text:
EM Sounding Characterization of Soil Environment toward Estimation of Potential Pollutant Load from Non-point Sources
NASA Astrophysics Data System (ADS)
Mori, Y.; Ide, J.; Somura, H.; Morisawa, T.
A multi-frequency electro-magnetic (EM) sounding method was applied to agriculture fields to investigate the characteristics of non-point pollution load. Soil environmental properties such as differences in land management were analyzed with electrical conductivity (EC) maps. In addition, vertical EC profiles obtained from EM soundings were compared with EC in drainage ditch or river water. As results, surface soil EC maps successfully extracted the differences in land management affected by fertilizer application. Moreover, surface EC at the vertical profiles strongly related with drainage ditch or river EC, showing most of the EC in the water was explained by surface EC maps at the EM sounding data. The proposed method has strength in obtaining EC data without sampling river water, the situation we sometimes experienced at the field survey.
Magnetotelluric Sensor Development for Planetary Subsurface Exploration
NASA Astrophysics Data System (ADS)
Fuqua, H.; Delory, G. T.; De Pater, I.; Grimm, R. E.
Electromagnetic (EM) Sounding is a powerful geophysical investigation technique capable of constraining planetary subsurface structure, including core size, mantle and crustal temperature profiles, and the distribution of electrical conductivity at depth. Natural sources of EM activity, including solar wind turbulence and plasma waves, can induce electric and magnetic fields in the Moon and other small bodies. These induced fields respond according to the electrical conductivity as a function of skin depth of the body in question. In a branch of EM Sounding known as Magnetotellurics (MT), measurements of the horizontal electric and magnetic fields at the planetary surface are inverted to produce constraints on the interior. MT is particularly worthwhile in that geophysically meaningful results can be obtained from a single station, thus avoiding network mission architectures. While surface magnetic field measurements were taken on the Moon during the Apollo era, to date no measurements of the surface horizontal electric field have been attempted. However electric field measurements on the lunar surface should be feasible given their long successful history on spacecraft missions in similar environments. Building upon the heritage of electric field sensor technology at the UC Berkeley Space Sciences Laboratory, we describe a development plan for this instrument from component level to a fully functional instrument assembly for use in EM sounding, highlighting operational requirements, science capabilities, required testing, anticipated results and challenges to overcome. Upon development, this lander electric field sensor will enable future MT surveys on the Moon, and will provide a new exploration method for other small airless bodies from a single station.
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.
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.
Multi-frequency electromagnetic sounding tool EMS. Archaeological discoveries. Case stories.
NASA Astrophysics Data System (ADS)
Abu Zeid, N.; Balkov, E.; Chemyakina, M.; Manstein, A.; Manstein, Y.; Morelli, G.; Santarato, G.
EMS is the new patented tool for shallow-depth (up to 7 m) induction frequency sounding. The tool is developed in Institute of Geophysics, Siberian Branch of Russian Academy, Novosibirsk, RUSSIA. Few years of application of EMS prototypes in archaeological prospection gave us the well described picture of possibilities and limitations of EM sounding for archaeological purpose. We would like to present several archaeological case stories including paleolitic, bronze and iron ages, antique and medieval targets discovery. The cases include complex geophysical works using GPR, Vertical DC sounding and magnetometry together with EM sounding. Archaeological proofs of geophysical prospection will be presented. The last September in Italy we have done the comparative work at few Italian archaeological sites. The second EMS prototype has been compared with commercially available tools for EM prospection such as EM mappers, georadars and DC electrical resistivity tomography. In the comparison EMS feature good noise immunity, high sensibility and resolution. In some cases only EMS data shows the buried targets and it was proved immediately by excavation. The researches were done with financial support of RFBR grant # 00-06-80421
Electromagnetic soundings for geothermal resources in Dixie Valley, Nevada
Wilt, M.J.; Goldstein, N.E.
An electromagnetic (EM) sounding survey was performed over a region encompassing the Dixie Valley geothermal field to map the subsurface resistivity in the geothermal field and the surrounding area. The EM survey, consisting of 19 frequency-domain depth soundings made with the LBL EM-60 system, was undertaken to explore a narrow region adjacent to the Stillwater Range to a depth of 2 to 3 km. Lithologic and well log resistivity information from well 66-21 show that for EM interpretation the section can be reduced to a three-layer model consisting of moderately resistive alluvial sediments, low resistivity lacustrine sediments, and high resistivity Tertiary volcanics and older rocks. This three layer model was used as a starting point in interpreting EM sounding data. Variations in resistivity and thickness provided structural information and clues to the accumulation of geothermal fluids. The interpreted soundings reveal a 1 to 1.5-km-deep low-resistivity zone spatially associated with the geothermal field. The shallow depth suggests that the zone detected is either fluid leakage or hydrothermal alteration, rather than high-temperature reservoir fluids. The position of the low-resistivity zone also conforms to changes in depth to the high resistivity basal layer, suggesting that faulting is a control on the location of productive intervals. 10 refs., 7 figs.
Probabilistic modeling of financial exposure to flood in France
NASA Astrophysics Data System (ADS)
Moncoulon, David; Quantin, Antoine; Leblois, Etienne
CCR is a French reinsurance company which offers natural catastrophe covers with the State guarantee. Within this framework, CCR develops its own models to assess its financial exposure to floods, droughts, earthquakes and other perils, and thus the exposure of insurers and the French State. A probabilistic flood model has been developed in order to estimate the financial exposure of the Nat Cat insurance market to flood events, depending on their annual occurrence probability. This presentation is organized in two parts. The first part is dedicated to the development of a flood hazard and damage model (ARTEMIS). The model calibration and validation on historical events are then described. In the second part, the coupling of ARTEMIS with two generators of probabilistic events is achieved: a stochastic flow generator and a stochastic spatialized precipitation generator, adapted from the SAMPO model developed by IRSTEA. The analysis of the complementary nature of these two generators is proposed: the first one allows generating floods on the French hydrological station network; the second allows simulating surface water runoff and Small River floods, even on ungauged rivers. Thus, the simulation of thousands of non-occured, but possible events allows us to provide for the first time an estimate of the financial exposure to flooding in France at different scales (commune, department, country) and from different points of view (hazard, vulnerability and damages).
Swift and CBA Observations of TT Ari on 2009 October 16
NASA Astrophysics Data System (ADS)
Mukai, Koji; Patterson, Joe; Koff, Bob; Morelle, Etienne; Stein, William; Oksanen, Arto
We observed the nova-like cataclysmic variable (CV) TT Ari, which is currently undergoing a fading episode, with Swift between 2009 October 16 01:31 UT and 09:02 UT. The X-ray telescope (XRT) was operated in photon counting mode and accumulated 4,400 s of good exposure during this interval. The UV/optical telescope (UVOT) was used with the U filter in imaging mode, with an integration time also of 4,400 s.
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.
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.
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.
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.
Quantifiers More or Less Quantify On-Line: ERP Evidence for Partial Incremental Interpretation
ERIC Educational Resources Information Center
Urbach, Thomas P.; Kutas, Marta
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…
Distinguishing lexical- versus discourse-level processing using event-related potentials
Huang, Yi Ting; Hopfinger, Joseph; Gordon, Peter C.
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
Low-Frequency Electromagnetic Sounding for Planetary Volatiles (Invited)
NASA Astrophysics Data System (ADS)
Grimm, R. E.
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
Power Packaging of Spray-Cooled SiC Devices for High Temperature and High Voltage Operation: Final Report
compared with the traditional ferrite and Litz wire structures to provide an order of magnitude increase in power density. System Description Fig. 3.12...VxFR.s; Channel 4: Lc, Stop. . . - - I Chi 25.0V Ch2 2S30V M40.0S A Ch2 ŗ. SSO5V (11 200ooV SM 1VOOAQ I2jun 2001 0 31.40% S1:32:41 Fig. 4.14
VizieR Online Data Catalog: Variable stars in the field of Andromeda XXV. III. (Cusano+, 2016)
NASA Astrophysics Data System (ADS)
Cusano, F.; Garofalo, A.; Clementini, G.; Cignoni, M.; Federici, L.; Marconi, M.; Ripepi, V.; Musella, I.; Testa, V.; Carini, R.; Faccini, M.
A total of 85 B and 87 V images, each of 400s exposure, were obtained with the Large Binocular Cameras (LBC) of the Large Binocular Telescope (LBT) of a region of 23'x23' centered on And XXV (RA=00:30:08.9, DEC=+46:51:07, J2000.0) from the 18th to the 24th of 2011 October. (2 data files).
Changes in fatty acids composition during seed growth and physicochemical characteristics of oil extracted from four safflower cultivars.
Rahamatalla, A B; Babiker, E E; Krishna, A G; El Tinay, A H
Fatty acid contents at different stages of maturity and physicochemical characteristics of oil extracted from mature seeds of four safflower cultivars (S208, S400, S541, and S303) were studied. Results indicated that for all cultivars both saturated and unsaturated fatty acid contents fluctuated with seed growth and development. Palmitic acid content decreased up to day 20 after which it started to increase for the S400, S541, and S303 cultivars, while for S208 it progressively decreased. Stearic acid fluctuated with seed growth and development. Oleic acid showed slight changes with seed growth and development, while linoleic acid decreased with seed growth and development for the S400, S541, and S303 cultivars while for S208 after day 30, it started to increase significantly. For all cultivars, glyceride contents varied among the cultivars with maximum values of 97.70, 2.80 and 0.20 for tri-, di- and monoglycerides, respectively. Physicochemical investigation of mature seed oils showed that the color, density, refractive index, free fatty acids, peroxide value, saponification value and unsaponifiable matter were similar for all cultivars while viscosity, iodine value, and acetone insoluble matter varied among the cultivars.
Lexical Selection Differences between Monolingual and Bilingual Listeners
Friesen, Deanna C.; Chung-Fat-Yim, Ashley; Bialystok, Ellen
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
Lexical selection differences between monolingual and bilingual listeners.
Friesen, Deanna C; Chung-Fat-Yim, Ashley; Bialystok, Ellen
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.
Effects of a small dose of olanzapine on healthy subjects according to their schizotypy: an ERP study using a semantic categorization and an oddball task.
Debruille, J Bruno; Rodier, Mitchell; Prévost, Marie; Lionnet, Claire; Molavi, Siamak
Delusions and hallucinations are often meaningful. They thus reveal abnormal semantic activations. To start testing whether antipsychotics act by reducing abnormal semantic activations we focused on the N400 event-related brain potential, which is elicited by meaningful stimuli, such as words, and whose distribution on the scalp is known to depend on the semantic category of these stimuli. We used a semantic-categorization task specially designed to reduce the impact of the variations of context processing across subjects' groups and a classical oddball task as a control. Healthy subjects were recruited rather than psychotic patients to ensure that the medication effects could not be secondary to a reduction of symptoms. These participants (n=47) were tested in a double-blind cross-over paradigm where the ERP effects of 2.5mg of olanzapine taken on the eve of the testing were compared to those of the placebo. The amplitudes of the N400s elicited by the target words were greater at anterior scalp sites in the half of the subjects having higher schizotypal scores. Olanzapine reduced these larger N400s and had no effect on the small anterior N400s of the half of the subjects with lower scores. These results are discussed as consistent with the idea that antipsychotics reduce abnormal activations of particular semantic representations. Further studies should thus be done to see if this reduction correlates with and predicts the decrease of psychotic symptoms in patients.
Integrated interpretation of overlapping AEM datasets achieved through standardisation
NASA Astrophysics Data System (ADS)
Sørensen, Camilla C.; Munday, Tim; Heinson, Graham
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.
New Geophysical Data On The Remains of Ancient Buildings In The Vicinity of Kazan Kremlin (russia)
NASA Astrophysics Data System (ADS)
Slepak, Z.
Beside the Kremlin of Kazan, a monument of culture and architecture of the 16th-18th centuries, there were many other buildings near the historical territory of the Kremlin which are now partly or wholly destroyed, such as the Bogoroditsky nunnery. New geophysical and archaeological studies have been conducted here in 2000-01 to locate the position of the buildings more precisely. The main geophysical method employed was electromagnetic sounding by the stabilisation of EM-field using the device SIm- & cedil;pulseAuto M-1/0-20T for studying the upper geological layers including the daylight surface. EM-sounding with sampling intervals of 0.5-2.0 m resulted in vertical sec- tions of total electrical conductivity S(H). At some points, high-precision gravimeter survey was also conducted. Subsequent archaeological excavations completely con- firmed the acquired geophysical information and its interpretation. Among the studied objects within the KremlinSs boundary were the bell tower of the Blagoveschensky Cathedral, fortress wall of the 12th century and remains of the KhanSs Palace. The re- mains of the destroyed Our Lady Summer Cathedral, tower and the nunnerySs fence were found in the Bogoroditsky nunnery.
High-Frequency and Very-high-Frequency (HF&VHF) above-groundelectromagnetic impedance measurements
Frangos, William; Becker, Alex; Lee, K.H.
We have field-tested an apparatus for measuring the electromagnetic impedance above the ground at a plurality of frequencies in the 0.3 - 30 MHz range. This window in the frequency spectrum, which lies between frequencies used for GPR and those used for conventional loop-loop EM soundings, has not been used because of difficulties in fielding equipment for making absolute and accurate measurements. Model and physical parameter studies however confirm that data in this frequency band can be used to construct high-resolution maps of electrical conductivity and permittivity of near-surface material. Our equipment was assembled using commercial electric and magnetic antennas. The magnetic loop source is excited by a conventional signal generator - power amplifier assembly. Signal detection is accomplished using RF lock-in amplifiers. All system elements are appropriately isolated by optic - fiber links. We estimate a measurement accuracy of about {+-} 10% for an 8-m separation between source and detector. Field tests were done at the University of California Richmond Field Station where the near surface electrical structure is well known. The experimental data at this site are mainly a function of electrical conductivity. In this context, we have obtained good agreement with the known local variations in resistivity both with depth and with position along a 35-m traverse. Additional tests in more resistive regimes where dielectric permittivity is not negligible yield spectral data compatible with the less well known near-surface electrical properties.
Comparison of dipole-dipole resistivity and electromagnetic induction sounding over the Panther Canyon thermal anomaly, Grass Valley, Nevada
Wilt, M.; Beyer, J.H.; Goldstein, N.E.
A comparison is made between the dipole-dipole resistivity method and electromagnetic sounding method based on surveys over a geothermal anomaly near Panther Canyon, Grass Valley, Nevada. Dipole-dipole data were taken in conjunction with large-scale geothermal studies in the area. Two orthogonal lines were measured over the heat flow anomaly and two-dimensional modeling was performed on the data. EM sounding data were taken with the Lawrence Berkeley Laboratory EM-60 system which is a large-moment, frequency-domain, horizontal-loop system. Relative to single 50-meter-radius transmitter coil, eight soundings were made with detectors at distances of 0.5 to 1.6 km from the loop. Interpreted results from the two surveys indicate substantial agreement in the depth to and thickness of a conductive zone that may be associated with the thermal anomaly. The dipole-dipole method is inherently better for resolving resistive basement beneath the conductive anomaly, and dc resistivity interpretation techniques are presently better to handle the complex two-dimensional geology. However, the EM method is far less labor intensive, requiring only one-third the field time for similar areal coverage.
The basement structure below the peat-lignite deposit in the Philippi sub-basin (Northern Greece) inferred by electromagnetic and magnetic methods
NASA Astrophysics Data System (ADS)
Gurk, M.; Tougiannidis, N.; Oikonomopoulos, I. K.; Kalisperi, D.
During 2009 and 2010 electromagnetic (EM) soundings and a high-resolution magnetic survey were conducted to study the deeper structure of the peat-lignite deposit in the Philippi sub-basin in Northern Greece. The primary intention of investigating the basement structure of the Philippi sub-basin is to propose the ideal location for a deep and continuous paleoclimate drill site. Data were collected along a 12 km transect (NNE-SSW) through the largest extension of the basin from Krinides at the North to Eleftheroupolis at the South. We used a combined set of Radiomagnetotelluric (RMT), Time Domain Electromagnetic (TEM) and Audiomagnetotelluric (AMT) soundings to derive a 2D model of the electrical resistivity distribution versus depth using a joint inversion approach. This model was then cross correlated with a 2D forward model of magnetic anomaly data. The magnetic survey detected strong anomalies in the North that appeared to have been generated by the Philippi granitoid pluton. All three individual data sets support each other and have jointly been analyzed. From this study we yield an asymmetric graben model of the basin structure that shows maximum thickness (ca. 500 m) in the northern part of the basin leading to a reduction of the thickness to the South. The interface between the basin fill and the bedrock ascend steeply in the North. The overall assessment of the deeper basin structure reveals a detachment system that is in good accordance with previous findings.
Chondroprotective supplementation promotes the mechanical properties of injectable scaffold for human nucleus pulposus tissue engineering.
Foss, Berit L; Maxwell, Thomas W; Deng, Ying
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.
A Serine-Substituted P450 Catalyzes Highly Efficient Carbene Transfer to Olefins In Vivo
Coelho, Pedro S.; Wang, Z. Jane; Ener, Maraia E.; Baril, Stefanie A.; Kannan, Arvind A.; Arnold, Frances H.; Brustad, Eric M.
Genetically encoded catalysts for non-natural chemical reactions will open new routes to sustainable production of chemicals. We designed a unique serine-heme ligated cytochrome "P411" that catalyzes efficient and selective carbene transfers from diazoesters to olefins in intact Escherichia coli cells. The mutation C400S in cytochrome P450BM3 gives a signature ferrous-CO Soret peak at 411 nm, abolishes monooxygenation activity, raises the resting state FeIII/II reduction potential, and significantly improves NAD(P)H-driven cyclopropanation activity. PMID:23792734
Moisture Effects on the High Strain-Rate Behavior of Sand (Preprint)
o r s o s dtl c εε 2 (6) The striker, incident and transmission bars in Fig. 1 were fabricated of VM C350 maraging steel (HRC = 53) with a yield...strain-rate of 400 s-1. The sand specimen confined in a hardened steel tube, had a dry density of 1.50 g/cm3 with moisture contents varied from 3% to 20... steel tube with steel wafers placed on both sides of the specimen. The primary focus was to evaluate the effects of saturation levels on the material
Contingency Contracting Officers: Can They Adequately Support the Force?
Conflicts Air Force Institute of Technology, Wright-Patterson AFB, OH, September 1988. 10. Radin, HAJ Sara R ., Contingency Contracting, A Force Multiplier...public release; distribution is unlimited. 4 Performing Organisation Report Number(s) 5 Monitoring organization Report Number(s) a Mass of Performing...7b Address v.t . and Z"co4e1Monery A 13943-50 Monterey CA 934-5000 Monterey CA 40_0 s Naume of Funding/Sponsoring Sb Office Symbol 9 Procurement
A serine-substituted P450 catalyzes highly efficient carbene transfer to olefins in vivo.
Coelho, Pedro S; Wang, Z Jane; Ener, Maraia E; Baril, Stefanie A; Kannan, Arvind; Arnold, Frances H; Brustad, Eric M
Whole-cell catalysts for non-natural chemical reactions will open new routes to sustainable production of chemicals. We designed a cytochrome 'P411' with unique serine-heme ligation that catalyzes efficient and selective olefin cyclopropanation in intact Escherichia coli cells. The mutation C400S in cytochrome P450(BM3) gives a signature ferrous CO Soret peak at 411 nm, abolishes monooxygenation activity, raises the resting-state Fe(III)-to-Fe(II) reduction potential and substantially improves NAD(P)H-driven activity.
High Power Josephson Effect Sources
large spacing was nsed ,along with cooling water, os Iao a d$ to ensure the substrate temperature did not rise durn theCox flow Osiltr.adsaljnto ry~ h m...Here two arra's. a 400 s.m Josephson effect detector and an SIS mixer are "I integrated on a single silicon substrate . One array func- tions as the...junction's shunt resistor, on array's output power and detector's current- voltage characteristics are also discussed. I. INTRODUCTION - U Phb &z locked
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
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
VETEM -- a very early time electromagnetic system -- year 2
Pellerin, L.; Pfeifer, M.C.; Labson, V.F.
In electrically conductive conditions common in environmental characterization studies the minimum depth of investigation for traditional electromagnetic (EM) sounding techniques is roughly 5 meters, while ground penetrating radar (GPR) systems often investigate no more than the top meter or so when clay minerals are present in the soil. Bridging this gap is essential to the characterization of buried waste, contaminant plumes, and other environmental and hydrogeological targets located in the shallow subsurface. The Very Early Time Electromagnetic (VETEM) system is designed to ascertain the conductivity and dielectric properties of the shallow subsurface in conductive terrain. Hence, the one-dimensional (1-D) and three-dimensional (3-D) numerical modeling algorithms, developed in the first year of the project, contain the full solution to the EM problem including both displacement and conduction currents. The VETEM system fills a gap between EM and GPR, but all three methods are necessary to successfully image the shallow subsurface. To achieve the goal of fully 3-D subsurface imaging, the VETEM project is hosting the Electromagnetic Integrated Demonstration (EMID) at the Idaho National Engineering Laboratory`s Cold Test Pit (INEL`s CTP). Over a dozen EM systems will acquire data over the same survey area for interpretation in conjunction with the VETEM team. The prototype time-domain instrument employs a magnetic dipole transmitter and receiver and operates from 10 nano-second to a micro-second. The USGS high frequency sounder (HFS), which served as the VETEM proof-of-concept, uses the same antenna geometry as the time-domain instrument and acquires data from 30 kHz to 30 MHz. The first VETEM survey was recently conducted at the INEL`s CTP as a part of the EMID. The electromagnetic migration technique is being investigated for interpretation of the VETEM data.
Electromagnetic soundings over a geothermal reservoir in Dixie Valley, Nevada
Wilt, M.J.; Goldstein, N.E.
An electromagnetic (EM) sounding survey was performed over a region encompassing the Dixie Valley geothermal field with the purpose of mapping the subsurface resistivity in the geothermal field and its surroundings. The EM survey consisted of 19 frequency-domain depth soundings made with the EM-60 system using three separate horizontal-loop transmitters, and was designed to explore a narrow region adjacent to the Stillwater Range to a depth of 2 to 3 k. Most sounding curves could be fitted to three-layer resistivity models. The surface layer is moderately conductive (10 to 15 ohm-m), has a maximum thickness of 500 m, and consists mainly of alluvial fan and lake sediments. More conductive zones are associated with hydrothermally altered rocks; a resistivity high may be associated with siliceous hot spring deposits. The conductive second layer (2 to 5 ohm-m) varies in thickness from 400 to 800 m and thickens toward the center of the valley. This layer probably consists of lacustrine sediments saturated with saline waters. Local resistivity lows observed in the second layer may be related to elevated subsurface temperatures. This layer may act as a cap rock for the geothermal system. Resistivities of the third layer are high (50 to 100 ohm-m) except in a narrow 5-km band paralleling the range front. This low-resistivity zone, within volcanic rocks, correlates well in depth and location with reported zones of geothermal fluid production. It also seems to correlate with the western margin of a concealed graben structure previously inferred from other geophysical data.
Conflicts in language processing: a new perspective on the N400-P600 distinction.
Frenzel, Sabine; Schlesewsky, Matthias; Bornkessel-Schlesewsky, Ina
Conflicts in language processing often correlate with late positive event-related brain potentials (ERPs), particularly when they are induced by inconsistencies between different information types (e.g. syntactic and thematic/plausibility information). However, under certain circumstances, similar sentence-level interpretation conflicts (inanimate subjects) engender negativity effects (N400s) instead. The present ERP study was designed to shed light on this inconsistency. In previous studies showing monophasic positivities (P600s), the conflict was irresolvable and induced via a verb, whereas N400s were elicited by resolvable, argument-induced conflicts. Here, we therefore examined irresolvable argument-induced conflicts (pronoun case violations) in simple English sentences. Conflict strength was manipulated via the animacy of the first argument and the agreement status of the verb. Processing conflicts engendered a biphasic N400-late positivity pattern, with only the N400 sensitive to conflict strength (animacy). These results suggest that argument-induced conflicts engender N400 effects, (which we interpret in terms of increased competition for the Actor role) whereas irresolvable conflicts elicit late positivities (which we interpret as reflecting well-formedness categorisation).
Second Language Acquisition of Gender Agreement in Explicit and Implicit Training Conditions: An Event-Related Potential Study
Morgan-Short, Kara; Sanz, Cristina; Steinhauer, Karsten; Ullman, Michael T.
This study employed an artificial language learning paradigm together with a combined behavioral/event-related potential (ERP) approach to examine the neurocognition of the processing of gender agreement, an aspect of inflectional morphology that is problematic in adult second language (L2) learning. Subjects learned to speak and comprehend an artificial language under either explicit (classroomlike) or implicit (immersionlike) training conditions. In each group, both noun-article and noun-adjective gender agreement processing were examined behaviorally and with ERPs at both low and higher levels of proficiency. Results showed that the two groups learned the language to similar levels of proficiency but showed somewhat different ERP patterns. At low proficiency, both types of agreement violations (adjective, article) yielded N400s, but only for the group with implicit training. Additionally, noun-adjective agreement elicited a late N400 in the explicit group at low proficiency. At higher levels of proficiency, noun-adjective agreement violations elicited N400s for both the explicit and implicit groups, whereas noun-article agreement violations elicited P600s for both groups. The results suggest that interactions among linguistic structure, proficiency level, and type of training need to be considered when examining the development of aspects of inflectional morphology in L2 acquisition. PMID:21359123
Close, but no garlic: Perceptuomotor and event knowledge activation during language comprehension
Amsel, Ben D.; DeLong, Katherine A.; Kutas, Marta
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
Second Language Acquisition of Gender Agreement in Explicit and Implicit Training Conditions: An Event-Related Potential Study.
Morgan-Short, Kara; Sanz, Cristina; Steinhauer, Karsten; Ullman, Michael T
This study employed an artificial language learning paradigm together with a combined behavioral/event-related potential (ERP) approach to examine the neurocognition of the processing of gender agreement, an aspect of inflectional morphology that is problematic in adult second language (L2) learning. Subjects learned to speak and comprehend an artificial language under either explicit (classroomlike) or implicit (immersionlike) training conditions. In each group, both noun-article and noun-adjective gender agreement processing were examined behaviorally and with ERPs at both low and higher levels of proficiency. Results showed that the two groups learned the language to similar levels of proficiency but showed somewhat different ERP patterns. At low proficiency, both types of agreement violations (adjective, article) yielded N400s, but only for the group with implicit training. Additionally, noun-adjective agreement elicited a late N400 in the explicit group at low proficiency. At higher levels of proficiency, noun-adjective agreement violations elicited N400s for both the explicit and implicit groups, whereas noun-article agreement violations elicited P600s for both groups. The results suggest that interactions among linguistic structure, proficiency level, and type of training need to be considered when examining the development of aspects of inflectional morphology in L2 acquisition.
Coronary artery bypass surgery with heparin-coated perfusion circuits and low-dose heparinization
Mullen, John C.; Bentley, Michael J.; Gelfand, Elliot T.; Koshal, Arvind; Modry, Dennis L.; Guenther, Craig R.; Etches, Wai S.; Stang, Linda J.; Lopushinsky, Steven R.
Objective To evaluate the safety and efficacy of heparin-coated perfusion circuits with low-dose heparinization and centrifugal pumping compared with the standard method during coronary artery bypass grafting. Design Prospective, randomized, single-blind clinical trial. Setting A primary care institution. Patients Ninety patients who underwent first-time elective coronary artery bypass grafting were eligible for the study. After giving informed consent, they were randomly assigned to 1 of 3 groups (30/group). Interventions Perfusion on regular uncoated bypass equipment with a roller pump and full-dose heparinization (300 IU/kg bolus, activated clotting time [ACT] > 400 s) (group 1), on a heparin-coated oxygenator with a centrifugal pump and full-dose heparinization (group 2) and on fully heparin-coated bypass equipment with a centrifugal pump and low-dose heparinization (100 IU/kg bolus, ACT of 180–400 s) (group 3). Standard coronary artery bypass grafting was performed. Outcome measures Postoperative bleeding, transfusion requirements and clinical outcomes. Results There were no complications related to the study protocol. Study groups were similar in terms of postoperative bleeding, transfusion requirements and clinical outcomes. Conclusions Heparin-coated cardiopulmonary bypass with low-dose heparinization and centrifugal pumping is a safe practice but showed no advantages over the use of regular uncoated bypass circuits for coronary bypass surgery. PMID:12067167
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
Yonemitsu, Takafumi; Kawai, Nobuyuki; Sato, Morio Sonomura, Tetsuo; Takasaka, Isao; Nakai, Motoki; Minamiguchi, Hiroki; Sahara, Shinya; Iwasaki, Yasuhiro; Naka, Toshio; Shinozaki, Masahiro
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.
Quantifiers more or less quantify online: ERP evidence for partial incremental interpretation
Urbach, Thomas P.; Kutas, Marta
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
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
]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
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
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
Morphological Properties of Slender Ca ii H Fibrils Observed by Sunrise II
NASA Astrophysics Data System (ADS)
Gafeira, R.; Lagg, A.; Solanki, S. K.; Jafarzadeh, S.; van Noort, M.; Barthol, P.; Blanco Rodríguez, J.; del Toro Iniesta, J. C.; Gandorfer, A.; Gizon, L.; Hirzberger, J.; Knölker, M.; Orozco Suárez, D.; Riethmüller, T. L.; Schmidt, W.
We use seeing-free high spatial resolution Ca ii H data obtained by the Sunrise observatory to determine properties of slender fibrils in the lower solar chromosphere. In this work we use intensity images taken with the SuFI instrument in the Ca ii H line during the second scientific flight of the Sunrise observatory to identify and track elongated bright structures. After identification, we analyze theses structures to extract their morphological properties. We identify 598 slender Ca ii H fibrils (SCFs) with an average width of around 180 km, length between 500 and 4000 km, average lifetime of ≈400 s, and average curvature of 0.002 arcsec‑1. The maximum lifetime of the SCFs within our time series of 57 minutes is ≈2000 s. We discuss similarities and differences of the SCFs with other small-scale, chromospheric structures such as spicules of type I and II, or Ca ii K fibrils.
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
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.
Evidence for an Early High-Energy Afterglow Observed with BATSE from GRB 980923
NASA Technical Reports Server (NTRS)
Giblin, T. W.; vanParadijs, J.; Kouveliotou, C.; Connaughton, V.; Wijers, R. A. M. J.; Briggs, M. S.; Preece, R. D.; Fishman, G. J.
In this Letter, we present the first evidence in the BATSE data for a prompt high-energy (25-300 keV) afterglow component from a gamma-ray burst, GRB 980923. The event consists of rapid variability lasting approximately 40 s followed by a smooth power-law emission tail lasting approximately 400 s. An abrupt change in spectral shape is found when the tail becomes noticeable. Our analysis reveals that the spectral evolution in the tail of the burst mimics that of a cooling synchrotron spectrum, similar to the spectral evolution of the low-energy afterglows for gamma-ray bursts. This evidence for a separate emission component is consistent with the internal-external shock scenario in the relativistic fireball picture. In particular, it illustrates that the external shocks can be generated during the gamma-ray emission phase, as in the case of GRB 990123.
Thermoelectric Performance Enhancement of Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) Composite Films by Addition of Dimethyl Sulfoxide and Urea
NASA Astrophysics Data System (ADS)
Kong, Fangfang; Liu, Congcong; Xu, Jingkun; Huang, Yao; Wang, Jianmin; Sun, Zhi
Significant enhancement of thermoelectric (TE) performance was observed for free-standing poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT: PSS) composite films obtained from a PEDOT:PSS aqueous solution by simultaneous addition of dimethyl sulfoxide (DMSO) and different concentrations of urea. The electrical conductivity was enhanced from 8.16 S cm-1 to over 400 S cm-1, and the maximum Seebeck coefficient reached a value of 18.81 μV K-1 at room temperature. The power factor of the PEDOT:PSS composite films reached 8.81 μW m-1 K-2. The highest thermoelectric figure of merit ( ZT) in this study was 0.024 at room temperature, which is at least one order of magnitude higher than most polymers and bulk Si. These results indicate that the obtained composite films are a promising thermoelectric material for applications in thermoelectric refrigeration and thermoelectric microgeneration.
Dynamic recrystallization in friction surfaced austenitic stainless steel coatings
Puli, Ramesh Janaki Ram, G.D.
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.
Towards 20 A negative hydrogen ion beams for up to 1 h: Achievements of the ELISE test facility (invited)
Fantz, U. Heinemann, B.; Wünderlich, D.; Riedl, R.; Kraus, W.; Nocentini, R.; Bonomo, F.
The large-scale RF-driven ion source of the test facility extraction from a large ion source experiment is aimed to deliver an accelerated ion current of 20 A D{sup −} (23 A H{sup −}) with an extracted electron-to-ion ratio below one for up to 1 h. Since the first plasma pulses for 20 s in volume operation in early 2013, followed by caesiation of the ion source, substantial progress has been achieved in extending the pulse length and the RF power. The record pulses in hydrogen are stable 400 s pulses with an extracted ion current of 18.3 A at 180 kW total RF power and 9.3 A at 80 kW stable for 1 h. For deuterium pulse, length and RF power are limited by the amount of co-extracted electrons.
Catalytic igniters and their use to ignite lean hydrogen-air mixtures
McLean, William J.; Thorne, Lawrence R.; Volponi, Joanne V.
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.
The N400 as a correlate of interpretively relevant linguistic rules: evidence from Hindi.
Choudhary, Kamal Kumar; Schlesewsky, Matthias; Roehm, Dietmar; Bornkessel-Schlesewsky, Ina
Classical views on the electrophysiology of language assume that different event-related potential (ERP) components index distinct linguistic subdomains. Hence, left-anterior negativities are often viewed as correlates of rule-based linguistic knowledge, whereas centro-parietal negativities (N400s) are taken to reflect (non-rule-based) semantic memory or aspects of lexical-semantic predictability. The present ERP study of case marking in Hindi challenges this clear-cut dichotomy. Though determined by a grammatical rule, the choice of subject case in Hindi is also interpretively relevant as it constrains the range of possible interpretations of the subject. For incorrect subject cases, we observed an N400, which was followed by a late positivity under certain circumstances. This finding suggests that violations of rule-based knowledge may engender an N400 when the rule is interpretively relevant.
Effects of event knowledge in processing verbal arguments
Bicknell, Klinton; Elman, Jeffrey L.; Hare, Mary; McRae, Ken; Kutas, Marta
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
Inhibition of stress induced hyperglucagonemia by administration of glucose in normal and alloxan-diabetic rat.
Klimes, I; Jurcovicová, J; Németh, S; Jezová, D; Vigas, M
The increase in plasma pancreatic glucagon which is known to occur under several stress conditions was confirmed in fed and 18 h prefasted rats subjected to a low, "stress producing" dose of the Noble-collip drum procedure (400 revolutions per 400 s). A single dose of exogenous glucose ( 1 g kg-1) injected 3 min and 20 s before stress into the jugular vein of intact fasted or fed animals anesthetized with pentobarbital 930 mg kg-1) completely abolished their hyperglucagonemic response in stress. In alloxan-diabetic hyperglycemic rats the stress-hyperglucagonemia was exaggerated, but was also suppressible by exogenous glucose. It was concluded that: 1. the stress induced hyperglucagonemic response of both intact and alloxan-diabetic rats was completely suppressible by administration of i.v. bolus of exogenous glucose; 2. the site inhibiting effect of glucose might be located either at the level of A cell or at the level of "'glucoreceptors" in hypothalamus.
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.
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.
[Using UV-Vis Absorbance for Characterization of Maturity in Composting Process with Different Materials].
Zhao, Yue; Wei, Yu-quan; Li, Yang; Xi, Bei-dou; Wei, Zi-min; Wang, Xing-lei; Zhao, Zhi-nan; Ding, Jei
The present study was conducted to assess the degree of humification in DOM during composting using different raw materials, and their effect on maturity of compost based on UV-Vis spectra measurements and chemometrics method. The raw materials of composting studied included chicken manure, pig manure, kitchen waste, lawn waste, fruits and vegetables waste, straw waste, green waste, sludge, and municipal solid waste. During composting, the parameters of UV-Vis spectra of DOM, including SUVA254 , SUVA280 , E250/E365, E4/E6, E2/E4, E2/E6, E253/E203, E253/E220, A226-400, S275-295 and S350-400 were calculated, Statistical analysis indicated that all the parameter were significantly changed during composting. SUVA254 and SUVA280 of DOM were continuously increased, E250/E365 and E4/E6 were continuously decreased in DOM, while A226-400, S275-295 and S350-400 of DOM at the final stage were significantly different with those at other stages of composting. Correlation analysis indicated that the parameters were significantly correlated with each other except for E2/E4 and E235/E203. Furthermore, principal component analysis suggested that A226-400, SUVA254, S350-400, SUVA280 and S275~295 were reasonable parameters for assessing the compost maturity. To distinguish maturity degree among different composts, hierarchical cluster analysis, an integrated tool utilizing multiple UV-Vis parameters, was performed based on the data (A226-400, SUVA254, S350-400, SUVA280 and S275-295) of DOM derived from the final stage of composting. Composts from different sources were clustered into 2 groups. The first group included chicken manure, pig manure, lawn waste, fruits and vegetables waste, green waste, sludge, and municipal solid waste characterized by a lower maturity degree, and the second group contained straw waste and kitchen waste associated with a higher maturity degree. The above results suggest that a multi-index of UV-Vis spectra could accurately evaluate the compost maturity
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).
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
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.
Material Assessment for ITER's Collective Thomson Scattering first mirror
Santos, R.; Policarpo, H.; Goncalves, B.; Varela, P.; Nonboel, E.; Klinkby, E.; Lauritzen, B.; Romanets, Y.; Luis, R.; Vaz, P.
The International Thermonuclear Energy Reactor (ITER) Collective Thomson Scattering (CTS) system is a diagnostic instrument that measures plasma density and velocity through Thomson scattering of microwave radiation. Some of the key components of the CTS are quasi-optical mirrors that are used to produce astigmatic beam patterns, which have impact on the strength and spatial resolution of the diagnostic signal. The mirrors are exposed to neutron radiation, which may alter the quality of the signal received. In this work, three different materials (molybdenum (Mo), stainless steel 316 (SS-316) and tungsten (W)) are considered for the first mirror of the CTS. The objective is to access which of the material studied are best suited for this mirror, considering different neutron radiation loads simulated scenarios defined by ITER, based on the resultant stresses and temperature distributions. For it, the neutron irradiation, and subsequent heat-load on the mirrors are simulated using the Monte Carlo N-Particle (MCNP) code. Based on the MCNP heat-load results, transient thermal-structural Finite Element Analysis (FEA) of the mirror over a 400 s discharge, with and without cooling on the rear side, are conducted using in commercial FEA software ANSYS. Results show that of the tested materials Mo and W are the most suitable material for this application. Even though, this study does not yet consider the variation of the material properties with temperature, it presents a quick initial satisfactory assessment that may be considered in subsequent and more complex analysis. (authors)
Language effects in second-language learners: A longitudinal electrophysiological study of spanish classroom learning.
Soskey, Laura; Holcomb, Phillip J; Midgley, Katherine J
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.
Evaluation of polymerization shrinkage of dental composites by an optical method.
Weig, K M; Magalhães Filho, T R; Costa Neto, C A; Costa, M F
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.
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
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.
Time frequency analysis of laser Doppler flowmetry signals recorded in response to a progressive pressure applied locally on anaesthetized healthy rats
NASA Astrophysics Data System (ADS)
Humeau, Anne; Koïtka, Audrey; Abraham, Pierre; Saumet, Jean-Louis; L'Huillier, Jean-Pierre
The laser Doppler flowmetry technique has recently been used to report a significant transient increase of the cutaneous blood flow signal, in response to a local non-noxious pressure applied progressively on the skin of both healthy humans and rats. This phenomenon is not entirely understood yet. In the present work, a time-frequency analysis is applied to signals recorded on anaesthetized healthy rats, at rest and during a cutaneous pressure-induced vasodilation (PIV). The comparison, at rest and during PIV, of the scalogram relative energies and scalogram relative amplitudes in five bands, corresponding to five characteristic frequencies, shows an increased contribution for the endothelial related metabolic activity in PIV signals, till 400 s after the beginning of the progressive pressure application. The other subsystems (heart, respiration, myogenic and neurogenic activities) contribute relatively less during PIV than at rest. The differences are statistically significant for all the relative activities in the interval 0-200 s following the beginning of the pressure. These results and others obtained on patients, such as diabetics, could increase the understanding of some cutaneous pathologies involved in various neurological diseases and in the pathophysiology of decubitus ulcers.
NASA PS400: A New Temperature Solid Lubricant Coating for High Temperature Wear Applications
NASA Technical Reports Server (NTRS)
DellaCorte, C.; Edmonds, B. J.
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.
Hemispheric differences in orthographic and semantic processing as revealed by event-related potentials
Dickson, Danielle S.; Federmeier, Kara D.
Differences in how the right and left hemispheres (RH, LH) apprehend visual words were examined using event-related potentials (ERPs) in a repetition paradigm with visual half-field (VF) presentation. In both hemispheres (RH/LVF, LH/RVF), initial presentation of items elicited similar and typical effects of orthographic neighborhood size, with larger N400s for orthographically regular items (words and pseudowords) than for irregular items (acronyms and meaningless illegal strings). However, hemispheric differences emerged on repetition effects. When items were repeated in the LH/RVF, orthographically regular items, relative to irregular items, elicited larger repetition effects on both the N250, a component reflecting processing at the level of visual form (orthography), and on the N400, which has been linked to semantic access. In contrast, in the RH/LVF, repetition effects were biased toward irregular items on the N250 and were similar in size across item types for the N400. The results suggest that processing in the LH is more strongly affected by wordform regularity than in the RH, either due to enhanced processing of familiar orthographic patterns or due to the fact that regular forms can be more readily mapped onto phonology. PMID:25278134
Acquiring concepts and features of novel words by two types of learning: direct mapping and inference.
Chen, Shuang; Wang, Lin; Yang, Yufang
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.
An improved Peronnet-Thibault mathematical model of human running performance.
Alvarez-Ramirez, Jose
Using an improved Peronnet-Thibault model to analyse the maximal power available during exercise, it was found that a 3rd-order relaxation process for the decreasing dynamics of aerobic power can describe accurately the data available for world track records and aerobic-to-total energy ratio (ATER). It was estimated that the time-scales for the decreasing dynamics are around 25 s for anaerobic power output and that they range from 2.12 h to 7.8 days for aerobic power output. In agreement with experimental evidence, the ATER showed a rapid increase during the first 300 s of exercise duration, to achieve an asymptote close to 100% after 1,000 s. In addition, the transition time when the ATER rose above 50% was found to be at a race duration of about 100 s, which would correspond to race distances of about 800 m. The results suggest that the aerobic power output achieves its maximal value at 300-400 s, and reaches a plateau at 26-28 W.kg(-1) that lasts about 5,000 s. After this period, the aerobic power output decreases slowly due to the contribution of long time-scale metabolic processes having smaller energy contributions (about 30% to 40% of the total aerobic power output).
Native-like brain processing of syntax can be attained by university foreign language learners.
Bowden, Harriet Wood; Steinhauer, Karsten; Sanz, Cristina; Ullman, Michael T
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.
Direct assessment of substrate binding to the Neurotransmitter:Sodium Symporter LeuT by solid state NMR
Erlendsson, Simon; Gotfryd, Kamil; Larsen, Flemming Hofmann; Mortensen, Jonas Sigurd; Geiger, Michel-Andreas; van Rossum, Barth-Jan; Oschkinat, Hartmut; Gether, Ulrik; Teilum, Kaare; Loland, Claus J
The Neurotransmitter:Sodium Symporters (NSSs) represent an important class of proteins mediating sodium-dependent uptake of neurotransmitters from the extracellular space. The substrate binding stoichiometry of the bacterial NSS protein, LeuT, and thus the principal transport mechanism, has been heavily debated. Here we used solid state NMR to specifically characterize the bound leucine ligand and probe the number of binding sites in LeuT. We were able to produce high-quality NMR spectra of substrate bound to microcrystalline LeuT samples and identify one set of sodium-dependent substrate-specific chemical shifts. Furthermore, our data show that the binding site mutants F253A and L400S, which probe the major S1 binding site and the proposed S2 binding site, respectively, retain sodium-dependent substrate binding in the S1 site similar to the wild-type protein. We conclude that under our experimental conditions there is only one detectable leucine molecule bound to LeuT. DOI: http://dx.doi.org/10.7554/eLife.19314.001 PMID:28117663
Continuous evolution of cloud droplet spectrum in cumulus cloud
NASA Astrophysics Data System (ADS)
Gotoh, Toshiyuki; Saito, Izumi; Watanabe, Takeshi
We have developed a new method that can seamlessly simulate the continuous growth of cloud droplets to rain drops from the first principle. A cubic box ascending with a mean updraft was introduced and the updraft velocity was self-consistently determined in such a way that the mean turbulent velocity within the box vanished. All the degrees of freedom were numerically integrated by using the Lagrangian dynamics for the droplets and the Eulerian direct numerical simulation for the turbulence. The key processes included were turbulent transport, condensation/evaporation, Reynolds number dependent drag, collision-coalescence, and entrainment. We have examined the evolution of the droplet spectrum over 400 s for a few of the initial droplet spectra: (1) single peak, (2) double peaks, (3) observed distribution, each of which had the same initial mean radius 10 μm and the same mean droplet density np = 125 cm-3. The turbulence was in steady state at Rλ = 86 and ɛ = 33 cm2s-3. It is found that the mass spectrum peak moves slowly toward the larger radius in the early stage and then quickly evolves to have the second peak through the autoconversion to the accretion state. Effects of the condensation and coalescence would also be reported. Grants-in-Aid for Scientific Research Nos.15H02218 and hp150088, hp160085 and jh160012.
Event related potentials and EEG components in a semantic memory search task.
Mecklinger, A; Kramer, A F; Strayer, D L
This study examined the effects of memory search and related processes on both time and frequency domain components of electroencephalographic activity. More specifically, we were interested in the relationship between EEG and event-related potential (ERP) components as a function of memory load and response type. Subjects performed a semantic memory search task in which they matched word probes to category labels. Consistent with previous studies, reaction time increased and accuracy decreased with increasing memory loads. A negative component of the ERP (N400) was found to reflect semantic mismatch: N400s were larger for the nontargets than for the targets. Two ERP components were found to be reciprocally related to memory load. P300 decreased and Negative Slow Wave increased in amplitude with increases in the size of the memory set. These two ERP components were reflected by different components in a Principal Components Analysis. The power in the theta band (5-7 Hz) also increased as a function of memory load and appears to be functionally and topographically related to the Negative Slow Wave in the ERP. It is argued that both measures are jointly determined and reflect the difficulty of the conceptual operations during memory search.
Developing an electrochemical deoxyribonucleic acid (DNA) biosensor on the basis of human interleukine-2 gene using an electroactive label.
Pournaghi-Azar, M H; Hejazi, M S; Alipour, E
Development of an electrochemical DNA biosensor based on a human interleukine-2 (IL-2) gene probe, using a pencil graphite electrode (PGE) as transducer and methylene blue (MB) as electroactive label is described. The sensor relies on the immobilization of a 20-mer single stranded oligonucleotide probe (hIL-2) related to the IL-2 gene on the electrode. The hybridization between the probe and its complementary sequence (chIL-2) as the target was studied by square wave voltammetry (SWV) of MB accumulated on the PGE. In this approach the extent of hybridization is evaluated on the basis of the difference between SWV signals of MB accumulated on the probe-PGE and MB accumulated on the probe-target-PGE. Some hybridization experiments with non-complementary oligonucleotides were carried out to assess whether the suggested DNA sensor responds selectively to the target. Some experimental variables affecting the performance of the biosensor including: polishing of PGE, its electrochemical activation conditions (i.e., activation potential and activation time) and probe immobilization conditions on the electrodes (i.e., immobilization potential and time) were investigated and the optimum values of 1.80 V and 300 s for PGE activation, and -0.5 V and 400s for the probe immobilization on the electrode were suggested.
Constitutive modelling of a tungsten heavy metal alloy
NASA Astrophysics Data System (ADS)
Skoglund, P.
The dynamic mechanical behaviour of a tungsten heavy metal alloy (WHA) with potential use as a kinetic energy penetrator is investigated. Mechanical properties related to tensile loading are measured at strain rates up to 400 s^{-1} and at temperatures from 20 ^{circ}C to about 500 ^{circ}C. From the experimental data parameters for the constitutive equations developed by Johnson and Cook (J&C) as well as Zerilli and Armstrong (Z&A) are determined. From the extracted models isothermal and adiabatic flow stress curves are calculated and compared to experiments. At high strain rates or high temperatures the J&C model deviates about 5-10% from experimental results, while the Z&A model shows a better agreement with the collected data. It should be emphasised that the Z&A model used in this work is developed for materials with body centred crystals whereas the WHA is a composite with both face centredand body centred crystals.
Variations in the corneal surface temperature with contact lens wear.
Ooi, E H; Ng, E Y K; Purslow, C; Acharya, R
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.
Evidence for an Early High-Energy Afterglow Observed with BATSE from GRB980923
NASA Technical Reports Server (NTRS)
Giblin, Tim; vanParadijs, Jan; Kouveliotou, Chryssa; Connaughton, Valerie; Wijers, Ralph A. M. J.; Fishman, Gerald
In this letter, we present for the first time evidence in the BATSE data for a prompt high-energy (25-300 keV) afterglow component from a Gamma-Ray Burst (GRB), GRB980923. The event ranks third highest in fluence (>25 keV) in the BATSE catalog and consists of a period of rapid variability lasting about 40 s followed by a smooth power law emission tail lasting about 400 s beyond the trigger time. An abrupt change in spectral shape is found when the tail becomes noticeable. Our analysis reveals that the spectral evolution in the tail of the burst mimics that of a cooling synchrotron spectrum, similar to the spectral evolution of the low-energy afterglows for GRBS. This evidence for a separate emission component is consistent with the internal-external shock scenario in the relativistic fireball picture. In particular, it illustrates that the external shocks can be generated during the primary gamma-ray emission phase, as in the case of GRB990123.
Stuttering and Natural Speech Processing of Semantic and Syntactic Constraints on Verbs
Weber-Fox, Christine; Hampton, Amanda
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
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
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.
ERP evidence for conceptual mappings and comparison processes during the comprehension of conventional and novel metaphors.
Lai, Vicky Tzuyin; Curran, Tim
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.
Odor-induced mood state modulates language comprehension by affecting processing strategies
Wang, Lin; Zhou, Bin; Zhou, Wen; Yang, Yufang
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
NASA Astrophysics Data System (ADS)
Ongena, J.; Koch, R.; Wolf, R.; Zohm, H.
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.
X-Ray Analysis of a Pulsating Source in the 3XMM Catalogue with a Period of 6.8 Minutes
NASA Astrophysics Data System (ADS)
Qiu, Hao; Zhou, Ping; Yu, Wenfei; Li, Xiangdong; Xu, Xiaojie
The 3XMM Serendipitous Source Catalogue (3XMM-SSC) contains over 500 thousand source detections from the XMM-Newton EPIC instruments. Along with a database search of the catalogue for unidentified objects of interest, we carry out a detailed study on one pulsating source, which was previously suggested to be a slow pulsar with an approximate period of 400s. We refine the period of the source to 407.88575(1) seconds based on the phase-connection analysis from the XMM-Newton and Swift observations spanning across nine years. The source shows stable X-ray properties (temperature and flux) during the observation epochs, the X-ray spectra is best described by a 2 keV blackbody emission plus 2 faint Fe lines at 6.4 keV and 6.7 keV, respectively. We also search for a possible counterpart in multi-wavebands. The low-mass counterpart candidate, together with the X-ray properties, suggests that the source is probably a low-mass X-ray binary at a distance around 1.5 kpc.
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
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.
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.
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.
Intermittent heat instabilities in an air plume
NASA Astrophysics Data System (ADS)
Le Mouël, Jean-Louis; Kossobokov, Vladimir G.; Perrier, Frederic; Morat, Pierre
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.
Immobilization of chromate in hyperalkaline waste streams by green rusts and zero-valent iron.
Rogers, Christine M; Burke, Ian T; Ahmed, Imad A M; Shaw, Samuel
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.
Optimizing the Face Paradigm of BCI System by Modified Mismatch Negative Paradigm
Zhou, Sijie; Jin, Jing; Daly, Ian; Wang, Xingyu; Cichocki, Andrzej
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
Effect of Sophora flavescens on non-specific immune response of tilapia (GIFT Oreochromis niloticus) and disease resistance against Streptococcus agalactiae.
Wu, Ying-rui; Gong, Qing-fang; Fang, Hong; Liang, Wan-wen; Chen, Ming; He, Rui-jie
The paper describes the effect of a diet supplemented with the Chinese traditional herbal medicine Sophora flavescens on the immunity and disease resistance of an Oreochromis niloticus GIFT strain. Experimental diets containing 0.025%, 0.050%, 0.100%, 0.200%, and 0.400% S. flavescens, as well as a control group without S. flavescens were used. We tested the non-specific humoral immune responses (lysozyme, antiprotease, and complement) and cellular immune responses (reactive oxygen species and nitrogen species production and myeloperoxidase), as well as disease resistance against Streptococcus agalactiae. S. flavescens supplementation at all dose significantly enhanced serum lysozyme, antiprotease, and natural hemolytic complement activity. Similarly, all S. flavescens doses enhanced cellular myeloperoxidase activity. The increased production of reactive oxygen species and reactive nitrogen intermediates by peripheral blood leucocytes was observed in most of the treatment groups throughout the test period. The fish fed 0.100% S. flavescens had a percent mortality of 21.1% and a relative percent survival of 73.3% compared with the group fed the basal diet during the S. agalactiae challenge. The results suggest that S. flavescens can be recommended as a tilapia feed supplement to enhance fish immunity and disease resistance against S. agalactiae.
Shear Assisted Electrochemical Exfoliation of Graphite to Graphene.
Shinde, Dhanraj B; Brenker, Jason; Easton, Christopher D; Tabor, Rico F; Neild, Adrian; Majumder, Mainak
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.
Large-sized polysomes in Chironomus tentans salivary glands and their relation to Balbiani ring 75S RNA
Polysomes from the salivary glands of Chironomus tentans were investigated to determine whether Balbiani ring 75S RNA is incorporated into polysomal structures, and thus probably acts as messenger RNA. A new extraction technique for obtaining ribonucleoproteins was applied that gives a high yield of polysomes with only moderate degradation of the cytoplasmic, high molecular weight RNA. The polysomes sedimented in a broad region (200-2,000S) with a peak value of about 700S, which suggested that they were partly of very large sizes. This was confirmed by visualization of the polysomes in the electron microscope: 400S polysomes contained mainly 11-16 ribosomes, and 1,500S polysomes about 60 ribosomes per polysome. However, polysomes containing 100 or more ribosomes were also observed. It was further established that most of the cytoplasmic 75S RNA was located in polysomes, preferentially in the most rapidly sedimenting ones. From the available information on Balbiani ring RNA in cytoplasm and the present demonstration of 75S RNA molecules in polysomes, it was concluded that at least some Balbiani ring RNA, generated as 75S RNA within the Balbiani rings, eventually enters polysomes without being measurably changed in size. The present information on the potential amino acid coding sequences in 75S RNA is discussed in relation to the large size of the polysomes observed. PMID:856829
Optimization of a polymer top electrode for inverted semitransparent organic solar cells
Zhou, Yinhua; Cheun, Hyeunseok; Choi, Seungkeun; Fuentes-Hernandez, Canek; Kippelen, Bernard
We report on semitransparent organic solar cells using a single-layer blend based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the top electrode. The PEDOT:PSS blend was prepared by mixing a high-conductivity formulation of PEDOT:PSS (H.C. Starck CLEVIOS PH-1000) and another formulation of PEDOT:PSS (H.C. Starck CLEVIOS CPP 105D). The PEDOT:PSS blend yields good wetting properties on the hydrophobic surface of a blend of poly(3-hexylthiophene) (P3HT) with phenyl-C61-butyric acid methyl ester (PC60 BM), and shows a conductivity over 400 S cm-1. Semitransparent organic solar cells using the PEDOT:PSS blend as the top electrode with a structure of glass/ITO/ZnO/P3HT:PC60BM/PEDOT:PSS-blend exhibited an average power conversion efficiency of 2.4% estimated for 100 mW cm-2 AM 1.5G illumination.
Different mechanisms for role relations versus verb-action congruence effects: evidence from ERPs in picture-sentence verification.
Knoeferle, Pia; Urbach, Thomas P; Kutas, Marta
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.
Effects of muscle contraction on the load-strain properties of frog aponeurosis and tendon.
Lieber, R L; Leonard, M E; Brown-Maupin, C G
The mechanical properties of the frog semitendinosus (ST) tendon and aponeurosis were measured during passive tensile loading to a force equal to ST maximum tetanic tension and during active isometric muscle contraction. During active contraction, both the tendon and aponeurosis regions initially strained at rates exceeding 400%/s while near the end of the muscle contraction, strain rates were nearly zero. At this point, the strain in the tendon region was equal to that observed during slow passive loading to the same tension level. However, for the aponeurosis, even near the zero strain rate, strain at the end of the active contraction was significantly below that observed during slow passive loading (p < 0. 001). Specifically, when aponeurosis strain rate was almost zero, aponeurosis strain was 13.8 +/- 3% (means +/- SEM, n = 10), which was significantly below that measured during passive loading (23.7 +/- 5%) suggesting that active contraction actually altered aponeurosis material properties. These data demonstrate that, while the tendon and aponeurosis regions have different passive biomechanical properties and both demonstrate viscosity typical of other connective tissues, the aponeurosis region of the frog ST actually changed its intrinsic properties during muscle contraction. Thus, extrapolation of biomechanical data obtained at nonphysiological strain rates or under conditions where the muscle-tendon junction has been interrupted should be made with caution.
Filling the gap of existing MWA-VCS archival data
NASA Astrophysics Data System (ADS)
Xue, M.; Bhat, R.; Tremblay, S.; Ord, S.; Sobey, C.; Kirsten, F.
Since July 2014, around 110 hours of high time resolution voltage data observed by MWA Voltage Capture System (VCS; Tremblay et al. 2015) have been archived on tapes in the Pawsey Supercomputing Centre. Except some short duration test data and calibration data, the total amount of the observation data which have a duration longer than 400 s is 84 hours. These data cover a significant portion of a lot of the Southern sky and could be used for many science purposes including radio pulsars census and fast radio bursts (FRBs) searching. But there are still some 'holes' in the sky that we do not have VCS archival data for yet. We are proposing a set of MWA-VCS drift scan observations of 3 hours to fill some of these 'holes' and help provide a more complete MWA-VCS data set. We will also census known (cataloged) pulsars in these areas. These observations would be performed between 170-200 MHz. This project will form part of the PhD program of Mengyao Xue.
An Evolutionary S-wave Model of the Earth Upper Mantle and Transition Zone
NASA Astrophysics Data System (ADS)
Debayle, E.; Dubuffet, F.; Durand, S.
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.
Direct assessment of substrate binding to the Neurotransmitter:Sodium Symporter LeuT by solid state NMR.
Erlendsson, Simon; Gotfryd, Kamil; Larsen, Flemming Hofmann; Mortensen, Jonas Sigurd; Geiger, Michel-Andreas; van Rossum, Barth-Jan; Oschkinat, Hartmut; Gether, Ulrik; Teilum, Kaare; Loland, Claus J
The Neurotransmitter:Sodium Symporters (NSSs) represent an important class of proteins mediating sodium-dependent uptake of neurotransmitters from the extracellular space. The substrate binding stoichiometry of the bacterial NSS protein, LeuT, and thus the principal transport mechanism, has been heavily debated. Here we used solid state NMR to specifically characterize the bound leucine ligand and probe the number of binding sites in LeuT. We were able to produce high-quality NMR spectra of substrate bound to microcrystalline LeuT samples and identify one set of sodium-dependent substrate-specific chemical shifts. Furthermore, our data show that the binding site mutants F253A and L400S, which probe the major S1 binding site and the proposed S2 binding site, respectively, retain sodium-dependent substrate binding in the S1 site similar to the wild-type protein. We conclude that under our experimental conditions there is only one detectable leucine molecule bound to LeuT.
Moisture-related Weakening and Strengthening of Faults for Quartz-poor Gabbro and Quartz-rich Granite
NASA Astrophysics Data System (ADS)
Mizoguchi, K.; Hirose, T.; Shimamoto, T.; Fukuyama, E.
Significance of moisture-related mechanisms has been pointed out from the slide-hold-slide tests on gabbro (quartz-poor rock) under dry and room-humid conditions using high-speed rotary-shear apparatus [Mizoguchi et al., 2006, GRL]. In this paper, we conducted similar experiments using granite (quartz-rich rock) and discuss the results from the viewpoints of the quartz content. In the experiments, one of the two solid-cylindrical specimens (diameter ~ 25 mm) was rotated with a speed of 100 rpm (equivalent slip velocity is ~ 85 mm/s) under a constant normal stress of 0.62MPa. We conducted the tests using initially bare rock sample (1) and rock sample initially containing wear materials produced during sliding (2). A typical result for the gabbro case (1) is that friction coefficient decreased from more than 1.0 (we call initial friction) to less than 0.4 when the amount of slip was between 10 and 30 m then it became a steady state. The layer of wear materials along the fault was about 50 μm thick at steady state. Since the fault was not covered with a jacket, wear materials were squeezed out from the fault during sliding. The result for the gabbro case (2) showed a similar slip-weakening curve to that of the gabbro case (1), it represented a remarkable dependence of the initial friction on hold time and humidity. Under a room-humidity condition, the initial friction increased from 0.2 to 1.2 as hold time increased as 200 ~ 400 s. In contrast, under the dry condition, the initial friction did not increase with hold time and kept the level of 0.2. To explain this time- and humidity- dependent frictional behavior of gabbro, a mechanism of moisture-drained weakening due to frictional heating and moisture-absorbed strengthening due to cooling is proposed. The result for the granite case (1) showed that the friction decreased from more than 0.9 down to less than 0.2 when the slip was between 50 and 75 m. The dynamic slip weakening behavior is similar to that of gabbro
The reliability of the N400 in single subjects: Implications for patients with disorders of consciousness
Cruse, Damian; Beukema, Steve; Chennu, Srivas; Malins, Jeffrey G.; Owen, Adrian M.; McRae, Ken
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
Quantification, prediction, and the online impact of sentence truth-value: Evidence from event-related potentials.
Nieuwland, Mante S
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.
The Truth Before and After: Brain Potentials Reveal Automatic Activation of Event Knowledge during Sentence Comprehension.
Nieuwland, Mante S
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.
Neural Mechanisms of Object Naming and Word Comprehension in Primary Progressive Aphasia
Hurley, Robert S.; Paller, Ken A.; Rogalksi, Emily J.; Mesulam, M. Marsel
Primary progressive aphasia is a neurodegenerative syndrome that causes a gradual atrophy of the left hemisphere language network, leading to impairments of object naming (anomia) and word comprehension. In 33 human subjects with PPA, object naming and word comprehension were explored with N400 potentials elicited by picture-word or picture-picture matching tasks. Two mechanisms of impairment were identified. In one group of patients, where the object name could be recognized but not retrieved during verbal naming, N400s in picture-word trials were also abnormal, revealing an associative basis for retrieval anomia. In these patients, a putative pre-phonological signal (i.e. lemma) evoked by the object picture appears to have become too weak to elicit retrieval, but not necessarily too weak to support the informationally less taxing process of recognition. A second group of PPA patients showed more severe naming deficits - the object name was neither verbalized nor recognized. Furthermore, nouns of the same category (but not those of other object categories) could not be identified as mismatches. This blurring of intra- but not inter-category differentiation of word meaning was correlated with anterior temporal atrophy, predominantly in the left hemisphere, especially along the superior temporal gyrus. Although not part of the classic language network, this area appears critical for proceeding from generic to specific levels of word comprehension and object naming. N400 abnormalities emerged for lexical (picture-word) but not non-verbal (picture-picture) associations, supporting a dual-route rather than amodal organization of object concepts. PMID:22492040
DNA ionogel: Structure and self-assembly.
Pandey, Pankaj Kumar; Rawat, Kamla; Aswal, V K; Kohlbrecher, J; Bohidar, H B
DNA dissolved in ionic liquid (IL) solution (1-ethyl-3-methylimidazolium chloride, [C2mim][Cl]) showed a transition to the gel phase ([DNA] ≥ 1% (w/v)). The gelation time was 400 s for the 1% [IL] sample which reduced to 260 s for 5% [IL] concentration. Gelation times, obtained from the viscosity and ergodicity breaking from the dynamic structure factor data, were remarkably identical to each other. Correspondingly, the gelation temperature which was ∼60 °C increased to 67 °C with [IL] content. The small angle neutron scattering (SANS) structure factor profile revealed the presence of the following three distinct length scales: (a) mesh size, ξ ≈ 3 ± 0.5 nm for ionogels, and ≈0.73 ± 0.06 nm, for sol; (b) cross-sectional radius of DNA strand, Rc ≈ 1.6 ± 0.1 nm; and (c) the characteristic inter-cluster distance ≈33 ± 5 nm. Physical conformation of the DNA-IL complexes remained close to the Gaussian coil definition. It was observed that without IL, in the sol phase, the system was completely ergodic and did not gel, while on addition of IL a sudden transition to the non-ergodic (arrested) gel phase occurred. This was due to the formation of an amorphous network of DNA-IL complexes preceding gelation. In summary, it is shown that the DNA ionogels can be prepared with a tunable gel strength (27-70 Pa) and gelation temperature (60-67 °C). Further, the relaxation dynamics was found to be hierarchical in IL content of the gel, revealing considerable self-organization.
Shen Yuandeng; Liu Yu
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.
Kuckein, C.; Collados, M.; Sainz, R. Manso
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.
Particle Detectors and Data Analysis for Cusp Transient Features Campaign
NASA Technical Reports Server (NTRS)
Sharber, James R.
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.
Particle Detectors and Data Analysis for Cusp Transient Features Campaign
NASA Technical Reports Server (NTRS)
Sharber, James R.
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.
Apparent Dependence of Rate- and State-Dependent Friction Parameters on Loading Velocity and Cumulative Displacement Inferred from Large-Scale Biaxial Friction Experiments
NASA Astrophysics Data System (ADS)
Urata, Yumi; Yamashita, Futoshi; Fukuyama, Eiichi; Noda, Hiroyuki; Mizoguchi, Kazuo
We investigated the constitutive parameters in the rate- and state-dependent friction (RSF) law by conducting numerical simulations, using the friction data from large-scale biaxial rock friction experiments for Indian metagabbro. The sliding surface area was 1.5 m long and 0.5 m wide, slid for 400 s under a normal stress of 1.33 MPa at a loading velocity of either 0.1 or 1.0 mm/s. During the experiments, many stick-slips were observed and those features were as follows. (1) The friction drop and recurrence time of the stick-slip events increased with cumulative slip displacement in an experiment before which the gouges on the surface were removed, but they became almost constant throughout an experiment conducted after several experiments without gouge removal. (2) The friction drop was larger and the recurrence time was shorter in the experiments with faster loading velocity. We applied a one-degree-of-freedom spring-slider model with mass to estimate the RSF parameters by fitting the stick-slip intervals and slip-weakening curves measured based on spring force and acceleration of the specimens. We developed an efficient algorithm for the numerical time integration, and we conducted forward modeling for evolution parameters (b) and the state-evolution distances (L_{c} ), keeping the direct effect parameter (a) constant. We then identified the confident range of b and L_{c} values. Comparison between the results of the experiments and our simulations suggests that both b and L_{c} increase as the cumulative slip displacement increases, and b increases and L_{c} decreases as the loading velocity increases. Conventional RSF laws could not explain the large-scale friction data, and more complex state evolution laws are needed.
Quantification, Prediction, and the Online Impact of Sentence Truth-Value: Evidence From Event-Related Potentials
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
Oscillatory Phenomena in a Solar Network Region
NASA Astrophysics Data System (ADS)
Tziotziou, K.; Tsiropoula, G.; Schwartz, P.; Heinzel, P.
Multi-wavelength, multi-instrument observations, obtained during a coordinated observing campaign on October 2005 by the ground-based Dutch Open Telescope (DOT), and by instruments on the spacecraft Solar and Heliospheric Observatory (SoHO) and Transition Region and Coronal Explorer (TRACE), are used to study oscillatory phenomena in a solar network region. Temporal variations of the intensities and velocities in a region of the quiet Sun containing several dark mottles and in a region with several bright points defining the network boundaries (NB) are investigated with the aim of finding similarities and/or differences in the oscillatory phenomena observed in these two regions and in different spectral lines formed from the chromosphere to the transition region, as well as propagation characteristics of waves. A wavelet, phase difference and coherence analyses were performed indicating a periodicity around 5 min in all considered lines for both regions. V-V phase differences in the NB region point to an upward propagation of, most probably, acoustic waves, while in the region of mottles they indicate a non vertical propagation of waves, due to the presence of several inclined mottles along the line-of-sight. In mottles, for periods of 250-400 s the phase difference is mainly negative suggesting that propagating waves encounter a boundary and are refracted and reflected. However, limitations arising from the complex topology of the magnetic field, the formation conditions and heights of the examined spectral lines and the low spatial resolution of the space instruments influence the exact interpretation of the phase differences.
Multiwavelength analysis of a solar quiet region
NASA Astrophysics Data System (ADS)
Tsiropoula, G.; Tziotziou, K.; Schwartz, P.; Heinzel, P.
Context: We examine oscillatory phenomena in a solar network region from multi-wavelength observations obtained by the ground-based Dutch Open Telescope (DOT) and by the Coronal Diagnostic Spectrometer (CDS) on the spacecraft Solar and Heliospheric Observatory (SoHO). The observations were obtained during a coordinated observing campaign in October 2005. Aims: We investigate the temporal variations of the intensities and the velocities in two distinct regions of the quiet Sun, one containing several dark mottles and the other several bright points defining the network boundaries (NB). The aim is to find similarities and/or differences in the oscillatory phenomena observed in these two regions and in different spectral lines formed from the chromosphere to the transition region, as well as the propagation characteristics of waves. Methods: Intensity and velocity variations are studied with wavelet and phase difference analyses. Results: Both regions (i.e. mottles and NB) show a periodicity of ~5 min in all considered lines. The V-V phase differences in the NB region point to an upward propagation of waves; in the region of mottles, for periods of 250-400 s, the phase difference is mainly negative, which suggests a downward propagation, in turn indicating a refraction of waves from the inclined magnetic field of mottles along the line-of-sight. Conclusions: The phase differences at the NB arise from a predominance of upward propagating waves. In the mottles' region, the negative phase differences we found suggest that propagating waves encounter a boundary and are refracted and reflected. Of course, several limitations exist in the exact interpretation of the phase differences, e.g. the complex topology of the magnetic field, the formation conditions and heights of the examined spectral lines, and the low spatial resolution.
Antibacterial activity and PK/PD of ceftriaxone against penicillin-resistant Streptococcus pneumoniae and beta-lactamase-negative ampicillin-resistant Haemophilus influenzae isolates from patients with community-acquired pneumonia.
Ohno, Akira; Ishii, Yoshikazu; Kobayashi, Intetsu; Yamaguchi, Keizo
The suitability of ceftriaxone for penicillin-resistant Streptococcus pneumoniae (PRSP) and ampicillin-resistant Haemophilus influenzae (especially beta-lactamase-negative ampicillin-resistant (BLNAR) H. influenzae) and the relationship between in vitro antimicrobial activities and pharmacokinetic parameters were evaluated. The values for percentage of time above the MIC (%T>MIC) for ceftriaxone, cefotiam, flomoxef, sulbactam/cefoperazone, sulbactam/ampicillin, and meropenem, using 400 S. pneumoniae isolates and 430 H. influenzae isolates from patients with community-acquired pneumonia (CAP) from more than 100 geographically diverse medical centers during January to July of 2005, were calculated by measuring the MIC for each isolate and by using patameters of pharmacokinetics. A broth microdilution method was used to determine the MIC, using the guidelines of the Clinical and Laboratory Standards Institute (CLSI). Meropenem showed the lowest MIC against penicillin-susceptible S. pneumoniae, followed by sulbactam/cefoperazone and ceftriaxone. Ceftriaxone had the best activity against penicillin-resistant S. pneumoniae and beta-lactamase-negative and beta-lactamase-producing ampicillin-resistant H. influenzae. Ceftriaxone was unique, showing a long elimination half-life and low MIC values where its serum level duration time was above the MIC for longer than other cephalosporins. Accordingly, the %T>MIC of ceftriaxone for a once-daily administration greatly exceeded the efficacy levels of those for the other antibacterial agents tested. Ceftriaxone has an excellent balance between in vitro antimicrobial activities and pharmacokinetic profiles; and therefore remains effective as a therapeutic agent against PRSP and BLNAR H. influenzae in CAP.
Association of abnormal semantic processing with delusion-like ideation in frequent cannabis users: an electrophysiological study
Christensen, Bruce K.; Streiner, David L.; Roy, Carolyn; Patriciu, Iulia; Zipursky, Robert B.
Rationale Frequent cannabis use is a risk marker for schizophrenia and delusions, but the neurocognitive mechanisms of this relationship remain unclear. Objectives We sought evidence that cannabis users have deficits in processing relationships between meaningful stimuli, similar to abnormalities reported in schizophrenia, and that these deficits are associated with delusion-like ideation. We used the N400 event-related brain potential (ERP) waveform as a neurophysiological probe of activation of concepts in semantic memory. We hypothesized that cannabis users would exhibit larger (more negative) than normal N400 amplitudes in response to stimuli meaningfully related to a preceding prime—reflecting deficient activation of concepts related to the prime. We further hypothesized that the magnitude of this abnormality would correlate with severity of delusion-like ideation. Methods We recorded ERPs in 24 frequent cannabis users and 24 non-using comparison participants who viewed prime words followed by targets which were either words related or unrelated to the prime or pronounceable non-words. The participants' task was to indicate whether the target was a word. Delusion-like ideation was measured via the Schizotypal Personality Questionnaire. Results Contrary to our hypothesis, cannabis users exhibited smaller than normal N400s to both related and unrelated targets. These abnormalities correlated with delusion-like ideation in cannabis users only. Conclusions The results are consistent with a generalized abnormality of activation within semantic memory neural networks in cannabis users. Further research is needed to investigate whether such an abnormality plays a role in the development of delusion-like ideation in cannabis users. PMID:22782461
Processing of soft Hispanic cheese ("queso fresco") using thermo-sonicated milk: a study of physicochemical characteristics and storage life.
Bermúdez-Aguirre, Daniela; Barbosa-Cánovas, Gustavo V
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.
Substrate-Triggered Addition of Dioxygen to the Diferrous Cofactor of Aldehyde-Deformylating Oxygenase to form a Diferric-Peroxide Intermediate†
Nørgaard, Hanne; Warui, Douglas M.; Rajakovich, Lauren J.; Chang, Wei-chen; Booker, Squire J.; Krebs, Carsten; Bollinger, J. Martin
Cyanobacterial aldehyde-deformylating oxygenases (ADOs) belong to the ferritin-like diiron-carboxylate superfamily of dioxygen-activating proteins. They catalyze conversion of saturated or mono-unsaturated Cn fatty aldehydes to formate and the corresponding Cn-1 alkanes or alkenes, respectively. This unusual, apparently redox-neutral transformation actually requires four electrons per turnover to reduce the O2 co-substrate to the oxidation state of water and incorporates one O-atom from O2 into the formate co-product. We show here that the complex of the diiron(II/II) form of ADO from Nostoc punctiforme (Np) with an aldehyde substrate reacts with O2 to form a colored intermediate with spectroscopic properties suggestive of a Fe2III/III complex with a bound peroxide. Its Mössbauer spectra reveal that the intermediate possesses an antiferromagnetically (AF) coupled Fe2III/III center with resolved sub-sites. The intermediate is long-lived in the absence of a reducing system, decaying slowly (t1/2 ~ 400 s at 5 °C) to produce a very modest yield of formate (< 0.15 enzyme equivalents), but reacts rapidly with the fully reduced form of 1-methoxy-5-methylphenazine (MeOPMS) to yield product, albeit at only ~ 50% of the maximum theoretical yield (owing to competition from one or more unproductive pathway). The results represent the most definitive evidence to date that ADO can use a diiron cofactor (rather than a homo- or hetero-dinuclear cluster involving another transition metal) and provide support for a mechanism involving attack on the carbonyl of the bound substrate by the reduced O2 moiety to form a Fe2III/III-peroxyhemiacetal complex, which undergoes reductive O-O-bond cleavage, leading to C1–C2 radical fragmentation and formation of the alk(a/e)ne and formate products. PMID:23987523
Erosion/redeposition analysis of the ITER first wall with convective and non-convective plasma transport
Brooks, J. N.; Allain, J. P.; Rognlien, T. D.
Sputtering erosion/redeposition is analyzed for IAEA [Report GA10FDR1-01-07-13 (2001)] plasma facing components, with scrape-off layer (SOL) plasma convective radial transport and nonconvective (diffusion-only) transport. The analysis uses the UEDGE code [T .D. Rognlien et al., J. Nucl. Mater. 196, 347 (1992)] and DEGAS code [D. P. Stotler et al., Contrib. Plasma Phys. 40, 221 (2000) ] to compute plasma SOL profiles and ion and neutral fluxes to the wall, TRIM-SP code [J. P. Biersack, W. Eckstein, J. Appl. Phys. A34, 73 (1984)] to compute sputter yields, and the REDEP/WBC code package [J. N. Brooks, Fusion Eng. Des. 60, 515 (2002)] for three-dimensional kinetic modeling of sputtered particle transport. Convective transport is modeled for the background plasma by a radially varying outward-flow component of the fluid velocity, and for the impurity ions by three models designed to bracket existing models/data. Results are reported here for the first wall with the reference beryllium coating and an alternative tungsten coating. The analysis shows: (1) sputtering erosion for convective flow is 20-40 times higher than for diffusion-only but acceptably low ({approx}0.3 nm/s) for beryllium, and very low ({approx}0.002 nm/s) for tungsten; (2) plasma contamination by wall sputtering, with convective flow, is of order 1% for beryllium and negligible for tungsten; (3) wall-to-divertor beryllium transport may be significant ({approx}10%-60% of the sputtered Be current); (4) tritium co-deposition in redeposited beryllium may be high ({approx}1-6 gT/400 s pulse)
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.
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.
Assessment of total efficiency in adiabatic engines
NASA Astrophysics Data System (ADS)
Mitianiec, W.
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.
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
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.
Microstructure of fat globules in whole milk after thermosonication treatment.
Bermúdez-Aguirre, D; Mawson, R; Barbosa-Cánovas, G V
The structure of fat globules in whole milk was studied after heat and thermosonication treatments to observe what happens during these processes at the microscopic level using scanning electron microscopy. Raw whole milk was thermosonicated in an ultrasonic processor-Hielscher UP400S (400 W, 24 kHz, 120 microm amplitude), using a 22-mm probe at 63 degrees C for 30 min. Heat treatment involved heating the milk at 63 degrees C for 30 min. Color and fat content were measured to correlate the images with analytical measurements. The results showed that the surface of the fat globule was completely roughened after thermosonication. Ultrasound waves were responsible for disintegrating the milk fat globule membrane (MFGM) by releasing the triacylglycerols. Furthermore, the overall structure of milk after sonication showed smaller fat globules (smaller than 1 microm) and a granular surface. This was due to the interaction between the disrupted MFGM and some casein micelles. Minor changes in the aspect of the globules between thermal and raw milks were detected. Color measurements showed higher L* values for sonicated samples. Sonicated milk was whiter (92.37 +/- 0.20) and generally showed a better degree of luminosity and homogenization compared to thermal treated milk (88.25 +/- 0.67) and raw milk (87.82 +/- 0.18). Fat content analysis yielded a higher value after sonication (4.24%) compared to untreated raw milk (4.04%) because fat extraction is more efficient after sonication. The advantages of thermosonicated milk are that it can be pasteurized and homogenized in just 1 step, it can be produced with important cost savings, and it has better characteristics, making thermosonication a potential processing method for milk and most other dairy products.
Fabrication and In vivo Thrombogenicity Testing of Nitric Oxide Generating Artificial Lungs
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
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
Microstructure Evolution and Abrasive Wear Behavior of Ti-6Al-4V Alloy
NASA Astrophysics Data System (ADS)
Hadke, Shreyash; Khatirkar, Rajesh K.; Shekhawat, Satish K.; Jain, Shreyans; Sapate, Sanjay G.
This paper investigates the effect of quenching and aging treatment on microstructure and abrasive wear of Ti-6Al-4V alloy. The as-received alloy was solution treated at 1339 K, then oil quenched, followed by aging at 823 K for 4 h (14,400 s). The microstructures of as-received and quench-aged specimens were characterized by using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, and electron backscattered diffraction techniques. The as-received specimen consisted of very fine α grains (average grain size 2 μm) with β phase uniformly dispersed throughout. The microstructure of the quench-aged specimen showed α plates (formed by the decomposition of α' during aging). The β phase precipitated out of α' martensite during aging and hence was dispersed uniformly in the α matrix. Ti-6Al-4V alloy was quench-aged to achieve maximum hardness with a view that the increased hardness would lead to an improvement in abrasive wear behavior. Two-body abrasive wear tests were carried out on the as-received and quench-aged specimens using pin-on-disk apparatus with SiC as abrasive media (150-grit size). The effect of sliding distance and normal load on the abrasive wear behavior was studied. The wear resistance of the as-received specimen was greater than that of quench-aged specimen, while hardness of the as-received specimen was lower than that of quench-aged specimen. The abrasive wear behavior of Ti-6Al-4V alloy has been explained based on morphology/microstructure of the alloy and the associated wear mechanism(s).
Fast "Feast/Famine" Cycles for Studying Microbial Physiology Under Dynamic Conditions: A Case Study with Saccharomyces cerevisiae
Suarez-Mendez, Camilo A.; Sousa, Andre; Heijnen, Joseph J.; Wahl, Aljoscha
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
Inter-pulse high-resolution gamma-ray spectra using a 14 MeV pulsed neutron generator
Evans, L.G.; Trombka, J.I.; Jensen, D.H.; Stephenson, W.A.; Hoover, R.A.; Mikesell, J.L.; Tanner, A.B.; Senftle, F.E.
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.
Fabrication and in vivo thrombogenicity testing of nitric oxide generating artificial lungs.
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
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 m(2) 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 h at an activated clotting time of 350-400 s. 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 h (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 h (132.8 ± 4.5 μg/dL) and unchanged in the controls. This study demonstrates that NO generating gas exchange fibers could be a potentially effective way to control coagulation inside artificial lungs.
Optimization of a nanomedicine-based silicon phthalocyanine 4 photodynamic therapy (Pc 4-PDT) strategy for targeted treatment of EGFR-overexpressing cancers.
Master, Alyssa M; Livingston, Megan; Oleinick, Nancy L; Sen Gupta, Anirban
The current clinical mainstays for cancer treatment, namely, surgical resection, chemotherapy, and radiotherapy, can cause significant trauma, systemic toxicity, and functional/cosmetic debilitation of tissue, especially if repetitive treatment becomes necessary due to tumor recurrence. Hence there is significant clinical interest in alternate treatment strategies like photodynamic therapy (PDT) which can effectively and selectively eradicate tumors and can be safely repeated if needed. We have previously demonstrated that the second-generation photosensitizer Pc 4 (silicon phthalocyanine 4) can be formulated within polymeric micelles, and these micelles can be specifically targeted to EGFR-overexpressing cancer cells using GE11 peptide ligands, to enhance cell-specific Pc 4 delivery and internalization. In the current study, we report on the in vitro optimization of the EGFR-targeting, Pc 4 loading of the micellar nanoformulation, along with optimization of the corresponding photoirradiation conditions to maximize Pc 4 delivery, internalization, and subsequent PDT-induced cytotoxicity in EGFR-overexpressing cells in vitro. In our studies, absorption and fluorescence spectroscopy were used to monitor the cell-specific uptake of the GE11-decorated Pc 4-loaded micelles and the cytotoxic singlet oxygen production from the micelle-encapsulated Pc 4, to determine the optimum ligand density and Pc 4 loading. It was found that the micelle formulations bearing 10 mol % of GE11-modified polymer component resulted in the highest cellular uptake in EGFR-overexpressing A431 cells within the shortest incubation periods. Also, the loading of ∼ 50 μg of Pc 4 per mg of polymer in these micellar formulations resulted in the highest levels of singlet oxygen production. When formulations bearing these optimized parameters were tested in vitro on A431 cells for PDT effect, a formulation dose containing 400 nM Pc 4 and photoirradiation duration of 400 s at a fluence of 200 mJ/cm(2
A novel rheo-optical device for studying complex fluids in a double shear plate geometry
NASA Astrophysics Data System (ADS)
Boitte, Jean-Baptiste; Vizcaïno, Claude; Benyahia, Lazhar; Herry, Jean-Marie; Michon, Camille; Hayert, Murielle
A new rheo-optical shearing device was designed to investigate the structural evolution of complex material under shear flow. Seeking to keep the area under study constantly within the field of vision, it was conceived to produce shear flow by relying on the uniaxial translation of two parallel plates. The device features three modes of translation motion: step strain (0.02-320), constant shear rate (0.01-400 s-1), and oscillation (0.01-20 Hz) flow. Because the temperature is controlled by using a Peltier module coupled with a water cooling system, temperatures can range from 10 to 80 °C. The sample is loaded onto a user-friendly plate on which standard glasses can be attached with a depression vacuum pump. The principle innovation of the proposed rheo-optical shearing device lies in the fact that this suction system renders the microscopy glasses one with the plates, thereby ensuring their perfect planarity and parallelism. The gap width between the two plates can range from 0 to 5 mm. The device was designed to fit on any inverted confocal laser scanning microscope. In terms of controlled deformation, the conception and technical solutions achieve a high level of accuracy. Moreover, user-friendly software has been developed to control both shear flow parameters and temperature. The validation of specifications as well as the three modes of motion was carried out, first of all without a sample, and then by tracking fluorescent particles in a model system, in our case a micro-gel. Real values agreed well with those we targeted. In addition, an experiment with bread dough deformation under shear flow was initiated to gain some insight into the potential use of our device. These results show that the RheOptiCAD® promises to be a useful tool to better understand, from both a fundamental and an industrial point of view, the rheological behavior of the microstructure of complex fluids under controlled thermo-mechanical parameters in the case of food and non
Periodically-modulated inhibition of living pacemaker neurons--III. The heterogeneity of the postsynaptic spike trains, and how control parameters affect it.
Segundo, J P; Vibert, J F; Stiber, M
Codings involving spike trains at synapses with inhibitory postsynaptic potentials on pacemakers were examined in crayfish stretch receptor organs by modulating presynaptic instantaneous rates periodically (triangles or sines; frequencies, slopes and depths under, respectively, 5.0 Hz, 40.0/s/s and 25.0/s). Timings were described by interspike and cross-intervals ("phases"); patterns (dispersions, sequences) and forms (timing classes) were identified using pooled graphs (instant along the cycle when a spike occurs vs preceding interval) and return maps (plots of successive intervals). A remarkable heterogeneity of postsynaptic intervals and phases characterizes each modulation. All cycles separate into the same portions: each contains a particular form and switches abruptly to the next. Forms differ in irregularity and predictability: they are (see text) "p:q alternations", "intermittent", "phase walk-throughs", "messy erratic" and "messy stammering". Postsynaptic cycles are asymmetric (hysteresis). This contrasts with the presynaptic homogeneity, smoothness and symmetry. All control parameters are, individually and jointly, strongly influential. Presynaptic slopes, say, act through a postsynaptic sensitivity to their magnitude and sign; when increasing, hysteresis augments and forms change or disappear. Appropriate noise attenuates between-train contrasts, providing modulations are under 0.5 Hz. Postsynaptic natural intervals impose critical time bases, separating presynaptic intervals (around, above or below them) with dissimilar consequences. Coding rules are numerous and have restricted domains; generalizations are misleading. Modulation-driven forms are trendy pacemaker-driven forms. However, dissimilarities, slight when patterns are almost pacemaker, increase as inhibition departs from pacemaker and incorporate unpredictable features. Physiological significance-(1) Pacemaker-driven forms, simple and ubiquitous, appear to be elementary building blocks of synaptic codings, present always but in each case distorted typically. (2) Synapses are prototype: similar behaviours should be widespread, and networks simulations benefit by nonlinear units generating all forms. (3) Relevant to periodic functions are that few variables need be involved in form selection, that distortions are susceptible to noise levels and, if periods are heterogeneous, that simple input cycles impose heterogeneous outputs. (4) Slow Na inactivations are necessary for obtaining complex forms and hysteresis. Formal significance--(1) Pacemaker-driven forms and presumably their modulation-driven counterparts, pertain to universal periodic, intermittent, quasiperiodic and chaotic categories whose formal properties carry physiological connotations. (2) Only relatively elaborate, nonlinear geometric models show all forms; simpler ones, show only alternations and walk-throughs. (3) Bifurcations resemble those of simple maps that can provide useful guidelines. (4) Heterogeneity poses the unanswered question of whether or not the entire cycle and all portions have the same behaviours: therefore, whether trajectories are continuous or have discontinuities and/or singular points.
Chemical evolution of dissolved inorganic carbon species flowing in thin water films and its implications for (rapid) degassing of CO2 during speleothem growth
NASA Astrophysics Data System (ADS)
Hansen, Maximilian; Dreybrodt, Wolfgang; Scholz, Denis
Rapid degassing of CO2 from a thin film of drip water on the surface of stalagmites is often considered to have a large effect on both speleothem growth and stable isotope values and is offered as an explanation for higher δ13C and δ18O values than expected under conditions of stable isotope equilibrium. However, the time constant for degassing of CO2 from the solution only depends on film thickness and the coefficient of molecular diffusion for CO2. Thus, for thin films, the time for degassing of CO2 is much shorter than the time for subsequent equilibration of the dissolved carbon species and precipitation of CaCO3. In this context, degassing of CO2 is always fast. Here we present three experiments that enable the determination of the time constants for degassing of CO2, τdeg, subsequent equilibration to a new pCO2, τeq, and precipitation of CaCO3, τpr, in a thin film of an H2O-CO2-CaCO3 solution flowing on a calcite surface. The experiments are performed under cave-analogue conditions. At a temperature of 20 °C and for a film thickness of δ ≈ 0.01 cm, τdeg ≈ 2 s. τeq ≈ 13 s and, thus, one order of magnitude larger. Finally, τpr ≈ 400 s for δ ≈ 0.01 cm, again one order of magnitude larger. The experimentally determined values for τdeg, τeqτpr are in good agreement with the theoretical predictions. Our results confirm that the chemical evolution of the drip water proceeds in three subsequent major steps. During the first step of degassing of CO2, pH and Ca2+ concentration remain almost constant. During equilibration to the lower pCO2 of the solution, pH increases to about 8 whereas the Ca2+ concentration still remains constant. Finally, during precipitation of calcite, pCO2 remains at its low level and pH decreases slightly. These results suggest that the drip rate may have an important influence on the stable isotope signals recorded in speleothems. Stalagmites growing beneath drip sites with stable, intermediate drip rates (i.e., in the
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
High-Resolution Audio with Inaudible High-Frequency Components Induces a Relaxed Attentional State without Conscious Awareness
Kuribayashi, Ryuma; Nittono, Hiroshi
High-resolution audio has a higher sampling frequency and a greater bit depth than conventional low-resolution audio such as compact disks. The higher sampling frequency enables inaudible sound components (above 20 kHz) that are cut off in low-resolution audio to be reproduced. Previous studies of high-resolution audio have mainly focused on the effect of such high-frequency components. It is known that alpha-band power in a human electroencephalogram (EEG) is larger when the inaudible high-frequency components are present than when they are absent. Traditionally, alpha-band EEG activity has been associated with arousal level. However, no previous studies have explored whether sound sources with high-frequency components affect the arousal level of listeners. The present study examined this possibility by having 22 participants listen to two types of a 400-s musical excerpt of French Suite No. 5 by J. S. Bach (on cembalo, 24-bit quantization, 192 kHz A/D sampling), with or without inaudible high-frequency components, while performing a visual vigilance task. High-alpha (10.5–13 Hz) and low-beta (13–20 Hz) EEG powers were larger for the excerpt with high-frequency components than for the excerpt without them. Reaction times and error rates did not change during the task and were not different between the excerpts. The amplitude of the P3 component elicited by target stimuli in the vigilance task increased in the second half of the listening period for the excerpt with high-frequency components, whereas no such P3 amplitude change was observed for the other excerpt without them. The participants did not distinguish between these excerpts in terms of sound quality. Only a subjective rating of inactive pleasantness after listening was higher for the excerpt with high-frequency components than for the other excerpt. The present study shows that high-resolution audio that retains high-frequency components has an advantage over similar and indistinguishable digital
NuSTAR observations of the state transition of millisecond pulsar binary PSR J1023+0038
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
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.
Arne - Exploring the Mare Tranquillitatis Pit
NASA Astrophysics Data System (ADS)
Robinson, M. S.; Thangavelautham, J.; Wagner, R.; Hernandez, V. A.; Finch, J.
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
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.
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.
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.
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
Protons, the thylakoid membrane, and the chloroplast ATP synthase.
Junge, W
of heuristic value to visualize CFoCF1 as a mechanical coupling device. Its maximum turnover number ranges up to 400 s-1 for ATP and 1200 s-1 for protons. At about 200 mV electric driving force this implied a conductance of about 1 fS. Its channel portion (CFo), however, has revealed a very large protonic conductance of 1 pS (three orders of magnitude greater than the protonic conductance of gramicidin around neutral pH). (6) The sight and smell of food increased LH serotonin release; this effect was detectable when local fluoxetine was used to block serotonin reuptake.(ABSTRACT TRUNCATED AT 400 WORDS)
GPR investigation of tephra fallout, Cerro Negro volcano, Nicaragua: a method for constraining parameters used in tephra sedimentation models
NASA Astrophysics Data System (ADS)
Courtland, L. M.; Kruse, S. E.; Connor, C. B.; Connor, L. J.; Savov, I. P.; Martin, K. T.
km and the deposit is thicker than expected based on thinning trends observed in the proximal zone of the deposit. This overthickening of the tephra blanket, defining the transition from proximal to medial depositional facies, is indicative of transition from sedimentation dominated by fallout from plume margins to that dominated by fallout from the buoyant eruption cloud—a feature of deposits previously identified in larger-volume eruptions. We interpret this change to represent a change in diffusion law, occurring at total particle fall times (the fall time threshold of numerical models) of ~400 s. Thus, the detailed GPR profiles and pit data collected at Cerro Negro help to validate current numerical models of tephra sedimentation.
High-Resolution Audio with Inaudible High-Frequency Components Induces a Relaxed Attentional State without Conscious Awareness.
Kuribayashi, Ryuma; Nittono, Hiroshi
High-resolution audio has a higher sampling frequency and a greater bit depth than conventional low-resolution audio such as compact disks. The higher sampling frequency enables inaudible sound components (above 20 kHz) that are cut off in low-resolution audio to be reproduced. Previous studies of high-resolution audio have mainly focused on the effect of such high-frequency components. It is known that alpha-band power in a human electroencephalogram (EEG) is larger when the inaudible high-frequency components are present than when they are absent. Traditionally, alpha-band EEG activity has been associated with arousal level. However, no previous studies have explored whether sound sources with high-frequency components affect the arousal level of listeners. The present study examined this possibility by having 22 participants listen to two types of a 400-s musical excerpt of French Suite No. 5 by J. S. Bach (on cembalo, 24-bit quantization, 192 kHz A/D sampling), with or without inaudible high-frequency components, while performing a visual vigilance task. High-alpha (10.5-13 Hz) and low-beta (13-20 Hz) EEG powers were larger for the excerpt with high-frequency components than for the excerpt without them. Reaction times and error rates did not change during the task and were not different between the excerpts. The amplitude of the P3 component elicited by target stimuli in the vigilance task increased in the second half of the listening period for the excerpt with high-frequency components, whereas no such P3 amplitude change was observed for the other excerpt without them. The participants did not distinguish between these excerpts in terms of sound quality. Only a subjective rating of inactive pleasantness after listening was higher for the excerpt with high-frequency components than for the other excerpt. The present study shows that high-resolution audio that retains high-frequency components has an advantage over similar and indistinguishable digital sound
Dust devils as aeolian transport mechanisms in southern Nevada and the Mars Pathfinder landing site
NASA Astrophysics Data System (ADS)
Metzger, Stephen M.
Discovery of dust devils vortices in Mars Pathfinder images by this study is direct evidence of a dust entrainment mechanism at work on Mars. Dust devils on Earth can entrain fine material from crusted as well as unconsolidated surfaces, even when forced-convection wind speeds are below threshold. Terrestrial dust devils are commonly ``squat'' V-shaped vortices lasting several minutes. Well developed vortices consist of an outer cylinder of high rotation (<25 m/s), an Intermediate cylinder of moderate vertical lift (<13 m/s), and a inner cylindrical core of low pressure (<1.5% below ambient pressure) and elevated temperature (up to 20°C above ambient air temperature). Directly sampled dust devils on Earth were found to carry from 30 to over 2000 kg of soil. On average, the Eldorado Valley, NV, experienced 42 observable dust devils per summer day, each lofting over 200 kg for a daily total of 9 metric tonnes from this desert basin. Spectral differencing techniques have enhanced five localized dust plumes against the general haze in Mars Pathfinder images acquired near midday, which are determined to be dust devils. Given interpreted geographic locations relative to the lander, the dust devils are 14 to 79 m wide, 46 to over 350 m tall, and travel over ground at 0.5 to 4.6 m/s. Their dust loading was approximately 7 × 10-5 kg/m3, relative to the general haze of 9 × 10-8 kg/m3. With an estimated vertical dust flux of 0.5 g m-2 s-1, total particulate transport of these Martian dust devils may have ranged from 2.2 kg for a small dust devil lasting 35 s to over 700 kg for a large plume of 400 s duration. Observed characteristics of these plumes are consistent with expectations based on theory and the lessons of terrestrial field studies. The increasingly apparent role of dust devils in the dust aeolian transport cycle may largely explain the continued concentration of the general Martian dust haze and perhaps the Initiation mechanism for global dust storms.
Transient tension changes initiated by laser temperature jumps in rabbit psoas muscle fibres.
Goldman, Y E; McCray, J A; Ranatunga, K W
1. A technique was developed to generate 2-8 degrees C step temperature perturbations (T-jumps) in single muscle fibres to study the thermodynamics of muscle contraction. A solid-state pulsed holmium laser emitting at 2.065 microns heated the fibre and surrounding solution in approximately 150 mus. The signal from a 100 microns thermocouple fed back to a heating wire maintained the elevated temperature after the laser pulse. 2. Tension of glycerol-extracted muscle fibres from rabbit psoas muscle did not change significantly following T-jumps when the fibre was relaxed. 3. In rigor, tension decreased abruptly on heating indicating normal (not rubber-like) thermoelasticity. The thermoelastic coefficient (negative ratio of relative length change to relative temperature change) of the fibre was estimated to be -0.021 at sarcomere lengths of 2.5-2.8 microns. Rigor tension was constant after the temperature step and returned to the original value on recooling. 4. In maximal Ca2+ activation, tension transients initiated by T-jumps had several phases. An immediate tension decrease suggests that thermoelasticity during contraction is similar to that in rigor. Active tension then recovered to the value before the T-jump with an apparent rate constant of approximately 400 s-1 (at 10-20 degrees C). This rate constant did not have an appreciable dependence on the final temperature. Finally, tension increased exponentially to a new higher level with a rate constant of approximately 20 s-1 at 20 degrees C. This rate constant increased with temperature with a Q10 of 1.4. 5. At submaximal Ca2+ activation the tension rise was followed by a decay to below the value before the T-jump. This decline was expected from the temperature dependence of steady pCa-tension curves. The final tension decline occurred on the 1-5 s time scale. 6. The value and amplitude dependence of the rate constant for the quick recovery following T-jumps were similar to those of the quick recovery following
Conceptual Design, Implementation and Commissioning of Data Acquisition and Control System for Negative Ion Source at IPR
Soni, Jignesh; Gahlaut, A.; Bansal, G.; Parmar, K. G.; Pandya, K.; Chakraborty, A.; Yadav, Ratnakar; Singh, M. J.; Bandyopadhyay, M.
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
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.
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
Abnormal N400 word repetition effects in fragile X-associated tremor/ataxia syndrome.
Olichney, John M; Chan, Shiaohui; Wong, Ling M; Schneider, Andrea; Seritan, Andreea; Niese, Adam; Yang, Jin-Chen; Laird, Kelsey; Teichholtz, Sara; Khan, Sara; Tassone, Flora; Hagerman, Randi
.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).
Seismoacoustic analysis of Ultra-Long-Period Signals Generated in the Atmosphere during the 2009 Eruption of Redoubt Volcano, Alaska
NASA Astrophysics Data System (ADS)
Lyons, J. J.; Haney, M. M.; Van Eaton, A. R.; Schwaiger, H. F.; Schneider, D. J.
We investigate a novel recording of volcanically-generated atmospheric gravity waves on multiple (proximal) stations during the 2009 eruptive activity of Redoubt Volcano, Alaska. From March 23 - April 4, 2009, 16 of the 19 ash-generating explosions reached the stratosphere (>10 km asl.), and a subset of these explosions produced significant ultra-long-period (ULP) seismic signals at periods greater than 250 s. The ULP signals were recorded on a temporary network of seismometers (0.033 - 50 Hz) and a single permanent infrasound sensor (0.1 - 50 Hz) all located within 12 kilometers of the active vent. The ULP signals have delayed arrivals following explosion onsets in both the seismic and infrasound data, indicating that they are generated in the atmosphere. The atmosphere sustains two types of ULP signals: acoustic waves and gravity waves. ULP acoustic waves are mostly controlled by the compressibility of the atmosphere, travel close to the speed of sound, and have a maximum period limited by the acoustic cut-off frequency of about 300 s. Gravity waves are buoyancy-controlled oscillations set up by the disruption of the normal density stratification of the atmosphere, typically have periods greater than 300 s and phase velocities of 10s of m/s. We observe a range in peak ULP energy (300 - 400+ s) that suggests both types of ULP signals were generated by the Redoubt explosions, but that gravity waves dominate for some of the explosions. Moreover, we see moveout velocities of 10s of m/s for some events and acoustic speeds for others since the ULP signals were recorded across the local network. In addition to signals on the vertical components, high amplitude signals are also recorded on the horizontal components. Since we are dealing with signals in the tilt-dominated portion of the seismometer response, the horizontal components are converted to tilt and we observe multiple tilt cycles at periods similar to the ULP signals. These signals indicate tilts of 10s-100s of
Remote Love Wave Triggering of Tremor in the Nankai Subduction Zone: New Observations and Dynamic Stress Modeling
NASA Astrophysics Data System (ADS)
Enescu, B.; Chao, K.; Obara, K.; Peng, Z.; Matsuzawa, T.; Yagi, Y.
case of the 2012 Sumatra earthquake, we found a high correlation between the Love waves dynamic Coulomb stress change at the tremor source and the triggered NVT, for a time period of about 400s, which starts from the first Love wave cycles. Afterwards, the tremor bursts have slightly larger amplitudes and the correlation with the surface waves becomes poor. Preliminary results indicate a shallower location for these later tremors. Our results indicate that the triggering mechanism of NVT in western Shikoku is essentially the same with the one operating (e.g., Hill, 2012) in other subduction regions around the world (e.g., Cascadia). The tremor responds to excitation by both Love and Rayleigh waves according to the Coulomb failure criterion; failure, once underway, might be controlled by other mechanisms (e.g., some form of rate-state friction), which we plan to address in future studies.
Regulation of polyhydroxybutyrate accumulation in Sinorhizobium meliloti by the trans-encoded small RNA MmgR.
Lagares, Antonio; Ceizel Borella, Germán; Linne, Uwe; Becker, Anke; Valverde, Claudio
Riboregulation has a major role in the fine-tuning of multiple bacterial processes. Among the RNA players, trans-encoded untranslated small RNAs (sRNAs) regulate complex metabolic networks by tuning expression from multiple target genes in response to numerous signals. In Sinorhizobium meliloti, over 400 sRNAs are expressed under different stimuli. The sRNA MmgR-standing for Makes more granules Regulator-has been of particular interest to us since its sequence and structure are highly conserved among the α-proteobacteria, and its expression is regulated by the amount and quality of the bacterium's available nitrogen source. In this work, we explored the biological role of MmgR in S. meliloti 2011 by characterizing the effect of a deletion of the internal conserved core of mmgR (mmgR(Δ33-51)). This mutation resulted in higher amounts of polyhydroxybutyrate (PHB) distributed into more intracellular granules than are found in the wild-type strain. This phenotype was expressed upon cessation of balanced growth owing to a nitrogen depletion in the presence of surplus carbon (i. e., at a carbon:nitrogen molar ratio greater than 10). The normal PHB accumulation was complemented with a wild-type mmgR copy, but not with unrelated sRNA genes. Furthermore, the expression of mmgR limited PHB accumulation in the wild-type, regardless of the magnitude of the C surplus. Quantitative proteomic profiling and qRT-PCR revealed that the absence of MmgR results in a posttranscriptional overexpression of both PHB-phasin proteins (PhaP1, PhaP2). All together, our results indicate that the widely conserved α-proteobacterial MmgR sRNA fine-tunes the regulation of PHB storage in S. meliloti IMPORTANCE: High-throughput RNA sequencing has recently uncovered an overwhelming number of trans-encoded small RNAs (sRNAs) in diverse prokaryotes. In the nitrogen-fixing α-proteobacterial symbiont of alfalfa root nodules Sinorhizobium meliloti, only four out of hundreds of identified sRNA genes
The amino-acid substituents of dipeptide substrates of cathepsin C can determine the rate-limiting steps of catalysis.
Rubach, Jon K; Cui, Guanglei; Schneck, Jessica L; Taylor, Amy N; Zhao, Baoguang; Smallwood, Angela; Nevins, Neysa; Wisnoski, David; Thrall, Sara H; Meek, Thomas D
We examined the cathepsin C-catalyzed hydrolysis of dipeptide substrates of the form Yaa-Xaa-AMC, using steady-state and pre-steady-state kinetic methods. The substrates group into three kinetic profiles based upon the broad range observed for k(cat)/K(a) and k(cat) values, pre-steady-state time courses, and solvent kinetic isotope effects (sKIEs). The dipeptide substrate Gly-Arg-AMC displayed large values for k(cat)/K(a) (1.6 ± 0.09 μM(-1) s(-1)) and k(cat) (255 ± 6 s(-1)), an inverse sKIE on k(cat)/K(a) ((D)(k(cat)/K(a)) = 0.6 ± 0.15), a modest, normal sKIE on k(cat) ((D)k(cat) = 1.6 ± 0.2), and immeasurable pre-steady-state kinetics, indicating an extremely fast pre-steady-state rate (>400 s(-1)). (Errors on fitted values are omitted in the text for clarity but may be found in Table 2.) These results conformed to a kinetic model where the acylation (k(ac)) and deacylation (k(dac)) half-reactions are very fast and similar in value. The second substrate type, Gly-Tyr-AMC and Ser-Tyr-AMC, the latter the subject of a comprehensive kinetic study (Schneck et al. (2008) Biochemistry 47, 8697-8710), were found to be less active substrates compared to Gly-Arg-AMC, with respective k(cat)/K(a) values of 0.49 ± 0.07 μM(-1 )s(-1) and 5.3 ± 0.5 μM(-1 )s(-1), and k(cat) values of 28 ± 1 s(-1) and 25 ± 0.5 s(-1). Solvent kinetic isotope effects for Ser-Tyr-AMC were found to be inverse for k(cat)/K(a) ((D)(k(cat)/K(a)) = 0.74 ± 0.05) and normal for k(cat) ((D)k(cat) = 2.3 ± 0.1) but unlike Gly-Arg-AMC, pre-steady-state kinetics of Gly-Tyr-AMC and Ser-Tyr-AMC were measurable and characterized by a single-exponential burst, with fast transient rates (490 s(-1) and 390 s(-1), respectively), from which it was determined that k(ac) ≫ k(dac) ∼ k(cat). The third substrate type, Gly-Ile-AMC, gave very low values of k(cat)/K(a) (0.0015 ± 0.0001 μM(-1) s(-1)) and k(cat) (0.33 ± 0.02 s(-1)), no sKIEs, ((D)(k(cat)/K(a)) = 1.05 ± 0.5 and (D)k(cat) = 1.06 ± 0.4), and
The interannual earthquake distributions and its peculiarity.
NASA Astrophysics Data System (ADS)
Levin, Boris; Sasorova, Elena
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