Science.gov

Sample records for 400s sampo em-soundings

  1. The development of an instrumented tamp-filling capsule machine I. Instrumentation Of a Bosch GKF 400S machine and feasibility study.

    PubMed

    Podczeck, F

    2000-01-01

    The instrumentation of capsule filling machines operating by the tamp-filling principle has been described only once, using strain gauges. In the present paper the instrumentation of a Bosch GKF 400S tamp-filling machine has been described using a prototype of a pneumatic tamping head equipped with a piezoelectric force transducer. The pneumatic system replaces the conventional springs situated between tamping pins and upper part of the tamping head. Via a feedback switch valve, the air pressure inside the pneumatic chamber can be regulated. This provides a potential mechanism for feedback control of capsule fill weight during continuous capsule filling. It was found that the use of the pneumatic tamping head is limited to the control of fill weight during tamping. Major adjustments of fill weight at the set-up stage of the machine should be made by alteration of the tamping pin and powder bed height settings. The principles of capsule fill weight control by continuous monitoring of tamping forces have been established, but the transfer of the system to full industrial use requires further development of the prototype by the machine manufacturer. PMID:10838016

  2. Parafoveal versus foveal N400s dissociate spreading activation from contextual fit.

    PubMed

    Kretzschmar, Franziska; Bornkessel-Schlesewsky, Ina; Schlesewsky, Matthias

    2009-12-01

    Using concurrent electroencephalogram and eye movement measures to track natural reading, this study shows that N400 effects reflecting predictability are dissociable from those owing to spreading activation. In comparing predicted sentence endings with related and unrelated unpredicted endings in antonym constructions ('the opposite of black is white/yellow/nice'), fixation-related potentials at the critical word revealed a predictability-based N400 effect (unpredicted vs. predicted words). By contrast, event-related potentials time locked to the last fixation before the critical word showed an N400 only for the nonrelated unpredicted condition (nice). This effect is attributed to a parafoveal mismatch between the critical word and preactivated lexical features (i.e. features of the predicted word and its associates). In addition to providing the first demonstration of a parafoveally induced N400 effect, our results support the view that the N400 is best viewed as a component family.

  3. Gamma-Ray Spectrum Analysis Method for Minicomputers.

    1984-01-24

    Version 00 SAMPO80 is a rapid and accurate analysis program for gamma-ray spectra measured with Ge(Li) or HPGe detectors. SAMPO80 consists of three separate parts, the shape calibration part SAMPOSHAPE, the peak search and fitting part SAMPOFIT, and the nuclide identification part SAMPOID.

  4. Next-generation electromagnetic sounding of the Moon

    NASA Astrophysics Data System (ADS)

    Grimm, Robert E.; Delory, Gregory T.

    2012-12-01

    Electromagnetic (EM) sounding of the Moon, largely performed during the Apollo program, provided constraints on core size, mantle composition, and interior temperature. We present new analytical and numerical models that demonstrate the abilities of a next generation of EM sounding to (1) determine the electrical structure of the outermost 500 km and its lateral variability, specifically to understand the extent of upper-mantle discontinuities and the structure of the Procellarum KREEP Terrane; (2) determine the temperature and composition of the lower mantle; and (3) better constrain core size. New EM sounding need not rely on the Apollo methodology, which analyzed the magnetic transfer function between a surface station and a distantly orbiting satellite. Instead, a network of magnetometers (as few as two) can be used, or a complete sounding can be performed from a single station by measuring both electric and magnetic fields. Furthermore, in the magnetotail or lunar wake, sensors can operate from orbit, at altitudes up to the desired investigation depth. The twin-spacecraft ARTEMIS mission will test these methods and a lunar geophysical network will provide definitive results.

  5. ESO Reflex: A Graphical Workflow Engine for Astronomical Data Reduction

    NASA Astrophysics Data System (ADS)

    Hook, Richard; Romaniello, Martino; Ullgrén, Marko; Maisala, Sami; Solin, Otto; Oittinen, Tero; Savolainen, Villa; Järveläinen, Pekka; Tyynelä, Jani; Péron, Michèle; Izzo, Carlo; Ballester, Pascal; Gabasch, Armin

    2008-03-01

    ESO Reflex is a software tool that provides a novel approach to astronomical data reduction. The reduction sequence is rendered and controlled as a graphical workflow. Users can follow and interact with the processing in an intuitive manner, without the need for complex scripting. The graphical interface also allows the modification of existing workflows and the creation of new ones. ESO Reflex can invoke standard ESO data reduction recipes in a flexible way. Python scripts, IDL procedures and shell commands can also be easily brought into workflows and a variety of visualisation and display options, including custom product inspection and validation steps, are available. ESO Reflex was developed in the context of the Sampo project, a three-year effort led by ESO and conducted by a software development team from Finland as an in-kind contribution to joining ESO. It is planned that the software will be released to the community in late 2008.

  6. ESO Reflex: a graphical workflow engine for data reduction

    NASA Astrophysics Data System (ADS)

    Hook, Richard; Ullgrén, Marko; Romaniello, Martino; Maisala, Sami; Oittinen, Tero; Solin, Otto; Savolainen, Ville; Järveläinen, Pekka; Tyynelä, Jani; Péron, Michèle; Ballester, Pascal; Gabasch, Armin; Izzo, Carlo

    ESO Reflex is a prototype software tool that provides a novel approach to astronomical data reduction by integrating a modern graphical workflow system (Taverna) with existing legacy data reduction algorithms. Most of the raw data produced by instruments at the ESO Very Large Telescope (VLT) in Chile are reduced using recipes. These are compiled C applications following an ESO standard and utilising routines provided by the Common Pipeline Library (CPL). Currently these are run in batch mode as part of the data flow system to generate the input to the ESO/VLT quality control process and are also exported for use offline. ESO Reflex can invoke CPL-based recipes in a flexible way through a general purpose graphical interface. ESO Reflex is based on the Taverna system that was originally developed within the UK life-sciences community. Workflows have been created so far for three VLT/VLTI instruments, and the GUI allows the user to make changes to these or create workflows of their own. Python scripts or IDL procedures can be easily brought into workflows and a variety of visualisation and display options, including custom product inspection and validation steps, are available. Taverna is intended for use with web services and experiments using ESO Reflex to access Virtual Observatory web services have been successfully performed. ESO Reflex is the main product developed by Sampo, a project led by ESO and conducted by a software development team from Finland as an in-kind contribution to joining ESO. The goal was to look into the needs of the ESO community in the area of data reduction environments and to create pilot software products that illustrate critical steps along the road to a new system. Sampo concluded early in 2008. This contribution will describe ESO Reflex and show several examples of its use both locally and using Virtual Observatory remote web services. ESO Reflex is expected to be released to the community in early 2009.

  7. In silico analysis of gene expression profiles in the olfactory mucosae of aging senescence-accelerated mice.

    PubMed

    Getchell, Thomas V; Peng, Xuejun; Green, C Paul; Stromberg, Arnold J; Chen, Kuey-Chu; Mattson, Mark P; Getchell, Marilyn L

    2004-08-01

    We utilized high-density Affymetrix oligonucleotide arrays to investigate gene expression in the olfactory mucosae of near age-matched aging senescence-accelerated mice (SAM). The senescence-prone (SAMP) strain has a significantly shorter lifespan than does the senescence-resistant (SAMR) strain. To analyze our data, we applied biostatistical methods that included a correlation analysis to evaluate sources of methodologic and biological variability; a two-sided t-test to identify a subpopulation of Present genes with a biologically relevant P-value <0.05; and a false discovery rate (FDR) analysis adjusted to a stringent 5% level that yielded 127 genes with a P-value of <0.001 that were differentially regulated in near age-matched SAMPs (SAMP-Os; 13.75 months) compared to SAMRs (SAMR-Os, 12.5 months). Volcano plots related the variability in the mean hybridization signals as determined by the two-sided t-test to fold changes in gene expression. The genes were categorized into the six functional groups used previously in gene profiling experiments to identify candidate genes that may be relevant for senescence at the genomic and cellular levels in the aging mouse brain (Lee et al. [2000] Nat Genet 25:294-297) and in the olfactory mucosa (Getchell et al. [2003] Ageing Res Rev 2:211-243), which serves several functions that include chemosensory detection, immune barrier function, xenobiotic metabolism, and neurogenesis. Because SAMR-Os and SAMP-Os have substantially different median lifespans, we related the rate constant alpha in the Gompertz equation on aging to intrinsic as opposed to environmental mechanisms of senescence based on our analysis of genes modulated during aging in the olfactory mucosa. PMID:15248299

  8. Comprehending how visual context influences incremental sentence processing: Insights from ERPs and picture-sentence verification.

    PubMed

    Knoeferle, Pia; Urbach, Thomas P; Kutas, Marta

    2011-04-01

    To re-establish picture-sentence verification-discredited possibly for its over-reliance on post-sentence response time (RT) measures-as a task for situated comprehension, we collected event-related brain potentials (ERPs) as participants read a subject-verb-object sentence, and RTs indicating whether or not the verb matched a previously depicted action. For mismatches (vs. matches), speeded RTs were longer, verb N400s over centro-parietal scalp larger, and ERPs to the object noun more negative. RTs (congruence effect) correlated inversely with the centro-parietal verb N400s, and positively with the object ERP congruence effects. Verb N400s, object ERPs, and verbal working memory scores predicted more variance in RT effects (50%) than N400s alone. Thus, (1) verification processing is not all post-sentence; (2) simple priming cannot account for these results; and (3) verification tasks can inform studies of situated comprehension.

  9. Seismoacoustic responses to high-power electric pulses from well logging data at the Bishkek geodynamical test area

    NASA Astrophysics Data System (ADS)

    Zakupin, A. S.; Bogomolov, L. M.; Mubassarova, V. A.; Il'ichev, P. V.

    2014-09-01

    The results of recording seismoacoustic emission (SAE) in the boreholes of the Bishkek geodynamical test area in Tien Shan, Kyrgyzstan, are presented. The spectral structure of SAE signals and the pattern of variations in SAE intensity during electromagnetic (EM) sounding of the Earth's crust by the highpower ERGU-600-2 generator unit are studied. The statistical methods for SAE data processing are adjusted for the problem of revealing the correlations between SAE responses and pulsed electrical impacts (i.e., energy input into the medium). The response of the medium to EM soundings, which are conducted for monitoring the apparent resistivity of the rocks, is revealed. The response of the medium manifests itself as the increase in SAE intensity (the responses to the electric current pulses generated during the soundings). The SAE responses belong to the same group of the effects (the signs of external forcing of rock destruction) as the variations in seismicity during the runs of the geophysical magneto-hydrodynamic (MHD) generators in 1983-1989 or experimental soundings in 2000-2005. The sources of SAE signals are located at shallow depths, near the geophone installation place. This accounts for the difference between the variations in SAE intensity and microseismicity in response to the same impact.

  10. Areal rainfall construction and estimation of extreme quantiles.

    NASA Astrophysics Data System (ADS)

    Penot, David; Paquet, Emmanuel; Lang, Michel

    2014-05-01

    Areal rainfall estimation and extrapolation to extremes is a key issue for catchment flood study. It is a tricky problem which deals with spatial interpolation (to build an estimate at the catchment's scale based on few rain gauges only), and probabilistic extrapolation (for extreme values estimation). In this study, several methods to build an areal rainfall estimation are compared. The first method is the commonly used Thiessen polygons. A second way to build an areal rainfall relies on the SPAZM method [Gottardi, 2012], in which daily rain fields are reconstructed at a 1km2 resolution, with an interpolation scheme integrating the altitude of the pixel and the weather type of the day. These two methods are compared to the stochastic rain field simulator SAMPO [Leblois et Creutin, 2013], which is an adaptation of the turning band method allowing to generate over 50 years of realistic rain fields. Several questions are tackled in this study: In a Thiessen estimation, how many rain gauges should be selected ? Which weighting scheme should be used ? SPAZM is an interpolator designed to produce unbiased mean annual precipitation (MAP) at a catchment's scale. So if a Thiessen areal rainfall is scaled to fit the MAP given by SPAZM, how does it affect its extreme rainfall estimation ? If a virtual rain gauges network is extracted from the rain fields generated by SAMPO, how do behave the Thiessen and SPAZM areal rainfall estimations based on these point values ? At the end, some abatement functions are obtained, showing the influence of the catchment's area and the options chosen to build the areal rainfall estimations. References: F. Gottardi, C. Obled, J. Gailhard, and E. Paquet, Statistical reanalysis of precipitation fields based on ground network data and weather patterns : Application over french mountains. Journal of Hydrology, 432-433:154 - 167, 2012. ISSN 0022-1694. E. Leblois and J-D. Creutin, Space-time simulation of intermittent rainfall with prescribed

  11. Determination of trace elements by instrumental neutron activation analysis in Anatolian bentonitic clays

    NASA Astrophysics Data System (ADS)

    Güngör, N.; Tulun, T.; Alemdar, A.

    1998-08-01

    Instrumental Neutron Activation Analysis (INAA) was carried out for the determination of trace elements in non-swelling type bentonitic clays. Samples were irradiated in Triga Mark II type of reactor at the Nuclear Institute of Technical University of Istanbul. Irradiation was performed in two steps for "short and long lived" isotopes. The γ spectra of short lived isotopes were interpreted with respect to Al, Ca, Mg, Na, K, Ti, Mn, V qualitatively and that of long lived isotopes with respect to Sc, Cr, Br, Sb, Cs, La, Ce, Sm, Yb, Hf quantitatively. The relative richness of the trace elements (Al, Ti, Ca, Mg, Na, K) observed in the Sampo 90 program was obtained using Atomic Absorption technique by normalizing its value to that of sodium. The silicon content of samples was determined by gravimetry. The results indicated that Sample I contained relatively higher amount of REE, Sb, Ca and Na than Sample II. The amount of Sc, Cr and Br were about similar in both samples. Concentrations of La, Ce, Sm and Yb are higher than REE abundances found in all natural waters. These results suggest that Ca-bentonite samples are representative of primary deposition environment. In addition, the Sc content of both the samples indicates that Ca-bentonite deposits originated from continental crust. The relatively high amount of REE might bring about porosity problems in the use of Ca-bentonite in cement and concrete production.

  12. Astrobiology Exploration Strategies for the Mars Polar Regions Using Balloon Platforms

    NASA Technical Reports Server (NTRS)

    Mahaffy, P. R.; Atreya, S. A.; Fairbrother, D. A.; Farrell, W. M.; Gorevan, S.; Jones, J.; Mitrofanov, I.; Scott, J.

    2003-01-01

    Montgolfiere balloons can provide a unique near-surface platform for an extended traverse over the polar regions of Mars. During the polar summer, such solar powered balloons would remain in the constant sun of the polar summer and could remain airborne for many weeks or even months as the atmospheric circulation would drive the balloons around the polar region many times before the balloon would cross the terminator. Such a platform for scientific measurements could provide in situ sampling of the atmosphere for trace disequilibrium species that might be indicators of present geological or biological activity in this regon. It could furthermore provide high resolution imaging, deep electromagnetic (EM) sounding for subsurface stratigraphy and liquid water, and high spatial resolution neutron measurements of subsurface ice. Technologies for robust balloon deployment on entry and controlled encounters with the surface and near subsurface for sample acquisition in otherwise inaccessible regions are presently being studied and developed with support from NASA.

  13. Astrobiology Exploration Strategies for the Mars Polar Regions Using Balloon Platforms

    NASA Technical Reports Server (NTRS)

    Mahaffy, P. R.; Atreya, S. A.; Fairbrother, D. A.; Farrell, W. M.; Gorevan, S.; Jones, J.; Mitrofanov, I.; Scott, J.

    2003-01-01

    Montgolfiere balloons can provide a unique near-surface platform for an extended traverse over the polar regions of Mars. During the polar summer, such solar powered balloons would remain in the constant sun of the polar summer and could remain airborne for many weeks or even months as the atmospheric circulation would drive the balloons around the polar region many times before the balloon would cross the terminator. Such a platform for scientific measurements could provide in situ sampling of the atmosphere for trace disequilibrium species that might be indicators of present geological or biological activity in this region. It could furthermore provide high resolution imaging, deep electromagnetic (EM) sounding for subsurface stratigraphy and liquid water, and high spatial resolution neutron measurements of subsurface ice. Technologies for robust balloon deployment on entry and controlled encounters with the surface and near subsurface for sample acquisition in otherwise inaccessible regions are presently being studied and developed with support from NASA.

  14. IBM Application System/400 as the foundation of the Mayo Clinic/IBM PACS project

    NASA Astrophysics Data System (ADS)

    Rothman, Melvyn L.; Morin, Richard L.; Persons, Kenneth R.; Gibbons, Patricia S.

    1990-08-01

    An IBM Application System/400 (AS/400) anchors the Mayo Clinic/IBM joint development PACS project. This paper highlights some of the AS/400's features and the resulting benefits which make it a strong foundation for a medical image archival and review system. Among the AS/400's key features are: 1. A high-level machine architecture 2. Object orientation 3. Relational data base and other functions integrated into the system's architecture 4. High-function interfaces to IBM Personal Computers and IBM Personal System/2s' (pS/2TM).

  15. Distinguishing lexical- versus discourse-level processing using event-related potentials

    PubMed Central

    Huang, Yi Ting; Hopfinger, Joseph; Gordon, Peter C.

    2013-01-01

    Two experiments examine the links between neural patterns in EEG (e.g., N400s, P600s) and their corresponding cognitive processes (e.g., lexical access, discourse integration) by varying the lexical and syntactic contexts of co-referential expressions. Experiment 1 examined coreferring expressions when they occurred within the same clause as their antecedents (John/Bill warmly dressed John). Experiment 2 examined between-clause co-referencing with expressions that also varied in lexical frequency (John/Weston went to the store so that John/Weston could buy milk). Evidence of facilitated lexical processing occurred after repeated names, which elicited smaller N400s, as compared with new names. N400s were also attenuated to a greater degree for low-frequency expressions than for high-frequency ones. Repeated names also triggered evidence of postlexical processing, but this emerged as larger P600s for within-clause co-referencing and delayed N400s for between-clause co-referencing. Together, these results suggest that linguistic processes can be distinguished through distinct ERP components or distinct temporal patterns. PMID:24122362

  16. Quantifiers More or Less Quantify On-Line: ERP Evidence for Partial Incremental Interpretation

    ERIC Educational Resources Information Center

    Urbach, Thomas P.; Kutas, Marta

    2010-01-01

    Event-related brain potentials were recorded during RSVP reading to test the hypothesis that quantifier expressions are incrementally interpreted fully and immediately. In sentences tapping general knowledge ("Farmers grow crops/worms as their primary source of income"), Experiment 1 found larger N400s for atypical ("worms") than typical objects…

  17. Low-Frequency Electromagnetic Sounding for Planetary Volatiles (Invited)

    NASA Astrophysics Data System (ADS)

    Grimm, R. E.

    2013-12-01

    EM sounding is divided by loss tangent << 1 (surface-penetrating radars) and >> 1 (inductive methods). The former have high resolution and responses dominated by dielectric permittivity. They have been useful for sounding the polar caps of Mars and are very promising to image the shells of icy satellites as well as the uppermost crusts of silicate bodies. The latter have poorer resolution but greater penetration depth, responses dominated by electrical conductivity, and are the subject of this talk. Low-frequency inductive methods are further divided by comparing the source-receiver separation to the skin depth. Large separations are parametric in frequency so that the variation of EM response with frequency is translated to change in conductivity with depth. Parametric soundings can exploit natural sources from the solar wind, magnetosphere, ionosphere, or atmosphere. Small source-sensor separations are geometric with transmitter-receiver positions: both conductivity and permittivity can be recovered as a function of frequency (a dielectric spectrum), but at greater resource requirements. Subsurface liquid water is an optimal low-frequency EM target because even small quantities of dissolved ions make it a powerful electrical conductor compared to dry, resistive, silicate crusts. Water at kms or even tens of kms can be detected using the magnetotelluric, geomagnetic-depth sounding, or wave-tilt methods: these are all natural-source soundings using different combinations of field components and receiver geometries. If natural sources are weak or absent, a transmitter can be used to obtain high SNR; the time-domain EM (TDEM) method has been used extensively for terrestrial groundwater exploration. Using a ballistically deployed 200-m diameter transmitter loop, TDEM can detect groundwater at depths of several km. If landed in a region of strong local crustal magnetism, the characteristic Larmor frequency of liquid water can be detected with a TDEM-like setup using

  18. Lexical selection differences between monolingual and bilingual listeners.

    PubMed

    Friesen, Deanna C; Chung-Fat-Yim, Ashley; Bialystok, Ellen

    2016-01-01

    Three studies are reported investigating how monolinguals and bilinguals resolve within-language competition when listening to isolated words. Participants saw two pictures that were semantically-related, phonologically-related, or unrelated and heard a word naming one of them while event-related potentials were recorded. In Studies 1 and 2, the pictures and auditory cue were presented simultaneously and the related conditions produced interference for both groups. Monolinguals showed reduced N400s to the semantically-related pairs but there was no modulation in this component by bilinguals. Study 3 inserted an interval between picture and word onset. For picture onset, both groups exhibited reduced N400s to semantically-related pictures; for word onset, both groups showed larger N400s to phonologically-related pictures. Overall, bilinguals showed less integration of related items in simultaneous (but not sequential) presentation, presumably because of interference from the activated non-English language. Thus, simple lexical selection for bilinguals includes more conflict than it does for monolinguals.

  19. Lexical selection differences between monolingual and bilingual listeners.

    PubMed

    Friesen, Deanna C; Chung-Fat-Yim, Ashley; Bialystok, Ellen

    2016-01-01

    Three studies are reported investigating how monolinguals and bilinguals resolve within-language competition when listening to isolated words. Participants saw two pictures that were semantically-related, phonologically-related, or unrelated and heard a word naming one of them while event-related potentials were recorded. In Studies 1 and 2, the pictures and auditory cue were presented simultaneously and the related conditions produced interference for both groups. Monolinguals showed reduced N400s to the semantically-related pairs but there was no modulation in this component by bilinguals. Study 3 inserted an interval between picture and word onset. For picture onset, both groups exhibited reduced N400s to semantically-related pictures; for word onset, both groups showed larger N400s to phonologically-related pictures. Overall, bilinguals showed less integration of related items in simultaneous (but not sequential) presentation, presumably because of interference from the activated non-English language. Thus, simple lexical selection for bilinguals includes more conflict than it does for monolinguals. PMID:26684415

  20. Integrated interpretation of overlapping AEM datasets achieved through standardisation

    NASA Astrophysics Data System (ADS)

    Sørensen, Camilla C.; Munday, Tim; Heinson, Graham

    2015-12-01

    Numerous airborne electromagnetic surveys have been acquired in Australia using a variety of systems. It is not uncommon to find two or more surveys covering the same ground, but acquired using different systems and at different times. Being able to combine overlapping datasets and get a spatially coherent resistivity-depth image of the ground can assist geological interpretation, particularly when more subtle geophysical responses are important. Combining resistivity-depth models obtained from the inversion of airborne electromagnetic (AEM) data can be challenging, given differences in system configuration, geometry, flying height and preservation or monitoring of system acquisition parameters such as waveform. In this study, we define and apply an approach to overlapping AEM surveys, acquired by fixed wing and helicopter time domain electromagnetic (EM) systems flown in the vicinity of the Goulds Dam uranium deposit in the Frome Embayment, South Australia, with the aim of mapping the basement geometry and the extent of the Billeroo palaeovalley. Ground EM soundings were used to standardise the AEM data, although results indicated that only data from the REPTEM system needed to be corrected to bring the two surveys into agreement and to achieve coherent spatial resistivity-depth intervals.

  1. Determining salinization extent, identifying salinity sources, and estimating chloride mass using surface, borehole, and airborne electromagnetic induction methods

    NASA Astrophysics Data System (ADS)

    Paine, Jeffrey G.

    2003-03-01

    Using an example from an oil field in the semiarid Red River basin in Texas, we show that electromagnetic (EM) methods are useful in locating salinized soil and water, determining salinization extent, identifying likely salinity sources, and estimating the total mass of chloride within a saline-water plume. Each of these aspects assists in managing salinization and assessing its impact. We used ground EM instruments to establish salinization boundaries and determine the range of electrical conductivity, airborne measurements to locate potential sources and quantify the lateral extent and intensity of salinization, and borehole measurements and time domain EM soundings to determine salinization depth and relate ground conductivity to chloride content. We estimated infiltration volume and total chloride mass in the plume from EM data and an empirical, site-specific chloride:conductivity ratio established from well data. Because the measured conductivity of water strongly correlates with total dissolved solids concentration, mass estimation could be extended to any ionic constituent that covaries linearly with total dissolved solids concentration. EM methods owe their success to the large increase in electrical conductivity that occurs where highly conductive, saline water infiltrates geologic materials having naturally low conductivities.

  2. Chondroprotective supplementation promotes the mechanical properties of injectable scaffold for human nucleus pulposus tissue engineering.

    PubMed

    Foss, Berit L; Maxwell, Thomas W; Deng, Ying

    2014-01-01

    A result of intervertebral disc (IVD) degeneration, the nucleus pulposus (NP) is no longer able to withstand applied load leading to pain and disability. The objective of this study is to fabricate a tissue-engineered injectable scaffold with chondroprotective supplementation in vitro to improve the mechanical properties of a degenerative NP. Tissue-engineered scaffolds were fabricated using different concentrations of alginate and calcium chloride and mechanically evaluated. Fabrication conditions were based on structural and mechanical resemblance to the native NP. Chondroprotective supplementation, glucosamine (GCSN) and chondroitin sulfate (CS), were added to scaffolds at concentrations of 0:0µg/mL (0:0-S), 125:100µg/mL (125:100-S), 250:200µg/mL (250:200-S), and 500:400µg/mL (500:400-S), GCSN and CS, respectively. Scaffolds were used to fabricate tissue-engineered constructs through encapsulation of human nucleus pulposus cells (HNPCs). The tissue-engineered constructs were collected at days 1, 14, and 28 for biochemical and biomechanical evaluations. Confocal microscopy showed HNPC viability and rounded morphology over the 28 day period. MTT analysis resulted in significant increases in cell proliferation for each group. Collagen type II ELISA quantification and compressive aggregate moduli (HA) showed increasing trends for both 250:200-S and the 500:400-S groups on Day 28 with significantly greater HA compared to 0:0-S group. Glycosaminoglycan and water content decreased for all groups. Results indicate the increased mechanical properties of the 250:200-S and the 500:400-S was due to production of a functional matrix. This study demonstrated potential for a chondroprotective supplemented injectable scaffold to restore biomechanical function of a degenerative disc through the production of a mechanically functional matrix. PMID:24055794

  3. Chondroprotective supplementation promotes the mechanical properties of injectable scaffold for human nucleus pulposus tissue engineering.

    PubMed

    Foss, Berit L; Maxwell, Thomas W; Deng, Ying

    2014-01-01

    A result of intervertebral disc (IVD) degeneration, the nucleus pulposus (NP) is no longer able to withstand applied load leading to pain and disability. The objective of this study is to fabricate a tissue-engineered injectable scaffold with chondroprotective supplementation in vitro to improve the mechanical properties of a degenerative NP. Tissue-engineered scaffolds were fabricated using different concentrations of alginate and calcium chloride and mechanically evaluated. Fabrication conditions were based on structural and mechanical resemblance to the native NP. Chondroprotective supplementation, glucosamine (GCSN) and chondroitin sulfate (CS), were added to scaffolds at concentrations of 0:0µg/mL (0:0-S), 125:100µg/mL (125:100-S), 250:200µg/mL (250:200-S), and 500:400µg/mL (500:400-S), GCSN and CS, respectively. Scaffolds were used to fabricate tissue-engineered constructs through encapsulation of human nucleus pulposus cells (HNPCs). The tissue-engineered constructs were collected at days 1, 14, and 28 for biochemical and biomechanical evaluations. Confocal microscopy showed HNPC viability and rounded morphology over the 28 day period. MTT analysis resulted in significant increases in cell proliferation for each group. Collagen type II ELISA quantification and compressive aggregate moduli (HA) showed increasing trends for both 250:200-S and the 500:400-S groups on Day 28 with significantly greater HA compared to 0:0-S group. Glycosaminoglycan and water content decreased for all groups. Results indicate the increased mechanical properties of the 250:200-S and the 500:400-S was due to production of a functional matrix. This study demonstrated potential for a chondroprotective supplemented injectable scaffold to restore biomechanical function of a degenerative disc through the production of a mechanically functional matrix.

  4. Discovery of Three Apparent Novae in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Vaduvescu, O.; Oers, P. van

    2013-02-01

    We report the discovery of three apparent novae in the M81 galaxy on a co-added 3200-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma in ~1.4" seeing on Feb. 25.132 UT. The new objects are visible on individual 400-s frames and well visible on the co-added image (see the finding chart linked below), but are not present on numerous narrow-band H-alpha archival images from the INT down to limiting magnitude as faint as H-alpha = 22.5.

  5. Discovery of Two Novae in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Vaduvescu, O.; Zurita, C.; Patrick, L.; Ledo, H.; Karjalainen, R.

    2012-05-01

    We report the discovery of two novae in M81 on a co-added 1600-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~0.8" seeing on May 22.901 UT. The new objects are well visible on the co-added image (see the finding chart linked below) as well as on individual 400-s frames, but are not present on numerous narrow-band H-alpha archival images from the INT down to limiting magnitude as faint as H-alpha = 22.3.

  6. Discovery of Two Probable Novae in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Patrick, L.; Arnold, D.; Dominguez, L.; Fernandez, A. Gonzalez; Hardy, L.; Hrudkova, M.; Van Oers, P.; Ramanjooloo, Y.; Karjalainen, R.; Vaduvescu, O.

    2012-10-01

    We report the discovery of two probable novae in the M81 galaxy on a co-added 1600-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma on Sep. 28.233 UT. The new objects are well visible on the co-added image (see the finding chart linked below) and faintly visible on individual 400-s frames, but are not present on numerous narrow-band H-alpha archival images from the INT down to limiting magnitude as faint as H-alpha = 22.3.

  7. Discovery of Two Apparent Novae in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; McCormac, J.; Vaduvescu, O.

    2013-06-01

    We report the discovery of two apparent novae in the M81 galaxy on a co-added 1600-s, narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma in ~1.5" seeing on 2013 June 3.905 UT. The new objects are visible on individual 400-s frames and well visible on the co-added image (see the finding chart linked below), but are not present on numerous narrow-band H-alpha archival images from the INT down to a limiting magnitude as faint as H-alpha = 22.7.

  8. Discovery of an Apparent Nova in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Vaduvescu, O.; Gonzalez, A.

    2013-04-01

    We report the discovery of an apparent nova in the M81 galaxy on a co-added 2000-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma in ~1.4" seeing on Apr. 5.946 UT. The new object is visible on individual 400-s frames and well visible on the co-added image (see the finding chart linked below), but is not present on numerous narrow-band H-alpha archival images from the INT down to limiting magnitude as faint as H-alpha = 21.7.

  9. Quantifiers more or less quantify online: ERP evidence for partial incremental interpretation

    PubMed Central

    Urbach, Thomas P.; Kutas, Marta

    2010-01-01

    Event-related brain potentials were recorded during RSVP reading to test the hypothesis that quantifier expressions are incrementally interpreted fully and immediately. In sentences tapping general knowledge (Farmers grow crops/worms as their primary source of income), Experiment 1 found larger N400s for atypical (worms) than typical objects (crops). Experiment 2 crossed object typicality with non-logical subject-noun phrase quantifiers (most, few). Off-line plausibility ratings exhibited the crossover interaction predicted by full quantifier interpretation: Most farmers grow crops and Few farmers grow worms were rated more plausible than Most farmers grow worms and Few farmers grow crops. Object N400s, although modulated in the expected direction, did not reverse. Experiment 3 replicated these findings with adverbial quantifiers (Farmers often/rarely grow crops/worms). Interpretation of quantifier expressions thus is neither fully immediate nor fully delayed. Furthermore, object atypicality was associated with a frontal slow positivity in few-type/rarely quantifier contexts, suggesting systematic processing differences among quantifier types. PMID:20640044

  10. Close, but no garlic: Perceptuomotor and event knowledge activation during language comprehension

    PubMed Central

    Amsel, Ben D.; DeLong, Katherine A.; Kutas, Marta

    2015-01-01

    Recent research has shown that language comprehension is guided by knowledge about the organization of objects and events in long-term memory. We use event-related brain potentials (ERPs) to determine the extent to which perceptuomotor object knowledge and event knowledge are immediately activated during incremental language processing. Event-related but anomalous sentence continuations preceded by single-sentence event descriptions elicited reduced N400s, despite their poor fit within local sentence contexts. Anomalous words sharing particular sensory or motor attributes with contextually expected words also elicited reduced N400s, despite being inconsistent with global context (i.e., event information). We rule out plausibility as an explanation for both relatedness effects. We show that perceptuomotor-related facilitation is not due to lexical priming between words in the local context and the target or to associative or categorical relationships between expected and unexpected targets. Overall our results are consistent with the immediate and incremental activation of perceptual and motor object knowledge and generalized event knowledge during sentence processing. PMID:25897182

  11. Comparison of Hemostatic Durability between N-Butyl Cyanoacrylate and Gelatin Sponge Particles in Transcatheter Arterial Embolization for Acute Arterial Hemorrhage in a Coagulopathic Condition in a Swine Model

    SciTech Connect

    Yonemitsu, Takafumi; Kawai, Nobuyuki; Sato, Morio Sonomura, Tetsuo; Takasaka, Isao; Nakai, Motoki; Minamiguchi, Hiroki; Sahara, Shinya; Iwasaki, Yasuhiro; Naka, Toshio; Shinozaki, Masahiro

    2010-12-15

    This study was designed to compare the efficacy of transcatheter arterial embolization (TAE) with N-butyl cyanoacrylate (NBCA) or gelatin sponge particles (GSP) for acute arterial bleeding in a coagulopathic condition using a swine model. Four healthy swine were divided into two coagulopathic conditions: mild and severe. Five hemorrhages were created in each swine (10 hemorrhages per coagulopathy). Mild coagulopathy was achieved by bloodletting 10% of the total circulatory whole blood and preserving activated clotting time (ACT) less than 200 s (ACT < 200 s state); severe coagulopathy was achieved by bloodletting 30% and preserving ACT > 400 s (ACT > 400-second state). For each state, of ACT < 200 s or ACT > 400 s, TAE was conducted with GSP or NBCA to control five hemorrhages arising from artificially created renal and splenic injuries. Angiography immediately after TAE with GSP or NBCA showed complete occlusion in both coagulopathic conditions. In the ACT < 200-second state, follow-up angiography at 5-30 min after TAE with GSP or NBCA showed no evidence of recurrent hemorrhage. In the ACT > 400-second state, follow-up angiography showed recurrent hemorrhage in four (80%) of the five hemorrhages embolized with GSP and in one (20%) of the five hemorrhages embolized with NBCA. Microscopically, red thrombi were observed densely surrounding GSP in mild coagulopathy but were scarce in severe coagulopathy. In a condition with severe coagulopathy, TAE with NBCA was more effective in durability to cease active arterial bleeding than with GSP.

  12. Study of medical isotope production facility stack emissions and noble gas isotopic signature using automatic gamma-spectra analysis platform

    NASA Astrophysics Data System (ADS)

    Zhang, Weihua; Hoffmann, Emmy; Ungar, Kurt; Dolinar, George; Miley, Harry; Mekarski, Pawel; Schrom, Brian; Hoffman, Ian; Lawrie, Ryan; Loosz, Tom

    2013-04-01

    The nuclear industry emissions of the four CTBT (Comprehensive Nuclear-Test-Ban Treaty) relevant radioxenon isotopes are unavoidably detected by the IMS along with possible treaty violations. Another civil source of radioxenon emissions which contributes to the global background is radiopharmaceutical production companies. To better understand the source terms of these background emissions, a joint project between HC, ANSTO, PNNL and CRL was formed to install real-time detection systems to support 135Xe, 133Xe, 131mXe and 133mXe measurements at the ANSTO and CRL 99Mo production facility stacks as well as the CANDU (CANada Deuterium Uranium) primary coolant monitoring system at CRL. At each site, high resolution gamma spectra were collected every 15 minutes using a HPGe detector to continuously monitor a bypass feed from the stack or CANDU primary coolant system as it passed through a sampling cell. HC also conducted atmospheric monitoring for radioxenon at approximately 200 km distant from CRL. A program was written to transfer each spectrum into a text file format suitable for the automatic gamma-spectra analysis platform and then email the file to a server. Once the email was received by the server, it was automatically analysed with the gamma-spectrum software UniSampo/Shaman to perform radionuclide identification and activity calculation for a large number of gamma-spectra in a short period of time (less than 10 seconds per spectrum). The results of nuclide activity together with other spectrum parameters were saved into the Linssi database. This database contains a large amount of radionuclide information which is a valuable resource for the analysis of radionuclide distribution within the noble gas fission product emissions. The results could be useful to identify the specific mechanisms of the activity release. The isotopic signatures of the various radioxenon species can be determined as a function of release time. Comparison of 133mXe and 133Xe activity

  13. An electromagnetic sounding experiment in Germany using the vertical gradient of geomagnetic variations observed in a deep borehole

    NASA Astrophysics Data System (ADS)

    Schmucker, Ulrich; Spitzer, Klaus; Steveling, Erich

    2009-09-01

    We have recorded for 13 d, geomagnetic variations simultaneously on the Earth's surface and in a borehole at 832 m depth straight below, with a sampling rate of 1 Hz. In addition, geoelectric variations were observed at the same site near Bad Königshofen in Frankonia, Germany. The penetrated moderately conductive Triassic sediments lie above highly resistive Permian deposits. A presumably crystalline basement begins at 1500-1900 m depth. The purpose of the experiment is to determine the skin effect of geomagnetic variations and to derive from it the equivalent to the magnetotelluric (MT) surface impedance, using the vertical gradient (VG) method of electromagnetic (EM) sounding. In this way, we were able to reproduce all four elements of the MT impedance tensor, except for an unexplained but consistent downward shift of VG phases against MT phases by roughly 15° for the two off-diagonal elements. Hence, our tensor evaluation goes beyond the common practice, to express the skin effect by a single VG transfer function in response to a layered structure. The otherwise good agreement of VG and MT results implies that at our test site, the MT impedance tensor is largely distortion-free and that, for example, its pronounced anisotropy should be regarded as a genuine characteristic of the EM response for a laterally non-uniform or possibly anisotropic deep structure. The drilling site lies within the range of a widespread induction anomaly. We have observed the resulting variations of the vertical magnetic component at the surface and in the borehole and found them to be identical. The thus established absence of a skin effect for the vertical component allows us to treat the sedimentary layer down to the depth of the borehole instrument as a thin sheet, and the pertinent thin-sheet approximation for EM induction forms the basis of our analysis. We have derived the required estimate of conductance from the skin effect of horizontal components, noting that this estimate

  14. Jupiter's and Saturn's ice moons: geophysical aspects and opportunities of geophysical survey of the planetary geoelectrical markers and oreols of the subsurface liquid ocean on the surface ice moons

    NASA Astrophysics Data System (ADS)

    Ozorovich, Yuri; Linkin, Vacheslav; Kosov, Alexandr; Fournier-Sicre, Alain; Klimov, Stanislav; Novikov, Denis; Ivanov, Anton; Skulachev, Dmitriy; Menshenin, Yaroslav

    2016-04-01

    ]https://www.researchgate.net/publication/282151921_JUPITER%27S_MOON_EUROPA_PLANETARY_GEOELECTRICAL_MARKER_AND_OREOLS_UNDER_ICE_SUBSUEFACE_OCEAN_ON_THE_SURFACE_OF_THE_JUPITER%27S_MOON_EUROPA?ev=prf_pub [2]https://www.researchgate.net/publication/281270655_YUPITERS_MOON_EUROPA_PLANETARY_GEOELECTRICAL_MARKERS_AND_OREOPLS_OF_THE_LIQUID_OCEAN_UNDER_THE_ICE_ON_THE_SURFACE_OF_THE_YUPITERS_MOON_EUROPE [3] https://www.researchgate.net/publication/276005128_Science-technology_aspects_and_opportunities_of_em_sounding_frozen_%28_permafrost%29_soil [4]https://www.researchgate.net/publication/275638508_Cryolitozone_of_Mars_-_as_the_climatic_indicator_of_the_Martian_relict_ocean [5]https://www.researchgate.net/publication/275266762_Microwave_remote_sensing_of_Martian_cryolitozone

  15. Express and low-cost microwave synthesis of the ternary Chevrel phase Cu2Mo6S8 for application in rechargeable magnesium batteries

    NASA Astrophysics Data System (ADS)

    Murgia, Fabrizio; Antitomaso, Philippe; Stievano, Lorenzo; Monconduit, Laure; Berthelot, Romain

    2016-10-01

    The ternary Chevrel phase Cu2Mo6S8 was successfully synthetized using a simple and cost-effective solid-state microwave-assisted reaction. While solid-state routes require days of high-temperature treatment under inert atmosphere, highly pure and crystalline Cu2Mo6S8 could be obtained in only 400 s from this precursor, the Chevrel binary phase Mo6S8 was then obtained by copper removal through acidic leaching, and was evaluated as a positive electrode material for Mg-battery. The electrochemical performance in half-cell configuration shows reversible capacity exceeding 80 mAh/g, which is comparable to previous works carried out with materials synthesized by conventional high-temperature solid-state routes.

  16. Reflectivity studies on adsorbed block copolymers under shear

    SciTech Connect

    Smith, G.S.; Wages, S.; Baker, S.M.; Toprakcioglu, C.; Hadziioannou, G.

    1994-12-01

    The authors report neutron reflectivity data on (poly)styrene-(poly)ethylene oxide (PS-PEO) diblock copolymers adsorbed onto quartz from the selective solvent cyclohexane (a non-solvent for PEO and a poor solvent for PS). The PEO ``anchor block`` adsorbs strongly to form a thin layer on the quartz substrate, while the deuterated PS chains dangle into the solvent. They find that under static conditions the density profile of the PS block in a poor solvent can be well described by a Schultz function which is indicative of a polymer ``mushroom.`` Furthermore, they have studied the same system under shear at shear rates from 0--400s{sup {minus}1}. They find that there is a dramatic increase in the thickness of the PS layer under shear in cyclohexane and that the relaxation time from the shear-on profile back to the static profile is on the order of several days.

  17. SYNCHROTRON SELF-COMPTON EMISSION AS THE ORIGIN OF THE GAMMA-RAY AFTERGLOW OBSERVED IN GRB 980923

    SciTech Connect

    Fraija, N.; Gonzalez, M. M.; Lee, W. H. E-mail: magda@astro.unam.mx

    2012-05-20

    GRB 980923 was one of the brightest bursts observed by the Burst and Transient Source Experiment. Previous studies have detected two distinct components in addition to the main prompt episode, which is well described by a Band function. The first of these is a tail with a duration of {approx_equal} 400 s, while the second is a high-energy component lasting {approx_equal} 2 s. We summarize the observations and argue for a unified model in which the tail can be understood as the early {gamma}-ray afterglow from forward shock synchrotron emission, while the high-energy component arises from synchrotron self-Compton from the reverse shock. Consistency between the main assumption of thick shell emission and agreement between the observed and computed values for fluxes, break energies, starting times, and spectral indices leads to a requirement that the ejecta must be highly magnetized.

  18. Rapid, Site-Selective Loading of a Scalable Array of Trapped Ions

    NASA Astrophysics Data System (ADS)

    Bruzewicz, Colin; McConnell, Robert; Chiaverini, John; Sage, Jeremy

    2016-05-01

    Rapid trap reloading is a requirement for any scalable quantum information processor based on trapped-ion qubits. Even cryogenic systems with trap lifetimes in excess of 10 hours will require loading rates of approximately 100 s-1 to maintain arrays of millions of ions. Further, the reloading process should not introduce unacceptable levels of decoherence into other ions within the array. Here, we demonstrate rapid, site-selective, random-access loading of a 2x2 array of trapped ions that satisfies the major criteria for scalable quantum processing. This scheme uses a continuous flux of pre-cooled strontium atoms and a pair of orthogonal photo-ionization lasers to load surface-electrode point Paul traps at average rates greater than 400 s-1. Additionally, we have conducted a series of Ramsey experiments to measure the effects of loading on the coherence of nearby trapped ions.

  19. Familiarity or conceptual priming? Good question! Comment on Stenberg, Hellman, Johansson, and Rosén (2009).

    PubMed

    Lucas, Heather D; Voss, Joel L; Paller, Ken A

    2010-04-01

    Stenberg et al. argued that FN400 brain potentials index familiarity rather than conceptual priming. Their data from a test of name recognition showed that both familiarity and FN400s were influenced by frequency but not fame, whereas separate behavioral measures of priming were influenced by fame but not frequency. However, this apparent dissociation was gravely weakened by confounds in task demands and inadequate behavioral measures of priming. Although Stenberg et al. failed to provide evidence suitable for disentangling neural correlates of familiarity from those of conceptual priming, an analysis of their report can be used to highlight difficulties that remain to be surmounted to understand recognition and the neural events that signal distinct memory functions engaged during recognition.

  20. Confirmation and Photometry of Five Optical Nova Candidates in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Fohring, D.; Karjalainen, R.

    2012-01-01

    We report confirmation of five nova candidates in M81 discovered on 2012 Jan. 9.102 UT (ATEL #3871). On Jan. 21.196 UT we obtained four 400-s narrow-band H-alpha CCD frames with the 2.5-m Isaac Newton Telescope + WFC at La Palma under ~1.5" seeing. The single frames were co-added and the co-added image was used for confirmation of the nova candidates and the photometry. The candidates (except PNV J09553792+6902498, which is visible at the limit) are well visible on the co-added image as well as nova PNV J09553266+6906072 (ATEL #3735, #3770, and #3871) and PNV J09553281+6902028 (ATEL #3867).

  1. Rate equations modeling for hydrogen inventory studies during a real tokamak material thermal cycle

    NASA Astrophysics Data System (ADS)

    Bonnin, X.; Hodille, E.; Ning, N.; Sang, C.; Grisolia, Ch.

    2015-08-01

    Prediction and control of tritium inventory in plasma-facing components (PFCs) is a critical nuclear safety issue for ITER and future fusion devices. This goal can be achieved through rate equations models as presented here. We calibrate our models with thermal desorption spectrometry results to obtain a validated set of material parameters relevant to hydrogen inventory processes in bulk tungsten. The best fits are obtained with two intrinsic trap types, deep and shallow, and an extrinsic trap created by plasma irradiation and plastic deformation of the tungsten matrix associated with blister formation. We then consider a realistic cycle of plasma discharges consisting of 400 s of plasma exposure followed by a resting period of 1000 s, repeating for several hours. This cycle is then closed by a long "overnight" period, thus providing an estimate of the amount of tritium retained in the PFCs after a full day of standard operation.

  2. Chemical and electrical properties of LSM cathodes prepared by mechanosynthesis

    NASA Astrophysics Data System (ADS)

    Moriche, R.; Marrero-López, D.; Gotor, F. J.; Sayagués, M. J.

    2014-04-01

    Mechanosynthesis of La1-xSrxMnO3 (x = 0, 0.25, 0.5, 0.75 and 1) was carried out at room temperature from stoichiometric mixtures of La2O3, Mn2O3 and SrO, obtaining monophasic powders with the perovskite structure. Physical properties of these materials and their chemical compatibility with the electrolyte yttria stabilized zirconia (YSZ), which depend strongly on the La/Sr ratio, were evaluated to corroborate availability to be implemented as cathode material in solid oxide fuel cells (SOFCs). Electrical conductivity values in air ranged between 100 and 400 S cm-1 in the temperature range of 25-850 °C. Samples presented low reactivity with YSZ in the working temperature range (600-1000 °C) maintaining the grain size small enough to preserve the catalytic activity for oxygen reduction.

  3. Schizotypal traits and N400 in healthy subjects.

    PubMed

    Prévost, Marie; Rodier, Mitchell; Renoult, Louis; Kwann, Yvonne; Dionne-Dostie, Emmanuelle; Chapleau, Isabelle; Brodeur, Mathieu; Lionnet, Claire; Debruille, J Bruno

    2010-11-01

    We examined whether correlations previously found between symptoms of schizophrenia patients and the amplitude of an event-related potential (ERP), the N400, could be also found between schizotypal experiences of healthy subjects and the N400. We chose a semantic categorization task previously used with patients. Schizotypal experiences were measured with the schizotypal personality questionnaire (SPQ). The effects of the other factors were controlled for when assessing the correlations between each SPQ factor and N400s. These correlations were assessed at each electrode site to see whether their distribution on the scalp follows that of the N400 effect. Disorganization and interpersonal scores were found to correlate with ERPs in the N400 time window, as previously reported for the comparable symptoms of patients. However, the scalp distribution of these correlations differed from that of the N400 effect.

  4. Effects of event knowledge in processing verbal arguments

    PubMed Central

    Bicknell, Klinton; Elman, Jeffrey L.; Hare, Mary; McRae, Ken; Kutas, Marta

    2010-01-01

    This research tests whether comprehenders use their knowledge of typical events in real time to process verbal arguments. In self-paced reading and event-related brain potential (ERP) experiments, we used materials in which the likelihood of a specific patient noun (brakes or spelling) depended on the combination of an agent and verb (mechanic checked vs. journalist checked). Reading times were shorter at the word directly following the patient for the congruent than the incongruent items. Differential N400s were found earlier, immediately at the patient. Norming studies ruled out any account of these results based on direct relations between the agent and patient. Thus, comprehenders dynamically combine information about real-world events based on intrasentential agents and verbs, and this combination then rapidly influences online sentence interpretation. PMID:21076629

  5. Catalytic igniters and their use to ignite lean hydrogen-air mixtures

    DOEpatents

    McLean, William J.; Thorne, Lawrence R.; Volponi, Joanne V.

    1988-01-01

    A catalytic igniter which can ignite a hydrogen-air mixture as lean as 5.5% hydrogen with induction times ranging from 20 s to 400 s, under conditions which may be present during a loss-of-liquid-coolant accident at a light water nuclear reactor comprises (a) a perforate catalytically active substrate, such as a platinum coated ceramic honeycomb or wire mesh screen, through which heated gases produced by oxidation of the mixture can freely flow and (b) a plurality of thin platinum wires mounted in a thermally conductive manner on the substrate and positioned thereon so as to be able to receive heat from the substrate and the heated gases while also in contact with unoxidized gases.

  6. Dynamic recrystallization in friction surfaced austenitic stainless steel coatings

    SciTech Connect

    Puli, Ramesh Janaki Ram, G.D.

    2012-12-15

    Friction surfacing involves complex thermo-mechanical phenomena. In this study, the nature of dynamic recrystallization in friction surfaced austenitic stainless steel AISI 316L coatings was investigated using electron backscattered diffraction and transmission electron microscopy. The results show that the alloy 316L undergoes discontinuous dynamic recrystallization under conditions of moderate Zener-Hollomon parameter during friction surfacing. - Highlights: Black-Right-Pointing-Pointer Dynamic recrystallization in alloy 316L friction surfaced coatings is examined. Black-Right-Pointing-Pointer Friction surfacing leads to discontinuous dynamic recrystallization in alloy 316L. Black-Right-Pointing-Pointer Strain rates in friction surfacing exceed 400 s{sup -1}. Black-Right-Pointing-Pointer Estimated grain size matches well with experimental observations in 316L coatings.

  7. Gold nanoparticles as electronic bridges for laccase-based biocathodes.

    PubMed

    Gutiérrez-Sánchez, Cristina; Pita, Marcos; Vaz-Domínguez, Cristina; Shleev, Sergey; De Lacey, Antonio L

    2012-10-17

    Direct electron transfer (DET) reactions between redox enzymes and electrodes can be maximized by oriented immobilization of the enzyme molecules onto an electroactive surface modified with functionalized gold nanoparticles (AuNPs). Here, we present such strategy for obtaining a DET-based laccase (Lc) cathode for O(2) electroreduction at low overpotentials. The stable nanostructured enzymatic electrode is based on the step-by-step covalent attachment of AuNPs and Lc molecules to porous graphite electrodes using the diazonium salt reduction strategy. Oriented immobilization of the enzyme molecules on adequately functionalized AuNPs allows establishing very fast DET with the electrode via their Cu T1 site. The measured electrocatalytic waves of O(2) reduction can be deconvoluted into two contributions. The one at lower overpotentials corresponds to immobilized Lc molecules that are efficiently wired by the AuNPs with a heterogeneous electron transfer rate constant k(0) ≫ 400 s(-1). PMID:23004683

  8. Knowledge inhibition and N400: a study with words that look like common words.

    PubMed

    Debruille, J B

    1998-04-01

    In addition to their own representations, low frequency words, such as BRIBE, can covertly activate the representations of higher frequency words they look like (e.g., BRIDE). Hence, look-alike words can activate knowledge that is incompatible with the knowledge corresponding to accurate representations. Comparatively, eccentric words, that is, low frequency words that do not look as much like higher frequency words, are less likely to activate incompatible knowledge. This study focuses on the hypothesis that the N400 component of the event-related potential reflects the inhibition of incompatible knowledge. This hypothesis predicts that look-alike words elicit N400s of greater amplitudes than eccentric words in conditions where incompatible knowledge is inhibited. Results from a single item lexical decision experiment are reported which support the inhibition hypothesis. PMID:9576822

  9. Enhancing charge harvest from microbial fuel cells by controlling the charging and discharging frequency of capacitors.

    PubMed

    Ren, Shiting; Xia, Xue; Yuan, Lulu; Liang, Peng; Huang, Xia

    2013-10-01

    Capacitor is a storage device to harvest charge produced from microbial fuel cells (MFCs). In intermittent charging mode, the capacitor is charged by an MFC first, and then discharged through an external resistance. The charge harvested by capacitor is affected by the charging and discharging frequency. In the present study, the effect of the charging and discharging frequency on charge harvest was investigated. At the switching time (ts) of 100 s, the average current over each time segment reached its maximum value (1.59 mA) the earliest, higher than the other tested conditions, and the highest COD removal (63%) was also obtained, while the coulombic efficiency reached the highest of 67% at the ts of 400 s. Results suggested that lower ts led to higher current output and COD removal, but appropriate ts should be selected in consideration of charge recovery efficiency.

  10. Electromagnetic sounding of Moon's interior -a proposal for Luna-Globe project

    NASA Astrophysics Data System (ADS)

    Korepanov, Valery; Rokityansky, Igor; Dudkin, Fedir; Belyayev, Serhiy; Tereshin, Artem

    The Moon including its deep interior was intensively studied in the time interval 1959-1976, when the data from first lunar missions were recorded, processed and interpreted and the first model of the Moon interior was created. Data of lunar seismology and gravity as well as lunar geography and geology yield clear understanding that lunar crust and mantle are substantially not uniform laterally. Having quite few seismometers and magnetometers at the Moon, only spherically symmetric 1D model of seismic velocities and electrical conductivity was obtained. Next stage of the Moon exploration foresees landing of several robotic missions and it will be then possible to carry out at the Moon's surface geophysical experiments aimed at more careful study of the Moon interior structure. We propose to include in the next planned mission of Russian space program -Luna-Globe -the electromagnetic (EM) sounding of the Moon's mantle in order to clarify more in details its structure. For EM sounding, the spatial-temporal changes of interplanetary magnetic field carried by solar wind (mean intensity 5nT) as well as those of magnetic field in the Earth's magnetosphere tail (˜ 9nT) during its crossing by the Moon may be used. These values define the maximal level of the primary external magnetic field Be. Solar wind magnetic field induces in the Moon mostly poloidal field Bi due to eddy currents driven by variations of Be. For spherically symmetric 1D model, the higher is conductivity of a concentric internal lunar layer, the stronger eddy currents flow in it and the larger is contribution of the layer in Bi, of course, if skin depth is sufficient for this. Poloidal field from deep interior arrives to surface with geometrical attenuation. For example, field produced at Moon surface by currents in conducting layer at the depth R/2 (R = metricconverterProductID1738 km1738 km is Moon radius) attenuates and at the best will be equal to ˜0.1Bi. Practically it means that reliable

  11. Prospects of electromagnetic methods application for evaluation of deep geothermal resources of intraplate regions

    NASA Astrophysics Data System (ADS)

    Pushkarev, P.; Khmelevskoy, V.; Golubtsova, N.

    2013-12-01

    reaches 10 km and more, and in intraplate regions, especially within cratons, the most of it corresponds to consolidated crust. As a result of EM soundings, especially magnetotelluric (MT), a lot of information about crustal conductivity anomalies were obtained. Maps of anomalies were compiled in different scales, from small regions to Northern Eurasia and even the World. Connection between conductivity anomalies and geothermal regime is being studied for several decades. The nature of some anomalies may be caused by modern tectonic activation, followed by magma and fluid intrusions. Many anomalies are connected with deep suture zones, graphitized and/or fluid saturated, which may provide increase heat-and-mass transfer. Therefore, although the nature of some anomalies is still questionable, in our opinion, information about crustal conductivity, in complex with other geological and geophysical data, should be used for petrothermal resources prognosis. This publication is based on work supported by Award No. RUG1-7026-MO-11 of the U.S. Civilian Research & Development Foundation (CRDF) and by the Russian Foundation for Basic Research (RFBR), project 11-05-92501.

  12. A new high-resolution electromagnetic method for subsurface imaging

    NASA Astrophysics Data System (ADS)

    Feng, Wanjie

    high-power (moment of about 6800 Am2) vertical-array DTAC system was designed, developed and tested on controlled buried targets and surface interference to illustrate that the DTAC system was insensitive to surface interference even with a high-power transmitter and having higher resolution by using the large-moment transmitter. From the theoretical and practical analysis and tests, several characteristics of the DTAC method were found: (1) The DTAC method can null out the effect of 1D layered and 2D structures, because magnetic fields are orientation independent which lead to no difference among the null vector directions. This characteristic allows for the measurements of smaller subsurface targets; (2) The DTAC method is insensitive to the orientation errors. It is a robust EM null coupling method. Even large orientation errors do not affect the measured target responses, when a reference frequency and one or more data frequencies are used; (3) The vertical-array DTAC method is effective in reducing the geologic noise and insensitive to the surface interference, e.g., fences, vehicles, power line and buildings; (4) The DTAC method is a high-resolution EM sounding method. It can distinguish the depth and orientation of subsurface targets; (5) The vertical-array DTAC method can be adapted to a variety of rapidly moving survey applications. The transmitter moment can be scaled for effective study of near-surface targets (civil engineering, water resource, and environmental restoration) as well as deep targets (mining and other natural-resource exploration).

  13. Removal of clomazone herbicide from a synthetic effluent by electrocoagulation.

    PubMed

    Benincá, Cristina; Vargas, Fernanda T; Martins, Manoel L; Gonçalves, Fábio F; Vargas, Rodrigo P; Freire, Flavio B; Zanoelo, Everton F

    2016-01-01

    The aim of this work was to investigate the kinetics of removal of clomazone herbicide from an aqueous solution by electrocoagulation. The experiments were performed in a cylindrical batch reactor with six aluminum electrodes in monopolar mode, arranged in series and connected to a digital DC power. The aqueous solution (tap water + clomazone) with initial pH close to 7.9 was always treated at ambient temperature (≈20 °C) and atmospheric pressure for 5,400 s. For a confidence level of 95% the rate constant of electrocoagulation and the efficiency of removal of clomazone at equilibrium were 2.1 × 10(-3) ± 0.5 × 10(-3) s(-1) and 97.7 ± 2.2%, respectively. The final chemical oxygen demand was 88% lower than that measured initially, while turbidity and apparent color were totally removed from the synthetic solution at a rate close to that of formation of aluminum hydroxides. Some reaction intermediates, such as benzonitrile-2-chloro and 2-chloro-hex-2,4-diene-1,6-dioic-acid determined by gas chromatography mass spectrometry (GC-MS) analysis, explain the ratio of equilibrium to initial total organic carbon approximately between 0.6 and 0.8 at a probability of 95%.

  14. Temporal dynamics of lactate concentration in the human brain during acute inspiratory hypoxia

    PubMed Central

    Harris, Ashley D; Roberton, Victoria H; Huckle, Danielle L; Saxena, Neeraj; Evans, C John; Murphy, Kevin; Hall, Judith E; Bailey, Damian M; Mitsis, Georgios; Edden, Richard A E; Wise, Richard G

    2012-01-01

    Purpose To demonstrate the feasibility of measuring the temporal dynamics of cerebral lactate concentration and examine these dynamics in human subjects using MRS during hypoxia. Methods A respiratory protocol consisting of 10 min baseline normoxia, 20 min inspiratory hypoxia and ending with 10 min normoxic recovery was used, throughout which lactate-edited MRS was performed. This was repeated four times in three subjects. A separate session was performed to measure blood lactate. Impulse response functions using end-tidal oxygen and blood lactate as system inputs and cerebral lactate as the system output were examined to describe the dynamics of the cerebral lactate response to a hypoxic challenge. Results The average lactate increase was 20%±15% during the last half of the hypoxic challenge. Significant changes in cerebral lactate concentration were observed after 400s. The average relative increase in blood lactate was 188%±95%. The temporal dynamics of cerebral lactate concentration was reproducibly demonstrated with 200s time bins of MRS data (coefficient of variation 0.063±0.035 between time bins in normoxia). The across subject coefficient of variation was 0.333. Conclusions The methods for measuring the dynamics of the cerebral lactate response developed here would be useful to further investigate the brain’s response to hypoxia. PMID:23197421

  15. Different mechanisms for role relations versus verb-action congruence effects: evidence from ERPs in picture-sentence verification.

    PubMed

    Knoeferle, Pia; Urbach, Thomas P; Kutas, Marta

    2014-10-01

    Extant accounts of visually situated language processing do make general predictions about visual context effects on incremental sentence comprehension; these, however, are not sufficiently detailed to accommodate potentially different visual context effects (such as a scene-sentence mismatch based on actions versus thematic role relations, e.g., (Altmann & Kamide, 2007; Knoeferle & Crocker, 2007; Taylor & Zwaan, 2008; Zwaan & Radvansky, 1998)). To provide additional data for theory testing and development, we collected event-related brain potentials (ERPs) as participants read a subject-verb-object sentence (500 ms SOA in Experiment 1 and 300 ms SOA in Experiment 2), and post-sentence verification times indicating whether or not the verb and/or the thematic role relations matched a preceding picture (depicting two participants engaged in an action). Though incrementally processed, these two types of mismatch yielded different ERP effects. Role-relation mismatch effects emerged at the subject noun as anterior negativities to the mismatching noun, preceding action mismatch effects manifest as centro-parietal N400s greater to the mismatching verb, regardless of SOAs. These two types of mismatch manipulations also yielded different effects post-verbally, correlated differently with a participant's mean accuracy, verbal working memory and visual-spatial scores, and differed in their interactions with SOA. Taken together these results clearly implicate more than a single mismatch mechanism for extant accounts of picture-sentence processing to accommodate.

  16. Study on mitigation of pulsed heat load for ITER cryogenic system

    NASA Astrophysics Data System (ADS)

    Peng, N.; Xiong, L. Y.; Jiang, Y. C.; Tang, J. C.; Liu, L. Q.

    2015-03-01

    One of the key requirements for ITER cryogenic system is the mitigation of the pulsed heat load deposited in the magnet system due to magnetic field variation and pulsed DT neutron production. As one of the control strategies, bypass valves of Toroidal Field (TF) case helium loop would be adjusted to mitigate the pulsed heat load to the LHe plant. A quasi-3D time-dependent thermal-hydraulic analysis of the TF winding packs and TF case has been performed to study the behaviors of TF magnets during the reference plasma scenario with the pulses of 400 s burn and repetition time of 1800 s. The model is based on a 1D helium flow and quasi-3D solid heat conduction model. The whole TF magnet is simulated taking into account thermal conduction between winding pack and case which are cooled separately. The heat loads are given as input information, which include AC losses in the conductor, eddy current losses in the structure, thermal radiation, thermal conduction and nuclear heating. The simulation results indicate that the temperature variation of TF magnet stays within the allowable range when the smooth control strategy is active.

  17. Long-Term Observation of Small and Medium-Scale Gravity Waves over the Brazilian Equatorial Region

    NASA Astrophysics Data System (ADS)

    Essien, Patrick; Buriti, Ricardo; Wrasse, Cristiano M.; Medeiros, Amauri; Paulino, Igo; Takahashi, Hisao; Campos, Jose Andre

    2016-07-01

    This paper reports the long term observations of small and medium-scale gravity waves over Brazilian equatorial region. Coordinated optical and radio measurements were made from OLAP at Sao Joao do Cariri (7.400S, 36.500W) to investigate the occurrences and properties and to characterize the regional mesospheric gravity wave field. All-sky imager measurements were made from the site. for almost 11 consecutive years (September 2000 to November 2010). Most of the waves propagated were characterized as small-scale gravity. The characteristics of the two waves events agreed well with previous gravity wave studies from Brazil and other sites. However, significant differences in the wave propagation headings indicate dissimilar source regions. The observed medium-scale gravity wave events constitute an important new dataset to study their mesospheric properties at equatorial latitudes. These data exhibited similar propagation headings to the short period events, suggesting they originated from the same source regions. It was also observed that some of the medium-scale were capable of propagating into the lower thermosphere where they may have acted directly as seeds for the Rayleigh-Taylor instability development. The wave events were primarily generated by meteorological processes since there was no correlation between the evolution of the wave events and solar cycle F10.7.

  18. Determination of the Free Metal Ion Concentration Using AGNES Implemented with Environmentally Friendly Bismuth Film Electrodes.

    PubMed

    Rocha, Luciana S; Galceran, Josep; Puy, Jaume; Pinheiro, José Paulo

    2015-06-16

    Ex situ plated Bi film electrodes (Bi-FE) have been employed, for the first time, to measure the free concentration of Pb(II) in aqueous solutions using absence of gradients and Nernstian equilibrium stripping (AGNES) with stripping chronopotentiometry (SCP) quantification. The amount of deposited Pb°, below a certain threshold, follows a Nernstian relationship with the applied potential. This threshold can be interpreted as the frontier of transition from surface deposition to solid (bulk) formation of Pb°. AGNES with Bi-FE yielded a very good detection limit (3σ) for Pb(II) of 6.0 × 10(-9) M with an applied gain of 398 and a deposition time of 400 s. The ability of the Bi film electrode to perform speciation measurements was demonstrated for Pb(II)-PSS and Pb(II)-IDA systems. The measured values with the Bi-FE were in good agreement with the values obtained using the Hg film electrode and/or the values reported in the literature.

  19. Brainwaves are stethoscopes: ERP correlates of novel metaphor comprehension.

    PubMed

    Arzouan, Yossi; Goldstein, Abraham; Faust, Miriam

    2007-07-30

    The processing of unfamiliar metaphors was examined using event related potentials (ERPs). We compared the patterns of brain electrical activity elicited by processing two-word expressions denoting literal, conventional metaphoric, and novel metaphoric meaning, as well as unrelated word pairs. Participants performed a semantic judgment task in which they decided whether each word pair conveyed a meaningful expression. N400 amplitude to the second word of the pair varied as a function of expression type in a graded manner increasing from literal expressions to conventional metaphors, to novel metaphors and to unrelated pairs. N400s elicited by novel metaphors showed a right-biased scalp distribution as compared to those elicited by conventional metaphors. Novel metaphors also elicited a right-sided late negativity suggesting further attempts to integrate meaning in a non-literal fashion, a result that supports the sequential view of novel metaphor comprehension. These findings are consistent with recent brain imaging studies and complement them by adding the temporal dynamics dimension.

  20. Fusion Physics Toward ITER

    NASA Astrophysics Data System (ADS)

    Stambaugh, R. D.

    2006-04-01

    Stars are powered by fusion, the energy released by fusing together light nuclei, using gravitational confinement of plasma. Fusion on earth will be done in a 100 million degree plasma made of deuterium and tritium and confined by magnetic fields or inertia. The worldwide fusion research community will construct ITER, the first experiment that will burn a DT plasma by copious fusion reactions. ITER's nominal goal is to create 500 MW of fusion power. An energy gain of 10 will mean the plasma is dominantly self-heated by the fusion-produced alpha particles. ITER's all superconducting magnet technology and steady-state heat removal technology will enable nominal 400 s pulses to allow the study of burning plasmas on the longest intrinsic timescale of the confined plasma - diffusive redistribution of the electrical currents in the plasma. The advances in magnetic confinement physics that have led to this opportunity will be described, as well as the research opportunities afforded by ITER. The physics of confining stable plasmas and heating them will produce the high gain state in ITER. Sustained burn will come from the physics of controlling currents in plasmas and how the hot plasma is interfaced to its room temperature surroundings. ITER will provide our first experience with how fusion plasma self-heating will profoundly affect the complex, interlinked physical processes that occur in confined plasmas.

  1. Advanced Multifunctional Properties of Aligned Carbon Nanotube-Epoxy Composites from Carbon Nanotube Aerogel Method

    NASA Astrophysics Data System (ADS)

    Tran, Thang; Liu, Peng; Fan, Zeng; Ngern, Nigel; Duong, Hai

    2015-03-01

    Unlike previous methods of making carbon nanotube (CNT) thin films, aligned CNT thin films in this work are synthesized directly from CNT aerogels in a CVD process. CH4/H2/He gases and ferrocene/thiophene catalysts are mixed and reacted in the reactor at 1200 °C to form CNT aerogel socks. By pulling out the socks with a metal rod, CNT thin films with 15-nm diameter MWNTs are aligned and produced continuously at a speed of a few meters per minute. The number of the aligned CNT thin film layers/ thickness can also be controlled well. The as-synthesized aligned CNT films are further condensed by acetone spray and post-treated by UV light. The aligned CNT films without any above post-treatment have a high electrical conductivity of 400S/cm. We also develop aligned CNT-epoxy composites by infiltrating epoxy into the above aligned CNT thin films using Vacuum Assisted Resin Transfer Molding (VARTM) method. Our cost-effective fabrication method of the aligned CNT films is more advanced for developing the composites having CNT orientation control. The mechanical, electrical and optical properties of the aligned CNT epoxy composites are measured. About 2% of the aligned CNTs can enhance significantly the electrical conductivity and hardness of aligned CNT-epoxy composite films. Effects of morphologies, volume fraction, and alignment of the CNTs on the advanced multifunctional properties of the aligned CNT-epoxy composites are also quantified.

  2. Variations in the corneal surface temperature with contact lens wear.

    PubMed

    Ooi, E H; Ng, E Y K; Purslow, C; Acharya, R

    2007-05-01

    This paper presents the two-dimensional simulation of heat propagation in the human eye model during contact lens wear with finite element analysis. Three types of contact lens are studied: Lotrafilcon A, Balafilcon A, and Etafilcon A. The models are solved for both steady and transient solutions. The corneal surface temperature during contact lens wear is found to decrease (average, 0.52 +/- 0.05 degrees C compared with a bare cornea for all lens types). A contact lens with a higher water content has a lower steady state temperature than a contact lens with a lower water content does. Various initial temperatures for the contact lens are found to affect the first 400 s of the temperature variation. When the initial temperature is lower than the corneal temperature, a reduction in temperature is observed during contact lens insertion while the opposite is observed when the initial temperature is higher than the corneal temperature. The increase in evaporation rate when a contact lens is worn increases the cooling effect on the ocular surface. This is suggested to be the cause of lower corneal surface temperature when wearing a contact lens.

  3. Correlation of thrombosis growth rate to pathological wall shear rate during platelet accumulation.

    PubMed

    Bark, David L; Para, Andrea N; Ku, David N

    2012-10-01

    Local hemodynamics may strongly influence atherothrombosis, which can lead to acute myocardial infarction and stroke. The relationship between hemodynamics and thrombosis during platelet accumulation was studied through an in vitro flow system consisting of a stenosis. Specifically, wall shear rates (WSR) ranging from 0 to 100,000 s(-1) were ascertained through computations and compared with thrombus growth rates found by image analysis for over 5,000 individual observation points per experiment. A positive correlation (P < 0.0001) was found between thrombus accumulation rates and WSR up to 6,000 s(-1), with a decrease in growth rates at WSR >6,000 s(-1) (P < 0.0001). Furthermore, growth rates at pathological shear rates were found to be two to four times greater than for physiological arterial shear rates below 400 s(-1). Platelets did not accumulate for the first minute of perfusion. The initial lag time, before discernible thrombus growth could be found, diminished with shear (P < 0.0001). These studies show the quantitative increase in thrombus growth rates with very high shear rates in stenoses onto a collagen substrate. PMID:22539078

  4. Evaluation of polymerization shrinkage of dental composites by an optical method.

    PubMed

    Weig, K M; Magalhães Filho, T R; Costa Neto, C A; Costa, M F

    2015-02-01

    This study proposes an alternative methodology for evaluating polymerization shrinkage of dental composites using an advanced video extensometer (AVE) system. This equipment measures the displacement between two points drawn on a tooth's wall without requiring physical contact with the tooth. By doing so, the polymerization process was monitored by the cusp deflection. This technique was used in human and bovine teeth, where the cavities were prepared under controlled conditions so that the volume of the composite used was the same in both types of teeth. After the cavity preparation, the specimens were acid etched, washed and dried, and then the adhesive was applied and polymerized. The composite was then inserted into the cavity. Polymerization was performed with two different light polymerizing units (LD Max and Optilight Max - Gnatus do Brasil), and the displacement curve of the tooth cusp was recorded for a period of 400 s. After a statistical analysis, it was concluded that the technique was capable of evaluating shrinkage by the deflection from the cusps and that the human and bovine teeth do not react in a similar manner towards the polymerization shrinkage of composites.

  5. An Evolutionary S-wave Model of the Earth Upper Mantle and Transition Zone

    NASA Astrophysics Data System (ADS)

    Debayle, E.; Dubuffet, F.; Durand, S.

    2015-12-01

    We present 3D2015_03Sv, an evolutionary S-wave model of the upper mantle. At the time of submitting this abstract, the model is based on the waveform modeling of most Rayleigh waves recorded between 1976 and March 2015, and includes 1,330,210 fundamental and higher mode Rayleigh waveforms analyzed at periods between 40 and 400 s. The use of approximate forward theory and modeling allows updating the model with new data on a regular basis, a few days after the publication of the monthly centroid moment tensor (CMT) catalog issued at the Lamont-Doherty Earth Observatory of Columbia University. 3D2015_03Sv contains azimuthal anisotropy and achieves a lateral resolution of ~600 km in the upper mantle. Comparison with other seismic models shows that in the uppermost 200 km, the use of massive datasets with large redundancies allows to average errors, so that it is possible to build models that are consistent up to degree 60. In the transition zone, the number of data decreases and the effect of modeling choices is important. The most recent seismic models agree up to degree 15, which represents an improvement compared to the previous generation of models.

  6. Magnetic-confinement fusion

    NASA Astrophysics Data System (ADS)

    Ongena, J.; Koch, R.; Wolf, R.; Zohm, H.

    2016-05-01

    Our modern society requires environmentally friendly solutions for energy production. Energy can be released not only from the fission of heavy nuclei but also from the fusion of light nuclei. Nuclear fusion is an important option for a clean and safe solution for our long-term energy needs. The extremely high temperatures required for the fusion reaction are routinely realized in several magnetic-fusion machines. Since the early 1990s, up to 16 MW of fusion power has been released in pulses of a few seconds, corresponding to a power multiplication close to break-even. Our understanding of the very complex behaviour of a magnetized plasma at temperatures between 150 and 200 million °C surrounded by cold walls has also advanced substantially. This steady progress has resulted in the construction of ITER, a fusion device with a planned fusion power output of 500 MW in pulses of 400 s. ITER should provide answers to remaining important questions on the integration of physics and technology, through a full-size demonstration of a tenfold power multiplication, and on nuclear safety aspects. Here we review the basic physics underlying magnetic fusion: past achievements, present efforts and the prospects for future production of electrical energy. We also discuss questions related to the safety, waste management and decommissioning of a future fusion power plant.

  7. Facile production of thermoelectric bismuth telluride thick films in the presence of polyvinyl alcohol.

    PubMed

    Lei, C; Burton, M R; Nandhakumar, I S

    2016-06-01

    Bismuth telluride is currently the best performing thermoelectric material for room temperature operations in commercial thermoelectric devices. We report the reproducible and facile production of 600 micron thick bismuth telluride (Bi2Te3) layers by low cost and room temperature pulsed and potentiostatic electrodeposition from a solution containing bismuth and tellurium dioxide in 2 M nitric acid onto nickel in the presence of polyvinyl alcohol (PVA). This was added to the electrolyte to promote thick layer formation and its effect on the structure, morphology and composition of the electrodeposits was investigated by SEM and EDX. Well adherent, uniform, compact and stoichiometric n-type Bi2Te3 films with a high Seebeck coefficient of up to -200 μV K(-1) and a high electrical conductivity of up to 400 S cm(-1) resulting in a power factor of 1.6 × 10(-3) W m(-1) K(-2) at film growth rates of 100 μm h(-1) for potentiostatic electrodeposition were obtained. The films also exhibited a well defined hexagonal structure as determined by XRD.

  8. Kinetics of hot-gas desulfurization sorbents for transport reactors

    SciTech Connect

    K.C. Kwon

    2000-01-01

    Hot-gas desulfurization for the integrated gasification combined cycle (IGCC) process has been investigated by many researchers to remove effectively hydrogen sulfide with various metal oxide sorbents at elevated temperatures. Various metal oxide sorbents are formulated with metal oxides such as Fe, Co, Zn, and Ti. Initial reaction kinetics of formulated sorbents with hydrogen sulfide is studied in the presence of various amounts of moisture and hydrogen at various reaction temperatures. The objectives of this research are to study initial reaction kinetics for a sorbent-hydrogen sulfide heterogeneous reaction system, to investigate effects of concentrations of hydrogen sulfide, hydrogen, and moisture on dynamic absorption of H{sub 2}S into sorbents, to understand effects of space time of reaction gas mixtures on initial reaction kinetics of the sorbent-hydrogen sulfide system, and to evaluate effects of temperature and sorbent amounts on dynamic absorption of H{sub 2}S into sorbents. Experimental data on initial reaction kinetics of hydrogen sulfide with metal oxide sorbents were obtained with a 0.83-cm{sup 3} differential reactor. The reactivity of MCRH-67 sorbent and AHI-1 was examined. These sorbents were obtained from the Research Triangle Institute (RTI). The sorbents in the form of 70 {micro}m particles are reacted with 1,000--4,000 ppm hydrogen sulfide at 450--600 C. The range of space time of reaction gas mixtures is 0.03--0.09 s. The range of reaction duration is 4--14,400 s.

  9. Immobilization of chromate in hyperalkaline waste streams by green rusts and zero-valent iron.

    PubMed

    Rogers, Christine M; Burke, Ian T; Ahmed, Imad A M; Shaw, Samuel

    2014-01-01

    Zero-valent iron (ZVI) and green rusts can be used as reductants to convert chromium from soluble, highly toxic Cr(VI) to insoluble Cr(III). This study compared the reduction rates of Cr(VI) by ZVI and two carbonate green rust phases in alkaline/hyperalkaline solutions. Batch experiments were carried out with synthetic chromate solutions at pH 7.7-12.3 and a chromite ore processing residue (COPR) leachate (pH approximately 12.2). Green rust removes chromate from high pH solutions (pH 10-12.5) very rapidly (<400 s). Chromate reduction rates for both green rust phases were consistently higher than for ZVI throughout the pH range studied; the surface area normalized rate constants were two orders of magnitude higher in the COPR leachate solution at pH 12.2. The performances of both green rusts were unaffected by changes in pH. In contrast, ZVI exhibited a marked decline in reduction rate with increasing pH to become almost ineffective above pH12. PMID:24600891

  10. Out-of-equilibrium dynamics in the cytoskeleton of the living cell

    NASA Astrophysics Data System (ADS)

    Lenormand, Guillaume; Bursac, Predrag; Butler, James P.; Fredberg, Jeffrey J.

    2007-10-01

    We report here measurements of rheological properties of the human airway smooth muscle cell using forced nanoscale motions of Arg-Gly-Asp RGD-coated microbeads tightly bound to the cytoskeleton. With changes of forcing amplitude, the storage modulus showed small but systematic nonlinearities, especially after treatment with a contractile agonist. In a dose-dependent manner, a large oscillatory shear applied from a few seconds up to 400s caused the cytoskeleton matrix to soften, a behavior comparable to physical rejuvenation observed in certain inert soft materials; the stiffness remained constant for as long as the large oscillatory shear was maintained, but suddenly fell with shear cessation. Stiffness then followed a slow scale-free recovery, a phenomenon comparable to physical aging. However, acetylated low-density lipoprotein acLDL-coated microbeads, which connect mainly to scavenger receptors, did not show similar out-of-equilibrium behaviors. Taken together, these data demonstrate in the cytoskeleton of the living cell behaviors with all the same signatures as that of soft inert condensed systems. This unexpected intersection of condensed matter physics and cytoskeletal biology suggests that trapping, intermittency, and approach to kinetic arrest represent central mesoscale features linking underlying molecular events to integrative cellular functions.

  11. Immobilization of chromate in hyperalkaline waste streams by green rusts and zero-valent iron.

    PubMed

    Rogers, Christine M; Burke, Ian T; Ahmed, Imad A M; Shaw, Samuel

    2014-01-01

    Zero-valent iron (ZVI) and green rusts can be used as reductants to convert chromium from soluble, highly toxic Cr(VI) to insoluble Cr(III). This study compared the reduction rates of Cr(VI) by ZVI and two carbonate green rust phases in alkaline/hyperalkaline solutions. Batch experiments were carried out with synthetic chromate solutions at pH 7.7-12.3 and a chromite ore processing residue (COPR) leachate (pH approximately 12.2). Green rust removes chromate from high pH solutions (pH 10-12.5) very rapidly (<400 s). Chromate reduction rates for both green rust phases were consistently higher than for ZVI throughout the pH range studied; the surface area normalized rate constants were two orders of magnitude higher in the COPR leachate solution at pH 12.2. The performances of both green rusts were unaffected by changes in pH. In contrast, ZVI exhibited a marked decline in reduction rate with increasing pH to become almost ineffective above pH12.

  12. Different mechanisms for role relations versus verb-action congruence effects: evidence from ERPs in picture-sentence verification.

    PubMed

    Knoeferle, Pia; Urbach, Thomas P; Kutas, Marta

    2014-10-01

    Extant accounts of visually situated language processing do make general predictions about visual context effects on incremental sentence comprehension; these, however, are not sufficiently detailed to accommodate potentially different visual context effects (such as a scene-sentence mismatch based on actions versus thematic role relations, e.g., (Altmann & Kamide, 2007; Knoeferle & Crocker, 2007; Taylor & Zwaan, 2008; Zwaan & Radvansky, 1998)). To provide additional data for theory testing and development, we collected event-related brain potentials (ERPs) as participants read a subject-verb-object sentence (500 ms SOA in Experiment 1 and 300 ms SOA in Experiment 2), and post-sentence verification times indicating whether or not the verb and/or the thematic role relations matched a preceding picture (depicting two participants engaged in an action). Though incrementally processed, these two types of mismatch yielded different ERP effects. Role-relation mismatch effects emerged at the subject noun as anterior negativities to the mismatching noun, preceding action mismatch effects manifest as centro-parietal N400s greater to the mismatching verb, regardless of SOAs. These two types of mismatch manipulations also yielded different effects post-verbally, correlated differently with a participant's mean accuracy, verbal working memory and visual-spatial scores, and differed in their interactions with SOA. Taken together these results clearly implicate more than a single mismatch mechanism for extant accounts of picture-sentence processing to accommodate. PMID:25216075

  13. NASA PS400: A New Temperature Solid Lubricant Coating for High Temperature Wear Applications

    NASA Technical Reports Server (NTRS)

    DellaCorte, C.; Edmonds, B. J.

    2009-01-01

    A new solid lubricant coating, NASA PS400, has been developed for high temperature tribological applications. This plasma sprayed coating is a variant of the patented PS304 coating and has been formulated to provide higher density, smoother surface finish and better dimensional stability than PS304. PS400 is comprised of a nickel-molybdenum binder that provides strength, creep resistance and extreme oxidative and dimensional stability. Chromium oxide, silver and barium-calcium fluoride eutectic are added to the binder to form PS400.Tribological properties were evaluated with a pin-on-disk test rig in sliding contact to 650 C. Coating material samples were exposed to air, argon and vacuum at 760 C followed by cross section microscopic analysis to assess microstructure stability. Oil-Free microturbine engine hot section foil bearing tests were undertaken to assess PS400 s suitability for hot foil gas bearing applications. The preliminary results indicate that PS400 exhibits tribological characteristics comparable to the PS304 coating but with enhanced creep resistance and dimensional stability suitable for demanding, dynamic applications.

  14. Roles of cell and microvillus deformation and receptor-ligand binding kinetics in cell rolling.

    PubMed

    Pawar, Parag; Jadhav, Sameer; Eggleton, Charles D; Konstantopoulos, Konstantinos

    2008-10-01

    Polymorphonuclear leukocyte (PMN) recruitment to sites of inflammation is initiated by selectin-mediated PMN tethering and rolling on activated endothelium under flow. Cell rolling is modulated by bulk cell deformation (mesoscale), microvillus deformability (microscale), and receptor-ligand binding kinetics (nanoscale). Selectin-ligand bonds exhibit a catch-slip bond behavior, and their dissociation is governed not only by the force but also by the force history. Whereas previous theoretical models have studied the significance of these three "length scales" in isolation, how their interplay affects cell rolling has yet to be resolved. We therefore developed a three-dimensional computational model that integrates the aforementioned length scales to delineate their relative contributions to PMN rolling. Our simulations predict that the catch-slip bond behavior and to a lesser extent bulk cell deformation are responsible for the shear threshold phenomenon. Cells bearing deformable rather than rigid microvilli roll slower only at high P-selectin site densities and elevated levels of shear (>or=400 s(-1)). The more compliant cells (membrane stiffness=1.2 dyn/cm) rolled slower than cells with a membrane stiffness of 3.0 dyn/cm at shear rates >50 s(-1). In summary, our model demonstrates that cell rolling over a ligand-coated surface is a highly coordinated process characterized by a complex interplay between forces acting on three distinct length scales.

  15. Tooth bleaching using three laser systems, halogen-light unit, and chemical action agents

    NASA Astrophysics Data System (ADS)

    Dostalova, Tatjana; Jelinkova, Helena; Housova, Devana; Sulc, Jan; Nemec, Michal; Koranda, Petr; Miyagi, Mitsunobu; Shi, Yi-Wei; Matsuura, Yuji

    2004-09-01

    μThe study describes the preclinical experience with laser-activated bleaching agent for discolored teeth. Extracted human upper central incisors were selected, and in the bleaching experiment 35% hydrogen peroxide was used. Three various laser systems and halogen-light unit for activation of the bleaching agent were applied. They were Alexandrite laser (wavelength 750 nm and 375 nm - SHG), Nd:YAG laser (wavelength 1.064 m), and Er:YAG laser (wavelength 2.94 μm). The halogen-light unit was used in a standard regime. The enamel surface was analyzed in the scanning electron microscope. The method of chemical oxidation results in a 2-3 shade change in one treatment. The halogen-light units produced the same effect with shorter time of bleaching process (from 630 s to 300 s). The Alexandrite laser (750 nm) and bleaching agent helped to reach the desired color shade after a shorter time (400 s). Alexandrite laser (375 nm) and Nd:YAG laser had no effect on the longevity of the process of bleaching. Overheating of the chemical bleaching agent was visible after Er:YAG laser activation (195 s). Slight surface modification after bleaching process was detected in SEM.

  16. Language effects in second-language learners: A longitudinal electrophysiological study of spanish classroom learning.

    PubMed

    Soskey, Laura; Holcomb, Phillip J; Midgley, Katherine J

    2016-09-01

    How do the neural mechanisms involved in word recognition evolve over the course of word learning in adult learners of a new second language? The current study sought to closely track language effects, which are differences in electrophysiological indices of word processing between one's native and second languages, in beginning university learners over the course of a single semester of learning. Monolingual L1 English-speakers enrolled in introductory Spanish were first trained on a list of 228 Spanish words chosen from the vocabulary to be learned in class. Behavioral data from the training session and the following experimental sessions spaced over the course of the semester showed expected learning effects. In the three laboratory sessions participants read words in three lists (English, Spanish and mixed) while performing a go/no-go lexical decision task in which event-related potentials (ERPs) were recorded. As observed in previous studies there were ERP language effects with larger N400s to native than second language words. Importantly, this difference declined over the course of L2 learning with N400 amplitude increasing for new second language words. These results suggest that even over a single semester of learning that new second language words are rapidly incorporated into the word recognition system and begin to take on lexical and semantic properties similar to native language words. Moreover, the results suggest that electrophysiological measures can be used as sensitive measures for tracking the acquisition of new linguistic knowledge. PMID:27233808

  17. Effect of nitridation surface treatment on silicon (1 1 1) substrate for the growth of high quality single-crystalline GaN hetero-epitaxy layer by MOCVD

    NASA Astrophysics Data System (ADS)

    Rahman, Mohd Nazri Abd.; Yusuf, Yusnizam; Mansor, Mazwan; Shuhaimi, Ahmad

    2016-01-01

    A single-crystalline with high quality of gallium nitride epilayers was grown on silicon (1 1 1) substrate by metal organic chemical vapor deposition. The process of nitridation surface treatment was accomplished on silicon (1 1 1) substrate by flowing the ammonia gaseous. Then, it was followed by a thin aluminum nitride nucleation layer, aluminum nitride/gallium nitride multi-layer and a thick gallium nitride epilayer. The influence of in situ nitridation surface treatment on the crystallinity quality of gallium nitride epilayers was studied by varying the nitridation times at 40, 220 and 400 s, respectively. It was shown that the nitridation times greatly affect the structural properties of the grown top gallium nitride epilayer on silicon (1 1 1) substrate. In the (0 0 0 2) and (1 0 1 bar 2) X-ray rocking curve analysis, a narrower value of full width at half-maximum has been obtained as the nitridation time increased. This is signifying the reduction of dislocation density in the gallium nitride epilayer. This result was supported by the value of bowing and root mean square roughness measured by surface profilometer and atomic force microscopy. Furthermore, a crack-free gallium nitride surface with an abrupt cross-sectional structure that observed using field effect scanning electron microscopy was also been obtained. The phi-scan curve of asymmetric gallium nitride proved the top gallium nitride epilayer exhibited a single-crystalline structure.

  18. Non-Neutral Plasma Confinement In A Cusp-Trap And Possible Application To Anti-Hydrogen Beam Generation

    SciTech Connect

    Mohri, Akihiro; Kanai, Yasuyuki; Nakai, Yoichi; Yamazaki, Yasunori

    2005-10-19

    A new scheme for synthesizing antihydrogen by trapping positrons and antiprotons in a field consisting of a magnetic quadrupole and an electric octupole (cusp -trap) is now under investigation. The total electric field of the octupole with the space charge of a nonneutral plasma composed of particles of the same sign of charge, i.e., positrons or mixture of electrons and antiprotons, is expected to form a potential well for particles of the opposite sign of charge. Particles trapped in the well are mixed with the present dense particles, where positrons and antiprotons will combine to produce antihydrogen atoms. A considerable fraction of antihydrogen atoms in low-field seeking states will be transported outside as a beam.Experiments on electron confinement in the cusp-trap were carried out in a strong magnetic quadrupole (3.8T at the maximum on the axis). The confinement time reached 400s for the trapped electron number N0= 3.6x107. The time decreased with N0 but it was still about 100s for N0= 1.6x108.An electron plasma initially formed around the zero-field point rapidly expanded and settled down onto a quasi-stable state. Cross-sectional density profiles had shapes like a high volcano with a big crater. Analysis of the density profile shows that a potential well for oppositely charged particles (positive ions in this case) is probably formed inside the trapped electrons.

  19. Autoclassification of the Variable 3XMM Sources Using the Random Forest Machine Learning Algorithm

    NASA Astrophysics Data System (ADS)

    Farrell, Sean A.; Murphy, Tara; Lo, Kitty K.

    2015-11-01

    In the current era of large surveys and massive data sets, autoclassification of astrophysical sources using intelligent algorithms is becoming increasingly important. In this paper we present the catalog of variable sources in the Third XMM-Newton Serendipitous Source catalog (3XMM) autoclassified using the Random Forest machine learning algorithm. We used a sample of manually classified variable sources from the second data release of the XMM-Newton catalogs (2XMMi-DR2) to train the classifier, obtaining an accuracy of ∼92%. We also evaluated the effectiveness of identifying spurious detections using a sample of spurious sources, achieving an accuracy of ∼95%. Manual investigation of a random sample of classified sources confirmed these accuracy levels and showed that the Random Forest machine learning algorithm is highly effective at automatically classifying 3XMM sources. Here we present the catalog of classified 3XMM variable sources. We also present three previously unidentified unusual sources that were flagged as outlier sources by the algorithm: a new candidate supergiant fast X-ray transient, a 400 s X-ray pulsar, and an eclipsing 5 hr binary system coincident with a known Cepheid.

  20. Intermittent heat instabilities in an air plume

    NASA Astrophysics Data System (ADS)

    Le Mouël, Jean-Louis; Kossobokov, Vladimir G.; Perrier, Frederic; Morat, Pierre

    2016-08-01

    We report the results of heating experiments carried out in an abandoned limestone quarry close to Paris, in an isolated room of a volume of about 400 m3. A heat source made of a metallic resistor of power 100 W was installed on the floor of the room, at distance from the walls. High-quality temperature sensors, with a response time of 20 s, were fixed on a 2 m long bar. In a series of 24 h heating experiments the bar had been set up horizontally at different heights or vertically along the axis of the plume to record changes in temperature distribution with a sampling time varying from 20 to 120 s. When taken in averages over 24 h, the temperatures present the classical shape of steady-state plumes, as described by classical models. On the contrary, the temperature time series show a rich dynamic plume flow with intermittent trains of oscillations, spatially coherent, of large amplitude and a period around 400 s, separated by intervals of relative quiescence whose duration can reach several hours. To our knowledge, no specific theory is available to explain this behavior, which appears to be a chaotic interaction between a turbulent plume and a stratified environment. The observed behavior, with first-order factorization of a smooth spatial function with a global temporal intermittent function, could be a universal feature of some turbulent plumes in geophysical environments.

  1. Densest packings of hard spheres in a cylinder

    NASA Astrophysics Data System (ADS)

    Fu, Lin; Steinhardt, William; Zhao, Hao; Socolar, Joshua; Charbonneau, Patrick

    Densely packing hard spheres (HS) within a cylinder is remarkably complex. Little is known about the densest achievable packings when the cylinder diameter, D, is larger than 2.85 times the sphere diameter, s. Here, we extend the identification of the densest packings up to D = 4.00s by adapting Torquato-Jiao's adaptive-shrinking-cell formulation and sequential-linear-programming technique to this geometry. We identify 17 new structures, almost all of them chiral. Beyond D, approx2.85s , most of the structures consist of an outer shell and of an inner core that compete for being close packed. In some cases the shell adopts a periodic configuration that is optimal and the stacking of core spheres within it is quasiperiodic, while in other cases a direct interplay between the two layers is observed. For some packings the very distinction between the core and shell vanishes, which results in exotic geometries, including some that are a three-dimensional extension of packing hard disks in a circle. In order to connect our results with experiments on comparable systems, we also consider the ease with which these structures assemble. Using kinetic Monte Carlo simulations, we find that some of the structures promtply assemble while others simply do not.

  2. Spectral components of laser Doppler flowmetry signals recorded in healthy and type 1 diabetic subjects at rest and during a local and progressive cutaneous pressure application: scalogram analyses

    NASA Astrophysics Data System (ADS)

    Humeau, Anne; Koïtka, Audrey; Abraham, Pierre; Saumet, Jean-Louis; L'Huillier, Jean-Pierre

    2004-09-01

    A significant transient increase in laser Doppler flowmetry (LDF) signals is observed in response to a local and progressive cutaneous pressure application in healthy subjects. This reflex may be impaired in diabetic patients. The work presents a signal processing providing the clarification of this phenomenon. Scalogram analyses of LDF signals recorded at rest and during a local and progressive cutaneous pressure application are performed on healthy and type 1 diabetic subjects. Three frequency bands, corresponding to myogenic, neurogenic and endothelial related metabolic activities, are studied. The results show that, at rest, the scalogram energy of each frequency band is significantly lower for diabetic patients than for healthy subjects, but the scalogram relative energies do not show any statistical difference between the two groups. Moreover, the neurogenic and endothelial related metabolic activities are significantly higher during the progressive pressure than at rest, in healthy and diabetic subjects. However, the relative contribution of the endothelial related metabolic activity is significantly higher during the progressive pressure than at rest, in the interval 200-400 s following the beginning of the pressure application, but only for healthy subjects. These results may improve knowledge on cutaneous microvascular responses to injuries or local pressures initiating diabetic complications.

  3. Searching for a Long Cosmic String through the Gravitational Lensing Effect

    NASA Astrophysics Data System (ADS)

    Shirasaki, Y.; Matsuzaki, Ei-ichi; Mizumoto, Yoshihiko; Kakimoto, Fumio; Ogio, Syoichi; Yasuda, Naoki; Tanaka, Masahiro; Yahagi, Hideki; Nagashima, Masahiro; Kosugi, George

    2003-07-01

    It has been suggested that cosmic strings produced at a phase transition in the early universe can be the origin of the extremely high energy cosmic rays (EHCR) observed by AGASA above 1020 eV. superheavy cosmic strings with linear mass density of 1022 g/cm can be indirectly observed through the gravitational lensing effect the distant galaxies. The lensing effect by a long straight object can be characterized by a line of double galaxies or quasars with angular separation of about 5 arcsec. We have searched for aligned double objects from the archived data taken by the Subaru Prime Fo cus Camera (Suprime-Cam). The SuprimeCam has a great advantage in observing the wide field of view (30×30 arcmin2 ) with high sensitivity (R<26 400s exposure), so it is suitable for this research. In this paper, we describe the result of simulation study for developing the method of searching the objects lensed by cosmic strings, and present the observational result obtained by this method.

  4. Evaluation of Incoherent Interface Strength of Solid-State-Bonded Ti64/Stainless Steel Under Dynamic Impact Loading

    NASA Astrophysics Data System (ADS)

    Verma, Devendra; Singh, Jogender; Varma, Amit H.; Tomar, Vikas

    2015-08-01

    Ti/steel interfaces are produced using field-assisted sintering technology, a technique known to bring about full consolidation of materials using much lower sintering temperatures and durations. The interface thickness is verified using the energy-dispersive x-ray analysis exhibiting the extent of diffusion in interface regions. The interface mechanical strength is characterized using dynamic indentation experiments at strain rates approaching 400 s-1. The experiments were conducted on the interfaces within the spatial error tolerance of less than 3 µm. The measurements of dynamic hardness values, strain rates, and plastic-residual depths were correlated to show the relation of interface mechanical strength with the bulk-phase mechanical strength properties of Ti and steel. The Johnson-Cook model is fitted to the obtained interface normal stress-normal strain data based on the nanoimpact experiments. The coefficient of restitution in the mechanical loading and its dependence on the interface dynamic hardness and interface impact velocity validate the experimental results. The results show that interfacial properties are affected by the rate of loading and are largely dependent upon the interface structural inhomogeneity.

  5. Optimizing the Face Paradigm of BCI System by Modified Mismatch Negative Paradigm

    PubMed Central

    Zhou, Sijie; Jin, Jing; Daly, Ian; Wang, Xingyu; Cichocki, Andrzej

    2016-01-01

    Many recent studies have focused on improving the performance of event-related potential (ERP) based brain computer interfaces (BCIs). The use of a face pattern has been shown to obtain high classification accuracies and information transfer rates (ITRs) by evoking discriminative ERPs (N200 and N400) in addition to P300 potentials. Recently, it has been proved that the performance of traditional P300-based BCIs could be improved through a modification of the mismatch pattern. In this paper, a mismatch inverted face pattern (MIF-pattern) was presented to improve the performance of the inverted face pattern (IF-pattern), one of the state of the art patterns used in visual-based BCI systems. Ten subjects attended in this experiment. The result showed that the mismatch inverted face pattern could evoke significantly larger vertex positive potentials (p < 0.05) and N400s (p < 0.05) compared to the inverted face pattern. The classification accuracy (mean accuracy is 99.58%) and ITRs (mean bit rate is 27.88 bit/min) of the mismatch inverted face pattern was significantly higher than that of the inverted face pattern (p < 0.05). PMID:27774046

  6. Native-like brain processing of syntax can be attained by university foreign language learners.

    PubMed

    Bowden, Harriet Wood; Steinhauer, Karsten; Sanz, Cristina; Ullman, Michael T

    2013-11-01

    Using event-related potentials (ERPs), we examined the neurocognition of late-learned second language (L2) Spanish in two groups of typical university foreign-language learners (as compared to native (L1) speakers): one group with only one year of college classroom experience, and low-intermediate proficiency (L2 Low), and another group with over three years of college classroom experience as well as 1-2 semesters of immersion experience abroad, and advanced proficiency (L2 Advanced). Semantic violations elicited N400s in all three groups, whereas syntactic word-order violations elicited LAN/P600 responses in the L1 and L2 Advanced groups, but not the L2 Low group. Indeed, the LAN and P600 responses were statistically indistinguishable between the L1 and L2 Advanced groups. The results support and extend previous findings. Consistent with previous research, the results suggest that L2 semantic processing always depends on L1-like neurocognitive mechanisms, whereas L2 syntactic processing initially differs from L1, but can shift to native-like processes with sufficient proficiency or exposure, and perhaps with immersion experience in particular. The findings further demonstrate that substantial native-like brain processing of syntax can be achieved even by typical university foreign-language learners.

  7. Language effects in second-language learners: A longitudinal electrophysiological study of spanish classroom learning.

    PubMed

    Soskey, Laura; Holcomb, Phillip J; Midgley, Katherine J

    2016-09-01

    How do the neural mechanisms involved in word recognition evolve over the course of word learning in adult learners of a new second language? The current study sought to closely track language effects, which are differences in electrophysiological indices of word processing between one's native and second languages, in beginning university learners over the course of a single semester of learning. Monolingual L1 English-speakers enrolled in introductory Spanish were first trained on a list of 228 Spanish words chosen from the vocabulary to be learned in class. Behavioral data from the training session and the following experimental sessions spaced over the course of the semester showed expected learning effects. In the three laboratory sessions participants read words in three lists (English, Spanish and mixed) while performing a go/no-go lexical decision task in which event-related potentials (ERPs) were recorded. As observed in previous studies there were ERP language effects with larger N400s to native than second language words. Importantly, this difference declined over the course of L2 learning with N400 amplitude increasing for new second language words. These results suggest that even over a single semester of learning that new second language words are rapidly incorporated into the word recognition system and begin to take on lexical and semantic properties similar to native language words. Moreover, the results suggest that electrophysiological measures can be used as sensitive measures for tracking the acquisition of new linguistic knowledge.

  8. Stuttering and Natural Speech Processing of Semantic and Syntactic Constraints on Verbs

    PubMed Central

    Weber-Fox, Christine; Hampton, Amanda

    2009-01-01

    Purpose Previous findings from event-related brain potentials (ERPs) indicate that adults who stutter (AWS) exhibit processing differences for visually presented linguistic information. This study explores how neural activations for AWS may differ for a linguistic task that does not require preparation for overt articulation and/or engage the articulatory loop for silent speech. Method Syntactic and semantic processing constraints were examined in AWS and adults who are normally fluent (AWNF) by assessing their behavioral performance and ERPs in a natural speech listening task. Results AWS performed similarly to AWNF in identifying verb-agreement violations and semantic anomalies, but ERPs elicited by syntactic and semantic constraints indicated atypical neural functions for AWS. ERPs of the AWNF displayed an expected N400 for reduced semantic expectations and a typical P600 for verb-agreement violations. In contrast, both N400s and P600s for the semantic and verb-agreement conditions were observed in the ERPs of the AWS. Conclusions The findings suggest that AWS may engage semantic-syntactic mechanisms more generally for semantic and syntactic processing. These findings converge with earlier studies using visual stimuli to indicate that, while linguistic abilities are normal in AWS, underlying brain activity mediating some aspects of language processing may function differently. PMID:18664690

  9. ERP evidence for conceptual mappings and comparison processes during the comprehension of conventional and novel metaphors.

    PubMed

    Lai, Vicky Tzuyin; Curran, Tim

    2013-12-01

    Cognitive linguists suggest that understanding metaphors requires activation of conceptual mappings between the involved concepts. We tested whether mappings are indeed in use during metaphor comprehension, and what mapping means as a cognitive process with Event-Related Potentials. Participants read literal, conventional metaphorical, novel metaphorical, and anomalous target sentences preceded by primes with related or unrelated mappings. Experiment 1 used sentence-primes to activate related mappings, and Experiment 2 used simile-primes to induce comparison thinking. In the unprimed conditions of both experiments, metaphors elicited N400s more negative than the literals. In Experiment 1, related sentence-primes reduced the metaphor-literal N400 difference in conventional, but not in novel metaphors. In Experiment 2, related simile-primes reduced the metaphor-literal N400 difference in novel, but not clearly in conventional metaphors. We suggest that mapping as a process occurs in metaphors, and the ways in which it can be facilitated by comparison differ between conventional and novel metaphors.

  10. Radio-Frequency Superimposed Direct Current Magnetron Sputtered Ga:ZnO Transparent Conducting Thin Films

    SciTech Connect

    Sigdel, A. K.; Ndione, P. F.; Perkins, J. D.; Gennett, T.; van Hest, M. F. A. M.; Shaheen, S. E.; Ginley, D. S.; Berry, J. J.

    2012-05-01

    The utilization of radio-frequency (RF) superimposed direct-current (DC) magnetron sputtering deposition on the properties of gallium doped ZnO (GZO) based transparent conducting oxides has been examined. The GZO films were deposited using 76.2 mm diameter ZnO:Ga{sub 2}O{sub 3} (5 at. % Ga vs. Zn) ceramic oxide target on heated non-alkaline glass substrates by varying total power from 60 W to 120 W in steps of 20 W and at various power ratios of RF to DC changing from 0 to 1 in steps of 0.25. The GZO thin films grown with pure DC, mixed approach, and pure RF resulted in conductivities of 2200 {+-} 200 S/cm, 3920 {+-} 600 S/cm, and 3610 {+-} 400 S/cm, respectively. X-ray diffraction showed all films have wurtzite ZnO structure with the c-axis oriented perpendicular to the substrate. The films grown with increasing RF portion of the total power resulted in the improvement of crystallographic texture with smaller full-width half maximum in {chi} and broadening of optical gap with increased carrier concentration via more efficient doping. Independent of the total sputtering power, all films grown with 50% or higher RF power portion resulted in high mobility ({approx}28 {+-} 1 cm{sup 2}/Vs), consistent with observed improvements in crystallographic texture. All films showed optical transmittance of {approx}90% in the visible range.

  11. Radio-frequency superimposed direct current magnetron sputtered Ga:ZnO transparent conducting thin films

    SciTech Connect

    Sigdel, Ajaya K.; Shaheen, Sean E.; Ndione, Paul F.; Perkins, John D.; Gennett, Thomas; Hest, Maikel F. A. M. van; Ginley, David S.; Berry, Joseph J.

    2012-05-01

    The utilization of radio-frequency (RF) superimposed direct-current (DC) magnetron sputtering deposition on the properties of gallium doped ZnO (GZO) based transparent conducting oxides has been examined. The GZO films were deposited using 76.2 mm diameter ZnO:Ga{sub 2}O{sub 3} (5 at. % Ga vs. Zn) ceramic oxide target on heated non-alkaline glass substrates by varying total power from 60 W to 120 W in steps of 20 W and at various power ratios of RF to DC changing from 0 to 1 in steps of 0.25. The GZO thin films grown with pure DC, mixed approach, and pure RF resulted in conductivities of 2200 {+-} 200 S/cm, 3920 {+-} 600 S/cm, and 3610 {+-} 400 S/cm, respectively. X-ray diffraction showed all films have wurtzite ZnO structure with the c-axis oriented perpendicular to the substrate. The films grown with increasing RF portion of the total power resulted in the improvement of crystallographic texture with smaller full-width half maximum in {chi} and broadening of optical gap with increased carrier concentration via more efficient doping. Independent of the total sputtering power, all films grown with 50% or higher RF power portion resulted in high mobility ({approx}28 {+-} 1 cm{sup 2}/Vs), consistent with observed improvements in crystallographic texture. All films showed optical transmittance of {approx}90% in the visible range.

  12. Evaluation of polymerization shrinkage of dental composites by an optical method.

    PubMed

    Weig, K M; Magalhães Filho, T R; Costa Neto, C A; Costa, M F

    2015-02-01

    This study proposes an alternative methodology for evaluating polymerization shrinkage of dental composites using an advanced video extensometer (AVE) system. This equipment measures the displacement between two points drawn on a tooth's wall without requiring physical contact with the tooth. By doing so, the polymerization process was monitored by the cusp deflection. This technique was used in human and bovine teeth, where the cavities were prepared under controlled conditions so that the volume of the composite used was the same in both types of teeth. After the cavity preparation, the specimens were acid etched, washed and dried, and then the adhesive was applied and polymerized. The composite was then inserted into the cavity. Polymerization was performed with two different light polymerizing units (LD Max and Optilight Max - Gnatus do Brasil), and the displacement curve of the tooth cusp was recorded for a period of 400 s. After a statistical analysis, it was concluded that the technique was capable of evaluating shrinkage by the deflection from the cusps and that the human and bovine teeth do not react in a similar manner towards the polymerization shrinkage of composites. PMID:25492174

  13. Acquiring concepts and features of novel words by two types of learning: direct mapping and inference.

    PubMed

    Chen, Shuang; Wang, Lin; Yang, Yufang

    2014-04-01

    This study examined the semantic representation of novel words learnt in two conditions: directly mapping a novel word to a concept (Direct mapping: DM) and inferring the concept from provided features (Inferred learning: IF). A condition where no definite concept could be inferred (No basic-level meaning: NM) served as a baseline. The semantic representation of the novel word was assessed via a semantic-relatedness judgment task. In this task, the learned novel word served as a prime, while the corresponding concept, an unlearned feature of the concept, and an unrelated word served as targets. ERP responses to the targets, primed by the novel words in the three learning conditions, were compared. For the corresponding concept, smaller N400s were elicited in the DM and IF conditions than in the NM condition, indicating that the concept could be obtained in both learning conditions. However, for the unlearned feature, the targets in the IF condition produced an N400 effect while in the DM condition elicited an LPC effect relative to the NM learning condition. No ERP difference was observed among the three learning conditions for the unrelated words. The results indicate that conditions of learning affect the semantic representation of novel word, and that the unlearned feature was only activated by the novel word in the IF learning condition.

  14. Dormant state of rifting below the Byrd Subglacial Basin, West Antarctica, implied by magnetotelluric (MT) profiling

    SciTech Connect

    Wannamaker, P.E.; Stodt, J.A.; Olsen, S.L.

    1996-10-01

    During the 1994{endash}1995 austral summer field season, we collected twelve, high-quality MT soundings over the Byrd Subglacial Basin of central West Antarctica (82{degree}36{prime}S lat., 118{degree}14{prime}W long. approx.) in the period range 0.01 s to 400 s. Ten equispaced sites in a 54 km profile cross regional aeromagnetic trends and complement seismic reflection and refraction results collected by others. Our purposes were to prove such measurements were feasible over the 2 km thick interior ice sheet, and to show from deep electrical resistivity whether the Byrd Basin comprises an active rift environment. The difficult acquisition of electric field data on ice was overcome using a custom electrometer system, with preamplifiers located at the electrode sites to buffer the high contact impedances of the ice as close to the source as possible. Two-dimensional modeling of the profile shows that resistivity of the deep crust and upper mantle is about 2000{endash}3000 ohm-m to 100 km depth or more. This is much higher than observed in active extensional regimes, suggesting that the current state of rifting, at least in this part of central West Antarctica, is dormant. {copyright} American Geophysical Union 1996

  15. Simultaneous determination of antioxidants, preservatives and sweetener additives in food and cosmetics by flow injection analysis coupled to a monolithic column.

    PubMed

    García-Jiménez, J F; Valencia, M C; Capitán-Vallvey, L F

    2007-07-01

    Today it is common to find samples with various additives from several families. This is the case of sweeteners, preservatives and antioxidants. We have selected a set of additives broadly used in foods and cosmetics with an ample variety of polarities, namely: aspartame (AS), acesulfame (AK)/saccharin (SA), methylparaben (MP), ethylparaben (EP), propylparaben (PP), butylparaben (BP), propylgallate (PG) and butylhydroxyanisole (BA). The monolithic column used as separative system is a 5 mm commercial precolumn of silica C18 coupled to a flow injection manifold working with a peristaltic pump. The mixture was separated in only 400 s with resolution factors greater than 1.1 in all cases. To achieve the separation in the FIA system we used two carriers: first, a mixture of ACN/water buffered with 10 mM pH 6.0 phosphate buffer and second, a methanol:water mixture to improve the carrier strength and speed up the more apolar analytes at 3.5 mL min(-1). Detection is accomplished by means of a diode array spectrometer at the respective wavelength of each compound. The comparison of the analytical parameters obtained for this procedure with a standard HPLC method validates our new method, obtaining a method that is quick, with high repeatability and reproducibility and with good resolution between analytes. We have successfully applied the method to real food and cosmetics samples.

  16. Single-molecule analysis of RAG-mediated V(D)J DNA cleavage

    PubMed Central

    Lovely, Geoffrey A.; Brewster, Robert C.; Schatz, David G.; Baltimore, David; Phillips, Rob

    2015-01-01

    The recombination-activating gene products, RAG1 and RAG2, initiate V(D)J recombination during lymphocyte development by cleaving DNA adjacent to conserved recombination signal sequences (RSSs). The reaction involves DNA binding, synapsis, and cleavage at two RSSs located on the same DNA molecule and results in the assembly of antigen receptor genes. We have developed single-molecule assays to examine RSS binding by RAG1/2 and their cofactor high-mobility group-box protein 1 (HMGB1) as they proceed through the steps of this reaction. These assays allowed us to observe in real time the individual molecular events of RAG-mediated cleavage. As a result, we are able to measure the binding statistics (dwell times) and binding energies of the initial RAG binding events and characterize synapse formation at the single-molecule level, yielding insights into the distribution of dwell times in the paired complex and the propensity for cleavage on forming the synapse. Interestingly, we find that the synaptic complex has a mean lifetime of roughly 400 s and that its formation is readily reversible, with only ∼40% of observed synapses resulting in cleavage at consensus RSS binding sites. PMID:25831509

  17. Odor-induced mood state modulates language comprehension by affecting processing strategies

    PubMed Central

    Wang, Lin; Zhou, Bin; Zhou, Wen; Yang, Yufang

    2016-01-01

    It is controversial whether mood affects cognition by triggering specific processing strategies or by limiting processing resources. The current event-related potential (ERP) study pursued this issue by examining how mood modulates the processing of task relevant/irrelevant information. In question-answer pairs, a question context marked a critical word in the answer sentence as focus (and thus relevant) or non-focus (thereby irrelevant). At the same time, participants were exposed to either a pleasant or unpleasant odor to elicit different mood states. Overall, we observed larger N400s when the critical words in the answer sentences were semantically incongruent (rather than congruent) with the question context. However, such N400 effect was only found for focused words accompanied by a pleasant odor and for both focused and non-focused words accompanied by an unpleasant odor, but not for non-focused words accompanied by a pleasant odor. These results indicate top-down attentional shift to the focused information in a positive mood state and non-selective attention allocated to the focused and non-focused information in a less positive mood state, lending support to the “processing strategy” hypothesis. By using a novel approach to induce mood states, our study provides fresh insights into the mechanisms underlying mood modulation of language comprehension. PMID:27796356

  18. Monthly Oceanic Rainfall from TRMM Microwave Imager (TMI) Data

    NASA Technical Reports Server (NTRS)

    Chang, Alfred T. C.; Chiu, Long S.

    2000-01-01

    We evaluated the performance of the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) at-launch algorithm for monthly oceanic rain rate using two years (January 1998 - December 1999) of TMI data. The TMI at-launch algorithm is based on Wilheit et al.'s technique for estimating monthly oceanic rainfall that relies on histograms of multichannel microwave measurements. Comparisons with oceanic monthly rain rates derived from the Defense Meteorological Satellite Program (DMSP) F-13 and F-14 Special Sensor Microwave Imager (SSM/I) data show the average rain rates over the TRMM region (between 400S and 40N) are 3.0, 2.85 and 2.89 mm/day, respectively for F-13, F-14 and TMI. Based on the latest version of TB data (version 5), both rainrate and freezing height derived from TMI are similar to those from the F-13 and F-14 SSM/I data. However, regionally the differences are statistically significant at the 95% confidence. Three hourly monthly rainrates are also computed from 3-hourly TB histograms to examine the diurnal cycle of precipitation. Over most of the oceanic TRMM area, a distinct early morning rainfall peak is found. A harmonic analysis shows that the amplitude of the 12h harmonic is significant and comparable to that of the 24h harmonic.

  19. Crystalline/amorphous tungsten oxide core/shell hierarchical structures and their synergistic effect for optical modulation.

    PubMed

    Zhou, D; Xie, D; Shi, F; Wang, D H; Ge, X; Xia, X H; Wang, X L; Gu, C D; Tu, J P

    2015-12-15

    High-performance electrochromic films with large color contrast and fast switching speed are of great importance for developing advanced smart windows. In this work, crystalline/amorphous WO3 core/shell (c-WO3@a-WO3) nanowire arrays rationally are synthesized by combining hydrothermal and electrodeposition methods. The 1D c-WO3@a-WO3 core/shell hierarchical structures show a synergistic effect for the enhancement of optical modulation, especially in the infrared (IR) region. By optimizing the electrodeposition time of 400s, the core/shell array exhibits a significant optical modulation (70.3% at 750nm, 42.0% at 2000nm and 51.4% at 10μm), fast switching speed (3.5s and 4.8s), high coloration efficiency (43.2cm(2)C(-1) at 750nm) and excellent cycling performance (68.5% after 3000 cycles). The crystalline/amorphous nanostructured film can provide an alternative way for developing high-performance electrochromic materials. PMID:26321573

  20. Ultra-light Hierarchical Graphene Electrode for Binder-Free Supercapacitors and Lithium-Ion Battery Anodes.

    PubMed

    Zuo, Zicheng; Kim, Tae Young; Kholmanov, Iskandar; Li, Huifeng; Chou, Harry; Li, Yuliang

    2015-10-01

    A mild and environmental-friendly method is developed for fabricating a 3D interconnected graphene electrode with large-scale continuity. Such material has interlayer pores between reduced graphene oxide nanosheets and in-plane pores. Hence, a specific surface area up to 835 m(2) g(-1) and a high powder conductivity up to 400 S m(-1) are achieved. For electrochemical applications, the interlayer pores can serve as "ion-buffering reservoirs" while in-plane ones act as "channels" for shortening the mass cross-plane diffusion length, reducing the ion response time, and prevent the interlayer restacking. As binder-free supercapacitor electrode, it delivers a specific capacitance up to 169 F g(-1) with surface-normalized capacitance close to 21 μF cm(-2) (intrinsic capacitance) and power density up to 7.5 kW kg(-1), in 6 m KOH aqueous electrolyte. In the case of lithium-ion battery anode, it shows remarkable advantages in terms of the initiate reversible Coulombic efficiency (61.3%), high specific capacity (932 mAh g(-1) at 100 mA g(-1)), and robust long-term retention (93.5% after 600 cycles at 2000 mAh g(-1)).

  1. Plasma modification of HEMA and EOEMA surface properties

    NASA Astrophysics Data System (ADS)

    Svorcik, V.; Kolarova, K.; Dvorankova, B.; Michalek, J.; Krumbholcova, E.; Hnatowicz, V.

    2006-01-01

    Process of plasma etching of poly(2-hydroxyethylmethacrylate) (HEMA) and poly(2-ethyloxyethyl methacrylate) (EOEMA) in Ar atmosphere at room temperature was studied. Ablation of the samples exposed to the plasma was determined by gravimetry, surface wettability by goniometry, chemical structure by FTIR spectroscopy and surface morphology by Scanning Electron (SEM) microscopy. Adhesion and proliferation of 3T3 mouse fibroblasts was studied in vitro in order to determine biological activity of plasma-modified HEMA and EOEMA substrates. It was demonstrated that the plasma etching leads to oxidation of HEMA and to an increase of its wettability. More estheric structures are produced in EOEMA. For both polymers, a surface layer similar to 2 mu m thick is ablated after plasma etching for 400 s. The etching changes the sample surface morphology and its biological activity. The surface becomes smoother after etching. The results obtained after 3T3 cells cultivation show that the plasma etching decreases cell adhesion and increases cell proliferation in comparison with pristine polymers.

  2. Removal of clomazone herbicide from a synthetic effluent by electrocoagulation.

    PubMed

    Benincá, Cristina; Vargas, Fernanda T; Martins, Manoel L; Gonçalves, Fábio F; Vargas, Rodrigo P; Freire, Flavio B; Zanoelo, Everton F

    2016-01-01

    The aim of this work was to investigate the kinetics of removal of clomazone herbicide from an aqueous solution by electrocoagulation. The experiments were performed in a cylindrical batch reactor with six aluminum electrodes in monopolar mode, arranged in series and connected to a digital DC power. The aqueous solution (tap water + clomazone) with initial pH close to 7.9 was always treated at ambient temperature (≈20 °C) and atmospheric pressure for 5,400 s. For a confidence level of 95% the rate constant of electrocoagulation and the efficiency of removal of clomazone at equilibrium were 2.1 × 10(-3) ± 0.5 × 10(-3) s(-1) and 97.7 ± 2.2%, respectively. The final chemical oxygen demand was 88% lower than that measured initially, while turbidity and apparent color were totally removed from the synthetic solution at a rate close to that of formation of aluminum hydroxides. Some reaction intermediates, such as benzonitrile-2-chloro and 2-chloro-hex-2,4-diene-1,6-dioic-acid determined by gas chromatography mass spectrometry (GC-MS) analysis, explain the ratio of equilibrium to initial total organic carbon approximately between 0.6 and 0.8 at a probability of 95%. PMID:27332840

  3. Shear Assisted Electrochemical Exfoliation of Graphite to Graphene.

    PubMed

    Shinde, Dhanraj B; Brenker, Jason; Easton, Christopher D; Tabor, Rico F; Neild, Adrian; Majumder, Mainak

    2016-04-12

    The exfoliation characteristics of graphite as a function of applied anodic potential (1-10 V) in combination with shear field (400-74 400 s(-1)) have been studied in a custom-designed microfluidic reactor. Systematic investigation by atomic force microscopy (AFM) indicates that at higher potentials thicker and more fragmented graphene sheets are obtained, while at potentials as low as 1 V, pronounced exfoliation is triggered by the influence of shear. The shear-assisted electrochemical exfoliation process yields large (∼10 μm) graphene flakes with a high proportion of single, bilayer, and trilayer graphene and small ID/IG ratio (0.21-0.32) with only a small contribution from carbon-oxygen species as demonstrated by X-ray photoelectron spectroscopy measurements. This method comprises intercalation of sulfate ions followed by exfoliation using shear induced by a flowing electrolyte. Our findings on the crucial role of hydrodynamics in accentuating the exfoliation efficiency suggest a safer, greener, and more automated method for production of high quality graphene from graphite.

  4. Strain rate effects on the mechanical behavior of two Dual Phase steels in tension

    NASA Astrophysics Data System (ADS)

    Cadoni, E.; Singh, N. K.; Forni, D.; Singha, M. K.; Gupta, N. K.

    2016-05-01

    This paper presents an experimental investigation on the strain rate sensitivity of Dual Phase steel 1200 (DP1200) and Dual Phase steel 1400 (DP1400) under uni-axial tensile loads in the strain rate range from 0.001 s-1 to 600 s-1. These materials are advanced high strength steels (AHSS) having high strength, high capacity to dissipate crash energy and high formability. Flat sheet specimens of the materials having gauge length 10 mm, width 4 mm and thickness 2 mm (DP1200) and 1.25 mm (DP1400), are tested at room temperature (20∘C) on electromechanical universal testing machine to obtain their stress-strain relation under quasi-static condition (0.001 s-1), and on Hydro-Pneumatic machine and modified Hopkinson bar to study their mechanical behavior at medium (3 s-1, and 18 s-1) and high strain rates (200 s-1, 400 s-1, and 600 s-1) respectively. Tests under quasi-static condition are performed at high temperature (200∘C) also, and found that tensile flow stress is a increasing function of temperature. The stress-strain data has been analysed to determine the material parameters of the Cowper-Symonds and the Johnson-Cook models. A simple modification of the Johnson-Cook model has been proposed in order to obtain a better fit of tests at high temperatures. Finally, the fractographs of the broken specimens are taken by scanning electron microscope (SEM) to understand the fracture mechanism of these advanced high strength steels at different strain rates.

  5. QUANTIFYING SPICULES

    SciTech Connect

    Pereira, Tiago M. D.; De Pontieu, Bart; Carlsson, Mats

    2012-11-01

    Understanding the dynamic solar chromosphere is fundamental in solar physics. Spicules are an important feature of the chromosphere, connecting the photosphere to the corona, potentially mediating the transfer of energy and mass. The aim of this work is to study the properties of spicules over different regions of the Sun. Our goal is to investigate if there is more than one type of spicule, and how spicules behave in the quiet Sun, coronal holes, and active regions. We make use of high cadence and high spatial resolution Ca II H observations taken by Hinode/Solar Optical Telescope. Making use of a semi-automated detection algorithm, we self-consistently track and measure the properties of 519 spicules over different regions. We find clear evidence of two types of spicules. Type I spicules show a rise and fall and have typical lifetimes of 150-400 s and maximum ascending velocities of 15-40 km s{sup -1}, while type II spicules have shorter lifetimes of 50-150 s, faster velocities of 30-110 km s{sup -1}, and are not seen to fall down, but rather fade at around their maximum length. Type II spicules are the most common, seen in the quiet Sun and coronal holes. Type I spicules are seen mostly in active regions. There are regional differences between quiet-Sun and coronal hole spicules, likely attributable to the different field configurations. The properties of type II spicules are consistent with published results of rapid blueshifted events (RBEs), supporting the hypothesis that RBEs are their disk counterparts. For type I spicules we find the relations between their properties to be consistent with a magnetoacoustic shock wave driver, and with dynamic fibrils as their disk counterpart. The driver of type II spicules remains unclear from limb observations.

  6. Processing of soft Hispanic cheese ("queso fresco") using thermo-sonicated milk: a study of physicochemical characteristics and storage life.

    PubMed

    Bermúdez-Aguirre, Daniela; Barbosa-Cánovas, Gustavo V

    2010-01-01

    Queso fresco is a handmade cheese consumed in Latin America and some regions of the United States. However, deficient milk processing has affected its microbial quality and it has an extremely short shelf life and low yield. The objective of this work was to process queso fresco using thermo-sonicated milk; physicochemical parameters were evaluated, including microbial quality during storage (4 °C). An ultrasonic processor (UP400S, 400 W, 24 kHz, 120 μm) was used to sonicate raw milk. Seven milk systems (500 mL each) were evaluated: 1 untreated, and 6 treated at 63 °C/30 min; 63 °C/10 min + sonication; 63 °C/30 min + sonication; 72 °C/15 s; 72 °C/15 s + sonication; and 72 °C/1 min + sonication. A conventional cheese-making process was followed for all systems. The effect of sonication on milk was quite noticeable. Curdling times were reduced considerably, cheese yield (20.6%) was almost doubled, and luminosity of cheese was increased (L*). Textural properties and microstructure images matched very well. Queso fresco processed at 63 °C/120 μm/30 min had the best quality. After storage for 23 d at 4 °C mesophilic count was just 4 log; psychrophilic count, 3.5 log; and enterobacteria count, 3 log. The pH and color remained almost constant and a minor degree of syneresis was observed at end of storage. Due to microstructural rearrangement of the milk components such as fat globules and casein micelles, cheese yield was doubled compared to the traditional handmade product. Shelf life was extended considerably and the product had higher quality.

  7. Aquatic biofouling prevention by electrically charged nanocomposite polymer thin film membranes.

    PubMed

    de Lannoy, Charles-François; Jassby, David; Gloe, Katie; Gordon, Alexander D; Wiesner, Mark R

    2013-03-19

    Electrically conductive polymer-nanocomposite (ECPNC) tight nanofiltration (NF) thin film membranes were demonstrated to have biofilm-preventing capabilities under extreme bacteria and organic material loadings. A simple route to the creation and application of these polyamide-carbon nanotube thin films is also reported. These thin films were characterized with SEM and TEM as well as FTIR to demonstrate that the carbon nanotubes are embedded within the polyamide and form ester bonds with trimesoyl chloride, one of the monomers of polyamide. These polymer nanocomposite thin film materials boast high electrical conductivity (∼400 S/m), good NaCl rejection (>95%), and high water permeability. To demonstrate these membranes' biofouling capabilities, we designed a cross-flow water filtration vessel with insulated electrical leads connecting the ECPNC membranes to an arbitrary waveform generator. In all experiments, conducted in highly bacterially contaminated LB media, flux tests were run until fluxes decreased by 45 ± 3% over initial flux. Biofilm-induced, nonreversible flux decline was observed in all control experiments and a cross-flow rinse with the feed solution failed to induce flux recovery. In contrast, flux decrease for the ECPNC membranes with an electric potential applied to their surface was only caused by deposition of bacteria rather than bacterial attachment, and flux was fully recoverable following a short rinse with the feed solution and no added cleaning agents. The prevention of biofilm formation on the ECPNC membranes was a long-term effect, did not decrease with use, and was highly reproducible. PMID:23413920

  8. Quantification, Prediction, and the Online Impact of Sentence Truth-Value: Evidence From Event-Related Potentials

    PubMed Central

    2015-01-01

    Do negative quantifiers like “few” reduce people’s ability to rapidly evaluate incoming language with respect to world knowledge? Previous research has addressed this question by examining whether online measures of quantifier comprehension match the “final” interpretation reflected in verification judgments. However, these studies confounded quantifier valence with its impact on the unfolding expectations for upcoming words, yielding mixed results. In the current event-related potentials study, participants read negative and positive quantifier sentences matched on cloze probability and on truth-value (e.g., “Most/Few gardeners plant their flowers during the spring/winter for best results”). Regardless of whether participants explicitly verified the sentences or not, true-positive quantifier sentences elicited reduced N400s compared with false-positive quantifier sentences, reflecting the facilitated semantic retrieval of words that render a sentence true. No such facilitation was seen in negative quantifier sentences. However, mixed-effects model analyses (with cloze value and truth-value as continuous predictors) revealed that decreasing cloze values were associated with an interaction pattern between truth-value and quantifier, whereas increasing cloze values were associated with more similar truth-value effects regardless of quantifier. Quantifier sentences are thus understood neither always in 2 sequential stages, nor always in a partial-incremental fashion, nor always in a maximally incremental fashion. Instead, and in accordance with prediction-based views of sentence comprehension, quantifier sentence comprehension depends on incorporation of quantifier meaning into an online, knowledge-based prediction for upcoming words. Fully incremental quantifier interpretation occurs when quantifiers are incorporated into sufficiently strong online predictions for upcoming words. PMID:26375784

  9. Fast “Feast/Famine” Cycles for Studying Microbial Physiology Under Dynamic Conditions: A Case Study with Saccharomyces cerevisiae

    PubMed Central

    Suarez-Mendez, Camilo A.; Sousa, Andre; Heijnen, Joseph J.; Wahl, Aljoscha

    2014-01-01

    Microorganisms are constantly exposed to rapidly changing conditions, under natural as well as industrial production scale environments, especially due to large-scale substrate mixing limitations. In this work, we present an experimental approach based on a dynamic feast/famine regime (400 s) that leads to repetitive cycles with moderate changes in substrate availability in an aerobic glucose cultivation of Saccharomyces cerevisiae. After a few cycles, the feast/famine produced a stable and repetitive pattern with a reproducible metabolic response in time, thus providing a robust platform for studying the microorganism’s physiology under dynamic conditions. We found that the biomass yield was slightly reduced (−5%) under the feast/famine regime, while the averaged substrate and oxygen consumption as well as the carbon dioxide production rates were comparable. The dynamic response of the intracellular metabolites showed specific differences in comparison to other dynamic experiments (especially stimulus-response experiments, SRE). Remarkably, the frequently reported ATP paradox observed in single pulse experiments was not present during the repetitive perturbations applied here. We found that intracellular dynamic accumulations led to an uncoupling of the substrate uptake rate (up to 9-fold change at 20 s.) Moreover, the dynamic profiles of the intracellular metabolites obtained with the feast/famine suggest the presence of regulatory mechanisms that resulted in a delayed response. With the feast famine setup many cellular states can be measured at high frequency given the feature of reproducible cycles. The feast/famine regime is thus a versatile platform for systems biology approaches, which can help us to identify and investigate metabolite regulations under realistic conditions (e.g., large-scale bioreactors or natural environments). PMID:24957030

  10. Longitudinal compressive behaviour of 3D braided composite under various temperatures and strain rates

    NASA Astrophysics Data System (ADS)

    Pan, Zhongxiang; Gu, Bohong; Sun, Baozhong

    2015-03-01

    This paper reports the longitudinal compressive behaviour of 3D braided basalt fibre tows/epoxy composite materials under strain-rate range of 1,200-2,400 s-1 and temperature range of 23-210 °C both in experimental and finite element analyses (FEA). A split Hopkinson pressure bar system with a heating device was designed to test the longitudinal compressive behaviour of 3D braided composite materials. Testing results indicate that longitudinal compression modulus, specific energy absorption and peak stress decreased with elevated temperatures, whereas the failure strain increased with elevated temperatures. At some temperatures above the T g of epoxy resin, such as at 120 and 150 °C, strain distributions and deformations in fibre tows and epoxy resin tended to be the same. It results in relatively slighter damage status of the 3D braided composite material. The FEA results reveal that heating of the material due to the dissipative energy of the inelastic deformation and damage processes generated in resin is more than that in fibre tows. The braiding structure has a significant influence on thermomechanical failure via two aspects: distribution and accumulation of the heating leads to the development of the shear band paths along braiding angle; the buckling inflection segment rather than the straight segment generates the maximum of the heating in each fibre tows. The damage occurs at the early stage when the temperature is below T g, while at the temperature above T g, damage stage occurs at the rear of plastic deformation.

  11. MAGNETIC AND DYNAMICAL PHOTOSPHERIC DISTURBANCES OBSERVED DURING AN M3.2 SOLAR FLARE

    SciTech Connect

    Kuckein, C.; Collados, M.; Sainz, R. Manso

    2015-02-01

    This Letter reports on a set of full-Stokes spectropolarimetric observations in the near-infrared He i 10830 Å spectral region covering the pre-flare, flare, and post-flare phases of an M3.2 class solar flare. The flare originated on 2013 May 17 and belonged to active region NOAA 11748. We detected strong He i 10830 Å emission in the flare. The red component of the He i triplet peaks at an intensity ratio to the continuum of about 1.86. During the flare, He i Stokes V is substantially larger and appears reversed compared to the usually larger Si i Stokes V profile. The photospheric Si i inversions of the four Stokes profiles reveal the following: (1) the magnetic field strength in the photosphere decreases or is even absent during the flare phase, as compared to the pre-flare phase. However, this decrease is not permanent. After the flare, the magnetic field recovers its pre-flare configuration in a short time (i.e., 30 minutes after the flare). (2) In the photosphere, the line of sight velocities show a regular granular up- and downflow pattern before the flare erupts. During the flare, upflows (blueshifts) dominate the area where the flare is produced. Evaporation rates of ∼10{sup −3} and ∼10{sup −4} g cm{sup −2} s{sup −1} have been derived in the deep and high photosphere, respectively, capable of increasing the chromospheric density by a factor of two in about 400 s.

  12. Assessment of total efficiency in adiabatic engines

    NASA Astrophysics Data System (ADS)

    Mitianiec, W.

    2016-09-01

    The paper presents influence of ceramic coating in all surfaces of the combustion chamber of SI four-stroke engine on working parameters mainly on heat balance and total efficiency. Three cases of engine were considered: standard without ceramic coating, fully adiabatic combustion chamber and engine with different thickness of ceramic coating. Consideration of adiabatic or semi-adiabatic engine was connected with mathematical modelling of heat transfer from the cylinder gas to the cooling medium. This model takes into account changeable convection coefficient based on the experimental formulas of Woschni, heat conductivity of multi-layer walls and also small effect of radiation in SI engines. The simulation model was elaborated with full heat transfer to the cooling medium and unsteady gas flow in the engine intake and exhaust systems. The computer program taking into account 0D model of engine processes in the cylinder and 1D model of gas flow was elaborated for determination of many basic engine thermodynamic parameters for Suzuki DR-Z400S 400 cc SI engine. The paper presents calculation results of influence of the ceramic coating thickness on indicated pressure, specific fuel consumption, cooling and exhaust heat losses. Next it were presented comparisons of effective power, heat losses in the cooling and exhaust systems, total efficiency in function of engine rotational speed and also comparison of temperature inside the cylinder for standard, semi-adiabatic and full adiabatic engine. On the basis of the achieved results it was found higher total efficiency of adiabatic engines at 2500 rpm from 27% for standard engine to 37% for full adiabatic engine.

  13. The Truth Before and After: Brain Potentials Reveal Automatic Activation of Event Knowledge during Sentence Comprehension.

    PubMed

    Nieuwland, Mante S

    2015-11-01

    How does knowledge of real-world events shape our understanding of incoming language? Do temporal terms like "before" and "after" impact the online recruitment of real-world event knowledge? These questions were addressed in two ERP experiments, wherein participants read sentences that started with "before" or "after" and contained a critical word that rendered each sentence true or false (e.g., "Before/After the global economic crisis, securing a mortgage was easy/harder"). The critical words were matched on predictability, rated truth value, and semantic relatedness to the words in the sentence. Regardless of whether participants explicitly verified the sentences or not, false-after-sentences elicited larger N400s than true-after-sentences, consistent with the well-established finding that semantic retrieval of concepts is facilitated when they are consistent with real-world knowledge. However, although the truth judgments did not differ between before- and after-sentences, no such sentence N400 truth value effect occurred in before-sentences, whereas false-before-sentences elicited an enhanced subsequent positive ERPs. The temporal term "before" itself elicited more negative ERPs at central electrode channels than "after." These patterns of results show that, irrespective of ultimate sentence truth value judgments, semantic retrieval of concepts is momentarily facilitated when they are consistent with the known event outcome compared to when they are not. However, this inappropriate facilitation incurs later processing costs as reflected in the subsequent positive ERP deflections. The results suggest that automatic activation of event knowledge can impede the incremental semantic processes required to establish sentence truth value. PMID:26244719

  14. Development of ITER 15 MA ELMy H-mode Inductive Scenario

    SciTech Connect

    Kessel, C. E.; Campbell, D.; Gribov, Y.; Saibene, G.; Ambrosino, G.; Casper, T.; Cavinato, M.; Fujieda, H.; Hawryluk, R.; Horton, L. D.; Kavin, A.; Kharyrutdinov, R.; Koechl, F.; Leuer, J.; Loarte, A.; Lomas, P. J.; Luce, T.; Lukash, V.; Mattei, M.; Nunes, I.; Parail, V.; Polevoi, A.; Portone, A.; Sartori, R.; Sips, A. C.C.; Thomas, P. R.; Welander, A.; Wesley, J.

    2008-10-16

    The poloidal field (PF) coil system on ITER, which provides both feedforward and feedback control of plasma position, shape, and current, is a critical element for achieving mission performance. Analysis of PF capabilities has focused on the 15 MA Q = 10 scenario with a 300-500 s flattop burn phase. The operating space available for the 15 MA ELMy H-mode plasma discharges in ITER and upgrades to the PF coils or associated systems to establish confidence that ITER mission objectives can be reached have been identified. Time dependent self-consistent free-boundary calculations were performed to examine the impact of plasma variability, discharge programming, and plasma disturbances. Based on these calculations a new reference scenario was developed based upon a large bore initial plasma, early divertor transition, low level heating in L-mode, and a late H-mode onset. Equilibrium analyses for this scenario indicate that the original PF coil limitations do not allow low li (<0.8) operation or lower flux states, and the flattop burn durations were predicted to be less than the desired 400 s. This finding motivates the expansion of the operating space, considering several upgrade options to the PF coils. Analysis was also carried out to examine the feedback current reserve required in the CS and PF coils during a series of disturbances and a feasibility assessment of the 17 MA scenario was undertaken. Results of the studies show that the new scenario and modified PF system will allow a wide range of 15 MA 300-500 s operation and more limited but finite 17 MA operation.

  15. 2,3-Dihydro-2,5-dihydroxy-4H-benzopyran-4-one: a nonphysiological substrate for fungal melanin biosynthetic enzymes.

    PubMed

    Thompson, J E; Basarab, G S; Pierce, J; Hodge, C N; Jordan, D B

    1998-02-01

    We have synthesized an alternate substrate for trihydroxynaphthalene reductase (3HNR) and scytalone dehydratase (SD), two enzymes in the fungal melanin biosynthetic pathway. The oxidation of 2,3-dihydro-2,5-dihydroxy-4H-benzopyran-4-one (DDBO) to 4,5-dihydroxy-2H-benzopyran-2-one (DBO) with concomitant reduction of NADP+ is catalyzed by 3HNR. DDBO is dehydrated by SD to 5-hydroxy-4H-1-benzopyran-4-one (HBO). These reactions can be monitored using continuous spectrophotometric assays. DDBO race-mizes rapidly, so chiral synthesis to mimic the natural substrate is not required. DDBO, DBO, and HBO are stable in aerated aqueous solution, in contrast to the rapidly autooxidizing trihydroxynaphthalene, a physiological substrate for 3HNR and product of SD. Unlike the natural substrates, DDBO, DBO, and HBO do not change protonation state between pH's 4 and 9. Oxidation of DDBO is effectively irreversible at pH 7, as DBO deprotonates with a pKa of 2.5. At pH 7.0 and 25 degrees C, the kcat for 3HNR catalyzed DDBO oxidation is 14 s-1 and the K(m) is 5 microM; the kcat for SD catalyzed DDBO dehydration is 400 s-1 and the K(m) is 15 microM. Based on these kinetic constants, DDBO is a better substrate than the natural substrate scytalone for both 3HNR and SD at neutral pH. An explanation for the preference of DDBO over scytalone in the oxidation and dehydration reactions is offered.

  16. The reliability of the N400 in single subjects: Implications for patients with disorders of consciousness

    PubMed Central

    Cruse, Damian; Beukema, Steve; Chennu, Srivas; Malins, Jeffrey G.; Owen, Adrian M.; McRae, Ken

    2014-01-01

    Functional neuroimaging assessments of residual cognitive capacities, including those that support language, can improve diagnostic and prognostic accuracy in patients with disorders of consciousness. Due to the portability and relative inexpensiveness of electroencephalography, the N400 event-related potential component has been proposed as a clinically valid means to identify preserved linguistic function in non-communicative patients. Across three experiments, we show that changes in both stimuli and task demands significantly influence the probability of detecting statistically significant N400 effects — that is, the difference in N400 amplitudes caused by the experimental manipulation. In terms of task demands, passively heard linguistic stimuli were significantly less likely to elicit N400 effects than task-relevant stimuli. Due to the inability of the majority of patients with disorders of consciousness to follow task commands, the insensitivity of passive listening would impede the identification of residual language abilities even when such abilities exist. In terms of stimuli, passively heard normatively associated word pairs produced the highest detection rate of N400 effects (50% of the participants), compared with semantically-similar word pairs (0%) and high-cloze sentences (17%). This result is consistent with a prediction error account of N400 magnitude, with highly predictable targets leading to smaller N400 waves, and therefore larger N400 effects. Overall, our data indicate that non-repeating normatively associated word pairs provide the highest probability of detecting single-subject N400s during passive listening, and may thereby provide a clinically viable means of assessing residual linguistic function. We also show that more liberal analyses may further increase the detection-rate, but at the potential cost of increased false alarms. PMID:24936429

  17. Particle Detectors and Data Analysis for Cusp Transient Features Campaign

    NASA Technical Reports Server (NTRS)

    Sharber, James R.

    1998-01-01

    On December 3, 1997, a rocket payload (36.152) was launched from Ny Alesund into the dark cusp at 0906:00 U (1206:00 LT) during an interval of southward B(sub Z), and positive B(sub y). Launch occurred during a time interval of northeastward moving auroral forms observed between 0845 and 0945 UT by ground-based meridian scanning photometers. Ground photometric measurements during the flight show that the payload passed over the poleward portion of the most intense 6300 A emissions of the dayside cusp/cleft region. Electrons of energy up to a few hundred eV were detected immediately upon instrument turn-on at an altitude of 205 km and throughout the flight until the payload reached an altitude of approximately 197 km on the downleg. Electron spectra were either quasithermal with peak energies approximately 100 eV or showed evidence of acceleration along the magnetic field line by potentials of 100-200 V. Precipitating ions were observed throughout much of the flight. Their spectra were broadly peaked in energy with the peak energy decreasing from approximately 500 eV to approximately 250 eV as the payload flew approximately westward over the dayside precipitationregion. Structure(spatial or temporal intensity variation) was observed between T + 180 s and T + approximately 400 s. At the rocket altitudes(less than 450km) the ions were observed to be precipitating. During the flight, the DMSPF-13 satellite passed through the all-sky imager field-of-view just poleward of the brightest dayside emissions enabling the identification of plasma sheet and boundary layer regions along the orbit. We thus conclude that particle fluxes detected by the rocket flight were either cusp plasma or boundary layer/mantle plasmajust poleward of the dayside cusp/cleft. Further investigation of the particle characteristics and their relationship to ionospheric convection patterns is continuing.

  18. Particle Detectors and Data Analysis for Cusp Transient Features Campaign

    NASA Technical Reports Server (NTRS)

    Sharber, James R.

    1999-01-01

    On December 3, 1997, a rocket payload (36.152) was launched from N(sub y) Alesund into the dark cusp at 0906:00 U (1206:00 LT) during an interval of southward B(sub z) and positive B(sub y). Launch occurred during a time interval of northeastward moving auroral forms observed between 0845 and 0945 UT by ground-based meridian scanning photometers. Ground photometric measurements during the flight show that the payload passed over the poleward portion of the most intense 6300 A emissions of the dayside cusp/cleft region. Electrons of energy up to a few hundred eV were detected immediately upon instrument turn-on at an altitude of 205 km and throughout the flight until the payload reached an altitude of -197 km on the downleg. Electron spectra were either quasithermal with peak energies -100 eV or showed evidence of acceleration along the magnetic field line by potentials of 100-200 V. Precipitating ions were observed throughout much of the flight. Their spectra were broadly peaked in energy with the peak energy decreasing from -500 eV to -250 eV as the payload flew approximately westward over the dayside precipitation region. Structure (spatial or temporal intensity variation) was observed between T + 180 s and T + -400 s. At the rocket altitudes (<450 km) the ions were observed to be precipitating. During the flight, the DMSP F-13 satellite passed through the all-sky imager field-of-view just poleward of the brightest dayside emissions enabling the identification of plasma sheet and boundary layer regions along the orbit. We thus conclude that particle fluxes detected by the rocket flight were either cusp plasma or boundary layer/mantle plasma just poleward of the dayside cusp/cleft. A paper describing the fields and plasmas observed during the flight is now being prepared for publication.

  19. Quantification, prediction, and the online impact of sentence truth-value: Evidence from event-related potentials.

    PubMed

    Nieuwland, Mante S

    2016-02-01

    Do negative quantifiers like "few" reduce people's ability to rapidly evaluate incoming language with respect to world knowledge? Previous research has addressed this question by examining whether online measures of quantifier comprehension match the "final" interpretation reflected in verification judgments. However, these studies confounded quantifier valence with its impact on the unfolding expectations for upcoming words, yielding mixed results. In the current event-related potentials study, participants read negative and positive quantifier sentences matched on cloze probability and on truth-value (e.g., "Most/Few gardeners plant their flowers during the spring/winter for best results"). Regardless of whether participants explicitly verified the sentences or not, true-positive quantifier sentences elicited reduced N400s compared with false-positive quantifier sentences, reflecting the facilitated semantic retrieval of words that render a sentence true. No such facilitation was seen in negative quantifier sentences. However, mixed-effects model analyses (with cloze value and truth-value as continuous predictors) revealed that decreasing cloze values were associated with an interaction pattern between truth-value and quantifier, whereas increasing cloze values were associated with more similar truth-value effects regardless of quantifier. Quantifier sentences are thus understood neither always in 2 sequential stages, nor always in a partial-incremental fashion, nor always in a maximally incremental fashion. Instead, and in accordance with prediction-based views of sentence comprehension, quantifier sentence comprehension depends on incorporation of quantifier meaning into an online, knowledge-based prediction for upcoming words. Fully incremental quantifier interpretation occurs when quantifiers are incorporated into sufficiently strong online predictions for upcoming words.

  20. Teleseismically-induced tremor near Parkfield, CA - a cacophony or a symphony?

    NASA Astrophysics Data System (ADS)

    Vidale, J. E.; Peng, Z.; Creager, K. C.; Bodin, P.

    2007-12-01

    The tremor triggered near Parkfield, CA by the 2002 Denali and 2004 Sumatra earthquakes was strong and well recorded by the dense regional CISN and the borehole HRSN networks. Peng et al. (this meeting) survey tremors triggered by a larger set of 12 regional and teleseismic events, providing a broader context. In the case of both the 2002 M7.9 Denali and 2004 M9.1 Sumatra earthquakes, the tremor emanates from at least two source regions deep within the SAF. The first source region is 40 km NW of the SAFOD in the creeping section of the SAF, and the second region is 40 km SE of the SAFOD near Cholame, close to the location where most of the non-triggered tremor has been found previously (Nadeau and Dolenc, Science, 2005). The Denali earthquake triggered tremor is in phase with the surface waves for about 400s. The northern region started tremoring first by about 100s, and both regions quieted before the end of the surface waves. The wavetrain for the 2004 M9.1 Sumatra earthquake was long enough that tremors were also excited by the weak diffracted P waves, and tremor turned up the volume for an hour upon the arrival of the surface waves, underwent a sudden and curious hiatus for 500s before the end of the surface waves, then re-started and continued for at least an hour after the passage of the surface waves. It is easy to suggest that the tremor was accompanied by deep slip on the SAF, but creep and strain data indicate any slip was too small to generate a detectable surface deformation. These observations suggest a component of driven, instantaneous, perhaps Coulomb-friction response with an added dose of self-sustaining, dribbling activity more suggestive of the oozing of fluids.

  1. Elasticity Imaging of Polymeric Media

    PubMed Central

    Sridhar, Mallika; Liu, Jie; Insana, Michael F.

    2009-01-01

    Viscoelastic properties of soft tissues and hydropolymers depend on the strength of molecular bonding forces connecting the polymer matrix and surrounding fluids. The basis for diagnostic imaging is that disease processes alter molecular-scale bonding in ways that vary the measurable stiffness and viscosity of the tissues. This paper reviews linear viscoelastic theory as applied to gelatin hydrogels for the purpose of formulating approaches to molecular-scale interpretation of elasticity imaging in soft biological tissues. Comparing measurements acquired under different geometries, we investigate the limitations of viscoelastic parameters acquired under various imaging conditions. Quasistatic (step-and-hold and low-frequency harmonic) stimuli applied to gels during creep and stress relaxation experiments in confined and unconfined geometries reveal continuous, bimodal distributions of respondance times. Within the linear range of responses, gelatin will behave more like a solid or fluid depending on the stimulus magnitude. Gelatin can be described statistically from a few parameters of low-order rheological models that form the basis of viscoelastic imaging. Unbiased estimates of imaging parameters are obtained only if creep data are acquired for greater than twice the highest retardance time constant and any steady-state viscous response has been eliminated. Elastic strain and retardance time images are found to provide the best combination of contrast and signal strength in gelatin. Retardance times indicate average behavior of fast (1–10 s) fluid flows and slow (50–400 s) matrix restructuring in response to the mechanical stimulus. Insofar as gelatin mimics other polymers, such as soft biological tissues, elasticity imaging can provide unique insights into complex structural and biochemical features of connectives tissues affected by disease. PMID:17408331

  2. Real-time monitoring and verification of in vivo high dose rate brachytherapy using a pinhole camera.

    PubMed

    Duan, J; Macey, D J; Pareek, P N; Brezovich, I A

    2001-02-01

    We investigated a pinhole imaging system for independent in vivo monitoring and verification of high dose rate (HDR) brachytherapy treatment. The system consists of a high-resolution pinhole collimator, an x-ray fluoroscope, and a standard radiographic screen-film combination. Autofluoroscopy provides real-time images of the in vivo Ir-192 HDR source for monitoring the source location and movement, whereas autoradiography generates a permanent record of source positions on film. Dual-pinhole autoradiographs render stereo-shifted source images that can be used to reconstruct the source dwell positions in three dimensions. The dynamic range and spatial resolution of the system were studied with a polystyrene phantom using a range of source strengths and dwell times. For the range of source activity used in HDR brachytherapy, a 0.5 mm diameter pinhole produced sharp fluoroscopic images of the source within the dynamic range of the fluoroscope. With a source-to-film distance of 35 cm and a 400 speed screen-film combination, the same pinhole yielded well recognizable images of a 281.2 GBq (7.60 Ci) Ir-192 source for dwell times in the typical clinical range of 2 to 400 s. This 0.5 mm diameter pinhole could clearly resolve source positions separated by lateral displacements as small as 1 mm. Using a simple reconstruction algorithm, dwell positions in a phantom were derived from stereo-shifted dual-pinhole images and compared to the known positions. The agreement was better than 1 mm. A preliminary study of a patient undergoing HDR treatment for cervical cancer suggests that the imaging method is clinically feasible. Based on these studies we believe that the pinhole imaging method is capable of providing independent and reliable real-time monitoring and verification for HDR brachytherapy.

  3. Continuum emission-based electron diagnostics for atmospheric pressure plasmas and characteristics of nanosecond-pulsed argon plasma jets

    NASA Astrophysics Data System (ADS)

    Park, Sanghoo; Choe, Wonho; Kim, Holak; Park, Joo Young

    2015-06-01

    Electron diagnostics based on electron-neutral atom (e-a) bremsstrahlung in the UV and visible range emitted from atmospheric pressure plasmas is presented. Since the spectral emissivity of the e-a bremsstrahlung is determined by electron density (ne) and mean electron temperature (Te) representing the Maxwellian electron energy distribution, their diagnostics is possible. As an example, emission spectra measured from capacitive discharges are presented, which show good agreement with the theoretically calculated emissivity of the e-a bremsstrahlung. For a single pin electrode nanosecond-pulsed plasma jet (n-PPJ) in argon, we investigate the electron properties and the temporal behavior of the positive streamers. Streamers with many branches are clearly observed inside the dielectric tube, while a few main streamers propagate outside the tube along the jet axis. A two-dimensional (2D) measurement of the time-averaged Te distribution was developed using a commercial digital camera and optical band pass filters based on the emissivity ratio of two wavelengths of the e-a bremsstrahlung. The viable measurement range of Te is 0.5-7 eV for the choice of two wavelengths of 300s and 900s nm and 0.5-4 eV for two wavelengths of 400s and 900s nm, which are uncontaminated by the atomic and/or molecular spectra. The 2D Te distribution obtained using 514.5 and 632.8 nm emissions helps to reveal the role of electrons in streamer characteristics in the argon n-PPJ. Time-averaged Te of 2.0 eV and 1.0 eV inside and outside the tube, respectively, were measured. The streamer dynamics of the n-PPJ is shown to be dependent on Te.

  4. Automatic Semantic Priming Abnormalities in Schizophrenia

    PubMed Central

    Mathalon, Daniel H.; Roach, Brian J.; Ford, Judith M.

    2014-01-01

    Abnormal activation of semantic networks characterizes schizophrenia and can be studied using the N400 event-related potential (ERP). N400 is elicited by words that are not primed by the preceding context and provides a direct measure of the neural mechanisms underlying semantic priming. Semantic priming refers to facilitated semantic processing gained through pre-exposure to semantic context, which can happen automatically if the interval between the prime and target is very short. We predicted that (1) schizophrenia patients have overly inclusive semantic networks, reflected in a less negative than expected N400 to relatively unprimed words, and (2) schizophrenia patients are deficient in their use of semantic context, responding to primed words as if they were unprimed, reflected in a more negative than expected N400 to primed words. N400s were acquired from patients with DSM-IV schizophrenia (n=26) and age-matched healthy comparison subjects (n=29) performing a picture-word verification (match vs. non-match) task. Word targets were presented 325ms after a picture prime, which either matched (CAMEL→”camel”), or did not match (In Category: CAMEL→”cow; Out Category: CAMEL→”candle”) the prime. N400 data suggest that both patients and controls are sensitive to the difference between primed and unprimed words, but patients are less sensitive than controls. Similarly, N400 data suggest that both groups were sensitive to the subtler difference between classes of unprimed words (In Category versus Out Category picture-word non-matches), but patients are less sensitive, especially those with prominent negative symptoms. PMID:19995582

  5. Genetic and genomic insights into the role of benzoate-catabolic pathway redundancy in Burkholderia xenovorans LB400.

    PubMed

    Denef, V J; Klappenbach, J A; Patrauchan, M A; Florizone, C; Rodrigues, J L M; Tsoi, T V; Verstraete, W; Eltis, L D; Tiedje, J M

    2006-01-01

    Transcriptomic and proteomic analyses of Burkholderia xenovorans LB400, a potent polychlorinated biphenyl (PCB) degrader, have implicated growth substrate- and phase-dependent expression of three benzoate-catabolizing pathways: a catechol ortho cleavage (ben-cat) pathway and two benzoyl-coenzyme A pathways, encoded by gene clusters on the large chromosome (boxC) and the megaplasmid (boxM). To elucidate the significance of this apparent redundancy, we constructed mutants with deletions of the ben-cat pathway (the DeltabenABCD::kan mutant), the boxC pathway (the DeltaboxABC::kan mutant), and both pathways (the DeltabenABCDDelta boxABC::kan mutant). All three mutants oxidized benzoate in resting-cell assays. However, the DeltabenABCD::kan and DeltabenABCD DeltaboxABC::kan mutants grew at reduced rates on benzoate and displayed increased lag phases. By contrast, growth on succinate, on 4-hydroxybenzoate, and on biphenyl was unaffected. Microarray and proteomic analyses revealed that cells of the DeltabenABCD::kan mutant growing on benzoate expressed both box pathways. Overall, these results indicate that all three pathways catabolize benzoate. Deletion of benABCD abolished the ability of LB400 to grow using 3-chlorobenzoate. None of the benzoate pathways could degrade 2- or 4-chlorobenzoate, indicating that the pathway redundancy does not directly contribute to LB400's PCB-degrading capacities. Finally, an extensive sigmaE-regulated oxidative stress response not present in wild-type LB400 grown on benzoate was detected in these deletion mutants, supporting our earlier suggestion that the box pathways are preferentially active under reduced oxygen tension. Our data further substantiate the expansive network of tightly interconnected and complexly regulated aromatic degradation pathways in LB400. PMID:16391095

  6. OBSERVATIONAL STUDY OF THE QUASI-PERIODIC FAST-PROPAGATING MAGNETOSONIC WAVES AND THE ASSOCIATED FLARE ON 2011 MAY 30

    SciTech Connect

    Shen Yuandeng; Liu Yu

    2012-07-01

    On 2011 May 30, quasi-periodic fast-propagating (QFP) magnetosonic waves accompanied by a C2.8 flare were directly imaged by the Atmospheric Imaging Assembly instrument on board the Solar Dynamics Observatory. The QFP waves successively emanated from the flare kernel, they propagated along a cluster of open coronal loops with a phase speed of {approx}834 km s{sup -1} during the flare's rising phase, and the multiple arc-shaped wave trains can be fitted with a series of concentric circles. We generate the k - {omega} diagram of the Fourier power and find a straight ridge that represents the dispersion relation of the waves. Along the ridge, we find a lot of prominent nodes which represent the available frequencies of the QFP waves. On the other hand, the frequencies of the flare are also obtained by analyzing the flare light curves using the wavelet technique. The results indicate that almost all the main frequencies of the flare are consistent with those of the QFP waves. This suggests that the flare and the QFP waves were possibly excited by a common physical origin. On the other hand, a few low frequencies (e.g., 2.5 mHz (400 s) and 0.7 mHz (1428 s)) revealed by the k - {omega} diagram cannot be found in the accompanying flare. We propose that these low frequencies were possibly due to the leakage of the pressure-driven p-mode oscillations from the photosphere into the low corona, which should be a noticeable mechanism for driving the QFP waves observed in the corona.

  7. The Truth Before and After: Brain Potentials Reveal Automatic Activation of Event Knowledge during Sentence Comprehension.

    PubMed

    Nieuwland, Mante S

    2015-11-01

    How does knowledge of real-world events shape our understanding of incoming language? Do temporal terms like "before" and "after" impact the online recruitment of real-world event knowledge? These questions were addressed in two ERP experiments, wherein participants read sentences that started with "before" or "after" and contained a critical word that rendered each sentence true or false (e.g., "Before/After the global economic crisis, securing a mortgage was easy/harder"). The critical words were matched on predictability, rated truth value, and semantic relatedness to the words in the sentence. Regardless of whether participants explicitly verified the sentences or not, false-after-sentences elicited larger N400s than true-after-sentences, consistent with the well-established finding that semantic retrieval of concepts is facilitated when they are consistent with real-world knowledge. However, although the truth judgments did not differ between before- and after-sentences, no such sentence N400 truth value effect occurred in before-sentences, whereas false-before-sentences elicited an enhanced subsequent positive ERPs. The temporal term "before" itself elicited more negative ERPs at central electrode channels than "after." These patterns of results show that, irrespective of ultimate sentence truth value judgments, semantic retrieval of concepts is momentarily facilitated when they are consistent with the known event outcome compared to when they are not. However, this inappropriate facilitation incurs later processing costs as reflected in the subsequent positive ERP deflections. The results suggest that automatic activation of event knowledge can impede the incremental semantic processes required to establish sentence truth value.

  8. Fabrication and In vivo Thrombogenicity Testing of Nitric Oxide Generating Artificial Lungs

    PubMed Central

    Amoako, Kagya A; Montoya, Patrick J; Major, Terry C; Suhaib, Ahmed B; Handa, Hitesh; Brant, David O; Meyerhoff, Mark E; Bartlett, Robert H; Cook, Keith E

    2013-01-01

    Hollow fiber artificial lungs are increasingly being used for long-term applications. However, clot formation limits their use to 1-2 weeks. This study investigated the effect of nitric oxide generating (NOgen) hollow fibers on artificial lung thrombogenicity. Silicone hollow fibers were fabricated to incorporate 50 nm copper particles as a catalyst for NO generation from the blood. Fibers with and without (control) these particles were incorporated into artificial lungs with a 0.1 m2 surface area and inserted in circuits coated tip-to-tip with the NOgen material. Circuits (N=5/each) were attached to rabbits in a pumpless, arterio-venous configuration and run for 4 hrs at an activated clotting time of 350-400s. Three control circuits clotted completely, while none of the NOgen circuits failed. Accordingly, blood flows were significantly higher in the NOgen group (95.9 ± 11.7, p < 0.01) compared to the controls (35.2 ± 19.7) (ml/min), and resistance was significantly higher in the control group after 4 hours (15.38 ± 9.65, p<0.001) than in NOgen (0.09 ± 0.03) (mmHg/mL/min). On the other hand, platelet counts and plasma fibrinogen concentration expressed as percent of baseline in control group (63.7 ± 5.7%, 77.2 ± 5.6% [p<0.05]) were greater than those in the NOgen group (60.4 ± 5.1%, 63.2 ± 3.7%). Plasma copper levels in the NOgen group were 2.8 times baseline at 4 hours (132.8 ± 4.5 μg/dl) and unchanged in the controls. This work demonstrates that NO generating gas exchange fibers could be a potentially effective way to control coagulation inside artificial lungs. PMID:23613156

  9. NuSTAR Observations of the State Transition of Millisecond Pulsar Binary PSR J1023+0038

    NASA Astrophysics Data System (ADS)

    Tendulkar, Shriharsh P.; Yang, Chengwei; An, Hongjun; Kaspi, Victoria M.; Archibald, Anne M.; Bassa, Cees; Bellm, Eric; Bogdanov, Slavko; Harrison, Fiona A.; Hessels, Jason W. T.; Janssen, Gemma H.; Lyne, Andrew G.; Patruno, Alessandro; Stappers, Benjamin; Stern, Daniel; Tomsick, John A.; Boggs, Steven E.; Chakrabarty, Deepto; Christensen, Finn E.; Craig, William W.; Hailey, Charles A.; Zhang, William

    2014-08-01

    We report NuSTAR observations of the millisecond pulsar-low-mass X-ray binary (LMXB) transition system PSR J1023+0038 from 2013 June and October, before and after the formation of an accretion disk around the neutron star. Between June 10 and 12, a few days to two weeks before the radio disappearance of the pulsar, the 3-79 keV X-ray spectrum was well fit by a simple power law with a photon index of Γ =1.17+0.08-0.07 (at 90% confidence) with a 3-79 keV luminosity of 7.4 ± 0.4 × 1032 erg s-1. Significant orbital modulation was observed with a modulation fraction of 36% ± 10%. During the October 19-21 observation, the spectrum is described by a softer power law (Γ =1.66+0.06-0.05) with an average luminosity of 5.8 ± 0.2 × 1033 erg s-1 and a peak luminosity of ≈1.2 × 1034 erg s-1 observed during a flare. No significant orbital modulation was detected. The spectral observations are consistent with previous and current multiwavelength observations and show the hard X-ray power law extending to 79 keV without a spectral break. Sharp-edged, flat-bottomed dips are observed with widths between 30 and 1000 s and ingress and egress timescales of 30-60 s. No change in hardness ratio was observed during the dips. Consecutive dip separations are log-normal in distribution with a typical separation of approximately 400 s. These dips are distinct from dipping activity observed in LMXBs. We compare and contrast these dips to observations of dips and state changes in the similar transition systems PSR J1824-2452I and XSS J1227.0-4859 and discuss possible interpretations based on the transitions in the inner disk.

  10. Observational Study of the Quasi-periodic Fast-propagating Magnetosonic Waves and the Associated Flare on 2011 May 30

    NASA Astrophysics Data System (ADS)

    Shen, Yuandeng; Liu, Yu

    2012-07-01

    On 2011 May 30, quasi-periodic fast-propagating (QFP) magnetosonic waves accompanied by a C2.8 flare were directly imaged by the Atmospheric Imaging Assembly instrument on board the Solar Dynamics Observatory. The QFP waves successively emanated from the flare kernel, they propagated along a cluster of open coronal loops with a phase speed of ~834 km s-1 during the flare's rising phase, and the multiple arc-shaped wave trains can be fitted with a series of concentric circles. We generate the k - ω diagram of the Fourier power and find a straight ridge that represents the dispersion relation of the waves. Along the ridge, we find a lot of prominent nodes which represent the available frequencies of the QFP waves. On the other hand, the frequencies of the flare are also obtained by analyzing the flare light curves using the wavelet technique. The results indicate that almost all the main frequencies of the flare are consistent with those of the QFP waves. This suggests that the flare and the QFP waves were possibly excited by a common physical origin. On the other hand, a few low frequencies (e.g., 2.5 mHz (400 s) and 0.7 mHz (1428 s)) revealed by the k - ω diagram cannot be found in the accompanying flare. We propose that these low frequencies were possibly due to the leakage of the pressure-driven p-mode oscillations from the photosphere into the low corona, which should be a noticeable mechanism for driving the QFP waves observed in the corona.

  11. The Multicenter Aerobic Iron Respiratory Chain of Acidithiobacillus ferrooxidans Functions as an Ensemble with a Single Macroscopic Rate Constant.

    PubMed

    Li, Ting-Feng; Painter, Richard G; Ban, Bhupal; Blake, Robert C

    2015-07-24

    Electron transfer reactions among three prominent colored proteins in intact cells of Acidithiobacillus ferrooxidans were monitored using an integrating cavity absorption meter that permitted the acquisition of accurate absorbance data in suspensions of cells that scattered light. The concentrations of proteins in the periplasmic space were estimated to be 350 and 25 mg/ml for rusticyanin and cytochrome c, respectively; cytochrome a was present as one molecule for every 91 nm(2) in the cytoplasmic membrane. All three proteins were rapidly reduced to the same relative extent when suspensions of live bacteria were mixed with different concentrations of ferrous ions at pH 1.5. The subsequent molecular oxygen-dependent oxidation of the multicenter respiratory chain occurred with a single macroscopic rate constant, regardless of the proteins' in vitro redox potentials or their putative positions in the aerobic iron respiratory chain. The crowded electron transport proteins in the periplasm of the organism constituted an electron conductive medium where the network of protein interactions functioned in a concerted fashion as a single ensemble with a standard reduction potential of 650 mV. The appearance of product ferric ions was correlated with the reduction levels of the periplasmic electron transfer proteins; the limiting first-order catalytic rate constant for aerobic respiration on iron was 7,400 s(-1). The ability to conduct direct spectrophotometric studies under noninvasive physiological conditions represents a new and powerful approach to examine the extent and rates of biological events in situ without disrupting the complexity of the live cellular environment.

  12. Development of a Compact-Sized Falling Needle Rheometer for Measurement of Flow Properties of Fresh Human Blood

    NASA Astrophysics Data System (ADS)

    Yamamoto, Hideki; Kawamura, Kimito; Omura, Kazunobu; Tokudome, Shogo

    2010-12-01

    A compact-sized falling needle rheometer with rapid operation and automatic flow analysis has been developed for viscometry of fresh human blood without anticoagulant. The volume of a fresh blood sample only needs to be 3 mL, and the measuring time is within 2 min after taking a blood sample from the human body. Measured flow properties of human blood are evaluated as a flow curve, that is, the relationship between the shear stress ( τ) and shear rate ( γ). Observed flow curves of fresh human blood show three typical fluid regions, that is, the Casson fluid region for a low shear rate range of 0 < γ > 140 s-1, the transition region for a shear rate near 140 s-1 < γ < 160 s-1, and the Newtonian fluid region for a high shear rate range of 160 s-1 < γ > 400 s-1. Flow properties of human blood such as the yield stress ( τ y) in the Casson fluid region and the apparent viscosity ( μ) in the Newtonian fluid region are measured, and they are compared between male and female blood. It is found that the range of human blood viscosity for males is (5.5 to 6.4) mPa · s, and for females is (4.5 to 5.3) mPa · s. The viscosities of male blood without anticoagulant show higher values than those of female blood. Human blood viscosities with anticoagulant show a lower value than that without anticoagulant. A linear relationship between the hematocrit value, that is, the volume percentage of red corpuscles in the human blood, and the apparent viscosity are observed for both male and female blood. This article is concerned with the flow analysis of fresh human blood viscosity without anticoagulant using a newly developed compact-sized falling needle rheometer.

  13. High-speed analysis of complex indoor VOC mixtures by vacuum-outlet GC with air carrier gas and programmable retention.

    PubMed

    Grall, A J; Zellers, E T; Sacks, R D

    2001-01-01

    A pressure-tunable, series-coupled column ensemble was used with atmospheric pressure air as carrier gas for the vacuum-outlet GC analysis of 42 volatile and semivolatile organic compounds commonly encountered as indoor air pollutants. Separation strategies applicable to a field-portable instrument that will employ a dual-stage preconcentrator and a microsensor array as the detector were developed, where coelution of certain analytes can be tolerated. The capillary column ensemble consists of a 4.5-m segment of nonpolar dimethyl polysiloxane followed by a 7.5-m segment of polar trifluoropropylmethyl polysiloxane. Good long-term thermal stability of the column ensemble was observed for continuous operation in air at temperatures up to 210 degrees C. A computer-driven pressure controller at the column junction point is used to adjust vapor retention for specified sets of target compounds. The compounds were divided into two groups according to retention order, and high-speed analysis conditions were determined for the two groups individually as well as for the entire mixture. The earlier eluting group of 21 compounds was analyzed isothermally at 30 degrees C in about 160 s using a single, on-the-fly junction-point pressure change during the separation. The later eluting group of 21 compounds was analyzed in about 200 s with temperature programming and a constant (tuned) junction-point pressure. The entire mixture was analyzed in about 400 s using a two-step temperature program and a three-step pressure program, with minimal overlap in eluting peaks. Separations are adequate for analysis by a sensor array capable of discriminating among small groups of coeluting vapors on the basis of their response patterns.

  14. Inter-pulse high-resolution gamma-ray spectra using a 14 MeV pulsed neutron generator

    USGS Publications Warehouse

    Evans, L.G.; Trombka, J.I.; Jensen, D.H.; Stephenson, W.A.; Hoover, R.A.; Mikesell, J.L.; Tanner, A.B.; Senftle, F.E.

    1984-01-01

    A neutron generator pulsed at 100 s-1 was suspended in an artificial borehole containing a 7.7 metric ton mixture of sand, aragonite, magnetite, sulfur, and salt. Two Ge(HP) gamma-ray detectors were used: one in a borehole sonde, and one at the outside wall of the sample tank opposite the neutron generator target. Gamma-ray spectra were collected by the outside detector during each of 10 discrete time windows during the 10 ms period following the onset of gamma-ray build-up after each neutron burst. The sample was measured first when dry and then when saturated with water. In the dry sample, gamma rays due to inelastic neutron scattering, neutron capture, and decay were counted during the first (150 ??s) time window. Subsequently only capture and decay gamma rays were observed. In the wet sample, only neutron capture and decay gamma rays were observed. Neutron capture gamma rays dominated the spectrum during the period from 150 to 400 ??s after the neutron burst in both samples, but decreased with time much more rapidly in the wet sample. A signal-to-noise-ratio (S/N) analysis indicates that optimum conditions for neutron capture analysis occurred in the 350-800 ??s window. A poor S/N in the first 100-150 ??s is due to a large background continuum during the first time interval. Time gating can be used to enhance gamma-ray spectra, depending on the nuclides in the target material and the reactions needed to produce them, and should improve the sensitivity of in situ well logging. ?? 1984.

  15. Magnetic field and quadruple Langmuir probe measurements in the plume of the plasmoid thruster experiment

    NASA Astrophysics Data System (ADS)

    Koelfgen, Syri Jo

    The development of high specific impulse rocket engines is essential for fast and efficient space travel. The plasmoid thruster, a novel propulsion concept with the potential for producing a high specific impulse, was investigated in light of this need. This pulsed inductive rocket utilizes the Lorentz force to accelerate plasmoids and produce thrust. The Plasmoid Thruster Experiment (PTX) was designed to experimentally evaluate the thruster concept. PTX operates by producing plasmoids in a conical theta-pinch coil and ejecting them at high velocity. Measurements of the plasmoid magnetic fields, electron temperature (Te), electron number density (n e) and Mach number (M) were taken in the PTX plume with a B˙ probe array and a quadruple Langmuir probe. The measurements were used for calculating exit velocity and Isp. High-speed photographs were also obtained for capturing images of the plasmoids and estimating their velocity. The magnetic field data showed behavior characteristic of plasmoids, such as the occurrence of the maximum axial magnetic field on axis and magnetic field reversal. The quadruple Langmuir probe data revealed several factors that influence thruster operation, including propellant choice, supply pressure and propellant injection timing (tpuff). For Ar propellant at supply pressures of 14--34 psig and tpuff = 2200 mus, Te ranged from 2--7 eV, ne ranged from 1.5 x 1020 m-3 to 3.5 x 1020 m-3, and M ranged from 3.3--3.8 in PTX. For H2 propellant, T e ranged from 15--27 eV, ne ranged from 0.8 x 1020 m-3 to 1.5 x 1020 m-3, and M ranged from 1.4--2.6, for supply pressures of 9--38 psig and tpuff = 1200--2400 mus. Analysis of the plume measurements yielded high thruster exit velocities, indicating that the plasmoid thruster can produce a high Isp. Velocities of 24 km/s, 35 km/s and 46 km/s were calculated for supply pressures of 38 psig, 24 psig and 9 psig of H2 propellant, respectively. These exit velocities deliver Isp values of 2,400 s, 3,500 s and 4

  16. A broadband absorption spectrometer using light emitting diodes for ultrasensitive, in situ trace gas detection

    SciTech Connect

    Langridge, Justin M.; Shillings, Alexander J. L.; Jones, Roderic L.; Ball, Stephen M.

    2008-12-15

    of 0.25 pptv for a 10 s acquisition time, which improves with further signal averaging to 0.09 pptv in 400 s. Finally, an example of the instrument's performance under field work conditions is presented, in this case of measurements of the sum of NO{sub 3}+N{sub 2}O{sub 5} concentrations in the marine boundary layer acquired during the Reactive Halogens in the Marine Boundary Layer field campaign.

  17. A broadband absorption spectrometer using light emitting diodes for ultrasensitive, in situ trace gas detection

    NASA Astrophysics Data System (ADS)

    Langridge, Justin M.; Ball, Stephen M.; Shillings, Alexander J. L.; Jones, Roderic L.

    2008-12-01

    acquisition time, which improves with further signal averaging to 0.09 pptv in 400 s. Finally, an example of the instrument's performance under field work conditions is presented, in this case of measurements of the sum of NO3+N2O5 concentrations in the marine boundary layer acquired during the Reactive Halogens in the Marine Boundary Layer field campaign.

  18. Arne - Exploring the Mare Tranquillitatis Pit

    NASA Astrophysics Data System (ADS)

    Robinson, M. S.; Thangavelautham, J.; Wagner, R.; Hernandez, V. A.; Finch, J.

    2014-12-01

    Lunar mare "pits" are key science and exploration targets. The first three pits were discovered within Selene observations [1,2] and were proposed to represent collapses into lava tubes. Subsequent LROC images revealed 5 new mare pits and showed that the Mare Tranquillitatis pit (MTP; 8.335°N, 33.222°E) opens into a sublunarean void at least 20-meters in extent [3,4]. A key remaining task is determining pit subsurface extents, and thus fully understanding their exploration and scientific value. We propose a simple and cost effective reconnaissance of the MTP using a small lander (<130 kg) named Arne, that carries three flying microbots (or pit-bots) [5,6,7]. Key measurement objectives include decimeter scale characterization of the pit walls, 5-cm scale imaging of the eastern floor, determination of the extent of sublunarean void(s), and measurement of the magnetic and thermal environment. After landing and initial surface systems check Arne will transmit full resolution descent and surface images. Within two hours the first pit-bot will launch and fly into the eastern void. Depending on results from the first pit-bot the second and third will launch and perform follow-up observations. The primary mission is expected to last 48-hours; before the Sun sets on the lander there should be enough time to execute ten flights with each pit-bot. The pit-bots are 30-cm diameter spherical flying robots [5,6,7] equipped with stereo cameras, temperature sensors, sensors for obstacle avoidance and a laser rangefinder. Lithium hydride [5,6] and water/hydrogen peroxide power three micro-thrusters and achieve a specific impulse of 350-400 s. Each pit-bot can fly for 2 min at 2 m/s for more than 100 cycles; recharge time is 20 min. Arne will carry a magnetometer, thermometer, 2 high resolution cameras, and 6 wide angle cameras and obstacle avoidance infrared sensors enabling detailed characterization of extant sublunarean voids. [1] Haruyama et al. (2010) 41st LPSC, #1285. [2

  19. Remote sensing of nitric oxide emissions from planes, trains and automobiles

    NASA Astrophysics Data System (ADS)

    Popp, Peter John

    Remote sensing has been proven as an effective method for measuring in-use mobile source emissions. This document describes the development of a remote sensor for mobile source nitric oxide, based on an instrument previously developed at the University of Denver for measuring carbon monoxide and hydrocarbon emissions. The new remote sensor makes use of a high-speed ultraviolet spectrometer to quantify nitric oxide by absorption spectroscopy at 226 nm in the ultraviolet region. The high-speed spectrometer is coupled to an existing FEAT remote sensor, for the simultaneous measurement of CO, CO2 and hydrocarbons by non-dispersive infrared absorption spectroscopy. The utility of the instrument was demonstrated in the measurement of nitric oxide emissions from automobiles, commercial aircraft, and railroad locomotives. The remote sensor was used to measure nitric oxide emissions from motor vehicles in Chicago in 1997 and 1998, as part of a five-year study to characterize motor vehicle emissions and deterioration in that city. Emissions data were collected for over 19,000 vehicles in 1997 and almost 23,000 vehicles in 1998. All of these records contained valid measurements for carbon monoxide and hydrocarbons, in addition to nitric oxide. In September of 1997, a study was conducted with the cooperation of British Airways and the British Airports Authority to demonstrate the capability of the remote sensor in measuring nitric oxide emissions from in-use commercial aircraft. In two days of sampling at London Heathrow Airport, a total of 122 measurements were made of 90 different aircraft, ranging in size from Gulfstream executive jets to Boeing 747-400s. The measured nitric oxide emission indices were not inconsistent with commercial aircraft emission indices published by the International Civil Aviation Organization. The utility of the remote sensor in measuring nitric oxide emissions from railroad locomotives was demonstrated in January of 1999, in a study conducted with

  20. Effects of soluble flavin on heterogeneous electron transfer between surface-exposed bacterial cytochromes and iron oxides

    NASA Astrophysics Data System (ADS)

    Wang, Zheming; Shi, Zhi; Shi, Liang; White, Gaye F.; Richardson, David J.; Clarke, Thomas A.; Fredrickson, Jim K.; Zachara, John M.

    2015-08-01

    Dissimilatory iron-reducing bacteria can utilize insoluble Fe(Mn)-oxides as a terminal electron acceptor under anaerobic conditions. For Shewanella species specifically, evidence suggests that iron reduction is associated with the secretion of flavin mononucleotide (FMN) and riboflavin. However, the exact mechanism of flavin involvement is unclear; while some indicate that flavins mediate electron transfer (Marsili et al., 2008), others point to flavin serving as co-factors to outer membrane proteins (Okamoto et al., 2013). In this work, we used methyl viologen (MVrad +)-encapsulated, porin-cytochrome complex (MtrCAB) embedded liposomes (MELs) as a synthetic model of the Shewanella outer membrane to investigate the proposed mediating behavior of microbially produced flavins. The reduction kinetics of goethite, hematite and lepidocrocite (200 μM) by MELs ([MVrad +] ∼ 40 μM and MtrABC ⩽ 1 nM) were determined in the presence FMN at pH 7.0 in N2 atmosphere by monitoring the concentrations of MVrad + and FMN through their characteristic UV-visible absorption spectra. Experiments were performed where (i) FMN and Fe(III)-oxide were mixed and then reacted with the reduced MELs and (ii) FMN was reacted with the reduced MELs followed by addition of Fe(III)-oxide. The redox reactions proceeded in two steps: a fast step that was completed in a few seconds, and a slower one lasting over 400 s. For all three Fe(III)-oxides, the initial reaction rate in the presence of a low concentration of FMN (⩽1 μM) was at least a factor of five faster than those with MELs alone, and orders of magnitude faster than those by FMNH2, suggesting that FMN may serve as a co-factor that enhances electron transfer from outer-membrane c-cytochromes to Fe(III)-oxides. The rate and extent of the initial reaction followed the order of lepidocrocite > hematite > goethite, the same as their reduction potentials, implying thermodynamic control on reaction rate. For LEP, with the highest reduction

  1. Technical note: Data loggers are a valid method for assessing the feeding behavior of dairy cows using the Calan Broadbent Feeding System.

    PubMed

    Krawczel, P D; Klaiber, L M; Thibeau, S S; Dann, H M

    2012-08-01

    Assessing feeding behavior is important in understanding the effects of nutrition and management on the well-being of dairy cows. Historically, collection of these data from cows fed with a Calan Broadbent Feeding System (American Calan Inc., Northwood, NH) required the labor-intensive practices of direct observation or video review. The objective of this study was to evaluate the agreement between the output of a HOBO change-of-state data logger (Onset Computer Corp., Bourne, MA), mounted to the door shell and latch plate, and video data summarized with continuous sampling. Data (number of feed bin visits per day and feeding time in minutes per day) were recorded with both methods from 26 lactating cows and 10 nonlactating cows for 3 d per cow (n=108). The agreement of the data logger and video methods was evaluated using the REG procedure of SAS to compare the mean response of the methods against the difference between the methods. The maximum allowable difference (MAD) was set at ±3 for bin visits and ±20 min for feeding time. Ranges for feed bin visits (2 to 140 per d) and feeding time (28 to 267 min/d) were established from video data. Using the complete data set, agreement was partially established between the data logger and video methods for feed bin visits, but not established for feeding time. The complete data set generated by the data logger was screened to remove visits of a duration ≤3 s, reflecting a cow unable to enter a feed bin (representing 7% of all data) and ≥5,400 s, reflecting a failure of the data logger to align properly with its corresponding magnetic field (representing <1% of all data). Using the resulting screened data set, agreement was established for feed bin visits and feeding time. For bin visits, 4% of the data was beyond the MAD. For feeding time, 3% of the data was beyond the MAD and 74% of the data was ±1 min. The insignificant P-value, low coefficient of determination, and concentration of the data within the MAD

  2. Brain responses to nouns, verbs and class-ambiguous words in context.

    PubMed

    Federmeier, K D; Segal, J B; Lombrozo, T; Kutas, M

    2000-12-01

    Recent neuropsychological and imaging data have implicated different brain networks in the processing of different word classes, nouns being linked primarily to posterior, visual object-processing regions and verbs to frontal, motor-processing areas. However, as most of these studies have examined words in isolation, the consequences of such anatomically based representational differences, if any, for the processing of these items in sentences remains unclear. Additionally, in some languages many words (e.g. 'drink') are class-ambiguous, i.e. they can play either role depending on context, and it is not yet known how the brain stores and uses information associated with such lexical items in context. We examined these issues by recording event-related potentials (ERPs) in response to unambiguous nouns (e.g. 'beer'), unambiguous verbs (e. g. 'eat'), class-ambiguous words and pseudowords used as nouns or verbs within two types of minimally contrastive sentence contexts: noun-predicting (e.g. 'John wanted THE [target] but.') and verb-predicting ('John wanted TO [target] but.'). Our results indicate that the nature of neural processing for nouns and verbs is a function of both the type of stimulus and the role it is playing. Even when the context completely specifies their role, word class-ambiguous items differ from unambiguous ones over frontal regions by approximately 150 ms. Moreover, whereas pseudowords elicit larger N400s when used as verbs than when used as nouns, unambiguous nouns and ambiguous words used as nouns elicit more frontocentral negativity than unambiguous verbs and ambiguous words used as verbs, respectively. Additionally, unambiguous verbs elicit a left-lateralized, anterior positivity (approximately 200 ms) not observed for any other stimulus type, though only when these items are used appropriately as verbs (i.e. in verb-predicting contexts). In summary, the pattern of neural activity observed in response to lexical items depends on their general

  3. Conceptual Design, Implementation and Commissioning of Data Acquisition and Control System for Negative Ion Source at IPR

    NASA Astrophysics Data System (ADS)

    Soni, Jignesh; Yadav, Ratnakar; Gahlaut, A.; Bansal, G.; Singh, M. J.; Bandyopadhyay, M.; Parmar, K. G.; Pandya, K.; Chakraborty, A.

    2011-09-01

    Negative ion Experimental facility has been setup at IPR. The facility consists of a RF based negative ion source (ROBIN)—procured under a license agreement with IPP Garching, as a replica of BATMAN, presently operating in IPP, 100 kW 1 MHz RF generators and a set of low and high voltage power supplies, vacuum system and diagnostics. 35 keV 10A H- beam is expected from this setup. Automated successful operation of the system requires an advanced, rugged, time proven and flexible control system. Further the data generated in the experimental phase needs to be acquired, monitored and analyzed to verify and judge the system performance. In the present test bed, this is done using a combination of PLC based control system and a PXI based data acquisition system. The control system consists of three different Siemens PLC systems viz. (1) S-7 400 PLC as a Master Control, (2) S-7 300 PLC for Vacuum system control and (3) C-7 PLC for RF generator control. Master control PLC directly controls all the subsystems except the Vacuum system and RF generator. The Vacuum system and RF generator have their own dedicated PLCs (S-7 300 and C-7 respectively). Further, these two PLC systems work as a slave for the Master control PLC system. Communication between PLC S-7 400, S-7 300 and central control room computer is done through Industrial Ethernet (IE). Control program and GUI are developed in Siemens Step-7 PLC programming software and Wincc SCADA software, respectively. There are approximately 150 analog and 200 digital control and monitoring signals required to perform complete closed loop control of the system. Since the source floats at high potential (˜35 kV); a combination of galvanic and fiber optic isolation has been implemented. PXI based Data Acquisition system (DAS) is a combination of PXI RT (Real time) system, front end signal conditioning electronics, host system and DAQ program. All the acquisition signals coming from various sub-systems are connected and

  4. Statistical development and validation of discharge equations for natural channels

    NASA Astrophysics Data System (ADS)

    Dingman, S. Lawrence; Sharma, Keshav P.

    1997-12-01

    Although the Manning equation is widely accepted as the empirical flow law for rough turbulent open-channel flow, using the equation in practical situations such as slope-area computations is fraught with uncertainty because of the difficulty in specifying the value of the reach resistance, Manning's n. Riggs (1976, J. Res. US Geol. Surv., 4: 285-291) found that n was correlated with water-surface slope, and proposed a multiple-regression equation that obviates the need for estimating n in slope-area estimates of discharge. Because his relation was developed from a relatively small sample ( N = 62), had potential flaws owing to multicollinearity, and was not thoroughly validated, we used an expanded data base ( N = 520) and objective methods to develop a new relation for the same purpose: Q = 1.564 A1.173R0.400S-0.0543log S where Q is discharge (m 3 s -1), A is cross-sectional area (m 2), R is hydraulic radius (m), and S is water-surface slope. We validated Rigg's model and our model using 100 measurements not included in model development and found that both give similar results. Riggs's model is somewhat better in terms of actual (m 3 s -1) error, but ours is better in terms of relative (log Q) error. We conclude that either Riggs's or our model can be used in place of Manning's equation in slope-area computations, but that our model is preferable because it has less bias, minimizes multicollinearity, and performs better when applied to discharge changes in individual reaches. We also found that our model performs better than those of Jarrett (1984, J. Hydraul. Eng., 110: 1519-1539) or Riggs in the range of applicability of Jarrett's equation (0.15 m ≤ R ≤ 2.13 m; 0.002 ≤ S ≤ 0.052). Both Riggs's and our models significantly overestimate Q in flows satisfying both the following conditions: Q < 3 m 3s -1 and Froude number less than 0.2. For other in-bank flows in relatively straight reaches, our model can be recommended for use in slope-area computations

  5. Is 3-Tesla Gd-EOB-DTPA-Enhanced MRI with Diffusion-Weighted Imaging Superior to 64-Slice Contrast-Enhanced CT for the Diagnosis of Hepatocellular Carcinoma?

    PubMed Central

    Maiwald, Bettina; Lobsien, Donald; Kahn, Thomas; Stumpp, Patrick

    2014-01-01

    Objectives To compare 64-slice contrast-enhanced computed tomography (CT) with 3-Tesla magnetic resonance imaging (MRI) using Gd-EOB-DTPA for the diagnosis of hepatocellular carcinoma (HCC) and evaluate the utility of diffusion-weighted imaging (DWI) in this setting. Methods 3-phase-liver-CT was performed in fifty patients (42 male, 8 female) with suspected or proven HCC. The patients were subjected to a 3-Tesla-MRI-examination with Gd-EOB-DTPA and diffusion weighted imaging (DWI) at b-values of 0, 50 and 400 s/mm2. The apparent diffusion coefficient (ADC)-value was determined for each lesion detected in DWI. The histopathological report after resection or biopsy of a lesion served as the gold standard, and a surrogate of follow-up or complementary imaging techniques in combination with clinical and paraclinical parameters was used in unresected lesions. Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were evaluated for each technique. Results MRI detected slightly more lesions that were considered suspicious for HCC per patient compared to CT (2.7 versus 2.3, respectively). ADC-measurements in HCC showed notably heterogeneous values with a median of 1.2±0.5×10−3 mm2/s (range from 0.07±0.1 to 3.0±0.1×10−3 mm2/s). MRI showed similar diagnostic accuracy, sensitivity, and positive and negative predictive values compared to CT (AUC 0.837, sensitivity 92%, PPV 80% and NPV 90% for MRI vs. AUC 0.798, sensitivity 85%, PPV 79% and NPV 82% for CT; not significant). Specificity was 75% for both techniques. Conclusions Our study did not show a statistically significant difference in detection in detection of HCC between MRI and CT. Gd-EOB-DTPA-enhanced MRI tended to detect more lesions per patient compared to contrast-enhanced CT; therefore, we would recommend this modality as the first-choice imaging method for the detection of HCC and therapeutic decisions. However, contrast-enhanced CT was not inferior in our study, so

  6. Conceptual Design, Implementation and Commissioning of Data Acquisition and Control System for Negative Ion Source at IPR

    SciTech Connect

    Soni, Jignesh; Gahlaut, A.; Bansal, G.; Parmar, K. G.; Pandya, K.; Chakraborty, A.; Yadav, Ratnakar; Singh, M. J.; Bandyopadhyay, M.

    2011-09-26

    Negative ion Experimental facility has been setup at IPR. The facility consists of a RF based negative ion source (ROBIN)--procured under a license agreement with IPP Garching, as a replica of BATMAN, presently operating in IPP, 100 kW 1 MHz RF generators and a set of low and high voltage power supplies, vacuum system and diagnostics. 35 keV 10A H- beam is expected from this setup. Automated successful operation of the system requires an advanced, rugged, time proven and flexible control system. Further the data generated in the experimental phase needs to be acquired, monitored and analyzed to verify and judge the system performance. In the present test bed, this is done using a combination of PLC based control system and a PXI based data acquisition system. The control system consists of three different Siemens PLC systems viz. (1) S-7 400 PLC as a Master Control, (2) S-7 300 PLC for Vacuum system control and (3) C-7 PLC for RF generator control. Master control PLC directly controls all the subsystems except the Vacuum system and RF generator. The Vacuum system and RF generator have their own dedicated PLCs (S-7 300 and C-7 respectively). Further, these two PLC systems work as a slave for the Master control PLC system. Communication between PLC S-7 400, S-7 300 and central control room computer is done through Industrial Ethernet (IE). Control program and GUI are developed in Siemens Step-7 PLC programming software and Wincc SCADA software, respectively. There are approximately 150 analog and 200 digital control and monitoring signals required to perform complete closed loop control of the system. Since the source floats at high potential ({approx}35 kV); a combination of galvanic and fiber optic isolation has been implemented. PXI based Data Acquisition system (DAS) is a combination of PXI RT (Real time) system, front end signal conditioning electronics, host system and DAQ program. All the acquisition signals coming from various sub-systems are connected and

  7. NuSTAR observations of the state transition of millisecond pulsar binary PSR J1023+0038

    SciTech Connect

    Tendulkar, Shriharsh P.; Bellm, Eric; Harrison, Fiona A.; Yang, Chengwei; An, Hongjun; Kaspi, Victoria M.; Archibald, Anne M.; Bassa, Cees; Hessels, Jason W. T.; Janssen, Gemma H.; Bogdanov, Slavko; Lyne, Andrew G.; Stappers, Benjamin; Patruno, Alessandro; Stern, Daniel; Tomsick, John A.; Boggs, Steven E.; Craig, William W.; Chakrabarty, Deepto; Christensen, Finn E.; and others

    2014-08-20

    We report NuSTAR observations of the millisecond pulsar-low-mass X-ray binary (LMXB) transition system PSR J1023+0038 from 2013 June and October, before and after the formation of an accretion disk around the neutron star. Between June 10 and 12, a few days to two weeks before the radio disappearance of the pulsar, the 3-79 keV X-ray spectrum was well fit by a simple power law with a photon index of Γ=1.17{sub −0.07}{sup +0.08} (at 90% confidence) with a 3-79 keV luminosity of 7.4 ± 0.4 × 10{sup 32} erg s{sup –1}. Significant orbital modulation was observed with a modulation fraction of 36% ± 10%. During the October 19-21 observation, the spectrum is described by a softer power law (Γ=1.66{sub −0.05}{sup +0.06}) with an average luminosity of 5.8 ± 0.2 × 10{sup 33} erg s{sup –1} and a peak luminosity of ≈1.2 × 10{sup 34} erg s{sup –1} observed during a flare. No significant orbital modulation was detected. The spectral observations are consistent with previous and current multiwavelength observations and show the hard X-ray power law extending to 79 keV without a spectral break. Sharp-edged, flat-bottomed dips are observed with widths between 30 and 1000 s and ingress and egress timescales of 30-60 s. No change in hardness ratio was observed during the dips. Consecutive dip separations are log-normal in distribution with a typical separation of approximately 400 s. These dips are distinct from dipping activity observed in LMXBs. We compare and contrast these dips to observations of dips and state changes in the similar transition systems PSR J1824–2452I and XSS J1227.0–4859 and discuss possible interpretations based on the transitions in the inner disk.

  8. Abnormal N400 word repetition effects in fragile X-associated tremor/ataxia syndrome

    PubMed Central

    Chan, Shiaohui; Wong, Ling M.; Schneider, Andrea; Seritan, Andreea; Niese, Adam; Yang, Jin-Chen; Laird, Kelsey; Teichholtz, Sara; Khan, Sara; Tassone, Flora; Hagerman, Randi

    2010-01-01

    .04 for group effect). Reduced P600 repetition effect amplitude was associated with poorer recall within fragile X-associated tremor/ataxia syndrome patients (r = 0.66) and across all subjects (r = 0.52). Larger P600 amplitude to new congruous words also correlated significantly with higher free recall scores (r = 0.37, P < 0.01) across all subjects. We found a correlation between the amplitude of late positivity and CGG repeat length in those with fragile X-associated tremor/ataxia syndrome (r = 0.47, P = 0.006). Higher levels of FMR1 mRNA were associated with smaller N400s to incongruous words and larger positive amplitudes (between 300 and 500 ms) to congruous words. In conclusion, event-related potential word repetition effects appear sensitive to the cognitive dysfunction present in patients with mild fragile X-associated tremor/ataxia syndrome. Their more severe reduction in N400 repetition effect, than P600, is in contrast to the reverse pattern reported in amnestic mild cognitive impairment and incipient Alzheimer’s disease (Olichney et al., 2008). PMID:20410144

  9. The interannual earthquake distributions and its peculiarity.

    NASA Astrophysics Data System (ADS)

    Levin, Boris; Sasorova, Elena

    2010-05-01

    samples with "shallow" EQ. But the null hypothesis was confirmed for "deep" earthquakes. We use the Chi-Square test for well-filled sequences (no less than 5 events in each discrete interval) and the method of statistical testing (Monte-Carlo) for poor-filled sequences. The average probability (Psp), that EQ distributions of the"shallow" events are nonuniform is equal to 0.975 (for all subregions and all magnitude levels), but for the deep events the Psp value is equal to 0.65. It was used 184 samples for analysis (more than 200000 events). The noticeable increase of the EQ number in short time intervals as a rule two times in year, and significant reducing of seismic activity in the rest part of the year was observed. It was shown, that the main maximum of the seismic activity take place in December-February (minimum of the Earth-Sun distance) for both Hemispheres (southern and northern) and the minimum - in April (minimum of the Earth rotation speed). The position of the seismic activity peak depends on the latitudinal location of the investigated subregion. For the some near-equatorial subregions the maximum of the seismic activity shifted to the autumn. The stability of the within year distribution for shorter periods of observations (10, 5 years) was proved. If the within-year variability exists, then occurrence of the seismic events depends on the position of the Earth -Moon system on ecliptic plane or on factors that are varied during motion of the Earth-Moon system along ecliptic plane Then we let vary the Htr value by using special software procedure from 20 up to 300 km for searching the optimal Htr value (Hopt). The Hopt lets us to make the cluster decomposition whole set of seismic events in every subregion in two nonoverlapping subsets. It was found, that the Hopt boundary between the "shallow" and the "deep" events for the most subregions was arranged in deep 50-80 km. But the Hopt value may shifted to 120 -160 km for latitude belt 100 - 400 S. Thus the EQs