and the expression of the CD36 scavenger receptor than the un-phosphorylated alpha-tocopherol (alpha T). We have now assessed the effects of alpha T an...

  13. Mechanism of alpha-tocopheryl-phosphate (alpha-TP) transport across the cell membrane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have reported that alpha-TP is synthesized and hydrolyzed in animal cells and tissues; it modulates also several cell functions (FRBM 39:970, and UBMB Life, 57:23, 2005). While it is similar to alpha-tocopherol (alpha-T), alpha-TP appears to be more potent than alpha-T in inhibiting cell prolifer...

  14. In vitro studies on the influence of L-ascorbic acid 2-[3,4-dihydro- 2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6yl-hy drogen phosphate] potassium salt on lipid peroxidation and phospholipase A2 activity.

    PubMed

    Kuribayashi, Y; Yoshida, K; Sakaue, T; Okumura, A

    1992-09-01

    The effects of L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2- (4,8,12-trimethyltridecyl)-2H-1-benzopyran-6yl-hydrogen phosphate] potassium salt (EPC-K1, CAS 127061-56-7), a new compound for ischemia-reperfusion injuries, on lipid peroxidation and phospholipase A2 activity were studied in vitro using rat brain homogenates and human plasma. EPC-K1 inhibited phospholipase A2 activity in human plasma in a concentration-dependent manner (IC50 = 7.3 x 10(-4) mol/l), whereas a mixture of alpha-tocopherol and ascorbic acid did not exhibit this effect. In rat brain homogenates, EPC-K1 also inhibited lipid peroxidation in a concentration-dependent manner (IC50 = 2.3 x 10(-6) mol/l). alpha-Tocopherol was less active than EPC-K1. These properties of EPC-K1 suggest that EPC-K1 may prove useful in the treatment of ischemia-reperfusion injuries. PMID:1445471

  15. Oscillatory brain activity in the alpha range is modulated by the content of word-prompted mental imagery

    PubMed Central

    Bartsch, Felix; Hamuni, Gilava; Miskovic, Vladimir; Lang, Peter J.; Keil, Andreas

    2015-01-01

    Mental imagery is a fundamental cognitive process of interest to basic scientists and clinical researchers. This study examined large-scale oscillatory brain activity in the alpha band (8–12 Hz) during language-driven mental imagery using dense-array EEG. Three experiments demonstrated relative increases in alpha amplitude (1) during imagery prompted by words compared to fixation without imagery instruction, (2) during imagery of word content compared to imagery of geometric shapes, and (3) during imagery of emotionally evocative words compared to imagery of less emotionally arousing content. Alpha increases for semantically loaded imagery were observed in parieto-occipital regions, sustained throughout the imagery period. Findings imply that alpha oscillations index active memory and internal cognitive processing, reflecting neural communication in cortical networks representing motor, semantic, and perceptual aspects of the imagined scene. PMID:25616004

  16. Oxidation of iodide and iodine on birnessite (delta-MnO2) in the pH range 4-8.

    PubMed

    Allard, Sébastien; von Gunten, Urs; Sahli, Elisabeth; Nicolau, Rudy; Gallard, Hervé

    2009-08-01

    The oxidation of iodide by synthetic birnessite (delta-MnO(2)) was studied in perchlorate media in the pH range 4-8. Iodine (I(2)) was detected as an oxidation product that was subsequently further oxidized to iodate (IO(3)(-)). The third order rate constants, second order on iodide and first order on manganese oxide, determined by extraction of iodine in benzene decreased with increasing pH (6.3-7.5) from 1790 to 3.1M(-2) s(-1). Both iodine and iodate were found to adsorb significantly on birnessite with an adsorption capacity of 12.7 microM/g for iodate at pH 5.7. The rate of iodine oxidation by birnessite decreased with increasing ionic strength, which resulted in a lower rate of iodate formation. The production of iodine in iodide-containing waters in contact with manganese oxides may result in the formation of undesired iodinated organic compounds (taste and odor, toxicity) in natural and technical systems. The probability of the formation of such compounds is highest in the pH range 5-7.5. For pH <5 iodine is quickly oxidized to iodate, a non-toxic and stable sink for iodine. At pH >7.5, iodide is not oxidized to a significant extent. PMID:19540547

  17. Cr(III)-HMC (HMC = 5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane) Alkynyl Complexes: Preparation and Emission Properties.

    PubMed

    Tyler, Sarah F; Judkins, Eileen C; Song, You; Cao, Fan; McMillin, David R; Fanwick, Phillip E; Ren, Tong

    2016-09-01

    Presented here is the chemistry of Cr(III) alkynyl complexes based on the rac-HMC and meso-HMC ligands (HMC = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane). Thus far, two pairs of cis/trans-[Cr(rac/meso-HMC)(C2R)2]Cl (R = Ph, C2H/C2SiMe3) complexes have been synthesized from reactions between cis/trans-[Cr(rac/meso-HMC)Cl2]Cl and LiC2R. These complexes were characterized using single crystal X-ray diffraction, UV-vis spectroscopy, FT-IR spectroscopy, and fluorimetry. Single crystal X-ray diffraction studies revealed that these complexes adopt a pseudo-octahedral geometry. The electronic spectra of both the cis- and trans-[Cr(rac/meso-HMC)(C4R')2]Cl (R' = H or SiMe3) complexes exhibit d-d bands with pronounced vibronic progression associated with the asymmetric stretch of the Cr-bound C≡C bonds. All of these complexes are phosphorescent and show structured emissions originating from the ligand field excited states. PMID:27529498

  18. Higher weight status of only and last-born children. Maternal feeding and child eating behaviors as underlying processes among 4-8 year olds.

    PubMed

    Mosli, Rana H; Lumeng, Julie C; Kaciroti, Niko; Peterson, Karen E; Rosenblum, Katherine; Baylin, Ana; Miller, Alison L

    2015-09-01

    Birth order has been associated with childhood obesity. The objective of this cross-sectional study was to examine maternal feeding and child eating behaviors as underlying processes for increased weight status of only children and youngest siblings. Participants included 274 low-income 4-8 year old children and their mothers. The dyads completed a videotaped laboratory mealtime observation. Mothers completed the Caregiver's Feeding Styles Questionnaire and the Children's Eating Behavior Questionnaire. Child weight and height were measured using standardized procedures. Path analysis was used to examine associations of birth order, maternal feeding behavior, child eating behavior, and child overweight/obese status. The association between only child status and greater likelihood of overweight/obesity was fully mediated by higher maternal Verbal Discouragement to eat and lower maternal Praise (all p values < 0.05). The association between youngest sibling status and greater likelihood of overweight/obesity was partially mediated by lower maternal Praise and lower child Food Fussiness (all p values < 0.05). Results provide support for our hypothesis that maternal control and support and child food acceptance are underlying pathways for the association between birth order and weight status. Future findings can help inform family-based programs by guiding family counseling and tailoring of recommendations for family mealtime interactions. PMID:26009204

  19. Hydrogen-bonded ring closing and opening of protonated methanol clusters H(+)(CH3OH)(n) (n = 4-8) with the inert gas tagging.

    PubMed

    Li, Ying-Cheng; Hamashima, Toru; Yamazaki, Ryoko; Kobayashi, Tomohiro; Suzuki, Yuta; Mizuse, Kenta; Fujii, Asuka; Kuo, Jer-Lai

    2015-09-14

    The preferential hydrogen bond (H-bond) structures of protonated methanol clusters, H(+)(MeOH)n, in the size range of n = 4-8, were studied by size-selective infrared (IR) spectroscopy in conjunction with density functional theory calculations. The IR spectra of bare clusters were compared with those with the inert gas tagging by Ar, Ne, and N2, and remarkable changes in the isomer distribution with the tagging were found for clusters with n≥ 5. The temperature dependence of the isomer distribution of the clusters was calculated by the quantum harmonic superposition approach. The observed spectral changes with the tagging were well interpreted by the fall of the cluster temperature with the tagging, which causes the transfer of the isomer distribution from the open and flexible H-bond network types to the closed and rigid ones. Anomalous isomer distribution with the tagging, which has been recently found for protonated water clusters, was also found for H(+)(MeOH)5. The origin of the anomaly was examined by the experiments on its carrier gas dependence. PMID:26235389

  20. SEMICONDUCTOR INTEGRATED CIRCUITS: A 3.1-4.8 GHz transmitter with a high frequency divider in 0.18 μm CMOS for OFDM-UWB

    NASA Astrophysics Data System (ADS)

    Renliang, Zheng; Junyan, Ren; Wei, Li; Ning, Li

    2009-12-01

    A fully integrated low power RF transmitter for a WiMedia 3.1-4.8 GHz multiband orthogonal frequency division multiplexing ultra-wideband system is presented. With a separate transconductance stage, the quadrature up-conversion modulator achieves high linearity with low supply voltage. The co-design of different resonant frequencies of the modulator and the differential to single (D2S) converter ensures in-band gain flatness. By means of a series inductor peaking technique, the D2S converter obtains 9 dB more gain without extra power consumption. A divided-by-2 divider is used for carrier signal generation. The measurement results show an output power between -10.7 and -3.1 dBm with 7.6 dB control range, an OIP3 up to 12 dBm, a sideband rejection of 35 dBc and a carrier rejection of 30 dBc. The ESD protected chip is fabricated in the Jazz 0.18 μm RF CMOS process with an area of 1.74 mm2 and only consumes 32 mA current (at 1.8 V) including the test associated parts.

  1. Design, fabrication, and performance of brazed, graphite electrode, multistage depressed collectors with 500-W, continuous wave, 4.8- to 9.6-GHz traveling-wave tubes

    NASA Technical Reports Server (NTRS)

    Ramins, Peter; Ebihara, Ben

    1989-01-01

    A small, isotropic graphite electrode, multistage depressed collector (MDC) was designed, fabricated, and evaluated in conjunction with a 500-W, continuous wave (CW), 4.8- to 9.6-GHz traveling-wave tube (TWT). The carbon electrode surfaces were used to improve the TWT overall efficiency by minimizing the secondary electron emission losses in the MDC. The design and fabrication of the brazed graphite MDC assembly are described. The brazing technique, which used copper braze filler metal, is compatible with both vacuum and the more commonly available hydrogen atmosphere brazing furnaces. The TWT and graphite electrode MCC bakeout, processing, and outgassing characteristics were evaluated and found to be comparable to TWT's equipped with copper electrode MDC's. The TWT and MDC performance was optimized for broadband CW operation at saturation. The average radiofrequency (RF), overall, and MDC efficiencies were 14.9, 46.4, and 83.6 percent, respectively, across the octave operating band. A 1500-hr CW test, conducted without the use of an appendage ion pump, showed no gas buildup and excellent stability of the electrode surfaces.

  2. Workshop on Precision Measurements of $\\alpha_s$

    SciTech Connect

    Bethke, Siegfried; Hoang, Andre H.; Kluth, Stefan; Schieck, Jochen; Stewart, Iain W.; Aoki, S.; Beneke, M.; Bethke, S.; Blumlein, J.; Brambilla, N.; Brodsky, S.; /MIT, LNS

    2011-10-01

    These are the proceedings of the Workshop on Precision Measurements of {alpha}{sub s} held at the Max-Planck-Institute for Physics, Munich, February 9-11, 2011. The workshop explored in depth the determination of {alpha}{sub s}(m{sub Z}) in the {ovr MS} scheme from the key categories where high precision measurements are currently being made, including DIS and global PDF fits, {tau}-decays, electro-weak precision observables and Z-decays, event-shapes, and lattice QCD. These proceedings contain a short summary contribution from the speakers, as well as the lists of authors, conveners, participants, and talks.

  3. Immunodiagnosis of alpha chain disease.

    PubMed Central

    Doe, W F; Danon, F; Seligmann, M

    1979-01-01

    Since the early diagnosis of alpha chain disease (alphaCD)) is essential to successful treatment and to epidemiological studies, the available immunodiagnostic techniques were compared for their sensitivity, specificity and ease of performance on a panel of sixteen sera, comprising ten alphaCD sera and six control sera containing either IgA myeloma protein or high levels of polyclonal IgA. Immunoselection by immunoelectrophoresis into gel containing a specially developed anti-Fabalpha antiserum provided the most sensitive and specific detection system for alphaCD protein. The same technique using anti-light chain antiserum for immunoselection was also highly sensitive, but proved less specific, being prone to false positives with difficult IgA myeloma proteins. Somewhat less sensitive, but specific and simple to perform, was immunoelectrophoresis using an antiserum recognizing the conformational specificities of Fabalpha as well as those of the constant region of alpha chains. Immunoselection using the Ouchterlony or rocket techniques proved to be less sensitive and prone to false positives when some IgA myeloma sera were tested. Images FIG. 1 FIG. 2 FIG. 3 FIG. 4 FIG. 5 FIG. 6 FIG. 7 PMID:113152

  4. Induction, purification and characterization of alpha-N-acetylgalactosaminidase from Aspergillus Niger.

    PubMed

    Weignerová, L; Filipi, T; Manglová, D; Kren, V

    2008-07-01

    A set of filamentous fungi (42 strains) was screened for alpha-N-acetylgalactosaminidase activity, and a series of inducers and different cultivation conditions were tested. Enzyme production by the best producer Aspergillus niger CCIM K2 was optimized and scaled up. alpha-N-Acetylgalactosaminidase was purified to apparent homogeneity by cation exchange chromatography, gel filtration, and chromatofocusing, and basic biochemical data of the enzyme were determined: The native molecular weight was estimated by gel filtration to be approximately 440 kDa, the molecular weight of the subunit was determined to be 76 kDa and the pI = 4.8. The K (M) was 0.73 mmol/l for o-nitrophenyl 2-acetamido-2-deoxy-alpha-D-galactopyranoside (o-NP-alpha-GalNAc), and optimum enzyme activity was achieved at pH 1.8 and 55 degrees C. This alpha-N-acetylgalactosaminidase is a retaining-type glycosidase, and it was N-deglycosylated without any loss of activity. PMID:18443780

  5. Ly{alpha} EMISSION FROM HIGH-REDSHIFT SOURCES IN COSMOS

    SciTech Connect

    Mallery, Ryan P.; Mobasher, Bahram; Hemmati, Shoubaneh; Capak, Peter; Kakazu, Yuko; Masters, Dan; Scoville, Nick; Scarlata, Claudia; Salvato, Mara; McCracken, Henry

    2012-12-01

    We investigate spectroscopically measured Ly{alpha} equivalent widths (EWs) and escape fractions of 244 sources of which 95 are Lyman break galaxies (LBGs) and 106 Lyman alpha emitters (LAEs) at z {approx} 4.2, z {approx} 4.8, and z {approx} 5.6 selected from intermediate and narrowband observations. The sources were selected from the Cosmic Evolution Survey and observed with the DEIMOS spectrograph. We find that the distribution of EWs shows no evolution with redshift for both the LBG selected sources and the intermediate/narrowband LAEs. We also find that the Ly{alpha} escape fraction of intermediate/narrowband LAEs is on average higher and has a larger variation than the escape fraction of LBG selected sources. The escape fraction does not show a dependence with redshift. Similar to what has been found for LAEs at low redshifts, the sources with the highest extinctions show the lowest escape fractions. The range of escape fractions increases with decreasing extinction. This is evidence that the dust extinction is the most important factor affecting the escape of Ly{alpha} photons, but at low extinctions other factors, such as the H I covering fraction and gas kinematics, can be just as effective at inhibiting the escape of Ly{alpha} photons.

  6. 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

  7. 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…

  8. Alpha and theta brain oscillations index dissociable processes in spoken word recognition.

    PubMed

    Strauß, Antje; Kotz, Sonja A; Scharinger, Mathias; Obleser, Jonas

    2014-08-15

    Slow neural oscillations (~1-15 Hz) are thought to orchestrate the neural processes of spoken language comprehension. However, functional subdivisions within this broad range of frequencies are disputed, with most studies hypothesizing only about single frequency bands. The present study utilizes an established paradigm of spoken word recognition (lexical decision) to test the hypothesis that within the slow neural oscillatory frequency range, distinct functional signatures and cortical networks can be identified at least for theta- (~3-7 Hz) and alpha-frequencies (~8-12 Hz). Listeners performed an auditory lexical decision task on a set of items that formed a word-pseudoword continuum: ranging from (1) real words over (2) ambiguous pseudowords (deviating from real words only in one vowel; comparable to natural mispronunciations in speech) to (3) pseudowords (clearly deviating from real words by randomized syllables). By means of time-frequency analysis and spatial filtering, we observed a dissociation into distinct but simultaneous patterns of alpha power suppression and theta power enhancement. Alpha exhibited a parametric suppression as items increasingly matched real words, in line with lowered functional inhibition in a left-dominant lexical processing network for more word-like input. Simultaneously, theta power in a bilateral fronto-temporal network was selectively enhanced for ambiguous pseudowords only. Thus, enhanced alpha power can neurally 'gate' lexical integration, while enhanced theta power might index functionally more specific ambiguity-resolution processes. To this end, a joint analysis of both frequency bands provides neural evidence for parallel processes in achieving spoken word recognition. PMID:24747736

  9. The possible meaning of the upper and lower alpha frequency ranges for cognitive and creative tasks.

    PubMed

    Petsche, H; Kaplan, S; von Stein, A; Filz, O

    1997-06-01

    This study is aimed at verifying the functional independence of two frequency bands within the alpha range. It is based on experiments that examined the role of these two hands with regard to the amount of local electrogenesis (amplitude) and the cooperation of brain areas (coherence) in mental tasks concerning: (1) visual perception and imagery; (2) listening to and composing music; (3) verbal and visual creativity; and (4) aspects of mood. In all experiments EEG were recorded for at least 1 min during each task, separated one from another by at rest periods of at least equal lengths. EEG electrodes were pasted according to the 10/20 system (averaged ear lobes as reference). After FFT power was calculated for all 19 electrodes, coherence was estimated for all possible electrode pairs (i.e. 171). This was done for six frequency ranges between 1.5 and 31.5 Hz, the alpha range having been divided into two (7.5-9 Hz and 9.5-12.5 Hz). The spectral parameters obtained during each task were compared with those of the merged EEG at rest, significant changes (P < or = 0.01-P < or = 0.05) were entered into schematic maps of the brain. Generally, fewer differences were found for amplitude than for coherence. In all four tasks concerning visual perception the clearest differences were found in single person studies. But also in group studies more or less distinct differences were found between alpha 1 and 2. Also in the series with music the two alpha bands did not behave uniformly, nor were uniform features found in the two series of musically trained and untrained subjects. Distinct discrepancies were also found in a verbal and visual imagery task. With respect to mood, only elevated mood was correlated with a decrease of coherence in alpha 2 and an increase of amplitude in alpha 1. This study though hinting at a different functional significance of these two alpha bands, however, does not allow to draw any conclusions as to their distinct functional meanings. Generally

  10. Space Station alpha joint bearing

    NASA Technical Reports Server (NTRS)

    Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

    1987-01-01

    Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

  11. alpha-Thalassemia caused by an unstable alpha-globin mutant.

    PubMed Central

    Liebhaber, S A; Kan, Y W

    1983-01-01

    In a previous study, molecular cloning of the alpha-globin genes from a patient with nondeletion Hb-H disease (genotype--/alpha alpha) showed that a single nucleotide mutation (CTG to CCG) in one of the genes resulted in a leucine to proline substitution. This paper describes the approach we used to detect the abnormal alpha-globin chain. The chain was identified using a cell-free translation system. It turned over rapidly both in vitro and in vivo in the patient's reticulocytes. The unusual feature of this unstable alpha-globin is that the alpha-globin deficiency causes alpha-thalassemia. Simple heterozygotes for this lesion (alpha Pro alpha/alpha alpha) resemble alpha-thalassemia carriers and do not exhibit the hemolytic anemia usually associated with unstable hemoglobins. Images PMID:6826718

  12. Impairments in Background and Event-Related Alpha-Band Oscillatory Activity in Patients with Schizophrenia

    PubMed Central

    Abeles, Ilana Y.; Gomez-Ramirez, Manuel

    2014-01-01

    Studies show that patients with schizophrenia exhibit impaired responses to sensory stimuli, especially at the early stages of neural processing. In particular, patients’ alpha-band (8–14 Hz) event-related desynchronization (ERD) and visual P1 event-related potential (ERP) component tend to be significantly reduced, with P1 ERP deficits greater for visual stimuli biased towards the magnocellular system. In healthy controls, studies show that pre-stimulus alpha (background alpha) plays a pivotal role in sensory processing and behavior, largely by shaping the neural responses to incoming stimuli. Here, we address whether patients’ ERD and P1 deficits stem from impairments in pre-stimulus alpha mechanisms. To address this question we recorded electrophysiological activity in patients with schizophrenia and healthy controls while they engaged in a visual discrimination task with low, medium, and high contrast stimuli. The results revealed a significant decrease in patients’ ERDs, which was largely driven by reductions in pre-stimulus alpha. These reductions were most prominent in right-hemispheric areas. We also observed a systematic relationship between pre-stimulus alpha and the P1 component across different contrast levels. However, this relationship was only observed in healthy controls. Taken together, these findings highlight a substantial anomaly in patients’ amplitude-based alpha background activity over visual areas. The results provide further support that pre-stimulus alpha activity plays an active role in perception by modulating the neural responses to incoming sensory inputs, a mechanism that seems to be compromised in schizophrenia. PMID:24646909

  13. 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.

  14. Startle response of captive North Sea fish species to underwater tones between 0.1 and 64 kHz.

    PubMed

    Kastelein, Ronald A; Heul, Sander van der; Verboom, Willem C; Jennings, Nancy; Veen, Jan van der; de Haan, Dick

    2008-06-01

    World-wide, underwater background noise levels are increasing due to anthropogenic activities. Little is known about the effects of anthropogenic noise on marine fish, and information is needed to predict any negative effects. Behavioural startle response thresholds were determined for eight marine fish species, held in a large tank, to tones of 0.1-64 kHz. Response threshold levels varied per frequency within and between species. For sea bass, the 50% reaction threshold occurred for signals of 0.1-0.7 kHz, for thicklip mullet 0.4-0.7 kHz, for pout 0.1-0.25 kHz, for horse mackerel 0.1-2 kHz and for Atlantic herring 4 kHz. For cod, pollack and eel, no 50% reaction thresholds were reached. Reaction threshold levels increased from approximately 100 dB (re 1 microPa, rms) at 0.1 kHz to approximately 160 dB at 0.7 kHz. The 50% reaction thresholds did not run parallel to the hearing curves. This shows that fish species react very differently to sound, and that generalisations about the effects of sound on fish should be made with care. As well as on the spectrum and level of anthropogenic sounds, the reactions of fish probably depend on the context (e.g. location, temperature, physiological state, age, body size, and school size). PMID:18295877

  15. Thermally stable compositions including 2,4,8,10-tetranitro-5H-pyrido[3',2':4,5][1,2,3]triazolo[1,2-a]benzotriazo- l-6-ium, inner salt

    DOEpatents

    Hiskey, Michael A.; Huynh, My Hang

    2010-01-26

    An explosive formulation including 2,4,8,10-tetranitro-5H-pyrido[3',2':4,5][1,2,3]triazolo[1,2-a]benzotriazo- l-6-ium, inner salt and a high temperature binder is disclosed together with a process of preparing 2,4,8,10-tetranitro-5H-pyrido[3',2':4,5][1,2,3]triazolo[1,2-a]benzotriazo- l-6-ium, inner salt.

  16. Test chamber for alpha spectrometry

    DOEpatents

    Larsen, Robert P.

    1977-01-01

    Alpha emitters for low-level radiochemical analysis by measurement of alpha spectra are positioned precisely with respect to the location of a surface-barrier detector by means of a chamber having a removable threaded planchet holder. A pedestal on the planchet holder holds a specimen in fixed engagement close to the detector. Insertion of the planchet holder establishes an O-ring seal that permits the chamber to be pumped to a desired vacuum. The detector is protected against accidental contact and resulting damage.

  17. Bremsstrahlung in {alpha} Decay Reexamined

    SciTech Connect

    Boie, H.; Scheit, H.; Jentschura, U. D.; Koeck, F.; Lauer, M.; Schwalm, D.; Milstein, A. I.; Terekhov, I. S.

    2007-07-13

    A high-statistics measurement of bremsstrahlung emitted in the {alpha} decay of {sup 210}Po has been performed, which allows us to follow the photon spectra up to energies of {approx}500 keV. The measured differential emission probability is in good agreement with our theoretical results obtained within the quasiclassical approximation as well as with the exact quantum mechanical calculation. It is shown that, due to the small effective electric dipole charge of the radiating system, a significant interference between the electric dipole and quadrupole contributions occurs, which is altering substantially the angular correlation between the {alpha} particle and the emitted photon.

  18. NACA Physicist Studying Alpha Rays

    NASA Technical Reports Server (NTRS)

    1957-01-01

    NACA Physicits studying Alpha Rays in a continuous cloud chamber. A cloud chamber is used by Lewis scientists to obtain information aimed at minimizing undesirable effects of radiation on nuclear-powered aircraft components. Here, alpha particles from a polonium source emit in a flower-like pattern at the cloud chamber's center. The particles are made visible by means of alcohol vapor diffusing from an area at room temperature to an area at minus -78 deg. Centigrade. Nuclear-powered aircraft were never developed and aircraft nuclear propulsion systems were canceled in the early 1960s.

  19. 52 W kHz-linewidth low-noise linearly-polarized all-fiber single-frequency MOPA laser

    NASA Astrophysics Data System (ADS)

    Yang, Changsheng; Xu, Shanhui; Chen, Dan; Zhang, Yuanfei; Zhao, Qilai; Li, Can; Zhou, Kaijun; Feng, Zhouming; Gan, Jiulin; Yang, Zhongmin

    2016-05-01

    An all-fiber Yb-doped kHz-linewidth low-noise linearly polarized single-frequency master-oscillator power-amplifier (MOPA) laser with a stable CW output power of >52 W is demonstrated. By suppressing the intensity noise of the DBR phosphate fiber oscillator, the linewidth of MOPA laser is not noticeably broadened, and an ultra-narrow linewidth of <3 kHz is obtained. Furthermore, the low-noise behavior of MOPA lasers is investigated. A measured relative intensity noise of < -130 dB Hz-1 at frequencies of over 2 MHz, a phase noise above 1 kHz of <5 μrad/Hz1/2, and a signal-to-noise ratio of >63 dB are achieved.

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

    PubMed Central

    Rahman, Anisur; 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

  1. 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

  2. SEMICONDUCTOR INTEGRATED CIRCUITS: A monolithic 3.1-4.8 GHz MB-OFDM UWB transceiver in 0.18-μm CMOS

    NASA Astrophysics Data System (ADS)

    Renliang, Zheng; Xudong, Jiang; Wang, Yao; Guang, Yang; Jiangwei, Yin; Jianqin, Zheng; Junyan, Ren; Wei, Li; Ning, Li

    2010-06-01

    A monolithic RF transceiver for an MB-OFDM UWB system in 3.1-4.8 GHz is presented. The transceiver adopts direct-conversion architecture and integrates all building blocks including a gain controllable wideband LNA, a I/Q merged quadrature mixer, a fifth-order Gm-C bi-quad Chebyshev LPF/VGA, a fast-settling frequency synthesizer with a poly-phase filter, a linear broadband up-conversion quadrature modulator, an active D2S converter and a variable-gain power amplifier. The ESD protected transceiver is fabricated in Jazz Semiconductor's 0.18-μm RF CMOS with an area of 6.1 mm2 and draws a total current of 221 mA from 1.8-V supply. The receiver achieves a maximum voltage gain of 68 dB with a control range of 42 dB in 6 dB/step, noise figures of 5.5-8.8 dB for three sub-bands, and an in-band/out-band IIP3 better than -4 dBm/+9 dBm. The transmitter achieves an output power ranging from -10.7 to -3 dBm with gain control, an output P1dB better than -7.7 dBm, a sideband rejection about 32.4 dBc, and LO suppression of 31.1 dBc. The hopping time among sub-bands is less than 2.05 ns.

  3. Charge transfer and optical properties of wurtzite-type ZnS/(CdS/ZnS){sub n} (n = 2, 4, 8) superlattices

    SciTech Connect

    Zeng, Xianghua Zhang, Wei; Cui, Jieya; Zhou, Min; Chen, Haitao

    2014-02-01

    Graphical abstract: (a) Normalized temperature-dependent PL spectra of ZnS/(CdS/ZnS){sub 4} superlattices from 5 to 300 K and (b) schematic of charge transfer at CdS/ZnS interface. - Highlights: • Wurtzite ZnS/(CdS/ZnS){sub n} superlattices were prepared at 100 °C by pulsed laser deposition. • Surface phonon of ZnS and multiple phonons modes of ZnS and CdS were observed. • The charge transfer of electrons from CdS electron to ZnS holes by excitation energy was found. - Abstract: ZnS/(CdS/ZnS){sub n} (n = 2, 4, 8) superlattices were deposited on sapphire substrate by pulsed laser deposition (PLD) with alternate cadmium sulfide (CdS) and zinc sulfide (ZnS) crystals at 100 °C. The prepared samples with an average thickness of ∼30 nm for ZnS layer and ∼60 nm for CdS layer have a wurtzite-type structure. Surface phonon of ZnS and multiple phonons modes for ZnS and CdS were observed from Raman spectra. PL spectra show a strong green emission at ∼496 nm, two weak emission bands at ∼400 and ∼577 nm, where the emission band at 400 nm was attributed to the recombination of surface defects states to valence, the emission band at 577 nm as the recombination of Cd{sub i}–V{sub Cd} centers, and the strong emission at ∼496 nm is from the charge transfer of electrons from CdS electron to ZnS holes by excitation energy.

  4. Quantitative-Trait Loci on Chromosomes 1, 2, 3, 4, 8, 9, 11, 12, and 18 Control Variation in Levels of T and B Lymphocyte Subpopulations

    PubMed Central

    Hall, M. A.; Norman, P. J.; Thiel, B.; Tiwari, H.; Peiffer, A.; Vaughan, R. W.; Prescott, S.; Leppert, M.; Schork, N. J.; Lanchbury, J. S.

    2002-01-01

    Lymphocyte subpopulation levels are used for prognosis and monitoring of a variety of human diseases, especially those with an infectious etiology. As a primary step to defining the major gene variation underlying these phenotypes, we conducted the first whole-genome screen for quantitative variation in lymphocyte count, CD4 T cell, CD8 T cell, B cell, and natural killer cell numbers, as well as CD4:CD8 ratio. The screen was performed in 15 of the CEPH families that form the main human genome genetic project mapping resource. Quantitative-trait loci (QTLs) that account for significant proportions of the phenotypic variance of lymphocyte subpopulations were detected on chromosomes 1, 2, 3, 4, 8, 9, 11, 12, and 18. The most significant QTL found was for CD4 levels on chromosome 8 (empirical P=.00005). Two regions of chromosome 4 showed significant linkage to CD4:CD8 ratio (empirical P=.00007 and P=.003). A QTL for the highly correlated measures of CD4 and CD19 levels colocalized at 18q21 (both P=.003). Similarly, a shared region of chromosome 1 was linked to CD8 and CD19 levels (P=.0001 and P=.002, respectively). Several of the identified chromosome regions are likely to harbor polymorphic candidate genes responsible for these important human phenotypes. Their discovery has important implications for understanding the generation of the immune repertoire and understanding immune-system homeostasis. More generally, these data show the power of an integrated human gene–mapping approach for heritable molecular phenotypes, using large pedigrees that have been extensively genotyped. PMID:11951176

  5. [Synthesis and Properties of 1,11,15,25-Tetrahydroxy-4,8,18,22-Di (Bridged Dipropionate Carboxyl) Phthalocyanine Copper].

    PubMed

    Xia, Dao-cheng; Li, Wan-cheng; Li, Jie-jun; Wang, Gai-ping; Duan, Hong-wei; Ren, Xu-wen; Feng, Kai; Li, Pei-tao; Wang, Hui-fang; Pu, Gai-qin

    2015-08-01

    In this dissertation, we study the synthesis and character of new substituted Phthalocyanine. Due to the widely application of Pcs in the fields, such as the communication, medical treatment, chemical industry and so on, therefore, they have been a hot topic over several decades by scientists. Nowadays, scientists have prepared thousands of Pcs and their derivatives. However, along with the human society development and the progress in science and technology, the new phthalocyanine with novle characteristics are still the goal of the scientists. In this dissertion, the synthetic methods of the phthlocyanine is improved. The synthesis and characterization of 1,11,15,25-tetrahydroxy-4,8,18,22-di(bridged dipropionate carboxyl) phthalocyanines are reported in this paper. The mixtures of malonic acid and 3,6-dihydroxy-phthalonitrile was added to water under stiriing. Then, a catalyst amount of sulfuric acid was added. The first synthetic precursor, i. e., malonic acid 3,3'-bis(6-hydroxy phthalonitrile) butter, its molecular formula is C19H8N4O6. phthalocyanines was prepared by malonic acid 3,3'-bis(6-hydroxy phthalonitrile) butter and dihydrate zinc acetate, copper acetate monohydrate in n-amyl alcohol, using DBU as a catalyst under the 135 °C, molecular formula of phthalocyanine complexes is C38H16N8O12M. The product was characterized by Ultraviolet-visible (UV/Vis) Spectrum absorption and fluorescence, The results are agreement with the proposed structures. And electrochemical properties were studied. PMID:26672311

  6. Extinction law in the range 0.4 - 4.8 μm and the 8620 Å DIB towards the stellar cluster Westerlund 1

    NASA Astrophysics Data System (ADS)

    Damineli, A.; Almeida, L. A.; Blum, R. D.; Damineli, D. S. C.; Navarete, F.; Rubinho, M. S.; Teodoro, M.

    2016-08-01

    The young stellar cluster Westerlund 1 (Wd 1: l = 339.6°, b = -0.4°) is one of the most massive in the local Universe, but accurate parameters are pending on better determination of its extinction and distance. Based on our photometry and data collected from other sources, we have derived a reddening law for the cluster line-of-sight representative of the Galactic Plane (-5° < b <+5°) in the window 0.4-4.8 μm: The power law exponent α = 2.13±0.08 is much steeper than those published a decade ago (1.6-1.8) and our index RV = 2.50 ± 0.04 also differs from them, but in very good agreement with recent works based on deep surveys in the inner Galaxy. As a consequence, the total extinction AKs = 0.74±0.08 (AV = 11.40± 2.40) is substantially smaller than previous results(0.91-1.13), part of which (AKs = 0.63 or AV = 9.66) is from the ISM. The extinction in front of the cluster spans a range of ΔAV ˜8.7 with a gradient increasing from SW to NE across the cluster face, following the same general trend of warm dust distribution. The map of the J - Ks colour index also shows a trend of reddening in this direction. We measured the equivalent width of the diffuse interstellar band at 8620 Å (the "GAIA DIB") for Wd 1 cluster members and derived the relation AKs = 0.612 EW - 0.191 EW2. This extends the Munari et al. (2008) relation, valid for EB - V < 1, to the non-linear regime (AV > 4).

  7. Two novel Dy8 and Dy11 clusters with cubane [Dy4(μ3-OH)4]8+ units exhibiting slow magnetic relaxation behaviour.

    PubMed

    Miao, Yan-Li; Liu, Jun-Liang; Li, Jin-Yan; Leng, Ji-Dong; Ou, Yong-Cong; Tong, Ming-Liang

    2011-10-21

    Two unique octa- and hendeca-nuclear dysprosium(III) clusters incorporating [Dy(4)(μ(3)-OH)(4)](8+) cubane units have been synthesized with the 1,10-phenanthroline-2,9-dicarbaldehyde dioxime (H(2)phendox) ligand and DyCl(3)·6H(2)O or Dy(OAc)(3)·4H(2)O. They are [Dy(8)(OH)(8)(phendox)(6)(H(2)O)(8)]Cl(2)(OH)(2)·18H(2)O·18MeOH (1) and [Dy(11)(OH)(11)(phendox)(6)(phenda)(3)(OAc)(3)](OH)·40H(2)O·7MeOH (2). Adjacent Dy(8) in 1 or Dy(11) in 2 motifs are packed by off-set π-π interactions of the aromatic rings on phendox(2-) to generate a 3D supramolecular architecture in the honeycomb topology and with 1D or 3D channels along the c-axis. Adsorption research shows that complex 1 has selective adsorption ability for H(2)O over small gas molecules (H(2), N(2), CO(2)). Complex 2 is stable upon the removal of guest molecules and the desolvated compound absorbed a considerable amount of CO(2). Furthermore, the oximes underwent hydrolysis to carboxylic acid and the resulting 1,10-phenanthroline-2,9-dicarboxylate link the dysprosium atoms to form a hendecanuclear cluster of 2. Magnetic studies reveal that both clusters exhibit slow magnetic relaxation behavior, expanding upon the recent reports of the pure 4f type single-molecule magnets (SMMs). PMID:21894344

  8. 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

  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. PMID:23481818

  10. Search for 1-Hz Coronal-Loop Oscillations at the 2008 and 2009 Total Eclipses

    NASA Astrophysics Data System (ADS)

    Pasachoff, Jay M.; Babcock, B. A.; DuPré, K.; Kern, J.; Nesterenko, A.; Nesterenko, I.

    2010-05-01

    We report observations through narrow-band filters at total solar eclipses at high cadence to search for Fourier power 1 Hz, a prediction of certain classes of coronal heating through MHD waves, such as surface Alfvén waves. We previous reported such power at the 1999 eclipse (Pasachoff, Babcock, Russell, Seaton, Solar Phys. 207, 241-257, 2002). We observed at 10 Hz for 2 min 20 sec in Siberia in 2008 with the coronal red line at 637.4 nm and the coronal green line at 530.3 nm, and at 6 Hz for 5 min 50 sec at Tianhuangping, China, in 2009 with the coronal green line and a nearby continuum, using 20-cm telescopes. The sky was clear in 2008 while the eclipse was observed through moving clouds in 2009. The weakening corona gave few features on which to make a fine alignment, and much time has been spent on details of aligning the series of images. We report on the status of the alignment and the resulting transforms, and place the results in the context of the solar-activity cycle, which we show through a series of radial-filter images made as part of our expeditions in 1999, 2001, 2006, 2008, and 2009, spanning the most recent sunspot cycle. Acknowledgments: We thank C. Alex Young, Daniel B. Seaton. Yihua Yan, Jin Zhu, Lin Lan and Chenying Lai. Williams collaborators were Jianjun Wang, Marek Demianski, Huajai Cao, Sara Dwyer, and Rachel Wagner-Kaiser in 2009 and Marcus Freeman, William G. Wagner, and Marek Demianski in 2008. Our expeditions were supported in part by grants from the Committee for Research and Exploration of the National Geographic Society. We thank the NSF Heliospheric Program for 2006 suppport and the Planetary Astronomy division of NASA for imaging-system support.

  11. The distribution of kHz QPO frequencies in bright low mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Belloni, T.; Méndez, M.; Homan, J.

    2005-07-01

    We analyzed all published frequencies, ν1 and ν2, of the twin kilohertz quasi-periodic oscillations (kHz QPOs) in bright neutron star low-mass X-ray binaries. The two frequencies are well correlated but, contrary to recent suggestions, the frequency-frequency correlation is significantly different from a ν2 = (3/2) ν1 relation. To check whether, although not following the the 3/2 relation, the QPO frequencies cluster around a region where ν2/ν1 ≈ 3/2, we re-analyzed the Sco X-1 data that were used to report that ratio and show that, because the distribution of ratios of linearly correlated measurements is intrinsically biased, although the significance of the clustering around ν2/ν1 ≈ 3/2 previously reported in the case of Sco X-1 is formally correct, it does not provide any useful information about a possible underlying resonance mechanism in this source. Using the same data, we then show that the (unbiased) distribution of QPO frequencies is consistent with a uniform distribution at a 2.4σ level. To investigate this further, we analyzed a larger data set of Sco X-1 and four other sources, 4U 1608-52, 4U 1636-53, 4U 1728-34 and 4U 1820-30. We find that for all five sources the distribution of the kHz QPO frequencies is not uniform and has multiple peaks, which have no analogy in the distribution of points in the spectral color-color diagrams of these sources. Finally, we demonstrate that a simple random walk of the QPO frequencies can reproduce qualitatively the observed distributions in frequency and frequency ratio. This result weakens the support for resonance models of kHz QPOs in neutron stars.

  12. 2.5-kHz magnetostrictive Tonpilz sonar transducer design

    NASA Astrophysics Data System (ADS)

    Butler, Stephen C.

    2002-07-01

    Naval Undersea Warfare Center has fabricated and tested a 2.5 kHz magnetostrictive sonar transducer to validate various modeling techniques. The transducer selected is a longitudinal vibrator Tonpilz type consisting of Terfenol-D driver, tail mass, radiating head mass, and stress rod bolt with 21 MPa (3000 psi) prestress. The Terfenol-D drive rod is interlaced with three samarium cobalt magnets, one in the center and one on either end magnetically biasing the Terfenol to 60 kA/m (750 Oe). Both the Terfenol-D rods and magnets were laminated to reduce eddy currents. The magnetic circuit is comprised of pole piece discs on each end of the Terfenol-D magnet assembly and an external magnetic cylinder (return path) made of a high-permeability, high-resistivity, high-saturation powdered metal 'T2'. The transducer has a 25 cm (9.8in) diameter radiating face (piston), is 28 cm (11 in.) long, and weighs 15 kg (32 lb.) without the housing. It is 41 cm (16 in.) long and 25 kg (56 lb.) with the underwater housing. The measured results are compared to a finite element model using 'ATILA' and distributed plane wave element equivalent circuit model. The coupling coefficient, permeability and mechanical loss effects for different prestress loads were measured on a resonant Terfenol 'dumbbell' device. The in-water measured results indicate a mechanical Q of 2.5, an effective coupling coefficient of 0.36, an electro-acoustic efficiency of 60 percent, beam pattern directivity index of 6 dB, a maximum Source Level of 214.6 dB re 1uPa/m at 15 Amps AC drive and bandwidth of 2 kHz to 5.4 kHz +/- 1.5 dB.

  13. 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.

  14. 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.

  15. Assessment of "non-recordable" electroretinograms by 9 Hz flicker stimulation under scotopic conditions.

    PubMed

    Schatz, Andreas; Wilke, Robert; Strasser, Torsten; Gekeler, Florian; Messias, Andre; Zrenner, Eberhart

    2012-02-01

    To refine methods of electroretinographical (ERG) recording for the analysis of low retinal potentials under scotopic conditions in advanced retinal degenerative diseases. Standard Ganzfeld ERG equipment (Diagnosys LLC, Cambridge, UK) was used in 27 healthy volunteers (mean age 28 ± SD 8.5 years) to define the stimulation protocol. The protocol was then applied in clinical routine and 992 recordings were obtained from patients (mean age 40.6 ± 18.3 years) over a period of 5 years. A blue stimulus with a flicker frequency of 9 Hz was specified under scotopic conditions to preferentially record rod-driven responses. A range of stimulus strengths (0.0000012-6.32 scot. cd s/m² and 6-14 ms flash duration) was tested for maximal amplitudes and interference between rods and cones. Analysis of results was done by standard Fourier Transformation and assessment of signal-to-noise ratio. Optimized stimulus parameters were found to be a time-integrated luminance of 0.012 scot. cd s/m² using a blue (470 nm) flash of 10 ms duration at a repetition frequency of 9 Hz. Characteristic stimulus strength versus amplitude curves and tests with stimuli of red or green wavelength suggest a predominant rod-system response. The 9 Hz response was found statistically distinguishable from noise in 38% of patients with otherwise non-recordable rod responses according to International Society for Clinical Electrophysiology of Vision standards. Thus, we believe this protocol can be used to record ERG potentials in patients with advanced retinal diseases and in the evaluation of potential treatments for these patients. The ease of implementation in clinical routine and of statistical evaluation providing an observer-independent evaluation may further facilitate its employment. PMID:22179598

  16. Lack of Teratological Effects in Rats Exposed to 20 or 60 kHz Magnetic Fields

    PubMed Central

    Nishimura, Izumi; Oshima, Atsushi; Shibuya, Kazumoto; Negishi, Tadashi

    2011-01-01

    BACKGROUND: A risk assessment of magnetic field (MF) exposure conducted by the World Health Organization indicated the need for biological studies on primary hazard identification and quantitative risk evaluation of intermediate frequency (300 Hz–100 kHz) MFs. Because induction heating cookers generate such MFs for cooking, reproductive and developmental effects are a concern due to the close proximity of the fields' source to a cook's abdomen. METHODS: Pregnant Crl:CD(SD) rats (25/group) were exposed to a 20 kHz, 0.2 mT(rms) or 60 kHz, 0.1 mT(rms) sinusoidal MF or sham-exposed for 22 hr/day during organogenesis, and their fetuses were examined for malformations on gestation day 20. All teratological evaluations were conducted in a blind fashion, and experiments were duplicated for each frequency to confirm consistency of experimental outcomes. RESULTS: No exposure-related changes were found in clinical signs, gross pathology, or number of implantation losses. The number of live fetuses and low-body-weight fetuses as well as the incidence of external, visceral, and skeletal malformations in the fetuses did not indicate significant differences between MF-exposed and sham-exposed groups. Although some fetuses showed isolated changes in sex ratio and skeletal variation and ossification, such changes were neither reproduced in duplicate experiments nor were they common to specific field frequencies. CONCLUSIONS: Exposure of rats to MFs during organogenesis did not show significant reproducible teratogenicity under experimental conditions. Present findings do not support the hypothesis that intermediate frequency MF exposure after implantation carries a significant risk for developing mammalian fetuses. Birth Defects Res (Part B) 92:469–477, 2011. © 2011 Wiley Periodicals, Inc. PMID:21770026

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. Variation of 40 kHz Signal Level in Relation to Sunrise, Sunset and Climatic Condition

    NASA Astrophysics Data System (ADS)

    Guha, A.; De, B. K.; Saha, A.; Das, T. K.

    2007-07-01

    The sunrise effect, sunset effect, the diurnal and seasonal variations are the characteristic feature of low frequency (LF) radio wave propagated over a large distance. The normal character has been found to be perturbed during rainy days. The amplitude of 40 kHz signal transmitted from Miyakoji station, Japan and received in North-East India is remarkably attenuated after the commencement of rain. On the basis of nature of attenuation the observed records have been classified into two different forms viz., F1 and F2. An analysis in this regard is represented in this paper.

  2. 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.

  3. 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.

  4. In situ 24 kHz coherent imaging of morphology change in laser percussion drilling.

    PubMed

    Webster, Paul J L; Yu, Joe X Z; Leung, Ben Y C; Anderson, Mitchell D; Yang, Victor X D; Fraser, James M

    2010-03-01

    We observe sample morphology changes in real time (24 kHz) during and between percussion drilling pulses by integrating a low-coherence microscope into a laser micromachining platform. Nonuniform cut speed and sidewall evolution in stainless steel are observed to strongly depend on assist gas. Interpulse morphology relaxation such as hole refill is directly imaged, showing dramatic differences in the material removal process dependent on pulse duration/peak power (micros/0.1 kW, ps/20 MW) and material (steel, lead zirconate titanate PZT). Blind hole depth precision is improved by over 1 order of magnitude using in situ feedback from the imaging system. PMID:20195306

  5. 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

  6. 340-GHz 3D radar imaging test bed with 10-Hz frame rate

    NASA Astrophysics Data System (ADS)

    Robertson, Duncan A.; Marsh, Paul N.; Bolton, David R.; Middleton, Robert J. C.; Hunter, Robert I.; Speirs, Peter J.; Macfarlane, David G.; Cassidy, Scott L.; Smith, Graham M.

    2012-06-01

    We present a 340 GHz 3D radar imaging test bed with 10 Hz frame rate which enables the investigation of strategies for the detection of concealed threats in high risk public areas. The radar uses a wideband heterodyne scheme and fast-scanning optics to achieve moderate resolution volumetric data sets, over a limited field of view, of targets at moderate stand-off ranges. The high frame rate is achieved through the use of DDS chirp generation, fast galvanometer scanners and efficient processing which combines CPU multi-threading and GPU-based techniques, and is sufficiently fast to follow smoothly the natural motion of people.

  7. 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.

  8. 8-kHz bottom backscattering measurements at low grazing angles in shallow water.

    PubMed

    La, Hyoungsul; Choi, Jee Woong

    2010-04-01

    8-kHz bottom backscattering measurements at low grazing angles (6 degrees -31 degrees ) are presented. The experiment was performed at a very shallow water site with a silty bottom on the south coast of Korea. Backscattering strengths between -42 and -30 dB were obtained and were compared to a theoretical backscattering model and Lambert's law. The fit of the theoretical model to the measurements suggests that sediment volume scattering is dominant over scattering from bottom interface roughness. Combining these results with previous measurements found in the published literature implies that backscattering strengths from silty sediment increase slightly as the frequency increases. PMID:20369984

  9. 200 Deg C Demonstration Transformer Operates Efficiently at 50 kHz

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.; Schwarze, Gene E. (Technical Monitor)

    2003-01-01

    A compact, high temperature demonstration transformer was constructed, using a moly permalloy powder core and Teflon -insulated copper wire. At 50 kHz and 200 C, this 1:2 ratio transformer is capable of 98 percent efficiency when operating at a specific power of 6.1 kW/kg at 4 kW. This roughly 7 cm diameter transformer has a mass of 0.65 kg. Although Teflon is unstable above 200 C, about the same electrical performance was seen at 250 C. A plot of winding loss versus frequency illustrates the need to control these losses at high frequency.

  10. Complete synthetic seismograms up to 2 Hz for transversely isotropic spherically symmetric media

    NASA Astrophysics Data System (ADS)

    Kawai, Kenji; Takeuchi, Nozomu; Geller, Robert J.

    2006-02-01

    We use the direct solution method (DSM) with optimally accurate numerical operators to calculate complete (including both body and surface waves) three-component synthetic seismograms for transversely isotropic (TI), spherically symmetric media, up to 2 Hz. We present examples of calculations for both deep (600 km) and shallow (5 km) sources. Such synthetics should be useful in forward and inverse studies of earth structure. In order to make these calculations accurately and efficiently the vertical grid spacing, maximum angular order, and cut-off depth must be carefully and systematically chosen.

  11. 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.

  12. 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.

  13. A 5 Hz flashlamp pumped Cr:LiSAF multipass amplifier for ultrashort pulses

    NASA Astrophysics Data System (ADS)

    Samad, R. E.; Nogueira, G. E. C.; Baldochi, S. L.; Vieira, N. D., Jr.

    2008-10-01

    We report here the operation, at 5 Hz, of a multipass flashlamp pumped Cr:LiSAF ultrashort pulse amplifier, presenting peak powers over 0.3 TW. This unusual high repetition rate was obtained by using a two-flashlamp pumping scheme, aiming at the minimization of the thermal load on the gain medium by the use of intracavity absorption filters. This cavity was used as a four-pass multipass amplifier in a hybrid Ti:sapphire/Cr:LiSAF system. The maximum amplification factor was 150, and the compressed pulse duration was 60 fs.

  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. Infrared peak in HZ Herculis prior to X-ray eclipse

    SciTech Connect

    Gnedin, IU.N.; Kirian, V.V.; Krat, A.V.; Pogodin, M.A.; Tarasov, A.E.

    1986-04-01

    In the summer and autumn of 1984, HZ Her (one of the stars in the Hercules X-1 binary system) was observed in the IR (J, H, and K bands) with the 125-cm AZT-11 telescope of the Crimean Astrophysical Observatory. The observations of the star disclosed a sharp IR peak at orbital phase phi = 0.91, shortly before an X-ray eclipse, reaching a power greater than about 10 to the 36th erg/s. Although several hypotheses are suggested to provide an interpretation of this phenomenon, none of the proposed mechanisms can fully explain the peculiarities in the object's light curves close to eclipse. 16 references.

  16. 1047nm 270mJ all solid state diode pumped MOPA at 50 Hz

    NASA Astrophysics Data System (ADS)

    Ma, Jian; Yang, Qi; Lu, Tingting; Ma, Xiuhua; Zhu, Xiaolei; Chen, Weibiao

    2015-02-01

    A diode-pumped nanosecond Master Oscillator Power Amplifier (MOPA) system based on Nd:YLF crystal slabs has been demonstrated. The seed pulses with pulse duration of 11 ns were generated in an EO Q-switched Nd:YLF laser, with single pulse energy of 10 mJ. The 1047 nm signal pulses were amplified in a double-pass amplification system. Maximum output pulse energy of 270 mJ at a repetition rate of 50 Hz has been achieved with effective optical-to-optical efficiency of 14.5%.

  17. 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. PMID:22423727

  18. Alcoholism, Alpha Production, and Biofeedback

    ERIC Educational Resources Information Center

    Jones, Frances W.; Holmes, David S.

    1976-01-01

    Electroencephalograms of 20 alcoholics and 20 nonalcoholics were obtained. Data indicated that alcoholics produced less alpha than nonalcoholics. In one training condition subjects were given accurate biofeedback, whereas in the other condition subjects were given random (noncontingent) feedback. Accurate biofeedback did not result in greater…

  19. Alpha proton x ray spectrometer

    NASA Technical Reports Server (NTRS)

    Rieder, Rudi; Waeke, H.; Economou, T.

    1994-01-01

    Mars Pathfinder will carry an alpha-proton x ray spectrometer (APX) for the determination of the elemental chemical composition of Martian rocks and soils. The instrument will measure the concentration of all major and some minor elements, including C, N, and O at levels above typically 1 percent.

  20. Meet the Alpha-Pets.

    ERIC Educational Resources Information Center

    Zitlaw, Jo Ann Bruce; Frank, Cheryl Standish

    1985-01-01

    "Alpha-Pets" are the focal point of an integrated, multidisciplinary curriculum. Each pet is featured for a week in a vocabulary-rich story and introduces related activities beginning with the featured letter, such as the four food groups during Freddie Fish's week or universe during Ulysses Unicorn's week. (MT)

  1. Sparse Coding for Alpha Matting

    NASA Astrophysics Data System (ADS)

    Johnson, Jubin; Varnousfaderani, Ehsan Shahrian; Cholakkal, Hisham; Rajan, Deepu

    2016-07-01

    Existing color sampling based alpha matting methods use the compositing equation to estimate alpha at a pixel from pairs of foreground (F) and background (B) samples. The quality of the matte depends on the selected (F,B) pairs. In this paper, the matting problem is reinterpreted as a sparse coding of pixel features, wherein the sum of the codes gives the estimate of the alpha matte from a set of unpaired F and B samples. A non-parametric probabilistic segmentation provides a certainty measure on the pixel belonging to foreground or background, based on which a dictionary is formed for use in sparse coding. By removing the restriction to conform to (F,B) pairs, this method allows for better alpha estimation from multiple F and B samples. The same framework is extended to videos, where the requirement of temporal coherence is handled effectively. Here, the dictionary is formed by samples from multiple frames. A multi-frame graph model, as opposed to a single image as for image matting, is proposed that can be solved efficiently in closed form. Quantitative and qualitative evaluations on a benchmark dataset are provided to show that the proposed method outperforms current state-of-the-art in image and video matting.

  2. Alpha Testing Escape from Diab

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alpha testing was conducted of sessions 2 and 3 from Diab to assess whether the activities worked as expected, and whether children in the target ages enjoyed it. Data include both RA observations of child performance while playing the games and cognitive interview responses from the players after t...

  3. Regional electroencephalogram (EEG) alpha power and asymmetry in older adults: a study of short-term test–retest reliability

    PubMed Central

    Mathewson, Karen J.; Hashemi, Ali; Sheng, Bruce; Sekuler, Allison B.; Bennett, Patrick J.; Schmidt, Louis A.

    2015-01-01

    Although regional alpha power and asymmetry measures have been widely used as indices of individual differences in emotional processing and affective style in younger populations, there have been relatively few studies that have examined these measures in older adults. Here, we examined the short-term test–retest reliability of resting regional alpha power (7.5–12.5 Hz) and asymmetry in a sample of 38 active, community-dwelling older adults (M age = 71.2, SD = 6.5 years). Resting electroencephalogram recordings were made before and after a perceptual computer task. Pearson and intra-class correlations indicated acceptable test–retest reliability for alpha power and asymmetry measures in all regions. Interestingly, alpha asymmetry appeared to be less affected by the task than was alpha power. Findings suggest that alpha asymmetry may reflect more enduring, “trait-like” characteristics, while alpha power may reflect more “state-like” processes in older adults. PMID:26441639

  4. 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

  5. Pulsed Out of Awareness: EEG Alpha Oscillations Represent a Pulsed-Inhibition of Ongoing Cortical Processing

    PubMed Central

    Mathewson, Kyle E.; Lleras, Alejandro; Beck, Diane M.; Fabiani, Monica; Ro, Tony; Gratton, Gabriele

    2011-01-01

    Alpha oscillations are ubiquitous in the brain, but their role in cortical processing remains a matter of debate. Recently, evidence has begun to accumulate in support of a role for alpha oscillations in attention selection and control. Here we first review evidence that 8–12 Hz oscillations in the brain have a general inhibitory role in cognitive processing, with an emphasis on their role in visual processing. Then, we summarize the evidence in support of our recent proposal that alpha represents a pulsed-inhibition of ongoing neural activity. The phase of the ongoing electroencephalography can influence evoked activity and subsequent processing, and we propose that alpha exerts its inhibitory role through alternating microstates of inhibition and excitation. Finally, we discuss evidence that this pulsed-inhibition can be entrained to rhythmic stimuli in the environment, such that preferential processing occurs for stimuli at predictable moments. The entrainment of preferential phase may provide a mechanism for temporal attention in the brain. This pulsed inhibitory account of alpha has important implications for many common cognitive phenomena, such as the attentional blink, and seems to indicate that our visual experience may at least some times be coming through in waves. PMID:21779257

  6. Determination of human EEG alpha entrainment ERD/ERS using the continuous complex wavelet transform

    NASA Astrophysics Data System (ADS)

    Chorlian, David B.; Porjesz, Bernice; Begleiter, Henri

    2003-04-01

    Alpha entrainment caused by exposure to a background stimulus continuously flickering at a rate of 8 1/3 Hz was affected by the appearance of a foreground target stimulus to which the subjects were requested to press a button. With the use of bipolar derivations (to reduce volume conduction effects), scalp recorded EEG potentials were subjected to a continuous wavelet transform using complex Morlet wavelets at a range of scales. Complex Morlet wavelets were used to calculate efficiently instantaneous amplitudes and phases on a per-trial basis, rather than using the Hilbert transform on band-pass filtered data. Multiple scales were employed to contrast the pattern of alpha activity with those in other bands, and to determine whether the harmonics observed in the spectral analysis of the data were simply a result of the non-sinusoidal response to the entraining signal or a distinct neural phenomenon. We were thus able to calculate desynchronization/resynchronization for both the entrained and non-entrained alpha activity. The occurance of the target stimulus caused a sharp increase in amplitude in both the entrained and non-entrained alpha activity, followed by a sharp decrease, and then a return to baseline, over a period of 2.5 seconds. However, the entrained alpha activity showed a much more rapid recovery than non-entrained activity.

  7. Modulation of gene expression by alpha-tocopherol and alpha-tocopheryl phosphate in thp-1 monocytes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The naturally occurring vitamin E analogue, alpha-tocopheryl phosphate (alphaTP), has been reported to be more potent than the un-phosphorylated alpha alpha-tocopherol (alphaT). We have now measured plasma levels of alphaTP and compared the cellular effects of alphaTP and gamma-tocopheryl phosphate ...

  8. Endotoxin enhances EEG alpha and beta power in human sleep.

    PubMed

    Trachsel, L; Schreiber, W; Holsboer, F; Pollmächer, T

    1994-03-01

    Endotoxin, a lipopolysaccharide (0.4 or 0.8 ng/kg body weight), was injected at 1900 hours in 17 healthy men in a single-blind, placebo-controlled experiment. The administration was followed by a 4-hour period of quiet wakefulness in bed (light intensity < 200 lux). Unlimited sleep was allowed after 2300 hours (lights off) until the next morning. The electroencephalogram (EEG), electromyogram, electrooculogram, electrocardiogram and rectal temperature were recorded throughout the experimental session. Standard sleep stages were assessed, and the EEG was submitted to a state-specific, serial spectral analysis. Endotoxin administration induced a rise of body temperature and heart rate, which started approximately 2 hours after the injection and persisted through most of the sleep period. Sleep latency remained unchanged, whereas rapid eye movement (REM) sleep latency increased from 60.3 to 89.0 minutes (paired t test; p = 0.06) compared to control values. Stage 2 sleep was elevated from 45.5 to 49.0% of time in bed (p < 0.05), and total nonrapid eye movement (NREM) sleep from 64.2 to 69.1% (p < 0.05). No significant change could be observed in slow-wave sleep (SWS, stages 3 and 4). During the first 4 hours of the sleep period, NREM sleep EEG spectral power was distinctly and markedly increased between 8 and 12 Hz (alpha) and 15 and 20 Hz (beta) (p < 0.05), whereas at the same time EEG power between 1 and 8 Hz (delta, theta) was not significantly changed. We conclude that in humans the primary host response induced by endotoxin initially suppresses REM sleep and increases stage 2 NREM sleep, but does not affect SWS. No clear modification of sleep EEG delta activity could be observed after endotoxin injection, despite marked endocrinological and physiological changes such as the elevation of body temperature. Numerous factors related to the human primary host response may be responsible for the EEG intensification of the alpha and beta range. PMID:8036367

  9. Coexistence of {alpha}+{alpha}+n+n and {alpha}+t+t cluster structures in {sup 10}Be

    SciTech Connect

    Itagaki, N.; Ito, M.; Milin, M.; Hashimoto, T.; Ishiyama, H.; Miyatake, H.

    2008-06-15

    The coexistence of the {alpha}+{alpha}+n+n and {alpha}+t+t cluster structures in the excited states of {sup 10}Be has been discussed. In the previous analysis, all the low-lying states of {sup 10}Be were found to be well described by the motion of the two valence neutrons around two {alpha} clusters. However, the {alpha}+t+t cluster structure was found to coexist with the {alpha}+{alpha}+n+n structure around E{sub x}=15 MeV, close to the corresponding threshold. We have introduced a microscopic model to solve the coupling effect between these two configurations. The K=0 and K=1 states are generated from the {alpha}+t+t configurations due to the spin coupling of two triton clusters. The present case of {sup 10}Be is one of the few examples in which completely different configurations of triton-type ({alpha}+t+t three-center) and {alpha}-type ({alpha}+{alpha}+n+n two-center) clusters coexist in a single nucleus in the same energy region.

  10. [Slow alpha in the EEG power spectrum as an indicator for conceptual arousal].

    PubMed

    Bösel, R

    1992-01-01

    Based on previous findings (Bösel et al., 1990) it was assumed that in concept learning tasks generating on hypotheses on a concept which has to be developed is accompanied by increases of the Alpha 1 power (7.5-10 Hz) in the spontaneous EEG activity. In this study 16 subjects performed five problem solving tasks with similar processing requirements. EEG data were analyzed by means of post hoc comparisons of subjects differing in performance quality. Additionally, four control tasks were employed in which, based on previous studies, variations in the Theta frequency range were expected. An effect in the Alpha 1 frequency band was observed in tasks requiring reconstructive recall or testing the usefulness of an mathematical algorithm. The creation of a rank order or mental map is accompanied by power increases in the lower portions of the Alpha 1 frequency band (7.5-8.5 Hz). Moreover a high amount of controlled variance (eta2 up to 34%) was obtained for this effect. Increases in EEG Theta power, which presumably indicate subjects' component analysis, were found before the subjects recognized parts of geometric figures or before relevant features in the "buddhist monk problem" were discriminated. The dynamics of EEG power over time is in examples of frequency/time plots in a figure, illustrated. PMID:1441650

  11. Attention Drives Synchronization of Alpha and Beta Rhythms between Right Inferior Frontal and Primary Sensory Neocortex

    PubMed Central

    Sacchet, Matthew D.; LaPlante, Roan A.; Wan, Qian; Pritchett, Dominique L.; Lee, Adrian K.C.; Hämäläinen, Matti; Moore, Christopher I.; Kerr, Catherine E.

    2015-01-01

    The right inferior frontal cortex (rIFC) is specifically associated with attentional control via the inhibition of behaviorally irrelevant stimuli and motor responses. Similarly, recent evidence has shown that alpha (7–14 Hz) and beta (15–29 Hz) oscillations in primary sensory neocortical areas are enhanced in the representation of non-attended stimuli, leading to the hypothesis that allocation of these rhythms plays an active role in optimal inattention. Here, we tested the hypothesis that selective synchronization between rIFC and primary sensory neocortex occurs in these frequency bands during inattention. We used magnetoencephalography to investigate phase synchrony between primary somatosensory (SI) and rIFC regions during a cued-attention tactile detection task that required suppression of response to uncertain distractor stimuli. Attentional modulation of synchrony between SI and rIFC was found in both the alpha and beta frequency bands. This synchrony manifested as an increase in the alpha-band early after cue between non-attended SI representations and rIFC, and as a subsequent increase in beta-band synchrony closer to stimulus processing. Differences in phase synchrony were not found in several proximal control regions. These results are the first to reveal distinct interactions between primary sensory cortex and rIFC in humans and suggest that synchrony between rIFC and primary sensory representations plays a role in the inhibition of irrelevant sensory stimuli and motor responses. PMID:25653364

  12. Binaural beats increase interhemispheric alpha-band coherence between auditory cortices.

    PubMed

    Solcà, Marco; Mottaz, Anaïs; Guggisberg, Adrian G

    2016-02-01

    Binaural beats (BBs) are an auditory illusion occurring when two tones of slightly different frequency are presented separately to each ear. BBs have been suggested to alter physiological and cognitive processes through synchronization of the brain hemispheres. To test this, we recorded electroencephalograms (EEG) at rest and while participants listened to BBs or a monaural control condition during which both tones were presented to both ears. We calculated for each condition the interhemispheric coherence, which expressed the synchrony between neural oscillations of both hemispheres. Compared to monaural beats and resting state, BBs enhanced interhemispheric coherence between the auditory cortices. Beat frequencies in the alpha (10 Hz) and theta (4 Hz) frequency range both increased interhemispheric coherence selectively at alpha frequencies. In a second experiment, we evaluated whether this coherence increase has a behavioral aftereffect on binaural listening. No effects were observed in a dichotic digit task performed immediately after BBs presentation. Our results suggest that BBs enhance alpha-band oscillation synchrony between the auditory cortices during auditory stimulation. This effect seems to reflect binaural integration rather than entrainment. PMID:26541421

  13. 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

  14. Dual contractile effects of ATP released by field stimulation revealed by effects of alpha,beta-methylene ATP and suramin in rat tail artery.

    PubMed Central

    Bao, J. X.; Stjärne, L.

    1993-01-01

    1. The field stimulation-induced release of endogenous ATP and noradrenaline (NA) and contractile response in rat isolated tail artery were examined. The release of ATP was studied by extracellular electrophysiological recording and that of NA by a novel voltammetrical technique. The effects of the P2-purinceptor antagonist, suramin, on these parameters were compared with those of alpha,beta-methylene ATP, a P2X-purinoceptor desensitizing agent. 2. Neither alpha,beta-methylene ATP (10 microM) nor suramin (100-500 microM) had significant effects on the extracellularly recorded nerve terminal action potential but both abolished the ATP-induced excitatory junction current caused by stimulation at 0.1 Hz. Neither agent affected significantly the voltammetrically measured release of NA induced by 10 or 100 pulses at 20 Hz. 3. Combined blockade of both postjunctional alpha 1- and alpha 2-adrenoceptors by prazosin and yohimbine (both 0.1 microM) profoundly depressed the contractile response to 10 pulses at 20 Hz. The small and fast residual contraction in the presence of these agents was abolished by alpha,beta-methylene ATP (10 microM) and inhibited by suramin in a concentration-dependent manner (10-500 microM; IC50 75 microM) and was hence probably caused by ATP or a related nucleotide. 4. When added first, alpha,beta-methylene ATP (10 microM) or suramin (100-500 microM) delayed the onset and enhanced the amplitude of the neurogenic contraction. This enhanced response was abolished by further addition of prazosin and yohimbine (both 0.1 microM). 5. The K+ channel blocker, tetraethylammonium (10 mM), dramatically enhanced the contractile response to 100 pulses at 1 Hz and caused it to become diphasic.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8306081

  15. The effect of multidrug resistance modulator HZ08 on pharmacodynamics and pharmacokinetics of adriamycin in xenograft-nude mice.

    PubMed

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

    2015-01-23

    To overcome MDR (multidrug resistance) of cancer mediated by P-gp (P-glycoprotein) has become a key strategy to improve the survival rate in clinic. Therefore, it is imperative to develop advanced modulators that have no side effects or interactions with cytotoxic drugs. HZ08, which acts as a P-gp inhibitor, shows a notable reverse effect with low cytotoxicity in vitro. Based on the previous results, the goal of this experiment is to elucidate the effect of HZ08 on pharmacodynamics and pharmacokinetics of adriamycin in tumor-bearing nude mice. Several criterions and methods, such as tumor weight and volume, in vivo imaging, western blot, immunohistochemistry as well as ATPase hydrolysis assay were selected to evaluate the reversing activity and mechanism of HZ08 on MDR; Furthermore, fluorescence detection assay was applied to determine the distribution of adriamycin in the blood and tissues. This study revealed that HZ08 potentiated the anti-tumor activity of adriamycin but with little effect on the expression of P-gp in vivo. Adriamycin accumulation in tumor was enhanced by HZ08 via ATPase activity inhibition. In addition, HZ08 did not alter the pharmacokinetic characteristic of adriamycin in plasma or tissues. In conclusion, HZ08 showed dramatic MDR reversing activity and had no influence on the pharmacokinetics of adriamycin. PMID:25459530

  16. Posterior EEG alpha at rest and during task performance: Comparison of current source density and field potential measures

    PubMed Central

    Tenke, Craig E.; Kayser, Jürgen; Abraham, Karen; Alvarenga, Jorge E.; Bruder, Gerard E.

    2015-01-01

    Resting and task-related EEG alpha are used in studies of cognition and psychopathogy. Although Laplacian methods have been applied, apprehensions about loss of global activity dissuade researchers from greater use except as a supplement to reference-dependent measures. The unfortunate result has been continued reliance on reference strategies that differ across labs, and a systemic preference for a montage-dependent average reference over true reference-free measures. We addressed these concerns by comparing resting- and task-related EEG alpha using three EEG transformations: nose- (NR) and average-referenced (AR) EEG, and the corresponding CSD. Amplitude spectra of resting and prestimulus task-related EEG (novelty oddball) and event-related spectral perturbations were scaled to equate each transformation. Alpha measures quantified for 8-12 Hz bands were: 1) net amplitude (eyes-closed minus eyes-open) and 2) overall amplitude (eyes-closed plus eyes-open); 3) task amplitude (prestimulus baseline) and 4) task event-related desynchronization (ERD). Mean topographies unambiguously represented posterior alpha for overall, net and task, as well as poststimulus alpha ERD. Topographies were similar for the three transformations, but differed in dispersion, CSD being sharpest and NR most broadly distributed. Transformations also differed in scale, AR showing less attenuation or spurious secondary maxima at anterior sites, consistent with simulations of distributed posterior generators. Posterior task alpha and alpha ERD were positively correlated with overall alpha, but not with net alpha. CSD topographies consistently and appropriately represented posterior EEG alpha for all measures. PMID:26026372

  17. 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.

  18. 35 Hz shape memory alloy actuator with bending-twisting mode

    NASA Astrophysics Data System (ADS)

    Song, Sung-Hyuk; Lee, Jang-Yeob; Rodrigue, Hugo; Choi, Ik-Seong; Kang, Yeon June; Ahn, Sung-Hoon

    2016-02-01

    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.

  19. 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

  20. 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