Science.gov

Sample records for powerful pure nebular

  1. Optical Transients Powered by Magnetars: Dynamics, Light Curves, and Transition to the Nebular Phase

    NASA Astrophysics Data System (ADS)

    Wang, Ling-Jun; Wang, S. Q.; Dai, Z. G.; Xu, Dong; Han, Yan-Hui; Wu, X. F.; Wei, Jian-Yan

    2016-04-01

    Millisecond magnetars can be formed via several channels: core collapse of massive stars, accretion-induced collapse of white dwarfs (WDs), double WD mergers, double neutron star (NS) mergers, and WD-NS mergers. Because the mass of ejecta from these channels could be quite different, their light curves are also expected to be diverse. We evaluate the dynamic evolution of optical transients powered by millisecond magnetars. We find that the magnetar with a short spin-down timescale converts its rotational energy mostly into the kinetic energy of the transient, while the energy of a magnetar with a long spin-down timescale goes into radiation of the transient. This leads us to speculate that hypernovae could be powered by magnetars with short spin-down timescales. At late times the optical transients will gradually evolve into a nebular phase because of the photospheric recession. We treat the photosphere and nebula separately because their radiation mechanisms are different. In some cases the ejecta could be light enough that the magnetar can accelerate it to a relativistic speed. It is well known that the peak luminosity of a supernova (SN) occurs when the luminosity is equal to the instantaneous energy input rate, as shown by Arnett. We show that photospheric recession and relativistic motion can modify this law. The photospheric recession always leads to a delay of the peak time {t}{pk} relative to the time {t}× at which the SN luminosity equals the instantaneous energy input rate. Relativistic motion, however, may change this result significantly.

  2. Nebular Paleomagnetism

    NASA Astrophysics Data System (ADS)

    Fu, R. R.; Weiss, B. P.; Andrade Lima, E.; Harrison, R. J.; Bai, X. N.; Ebel, D. S.; Suavet, C. R.; Wang, H.

    2014-12-01

    Theoretical work suggests that magnetic fields play a fundamental role in the evolution of protoplanetary systems. Efficient radial transport of angular momentum in the protoplanetary disk, an essential requirement for the formation of stars and planets, may be mediated by the magneto-rotational instability (MRI) or magnetocentrifugal winds (MCW). Magnetic fields may also generate turbulence in the nebular gas, potentially leading to instabilities that created the first planetesimals. Finally, magnetic reconnection events may lead to the formation of chondrules, which are millimeter-sized meteoritic inclusions that likely constituted a major building block of terrestrial planets in the solar system. Direct measurements of the magnetic field in the planet-forming region of a protoplanetary disk, which have remained hitherto elusive to astronomical observations, are necessary to test the theoretical models discussed above. Because chondrules were heated and cooled in the nebula, they potentially carry a record of nebular magnetic fields. Newly developed microsampling and magnetic field mapping techniques based on the SQUID microscope can measure very weak moments (<10-13 Am2) from oriented small (~100 μm) samples, enabling the recovery of detailed paleomagnetic data from single chondrules. We performed paleomagnetic experiments on 13 chondrules from the primitive LL3.0 chondrite Semarkona. We showed that dusty olivine-bearing chondrules (Fig. 1) were magnetized prior to the assembly of the meteorite in a magnetic field of 54±21 μT. This field strength provides evidence against chondrule formation near the sun as predicted by the x-wind model while favoring weak-field processes such as nebular shocks or planetesimal collisions. Furthermore, such fields are sufficient to redistribute angular momentum efficiently via either the MRI or MCW, strongly suggesting that magnetic fields are the primary driver of mass accretion in protoplanetary disks. Ongoing paleomagnetic

  3. Cometary Refractory Grains: Interstellar and Nebular Sources

    NASA Astrophysics Data System (ADS)

    Wooden, D. H.

    2008-07-01

    with asteroids, the Stardust Fe-bearing and Fe-rich crystalline silicates suggests partial aqueous alteration in comet nuclei. However, aqueous alteration transforms Fe-rich olivine to phyllosilicates before Mg-rich olivine, and Stardust has Mg-rich and Fe-rich olivine and no phyllosilicates. Hence, we look to a nebular source for the moderately Fe-rich to nearly pure-Fe crystalline silicates. Primitive matrices have Mg-Fe silicates but no phyllosilicates, supporting the idea that Mg-Fe silicates but not phyllosilicates are products of water-rich shocks. Chondrule-formation is a late stage process in our protoplanetary disk. Stardust samples show comet 81P/Wild 2 formed at least as late to incorporate a few chondrules, requiring radial transport of chondrules out to perhaps >20 AU. By similar radial transport mechanisms, collisional fragments of aqueously altered asteroids, in particular achondrites that formed earlier than chondrules, might reach the comet-forming zones. However, Stardust samples do not have phyllosilicates and chondrules are rare. Hence, the nebular refractory grains in comet 81P/Wild 2, as well as other comets, appear to be pre-accretionary with respect to asteroid parent bodies. By discussing nebular pathways for the formation of Fe-rich crystalline silicates, and also phyllosilicates and carbonates, we put forth the view that comets contain both the interstellar ingredients for and the products of nebular transmutation.

  4. Superluminous Supernova SN 2015bn in the Nebular Phase: Evidence for the Engine-powered Explosion of a Stripped Massive Star

    NASA Astrophysics Data System (ADS)

    Nicholl, M.; Berger, E.; Margutti, R.; Chornock, R.; Blanchard, P. K.; Jerkstrand, A.; Smartt, S. J.; Arcavi, I.; Challis, P.; Chambers, K. C.; Chen, T.-W.; Cowperthwaite, P. S.; Gal-Yam, A.; Hosseinzadeh, G.; Howell, D. A.; Inserra, C.; Kankare, E.; Magnier, E. A.; Maguire, K.; Mazzali, P. A.; McCully, C.; Milisavljevic, D.; Smith, K. W.; Taubenberger, S.; Valenti, S.; Wainscoat, R. J.; Yaron, O.; Young, D. R.

    2016-09-01

    We present nebular-phase imaging and spectroscopy for the hydrogen-poor superluminous supernova (SLSN) SN 2015bn, at redshift z = 0.1136, spanning +250-400 days after maximum light. The light curve exhibits a steepening in the decline rate from 1.4 mag (100 days)-1 to 1.7 mag (100 days)-1, suggestive of a significant decrease in the opacity. This change is accompanied by a transition from a blue continuum superposed with photospheric absorption lines to a nebular spectrum dominated by emission lines of oxygen, calcium, and magnesium. There are no obvious signatures of circumstellar interaction or large 56Ni mass. We show that the spectrum at +400 days is virtually identical to a number of energetic SNe Ic such as SN 1997dq, SN 2012au, and SN 1998bw, indicating similar core conditions and strengthening the link between “hypernovae”/long gamma-ray bursts and SLSNe. A single explosion mechanism may unify these events that span absolute magnitudes of -22 < M B < -17. Both the light curve and spectrum of SN 2015bn are consistent with an engine-driven explosion ejecting 7-30 M ⊙ of oxygen-dominated ejecta (for reasonable choices in temperature and opacity). A strong and relatively narrow O i λ7774 line, seen in a number of these energetic events but not in normal supernovae, may point to an inner shell that is the signature of a central engine.

  5. Nebular Hydrogen Absorption in the Ejecta of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.; Ishibashi, K.; Davidson, K.; Fisher, Richard R. (Technical Monitor)

    2000-01-01

    Space Telescope Imaging Spectrograph (STIS) observations of Eta Carinae and immediate ejecta reveal narrow Balmer absorption lines in addition to the nebular-scattered broad P-Cygni absorptions. The narrow absorption correlates with apparent disk structure that separates the two Homunculus lobes. We trace these features about half way up the Northern lobe until the scattered stellar Balmer line doppler-shifts redward beyond the nebular absorption feature. Three-dimensional data cubes, made by mapping the Homunculus at Balmer alpha and Balmer beta with the 52 x 0.1 arcsecond aperture and about 5000 spectral resolving power, demonstrate that the absorption feature changes slowly in velocity with nebular position. We have monitored the stellar Balmer alpha line profile of the central source over the past four years. The equivalent width of the nebular absorption feature changes considerably between observations. The changes do not correlate with measured brightness of Eta Carinae. Likely clumps of neutral hydrogen with a scale size comparable to the stellar disk diameter are passing through the intervening light path on the timescales less than several months. The excitation mechanism involves Lyman alpha radiation (possibly the Lyman series plus Lyman continuum) and collisions leading to populating the 2S metastable state. Before the electron can jump to the ground state by two photon emission (lifetime about 1/8 second), a stellar Balmer photon is absorbed and the electron shifts to an NP level. We see the absorption feature in higher Balmer lines, and but not in Paschen lines. Indeed we see narrow nebular Paschen emission lines. At present, we do not completely understand the details of the absorption. Better understanding should lead to improved insight of the unique conditions around Eta Carinae that leads to these absorptions.

  6. Power-based Shift Schedule for Pure Electric Vehicle with a Two-speed Automatic Transmission

    NASA Astrophysics Data System (ADS)

    Wang, Jiaqi; Liu, Yanfang; Liu, Qiang; Xu, Xiangyang

    2016-11-01

    This paper introduces a comprehensive shift schedule for a two-speed automatic transmission of pure electric vehicle. Considering about driving ability and efficiency performance of electric vehicles, the power-based shift schedule is proposed with three principles. This comprehensive shift schedule regards the vehicle current speed and motor load power as input parameters to satisfy the vehicle driving power demand with lowest energy consumption. A simulation model has been established to verify the dynamic and economic performance of comprehensive shift schedule. Compared with traditional dynamic and economic shift schedules, simulation results indicate that the power-based shift schedule is superior to traditional shift schedules.

  7. NuSTAR observations of the TeV detected pulsar wind nebular MSH 15-52 and the Central Power Source PSR B1509-58

    NASA Astrophysics Data System (ADS)

    An, Hongjun

    The X-ray bright rotation-powered pulsar PSR B1509-58 is young, has very strong surface dipolar magnetic field (>10(13) \\ G), and powers the TeV pulsar wind nebula (PWN) MSH 15-52. We report on the pulsar's temporal and spectral properties measured with the Nuclear Spectroscopic Telescope Array (NuSTAR) and compare our results with the previous measurements. The PWN MSH 15-52, powered by the pulsar PSR B1509-58, was well studied in the soft X-ray band (<10 keV), and has many interesting structures in it such as jets and arcs. However, hard X-ray imaging (>10 keV) has not previously been done for this source due to the lack of focusing telescope in that band. We report on the broadband X-ray properties of MSH 15-52 using new observations made with NuSTAR and archival Chandra data. We present images and spatially resolved spectra of the source in the broad X-ray band (0.5-79 keV). We interpret our results using particle outflow models based on advection or diffusion of relativistic pulsar wind electron/positron pairs. Using the models, we infer the properties of the particle outflow and the PWN environment. Furthermore, we present 2-D maps of the spectral parameters: flux, spectral index, and hydrogen column density. Although a 3-D model is required in order to quantitatively interpret the results, we discuss some interesting features we have found thus far in the maps.

  8. Spectral modeling of nebular-phase supernovae

    NASA Astrophysics Data System (ADS)

    Jerkstrand, Anders

    2011-12-01

    Massive stars live fast and die young. They shine furiously for a few million years, during which time they synthesize most of the heavy elements in the universe in their cores. They end by blowing themselves up in a powerful explosion known as a supernova. During this process, the core collapses to a neutron star or a black hole, while the outer layers are expelled with velocities of thousands of kilometers per second. The resulting fireworks often outshine the entire host galaxy for many weeks. The explosion energy is eventually radiated away, but powering of the newborn nebula continues by radioactive isotopes synthesized in the explosion. The ejecta are now quite transparent, and we can see the material produced in the deep interiors of the star. To interpret the observations, detailed spectral modeling is needed. This thesis aims to develop and apply state-of-the-art computational tools for interpreting and modeling supernova observations in the nebular phase. This requires calculation of the physical conditions throughout the nebula, including non-thermal processes from the radioactivity, thermal and statistical equilibrium, as well as radiative transport. The inclusion of multi-line radiative transfer, which we compute with a Monte Carlo technique, represents one of the major advancements presented in this thesis.

  9. SNAP: Spreadsheet Nebular Analysis Package

    NASA Astrophysics Data System (ADS)

    Komljenovic, M.; Krawchuk, C.; McCall, M.; Kingsburgh, R.; Richer, Michael; Stevenson, C.

    1996-12-01

    A flexible and extensible software package for two dimensional nebular analyses has been implemented using Visual Basic within Microsoft Excel (version 5). From a calibrated list of fluxes and errors for each spectral row (or object), the program first identifies the lines by their source ions by referring to wavelengths generated from atomic data. The atomic data used in all the calculations is easily updated or augmented by the user. Colour excesses can be computed from a reddening law and ratio of total to selective extinction of a user's choice. For each spectral row, line fluxes can be corrected for stellar absorption and reddening and reported in a format suitable for publication. Temperatures, densities, emission coefficients, and ionic abundances are computed using an adaptation of the FIVEL five-level atom routine. The user has complete control over which spectral lines are used in an analysis -- there are no pre-ordained methods. Abundance analyses can be performed using physical conditions either measured or specified for each spectrum. Since the software is embedded in Microsoft Excel, graphical representations of the data are easily created, and extended analyses using the full functionality of the spreadsheet are easily implemented.

  10. Nebular spectroscopy of the nearby Type IIb supernova 2011dh

    NASA Astrophysics Data System (ADS)

    Shivvers, Isaac; Mazzali, Paolo; Silverman, Jeffrey M.; Botyánszki, János; Cenko, S. Bradley; Filippenko, Alexei V.; Kasen, Daniel; Van Dyk, Schuyler D.; Clubb, Kelsey I.

    2013-12-01

    We present nebular spectra of the nearby Type IIb supernova (SN) 2011dh taken between 201 and 678 d after core collapse. At these late times, SN 2011dh exhibits strong emission lines including a broad and persistent Hα feature. New models of the nebular spectra confirm that the progenitor of SN 2011dh was a low-mass giant (M ≈ 13-15 M⊙) that ejected ˜ 0.07 M⊙ of 56Ni and ˜ 0.27 M⊙ of oxygen at the time of explosion, consistent with the recent disappearance of a candidate yellow supergiant progenitor. We show that light from the SN location is dominated by the fading SN at very late times (˜ 2 yr) and not, for example, by a binary companion or a background source. We present evidence for interaction between the expanding SN blast wave and a circumstellar medium at late times and show that the SN is likely powered by positron deposition ≳1 yr after explosion. We also examine the geometry of the ejecta and show that the nebular line profiles of SN 2011dh indicate a roughly spherical explosion with aspherical components or clumps.

  11. Entropy-power uncertainty relations: towards a tight inequality for all Gaussian pure states

    NASA Astrophysics Data System (ADS)

    Hertz, Anaelle; Jabbour, Michael G.; Cerf, Nicolas J.

    2017-09-01

    We show that a proper expression of the uncertainty relation for a pair of canonically-conjugate continuous variables relies on entropy power, a standard notion in Shannon information theory for real-valued signals. The resulting entropy-power uncertainty relation is equivalent to the entropic formulation of the uncertainty relation due to Bialynicki-Birula and Mycielski, but can be further extended to rotated variables. Hence, based on a reasonable assumption, we give a partial proof of a tighter form of the entropy-power uncertainty relation taking correlations into account and provide extensive numerical evidence of its validity. Interestingly, it implies the generalized (rotation-invariant) Schrödinger-Robertson uncertainty relation exactly as the original entropy-power uncertainty relation implies Heisenberg relation. It is saturated for all Gaussian pure states, in contrast with hitherto known entropic formulations of the uncertainty principle.

  12. Nebular chemistry and theories of lunar origin

    NASA Technical Reports Server (NTRS)

    Larimer, John W.

    1986-01-01

    The cosmic history of planetary matter is traced from nucleosynthesis through accretion in an attempt to understand the origin of the moon. It is noted that nebular processes must be considered in any theory of lunar origin and that planetary differentiation and volcanism determine the final character of lunar rocks. The moon's unique blend of nebular components suggests that the earth and moon accreted from the same mix of components as the proto-moon orbited the proto-earth, with the earth winning and the moon progressively losing, its solar complement of the components.

  13. NEBULAR: A Simple Synthesis Code for the Hydrogen and Helium Nebular Spectrum

    NASA Astrophysics Data System (ADS)

    Schirmer, Mischa

    2016-11-01

    NEBULAR is a lightweight code to synthesize the spectrum of an ideal, mixed hydrogen and helium gas in ionization equilibrium, over a useful range of densities, temperatures and wavelengths. Free-free, free-bound and two-photon continua are included as well as parts of the H i, He i and He ii line series. NEBULAR interpolates over publicly available data tables; it can be used to easily extract information from these tables without prior knowledge about their data structure. The resulting spectra can be used to e.g., determine equivalent line widths, constrain the contribution of the nebular continuum to a bandpass, and for educational purposes. NEBULAR can resample the spectrum on a user-defined wavelength grid for direct comparison with an observed spectrum; however, it can not be used to fit an observed spectrum.

  14. Comparisons of purely topological model, betweenness based model and direct current power flow model to analyze power grid vulnerability.

    PubMed

    Ouyang, Min

    2013-06-01

    This paper selects three frequently used power grid models, including a purely topological model (PTM), a betweennness based model (BBM), and a direct current power flow model (DCPFM), to describe three different dynamical processes on a power grid under both single and multiple component failures. Each of the dynamical processes is then characterized by both a topology-based and a flow-based vulnerability metrics to compare the three models with each other from the vulnerability perspective. Taking as an example, the IEEE 300 power grid with line capacity set proportional to a tolerance parameter tp, the results show non-linear phenomenon: under single node failures, there exists a critical value of tp = 1.36, above which the three models all produce identical topology-based vulnerability results and more than 85% nodes have identical flow-based vulnerability from any two models; under multiple node failures that each node fails with an identical failure probability fp, there exists a critical fp = 0.56, above which the three models produce almost identical topology-based vulnerability results at any tp ≥ 1, but producing identical flow-based vulnerability results only occurs at fp = . In addition, the topology-based vulnerability results can provide a good approximation for the flow-based vulnerability under large fp, and the priority of PTM and BBM to better approach the DCPFM for vulnerability analysis mainly depends on the value of fp. Similar results are also found for other failure types, other system operation parameters, and other power grids.

  15. Cometary Silicates: Interstellar and Nebular Materials

    NASA Technical Reports Server (NTRS)

    Wooden, Diane H.

    2002-01-01

    Evidence for interstellar material in comets is deduced from IR spectra, insitu measurements of Halley, and chondritic porous interplanetary dust particles (CP IDPs). IR spectra of comets reveal the spectrally active minerals: amorphous carbon, amorphous silicates, and (in some comets) crystalline silicates. Evidence suggests amorphous silicates are of interstellar origin while crystalline silicates are of nebular origin. 10 microns spectra of comets and submicron amorphous silicate spherules in CP IDPs have shapes similar to lines-of-sight through the ISM. Thermal emission models of cometary IR spectra require Fe-bearing amorphous silicates. Fe-bearing amorphous silicates may be Fe-bearing crystalline silicates formed in AGB outflows that are amorphized through He+ ion bombardment in supernova shocks in the ISM. Crystalline silicates in comets, as revealed by IR spectra, and their apparent absence in the ISM, argues for their nebular origin. The high temperatures (less than l000 K) at which crystals form or are annealed occur in the inner nebula or in nebular shocks in the 5-10 AU region. Oxygen isotope studies of CP IDPs show by mass only 1 % of the silicate crystals are of AGB origin. Together this suggests crystalline silicates in comets are probably primitive grains from the early solar nebula.

  16. Evaporation of nebular fines during chondrule formation

    NASA Astrophysics Data System (ADS)

    Wasson, John T.

    2008-06-01

    Studies of matrix in primitive chondrites provide our only detailed information about the fine fraction (diameter <2 μm) of solids in the solar nebula. A minor fraction of the fines, the presolar grains, offers information about the kinds of materials present in the molecular cloud that spawned the Solar System. Although some researchers have argued that chondritic matrix is relatively unaltered presolar matter, meteoritic chondrules bear witness to multiple high-temperature events each of which would have evaporated those fines that were inside the high-temperature fluid. Because heat is mainly transferred into the interior of chondrules by conduction, the surface temperatures of chondrules were probably at or above 2000 K. In contrast, the evaporation of mafic silicates in a canonical solar nebula occurs at around 1300 K and FeO-rich, amorphous, fine matrix evaporates at still lower temperatures, perhaps near 1200 K. Thus, during chondrule formation, the temperature of the placental bath was probably >700 K higher than the evaporation temperatures of nebular fines. The scale of chondrule forming events is not known. The currently popular shock models have typical scales of about 10 km. The scale of nebular lightning is less well defined, but is certainly much smaller, perhaps in the range 1 to 1000 m. In both cases the temperature pulses were long enough to evaporate submicrometer nebular fines. This interpretation disagrees with common views that meteoritic matrix is largely presolar in character and CI-chondrite-like in composition. It is inevitable that presolar grains (both those recognized by their anomalous isotopic compositions and those having solar-like compositions) that were within the hot fluid would also have evaporated. Chondrule formation appears to have continued down to the temperatures at which planetesimals formed, possibly around 250 K. At temperatures >600 K, the main form of C is gaseous CO. Although the conversion of CO to CH 4 at lower

  17. ALIEN: A nebular spectra analysis software

    NASA Astrophysics Data System (ADS)

    Cook, R.; Vazquez, R.

    2000-11-01

    A new C-coded software, designed to analyze nebular spectra, is presented. T his software is able to read the fluxes of the most important ions directly from IRAF's output file (splot.log). Spectra can be dereddened using the Balmer lines ratio and the Seaton's extinction law. Electron temperature and density, as well as ionic abundances by number are estimated by means of numeric calculations based on the five-level atom model. The dereddened spectra and the table containing the ionic abundances can be saved in a LaTex formatted file. This software has been initially designed to work with a low dispersion spectra.

  18. Inactivation of Byssochlamys nivea ascospores in strawberry puree by high pressure, power ultrasound and thermal processing.

    PubMed

    Evelyn; Silva, F V M

    2015-12-02

    Byssochlamys nivea is a mold that can spoil processed fruit products and produce mycotoxins. In this work, high pressure processing (HPP, 600 MPa) and power ultrasound (24 kHz, 0.33 W/mL; TS) in combination with 75°C for the inactivation of four week old B. nivea ascospores in strawberry puree for up to 30 min was investigated and compared with 75°C thermal processing alone. TS and thermal processing can activate the mold ascospores, but HPP-75°C resulted in 2.0 log reductions after a 20 min process. For a 10 min process, HPP-75°C was better than 85°C alone in reducing B. nivea spores (1.4 vs. 0.2 log reduction), demonstrating that a lower temperature in combination with HPP is more effective for spore inactivation than heat alone at a higher temperature. The ascospore inactivation by HPP-thermal, TS and thermal processing was studied at different temperatures and modeled. Faster inactivation was achieved at higher temperatures for all the technologies tested, indicating the significant role of temperature in spore inactivation, alone or combined with other physical processes. The Weibull model described the spore inactivation by 600 MPa HPP-thermal (38, 50, 60, 75°C) and thermal (85, 90°C) processing, whereas the Lorentzian model was more appropriate for TS treatment (65, 70, 75°C). The models obtained provide a useful tool to design and predict pasteurization processes targeting B. nivea ascospores.

  19. Investigation of the Statistics of Pure Tone Sound Power Injection from Low Frequency, Finite Sized Sources in a Reverberant Room

    NASA Technical Reports Server (NTRS)

    Smith, Wayne Farrior

    1973-01-01

    The effect of finite source size on the power statistics in a reverberant room for pure tone excitation was investigated. Theoretical results indicate that the standard deviation of low frequency, pure tone finite sources is always less than that predicted by point source theory and considerably less when the source dimension approaches one-half an acoustic wavelength or greater. A supporting experimental study was conducted utilizing an eight inch loudspeaker and a 30 inch loudspeaker at eleven source positions. The resulting standard deviation of sound power output of the smaller speaker is in excellent agreement with both the derived finite source theory and existing point source theory, if the theoretical data is adjusted to account for experimental incomplete spatial averaging. However, the standard deviation of sound power output of the larger speaker is measurably lower than point source theory indicates, but is in good agreement with the finite source theory.

  20. Revealing the binary origin of Type Ic superluminous supernovae through nebular hydrogen emission

    NASA Astrophysics Data System (ADS)

    Moriya, Takashi J.; Liu, Zheng-Wei; Mackey, Jonathan; Chen, Ting-Wan; Langer, Norbert

    2015-12-01

    We propose that nebular Hα emission, as detected in the Type Ic superluminous supernova iPTF13ehe, stems from matter that is stripped from a companion star when the supernova ejecta collide with it. The temporal evolution, the line broadening, and the overall blueshift of the emission are consistent with this interpretation. We scale the nebular Hα luminosity predicted for Type Ia supernovae in single-degenerate systems to derive the stripped mass required to explain the Hα luminosity of iPTF13ehe. We find a stripped mass of 0.1-0.9 solar masses, assuming that the supernova luminosity is powered by radioactivity or magnetar spin down. Because a central heating source is required to excite the Hα emission, an interaction-powered model is not favored for iPTF13ehe if the Hα emission is from stripped matter. We derive a companion mass of more than 20 solar masses and a binary separation of less than about 20 companion radii based on the stripping efficiency during the collision, indicating that the supernova progenitor and the companion formed a massive close binary system. If Type Ic superluminous supernovae generally occur in massive close binary systems, the early brightening observed previously in several Type Ic superluminous supernovae may also be due to the collision with a close companion. Observations of nebular hydrogen emission in future Type Ic superluminous supernovae will enable us to test this interpretation.

  1. Mineral equilibrium in fractionated nebular systems

    NASA Technical Reports Server (NTRS)

    Wood, John A.; Hashimoto, Akihiko

    1993-01-01

    We investigated the equilibrium mineral assemblages in chemically fractionated nebular systems, using a computer routine that finds the set of minerals and gases which minimizes the Gibbs free energy of a system with stipulated elemental abundances. Diagrams are presented showing the equilibrium mineralogy, as a function of temperature (400-2300 K), for unfractionated solar material and five fractionated systems. The fractionated systems were defined by mixing, in various proportions, the following four volatility components that solar material can be divided into: refractory dust, carbonaceous matter, ices, and H2 gas. Dust enrichment is seen to increase temperatures of condensation/evaporation and the Fe(2+) content of mafic minerals and to permit existence of stable melt phases. Enrichment of dust and organic matter produces mineral assemblages that are similar in many ways to those of enstatite chondrites, but with mafic minerals that are far more reduced than those in primitive enstatite chondrites. Enrichment of dust, organics, and ices leads to highly ferrous mineralogies even at the highest temperatures but does not predict the stability of hydrous phases above about 450 K.

  2. Nebular UV Absorption Lines in Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Dinerstein, Harriet

    We propose to continue our Cycle 1 program of studying the Lyman and Werner bands of H_2, seen in absorption against the UV continua of planetary nebula central stars, which arise within neutral-molecular envelopes surrounding the ionized gas. These are the pump lines for a fluorescent cascade of near-infrared emission lines which are observed in many planetary nebulae. By observing the UV lines we can probe the chemical and thermal structure of the envelopes, as well as measure molecular column densities and clarify the excitation processes for the infrared lines. In Cycle 1 we were granted time for three targets, one of which was successfully observed shortly before submission of this proposal. Although the data were not yet available for examination, similar target observed by the project team revealed a rich set of H_2 circumstellar absorption features, demonstrating the feasibility of our program. FUSE spectra also include absorption features from atomic species such as O I and C II, which give rise to important far-infrared fine-structure cooling lines that likewise have been observed from planetary nebulae. In Cycle 2, we add as a secondary goal a search for nebular components of the O VI 032, 1038 AA absorption lines, which trace the presence of hot shocked gas, in nebulae with anomalously strong optical recombination lines of ions of oxygen and nitrogen. This will test a plausible hypothesis for the origin of this anomaly.

  3. Mineral equilibrium in fractionated nebular systems

    NASA Technical Reports Server (NTRS)

    Wood, John A.; Hashimoto, Akihiko

    1993-01-01

    We investigated the equilibrium mineral assemblages in chemically fractionated nebular systems, using a computer routine that finds the set of minerals and gases which minimizes the Gibbs free energy of a system with stipulated elemental abundances. Diagrams are presented showing the equilibrium mineralogy, as a function of temperature (400-2300 K), for unfractionated solar material and five fractionated systems. The fractionated systems were defined by mixing, in various proportions, the following four volatility components that solar material can be divided into: refractory dust, carbonaceous matter, ices, and H2 gas. Dust enrichment is seen to increase temperatures of condensation/evaporation and the Fe(2+) content of mafic minerals and to permit existence of stable melt phases. Enrichment of dust and organic matter produces mineral assemblages that are similar in many ways to those of enstatite chondrites, but with mafic minerals that are far more reduced than those in primitive enstatite chondrites. Enrichment of dust, organics, and ices leads to highly ferrous mineralogies even at the highest temperatures but does not predict the stability of hydrous phases above about 450 K.

  4. Chemoenzymatic Dynamic Kinetic Resolution: A Powerful Tool for the Preparation of Enantiomerically Pure Alcohols and Amines

    PubMed Central

    2015-01-01

    Chemoenzymatic dynamic kinetic resolution (DKR) constitutes a convenient and efficient method to access enantiomerically pure alcohol and amine derivatives. This Perspective highlights the work carried out within this field during the past two decades and pinpoints important avenues for future research. First, the Perspective will summarize the more developed area of alcohol DKR, by delineating the way from the earliest proof-of-concept protocols to the current state-of-the-art systems that allows for the highly efficient and selective preparation of a wide range of enantiomerically pure alcohol derivatives. Thereafter, the Perspective will focus on the more challenging DKR of amines, by presenting the currently available homogeneous and heterogeneous methods and their respective limitations. In these two parts, significant attention will be dedicated to the design of efficient racemization methods as an important means of developing milder DKR protocols. In the final part of the Perspective, a brief overview of the research that has been devoted toward improving enzymes as biocatalysts is presented. PMID:25730714

  5. Chemoenzymatic dynamic kinetic resolution: a powerful tool for the preparation of enantiomerically pure alcohols and amines.

    PubMed

    Verho, Oscar; Bäckvall, Jan-E

    2015-04-01

    Chemoenzymatic dynamic kinetic resolution (DKR) constitutes a convenient and efficient method to access enantiomerically pure alcohol and amine derivatives. This Perspective highlights the work carried out within this field during the past two decades and pinpoints important avenues for future research. First, the Perspective will summarize the more developed area of alcohol DKR, by delineating the way from the earliest proof-of-concept protocols to the current state-of-the-art systems that allows for the highly efficient and selective preparation of a wide range of enantiomerically pure alcohol derivatives. Thereafter, the Perspective will focus on the more challenging DKR of amines, by presenting the currently available homogeneous and heterogeneous methods and their respective limitations. In these two parts, significant attention will be dedicated to the design of efficient racemization methods as an important means of developing milder DKR protocols. In the final part of the Perspective, a brief overview of the research that has been devoted toward improving enzymes as biocatalysts is presented.

  6. Power generation from cellulose using mixed and pure cultures of cellulose-degrading bacteria in a microbial fuel cell.

    PubMed

    Hassan, Sedky H A; Kim, Yong Seong; Oh, Sang-Eun

    2012-10-10

    Microbial fuel cells (MFCs) have been used to generate electricity from various organic compounds such as acetate, glucose, and lactate. We demonstrate here that electricity can be produced in an MFC using cellulose as the electron donor source. Tests were conducted using two-chambered MFCs, the anode medium was inoculated with mixed or pure culture of cellulose-degrading bacteria Nocardiopsis sp. KNU (S strain) or Streptomyces enissocaesilis KNU (K strain), and the catholyte in the cathode compartment was 50mM ferricyanide as catholyte. The power density for the mixed culture was 0.188 mW (188 mW/m(2)) at a current of 0.5mA when 1g/L cellulose was used. However, the power density decreased as the cellulose concentration in the anode compartment decreased. The columbic efficiencies (CEs) ranged from 41.5 to 33.4%, corresponding to an initial cellulose concentration of 0.1-1.0 g/L. For the pure culture, cellobioase enzyme was added to increase the conversion of cellulose to simple sugars, since electricity production is very low. The power densities for S and K strain pure cultures with cellobioase were 162 mW/m(2) and 145 mW/m(2), respectively. Cyclic voltammetry (CV) experiments showed the presence of peaks at 380, 500, and 720 mV vs. Ag/AgCl for the mixed bacterial culture, indicating its electrochemical activity without an external mediator. Furthermore, this MFC system employs a unique microbial ecology in which both the electron donor (cellulose) and the electron acceptor (carbon paper) are insoluble.

  7. Ionic conductivity and thermoelectric power of pure and Al2O3-dispersed AgI

    NASA Technical Reports Server (NTRS)

    Shahi, K.; Wagner, J. B., Jr.

    1981-01-01

    Ionic and electronic conductivities, and thermoelectric power have been measured for AgI and AgI containing a dispersion of submicron size Al2O3 particles. While the dispersion of Al2O3 enhances the ionic conductivity significantly, it does not affect the electronic properties of the matrix. The enhancement is a strong function of the size and concentration of the dispersoid. Various models have been tested to account for the enhanced conduction. However, the complex behavior of the present results points out the need for more sophisticated theoretical models. Ionic conduction and thermoelectric power data suggest that the dispersed Al2O3 generates an excess of cation vacancies and thereby enhances the conductivity and suppresses the thermoelectric power of the matrix. The individual heats of transport of cation interstitials and vacancies have been estimated and compared to their respective migration energies.

  8. Nebular spectra of pair-instability supernovae

    NASA Astrophysics Data System (ADS)

    Jerkstrand, A.; Smartt, S. J.; Heger, A.

    2016-01-01

    If very massive stars (M ≳ 100 M⊙) can form and avoid too strong mass-loss during their evolution, they are predicted to explode as pair-instability supernovae (PISNe). One critical test for candidate events is whether their nucleosynthesis yields and internal ejecta structure, being revealed through nebular-phase spectra at t ≳ 1 yr, match those of model predictions. Here, we compute theoretical spectra based on model PISN ejecta at 1-3 yr post-explosion to allow quantitative comparison with observations. The high column densities of PISNe lead to complete gamma-ray trapping for t ≳ 2 yr which, combined with fulfilled conditions of steady state, leads to bolometric supernova luminosities matching the 56Co decay. Most of the gamma-rays are absorbed by the deep-lying iron and silicon/sulphur layers. The ionization balance shows a predominantly neutral gas state, which leads to emission lines of Fe I, Si I, and S I. For low-mass PISNe, the metal core expands slowly enough to produce a forest of distinct lines, whereas high-mass PISNe expand faster and produce more featureless spectra. Line blocking is complete below ˜5000 Å for several years, and the model spectra are red. The strongest line is typically [Ca II] λλ7291, 7323, one of few lines from ionized species. We compare our models with proposed PISN candidates SN 2007bi and PTF12dam, finding discrepancies for several key observables and thus no support for a PISN interpretation. We discuss distinct spectral features predicted by the models, and the possibility of detecting pair-instability explosions among non-superluminous supernovae.

  9. DETECTION OF DIFFUSE X-RAY EMISSION FROM PLANETARY NEBULAE WITH NEBULAR O VI

    SciTech Connect

    Ruiz, N.; Guerrero, M. A.; Jacob, R.; Schoenberner, D.; Steffen, M.

    2013-04-10

    The presence of O VI ions can be indicative of plasma temperatures of a few Multiplication-Sign 10{sup 5} K that are expected in heat conduction layers between the hot shocked stellar wind gas at several 10{sup 6} K and the cooler (10{sup 4} K) nebular gas of planetary nebulae (PNe). We have used FUSE observations of PNe to search for nebular O VI emission or absorption as a diagnostic of the conduction layer to ensure the presence of hot interior gas. Three PNe showing nebular O VI, namely IC 418, NGC 2392, and NGC 6826, have been selected for Chandra observations and diffuse X-ray emission is indeed detected in each of these PNe. Among the three, NGC 2392 has peculiarly high diffuse X-ray luminosity and plasma temperature compared with those expected from its stellar wind's mechanical luminosity and terminal velocity. The limited effects of heat conduction on the plasma temperature of a hot bubble at the low terminal velocity of the stellar wind of NGC 2392 may partially account for its high plasma temperature, but the high X-ray luminosity needs to be powered by processes other than the observed stellar wind, probably the presence of an unseen binary companion of the central star of the PN (CSPN) of NGC 2392. We have compiled relevant information on the X-ray, stellar, and nebular properties of PNe with a bubble morphology and found that the expectations of bubble models including heat conduction compare favorably with the present X-ray observations of hot bubbles around H-rich CSPNe, but have notable discrepancies for those around H-poor [WR] CSPNe. We note that PNe with more massive central stars can produce hotter plasma and higher X-ray surface brightness inside central hot bubbles.

  10. Strawberry puree processed by thermal, high pressure, or power ultrasound: Process energy requirements and quality modeling during storage.

    PubMed

    Sulaiman, Alifdalino; Farid, Mohammed; Silva, Filipa Vm

    2017-06-01

    Strawberry puree was processed for 15 min using thermal (65 ℃), high-pressure processing (600 MPa, 48 ℃), and ultrasound (24 kHz, 1.3 W/g, 33 ℃). These conditions were selected based on similar polyphenoloxidase inactivation (11%-18%). The specific energies required for the above-mentioned thermal, high-pressure processing, and power ultrasound processes were 240, 291, and 1233 kJ/kg, respectively. Then, the processed strawberry was stored at 3 ℃ and room temperature for 30 days. The constant pH (3.38±0.03) and soluble solids content (9.03 ± 0.25°Brix) during storage indicated a microbiological stability. Polyphenoloxidase did not reactivate during storage. The high-pressure processing and ultrasound treatments retained the antioxidant activity (70%-74%) better than the thermal process (60%), and high-pressure processing was the best treatment after 30 days of ambient storage to preserve antioxidant activity. Puree treated with ultrasound presented more color retention after processing and after ambient storage than the other preservation methods. For the three treatments, the changes of antioxidant activity and total color difference during storage were described by the fractional conversion model with rate constants k ranging between 0.03-0.09 and 0.06-0.22 day (- 1), respectively. In resume, high-pressure processing and thermal processes required much less energy than ultrasound for the same polyphenoloxidase inactivation in strawberry. While high-pressure processing retained better the antioxidant activity of the strawberry puree during storage, the ultrasound treatment was better in terms of color retention.

  11. Possibilities of creating a pure coal-fired power industry based on nanomaterials

    NASA Astrophysics Data System (ADS)

    Zyryanov, V. V.

    2015-08-01

    A concept of distributed multigeneration during combustion of homogenized solid fuels with the addition of oxygen-enriched (to 30-50%) air is proposed. To implement this concept, application of medium-temperature δ-Bi2O3/Ag-nanocermet-based membranes is suggested under low pressures and sweeping of oxygen by the cleaned exit gas or the air. The primary product of the multigeneration is microsphere materials. The heat, the AC and the DC electric energy, the cleaned exit gases with a high CO2 content, and volatile elements adsorbed by the filters are the secondary products. To completely clean the exit gases, which is necessary to implement the distributed multigeneration, an array of successive passive plants is proposed. A thermoelectric module based on a BiTeSb-skutterudite nanocomposite is effective in generation of the DC electric energy at microthermoelectric power plants.

  12. On the Nebular-Phase Spectra of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Kumar, Sahana; Graham, Melissa; Filippenko, Alexei V.

    2017-01-01

    Here we present nebular-phase spectra of 8 Type Ia supernovae. These objects have large host-galaxy offsets and have been observed and studied at early times by LCOGT and KAIT. The nebular-phase spectra presented here were obtained using the Gemini South and Keck telescopes. By analyzing early-time observations and verifying previous predictions for the nebular phase, we hope to gain insights into the progenitor systems and determine the accuracy of early-time subclassifications of these objects. Several of our supernovae exhibit double-peaked spectral lines, which may indicate a violent merger progenitor system. We also remark on interesting spectral features and compare our sample of objects to other well-observed Type Ia supernovae presented in other papers.

  13. The circumplanetary nebular environment: A possible source region for chondrules

    NASA Technical Reports Server (NTRS)

    Sanders, I. S.

    1994-01-01

    Hypotheses for the origin of chondrules fall into two broad groups: nebular and planetary. Arguments against the latter have prevailed in recent years such that, by default, the less testable nebular setting for chondrule formation is now generally favored. However, the recognition in ordinary chondrites of igneous clasts that probably formed on, or in, small planetoids hints that some parent bodies were still accreting after others had evolved magmatically and lost material to space, presumably by impact. If melting of planetoids can predate accretion, could the same early melting even be related to chondrule production? My affirmative response to this interesting question is expanded here in a chondrule-forming scenario, which incorporates both planetary and nebular features.

  14. Effect of Laser Power and Scan Speed on Melt Pool Characteristics of Commercially Pure Titanium (CP-Ti)

    NASA Astrophysics Data System (ADS)

    Kusuma, Chandrakanth; Ahmed, Sazzad H.; Mian, Ahsan; Srinivasan, Raghavan

    2017-07-01

    Selective laser melting (SLM) is an additive manufacturing technique that creates complex parts by selectively melting metal powder layer-by-layer using a laser. In SLM, the process parameters decide the quality of the fabricated component. In this study, single beads of commercially pure titanium (CP-Ti) were melted on a substrate of the same material using an in-house built SLM machine. Multiple combinations of laser power and scan speed were used for single bead fabrication, while the laser beam diameter and powder layer thickness were kept constant. This experimental study investigated the influence of laser power, scan speed, and laser energy density on the melt pool formation, surface morphology, geometry (width and height), and hardness of solidified beads. In addition, the observed unfavorable effect such as inconsistency in melt pool width formation is discussed. The results show that the quality, geometry, and hardness of solidified melt pool are significantly affected by laser power, scanning speed, and laser energy density.

  15. Chondritic Meteorites: Nebular and Parent-Body Formation Processes

    NASA Technical Reports Server (NTRS)

    Rubin, Alan E.; Lindstrom, David (Technical Monitor)

    2002-01-01

    It is important to identify features in chondrites that formed as a result of parent-body modification in order to disentangle nebular and asteroidal processes. However, this task is difficult because unmetamorphosed chondritic meteorites are mixtures of diverse components including various types of chondrules, chondrule fragments, refractory and mafic inclusions, metal-sulfide grains and fine-grained matrix material. Shocked chondrites can contain melt pockets, silicate-darkened material, metal veins, silicate melt veins, and impact-melt-rock clasts. This grant paid for several studies that went far in helping to distinguish primitive nebular features from those produced during asteroidal modification processes.

  16. Igneous rock from Severnyi Kolchim (H3) chondrite: Nebular origin

    NASA Technical Reports Server (NTRS)

    Nazarov, M. A.; Brandstaetter, F.; Kurat, G.

    1993-01-01

    The discovery of lithic fragments with compositions and textures similar to igneous differentiates in unequilibrated ordinary chondrites (UOC's) and carbonaceous chondrites (CC's) has been interpreted as to suggest that planetary bodies existed before chondrites were formed. As a consequence, chondrites (except, perhaps CI chondrites) cannot be considered primitive assemblages of unprocessed nebular matter. We report about our study of an igneous clast from the Severnyi Kolchim (H3) chondrite. The results of the study are incompatible with an igneous origin of the clast but are in favor of a nebular origin similar to that of chondrules.

  17. Pioneer Nebular Theorists from Zanstra to Seaton: and Beyond

    NASA Astrophysics Data System (ADS)

    Osterbrock, D. E.

    2002-02-01

    A brief history of theoretical nebular astrophysics, particularly in USA, is presented. The importance of observational knowledge of objects that actually exist is emphasized as a prerequisite for most theories. Herman Zanstra and Ira Bowen were the two most important theorists in opening the field. Donald Menzel and his students, especially James Baker, Leo Goldberg, and Lawrence Aller, were quite important in the further development of it. Henry Norris Russell started nebular astrophysics rolling, and several other later theorists, including Bengt Strömgren, Lyman Spitzer, Iosif Shklovsky and Michael Seaton, also made important contributions to it.

  18. Nebular Continuum and Line Emission in Stellar Population Synthesis Models

    NASA Astrophysics Data System (ADS)

    Byler, Nell; Dalcanton, Julianne J.; Conroy, Charlie; Johnson, Benjamin D.

    2017-05-01

    Accounting for nebular emission when modeling galaxy spectral energy distributions (SEDs) is important, as both line and continuum emissions can contribute significantly to the total observed flux. In this work, we present a new nebular emission model integrated within the Flexible Stellar Population Synthesis code that computes the line and continuum emission for complex stellar populations using the photoionization code Cloudy. The self-consistent coupling of the nebular emission to the matched ionizing spectrum produces emission line intensities that correctly scale with the stellar population as a function of age and metallicity. This more complete model of galaxy SEDs will improve estimates of global gas properties derived with diagnostic diagrams, star formation rates based on Hα, and physical properties derived from broadband photometry. Our models agree well with results from other photoionization models and are able to reproduce observed emission from H ii regions and star-forming galaxies. Our models show improved agreement with the observed H ii regions in the Ne iii/O ii plane and show satisfactory agreement with He ii emission from z = 2 galaxies, when including rotating stellar models. Models including post-asymptotic giant branch stars are able to reproduce line ratios consistent with low-ionization emission regions. The models are integrated into current versions of FSPS and include self-consistent nebular emission predictions for MIST and Padova+Geneva evolutionary tracks.

  19. Versatile nebular insect-eye fabry-perot spectrograph.

    PubMed

    Meaburn, J

    1975-02-01

    The design and performance of an insect-eye F.P. spectrograph used on the 249-cm Isaac Newton telescope, which can also be converted into a nebular filter camera, is presented. This device has several novel features, including a pressure-controlled optically contacted etalon and an image tube as a detector.

  20. ALIEN: A Software Package for Nebular Spectral Analysis

    NASA Astrophysics Data System (ADS)

    Cook, R.; Vázquez, R.

    2002-02-01

    ALIEN is a software designed to analyze low dispersion nebular spectra. Dereddening and calculation of physical conditions and ionic abundances by number are included. This software was written in the C language under Linux, the GUI has been developed using XForms (Kubat 1996) to provide a user friendly environment.

  1. Systematic analysis of the timing and power impact of pure lines and cuts routing for multiple patterning

    NASA Astrophysics Data System (ADS)

    Vashishtha, Vinay; Masand, Lovish; Dosi, Ankita; Ramamurthy, Chandarasekaran; Clark, Lawrence T.

    2017-03-01

    Line and cut based patterning for BEOL layers is an attractive solution to address the block mask patterning challenges related to self-aligned double patterning. It also enables integrated fill, with fill as an artifact of unused metal routes following lines and cuts patterning. Traditional post-layout fill involves inserting metal at large distances to limit design impact, but is less effective at alleviating metal thickness variation due to density effects. While integrated fill reduces metal thickness variation, it has a negative impact on capacitance, delay and power dissipation. This work studies the impact of pure lines/cuts integrated fill on design performance metrics using a predictive 7 nm PDK. Two fully implemented auto-place and routed (APR) designs are considered for the experiments, one small and one large. Our comparison is from no fill to integrated fill, assuming conventional fill would not impact timing. The impact of integrated fill on capacitance and overall timing is evaluated using Calibre PEX and PrimeTime. We show these results are in line with simple "back of the envelope" estimates and simple models and are very significant for large designs.

  2. Telling Liers From Liners: The Nature Of The Nebular Emission Of Early-type Galaxies

    NASA Astrophysics Data System (ADS)

    Sarzi, Marc; Oh, K.; Yi, S.; Shields, J. C.; Schawinski, K.

    2011-01-01

    It is now well documented that early-type galaxies (ETGs) are not just passive stellar systems since they often exhibit a relatively weak degree of nebular activity. Such ionized-gas emission is generally characterized by the presence of low-ionization lines, as found in low-ionization nuclear emission-line regions or LINERs. Recent SAURON integral-field spectroscopic (IFS) observations have shown that the nebular activity of ETGs is always extended and thus requires another source of ionization than a central AGN, most likely old UV-bright stars. In fact, the nuclear LINER emission of ETGs very rarely dominates the integrated nebular spectrum of these systems. This means that in large-scale surveys such as the Sloan Digital Sky Survey (SDSS) where the spectra encompass most of the light from the target galaxies, the LINER-like emission observed in distant ETGs is actually dominated by extended low-ionization emission regions, or LIERs. Such LIERs can have only modest values for the equivalent width of strong emission lines such as [OIII]5007, whereas only AGNs can power the strongest [OIII] emission of true LINERs. This finding provides an excellent opportunity to further study the nature of such an extended emission, and in particular its source of ionization. The SDSS data offer indeed a much larger array of emission lines that the SAURON IFS data, if a sufficient number of spectra is stacked to bring out the signal of the weak low-ionisation lines. Using a complete catalogue of SDSS DR7 spectra of morphologically selected ETGs we will present and examine the salient features of the best spectral templates for both the central LINER and extended LIER emission of ETGs.

  3. Chondrule Formation: Nebular Gas Confinement of Impact Splashes

    NASA Astrophysics Data System (ADS)

    Dullemond, Cornelis Petrus; Johansen, Anders

    2013-07-01

    We show that the impact debris from a high-speed collision between two planetesimals during the first few million years would sweep up the nebular gas as a snow plow, leading to deceleration and compression of the debris into a thin shell. This shell breaks up into dense bullets through the Rayleigh-Taylor instability. As a result of the compression by the gas, these bullets will have super-Roche densities and thus will gravitationally collapse to form new planetesimals. Chondrules that may have formed from impact melting would thus rapidly be reaccreted into planetesimals. These dense environments are ideal for forming compound chondrules. The hydrodynamic interaction with the nebular gas could lead to mixing between the newly formed chondrules and surviving pre-impact material. Volatiles can be exchanged between these components in the dense bullets, allowing for chemical complementarity. We believe that this scenario may have some advantages over earlier impact scenarios for chondrule formation.

  4. V. M. Slipher and the Development of the Nebular Spectrograph

    NASA Astrophysics Data System (ADS)

    Thompson, L. A.

    2013-04-01

    Vesto Melvin Slipher was the first astronomer to clearly define the factors that determine the “speed” of a nebular spectrograph. This brief historical summary recounts the way these ideas developed and how Slipher's early work on galaxy Doppler shifts was so quickly extended in the 1930s when Milton Humason and Edwin Hubble at Mt. Wilson Observatory began to push the velocity-distance relationship to such a depth that no one could doubt its cosmological significance.

  5. Quantifying the impact of AGN and nebular emission on stellar population properties with REBETIKO

    NASA Astrophysics Data System (ADS)

    Cardoso, L. S. M.; Gomes, J. M.; Papaderos, P.

    2016-06-01

    Spectral synthesis enables the reconstruction of the star formation and chemical evolution histories (SFH & CEH) of a galaxy that are encoded in its spectral energy distribution (SED). Most state-of-the-art population synthesis codes however consider only purely stellar emission and are hence inadequate for modelling studies of galaxies where non-stellar emission components contribute significantly to the SED. This work combines evolutionary and population synthesis techniques to quantify the impact of active galactic nucleus (AGN) and nebular emission on the determination of the stellar population properties in galaxies. We have developed an evolutionary synthesis code called REBETIKO - Reckoning galaxy Emission By means of Evolutionary Tasks with Input Key Observables - to compute and study the time evolution of the SED of AGN-hosts and starburst galaxies. Our code takes into account the main ingredients of a galaxy's SED (e.g. non-thermal emission and/or nebular continuum and lines) for various commonly used parameterizations of the SFH, such as instantaneous burst, constant, exponentially decreasing, and gradually increasing peaking at a redshift between 1-10. Synthetic SEDs computed with REBETIKO have been subsequently fitted with the STARLIGHT population synthesis code (PSC) which can be regarded as representative for currently available state-of-the-art (i.e. purely stellar) PSCs. The objective is to study the impact of non-stellar SED components on the recovery of the true total stellar mass M_{star} and SFH of a galaxy, as well as other evolutionary properties, such as CEH and light- and mass-weighted mean stellar age and metallicity. We find that purely stellar fits in galaxies with a strong non-stellar continuum (e.g. Seyfert and/or starburst galaxies) can for instance overestimate M_{star} by up to 3 orders of magnitude, while the mean stellar age and metallicity can deviate from their true values up to 2 and 4 dex, respectively. These results imply

  6. The Nebular Hypothesis - A False Paradigm Misleading Scientists

    NASA Astrophysics Data System (ADS)

    Myers, L. S.

    2005-05-01

    Science has reached a turning point in history after being misled for 250 years by Immanuel Kant's nebular hypothesis, the most fundamental assumption in science. The nebular hypothesis assumes all nine planets were created 4.5 billion years ago (Ga) as molten bodies that cooled with the same size and chemical composition they have today. Reevaluation of the nebular hypothesis proves it has been wrong since its inception. The proof has lain in plain sight for centuries-coal beds that could not have existed at the assumed time of creation because they formed on Earth's surface after creation of the planet when forests and swamps were exposed to solar energy. The coal beds were subsequently buried under overburden accreted in later millennia, steadily increasing Earth's mass and diameter. The coal beds and layers of overburden are proof Earth was not created 4.5 Ga but is growing and expanding by accretion of extraterrestrial mass and core expansion-a process termed "Accreation" (creation by accretion). Each process accelerates over time, but internal expansion exceeds the rate of external accretion. Because the nebular hypothesis is erroneous researchers assumed Earth's diameter never changes, and, faced with the possibility the Earth might be expanding after the Atlantic basin was discovered to be widening, this assumption led to the unworkable concept of subduction to maintain a constant diameter Earth. Subduction will prove to be one of the greatest errors in the history of science. Nullification of the nebular hypothesis also nullifies subduction and rejuvenates Carey's earth expansion theory. Accreation provides Carey's missing energy source and mechanism of expansion. Expansion is proved by morphologic evidence today's continents were once a single planetary landmass on a smaller Earth when today's oceans, covering 70% of the planet, did not exist 200-250 Ma. Despite hundreds of tons of meteorites and dust known to accrete daily, its cumulative effect has been

  7. Collision strengths for nebular [O III] optical and infrared lines

    NASA Astrophysics Data System (ADS)

    Storey, P. J.; Sochi, Taha; Badnell, N. R.

    2014-07-01

    We present electron collision strengths and their thermally averaged values for the nebular forbidden lines of the astronomically abundant doubly ionized oxygen ion, O2+, in an intermediate coupling scheme using the Breit-Pauli relativistic terms as implemented in an R-matrix atomic scattering code. We use several atomic targets for the R-matrix scattering calculations including one with 72 atomic terms. We also compare with new results obtained using the intermediate coupling frame transformation method. We find spectroscopically significant differences against a recent Breit-Pauli calculation for the excitation of the [O III] λ4363 transition but confirm the results of earlier calculations.

  8. Investigation of the Changes in the Power Distribution in Resting-State Brain Networks Associated with Pure Conduct Disorder.

    PubMed

    Zhang, Jiang; Zhou, Jiansong; Lu, Fengmei; Chen, Liangyin; Huang, Yunzhi; Chen, Huafu; Xiang, Yutao; Yang, Gang; Yuan, Zhen

    2017-07-17

    Conduct disorder (CD) is a psychiatric disorder in children and adolescence. To investigate changes in the power distribution in brain networks between CD and typically developing (TD) groups, resting-state functional magnetic resonance imaging (rsfMRI) data of thirty-six subjects were first recorded, and then the data were preprocessed using DPARSF and SPM8. Meanwhile, the power of the blood oxygenation level-dependent (BOLD) signals of ninety brain regions was acquired using the integral of the Welch power spectral density (PSD). Additionally, the powers of the brain regions that reached significance (p < 0.05) were extracted using the bootstrap statistics, in which the standardized z-scores of the powers were used as a reference. The results of the analysis of the changes in power exhibited that there were significant power differences in some pairs of brain regions between the CD and TD groups, indicating a change in the power distribution. In addition, the results also suggest that the total power consumption of brain networks in CD patients is less than that observed in the TD group. Consequently, the study provided a paradigm for establishing quantifiable indicators via the power spectrum approach for the comparison and analysis of the BOLD signal power between CD patients and healthy controls.

  9. Lightning and Mass Independent Oxygen Isotopic Fractionation in Nebular Silicates

    NASA Technical Reports Server (NTRS)

    Nuth, Joseph A.

    2009-01-01

    Lightning has long been postulated as the agent of Chondru|e formation in the solar nebula, but it may have an additional role to play as well. Lightning bolts of almost any scale will both vaporize dust and liberate oxygen atoms that will then interact with both nebular gases as well as the refractory silicate vapor as it re-condenses. Such processes should result in the addition of the heavy oxygen isotopes to the growing silicate grains while the light oxygen-16 becomes part of the gas phase water. This process will proceed to some extent throughout the history of any turbulent nebula and will result in the gradual increase of O-16 in the gas phase and in a much larger relative increase in the O-17 and O-18 content of the nebular dust. Laboratory experiments have demonstrated the production of such "heavy oxygen enriched", non-mass-dependently-fractionated dust grains in a high voltage discharge in a hydrogen rich gas containing small quantities of silane, pentacarbonyl iron and oxygen.

  10. Volatile elements in chondrites - Metamorphism or nebular fractionation

    NASA Technical Reports Server (NTRS)

    Takahashi, H.; Gros, J.; Higuchi, H.; Morgan, J. W.; Anders, E.

    1978-01-01

    Three of the most highly metamorphosed meteorites of their respective classes, Shaw (LL7), Karoonda (C5), and Coolidge (C4), were analyzed by radiochemical neutron activation analysis for Ag, Au, Bi, Br, Cd, Cs, Ge, In, Ir, Ni, Os, Pd, Rb, Re, Sb, Se, Te, Tl, U, and Zn. Comparison with data by Lipschutz and coworkers (1977) on artificially heated primitive meteorites shows that the natural metamorphism of meteorites cannot have taken place in a system open to volatiles. Shaw, metamorphosed at 1300 C for more than 1 million yr, is less depleted in In, Bi, Ag, Te, Zn, and Tl than Krymka heated at 1000 C for 1 week. Karoonda, metamorphosed at 600 C for many millennia, is less depleted in Bi and Tl than Allende heated at 600 C for 1 week. Data on primordial noble gases also show that the volatile-element patterns of ordinary and carbonaceous chondrites were established by nebular condensation and changed little, if at all, during metamorphism. For enstatite chondrites, the evidence is still incomplete but seems to favor a nebular origin of the volatile pattern.

  11. Petrologic evolution of CM chondrites: The difficulty of discriminating between nebular and parent-body effects

    NASA Astrophysics Data System (ADS)

    Kerridge, J. F.; McSween, H. Y., Jr.; Bunch, T. E.

    1994-07-01

    We wish to draw attention to a major controversy that has arisen in the area of CM-chondrite petrology. The problem is important because its resolution will have profound implications for ideas concerning nebular dynamics, gas-solid interactions in the nebula, and accretionary processes in the nebula, among other issues. On the one hand, cogent arguments have been presented that 'accretionary dust mantles,' were formed in the solar nebula prior to accretion of the CM parent asteroid(s). On the other hand, no-less-powerful arguments have been advanced that a significant fraction of the CM lithology is secondary, produced by aqueous alteration in the near-surface regions of an asteroid-sized object. Because most, if not all, CM chondrites are breccias, these two views could coexist harmoniously, were it not for the fact that some of the coarse-grained lithologies surrounded by 'accretion dust mantles' are themselves of apparently secondary origin. Such an observation must clearly force a reassessment of one or both of the present schools of thought. Our objective here is to stimulate such a reassessment. Four possible resolutions of this conflict may be postulated. First, perhaps nature found a way of permitting such secondary alteration to take place in the nebula. Second, maybe dust mantles could form in a regolith, rather than a nebular, environment. Third, it is possible that dust mantles around secondary lithologies are different from those around primary lithologies. Finally, perhaps formation of CM chondrites involved a more complex sequence of events than visualized so far, so that some apparently 'primary' processes postdated certain 'secondary' processes.

  12. A dual-mode operation overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic mode output

    SciTech Connect

    Bai, Zhen; Zhang, Jun Zhong, Huihuang

    2016-04-15

    An overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic (TEM) mode output is designed and presented, by using a kind of coaxial slow wave structure (SWS) with large transversal dimension and small distance between inner and outer conductors. The generator works in dual-mode operation mechanism. The electron beam synchronously interacts with 7π/8 mode of quasi-TEM, at the meanwhile exchanges energy with 3π/8 mode of TM{sub 01}. The existence of TM{sub 01} mode, which is traveling wave, not only increases the beam-wave interaction efficiency but also improves the extraction efficiency. The large transversal dimension of coaxial SWS makes its power capacity higher than that of other reported millimeter-wave devices and the small distance between inner and outer conductors allows only two azimuthally symmetric modes to coexist. The converter after the SWS guarantees the mode purity of output power. Particle-in-cell simulation shows that when the diode voltage is 400 kV and beam current is 3.8 kA, the generation of microwave at 32.26 GHz with an output power of 611 MW and a conversion efficiency of 40% is obtained. The power percentage carried by TEM mode reaches 99.7% in the output power.

  13. Supernova 1987 A - The nebular loops and 'Napoleon's Hat'

    NASA Astrophysics Data System (ADS)

    Wang, L.; Wampler, E. J.

    1992-08-01

    We discuss observations of the circumstellar environment of SN 1987A that were obtained between August 1989 and January 1992 at ESO's New Technology Telescope. We find that the angular dimensions of the two nebular loops (Wampler et al., 1990) have not changed during this period. Therefore these loops are confined to a small region. The expansion velocity of the loops is less than about 40 km/s if the loops expanded with a uniform velocity from a common origin. This structure and velocity is hard to reproduce with existing wind interaction models. Our observations further suggest that the Napoleon's Hat nebula does not originate from the general background LMC dust, but from a bow shock dust whose origins are closely related to the stellar winds from the progenitor star of SN 1987A.

  14. Chondritic Meteorites: Nebular and Parent-Body Formation Process

    NASA Technical Reports Server (NTRS)

    Rubin, Alan E.

    1997-01-01

    Chondritic meteorites are the products of condensation, agglomeration and accretion of material in the solar nebula; these objects are the best sources of information regarding processes occurring during the early history of the solar system. We obtain large amounts of high-quality chemical and petrographic data and use them to infer chemical fractionation processes that occurred in the solar nebula and on meteorite parent bodies during thermal metamorphism, shock metamorphism and aqueous alteration. We compare diverse groups of chondrites and model their different properties in terms of processes that differed at different nebular locations or on different parent-bodies. In order to expand our set of geochemically important elements (particularly Si, C, P and S) and to distinguish the different oxidation states of Fe, Greg Kallemeyn spent three months (1 Sept. - 30 Nov. 1995) at the Smithsonian Institution to learn Eugene Jarosewich's wet chemical techniques. Key specimens from the recently established CK, CR and R chondrite groups were analyzed.

  15. The impact of atomic data selection on nebular abundance determinations

    NASA Astrophysics Data System (ADS)

    Juan de Dios, Leticia; Rodríguez, Mónica

    2017-07-01

    Atomic data are an important source of systematic uncertainty in our determinations of nebular chemical abundances. However, we do not have good estimates of these uncertainties since it is very difficult to assess the accuracy of the atomic data involved in the calculations. We explore here the size of these uncertainties by using 52 different sets of transition probabilities and collision strengths, and all their possible combinations, to calculate the physical conditions and the total abundances of O, N, S, Ne, Cl and Ar for a sample of planetary nebulae and H ii regions. We find that atomic data variations introduce differences in the derived abundance ratios as low as 0.1-0.2 dex at low density, but that reach or surpass 0.6-0.8 dex at densities above 104 cm-3 in several abundance ratios, like O/H and N/O. Removing from the 52 data sets the four data sets that introduce the largest differences, the total uncertainties are reduced, but high-density objects still reach uncertainty factors of four for their values of O/H and N/O. We identify the atomic data that introduce most of the uncertainty, which involves the ions used to determine density, namely, the transition probabilities of the S+, O+, Cl++ and Ar+3 density diagnostic lines, and the collision strengths of Ar+3. Improved calculations of these data will be needed in order to derive more reliable values of chemical abundances in high-density nebulae. In the meantime, our results can be used to estimate the uncertainties introduced by atomic data in nebular abundance determinations.

  16. Non-equilibrium effects on the chemistry of nebular condensates - Implications for the planets and asteroids

    NASA Technical Reports Server (NTRS)

    Blander, M.

    1979-01-01

    Kinetic effects, for example nucleation constraints and slow reactions, should have been important in nebular condensation. Consideration of these effects leads to the prediction of pressure-dependent compositions and physical properties of nebular condensates which is consistent with (1) the differences between different classes of chondritic meteorites, (2) some of the differences between planets, and (3) the presence of oxidized iron on the moon and in the eucrite parent body (presumably an asteroid) despite the low abundance of volatiles. Diffusion effects appear to be important for understanding oxygen isotope anomalies in refractory inclusions in Allende. The consideration of kinetic effects leads to more information concerning nebular processes than if equilibrium is assumed.

  17. Pure colloidal metal and ceramic nanoparticles from high-power picosecond laser ablation in water and acetone.

    PubMed

    Bärsch, Niko; Jakobi, Jurij; Weiler, Sascha; Barcikowski, Stephan

    2009-11-04

    The generation of colloids by laser ablation of solids in a liquid offers a nearly unlimited material variety and a high purity as no chemical precursors are required. The use of novel high-power ultra-short-pulsed laser systems significantly increases the production rates even in inflammable organic solvents. By applying an average laser power of 50 W and pulse durations below 10 ps, up to 5 mg min(-1) of nanoparticles have been generated directly in acetone, marking a breakthrough in productivity of ultra-short-pulsed laser ablation in liquids. The produced colloids remain stable for more than six months. In the case of yttria-stabilized zirconia ceramic, the nanoparticles retain the tetragonal crystal structure of the ablated target. Laser beam self-focusing plays an important role, as a beam radius change of 2% on the liquid surface can lead to a decrease of nanoparticle production rates of 90% if the target position is not re-adjusted.

  18. NEBULAR SPECTRA AND EXPLOSION ASYMMETRY OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Maeda, K.; Nomoto, K.; Taubenberger, S.; Mazzali, P.A.; Sollerman, J.; Leloudas, G.; Motohara, K.

    2010-01-10

    The spectral signatures of asymmetry in Type Ia Supernova (SN Ia) explosions are investigated, using a sample of late-time nebular spectra. First, a kinematical model is constructed for SN Ia 2003hv, which can account for the main features in its optical, Near-Infrared (NIR), and Mid-Infrared (Mid-IR) late-time spectra. It is found that an asymmetric off-center model can explain the observed characteristics of SN 2003hv. This model includes a relatively high-density, Fe-rich region which displays a large velocity off-set, and a relatively low density, extended {sup 56}Ni-rich region which is more spherically distributed. The high-density region consists of the inner stable Fe-Ni region and outer {sup 56}Ni-rich region. Such a distribution may be the result of a delayed-detonation explosion, in which the first deflagration produces the global asymmetry in the innermost ejecta, while the subsequent detonation can lead to the bulk spherical symmetry. This configuration, if viewed from the direction of the off-set, can consistently explain the blueshift in some of the emission lines and virtually no observed shift in other lines in SN 2003hv. For this model, we then explore the effects of different viewing angles and the implications for SNe Ia in general. The model predicts that a variation of the central wavelength, depending on the viewing angle, should be seen in some lines (e.g., [Ni II] lambda7378), while the strongest lines (e.g., [Fe III] blend at approx4700 A) will not show this effect. By examining optical nebular spectra of 12 SNe Ia, we have found that such a variation indeed exists. We suggest that the global asymmetry in the innermost ejecta, as likely imprint of the deflagration flame propagation, is a generic feature of SNe Ia. It is also shown that various forbidden lines in the NIR and Mid-IR regimes provide strong diagnostics to further constrain the explosion geometry and thus the explosion mechanism.

  19. Asteroids and Comets — Did the Diversify of Nebular Solids Decline with Distance from the Sun?

    NASA Astrophysics Data System (ADS)

    Brownlee, D. E.; Joswiak, D. J.

    2015-07-01

    The Mn contents of ferrous olivine grains in a cluster IDP of probable cometary origin match what is seen in comet Wild 2 olivines. This finding is consistent with suggestions that most comets contain similar averaged samplings of nebular solids.

  20. Radiation Hydrodynamics Meets Nebular Evolution at the Hubble Space Telescope

    NASA Astrophysics Data System (ADS)

    Balick, Bruce

    1997-04-01

    The evolution of gaseous nebular hydrodynamics in astrophysics interests everyone studying star formation, stellar winds and ejecta, shocks assoicated with supernovae and other explosive events, outflows from black holes and neutron stars, and active galactic nuclei. However, even the closest nebulae cannot be studied on size scales of a mean free path, typically 10^15.5 cm, from the ground. Entire generations of models have been computed ``in the dark'' without recourse to observational feedback and evaluation. [0.1cm] The Hubble Space Telescope with its corrected optics is providing exciting new images which are helping to verify many of the model computations, sharpening others, and overturning all sorts of expectations. In this talk I shall describe the immense changes occurring in radiation hydrodynamics through a brief ``tour'' of HST images of planetary nebulae (like these and these) - a particulary bright, nearby, simple, and well-studied class of objects formed as dying stars shed and then wind-sculpt and photoionize their former envelopes into nebulae of strikingly complex symmetries and morphology. A review of the physical processes believed to affect the state and flow variables of these astrophyscial nebulae will also be introduced.

  1. Recombination coefficients for O ii lines in nebular conditions

    NASA Astrophysics Data System (ADS)

    Storey, P. J.; Sochi, Taha; Bastin, Robert

    2017-09-01

    We present the results of a calculation of recombination coefficients for O2++ e- using an intermediate coupling treatment that fully accounts for the dependence of the distribution of population among the ground levels of O2+ on electron density and temperature. The calculation is extended down to low electron temperatures, where dielectronic recombination arising from Rydberg states converging on the O2+ ground levels is an important process. The data that consist of emission coefficients for 8889 recombination lines and recombination coefficients for the ground and metastable states of O+ are in Cases A, B and C, and are organized as a function of the electron temperature and number density, as well as wavelength. An interactive fortran 77 data server is also provided as an accessory for mining the line emission coefficients and obtaining Lagrange interpolated values for any choice of the two variables between the explicitly provided values for any set of wavelengths. Some illustrations of the application of the new data to nebular observations are also provided.

  2. No nebular magnetization in the Allende CV carbonaceous chondrite

    NASA Astrophysics Data System (ADS)

    Fu, R. R.; Lima, E. A.; Weiss, B. P.

    2014-10-01

    Magnetic fields in the solar nebula may have played a central role in mass and angular momentum transport in the protosolar disk and facilitated the accretion of the first planetesimals. Thought to be key evidence for this hypothesis is the high unblocking-temperature, randomly oriented magnetization in chondrules in the Allende CV carbonaceous chondrite. However, it has recently been realized that most of the ferromagnetic minerals in Allende are products of secondary processes on the parent planetesimal. Here we reevaluate the pre-accretional magnetism hypothesis for Allende using new paleomagnetic analyses of chondrules including the first measurements of mutually oriented subsamples from within individual chondrules. We confirm that Allende chondrules carry a high-temperature component of magnetization that is randomly oriented among chondrules. However, we find that subsamples of individual chondrules are also non-unidirectionally magnetized. Therefore, the high-temperature magnetization in Allende chondrules is not a record of nebular magnetic fields and is instead best explained by remagnetization during metasomatism in a <8 μT magnetic field. This low field intensity suggests that any core dynamo on the CV parent body decayed before the end of metasomatism, likely <40 My after the formation of calcium aluminum-rich inclusions (CAIs). Despite widespread practice, the magnetization in Allende should not be used to constrain magnetic fields in the protosolar nebula.

  3. THE DECELERATION OF NEBULAR SHELLS IN EVOLVED PLANETARY NEBULAE

    SciTech Connect

    Pereyra, Margarita; Richer, Michael G.; Lopez, Jose Alberto E-mail: richer@astrosen.unam.mx

    2013-07-10

    We have selected a group of 100 evolved planetary nebulae (PNe) and study their kinematics based upon spatially-resolved, long-slit, echelle spectroscopy. The data have been drawn from the San Pedro Martir Kinematic Catalogue of PNe. The aim is to characterize in detail the global kinematics of PNe at advanced stages of evolution with the largest sample of homogenous data used to date for this purpose. The results reveal two groups that share kinematics, morphology, and photo-ionization characteristics of the nebular shell and central star luminosities at the different late stages under study. The typical flow velocities we measure are usually larger than seen in earlier evolutionary stages, with the largest velocities occurring in objects with very weak or absent [N II] {lambda}6584 line emission, by all indications the least evolved objects in our sample. The most evolved objects expand more slowly. This apparent deceleration during the final stage of PNe evolution is predicted by hydrodynamical models, but other explanations are also possible. These results provide a template for comparison with the predictions of theoretical models.

  4. Nebular emission from AGN in the ultraviolet/optical: diagnostics of the ionizing source and gas properties

    NASA Astrophysics Data System (ADS)

    Feltre, A.

    2016-08-01

    Spectroscopic studies of active galactic nuclei (AGN) are powerful means of probing the physical properties of the ionized gas within them. In particular, forthcoming facilities such as JWST and the E-ELT, will provide rest-frame ultraviolet and optical spectra of the very distant AGN. To lay the groundwork for the interpretation of these revolutionary datasets, we have recently computed new photoionization models of the narrow-line emitting regions (NLR) of AGN and combined them with similar models of the nebular emission from star-forming galaxies. In this talk, I will first describe how new ultraviolet and standard optical spectral diagnostics allow one to distinguish between nuclear activity and star formation. I will then explain how predictions of AGN nebular emission can be best used to understand the physical properties of the AGN NLR gas. In particular, I will present recent results from a study on one of the most comprehensive set of optical spectra (from VIMOS/VLT) sampling the rest-frame ultraviolet range of ~90 type 2 AGN (1.5 < z < 3), drawn from the z-COSMOS deep survey. To conclude, I will show how the implementation of AGN photoionization calculations in an innovative Bayesian fitting code can help us best interpret current, and future, spectro-photometric data on active galaxies.

  5. Nebular emission and the Lyman continuum photon escape fraction in CALIFA early-type galaxies

    NASA Astrophysics Data System (ADS)

    Papaderos, P.; Gomes, J. M.; Vílchez, J. M.; Kehrig, C.; Lehnert, M. D.; Ziegler, B.; Sánchez, S. F.; Husemann, B.; Monreal-Ibero, A.; García-Benito, R.; Bland-Hawthorn, J.; Cortijo-Ferrero, C.; de Lorenzo-Cáceres, A.; del Olmo, A.; Falcón-Barroso, J.; Galbany, L.; Iglesias-Páramo, J.; López-Sánchez, Á. R.; Marquez, I.; Mollá, M.; Mast, D.; van de Ven, G.; Wisotzki, L.

    2013-07-01

    We use deep integral field spectroscopy data from the CALIFA survey to study the warm interstellar medium (wim) over the entire extent and optical spectral range of 32 nearby early-type galaxies (ETGs). We find that faint nebular emission is extended in all cases, and its surface brightness decreases roughly as ∝ r-α. The large standard deviation in the derived α (1.09 ± 0.67) argues against a universal power-law index for the radial drop-off of nebular emission in ETGs. Judging from the properties of their extranuclear component, our sample ETGs span a broad, continuous sequence with respect to their α, Hα equivalent width (EW) and Lyman continuum (Lyc) photon leakage fraction (plf). We propose a tentative subdivision into two groups: Type i ETGs are characterized by rather steep Hα profiles (α ≃ 1.4), comparatively large (≳1 Å), nearly radially constant EWs, and plf ≃ 0. Photoionization by post-AGB stars appears to be the main driver of extended nebular emission in these systems, with nonthermal sources being potentially important only in their nuclei. Typical properties of type II ETGs are shallower Hα profiles (α ≃ 0.8), very low (≲0.5 Å) EWs with positive radial gradients, and a mean plf ≳ 0.7, rising to ≳0.9 in their centers. Such properties point to a low, and inwardly decreasing wim density and/or volume filling factor. We argue that, because of extensive Lyc photon leakage, emission-line luminosities and EWs are reduced in type II ETG nuclei by at least one order of magnitude. Consequently, the line weakness of these ETGs is by itself no compelling evidence for their containing merely "weak"(sub-Eddington accreting) active galactic nuclei (AGN). In fact, Lyc photon escape, which has heretofore not been considered, may constitute a key element in understanding why many ETGs with prominent signatures of AGN activity in radio continuum and/or X-ray wavelengths show only faint emission lines and weak signatures of AGN activity in

  6. Comparative 4-E analysis of a bottoming pure NH3 and NH3-H2O mixture based power cycle for condenser waste heat recovery

    NASA Astrophysics Data System (ADS)

    Khankari, Goutam; Karmakar, Sujit

    2017-06-01

    This paper proposes a comparative performance analysis based on 4-E (Energy, Exergy, Environment, and Economic) of a bottoming pure Ammonia (NH3) based Organic Rankine Cycle (ORC) and Ammonia-water (NH3-H2O) based Kalina Cycle System 11(KCS 11) for additional power generation through condenser waste heat recovery integrated with a conventional 500MWe Subcritical coal-fired thermal power plant. A typical high-ash Indian coal is used for the analysis. The flow-sheet computer programme `Cycle Tempo' is used to simulate both the cycles for thermodynamic performance analysis at different plant operating conditions. Thermodynamic analysis is done by varying different NH3 mass fraction in KCS11 and at different turbine inlet pressure in both ORC and KCS11. Results show that the optimum operating pressure of ORC and KCS11 with NH3 mass fraction of 0.90 are about 15 bar and 11.70 bar, respectively and more than 14 bar of operating pressure, the plant performance of ORC integrated power plant is higher than the KCS11 integrated power plant and the result is observed reverse below this pressure. The energy and exergy efficiencies of ORC cycle are higher than the KCS11 by about 0.903 % point and 16.605 % points, respectively under similar saturation vapour temperature at turbine inlet for both the cycles. Similarly, plant energy and exergy efficiencies of ORC based combined cycle power plant are increased by 0.460 % point and 0.420 % point, respectively over KCS11 based combined cycle power plant. Moreover, the reduction of CO2 emission in ORC based combined cycle is about 3.23 t/hr which is about 1.5 times higher than the KCS11 based combined cycle power plant. Exergy destruction of the evaporator in ORC decreases with increase in operating pressure due to decrease in temperature difference of heat exchanging fluids. Exergy destruction rate in the evaporator of ORC is higher than KCS11 when the operating pressure of ORC reduces below 14 bar. This happens due to variable

  7. History of Nebular Processing Traced by Silicate Stardust in IDPS

    NASA Technical Reports Server (NTRS)

    Messenger, Scott R.; Keller, L. P.; Nakamura-Messenger, K.

    2010-01-01

    Chondritic porous interplanetary dust particles (CP-IDPs) may be the best preserved remnants of primordial solar system materials, in part because they were not affected by parent body hydrothermal alteration. Their primitive characteristics include fine grained, unequilibrated, anhydrous mineralogy, enrichment in volatile elements, and abundant molecular cloud material and silicate stardust. However, while the majority of CP-IDP materials likely derived from the Solar System, their formation processes and provenance are poorly constrained. Stardust abundances provide a relative measure of the extent of processing that the Solar System starting materials has undergone in primitive materials. For example, among primitive meteorites silicate stardust abundances vary by over two orders of magnitude (less than 10-200 ppm). This range of abundances is ascribed to varying extents of aqueous processing in the meteorite parent bodies. The higher average silicate stardust abundances among CP-IDPs (greater than 375 ppm) are thus attributable to the lack of aqueous processing of these materials. Yet, silicate stardust abundances in IDPs also vary considerably. While the silicate stardust abundance in IDPs having anomalous N isotopic compositions was reported to be 375 ppm, the abundance in IDPs lacking N anomalies is less than 10 ppm. Furthermore, these values are significantly eclipsed among some IDPs with abundances ranging from 2,000 ppm to 10,000 ppm. Given that CP-IDPs have not been significantly affected by parent body processes, the difference in silicate stardust abundances among these IDPs must reflect varying extents of nebular processing. Here we present recent results of a systematic coordinated mineralogical/isotopic study of large cluster IDPs aimed at (1) characterizing the mineralogy of presolar silicates and (2) delineating the mineralogical and petrographic characteristics of IDPs with differing silicate stardust abundances. One of the goals of this study is

  8. Understanding and reducing statistical uncertainties in nebular abundance determinations

    NASA Astrophysics Data System (ADS)

    Wesson, R.; Stock, D. J.; Scicluna, P.

    2012-06-01

    Whenever observations are compared to theories, an estimate of the uncertainties associated with the observations is vital if the comparison is to be meaningful. However, many or even most determinations of temperatures, densities and abundances in photoionized nebulae do not quote the associated uncertainty. Those that do typically propagate the uncertainties using analytical techniques which rely on assumptions that generally do not hold. Motivated by this issue, we have developed Nebular Empirical Analysis Tool (NEAT), a new code for calculating chemical abundances in photoionized nebulae. The code carries out a standard analysis of lists of emission lines using long-established techniques to estimate the amount of interstellar extinction, calculate representative temperatures and densities, compute ionic abundances from both collisionally excited lines and recombination lines, and finally to estimate total elemental abundances using an ionization correction scheme. NEATuses a Monte Carlo technique to robustly propagate uncertainties from line flux measurements through to the derived abundances. We show that, for typical observational data, this approach is superior to analytic estimates of uncertainties. NEAT also accounts for the effect of upward biasing on measurements of lines with low signal-to-noise ratio, allowing us to accurately quantify the effect of this bias on abundance determinations. We find not only that the effect can result in significant overestimates of heavy element abundances derived from weak lines, but also that taking it into account reduces the uncertainty of these abundance determinations. Finally, we investigate the effect of possible uncertainties in R, the ratio of selective-to-total extinction, on abundance determinations. We find that the uncertainty due to this parameter is negligible compared to the statistical uncertainties due to typical line flux measurement uncertainties.

  9. Workshop on Parent-Body and Nebular Modification of Chondritic Materials

    NASA Technical Reports Server (NTRS)

    Zolensky, M. E. (Editor); Krot, A. N. (Editor); Scott, E. R. D. (Editor)

    1997-01-01

    Topics considered include: thermal Metamorphosed Antarctic CM and CI Carbonaceous Chondrites in Japanese Collections, and Transformation Processes of Phyllosilicates; use of Oxygen Isotopes to Constrain the Nebular and Asteroidal Modification of Chondritic Materials; effect of Revised Nebular Water Distribution on Enstatite Chondrite Formation; interstellar Hydroxyls in Meteoritic Chondrules: Implications for the Origin of Water in the Inner Solar System; theoretical Models and Experimental Studies of Gas-Grain Chemistry in the Solar Nebula; chemical Alteration of Chondrules on Parent Bodies; thermal Quenching of Silicate Grains in Protostellar Sources; an Experimental Study of Magnetite Formation in the Solar Nebula; the Kaidun Meteorite: Evidence for Pre- and Postaccretionary Aqueous Alteration; a Transmission Electron Microscope Study of the Matrix Mineralogy of the Leoville CV3 (Reduced-Group) Carbonaceous Chondrite: Nebular and Parent-Body Features; rubidium-Strontium Isotopic Systematic of Chondrules from the Antarctic CV Chondrites Yamato 86751 and Yamato 86009: Additional Evidence for Late Parent-Body Modification; oxygen-Fugacity Indicators in Carbonaceous Chondrites: Parent-Body Alteration or High-Temperature Nebular Oxidation; thermodynamic Modeling of Aqueous Alteration in CV Chondrites; asteroidal Modification of C and O Chondrites: Myths and Models; oxygen Fugacity in the Solar Nebular; and the History of Metal and Sulfides in Chondrites.

  10. Extended nebular emission in CALIFA early-type galaxies

    NASA Astrophysics Data System (ADS)

    Gomes, J. M.; Papaderos, P.; Kehrig, C.; Vílchez, J. M.; Lehnert, M. D.

    2015-02-01

    The morphological, spectroscopic and kinematical properties of the warm interstellar medium ( wim ) in early-type galaxies (ETGs) hold key observational constraints to nuclear activity and the buildup history of these massive quiescent systems. High-quality integral field spectroscopy (IFS) data with a wide spectral and spatial coverage, such as those from the CALIFA survey, offer a precious opportunity for advancing our understanding in this respect. We use deep IFS data from CALIFA (califa.caha.es) to study the wim over the entire extent and optical spectral range of 32 nearby ETGs. We find that all ETGs in our sample show faint (Hα equivalent width EW(Hα)~0.5 ... 2 Å) extranuclear nebular emission extending out to >=2 Petrosian50 radii. Confirming and strengthening our conclusions in Papaderos et al. (2013, hereafter P13) we argue that ETGs span a broad continuous sequence with regard to the properties of their wim , and they can be roughly subdivided into two characteristic classes. The first one (type i) comprises ETGs with a nearly constant EW(Hα)~1-3 Å in their extranuclear component, in quantitative agreement with (even though, no proof for) the hypothesis of photoionization by the post-AGB stellar component being the main driver of extended wim emission. The second class (type ii) consists of virtually wim -evacuated ETGs with a large Lyman continuum (Ly c) photon escape fraction and a very low (<=0.5 Å) EW(Hα) in their nuclear zone. These two ETG classes appear indistinguishable from one another by their LINER-specific emission-line ratios. Additionally, here we extend the classification by P13 by the class i+ which stands for a subset of type i ETGs with low-level star-forming activity in contiguous spiral-arm like features in their outermost periphery. These faint features, together with traces of localized star formation in several type i&i+ systems point to a non-negligible contribution from young massive stars to the global ionizing photon

  11. Can Lightning Produce Significant Levels of Mass-Independent Oxygen Isotopic Fractionation in Nebular Dust?

    NASA Technical Reports Server (NTRS)

    Nuth, Joseph A.; Paquette, John A.; Farquhar, Adam

    2012-01-01

    Based on recent evidence that oxide grains condensed from a plasma will contain oxygen that is mass independently fractionated compared to the initial composition of the vapor, we present a first attempt to evaluate the potential magnitude of this effect on dust in the primitive solar nebula. This assessment relies on previous studies of nebular lightning to provide reasonable ranges of physical parameters to form a very simple model to evaluate the plausibility that lightning could affect a significant fraction of nebular dust and that such effects could cause a significant change in the oxygen isotopic composition of solids in the solar nebula over time. If only a small fraction of the accretion energy is dissipated as lightning over the volume of the inner solar nebula, then a large fraction of nebular dust will be exposed to lightning. If the temperature of such bolts is a few percent of the temperatures measured in terrestrial discharges, then dust will vaporize and recondense in an ionized environment. Finally, if only a small average decrease is assumed in the O-16 content of freshly condensed dust, then over the last 5 million years of nebular accretion the average delta O-17 of the dust could increase by more than 30 per mil. We conclude that it is possible that the measured " slope 1" oxygen isotope line measured in meteorites and their components represents a time-evolution sequence of nebular dust over the last several million years of nebular evolution O-16-rich materials formed first, then escaped further processing as the average isotopic composition of the dust graduaUy became increasingly depleted in O-16 .

  12. On Bowen enhancement of the N III spectrum under solar and nebular conditions

    NASA Technical Reports Server (NTRS)

    Kastner, S. O.; Bhatia, A. K.

    1984-01-01

    Expected enhancement of the N III emission-line spectrum by the Bowen He II to O III to N III resonant photoexcitation process is computed using a six-configuration model. Preliminary comparisons with available solar and nebular observations indicate that the process may play only a small role, although photoexcitation quenching of the N III and O III far-infrared fine-structure lines is noted as a possibly important mechanism. Some features are discussed in connection with the nebular emission at 1750 A, which is suggested as an indicator of excitation class for planetary nebulae.

  13. Petrologic evolution of CM chondrites: The difficulty of discriminating between nebular and parent-body effects. [Abstract only

    NASA Technical Reports Server (NTRS)

    Kerridge, J. F.; Mcsween, H. Y., Jr.; Bunch, T. E.

    1994-01-01

    We wish to draw attention to a major controversy that has arisen in the area of CM-chondrite petrology. The problem is important because its resolution will have profound implications for ideas concerning nebular dynamics, gas-solid interactions in the nebula, and accretionary processes in the nebula, among other issues. On the one hand, cogent arguments have been presented that 'accretionary dust mantles,' were formed in the solar nebula prior to accretion of the CM parent asteroid(s). On the other hand, no-less-powerful arguments have been advanced that a significant fraction of the CM lithology is secondary, produced by aqueous alteration in the near-surface regions of an asteroid-sized object. Because most, if not all, CM chondrites are breccias, these two views could coexist harmoniously, were it not for the fact that some of the coarse-grained lithologies surrounded by 'accretion dust mantles' are themselves of apparently secondary origin. Such an observation must clearly force a reassessment of one or both of the present schools of thought. Our objective here is to stimulate such a reassessment. Four possible resolutions of this conflict may be postulated. First, perhaps nature found a way of permitting such secondary alteration to take place in the nebula. Second, maybe dust mantles could form in a regolith, rather than a nebular, environment. Third, it is possible that dust mantles around secondary lithologies are different from those around primary lithologies. Finally, perhaps formation of CM chondrites involved a more complex sequence of events than visualized so far, so that some apparently 'primary' processes postdated certain 'secondary' processes.

  14. Nebular Emission From AGN In The Ultraviolet/Optical: Linking Observations and Theory With New Generation Spectral Models

    NASA Astrophysics Data System (ADS)

    Feltre, Anna; Charlot, S.; Gutkin, J.; Hirschmann, M.; Mignoli, M.; Calura, F.; Gilli, R.; Bongiorno, A.; NEOGAL Team

    2016-10-01

    Spectroscopic studies of AGN are powerful means of probing the physical properties of the ionized gas within them. In particular, forthcoming facilities such as JWST and the E-ELT, will provide rest-frame ultraviolet and optical spectra of the very distant AGN. To lay the groundwork for the interpretation of the revolutionary datasets, we have recently computed new photoionization models of the narrow-line emitting regions (NLR) of AGN and combined them with similar models of the nebular emission from star-forming galaxies. In this talk, I will first describe how new ultraviolet and standard optical spectral diagnostics allow one to distinguish between nuclear activity and star formation. I will then present how the nebular emission from both young stars and AGN can be coupled with a new set of cosmological hydrodynamical zoom-in simulations of massive galaxies to achieve a better understanding of black hole growth and galaxy evolution with cosmic time. I will also present an innovative Bayesian fitting code that can help us best interpret current, and future, spectro-photometric data on active galaxies. In particular, the implementation of AGN photoionization calculations within this fitting tool allows us to better understand the physical properties of the AGN NLR gas. I will conclude showing some results from a recent analysis on one of the most comprehensive set of optical spectra (from VIMOS/VLT) sampling the rest-frame ultraviolet range of 90 type 2 AGN (1.5 < z < 3), drawn from the z-COSMOS deep survey.

  15. Nebular History of the Allende FoB CAI SJ101

    NASA Astrophysics Data System (ADS)

    Petaev, M. I.; Jacobsen, S. B.

    2009-03-01

    We compare petrologic and chemical characteristics of a unique FoB CAI SJ101 with the results of thermodynamic modeling of condensation of its precursors in a system of solar composition and speculate about nebular formation history of this CAI.

  16. Nebular and Stellar Dust Extinction Across the Disk of Emission-line Galaxies on Kiloparsec Scales

    NASA Astrophysics Data System (ADS)

    Hemmati, Shoubaneh; Mobasher, Bahram; Darvish, Behnam; Nayyeri, Hooshang; Sobral, David; Miller, Sarah

    2015-11-01

    We investigate the resolved kiloparsec-scale stellar and nebular dust distribution in eight star-forming galaxies at z ∼ 0.4 in the Great Observatories Origins Deep Survey fields. This is to get a better understanding of the effect of dust attenuation on measurements of physical properties and its variation with redshift. Constructing the observed spectral energy distributions (SEDs) per pixel, based on seven bands of photometric data from Hubble Space Telescope/Advanced Camera for Surveys and WFC3, we performed pixel-by-pixel SED fits to population synthesis models and estimated the small-scale distribution of stellar dust extinction. We use Hα/Hβ nebular emission line ratios from Keck/DEIMOS high-resolution spectra at each spatial resolution element to measure the amount of attenuation faced by ionized gas at different radii from the centers of galaxies. We find a good agreement between the integrated and median of resolved color excess measurements in our galaxies. The ratio of integrated nebular to stellar dust extinction is always greater than unity, but does not show any trend with stellar mass or star formation rate (SFR). We find that inclination plays an important role in the variation of the nebular to stellar excess ratio. The stellar color excess profiles are found to have higher values at the center compared to outer parts of the disk. However, for lower mass galaxies, a similar trend is not found for the nebular color excess. We find that the nebular color excess increases with stellar mass surface density. This explains the absence of radial trend in the nebular color excess in lower mass galaxies which lack a large radial variation of stellar mass surface density. Using standard conversions of SFR surface density to gas mass surface density, and the relation between dust mass surface density and color excess, we find no significant variation in the dust-to-gas ratio in regions with high gas mass surface densities over the scales probed in this

  17. The Cocoon nebula and its ionizing star: do stellar and nebular abundances agree?

    NASA Astrophysics Data System (ADS)

    García-Rojas, J.; Simón-Díaz, S.; Esteban, C.

    2014-11-01

    Context. Main-sequence massive stars embedded in an H ii region should have the same chemical abundances as the surrounding nebular gas+dust. The Cocoon nebula (IC 5146), a close-by Galactic H ii region ionized by a narrow line B0.5 V single star (BD+46 3474), is an ideal target to compare nebular and stellar abundances in detail in the same Galactic region. Aims: We investigate the chemical content of oxygen and other elements in the Cocoon nebula from two different points of view: an empirical analysis of the nebular spectrum, and a detailed spectroscopic analysis of the associated early B-type star using state-of-the-art stellar atmosphere modeling. By comparing the stellar and nebular abundances, we aim to indirectly address the long-standing problem of the discrepancy found between abundances obtained from collisionally excited lines and optical recombination lines in photoionized nebulae. Methods: We collected long-slit spatially resolved spectroscopy of the Cocoon nebula and a high-resolution optical spectrum of the ionizing star. Standard nebular techniques along with updated atomic data were used to compute the physical conditions and gaseous abundances of O, N, and S in eight apertures extracted across a semidiameter of the nebula. We performed a self-consistent spectroscopic abundance analysis of BD+46 3474 based on the atmosphere code FASTWIND to determine the stellar parameters and Si, O, and N abundances. Results: The Cocoon nebula and its ionizing star, located at a distance of 800±80 pc, have a chemical composition very similar to the Orion nebula and other B-type stars in the solar vicinity. This result agrees with the high degree of homogeneity of the present-day composition of the solar neighborhood (up to 1.5 Kpc from the Sun) as derived from the study of the local cold-gas interstellar medium. The comparison of stellar and nebular collisionally excited line abundances in the Cocoon nebula indicates that O and N gas+dust nebular values agree

  18. NEBULAR AND STELLAR DUST EXTINCTION ACROSS THE DISK OF EMISSION-LINE GALAXIES ON KILOPARSEC SCALES

    SciTech Connect

    Hemmati, Shoubaneh; Mobasher, Bahram; Darvish, Behnam; Nayyeri, Hooshang; Miller, Sarah; Sobral, David

    2015-11-20

    We investigate the resolved kiloparsec-scale stellar and nebular dust distribution in eight star-forming galaxies at z ∼ 0.4 in the Great Observatories Origins Deep Survey fields. This is to get a better understanding of the effect of dust attenuation on measurements of physical properties and its variation with redshift. Constructing the observed spectral energy distributions (SEDs) per pixel, based on seven bands of photometric data from Hubble Space Telescope/Advanced Camera for Surveys and WFC3, we performed pixel-by-pixel SED fits to population synthesis models and estimated the small-scale distribution of stellar dust extinction. We use Hα/Hβ nebular emission line ratios from Keck/DEIMOS high-resolution spectra at each spatial resolution element to measure the amount of attenuation faced by ionized gas at different radii from the centers of galaxies. We find a good agreement between the integrated and median of resolved color excess measurements in our galaxies. The ratio of integrated nebular to stellar dust extinction is always greater than unity, but does not show any trend with stellar mass or star formation rate (SFR). We find that inclination plays an important role in the variation of the nebular to stellar excess ratio. The stellar color excess profiles are found to have higher values at the center compared to outer parts of the disk. However, for lower mass galaxies, a similar trend is not found for the nebular color excess. We find that the nebular color excess increases with stellar mass surface density. This explains the absence of radial trend in the nebular color excess in lower mass galaxies which lack a large radial variation of stellar mass surface density. Using standard conversions of SFR surface density to gas mass surface density, and the relation between dust mass surface density and color excess, we find no significant variation in the dust-to-gas ratio in regions with high gas mass surface densities over the scales probed in this

  19. MEASURING NEBULAR TEMPERATURES: THE EFFECT OF NEW COLLISION STRENGTHS WITH EQUILIBRIUM AND {kappa}-DISTRIBUTED ELECTRON ENERGIES

    SciTech Connect

    Nicholls, David C.; Dopita, Michael A.; Sutherland, Ralph S.; Kewley, Lisa J.; Palay, Ethan

    2013-08-15

    In this paper we develop tools for observers to use when analyzing nebular spectra for temperatures and metallicities, with two goals: to present a new, simple method to calculate equilibrium electron temperatures for collisionally excited line flux ratios, using the latest atomic data; and to adapt current methods to include the effects of possible non-equilibrium ''{kappa}'' electron energy distributions. Adopting recent collision strength data for [O III], [S III], [O II], [S II], and [N II], we find that existing methods based on older atomic data seriously overestimate the electron temperatures, even when considering purely Maxwellian statistics. If {kappa} distributions exist in H II regions and planetary nebulae as they do in solar system plasmas, it is important to investigate the observational consequences. This paper continues our previous work on the {kappa} distribution. We present simple formulaic methods that allow observers to (1) measure equilibrium electron temperatures and atomic abundances using the latest atomic data, and (2) to apply simple corrections to existing equilibrium analysis techniques to allow for possible non-equilibrium effects. These tools should lead to better consistency in temperature and abundance measurements, and a clearer understanding of the physics of H II regions and planetary nebulae.

  20. Reconciling the Stellar and Nebular Spectra of High-redshift Galaxies

    NASA Astrophysics Data System (ADS)

    Steidel, Charles C.; Strom, Allison L.; Pettini, Max; Rudie, Gwen C.; Reddy, Naveen A.; Trainor, Ryan F.

    2016-08-01

    We present a combined analysis of rest-frame far-UV (FUV; 1000-2000 Å) and rest-frame optical (3600-7000 Å) composite spectra formed from very deep Keck/LRIS and Keck/MOSFIRE observations of a sample of 30 star-forming galaxies with z=2.40+/- 0.11, selected to be broadly representative of the full KBSS-MOSFIRE spectroscopic survey. Since the same massive stars are responsible for the observed FUV continuum and for the excitation of the observed nebular emission, a self-consistent stellar population synthesis model should simultaneously match the details of the FUV stellar+nebular continuum and—when inserted as the excitation source in photoionization models—predict all observed nebular emission line ratios. We find that only models including massive star binaries, having low stellar metallicity ({Z}* /{Z}⊙ ≃ 0.1) but relatively high nebular (ionized gas-phase) abundances ({Z}{{neb}}/{Z}⊙ ≃ 0.5), can successfully match all of the observational constraints. We show that this apparent discrepancy is naturally explained by highly super-solar O/Fe (≃ 4{--}5 {({{O}}/{Fe})}⊙ ), expected for a gas whose enrichment is dominated by the products of core-collapse supernovae. While O dominates the physics of the ionized gas (and thus the nebular emission lines), Fe dominates the extreme-UV (EUV) and FUV opacity and controls the mass-loss rate from massive stars, resulting in particularly dramatic effects for massive stars in binary systems. This high nebular excitation—caused by the hard EUV spectra of Fe-poor massive stars—is much more common at high redshift (z≳ 2) than low redshift due to systematic differences in the star formation history of typical galaxies. Based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W.M. Keck Foundation.

  1. The Importance of Nebular Continuum and Line Emission in Observations of Young Massive Star Clusters

    NASA Astrophysics Data System (ADS)

    Reines, Amy E.; Nidever, David L.; Whelan, David G.; Johnson, Kelsey E.

    2010-01-01

    In this spectroscopic study of infant massive star clusters, we find that continuum emission from ionized gas rivals the stellar luminosity at optical wavelengths. In addition, we find that nebular line emission is significant in many commonly used broadband Hubble Space Telescope (HST) filters including the F814W I-band, the F555W V-band, and the F435W B-band. Two young massive clusters (YMCs) in the nearby starburst galaxy NGC 4449 were targeted for follow-up spectroscopic observations after Reines et al. discovered an F814W I-band excess in their photometric study of radio-detected clusters in the galaxy. The spectra were obtained with the Dual Imaging Spectrograph (DIS) on the 3.5 m Apache Point Observatory (APO) telescope and have a spectral range of ~3800-9800 Å. We supplement these data with HST and Sloan Digital Sky Survey photometry of the clusters. By comparing our data to the Starburst99 and GALEV evolutionary synthesis models, we find that nebular continuum emission competes with the stellar light in our observations and that the relative contribution from the nebular continuum is largest in the U- and I-bands, where the Balmer (3646 Å) and Paschen jumps (8207 Å) are located. The spectra also exhibit strong line emission including the [S III] λλ9069, 9532 lines in the HST F814W I-band. We find that the combination of nebular continuum and line emission can account for the F814W I-band excess previously found by Reines et al. In an effort to provide a benchmark for estimating the impact of ionized gas emission on photometric observations of young massive stellar populations, we compute the relative contributions of the stellar continuum, nebular continuum, and emission lines to the total observed flux of a 3 Myr old cluster through various HST filter/instrument combinations, including filters in the Wide Field Camera 3. We urge caution when comparing observations of YMCs to evolutionary synthesis models since nebular continuum and line emission can

  2. Nebular condensation of Ga, Ge and Sb and the chemical classification of iron meteorites

    NASA Technical Reports Server (NTRS)

    Wai, C. M.; Wasson, J. T.

    1979-01-01

    The quantization of the Ga and Ge contents in iron meteorites, which is used as a key parameter in the chemical classification of iron meteorites, is discussed in terms of nebular condensation. The calculation of nebular equilibrium condensation is examined, taking into account the dependence of the activity coefficient on temperature and composition, and recent calculations of the condensation temperatures of Ga, Ge, Sb, Au, As and Cu are presented, noting that Ge is the most volatile siderophile, followed by Ga and Sb. The narrow intragroup ranges of Ga and Ge are interpreted in terms of minimal fractionation during core crystallization, while the larger ranges of Sb are attributed to its significantly smaller solid/liquid distribution coefficient in IIIAB meteorites.

  3. Nebular condensation of Ga, Ge and Sb and the chemical classification of iron meteorites

    NASA Technical Reports Server (NTRS)

    Wai, C. M.; Wasson, J. T.

    1979-01-01

    The quantization of the Ga and Ge contents in iron meteorites, which is used as a key parameter in the chemical classification of iron meteorites, is discussed in terms of nebular condensation. The calculation of nebular equilibrium condensation is examined, taking into account the dependence of the activity coefficient on temperature and composition, and recent calculations of the condensation temperatures of Ga, Ge, Sb, Au, As and Cu are presented, noting that Ge is the most volatile siderophile, followed by Ga and Sb. The narrow intragroup ranges of Ga and Ge are interpreted in terms of minimal fractionation during core crystallization, while the larger ranges of Sb are attributed to its significantly smaller solid/liquid distribution coefficient in IIIAB meteorites.

  4. VizieR Online Data Catalog: Nebular emission lines towards NGC3372 center (Damiani+, 2016)

    NASA Astrophysics Data System (ADS)

    Damiani, F.; Bonito, R.; Magrini, L.; Prisinzano, L.; Mapelli, M.; Micela, G.; Kalari, V.; Maiz Apellaniz, J.; Gilmore, G.; Randich, S.; Alfaro, E.; Flaccomio, E.; Koposov, S.; Klutsch, A.; Lanzafame, A. C.; Pancino, E.; Sacco, G. G.; Bayo, A.; Carraro, G.; Casey, A. R.; Costado, M. T.; Franciosini, E.; Hourihane, A.; Lardo, C.; Lewis, J.; Monaco, L.; Morbidelli, L.; Worley, C.; Zaggia, S.; Zwitter, T.; Dorda, R.

    2016-04-01

    Nebular emission lines of H-alpha, [NII] 6584Å, HeI 6678Å, [SII] 6717Å, [SII] 6731Å, towards the center of Carina nebula, are modeled with two gaussians each ('blue' and 'red' components). Best-fit parameters are given in the table. Line widths include the instrumental width of the Giraffe spectrograph (7km/s). Radial velocities are heliocentric. (1 data file).

  5. OPTICAL SPECTROSCOPY AND NEBULAR OXYGEN ABUNDANCES OF THE SPITZER/SINGS GALAXIES

    SciTech Connect

    Moustakas, John; Kennicutt, Robert C. Jr.; Tremonti, Christy A.; Dale, Daniel A.; Smith, John-David T.; Calzetti, Daniela

    2010-10-15

    We present intermediate-resolution optical spectrophotometry of 65 galaxies obtained in support of the Spitzer Infrared Nearby Galaxies Survey (SINGS). For each galaxy we obtain a nuclear, circumnuclear, and semi-integrated optical spectrum designed to coincide spatially with mid- and far-infrared spectroscopy from the Spitzer Space Telescope. We make the reduced, spectrophotometrically calibrated one-dimensional spectra, as well as measurements of the fluxes and equivalent widths of the strong nebular emission lines, publicly available. We use optical emission-line ratios measured on all three spatial scales to classify the sample into star-forming, active galactic nuclei (AGNs), and galaxies with a mixture of star formation and nuclear activity. We find that the relative fraction of the sample classified as star forming versus AGN is a strong function of the integrated light enclosed by the spectroscopic aperture. We supplement our observations with a large database of nebular emission-line measurements of individual H II regions in the SINGS galaxies culled from the literature. We use these ancillary data to conduct a detailed analysis of the radial abundance gradients and average H II-region abundances of a large fraction of the sample. We combine these results with our new integrated spectra to estimate the central and characteristic (globally averaged) gas-phase oxygen abundances of all 75 SINGS galaxies. We conclude with an in-depth discussion of the absolute uncertainty in the nebular oxygen abundance scale.

  6. Orbital Stability of Protoplanetary Systems in Nebular Gas and Implications for Terrestrial Planet Formation

    NASA Astrophysics Data System (ADS)

    Iwasaki, Kazunori; Ohtsuki, Keiji

    2006-06-01

    The oligarchic growth model of planetary accretion predicts the formation of protoplanets of similar sizes, and the final stage of terrestrial planet formation involves long-term orbital instability and mutual collision of protoplanets through their gravitational interaction. However, the mass of the protoplanets formed by oligarchic growth depends on the initial surface density of the protoplanetary disk, as well as the distance from the central star. In order to better understand the final stage of terrestrial planet formation in disks with various profiles, we perform orbital integration for systems of five protoplanets and examine the dependence of the orbital instability timescale of the systems on the mass of the protoplanets, Mp, both with and without nebular gas. Previous studies have shown that the timescale for orbital instability in the absence of nebular gas increases exponentially with the initial semimajor axis difference between the protoplanets. We find that the exponential constant is independent of the mass of the protoplanets, as long as the initial separation is measured in units of ~M0.29p, which is very close to the previously derived mass dependence of the critical separation for the onset of chaotic behavior in the restricted circular three-body problem. In the presence of nebular gas, on the other hand, protoplanetary systems are stabilized by gas drag and experience no orbital instability when the initial semimajor axis difference is larger than a certain critical value. Using these results, we discuss the orbital stability of protoplanetary systems in disks with various surface densities.

  7. Twisted partially pure spinors

    NASA Astrophysics Data System (ADS)

    Herrera, Rafael; Tellez, Ivan

    2016-08-01

    Motivated by the relationship between orthogonal complex structures and pure spinors, we define twisted partially pure spinors in order to characterize spinorially subspaces of Euclidean space endowed with a complex structure.

  8. "Pure" motor hemiplegia.

    PubMed Central

    Chokroverty, S; Rubino, F A

    1975-01-01

    Attenuation of cerebral evoked responses after stimulation of the median nerve in the hemiplegic limbs suggested that an apparently pure motor hemiplegia in some patients may not have pure involvement of the corticospinal system. Frontoparietal metastasis, infarction in basis pontis and medullary pyramid, and occlusion of internal carotid artery in the neck resulted in pure motor hemiplegia in some individuals. Images PMID:1185228

  9. Contamination of Broadband Photometry by Nebular Emission in High-redshift Galaxies: Investigations with Keck's MOSFIRE Near-infrared Spectrograph

    NASA Astrophysics Data System (ADS)

    Schenker, Matthew A.; Ellis, Richard S.; Konidaris, Nick P.; Stark, Daniel P.

    2013-11-01

    Earlier work has raised the potential importance of nebular emission in the derivation of the physical characteristics of high-redshift Lyman break galaxies. Within certain redshift ranges, and especially at z ~= 6-7, such lines may be strong enough to reduce estimates of the stellar masses and ages of galaxies compared with those derived assuming the broadband photometry represents stellar light alone. To test this hypothesis at the highest redshifts where such lines can be probed with ground-based facilities, we examine the near-infrared spectra of a representative sample of 28 3.0 < z < 3.8 Lyman break galaxies using the newly commissioned MOSFIRE near-infrared spectrograph at the Keck I telescope. We use these data to derive the rest-frame equivalent widths (EWs) of [O III] emission and show that these are comparable with estimates derived using the spectral energy distribution (SED) fitting technique introduced for sources of known redshift by Stark et al. Although our current sample is modest, its [O III] EW distribution is consistent with that inferred for Hα based on SED fitting of Stark et al.'s larger sample of 3.8 < z < 5 galaxies. For a subset of survey galaxies, we use the combination of optical and near-infrared spectroscopy to quantify kinematics of outflows in z ~= 3.5 star-forming galaxies and discuss the implications for reionization measurements. The trends we uncover underline the dangers of relying purely on broadband photometry to estimate the physical properties of high-redshift galaxies and emphasize the important role of diagnostic spectroscopy.

  10. CONTAMINATION OF BROADBAND PHOTOMETRY BY NEBULAR EMISSION IN HIGH-REDSHIFT GALAXIES: INVESTIGATIONS WITH KECK'S MOSFIRE NEAR-INFRARED SPECTROGRAPH

    SciTech Connect

    Schenker, Matthew A; Ellis, Richard S; Konidaris, Nick P; Stark, Daniel P

    2013-11-01

    Earlier work has raised the potential importance of nebular emission in the derivation of the physical characteristics of high-redshift Lyman break galaxies. Within certain redshift ranges, and especially at z ≅ 6-7, such lines may be strong enough to reduce estimates of the stellar masses and ages of galaxies compared with those derived assuming the broadband photometry represents stellar light alone. To test this hypothesis at the highest redshifts where such lines can be probed with ground-based facilities, we examine the near-infrared spectra of a representative sample of 28 3.0 < z < 3.8 Lyman break galaxies using the newly commissioned MOSFIRE near-infrared spectrograph at the Keck I telescope. We use these data to derive the rest-frame equivalent widths (EWs) of [O III] emission and show that these are comparable with estimates derived using the spectral energy distribution (SED) fitting technique introduced for sources of known redshift by Stark et al. Although our current sample is modest, its [O III] EW distribution is consistent with that inferred for Hα based on SED fitting of Stark et al.'s larger sample of 3.8 < z < 5 galaxies. For a subset of survey galaxies, we use the combination of optical and near-infrared spectroscopy to quantify kinematics of outflows in z ≅ 3.5 star-forming galaxies and discuss the implications for reionization measurements. The trends we uncover underline the dangers of relying purely on broadband photometry to estimate the physical properties of high-redshift galaxies and emphasize the important role of diagnostic spectroscopy.

  11. Modelling the nebular emission from primeval to present-day star-forming galaxies

    NASA Astrophysics Data System (ADS)

    Gutkin, Julia; Charlot, Stéphane; Bruzual, Gustavo

    2016-10-01

    We present a new model of the nebular emission from star-forming galaxies in a wide range of chemical compositions, appropriate to interpret observations of galaxies at all cosmic epochs. The model relies on the combination of state-of-the-art stellar population synthesis and photoionization codes to describe the ensemble of H II regions and the diffuse gas ionized by young stars in a galaxy. A main feature of this model is the self-consistent yet versatile treatment of element abundances and depletion on to dust grains, which allows one to relate the observed nebular emission from a galaxy to both gas-phase and dust-phase metal enrichment. We show that this model can account for the rest-frame ultraviolet and optical emission-line properties of galaxies at different redshifts and find that ultraviolet emission lines are more sensitive than optical ones to parameters such as C/O abundance ratio, hydrogen gas density, dust-to-metal mass ratio and upper cut-off of the stellar initial mass function. We also find that, for gas-phase metallicities around solar to slightly subsolar, widely used formulae to constrain oxygen ionic fractions and the C/O ratio from ultraviolet and optical emission-line luminosities are reasonable faithful. However, the recipes break down at non-solar metallicities, making them inappropriate to study chemically young galaxies. In such cases, a fully self-consistent model of the kind presented in this paper is required to interpret the observed nebular emission.

  12. [O II] nebular emission from Mg II absorbers: star formation associated with the absorbing gas

    NASA Astrophysics Data System (ADS)

    Joshi, Ravi; Srianand, Raghunathan; Petitjean, Patrick; Noterdaeme, Pasquier

    2017-10-01

    We present nebular emission associated with 198 strong Mg II absorbers at 0.35 ≤z ≤ 1.1 in the fibre spectra of quasars from the Sloan Digital Sky Survey. Measured [O II] luminosities (L_[O II]) are typical of sub-L⋆ galaxies with derived star formation rate (uncorrected for fibre losses and dust reddening) in the range of 0.5-20 M⊙ yr-1. Typically less than ∼3 per cent of the Mg II systems with rest equivalent width, W2796≥2Å, show L_[O II] ≥0.3 L^{\\star }_[O II]. The detection rate is found to increase with increasing W2796 and z. No significant correlation is found between W2796 and L_[O II] even when we restrict the samples to narrow z ranges. A strong correlation is seen between L_[O II] and z. While this is expected from the luminosity evolution of galaxies, we show that finite fibre size plays a very crucial role in this correlation. The measured nebular line ratios (like [O III]/[O II] and [O III]/H β) and their z evolution are consistent with those of galaxies detected in deep surveys. Based on the median stacked spectra, we infer the average metallicity (log Z ∼8.3), ionization parameter (log q∼7.5) and stellar mass (log (M/M⊙) ∼ 9.3). The Mg II systems with nebular emission typically have W2796 ≥2 Å, Mg II doublet ratio close to 1 and W(Fe II λ2600)/W2796∼0.5 as often seen in damped Ly α and 21-cm absorbers at these redshifts. This is the biggest reported sample of [O II] emission from Mg II absorbers at low-impact parameters ideally suited for probing various feedback processes at play in z ≤ 1 galaxies.

  13. NO STRIPPED HYDROGEN IN THE NEBULAR SPECTRA OF NEARBY TYPE Ia SUPERNOVA 2011fe

    SciTech Connect

    Shappee, Benjamin J.; Stanek, K. Z.; Pogge, R. W.; Garnavich, P. M. E-mail: kstanek@astronomy.ohio-state.edu E-mail: pgarnavi@nd.edu

    2013-01-01

    A generic prediction of the single-degenerate model for Type Ia supernovae (SNe Ia) is that a significant amount of material will be stripped from the donor star ({approx}0.5 M{sub Sun} for a giant donor and {approx}0.15 M{sub Sun} for a main-sequence donor) by the supernova ejecta. This material, excited by gamma-rays from radioactive decay, would then produce relatively narrow ({approx}<1000 km s{sup -1}) emission features observable once the supernova enters the nebular phase. Such emission has never been detected, which already provides strong constraints on Type Ia progenitor models. In this Letter, we report the deepest limit yet on the presence of H{alpha} emission originating from the stripped hydrogen in the nebular spectrum of an SN Ia obtained using a high signal-to-noise spectrum of the nearby normal SN Ia 2011fe 274 days after B-band maximum light with the Large Binocular Telescope's Multi-Object Double Spectrograph. We put a conservative upper limit on the H{alpha} flux of 3.14 Multiplication-Sign 10{sup -17} erg s{sup -1} cm{sup -2}, which corresponds to a luminosity of 1.57 Multiplication-Sign 10{sup 35} erg s{sup -1}. By scaling models from the literature, our flux limit translates into an upper limit of {approx}<0.001 M{sub Sun} of stripped material. This is an order of magnitude stronger than previous limits. SN 2011fe was a typical SN Ia, special only in its proximity, and we argue that lack of hydrogen emission in its nebular spectrum adds yet another strong constraint on the single-degenerate class of models for SNe Ia.

  14. Self-similar collapse in nebular disk and the Titius-Bode law.

    NASA Astrophysics Data System (ADS)

    Li, X. Q.; Zhang, H.; Li, Q. B.

    1995-12-01

    Nonlinear development and evolution of density disturbances in nebular disk are examined on the basis of our previous study(Li & Zhang 1994). It is shown that the perturbed density is unstable with respect to self-modulation, leading to the formation of the density field localization; in the nonlinear stage of the instability, development of the localized field will lead to collapse. For the case of self-similar collapse, perturbed density inially increases with time and then tends to form of steady rings with very large but limit amplitudes; and their distances r_n_ from the center form a geometric progression, which is similar to the Titius-Bode law.

  15. Mid- and Far-IR Spectroscopy of the Nebular Phase of SN1987A

    NASA Technical Reports Server (NTRS)

    Wooden, Diane; Witteborn, Fred C. (Technical Monitor)

    1997-01-01

    The mid- and far-infrared (IR) spectra of the nebular phase of SM 987A spans 250 days through more than 1000 days after the event. Analysis of the spectra, largely obtained from the Kuiper Airborne Observatory, leads to a rich picture of the structure of the supernebula. The evidence for dust grain formation. In the nebula after about 580 days will be reviewed. The dust continuum emission spectrum was gray and dust appears to have condensed in optically thick 'clumps' throughout a significant fraction of the nebula. Additional information is contained in the original extended abstract.

  16. Dust Attenuation of the Nebular Regions of z ~ 2 Star-forming Galaxies: Insight from UV, IR, and Emission Lines

    NASA Astrophysics Data System (ADS)

    De Barros, S.; Reddy, N.; Shivaei, I.

    2016-04-01

    We use a sample of 149 spectroscopically confirmed UV-selected galaxies at z ˜ 2 to investigate the relative dust attenuation of the stellar continuum and the nebular emission lines. For each galaxy in the sample, at least one rest-frame optical emission line (Hα/[N ii] λ6583 or [O iii] λ5007) measurement has been taken from the litterature, and 41 galaxies have additional Spitzer/MIPS 24 μm observations that are used to infer infrared luminosities. We use a spectral energy distribution (SED) fitting code that predicts nebular line strengths when fitting the stellar populations of galaxies in our sample, and we perform comparisons between the predictions of our models and the observed/derived physical quantities. We find that on average our code is able to reproduce all the physical quantities (e.g., UV β slopes, infrared luminosities, emission line fluxes), but we need to apply a higher dust correction to the nebular emission compared to the stellar emission for the largest star formation rate (SFR) (log SFR/M⊙ yr-1 > 1.82, Salpeter initial mass function). We find a correlation between SFR and the difference in nebular and stellar color excesses, which could resolve the discrepant results regarding nebular dust correction at z ˜ 2 from previous studies.

  17. Pulsars as Gamma-Rays Sources: Nebular Shocks and Magnetospheric Gaps

    NASA Astrophysics Data System (ADS)

    Arons, Jonathan

    1996-01-01

    agreement with the total current flow predicted by the early Goldreich and Julian (1969) model. The total pair outflow is shown to be about 5 × 1037 pairs per second, in good agreement with the particle flux required to explain the nebular X—ray source. The energetics of particle acceleration within the magnetospheres of rotation powered pulsars and the consequences for pulsed gamma ray emission are also briefly discussed. The gamma ray luminosity above 100 MeV is shown to scale in proportion to Ė {/R 1/2}, as is in accord with some of the simplest ideas about “polar cap” models. Models based on acceleration in the outer magnetosphere are also briefly discussed.

  18. 7 CFR 916.16 - Pure grower or pure producer.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Pure grower or pure producer. 916.16 Section 916.16... Order Regulating Handling Definitions § 916.16 Pure grower or pure producer. (a) Pure grower means any...); or (2) Who produces and handles his or her own product; Provided, That a pure grower can pack...

  19. 7 CFR 917.8 - Pure grower or pure producer.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Pure grower or pure producer. 917.8 Section 917.8... CALIFORNIA Order Regulating Handling Definitions § 917.8 Pure grower or pure producer. (a) For peaches, pure... packing business); or (2) Who produces and handles his or her own product; Provided, That a pure...

  20. 7 CFR 916.16 - Pure grower or pure producer.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Pure grower or pure producer. 916.16 Section 916.16... Order Regulating Handling Definitions § 916.16 Pure grower or pure producer. (a) Pure grower means any...); or (2) Who produces and handles his or her own product; Provided, That a pure grower can pack...

  1. 7 CFR 917.8 - Pure grower or pure producer.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Pure grower or pure producer. 917.8 Section 917.8... CALIFORNIA Order Regulating Handling Definitions § 917.8 Pure grower or pure producer. (a) For peaches, pure... packing business); or (2) Who produces and handles his or her own product; Provided, That a pure...

  2. Preservation of a nebular mg-Delta O-17 correlation during partial melting of ureilites

    NASA Astrophysics Data System (ADS)

    Goodrich, Cyrena A.

    1997-03-01

    Ureilites are a class of over 50 achondrites that display a bewildering mix of igneous and primitive characteristics. This work addresses the apparent incompatibility of the mineralogy and lithophile element chemistry of ureilites with their oxygen isotopic characteristics. One problem presented by the oxygen isotopic characteristics of ureilites is that ureilites show a correlation of the olivine and pyroxene mg ratio with delta O-17. Such correlations are otherwise observed only in very primitive materials such as among chondrules and their rims in Allende, and among the H-L-LL ordinary chondrite groups. The question is whether a nebular mg-delta O-17 correlation could survive the partial melting necessary to produce ureilites from chondritic material. Goodrich (1992) assumed that it could not, because ureilites would not be expected to have all undergone precisely the same degree of melting. Results of model calculations are presented here to test this assumption. From the results, it does appear that a nebular mg-delta O-17 correlation could survive the partial melting required to produce ureilites from chondritic material. Questions, however, still remain, and are posed at the conclusion of the paper.

  3. STELLAR AUTOPSIES: THE ANALYSIS OF TWO GRB-SNE IN THE NEBULAR PHASE

    NASA Astrophysics Data System (ADS)

    Villar, Victoria; Soderberg, A. M.; Milisavljevic, D.; Drout, M.

    2014-01-01

    Spectroscopy and photometry of core-collapse supernovae (SNe) during the nebular phase (T>=40 days) can be used to constrain explosion characteristics, including asymmetry. Here we model the nebular phase light curves of two hydrogen-stripped SNe, SN 2003dh and SN 2006aj, associated with gamma-ray bursts 030329 and 060218, respectively. We estimate the kinetic energy, nickel mass and ejected mass of the explosions. Using Hubble Legacy data in the F814W [I-band], F625W [R-band], F606W [V-band] and F435W [B-band] filters taken between 50 and 450 days after the gamma ray bursts, we reconstruct the bolometric light curve and apply a spherically symmetric, radiative decay model. For SN 2003dh, we find a nickel mass of ~0.35 M_solar, and for SN 2006aj we find a nickel mass of ~0.18 M_solar. Both are in good agreement with estimates from early photometric data suggesting minimal asymmetry within the SN explosion. We compare our results with other supernovae associated with gamma ray bursts. This work is supported in part by the NSF REU and DOD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution.

  4. Lunar and Planetary Science XXXV: From Ancient Mists: Presolar and Nebular Processes

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The session "From Ancient Mists: Presolar and Nebular Processes" included the following reports: Interpretation of the Meteoritic Extinct Radioactivity - Mean Life Relation; On the Issue of Molybdenum Isotopic Anomalies in Meteorites: Is It Still "FUN"?; (26Al/27Al)o of the Solar Nebula Inferred from Al-Mg Systematic in Bulk CAIs from CV3 Chondrites; Magnesium Isotopic Compositions of Igneous CAIs in the CR Carbonaceous Chondrites: Evidence for an Early and Late-stage Melting of CAIs; The 26Al-26Mg Chronology of a Type C CAI and POIs in Ningqiang Carbonaceous Chondrite; Bulk Compositions of CAIs and Al-rich Chondrules: Implications of the Reversal of the Anorthite / Forsterite Condensation Sequence at Low Nebular Pressures; Synthesis of Refractory Minerals by High-Temperature Condensation of a Gas of Solar Composition; Elemental and Isotopic Fractionation by Diffusion-limited Evaporation; "Nonideal" Isotopic Fractionation Behavior of Magnesium in Evaporation Residues; Determination of Primordial Refractory Inclusion Compositions; Zoning Patterns in Spinel from Type B Ca-Al-rich Inclusions: Constraints on Sub-Solidus Thermal History; Radial Migration of Materials from Inner to Outer Solar Nebula: Evidence from Meteorite Matrix; and Refractory Forsterites in Chondritic Meteorites, a Link Between CAIs and Chondrules.

  5. Remarkable Rise in Electron-Ion Recombination of O II for Low Temperature Nebular Plasmas

    NASA Astrophysics Data System (ADS)

    Nahar, Sultana; Pradhan, Anil

    2011-05-01

    Recombination is dominant in cooler nebular plasmas and recombination lines (RCL) of O II are commonly detected. Collisionally excited lines (CEL) are also common. But a longstanding discrepancy of lower and higher oxygen abundance exists predicted from the RCL and CEL respectively. This is a puzzle since existent atomic parameters for O II are known to be accurate. We have studied the low energy photoionization and low temperature recombination of O II using the unified method based on relativistic Breit-Pauli R-matrix method and close coupling approximation. We find that the fine structure effects in the low temperature region, studied for the first time, cause considerable enhancement in electron-ion recombination rates. The enhancement comes from the intense narrow resonances, allowed in fine structure but not in LS coupling approximation, in a small energy region right at the ionization threshold. Due to the small energy range that contains these resonances, experiment was unable to detect them. We will present detailed features and recombination rates at low temperature which are expected to narrow the gap of discrepancy in oxygem abundance in nebular plasmas. Partial supports: NSF, DOE

  6. Lunar and Planetary Science XXXV: From Ancient Mists: Presolar and Nebular Processes

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The session "From Ancient Mists: Presolar and Nebular Processes" included the following reports: Interpretation of the Meteoritic Extinct Radioactivity - Mean Life Relation; On the Issue of Molybdenum Isotopic Anomalies in Meteorites: Is It Still "FUN"?; (26Al/27Al)o of the Solar Nebula Inferred from Al-Mg Systematic in Bulk CAIs from CV3 Chondrites; Magnesium Isotopic Compositions of Igneous CAIs in the CR Carbonaceous Chondrites: Evidence for an Early and Late-stage Melting of CAIs; The 26Al-26Mg Chronology of a Type C CAI and POIs in Ningqiang Carbonaceous Chondrite; Bulk Compositions of CAIs and Al-rich Chondrules: Implications of the Reversal of the Anorthite / Forsterite Condensation Sequence at Low Nebular Pressures; Synthesis of Refractory Minerals by High-Temperature Condensation of a Gas of Solar Composition; Elemental and Isotopic Fractionation by Diffusion-limited Evaporation; "Nonideal" Isotopic Fractionation Behavior of Magnesium in Evaporation Residues; Determination of Primordial Refractory Inclusion Compositions; Zoning Patterns in Spinel from Type B Ca-Al-rich Inclusions: Constraints on Sub-Solidus Thermal History; Radial Migration of Materials from Inner to Outer Solar Nebula: Evidence from Meteorite Matrix; and Refractory Forsterites in Chondritic Meteorites, a Link Between CAIs and Chondrules.

  7. Time development of a perturbed-spherical nucleus in a pure supercooled liquid. I - Power-law growth of morphological instabilities. II - Nonlinear development

    NASA Technical Reports Server (NTRS)

    Pines, V.; Zlatkowski, M.; Chait, A.

    1990-01-01

    The linear growth stage of the morphological instabilities developing at the liquid-solid interface during crystal growth from an axisymmetric spherical nucleus is analyzed. The corresponding growth rate parameters are calculated numerically, and it is shown that morphological instabilities for free growth evolve according to a power law in agreement with WKB results and contrary to an exponential law found in a quasi-stationary approximation. The time evolution of an arbitrary perturbed liquid-solid interface from a linear into the nonlinear stage is studied. The initial perturbations include the eigenfunctions for the linear problem, localized perturbations of the grain-boundary type, and a stochastic noise. It is shown that the perturbations grow and spread in a wavelike manner. The formation of a predendritic growth stage is characterized by establishment of constant values of tip radius and velocity.

  8. Purely lytic osteosarcoma

    SciTech Connect

    De Santos, L.A.; Eideken, B.

    1982-11-01

    The radiographic features of 42 purely lytic osteosarcomas are presented. Purely lytic osteosarcoma is identified as a lytic lesion of bone with no demonstrable osteoid matrix by conventional radiographic modalities. Purely lytic osteosarcoma represented 13.7% of a group of 305 osteosarcomas. The most common presentation was that of a lytic illdefined lesion with a moderate to large extraosseous mass component. Nine lesions presented with benign radiographic features. The differential diagnosis is outlined. The need for awareness of this type of presentation of osteosarcoma is stressed.

  9. Pure-quartic solitons

    PubMed Central

    Blanco-Redondo, Andrea; Martijn, de Sterke C.; Sipe, J.E.; Krauss, Thomas F.; Eggleton, Benjamin J.; Husko, Chad

    2016-01-01

    Temporal optical solitons have been the subject of intense research due to their intriguing physics and applications in ultrafast optics and supercontinuum generation. Conventional bright optical solitons result from the interaction of anomalous group-velocity dispersion and self-phase modulation. Here we experimentally demonstrate a class of bright soliton arising purely from the interaction of negative fourth-order dispersion and self-phase modulation, which can occur even for normal group-velocity dispersion. We provide experimental and numerical evidence of shape-preserving propagation and flat temporal phase for the fundamental pure-quartic soliton and periodically modulated propagation for the higher-order pure-quartic solitons. We derive the approximate shape of the fundamental pure-quartic soliton and discover that is surprisingly Gaussian, exhibiting excellent agreement with our experimental observations. Our discovery, enabled by precise dispersion engineering, could find applications in communications, frequency combs and ultrafast lasers. PMID:26822758

  10. To Cool is to Accrete: Analytic Scalings for Nebular Accretion of Planetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Lee, Eve J.; Chiang, Eugene

    2015-09-01

    Planets acquire atmospheres from their parent circumstellar disks. We derive a general analytic expression for how the atmospheric mass grows with time t as a function of the underlying core mass {M}{core} and nebular conditions, including the gas metallicity Z. Planets accrete as much gas as can cool: an atmosphere's doubling time is given by its Kelvin-Helmholtz time. Dusty atmospheres behave differently from atmospheres made dust-free by grain growth and sedimentation. The gas-to-core mass ratio (GCR) of a dusty atmosphere scales as GCR \\propto {t}0.4{M}{core}1.7{Z}-0.4{μ }{rcb}3.4, where {μ }{rcb}\\propto 1/(1-Z) (for Z not too close to 1) is the mean molecular weight at the innermost radiative-convective boundary. This scaling applies across all orbital distances and nebular conditions for dusty atmospheres; their radiative-convective boundaries, which regulate cooling, are not set by the external environment, but rather by the internal microphysics of dust sublimation, H2 dissociation, and the formation of H-. By contrast, dust-free atmospheres have their radiative boundaries at temperatures {T}{rcb} close to nebular temperatures {T}{out}, and grow faster at larger orbital distances where cooler temperatures, and by extension lower opacities, prevail. At 0.1 AU in a gas-poor nebula, GCR \\propto {t}0.4{T}{rcb}-1.9{M}{core}1.6{Z}-0.4{μ }{rcb}3.3, while beyond 1 AU in a gas-rich nebula, GCR \\propto {t}0.4{T}{rcb}-1.5{M}{core}1{Z}-0.4{μ }{rcb}2.2. We confirm our analytic scalings against detailed numerical models for objects ranging in mass from Mars (0.1{M}\\oplus ) to the most extreme super-Earths (10-20{M}\\oplus ), and explain why heating from planetesimal accretion cannot prevent the latter from undergoing runaway gas accretion.

  11. The origin of chromitic chondrules and the volatility of Cr under a range of nebular conditions

    NASA Technical Reports Server (NTRS)

    Krot, Alexander; Ivanova, Marina A.; Wasson, John T.

    1993-01-01

    We characterize ten chromatic chondrules, two spinelian chondrules andd one spinel-bearing chondrule and summarize data for 120 chromitic inclusions discovered in an extensive survey of ordinary chondrites. Compositional and petrographic evidence suggests that chromitic chondrules and inclusions are closely related. The Cr/(Cr + Al) ratios in the spinal of these objects range from 0.5 to 0.9 and bulk Al2O3 contents are uniformly high (greater than 10 wt%, except for one with 8 wt%). No other elements having comparable solar abundances are so stongly enriched, and alkali feldspar and merrillite are more common than in normal chondrules. The Cr/Mg ratios in chromitic chondrules are 180-750 times the ratios in the bulk chondrite. With the possible exception of magnetic clumping of chromite in the presolar cloud, mechanical processes cannot account for this enrichment. Examination of nebular equilibrium processes shows that 50%-condensation temperatures of Cr at pH2/pH2O of 1500 are several tens of degrees below those of Mg as Mg2SiO4; the condensation of Cr is primarily as MgCr2O4 dissolved in MgAl2O4 at nebular pressures of 10(exp -4) atm or below. At pH2 = 10(exp -3) atm condesation as Cr in Fe-Ni is favored. Making the nebula much more oxidizing reduces the difference in condensation temperatures but Mg remains more refractory. We conclude that nebular equilibrium processes are not responsible for the enhanced Cr/Mg ratios. We propose that both Cr and Al became enriched in residues formed by incomplete evaporation of presolar lumps. We suggest that spinals remained as solid phases when the bulk of the silicates were incorporated into the evaporating melt; vaporization of Al and Cr were inhibited by the slow kinetics of diffusion. Subsequent melting and crystallization of these residues fractionated Cr from Al. The resulting materials constituted major components in the precursors of chromitic chondrules. Our model implies that chromitic chondrules and inclusions

  12. Geomorphology: Pure and applied

    SciTech Connect

    Hart, M.G.

    1986-01-01

    The book summarizes the history of intellectual debate in geomorphology and describes modern developments both ''pure'' and ''applied.'' The history begins well before W.M. Davis and follows through to such debates as those concerned with the Pleistocene. Modern developments in pure geomorphology are cast in terms of chapters on form, process, materials, and methods analysis. The applied chapters concentrate on environmental hazards and resources, and their management.

  13. New experimental methodology, setup and LabView program for accurate absolute thermoelectric power and electrical resistivity measurements between 25 and 1600 K: application to pure copper, platinum, tungsten, and nickel at very high temperatures.

    PubMed

    Abadlia, L; Gasser, F; Khalouk, K; Mayoufi, M; Gasser, J G

    2014-09-01

    In this paper we describe an experimental setup designed to measure simultaneously and very accurately the resistivity and the absolute thermoelectric power, also called absolute thermopower or absolute Seebeck coefficient, of solid and liquid conductors/semiconductors over a wide range of temperatures (room temperature to 1600 K in present work). A careful analysis of the existing experimental data allowed us to extend the absolute thermoelectric power scale of platinum to the range 0-1800 K with two new polynomial expressions. The experimental device is controlled by a LabView program. A detailed description of the accurate dynamic measurement methodology is given in this paper. We measure the absolute thermoelectric power and the electrical resistivity and deduce with a good accuracy the thermal conductivity using the relations between the three electronic transport coefficients, going beyond the classical Wiedemann-Franz law. We use this experimental setup and methodology to give new very accurate results for pure copper, platinum, and nickel especially at very high temperatures. But resistivity and absolute thermopower measurement can be more than an objective in itself. Resistivity characterizes the bulk of a material while absolute thermoelectric power characterizes the material at the point where the electrical contact is established with a couple of metallic elements (forming a thermocouple). In a forthcoming paper we will show that the measurement of resistivity and absolute thermoelectric power characterizes advantageously the (change of) phase, probably as well as DSC (if not better), since the change of phases can be easily followed during several hours/days at constant temperature.

  14. New experimental methodology, setup and LabView program for accurate absolute thermoelectric power and electrical resistivity measurements between 25 and 1600 K: Application to pure copper, platinum, tungsten, and nickel at very high temperatures

    NASA Astrophysics Data System (ADS)

    Abadlia, L.; Gasser, F.; Khalouk, K.; Mayoufi, M.; Gasser, J. G.

    2014-09-01

    In this paper we describe an experimental setup designed to measure simultaneously and very accurately the resistivity and the absolute thermoelectric power, also called absolute thermopower or absolute Seebeck coefficient, of solid and liquid conductors/semiconductors over a wide range of temperatures (room temperature to 1600 K in present work). A careful analysis of the existing experimental data allowed us to extend the absolute thermoelectric power scale of platinum to the range 0-1800 K with two new polynomial expressions. The experimental device is controlled by a LabView program. A detailed description of the accurate dynamic measurement methodology is given in this paper. We measure the absolute thermoelectric power and the electrical resistivity and deduce with a good accuracy the thermal conductivity using the relations between the three electronic transport coefficients, going beyond the classical Wiedemann-Franz law. We use this experimental setup and methodology to give new very accurate results for pure copper, platinum, and nickel especially at very high temperatures. But resistivity and absolute thermopower measurement can be more than an objective in itself. Resistivity characterizes the bulk of a material while absolute thermoelectric power characterizes the material at the point where the electrical contact is established with a couple of metallic elements (forming a thermocouple). In a forthcoming paper we will show that the measurement of resistivity and absolute thermoelectric power characterizes advantageously the (change of) phase, probably as well as DSC (if not better), since the change of phases can be easily followed during several hours/days at constant temperature.

  15. New experimental methodology, setup and LabView program for accurate absolute thermoelectric power and electrical resistivity measurements between 25 and 1600 K: Application to pure copper, platinum, tungsten, and nickel at very high temperatures

    SciTech Connect

    Abadlia, L.; Mayoufi, M.; Gasser, F.; Khalouk, K.; Gasser, J. G.

    2014-09-15

    In this paper we describe an experimental setup designed to measure simultaneously and very accurately the resistivity and the absolute thermoelectric power, also called absolute thermopower or absolute Seebeck coefficient, of solid and liquid conductors/semiconductors over a wide range of temperatures (room temperature to 1600 K in present work). A careful analysis of the existing experimental data allowed us to extend the absolute thermoelectric power scale of platinum to the range 0-1800 K with two new polynomial expressions. The experimental device is controlled by a LabView program. A detailed description of the accurate dynamic measurement methodology is given in this paper. We measure the absolute thermoelectric power and the electrical resistivity and deduce with a good accuracy the thermal conductivity using the relations between the three electronic transport coefficients, going beyond the classical Wiedemann-Franz law. We use this experimental setup and methodology to give new very accurate results for pure copper, platinum, and nickel especially at very high temperatures. But resistivity and absolute thermopower measurement can be more than an objective in itself. Resistivity characterizes the bulk of a material while absolute thermoelectric power characterizes the material at the point where the electrical contact is established with a couple of metallic elements (forming a thermocouple). In a forthcoming paper we will show that the measurement of resistivity and absolute thermoelectric power characterizes advantageously the (change of) phase, probably as well as DSC (if not better), since the change of phases can be easily followed during several hours/days at constant temperature.

  16. Evidence for primitive nebular components in chondrules from the Chainpur chondrite

    NASA Astrophysics Data System (ADS)

    Grossman, J. N.; Wasson, J. T.

    1982-06-01

    In view of the fact that the least equilibrated ordinary chondrites contain chondrules that have changed little since the time of their formation in the early solar system, and are therefore excellent indicators of the physical and chemical nature of the solar nebula, 36 chondrules were separated from the Chainpur chondrite and analyzed for 20 elements and petrographic properties. The dominant nebular components found are: (1) a mixture of metal and sulfide whose composition is similar to whole rock metal and sulfide, (2) Ir-rich metal, (3) olivine-rich silicates, (4) pyroxene-rich silicates, and possibly (5) a component containing the more volatile lithophiles. Although etching experiments confirm that chondrule rims are enriched in metal, troilite and moderately volatile elements relative to the bulk chondrules, a large fraction of the volatiles remains in the unetched interior.

  17. DEPENDENCE OF NEBULAR HEAVY-ELEMENT ABUNDANCE ON H I CONTENT FOR SPIRAL GALAXIES

    SciTech Connect

    Robertson, Paul; Shields, Gregory A.; Wright, Audrey; Dave, Romeel; Blanc, Guillermo A.

    2013-08-10

    We analyze the galactic H I content and nebular log (O/H) for 60 spiral galaxies in the Moustakas et al. (2006a) spectral catalog. After correcting for the mass-metallicity relationship, we show that the spirals in cluster environments show a positive correlation for log (O/H) on DEF, the galactic H I deficiency parameter, extending the results of previous analyses of the Virgo and Pegasus I clusters. Additionally, we show for the first time that galaxies in the field obey a similar dependence. The observed relationship between H I deficiency and galactic metallicity resembles similar trends shown by cosmological simulations of galaxy formation including inflows and outflows. These results indicate the previously observed metallicity-DEF correlation has a more universal interpretation than simply a cluster's effects on its member galaxies. Rather, we observe in all environments the stochastic effects of metal-poor infall as minor mergers and accretion help to build giant spirals.

  18. Chemistry of primitive solar material. [nebular hypothesis of planetary systems formation

    NASA Technical Reports Server (NTRS)

    Barshay, S. S.; Lewis, J. S.

    1976-01-01

    The paper reviews chemical processes that occurred in the cooler outer regions of the primitive solar nebula (PSN) at the time of intimate chemical contact between the preplanetary condensate and the nebular gas. The elemental composition of the PSN is discussed, the 15 most abundant elements in it are listed, and numerical models of it are examined. Various condensation models are described and tested against observed properties of the planets, their satellites, and the asteroids. The chemistry of abundant volatile elements in the PSN is investigated along with stability limits of graphite in a solar-composition gas, regions of dominance of the most abundant carbon-containing gas species in the same gas, and implications of the moon's composition for its origin. Some theories that have been proposed as alternatives to the condensation models are noted.

  19. Chemistry of primitive solar material. [nebular hypothesis of planetary systems formation

    NASA Technical Reports Server (NTRS)

    Barshay, S. S.; Lewis, J. S.

    1976-01-01

    The paper reviews chemical processes that occurred in the cooler outer regions of the primitive solar nebula (PSN) at the time of intimate chemical contact between the preplanetary condensate and the nebular gas. The elemental composition of the PSN is discussed, the 15 most abundant elements in it are listed, and numerical models of it are examined. Various condensation models are described and tested against observed properties of the planets, their satellites, and the asteroids. The chemistry of abundant volatile elements in the PSN is investigated along with stability limits of graphite in a solar-composition gas, regions of dominance of the most abundant carbon-containing gas species in the same gas, and implications of the moon's composition for its origin. Some theories that have been proposed as alternatives to the condensation models are noted.

  20. Atomic Data for Nebular Abundance Determinations: Photoionization and Recombination Properties of Xenon Ions

    NASA Astrophysics Data System (ADS)

    Sterling, Nicholas C.; Kerlin, Austin B.

    2016-01-01

    We present preliminary results of a study of the photoionization (PI) and recombination properties of low-charge Xe ions. The abundances of neutron(n)-capture elements (atomic number Z > 30) are of interest in planetary nebulae (PNe) since they can be enriched by slow n-capture nucleosynthesis (the ``s-process'') in the progenitor asymptotic giant branch (AGB) stars. Xe is particularly valuable, because it is the most widely-observed ``heavy-s'' species (Z > 40) in PNe. Its abundance relative to lighter n-capture elements can be used to determine s-process neutron exposures, and constrain s-process enrichment patterns as a function of progenitor metallicity. Using the atomic structure code AUTOSTRUCTURE (Badnell 2011, Comp. Phys. Comm., 182, 1528), we have computed multi-configuration Breit-Pauli distorted-wave PI cross sections and radiative recombination (RR) and dielectronic recombination (DR) rate coefficients for neutral through six-times ionized Xe, data which are critically needed for accurate Xe abundance determinations in ionized nebulae. We find good agreement between our computed direct PI cross sections and experimental measurements. Internal uncertainties are estimated for our calculations by using three different configuration interaction expansions for each ion, and by testing the sensitivity of our results to the radial orbital scaling parameters. As found for other n-capture elements (Sterling & Witthoeft 2011, A&A, 529, A147; Sterling 2011, A&A, 533, A62), DR is the dominant recombination mechanism for Xe ions at nebular temperatures (~104 K). Following Sterling et al. (2015, ApJS, 218, 25), these data will be added to nebular modeling codes to compute ionization correction factors for unobserved Xe ions in PNe, which will enable elemental Xe abundances to be determined with much higher accuracy than is currently possible. This work is supported by NSF award AST-1412928.

  1. LIME silicates in amoeboid olivine aggregates in carbonaceous chondrites: Indicator of nebular and asteroidal processes

    NASA Astrophysics Data System (ADS)

    Komatsu, Mutsumi; Fagan, Timothy J.; Mikouchi, Takashi; Petaev, Michail I.; Zolensky, Michael E.

    2015-07-01

    MnO/FeO ratios in olivine from amoeboid olivine aggregates (AOAs) reflect conditions of nebular condensation and can be used in concert with matrix textures to compare metamorphic conditions in carbonaceous chondrites. LIME (low-iron, Mn-enriched) olivine was identified in AOAs from Y-81020 (CO3.05), Kaba (CV~3.1), and in Y-86009 (CV3), Y-86751 (CV3), NWA 1152 (CR/CV3), but was not identified in AOAs from Efremovka (CV3.1-3.4) or Allende (CV>3.6). According to thermodynamic models of nebular condensation, LIME olivine is stable at lower temperatures than Mn-poor olivine and at low oxygen fugacities (dust enrichment <10× solar). Although this set of samples does not represent a single metamorphic sequence, the higher subtypes tend to have AOA olivine with lower Mn/Fe, suggesting that Mn/Fe decreases during parent body metamorphism. Y-81020 has the lowest subtype and most forsteritic AOA olivine (Fo>95) in our study, whereas Efremovka AOAs are slightly Fe-rich (Fo>92). AOA olivines from Kaba are mostly forsteritic, but rare Fe-rich olivine precipitated from an aqueous fluid. A combination of precipitation of Fe-rich olivine and diffusion of Fe into primary olivine grains resulted in iron-rich compositions (Fo97-59) in Allende AOAs. Variations from fine-grained, nonporous matrix toward higher porosity and coarser lath-like matrix olivine can be divided into six stages represented by (1) Y-81020, Efremovka, NWA 1152; (2) Y-86751 lithology B; (3) Y-86009; (4) Kaba; (5) Y-86751 lithology A; (6) Allende. These stages are inferred to represent general degree of metamorphism, although the specific roles of thermally driven grain growth and diffusion versus aqueous dissolution and precipitation remain uncertain.

  2. Investigating the Possible Anomaly between Nebular and Stellar Oxygen Abundances in the Dwarf Irregular Galaxy WLM

    NASA Astrophysics Data System (ADS)

    Lee, Henry; Skillman, Evan D.; Venn, Kim A.

    2005-02-01

    We obtained new optical spectra of 13 H II regions in WLM with EFOSC2; oxygen abundances are derived for nine H II regions. The temperature-sensitive [O III] λ4363 emission line was measured in two bright H II regions, HM 7 and HM 9. The direct oxygen abundances for HM 7 and HM 9 are 12+log(O/H)=7.72+/-0.04 and 7.91+/-0.04, respectively. We adopt a mean oxygen abundance of 12+log(O/H)=7.83+/-0.06. This corresponds to [O/H]=-0.83 dex, or 15% of the solar value. In H II regions where [O III] λ4363 was not measured, oxygen abundances derived with bright-line methods are in general agreement with direct values of the oxygen abundance to an accuracy of about 0.2 dex. In general, the present measurements show that the H II region oxygen abundances agree with previous values in the literature. The nebular oxygen abundances are marginally consistent with the mean stellar magnesium abundance ([Mg/H]=-0.62). However, there is still a 0.62 dex discrepancy in oxygen abundance between the nebular result and the A-type supergiant star WLM 15 ([O/H]=-0.21). Nonzero reddening values derived from Balmer line ratios were found in H II regions near a second H I peak. There may be a connection between the location of the second H I peak, regions of higher extinction, and the position of WLM 15 on the eastern side of the galaxy. Based on EFOSC2 observations collected at the European Southern Observatory, Chile; proposal No. 71.D-0491(B).

  3. Nebular and auroral emission lines of [Cl III] in the optical spectra of planetary nebulae.

    PubMed

    Keenan, F P; Aller, L H; Ramsbottom, C A; Bell, K L; Crawford, F L; Hyung, S

    2000-04-25

    Electron impact excitation rates in Cl III, recently determined with the R-matrix code, are used to calculate electron temperature (T(e)) and density (N(e)) emission line ratios involving both the nebular (5517.7, 5537.9 A) and auroral (8433.9, 8480.9, 8500.0 A) transitions. A comparison of these results with observational data for a sample of planetary nebulae, obtained with the Hamilton Echelle Spectrograph on the 3-m Shane Telescope, reveals that the R(1) = I(5518 A)/I(5538 A) intensity ratio provides estimates of N(e) in excellent agreement with the values derived from other line ratios in the echelle spectra. This agreement indicates that R(1) is a reliable density diagnostic for planetary nebulae, and it also provides observational support for the accuracy of the atomic data adopted in the line ratio calculations. However the [Cl iii] 8433.9 A line is found to be frequently blended with a weak telluric emission feature, although in those instances when the [Cl iii] intensity may be reliably measured, it provides accurate determinations of T(e) when ratioed against the sum of the 5518 and 5538 A line fluxes. Similarly, the 8500.0 A line, previously believed to be free of contamination by the Earth's atmosphere, is also shown to be generally blended with a weak telluric emission feature. The [Cl iii] transition at 8480.9 A is found to be blended with the He i 8480.7 A line, except in planetary nebulae that show a relatively weak He i spectrum, where it also provides reliable estimates of T(e) when ratioed against the nebular lines. Finally, the diagnostic potential of the near-UV [Cl iii] lines at 3344 and 3354 A is briefly discussed.

  4. Nebular and auroral emission lines of [Cl iii] in the optical spectra of planetary nebulae

    PubMed Central

    Keenan, Francis P.; Aller, Lawrence H.; Ramsbottom, Catherine A.; Bell, Kenneth L.; Crawford, Fergal L.; Hyung, Siek

    2000-01-01

    Electron impact excitation rates in Cl III, recently determined with the R-matrix code, are used to calculate electron temperature (Te) and density (Ne) emission line ratios involving both the nebular (5517.7, 5537.9 Å) and auroral (8433.9, 8480.9, 8500.0 Å) transitions. A comparison of these results with observational data for a sample of planetary nebulae, obtained with the Hamilton Echelle Spectrograph on the 3-m Shane Telescope, reveals that the R1 = I(5518 Å)/I(5538 Å) intensity ratio provides estimates of Ne in excellent agreement with the values derived from other line ratios in the echelle spectra. This agreement indicates that R1 is a reliable density diagnostic for planetary nebulae, and it also provides observational support for the accuracy of the atomic data adopted in the line ratio calculations. However the [Cl iii] 8433.9 Å line is found to be frequently blended with a weak telluric emission feature, although in those instances when the [Cl iii] intensity may be reliably measured, it provides accurate determinations of Te when ratioed against the sum of the 5518 and 5538 Å line fluxes. Similarly, the 8500.0 Å line, previously believed to be free of contamination by the Earth's atmosphere, is also shown to be generally blended with a weak telluric emission feature. The [Cl iii] transition at 8480.9 Å is found to be blended with the He i 8480.7 Å line, except in planetary nebulae that show a relatively weak He i spectrum, where it also provides reliable estimates of Te when ratioed against the nebular lines. Finally, the diagnostic potential of the near-UV [Cl iii] lines at 3344 and 3354 Å is briefly discussed. PMID:10759562

  5. Pure-tone Audiometer

    NASA Astrophysics Data System (ADS)

    Kapul, A. A.; Zubova, E. I.; Torgaev, S. N.; Drobchik, V. V.

    2017-08-01

    The research focuses on a pure-tone audiometer designing. The relevance of the study is proved by high incidence of an auditory analyser in older people and children. At first, the article provides information about subjective and objective audiometry methods. Secondly, we offer block-diagram and basic-circuit arrangement of device. We decided to base on STM32F407VG microcontroller and use digital pot in the function of attenuator. Third, we implemented microcontroller and PC connection. C programming language is used for microcontroller’s program and PC’s interface. Fourthly, we created the pure-tone audiometer prototype. In the future, we will implement the objective method ASSR in addition to pure-tone audiometry.

  6. Dahlbeck and Pure Ontology

    ERIC Educational Resources Information Center

    Mackenzie, Jim

    2016-01-01

    This article responds to Johan Dahlbeck's "Towards a pure ontology: Children's bodies and morality" ["Educational Philosophy and Theory," vol. 46 (1), 2014, pp. 8-23 (EJ1026561)]. His arguments from Nietzsche and Spinoza do not carry the weight he supposes, and the conclusions he draws from them about pedagogy would be…

  7. Dahlbeck and Pure Ontology

    ERIC Educational Resources Information Center

    Mackenzie, Jim

    2016-01-01

    This article responds to Johan Dahlbeck's "Towards a pure ontology: Children's bodies and morality" ["Educational Philosophy and Theory," vol. 46 (1), 2014, pp. 8-23 (EJ1026561)]. His arguments from Nietzsche and Spinoza do not carry the weight he supposes, and the conclusions he draws from them about pedagogy would be…

  8. Language as Pure Potential

    ERIC Educational Resources Information Center

    Park, Joseph Sung-Yul

    2016-01-01

    Language occupies a crucial position in neoliberalism, due to the reimagination of language as commodified skill. This paper studies the role of language ideology in this transformation by identifying a particular ideology that facilitates this process, namely the ideology which views language as pure potential. Neoliberalism treats language as a…

  9. Production of pure metals

    NASA Technical Reports Server (NTRS)

    Philipp, W. H.; Marsik, S. J.; May, C. E. (Inventor)

    1974-01-01

    A process for depositing elements by irradiating liquids is reported. Ultra pure elements are precipitated from aqueous solutions or suspensions of compounds. A solution of a salt of a metal to be prepared is irradiated, and the insoluble reaction product settles out. Some chemical compounds may also be prepared in this manner.

  10. Language as Pure Potential

    ERIC Educational Resources Information Center

    Park, Joseph Sung-Yul

    2016-01-01

    Language occupies a crucial position in neoliberalism, due to the reimagination of language as commodified skill. This paper studies the role of language ideology in this transformation by identifying a particular ideology that facilitates this process, namely the ideology which views language as pure potential. Neoliberalism treats language as a…

  11. Properties of z ~ 3-6 Lyman break galaxies. II. Impact of nebular emission at high redshift

    NASA Astrophysics Data System (ADS)

    de Barros, S.; Schaerer, D.; Stark, D. P.

    2014-03-01

    Context. To gain insight on the mass assembly and place constraints on the star formation history (SFH) of Lyman break galaxies (LBGs), it is important to accurately determine their properties. Aims: We estimate how nebular emission and different SFHs affect parameter estimation of LBGs. Methods: We present a homogeneous, detailed analysis of the spectral energy distribution (SED) of ~1700 LBGs from the GOODS-MUSIC catalogue with deep multi-wavelength photometry from the U band to 8 μm to determine stellar mass, age, dust attenuation, and star formation rate. Using our SED fitting tool, which takes into account nebular emission, we explore a wide parameter space. We also explore a set of different star formation histories. Results: Nebular emission is found to significantly affect the determination of the physical parameters for the majority of z ~ 3-6 LBGs. We identify two populations of galaxies by determining the importance of the contribution of emission lines to broadband fluxes. We find that ~65% of LBGs show detectable signs of emission lines, whereas ~35% show weak or no emission lines. This distribution is found over the entire redshift range. We interpret these groups as actively star-forming and more quiescent LBGs, respectively. We find that it is necessary to considerer SED fits with very young ages (<50 Myr) to reproduce some colours affected by strong emission lines. Other arguments favouring episodic star formation and relatively short star formation timescales are also discussed. Considering nebular emission generally leads to a younger age, lower stellar mass, higher dust attenuation, higher star formation rate, and a large scatter in the SFR-M⋆ relation. Our analysis yields a trend of increasing specific star formation rate with redshift, as predicted by recent galaxy evolution models. Conclusions: The physical parameters of approximately two thirds of high redshift galaxies are significantly modified when we account for nebular emission. The

  12. Constraining the Type Ia Supernova Progenitor: The Search for Hydrogen in Nebular Spectra

    NASA Astrophysics Data System (ADS)

    Leonard, Douglas C.

    2007-12-01

    Despite intense scrutiny, the progenitor system(s) that gives rise to Type Ia supernovae remains unknown. The favored theory invokes a carbon-oxygen white dwarf accreting hydrogen-rich material from a close companion until a thermonuclear runaway ensues that incinerates the white dwarf. However, simulations resulting from this single-degenerate, binary channel demand the presence of low-velocity Hα emission in spectra taken during the late nebular phase, since a portion of the companion's envelope becomes entrained in the ejecta. This hydrogen has never been detected, but has only rarely been sought. Here we present results from a campaign to obtain deep, nebular-phase spectroscopy of nearby Type Ia supernovae, and include multiepoch observations of two events: SN 2005am (slightly subluminous) and SN 2005cf (normally bright). No Hα emission is detected in the spectra of either object. An upper limit of 0.01 Msolar of solar abundance material in the ejecta is established from the models of Mattila et al., which, when coupled with the mass-stripping simulations of Marietta et al. and Meng et al., effectively rules out progenitor systems for these supernovae with secondaries close enough to the white dwarf to be experiencing Roche lobe overflow at the time of explosion. Alternative explanations for the absence of Hα emission, along with suggestions for future investigations necessary to confidently exclude them as possibilities, are critically evaluated. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Additional observations were obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a

  13. Non-nebular Origin of Dark Mantles Around Chondrules and Inclusions in CM Chondrites

    NASA Technical Reports Server (NTRS)

    Trigo-Rodriquez, Josep M.; Rubin, Alan E.; Wasson, John T.

    2006-01-01

    Our examination of nine CM chondrites that span the aqueous alteration sequence leads us to conclude that compact dark fine mantles surrounding chondrules and inclusions in CM chondrites are not discrete fine-grained rims acquired in the solar nebula as modeled by Metzler et al. [Accretionary dust mantles in CM chondrites: evidence for solar nebula processes. Geochim. Cosmochim. Acta 56, 1992, 2873-28971. Nebular processes that lead to agglomeration produce materials with porosities far higher than those in the dark mantles. We infer that the mantles were produced from porous nebular materials on the CM parent asteroid by impact-compaction (a process that produces the lowest porosity adjacent to chondrules and inclusions). Compaction was followed by aqueous alteration that formed tochilinite, serpentine, Ni-bearing sulfide, and other secondary products in voids in the interchondrule regions. Metzler et al. reported a correlation between mantle thickness and the radius of the enclosed object. In Yamato 791 198 we find no correlation when all sizes of central objects and dark lumps are included but a significant correlation (r(sup 2) = 0.44) if we limit consideration to central objects with radii >35 microns; a moderate correlation is also found in QUE 97990. We suggest that impact-induced shear of a plum-pudding-like precursor produced the observed "mantles"; these were shielded from comminution during impact events by the adjacent stronger chondrules and inclusions. Some mantles in CM chondrites with low degrees of alteration show distinct layers that may largely reflect differences in porosity. Typically, a gray, uniform inner layer is surrounded by an outer layer consisting of darker silicates with BSE-bright speckles. The CM-chondrite objects characterized as "primary accretionary rocks" by Metzler et al. did not form in the nebula, but rather on the parent body. The absence of solar-flare particle tracks and solar-wind-implanted rare gases in these clasts

  14. Non-nebular Origin of Dark Mantles Around Chondrules and Inclusions in CM Chondrites

    NASA Technical Reports Server (NTRS)

    Trigo-Rodriquez, Josep M.; Rubin, Alan E.; Wasson, John T.

    2006-01-01

    Our examination of nine CM chondrites that span the aqueous alteration sequence leads us to conclude that compact dark fine mantles surrounding chondrules and inclusions in CM chondrites are not discrete fine-grained rims acquired in the solar nebula as modeled by Metzler et al. [Accretionary dust mantles in CM chondrites: evidence for solar nebula processes. Geochim. Cosmochim. Acta 56, 1992, 2873-28971. Nebular processes that lead to agglomeration produce materials with porosities far higher than those in the dark mantles. We infer that the mantles were produced from porous nebular materials on the CM parent asteroid by impact-compaction (a process that produces the lowest porosity adjacent to chondrules and inclusions). Compaction was followed by aqueous alteration that formed tochilinite, serpentine, Ni-bearing sulfide, and other secondary products in voids in the interchondrule regions. Metzler et al. reported a correlation between mantle thickness and the radius of the enclosed object. In Yamato 791 198 we find no correlation when all sizes of central objects and dark lumps are included but a significant correlation (r(sup 2) = 0.44) if we limit consideration to central objects with radii >35 microns; a moderate correlation is also found in QUE 97990. We suggest that impact-induced shear of a plum-pudding-like precursor produced the observed "mantles"; these were shielded from comminution during impact events by the adjacent stronger chondrules and inclusions. Some mantles in CM chondrites with low degrees of alteration show distinct layers that may largely reflect differences in porosity. Typically, a gray, uniform inner layer is surrounded by an outer layer consisting of darker silicates with BSE-bright speckles. The CM-chondrite objects characterized as "primary accretionary rocks" by Metzler et al. did not form in the nebula, but rather on the parent body. The absence of solar-flare particle tracks and solar-wind-implanted rare gases in these clasts

  15. Purely Cortical Anaplastic Ependymoma

    PubMed Central

    Romero, Flávio Ramalho; Zanini, Marco Antônio; Ducati, Luis Gustavo; Vital, Roberto Bezerra; de Lima Neto, Newton Moreira; Gabarra, Roberto Colichio

    2012-01-01

    Ependymomas are glial tumors derived from ependymal cells lining the ventricles and the central canal of the spinal cord. It may occur outside the ventricular structures, representing the extraventicular form, or without any relationship of ventricular system, called ectopic ependymona. Less than fifteen cases of ectopic ependymomas were reported and less than five were anaplastic. We report a rare case of pure cortical ectopic anaplastic ependymoma. PMID:23119204

  16. Behind the Curtain: Revealing the Nebular Influence on X-ray Emission from Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Montez, Rodolfo, Jr.

    2017-01-01

    Planetary Nebulae (PNe), the ionized shells of gas surrounding dying low- to intermediate-mass stars, are interesting astrophysical plasma laboratories because of the range of plasma conditions that exist in close proximity. Early in the lifetime of PNe, a 106 K plasma---called a hot bubble---fills the 104 K nebular shell. The interaction of these two plasmas is the potential origin of cooler than expected hot bubble temperatures. Studying high-spatial resolution imaging by the Hubble Space Telescope and the Chandra X-ray Observatory offer an opportunity to study the interaction of these two plasmas. Yet the Chandra and HST observations of PN BD+30°3639 indicate distinct X-ray and optical morphologies that do not appear directly correlated. However, we have developed a method that uses Chandra imaging spectroscopy to study the spatial distribution of the hot bubble X-ray emission. Remarkably, applying this method to the X-ray observation reveals the influence of the surrounding nebula and mimics the optical morphology that is otherwise hidden in the X-ray images. We present the methodology, images derived using the method, and the distribution of the physical conditions that likely give rise to the observed effect. Further improvement of the method and establishing its limitations in the low-count regime will help establish the utility of this method for other low-count extended X-ray sources.

  17. Does Oxygen Isotopic Heterogeneity in Refractory Inclusions and Their Wark-Lovering Rims Record Nebular Repressing?

    NASA Technical Reports Server (NTRS)

    Simon, J. I.; Matzel, J. E. P.; Simon, S. B.; Weber, P. K.; Grossman, L.; Ross, D. K.; Hutcheon, I. D.

    2013-01-01

    Large systematic variations in O-isotopic compositions found within individual mineral layers of rims surrounding Ca-, Al-rich inclusions (CAIs) and at the margins of some CAIs imply formation from distinct environments [e.g., 1-3]. The O-isotope compositions of many CAIs preserve a record of the Solar nebula gas believed to initially be O-16-rich (delta O-17 less than or equal to -25%0) [4-5]. Data from a recent study of the compact Type A Allende CAI, A37, preserve a diffusion profile in the outermost 70 micrometers of the inclusion and show greater than 25%0 variations in delta O-17 within its 100 micrometer-thick Wark-Lovering rim (WL-rim) [3]. This and comparable heterogeneity measured in several other CAIs have been explained by isotopic mixing between the O-16-rich Solar reservoir and a second O-16-poor reservoir (probably nebular gas) with a planetary-like isotopic composition, e.g., [1,2,3,6]. However, there is mineralogical and isotopic evidence from the interiors of CAIs, in particular those from Allende, for parent body alteration. At issue is how to distinguish the record of secondary reprocessing in the nebula from that which occurred on the parent body. We have undertaken the task to study a range of CAI types with varying mineralogies, in part, to address this problem.

  18. The nebular emission of star-forming galaxies in a hierarchical universe

    NASA Astrophysics Data System (ADS)

    Orsi, Álvaro; Padilla, Nelson; Groves, Brent; Cora, Sofía; Tecce, Tomás; Gargiulo, Ignacio; Ruiz, Andrés

    2014-09-01

    Galaxy surveys targeting emission lines are characterizing the evolution of star-forming galaxies, but there is still little theoretical progress in modelling their physical properties. We predict nebular emission from star-forming galaxies within a cosmological galaxy formation model. Emission lines are computed by combining the semi-analytical model SAG with the photoionization code MAPPINGS-III. We characterize the interstellar medium of galaxies by relating the ionization parameter of gas in galaxies to their cold gas metallicity, obtaining a reasonable agreement with the observed Hα, [O II] λ 3727, [O III] λ 5007 luminosity functions, and the BPT diagram for local star-forming galaxies. The average ionization parameter is found to increase towards low star formation rates and high redshifts, consistent with recent observational results. The predicted link between different emission lines and their associated star formation rates is studied by presenting scaling relations to relate them. Our model predicts that emission-line galaxies have modest clustering bias, and thus reside in dark matter haloes of masses below Mhalo ≲ 1012 [h-1 M⊙]. Finally, we exploit our modelling technique to predict galaxy number counts up to z ˜ 10 by targeting far-infrared emission lines detectable with submillimetre facilities.

  19. THE KINEMATICS OF THE NEBULAR SHELLS AROUND LOW MASS PROGENITORS OF PNe WITH LOW METALLICITY

    SciTech Connect

    Pereyra, Margarita; López, José Alberto; Richer, Michael G. E-mail: jal@astrosen.unam.mx

    2016-03-15

    We analyze the internal kinematics of 26 planetary nebulae (PNe) with low metallicity that appear to derive from progenitor stars of the lowest masses, including the halo PN population. Based upon spatially resolved, long-slit, echelle spectroscopy drawn from the San Pedro Mártir Kinematic Catalog of PNe, we characterize the kinematics of these PNe measuring their global expansion velocities based upon the largest sample used to date for this purpose. We find kinematics that follow the trends observed and predicted in other studies, but also find that most of the PNe studied here tend to have expansion velocities less than 20 km s{sup −1} in all of the emission lines considered. The low expansion velocities that we observe in this sample of low metallicity PNe with low mass progenitors are most likely a consequence of a weak central star (CS) wind driving the kinematics of the nebular shell. This study complements previous results that link the expansion velocities of the PN shells with the characteristics of the CS.

  20. The Kinematics of the Nebular Shells Around Low Mass Progenitors of PNe with Low Metallicity

    NASA Astrophysics Data System (ADS)

    Pereyra, Margarita; López, José Alberto; Richer, Michael G.

    2016-03-01

    We analyze the internal kinematics of 26 planetary nebulae (PNe) with low metallicity that appear to derive from progenitor stars of the lowest masses, including the halo PN population. Based upon spatially resolved, long-slit, echelle spectroscopy drawn from the San Pedro Mártir Kinematic Catalog of PNe, we characterize the kinematics of these PNe measuring their global expansion velocities based upon the largest sample used to date for this purpose. We find kinematics that follow the trends observed and predicted in other studies, but also find that most of the PNe studied here tend to have expansion velocities less than 20 km s-1 in all of the emission lines considered. The low expansion velocities that we observe in this sample of low metallicity PNe with low mass progenitors are most likely a consequence of a weak central star (CS) wind driving the kinematics of the nebular shell. This study complements previous results that link the expansion velocities of the PN shells with the characteristics of the CS. The observations reported herein were acquired at the Observatorio Astronómico Nacional in the Sierra San Pedro Mártir (OAN-SPM), B. C., Mexico.

  1. Isotopic Investigations of Nebular and Parent Body Processes with a High Sensitivity Ion Microprobe

    NASA Technical Reports Server (NTRS)

    McKeegan, Kevin D.

    2005-01-01

    systematics by a combined approach of high-precision multiple-collector SIMS analyses, traditional analyses on the UCLA ims 1270, and high-spatial resolution analyses using a NanoSIMS instrument. The data help to deconvolve effects due to partial resetting of the A1-Mg system by multiple thermal events. Finally, we initiated investigations related to nebular heterogeneity with a new initiative of in situ high-precision sulfur isotope analyses of sulfides from a wide variety of components of chondrites. The ultimate goal of all this work is to help develop a better understanding of the relationships between CAIs and chondrules, the astrophysical environments in which they formed, and the timescales of nebular processes. As detailed in Table 1, for the project period, 14 manuscripts were published and 17 abstracts were presented describing the work.

  2. The peculiar type II supernova 1993J in M81: Transition to the nebular phase

    NASA Technical Reports Server (NTRS)

    Filippenko, Alexei V.; Matheson, Thomas; Barth, Aaron J.

    1994-01-01

    We present optical spectra of the bright, peculiar Type II supernova 1993J in M81 spanning the first 14 months of its existence, revealing its transition to the nebular phase. Unlike the case in normal Type II supernovae, during the first 2-10 months the H-alpha emission line gradually becomes less prominent relative to other features such as (O I) lambda lambda 6300, 6364 and (Ca II) lambda lambda 7291, 7324, as we had predicted based on early-time (tau less than or approximately equal to 2 months) spectra. The nebular spectrum resembles those of the Type Ib/Ic supernovae 1985F and 1987M, although weak H-alpha emission is easily visible even at late times in SN 1993J. At tau = 8 months a close similarity is found with the spectrum of SN 1987K, the only other Type II supernova known to have undergone such a metamorphosis. The emission lines are considerably broader than those of normal Type II supernovae at comparable phases, consistent with the progenitor having lost a majority of its hydrogen envelope prior to exploding. Consequently, there is now little doubt that Type Ib, and probably Type Ic, supernovae result from core collapse in stripped, massive stars; models of the chemical evolution of galaxies in which these subtypes are ascribed to exploding white dwarfs must be appropriately modified. Although all of the emission lines in spectra of SN 1993J fade roughly exponentially for a considerable time, the fading of H-alpha begins to slow down at tau approximately = 8 months, and in the interval tau = 10-14 months its flux is constant, or even slightly rising in the wings of the line. This behavior, together with the box-like shape and great breadth (full width at half maximum (FWHM) approximately = 17 000 km/s) of the line profile, suggests that the H-alpha emission is being produced by the high-velocity outer layer of hydrogen ejecta interacting with circumstellar gas released by the progenitor prior to its explosion. A similar phenomenon has previously been

  3. Diffuse gas in retired galaxies: nebular emission templates and constraints on the sources of ionization

    NASA Astrophysics Data System (ADS)

    Johansson, Jonas; Woods, Tyrone E.; Gilfanov, Marat; Sarzi, Marc; Chen, Yan-Mei; Oh, Kyuseok

    2016-10-01

    We present emission-line templates for passively-evolving (`retired') galaxies, useful for investigation of the evolution of the interstellar medium in these galaxies, and characterization of their high-temperature source populations. The templates are based on high signal-to-noise (>800) co-added spectra (3700-6800 Å) of ˜11 500 gas-rich Sloan Digital Sky Survey galaxies devoid of star formation and active galactic nuclei. Stacked spectra are provided for the entire sample and sub-samples binned by mean stellar age. In our previous paper, Johansson et al., these spectra provided the first measurements of the He II 4686 Å line in passively-evolving galaxies, and the observed He II/Hβ ratio constrained the contribution of accreting white dwarfs (the `single-degenerate' scenario) to the Type Ia supernova rate. In this paper, the full range of unambiguously detected emission lines are presented. Comparison of the observed [O I] 6300 Å/Hα ratio with photoionization models further constrains any high-temperature single-degenerate scenario for Type Ia supernovae (with 1.5 ≲ T/105 K ≲ 10) to ≲3-6 per cent of the observed rate in the youngest age bin (i.e. highest SN Ia rate). Hence, for the same temperatures, in the presence of an ambient population of post-asymptotic giant branch stars, we exclude additional high-temperature sources with a combined ionizing luminosity of ≈1.35 × 1030 L⊙/M⊙,* for stellar populations with mean ages of 1-4 Gyr. Furthermore, we investigate the extinction affecting both the stellar and nebular continuum. The latter shows about five times higher values. This contradicts isotropically distributed dust and gas that renders similar extinction values for both cases.

  4. The multifaceted Type II-L supernova 2014G from pre-maximum to nebular phase

    NASA Astrophysics Data System (ADS)

    Terreran, G.; Jerkstrand, A.; Benetti, S.; Smartt, S. J.; Ochner, P.; Tomasella, L.; Howell, D. A.; Morales-Garoffolo, A.; Harutyunyan, A.; Kankare, E.; Arcavi, I.; Cappellaro, E.; Elias-Rosa, N.; Hosseinzadeh, G.; Kangas, T.; Pastorello, A.; Tartaglia, L.; Turatto, M.; Valenti, S.; Wiggins, P.; Yuan, F.

    2016-10-01

    We present multiband ultraviolet, optical, and near-infrared photometry, along with visual-wavelength spectroscopy, of supernova (SN) 2014G in the nearby galaxy NGC 3448 (25 Mpc). The early-phase spectra show strong emission lines of the high ionization species He II/N IV/C IV during the first 2-3 d after explosion, traces of a metal-rich circumstellar material (CSM) probably due to pre-explosion mass-loss events. These disappear by day 9 and the spectral evolution then continues matching that of normal Type II SNe. The post-maximum light curve declines at a rate typical of Type II-L class. The extensive photometric coverage tracks the drop from the photospheric stage and constrains the radioactive tail, with a steeper decline rate than that expected from the 56Co decay if γ-rays are fully trapped by the ejecta. We report the appearance of an unusual feature on the blue side of H α after 100 d, which evolves to appear as a flat spectral feature linking H α and the [O I] doublet. This may be due to interaction of the ejecta with a strongly asymmetric, and possibly bipolar CSM. Finally, we report two deep spectra at ˜190 and 340 d after explosion, the latter being arguably one of the latest spectra for a Type II-L SN. By modelling the spectral region around the [Ca II], we find a supersolar Ni/Fe production. The strength of the [O I] λλ6300,6363 doublet, compared with synthetic nebular spectra, suggests a progenitor with a zero-age main-sequence mass between 15 and 19 M⊙.

  5. ALH85085: a unique volatile-poor carbonaceous chondrite with possible implications for nebular fractionation processes

    USGS Publications Warehouse

    Grossman, J.N.; Rubin, A.E.; MacPherson, G.J.

    1988-01-01

    Allan Hills 85085 is a unique chondrite with affinities to the Al Rais-Renazzo clan of carbonaceous chondrites. Its constituents are less than 50 ??m in mean size. Chondrules and microchondrules of all textures are present; nonporphyritic chondrules are unusually abundant. The mean compositions of porphyritic, nonporphyritic and barred olivine chondrules resemble those in ordinary chondrites except that they are depleted in volatile elements. Ca-, Al-rich inclusions are abundant and largely free of nebular alteration; they comprise types similar to those in CM and CO chondrites, as well as unique types. Calcium dialuminate occurs in several inclusions. Metal, silicate and sulfide compositions are close to those in CM-CO chondrites and Al Rais and Renazzo. C1-chondrite clasts and metal-rich "reduced" clasts are present, but opaque matrix is absent. Siderophile abundances in ALH85085 are extremely high (e.g., Fe Si = 1.7 ?? solar), and volatiles are depleted (e.g., Na Si = 0.25 ?? solar, S Si = 0.03 ?? solar). Nonvolatile lithophile abundances are similar to those in Al Rais, Renazzo, and CM and CO chondrites. ALH85085 agglomerated when temperatures in the nebula were near 1000 K, in the same region where Renazzo, Al Rais and the CI chondrites formed. Agglomeration of high-temperature material may thus be a mechanism by which the fractionation of refractory lithophiles occurred in the nebula. Chondrule formation must have occurred at high temperatures when clumps of precursors were small. After agglomeration, ALH85085 was annealed and lightly shocked. C1 and other clasts were subsequently incorporated during late-stage brecciation. ?? 1988.

  6. THE EVOLUTION OF THE KINEMATICS OF NEBULAR SHELLS IN PLANETARY NEBULAE IN THE MILKY WAY BULGE

    SciTech Connect

    Richer, Michael G.; Lopez, Jose Alberto; Garcia-Diaz, Maria Teresa; Clark, David M.; Pereyra, Margarita; Diaz-Mendez, Enrique E-mail: jal@astrosen.unam.m E-mail: dmclark@astrosen.unam.m E-mail: e.d.mendez@tcu.ed

    2010-06-10

    We study the line widths in the [O III]{lambda}5007 and H{alpha} lines for two groups of planetary nebulae in the Milky Way bulge based upon spectroscopy obtained at the Observatorio Astronomico Nacional in the Sierra San Pedro Martir (OAN-SPM) using the Manchester Echelle Spectrograph. The first sample includes objects early in their evolution, having high H{beta} luminosities, but [O III]{lambda}5007/H{beta} < 3. The second sample comprises objects late in their evolution, with He II {lambda}4686/H{beta}>0.5. These planetary nebulae represent evolutionary phases preceding and following those of the objects studied by Richer et al. in 2008. Our sample of planetary nebulae with weak [O III]{lambda}5007 has a line width distribution similar to that of the expansion velocities of the envelopes of asymptotic giant branch stars and shifted to systematically lower values as compared to the less evolved objects studied by Richer et al. The sample with strong He II {lambda}4686 has a line width distribution indistinguishable from that of the more evolved objects from Richer et al., but a distribution in angular size that is systematically larger and so they are clearly more evolved. These data and those of Richer et al. form a homogeneous sample from a single Galactic population of planetary nebulae, from the earliest evolutionary stages until the cessation of nuclear burning in the central star. They confirm the long-standing predictions of hydrodynamical models of planetary nebulae, where the kinematics of the nebular shell are driven by the evolution of the central star.

  7. Isotopic diversity in nebular dust: The distribution of Ti isotopic anomalies in carbonaceous chondrites

    SciTech Connect

    Niemeyer, S. )

    1988-12-01

    Average Ti isotopic patterns are derived for each class of carbonaceous chondrite from a chemically characterized suite of whole-rock samples. There is a well-resolved excess of {sup 50}Ti in a subset of CI meteorites. Mean values of the {sup 50}Ti excess for the four classes span a range of only 2 {epsilon}-units, with an apparent positive correlation with Al content. Previous evidence for anomalies in chondrules is augmented here by demonstrating that: (1) the more pristine Ca-Al-rich inclusions (CAIs) in Efremovka show the same isotopic pattern as the typical Allende CAI; and, (2) CM and CV matrix carry {sup 50}Ti excesses of about 2 {epsilon}-units. The distribution of Ti isotopic anomalies among matrix, chondrules, and CAIs suggests a model in which all three constituents formed from precursor-assemblages in which some chemical memories were still intact; the isotopic differences reflect fractionations among the carrier phases of the different isotopic components. Chondrules formed by a mostly closed-system melting of their precursors, and thus provide a recording of the extent of nebular heterogeneity on the mg-size scale. The larger anomalies in CAIs, compared to matrix and most (but not all) chondrules, are attributed primarily to an open- rather than closed-system processing of the CAI precursors. Precursors of both FUN and normal CAIs experienced an episode of intense processing, perhaps partial melting, that created the FUN characteristics, but for normal CAIs the FUN effects were erased by subsequent isotopic equilibration and exchange.

  8. Pure Intrathoracic Scapular Dislocation.

    PubMed

    Demirkiran, Nihat Demirhan; Kar, Adem

    2016-01-01

    Scapular dislocation, also known as locked scapula or scapulothoracic dislocation, is a rare entity that can be identified as extrathoracic or intrathoracic dislocation, depending on the penetration of the scapula into the thoracic cavity. The 3 reported cases of intrathoracic scapular dislocations in the literature are associated with a preexisting condition, such as sternoclavicular separation, prior rib fracture, thoracotomy for a lung transplant procedure, or surgical resection of superior ribs during breast or pulmonary tumor excisions. There are also 3 published cases of intrathoracic scapular impaction, involving comminuted scapular fractures with intrathoracic impaction of the inferior fragment through intercostal space. We report an intrathoracic scapular dislocation that was not associated with fracture of the scapula or predisposing factors. To our knowledge, this is the first case of pure intrathoracic dislocation.

  9. Pure parsimony xor haplotyping.

    PubMed

    Bonizzoni, Paola; Della Vedova, Gianluca; Dondi, Riccardo; Pirola, Yuri; Rizzi, Romeo

    2010-01-01

    The haplotype resolution from xor-genotype data has been recently formulated as a new model for genetic studies. The xor-genotype data is a cheaply obtainable type of data distinguishing heterozygous from homozygous sites without identifying the homozygous alleles. In this paper, we propose a formulation based on a well-known model used in haplotype inference: pure parsimony. We exhibit exact solutions of the problem by providing polynomial time algorithms for some restricted cases and a fixed-parameter algorithm for the general case. These results are based on some interesting combinatorial properties of a graph representation of the solutions. Furthermore, we show that the problem has a polynomial time k-approximation, where k is the maximum number of xor-genotypes containing a given single nucleotide polymorphisms (SNP). Finally, we propose a heuristic and produce an experimental analysis showing that it scales to real-world large instances taken from the HapMap project.

  10. Pure laparoscopic augmentation ileocystoplasty.

    PubMed

    Rebouças, Rafael B; Monteiro, Rodrigo C; Souza, Thiago N S de; Aragão, Augusto J de; Burity, Camila R T; Nóbrega, Júlio C de A; Oliveira, Natália S C de; Abrantes, Ramon B; Dantas Júnior, Luiz B; Cartaxo Filho, Ricardo; Negromonte, Gustavo R P; Sampaio, Rafael da C R; Britto, Cesar A

    2014-01-01

    Guillain-Barre syndrome is an acute neuropathy that rarely compromises bladder function. Conservative management including clean intermittent catheterization and pharmacotherapy is the primary approach for hypocompliant contracted bladder. Surgical treatment may be used in refractory cases to improve bladder compliance and capacity in order to protect the upper urinary tract. We describe a case of pure laparoscopic augmentation ileocystoplasty in a patient affected by Guillain-Barre syndrome. A 15-year-old female, complaining of voiding dysfunction, recurrent urinary tract infection and worsening renal function for three months. A previous history of Guillain-Barre syndrome on childhood was related. A voiding cystourethrography showed a pine-cone bladder with moderate post-void residual urine. The urodynamic demonstrated a hypocompliant bladder and small bladder capacity (190 mL) with high detrusor pressure (54 cmH2O). Nonsurgical treatments were attempted, however unsuccessfully.

  11. Pure right ventricular infarction.

    PubMed

    Inoue, Katsuji; Matsuoka, Hiroshi; Kawakami, Hideo; Koyama, Yasushi; Nishimura, Kazuhisa; Ito, Taketoshi

    2002-02-01

    A 76-year-old man with chest pain was admitted to hospital where electrocardiography (ECG) showed ST-segment elevation in leads V1-4, indicative of acute anterior myocardial infarction. ST-segment elevation was also present in the right precordial leads V4R-6R. Emergency coronary angiography revealed that the left coronary artery was dominant and did not have significant stenosis. Aortography showed ostial occlusion of the right coronary artery (RCA). Left ventriculography showed normal function and right ventriculography showed a dilated right ventricle and severe hypokinesis of the right ventricular free wall. Conservative treatment was selected because the patient's symptoms soon ameliorated and his hemodynamics was stable. 99mTc-pyrophosphate and 201Tl dual single-photon emission computed tomography showed uptake of 99mTc-pyrophosphate in only the right ventricular free wall, but no uptake of 99mTc-pyrophosphate and no perfusion defect of 201Tl in the left ventricle. The peak creatine kinase (CK) and CK-MB were 1,381 IU/L and 127 IU/L, respectively. His natural course was favorable and the chest pain disappeared under medication. Two months after the onset, the ECG showed poor R progression in leads V1-4 indicating an old anterior infarction. Coronary angiography confirmed the ostial stenosis of the hypoplastic RCA. This was a case of pure right ventricular free wall infarction because of the occlusion of the ostium of the hypoplastic RCA, but not of the right ventricular branch. Because the electrocardiographic findings resemble those of an acute anterior infarction, it is important to consider pure right ventricular infarction in the differential diagnosis.

  12. Nebular gas drag and planetary accretion. II. Planet on an eccentric orbit.

    NASA Astrophysics Data System (ADS)

    Kary, David M.; Lissauer, Jack J.

    1995-09-01

    We study the trajectories of planetesimals whose orbits decay starward as a result of gas drag and are perturbed by the gravity of a massive planet on an eccentric orbit. Each planetesimal ultimately suffers one of three possible fates: (1) trapping in a mean motion resonance with the planet, (2) accretion by the planet, or (3) passage by the planet and continued orbital decay. At moderate to large planetary eccentricity, numerical 3-body integrations of the motion of a planetesimal in the solar nebula demonstrate that migrating planetesimals can become trapped in the 1/1 resonance. These bodies initially have large libration amplitudes (approaching 2π) which decay down to 0 at the trailing Lagrange point. With some combinations of drag rate and planetary eccentricity, over 15% of the planetesimals which encounter the planet are trapped in the 1/1 resonance. Bodies trapped in the this way could be the precursors of the Trojan asteroids. Migrating planetesimals can be caught in both pure Lindblad and combined Lindblad/corotation resonances exterior to the planet's orbit. Trapping has been found in several j/( j + k) resonances with k's ranging from 1 to 4. As one considers larger planetary eccentricities, corotation resonances become more important than Lindblad resonances, and (for a given drag rate) trapping can occur at higher k's and farther from the planet. At large planetary eccentricities, planetesimals can also be caught in ( j + 1)/ j Lindblad/corotation resonances interior to the planet. Interior trapping, which is dynamically forbidden in the case of a planet on a circular orbit, requires planetary eccentricity to increase both the planetesimal's semimajor axis and its eccentricity near conjunction to counter gas drag. Provided the planetesimal's and planet's apoapses are roughly aligned, and conjunction occurs while both bodies are approaching apoapse, then the planetesimal can become trapped in an interior resonance. The probability of a planetesimal

  13. How Do Type Ia Supernova Nebular Spectra Depend on Explosion Properties? Insights from Systematic Non-LTE Modeling

    NASA Astrophysics Data System (ADS)

    Botyánszki, János; Kasen, Daniel

    2017-08-01

    We present a radiative transfer code to model the nebular phase spectra of supernovae (SNe) in non-LTE (NLTE). We apply it to a systematic study of SNe Ia using parameterized 1D models and show how nebular spectral features depend on key physical parameters, such as the time since explosion, total ejecta mass, kinetic energy, radial density profile, and the masses of 56Ni, intermediate-mass elements, and stable iron-group elements. We also quantify the impact of uncertainties in atomic data inputs. We find the following. (1) The main features of SN Ia nebular spectra are relatively insensitive to most physical parameters. Degeneracy among parameters precludes a unique determination of the ejecta properties from spectral fitting. In particular, features can be equally well fit with generic Chandrasekhar mass ({M}{ch}), sub-{M}{Ch}, and super-{M}{Ch} models. (2) A sizable (≳0.1 {M}⊙ ) central region of stable iron-group elements, often claimed as evidence for {M}{Ch} models, is not essential to fit the optical spectra and may produce an unusual flat-top [Co iii] profile. (3) The strength of [S iii] emission near 9500 Å can provide a useful diagnostic of explosion nucleosynthesis. (4) Substantial amounts (≳0.1 {M}⊙ ) of unburned C/O mixed throughout the ejecta produce [O iii] emission not seen in observations. (5) Shifts in the wavelength of line peaks can arise from line-blending effects. (6) The steepness of the ejecta density profile affects the line shapes, offering a constraint on explosion models. (7) Uncertainties in atomic data limit the ability to infer physical parameters.

  14. PURE CULTURES OF CELLS

    PubMed Central

    Carrel, Alexis

    1912-01-01

    In experiment I a group of ameboid cells was isolated from a culture of cardiac muscle sixty-three days old, and cultivated in plasma. After several passages, they formed a dense tissue from which ameboid cells radiated. The culture was divided into two parts. The part cultivated in plasma alone kept its morphological characters and continued to produce ameboid cells. The part cultivated upon silk in plasma became modified; the cells lost their ameboid characters, and were transformed into large elongated cells which were united in chains, or interlaced to form a network. In experiment II the round cells taken from a culture of connective tissue seventy-four days old multiplied rapidly. They transformed themselves into elongated cells and produced, after a few passages, a mass of dense connective tissue. From the tissue a large number of elongated cells were constantly growing. In both experiments the tissues originated from the ameboid or round cells extirpated from cultures that were sixty-three and seventy-four days old respectively. These cultures were still growing actively thirty and forty days later; that is, more than one hundred days after the extirpation of the original fragments from the organism. These experiments show that from old cultures it is possible to isolate and propagate cells that belong to a definite type. A tissue, formed by a pure strain of cells, can be obtained in this way, and this new method may be of value in cytological investigations. PMID:19867562

  15. Multiple Nebular Gas Reservoirs Recorded by Oxygen Isotope Variation in a Spinel-rich CAI in CO3 MIL 090019

    NASA Technical Reports Server (NTRS)

    Simon, J. I.; Simon, S. B.; Nguyen, A. N.; Ross, D. K.; Messenger, S.

    2017-01-01

    We conducted NanoSIMS O-isotopic imaging of a primitive spinel-rich CAI spherule (27-2) from the MIL 090019 CO3 chondrite. Inclusions such as 27-2 are proposed to record inner nebula processes during an epoch of rapid solar nebula evolution. Mineralogical and textural analyses suggest that this CAI formed by high temperature reactions, partial melting, and condensation. This CAI exhibits radial O-isotopic heterogeneity among multiple occurrences of the same mineral, reflecting interactions with distinct nebular O-isotopic reservoirs.

  16. DUST ATTENUATION OF THE NEBULAR REGIONS OF z ∼ 2 STAR-FORMING GALAXIES: INSIGHT FROM UV, IR, AND EMISSION LINES

    SciTech Connect

    De Barros, S.; Reddy, N.; Shivaei, I.

    2016-04-01

    We use a sample of 149 spectroscopically confirmed UV-selected galaxies at z ∼ 2 to investigate the relative dust attenuation of the stellar continuum and the nebular emission lines. For each galaxy in the sample, at least one rest-frame optical emission line (Hα/[N ii] λ6583 or [O iii] λ5007) measurement has been taken from the litterature, and 41 galaxies have additional Spitzer/MIPS 24 μm observations that are used to infer infrared luminosities. We use a spectral energy distribution (SED) fitting code that predicts nebular line strengths when fitting the stellar populations of galaxies in our sample, and we perform comparisons between the predictions of our models and the observed/derived physical quantities. We find that on average our code is able to reproduce all the physical quantities (e.g., UV β slopes, infrared luminosities, emission line fluxes), but we need to apply a higher dust correction to the nebular emission compared to the stellar emission for the largest star formation rate (SFR) (log SFR/M{sub ⊙} yr{sup −1} > 1.82, Salpeter initial mass function). We find a correlation between SFR and the difference in nebular and stellar color excesses, which could resolve the discrepant results regarding nebular dust correction at z ∼ 2 from previous studies.

  17. The MOSDEF Survey: First Measurement of Nebular Oxygen Abundance at z > 4

    NASA Astrophysics Data System (ADS)

    Shapley, Alice E.; Sanders, Ryan L.; Reddy, Naveen A.; Kriek, Mariska; Freeman, William R.; Mobasher, Bahram; Siana, Brian; Coil, Alison L.; Leung, Gene C. K.; deGroot, Laura; Shivaei, Irene; Price, Sedona H.; Azadi, Mojegan; Aird, James

    2017-09-01

    We present the first spectroscopic measurement of multiple rest-frame optical emission lines at z > 4. During the MOSFIRE Deep Evolution Field survey, we observed the galaxy GOODSN-17940 with the Keck I/MOSFIRE spectrograph. The K-band spectrum of GOODSN-17940 includes significant detections of the [O ii]λλ3726,3729, [Ne iii]λ3869, and Hγ emission lines and a tentative detection of Hδ, indicating z spec = 4.4121. GOODSN-17940 is an actively star-forming z > 4 galaxy based on its K-band spectrum and broadband spectral energy distribution. A significant excess relative to the surrounding continuum is present in the Spitzer/IRAC channel 1 photometry of GOODSN-17940, due primarily to strong Hα emission with a rest-frame equivalent width of EW(Hα) = 1200 Å. Based on the assumption of 0.5 Z ⊙ models and the Calzetti attenuation curve, GOODSN-17940 is characterized by {M}* ={5.0}-0.2+4.3× {10}9 {M}ȯ . The Balmer decrement inferred from Hα/Hγ is used to dust correct the Hα emission, yielding {{SFR(H}}α )={320}-140+190 {M}ȯ {{{yr}}}-1. These M * and star formation rate (SFR) values place GOODSN-17940 an order of magnitude in SFR above the z ∼ 4 star-forming “main sequence.” Finally, we use the observed ratio of [Ne iii]/[O ii] to estimate the nebular oxygen abundance in GOODSN-17940, finding O/H ∼ 0.2 (O/H)⊙. Combining our new [Ne iii]/[O ii] measurement with those from stacked spectra at z ∼ 0, 2, and 3, we show that GOODSN-17940 represents an extension to z > 4 of the evolution toward higher [Ne iii]/[O ii] (i.e., lower O/H) at fixed stellar mass. It will be possible to perform the measurements presented here out to z ∼ 10 using the James Webb Space Telescope. Based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and was made possible by the generous financial support

  18. Secondary Mineralization of Components in CV3 Chondrites: Nebular and Asteroidal Models

    NASA Astrophysics Data System (ADS)

    Scott, E. R. D.; Krot, A. N.; Zolensky, M. E.

    1995-09-01

    Our review of mineralogical variations among CV3 chondrites suggests that all components, chondrules, matrices, and CAIs, were affected by various degrees of secondary mineralization. Chondrules and CAIs are rimmed with fayalitic olivine [1, 2]; metal in all components is oxidized and sulfidized to magnetite, Ni-rich metal and sulfides [3]; silicates in all components are aqueously altered to phyllosilicates [4]; and nepheline, sodalite, wollastonite, and hedenbergite replace primary minerals in CAIs [5]. In those CV3s with altered CAIs, nepheline etc. are also present in chondrule mesostases [6] and in matrices [7]. Correlated occurrences of secondary minerals indicate that they have related origins. CV3 chondrites can be divided into three kinds according to their secondary features. Reduced CV3s (e.g., Efremovka) lack magnetite [8] and show minimal secondary features. Oxidized CV3s [8] generally show all features: those like Mokoia contain minor fayalitic rims, nepheline, etc, whereas those like Allende lack phyllosilicates but contain well developed fayalite rims and abundant nepheline, etc. Allende-like CV3 chondrites also contain abundant plate-like matrix olivine (Fa(sub)45-55). Similarities in chemistry and O isotopic composition and petrographic observations suggest that fayalitic rims and plate-like matrix olivine have related origins [1, 9]. The presence of secondary minerals in all components implies that alteration postdated component formation. The absence of secondary minerals in reduced CV3s indicates that CV3 oxidized formed from CV3 reduced-like material. Oxidized and reduced materials coexist in some breccias indicating a common parent asteroid. Nebular origins are widely accepted for most secondary features. To form fayalitic rims and matrix , Palme and colleagues [10, 11] suggest that chondritic components were briefly exposed to a hot (>1500 K), highly oxidizing nebula with H2O/H2 to about 1. Such an environment could have resulted from

  19. Examining the Offset Between Nebular and Stellar Oxygen Abundances in the Local Group Dwarf Irregular Galaxy WLM

    NASA Astrophysics Data System (ADS)

    Skillman, E. D.; Lee, H.; Venn, K. A.

    2004-12-01

    New optical spectra of 13 H II regions in WLM were obtained with the EFOSC2 instrument on the 3.6-m telescope at La Silla. From measurements of the temperature-sensitive [O III]λ 4363 Å emission line, we derive a mean oxygen abundance of 12+log(O/H) = 7.83 ± 0.06, which corresponds to [O/H] = -0.83 dex, or 15% of the solar value. Our reported nebular oxygen abundance agrees with values published in the literature, and is marginally consistent with the mean stellar magnesium abundance [Mg/H] = -0.62. However, there is still a 0.62 dex discrepancy between the oxygen abundance derived for the A-type supergiant star WLM 15 ([O/H] = -0.21) and the nebular value. There may be a connection between the position of WLM 15, the location of a second H I peak, and regions of higher internal extinction on the southeast side of the galaxy. E. D. S. and H. L. acknowledge partial support from a NASA LTSARP grant NAG 5--9221 and from the University of Minnesota. K. A. V. thanks the National Science Foundation for support through a CAREER award AST 99--84073.

  20. A whiff of nebular gas in Titan's atmosphere - Potential implications for the conditions and timing of Titan's formation

    NASA Astrophysics Data System (ADS)

    Glein, Christopher R.

    2017-09-01

    In situ data from the GCMS instrument on the Huygens probe indicate that Titan's atmosphere contains small amounts of the primordial noble gases 36Ar and 22Ne (tentative detection), but it is unknown how they were obtained by the satellite. Based on the apparent similarity in the 22Ne/36Ar (atom) ratio between Titan's atmosphere and the solar composition, a previously neglected hypothesis for the origin of primordial noble gases in Titan's atmosphere is suggested - these species may have been acquired near the end of Titan's formation, when the moon could have gravitationally captured some nebular gas that would have been present in its formation environment (the Saturnian subnebula). These noble gases may be remnants of a primary atmosphere. This could be considered the simplest hypothesis to explain the 22Ne/36Ar ratio observed at Titan. However, the 22Ne/36Ar ratio may not be exactly solar if these species can be fractionated by external photoevaporation in the solar nebula, atmospheric escape from Titan, or sequestration on the surface of Titan. While the GCMS data are consistent with a 22Ne/36Ar ratio of 0.05 to 2.5 times solar (1σ range), simple estimates that attempt to account for some of the effects of these evolutionary processes suggest a sub-solar ratio, which may be depleted by approximately one order of magnitude. Models based on capture of nebular gas can explain why the GCMS did not detect any other primordial noble gas isotopes, as their predicted abundances are below the detection limits (especially for 84Kr and 132Xe). It is also predicted that atmospheric Xe on Titan should be dominated by radiogenic 129Xe if the source of primordial Xe is nebular gas. Of order 10-2-10-1 bar of primordial H2 may have been captured along with the noble gases from a gas-starved disk, but this H2 would have quickly escaped from the initial atmosphere. To have the opportunity to capture nebular gas, Titan should have formed within ∼10 Myr of the formation of the

  1. Large pure intracranial vagal schwannoma.

    PubMed

    Gazzeri, Roberto; Galarza, Marcelo; Costanzo, De Bonis; Carotenuto, Vincenzo; D'Angelo, Vincenzo

    2009-04-01

    We report a patient with a large, pure intracranial vagal schwannoma, compressing the medulla who presented with essential hypertension. Based on this and on previous cases, we suggest that a differentiation of pure intracranial schwannomas (subtype A1) from intracranial schwannomas with some extension in the jugular foramen (type A) should be used.

  2. Defense Mechanisms in "Pure" Anxiety and "Pure" Depressive Disorders.

    PubMed

    Colovic, Olga; Lecic Tosevski, Dusica; Perunicic Mladenovic, Ivana; Milosavljevic, Maja; Munjiza, Ana

    2016-10-01

    Our study was intended to test whether there are any differences in the way defense mechanisms are used by patients suffering from pure anxiety and those with pure depressive disorders. The sample size was as follows: depressive disorders without psychotic symptoms 30, anxiety disorders 30, and the healthy control group 30. The assessment of defense mechanisms was made using the DSQ-40 questionnaire. Our findings show that "pure" anxiety disorders differ from "pure" depressive disorders only in the use of immature defense mechanisms. The group with depressive disorders was significantly more prone to use immature defense mechanisms than the group with anxiety disorders (p = 0.005), primarily projection (p = 0.001) and devaluation (p = 0.003). These defense mechanisms may therefore be used both to differentiate between anxiety and depressive disorders and also to determine which symptoms (anxiety or depressive disorders) are dominant at any given stage of treatment.

  3. Particle Size Distributions Obtained Through Unfolding 2D Sections: Towards Accurate Distributions of Nebular Solids in the Allende Meteorite

    NASA Technical Reports Server (NTRS)

    Christoffersen, P. A.; Simon, Justin I.; Ross, D. K.; Friedrich, J. M.; Cuzzi, J. N.

    2012-01-01

    Size distributions of nebular solids in chondrites suggest an efficient sorting of these early forming objects within the protoplanetary disk. The effect of this sorting has been documented by investigations of modal abundances of CAIs (e.g., [1-4]) and chondrules (e.g., [5-8]). Evidence for aerodynamic sorting in the disk is largely qualitative, and needs to be carefully assessed. It may be a way of concentrating these materials into planetesimal-mass clumps, perhaps 100 fs of ka after they formed. A key parameter is size/density distributions of particles (i.e., chondrules, CAIs, and metal grains), and in particular, whether the radius-density product (rxp) is a better metric for defining the distribution than r alone [9]. There is no consensus between r versus rxp based models. Here we report our initial tests and preliminary results, which when expanded will be used to test the accuracy of current dynamical disk models.

  4. The Carlisle Lakes-type chondrites - A new grouplet with high Delta(17)O and evidence for nebular oxidation

    NASA Technical Reports Server (NTRS)

    Weisberg, Michael K.; Prinz, Martin; Kojima, Hideyasu; Yanai, Keizo; Clayton, Robert N.; Mayeda, Toshiko K.

    1991-01-01

    The petrogenesis of the Carlisle Lakes-type chondrites and their relationship to other chondrites are studied using new petrologic data, especially on mineralogical zoning patterns, and oxygen isotopic analyses of the whole chondrites and some of chondrules. Detailed zoning profiles of mafic silicates are measured in order to determine the environment(s) in which their oxidation states are established. It is concluded that the zoning did not form during crystallization from a melt droplet chondrule but post-dated chondrule formation. Parent-body thermal metamorphism and nebular gas-solid exchange reactions accompanied by condensation of new FeO-rich olivine, utilizing existing olivine surfaces as nucleation sites are considered as hypotheses explaining the zoning. The occurrence of zoned grains in a host that is mainly equilibrated suggests that the equilibration of the Carlisle Lakes-type chondrites occurred prior to final lithification.

  5. Pure autonomic failure without synucleinopathy.

    PubMed

    Isonaka, Risa; Holmes, Courtney; Cook, Glen A; Sullivan, Patti; Sharabi, Yehonatan; Goldstein, David S

    2017-04-01

    Pure autonomic failure is a rare form of chronic autonomic failure manifesting with neurogenic orthostatic hypotension and evidence of sympathetic noradrenergic denervation unaccompanied by signs of central neurodegeneration. It has been proposed that pure autonomic failure is a Lewy body disease characterized by intra-neuronal deposition of the protein alpha-synuclein in Lewy bodies and neurites. A middle-aged man with previously diagnosed pure autonomic failure experienced a sudden, fatal cardiac arrest. He was autopsied, and tissues were harvested for neurochemical and immunofluorescence studies. Post-mortem microscopic neuropathology showed no Lewy bodies, Lewy neurites, or alpha-synuclein deposition by immunohistochemistry anywhere in the brain. The patient had markedly decreased immunofluorescent tyrosine hydroxylase in sympathetic ganglion tissue without detectable alpha-synuclein even in rare residual nests of tyrosine hydroxylase-containing ganglionic fibers. In pure autonomic failure, sympathetic noradrenergic denervation can occur without concurrent Lewy bodies or alpha-synuclein deposition in the brain or sympathetic ganglion tissue.

  6. Nebular line emission from z > 7 galaxies in a cosmological simulation: rest-frame UV to optical lines

    NASA Astrophysics Data System (ADS)

    Shimizu, Ikkoh; Inoue, Akio K.; Okamoto, Takashi; Yoshida, Naoki

    2016-10-01

    We have performed very large and high-resolution cosmological hydrodynamic simulations in order to investigate detectability of nebular lines in the rest-frame ultraviolet (UV) to optical wavelength range from galaxies at z > 7. We find that the expected line fluxes are very well correlated with the apparent UV magnitudes. The C IV 1549 Å and C III] 1909 Å lines of galaxies brighter than 26 AB magnitudes are detectable with current facilities such as the Very Large Telescope (VLT) XShooter and the Keck Multi-Object Spectrometer for Infra-Red Exploration (MOSFIRE). Metal lines such as C IV 1549 Å, C III] 1909 Å, [O II] 3727 Å and [O III] 4959/5007 Å are good targets for spectroscopic observation with the Thirty-Metre Telescope (TMT), European Extremely Large Telescope (E-ELT), Giant Magellan Telescope (GMT) and James Webb Space Telescope (JWST). We also expect Hα and Hβ lines to be detectable with these telescopes. Additionally, we predict the detectability of nebular lines for z > 10 galaxies, which will be found with JWST, the Wide-Field Infrared Survey Telescope (WFIRST) and First Light And Reionization Explorer (FLARE) (11 ≤ z ≤ 15). We conclude that the C IV 1549 Å, C III] 1909 Å, [O III] 4959/5007 Å and Hβ lines from even z ˜15 galaxies could be strong targets for TMT, E-ELT and JWST. We also find that magnification by gravitational lensing is of great help in detecting such high-z galaxies. According to our model, the C III] 1909 Å line in z > 9 galaxy candidates is detectable even using current facilities.

  7. The Carlisle Lakes-type chondrites: A new grouplet with high. Delta. sup 17 O and evidence for nebular oxidation

    SciTech Connect

    Weisberg, M.K. Brooklyn Coll., NY ); Prinz, M. ); Kojima, Hideyasu; Yanai, Keizo ); Clayton, R.N.; Mayeda, T.K. )

    1991-09-01

    Carlisle Lakes, ALH85151, and Y75302 are similar ungrouped chondrites which have petrologic and bulk compositional similarities to the ordinary chondrites, but are more oxidized; and their oxygen isotopic compositions differ. They represent a new grouplet which the authors call the Carlisle Lakes-type chondrites. They have the highest {Delta}{sup 17}O values (up to 2.91) measured to date. The whole chondrites and most of their chondrules plot on the same mass fractionation line on an oxygen 3-isotope diagram. They are olivine rich (>70 vol%), essentially metal free, and most olivine is FeO rich, equilibrated at Fa{sub 38}. Rare olivine and pyroxene grains in chondrules and fragments are zoned, and these are important in discerning the history of these chondrites. The zoning does not appear to have formed during crystallization from a melt droplet chondrule, but post-dated chondrule formation. Two hypotheses are postulated to explain the zoning: (1) parent-body thermal metamorphism and (2) nebular gas-solid exchange reactions accompanied by condensation of new FeO-rich olivine, utilizing existing olivine surfaces as nucleation sites. The occurrence of steep Fe-Mg compositional gradients of core-to-rim profiles, oscillatory zoning in olivine, fayalitic rims of Fa{sub 45} that exceed instead of approach the equilibrium composition of the matrix (Fa{sub 38}), and olivine-filled veins in zoned pyroxenes are more compatible with the nebular hypothesis. The Carlisle Lakes-type chondrites may have originally been derived from an ordinary chondrite-like precursor which was later oxidized, prior to its final lithification. However, the oxygen isotopic compositions of the whole chondrites and most of their chondrules suggest that the precursor probably formed in an oxygen isotopically distinct environment.

  8. Problems for the WELS classification of planetary nebula central stars: self-consistent nebular modelling of four candidates

    NASA Astrophysics Data System (ADS)

    Basurah, Hassan M.; Ali, Alaa; Dopita, Michael A.; Alsulami, R.; Amer, Morsi A.; Alruhaili, A.

    2016-05-01

    We present integral field unit (IFU) spectroscopy and self-consistent photoionization modelling for a sample of four southern Galactic planetary nebulae (PNe) with supposed weak emission-line central stars. The Wide Field Spectrograph on the ANU 2.3 m telescope has been used to provide IFU spectroscopy for NGC 3211, NGC 5979, My 60, and M 4-2 covering the spectral range of 3400-7000 Å. All objects are high-excitation non-Type I PNe, with strong He II emission, strong [Ne V] emission, and weak low-excitation lines. They all appear to be predominantly optically thin nebulae excited by central stars with Teff > 105 K. Three PNe of the sample have central stars which have been previously classified as weak emission-line stars (WELS), and the fourth also shows the characteristic recombination lines of a WELS. However, the spatially resolved spectroscopy shows that rather than arising in the central star, the C IV and N III recombination line emission is distributed in the nebula, and in some cases concentrated in discrete nebular knots. This may suggest that the WELS classification is spurious, and that, rather, these lines arise from (possibly chemically enriched) pockets of nebular gas. Indeed, from careful background subtraction we were able to identify three of the sample as being hydrogen rich O(H)-Type. We have constructed fully self-consistent photoionization models for each object. This allows us to independently determine the chemical abundances in the nebulae, to provide new model-dependent distance estimates, and to place the central stars on the Hertzsprung-Russell diagram. All four PNe have similar initial mass (1.5 < M/M⊙ < 2.0) and are at a similar evolutionary stage.

  9. Effects of high-energy milling on the solid-state synthesis of pure nano-sized Li4Ti5O12 for high power lithium battery applications

    NASA Astrophysics Data System (ADS)

    Han, Seung-Woo; Jeong, Joayoung; Yoon, Dang-Hyok

    2014-03-01

    Li4Ti5O12 was synthesized from Li2CO3 and anatase TiO2 using different degree of milling to test the hypothesis that finer starting materials can result in a smaller Li4Ti5O12 particle size and better high-rate discharging capacities. The degree of milling was controlled using three different ZrO2 media sizes for 3 hours of high-energy milling, whereas 5 mm balls were used for 24 hours ball milling. High-energy milling produced significantly finer starting materials and Li4Ti5O12 particles compared to those produced by ball milling. Among the three different balls used in high-energy milling, the 0.10 mm media showed the most favorable results. Pure Li4Ti5O12 with a mean particle size of 146 and 175 nm were synthesized by an economic solid-state reaction combined with high-energy milling using 0.05 and 0.10 mm beads, respectively. These pure nano-sized Li4Ti5O12 exhibited a much higher specific capacity and superior rate capability than those of coarse rutile TiO2-contained Li4Ti5O12 particles.

  10. KECK SPECTROSCOPY OF 3 < z < 7 FAINT LYMAN BREAK GALAXIES: THE IMPORTANCE OF NEBULAR EMISSION IN UNDERSTANDING THE SPECIFIC STAR FORMATION RATE AND STELLAR MASS DENSITY

    SciTech Connect

    Stark, Daniel P.; Robertson, Brant; Schenker, Matthew A.; Ellis, Richard; McLure, Ross; Dunlop, James

    2013-02-15

    The physical properties inferred from the spectral energy distributions (SEDs) of z > 3 galaxies have been influential in shaping our understanding of early galaxy formation and the role galaxies may play in cosmic reionization. Of particular importance is the stellar mass density at early times, which represents the integral of earlier star formation. An important puzzle arising from the measurements so far reported is that the specific star formation rates (sSFRs) evolve far less rapidly than expected in most theoretical models. Yet the observations underpinning these results remain very uncertain, owing in part to the possible contamination of rest-optical broadband light from strong nebular emission lines. To quantify the contribution of nebular emission to broadband fluxes, we investigate the SEDs of 92 spectroscopically confirmed galaxies in the redshift range 3.8 < z < 5.0 chosen because the H{alpha} line lies within the Spitzer/IRAC 3.6 {mu}m filter. We demonstrate that the 3.6 {mu}m flux is systematically in excess of that expected from stellar continuum alone, which we derive by fitting the SED with population synthesis models. No such excess is seen in a control sample of spectroscopically confirmed galaxies with 3.1 < z < 3.6 in which there is no nebular contamination in the IRAC filters. From the distribution of our 3.6 {mu}m flux excesses, we derive an H{alpha} equivalent width distribution and consider the implications for both the derived stellar masses and the sSFR evolution. The mean rest-frame H{alpha} equivalent width we infer at 3.8 < z < 5.0 (270 A) indicates that nebular emission contributes at least 30% of the 3.6 {mu}m flux and, by implication, nebular emission is likely to have a much greater impact for galaxies with z {approx_equal} 6-7 where both warm IRAC filters are contaminated. Via our empirically derived equivalent width distribution, we correct the available stellar mass densities and show that the sSFR evolves more rapidly at z

  11. OXYGEN ISOTOPIC COMPOSITIONS OF THE ALLENDE TYPE C CAIs: EVIDENCE FOR ISOTOPIC EXCHANGE DURING NEBULAR MELTING AND ASTEROIDAL THERMAL METAMORPHISM

    SciTech Connect

    Krot, A N; Chaussidon, M; Yurimoto, H; Sakamoto, N; Nagashima, K; Hutcheon, I D; MacPherson, G J

    2008-02-21

    that CAIs 100, 160 and CG5 experienced melting in an {sup 16}O-rich ({Delta}{sup 17}O < -20{per_thousand}) nebular gas in the CAI-forming region. The Type C and Type-B-like portions of CAI 6-1-72 experienced melting in an {sup 16}O-depleted ({Delta}{sup 17}O {ge} -13{per_thousand}) nebular gas. CAIs ABC, TS26 and 93 experienced isotopic exchange during re-melting in the presence of an {sup 16}O-poor ({Delta}{sup 17}O {ge} -10{per_thousand}) nebular gas in the chondrule-forming region(s). Subsequently, Allende Type C CAIs experienced post-crystallization isotopic exchange with an {sup 16}O-poor reservoir that affected largely melilite and anorthite. Because pseudomorphic replacement of lacy melilite by grossular, monticellite and forsterite occurred during thermal metamorphism, some oxygen isotopic exchange of melilite and anorthite must have continued after formation of these secondary minerals. We suggest that some or all oxygen isotopic exchange in melilite and anorthite occurred during fluid-assisted thermal metamorphism on the CV parent asteroid. Similar processes may have also affected melilite and anorthite of CAIs in metamorphosed CO chondrites.

  12. Production of substantially pure fructose

    DOEpatents

    Hatcher, Herbert J.; Gallian, John J.; Leeper, Stephen A.

    1990-01-01

    A process is disclosed for the production of substantially pure fructose from sucrose-containing substrates. The process comprises converting the sucrose to levan and glucose, purifying the levan by membrane technology, hydrolyzing the levan to form fructose monomers, and recovering the fructose.

  13. Gate-Driven Pure Spin Current in Graphene

    NASA Astrophysics Data System (ADS)

    Lin, Xiaoyang; Su, Li; Si, Zhizhong; Zhang, Youguang; Bournel, Arnaud; Zhang, Yue; Klein, Jacques-Olivier; Fert, Albert; Zhao, Weisheng

    2017-09-01

    The manipulation of spin current is a promising solution for low-power devices beyond CMOS. However, conventional methods, such as spin-transfer torque or spin-orbit torque for magnetic tunnel junctions, suffer from large power consumption due to frequent spin-charge conversions. An important challenge is, thus, to realize long-distance transport of pure spin current, together with efficient manipulation. Here, the mechanism of gate-driven pure spin current in graphene is presented. Such a mechanism relies on the electrical gating of carrier-density-dependent conductivity and spin-diffusion length in graphene. The gate-driven feature is adopted to realize the pure spin-current demultiplexing operation, which enables gate-controllable distribution of the pure spin current into graphene branches. Compared with the Elliott-Yafet spin-relaxation mechanism, the D'yakonov-Perel spin-relaxation mechanism results in more appreciable demultiplexing performance. The feature of the pure spin-current demultiplexing operation will allow a number of logic functions to be cascaded without spin-charge conversions and open a route for future ultra-low-power devices.

  14. Nebular spectra and abundance tomography of the Type Ia supernova SN 2011fe: a normal SN Ia with a stable Fe core

    NASA Astrophysics Data System (ADS)

    Mazzali, P. A.; Sullivan, M.; Filippenko, A. V.; Garnavich, P. M.; Clubb, K. I.; Maguire, K.; Pan, Y.-C.; Shappee, B.; Silverman, J. M.; Benetti, S.; Hachinger, S.; Nomoto, K.; Pian, E.

    2015-07-01

    A series of optical and one near-infrared nebular spectra covering the first year of the Type Ia supernova SN 2011fe are presented and modelled. The density profile that proved best for the early optical/ultraviolet spectra, `ρ-11fe', was extended to lower velocities to include the regions that emit at nebular epochs. Model ρ-11fe is intermediate between the fast deflagration model W7 and a low-energy delayed-detonation. Good fits to the nebular spectra are obtained if the innermost ejecta are dominated by neutron-rich, stable Fe-group species, which contribute to cooling but not to heating. The correct thermal balance can thus be reached for the strongest [Fe II] and [Fe III] lines to be reproduced with the observed ratio. The 56Ni mass thus obtained is ˜0.47 ± 0.05 M⊙. The bulk of 56Ni has an outermost velocity of ˜8500 km s-1. The mass of stable iron is ˜0.23 ± 0.03 M⊙. Stable Ni has low abundance, ˜10-2 M⊙. This is sufficient to reproduce an observed emission line near 7400 Å. A sub-Chandrasekhar explosion model with mass 1.02 M⊙ and no central stable Fe does not reproduce the observed line ratios. A mock model where neutron-rich Fe-group species are located above 56Ni following recent suggestions is also shown to yield spectra that are less compatible with the observations. The densities and abundances in the inner layers obtained from the nebular analysis, combined with those of the outer layers previously obtained, are used to compute a synthetic bolometric light curve, which compares favourably with the light curve of SN 2011fe.

  15. Playing with Powers

    ERIC Educational Resources Information Center

    Sriraman, Bharath; Strzelecki, Pawel

    2004-01-01

    This paper explores the wide range of pure mathematics that becomes accessible through the use of problems involving powers. In particular we stress the need to balance an applied and context based pedagogical and curricular approach to mathematics with the powerful pure mathematics beneath the simplicity of easily stated and understandable…

  16. Production of substantially pure fructose

    SciTech Connect

    Hatcher, H.J.; Gallian, J.J.; Leeper, S.A.

    1990-05-22

    This patent describes a process for the production of a substantially pure product containing greater than 60% fructose. It comprises: combining a sucrose-containing substrate with effective amounts of a levansucrase enzyme preparation to form levan and glucose; purifying the levan by at least one of the following purification methods: ultrafiltration, diafiltration, hyperfiltration, reverse osmosis, liquid--liquid partition, solvent extraction, chromatography, and precipitation; hydrolyzing the levan to form fructose substantially free of glucose and sucrose; and recovering the fructose by at least one of the following recovery methods: hyperfiltration, reverse osmosis, evaporation, drying, crystallization, and chromatography.

  17. Toxicological evaluation of pure hydroxytyrosol.

    PubMed

    Auñon-Calles, David; Canut, Lourdes; Visioli, Francesco

    2013-05-01

    Of all the phenolic constituents of olives and extra virgin olive oil, hydroxytyrosol is currently being actively exploited as a potential supplement or preservative to be employed in the nutraceutical, cosmeceutical, and food industry. In terms of safety profile, hydroxytyrosol has only been investigated as the predominant part of raw olive mill waste water extracts, due to the previous unavailability of appropriate quantities of the pure compound. We report the toxicological evaluation of hydroxytyrosol and, based on the results, propose a No Observed Adverse Effects Level (NOAEL) of 500mg/kg/d.

  18. Synthesis of Enantiomerically Pure Anthracyclinones

    NASA Astrophysics Data System (ADS)

    Achmatowicz, Osman; Szechner, Barbara

    The anthracycline antibiotics are among the most important clinical drugs used in the treatment of human cancer. The search for new agents with improved therapeutic efficacy and reduced cardiotoxicity stimulated considerable efforts in the synthesis of new analogues. Since the biological activity of anthracyclines depends on their natural absolute configuration, various strategies for the synthesis of enantiomerically pure anthracyclinones (aglycones) have been developed. They comprise: resolution of racemic intermediate, incorporation of a chiral fragment derived from natural and non-natural chiral pools, asymmetric synthesis with the use of a chiral auxiliary or a chiral reagent, and enantioselective catalysis. Synthetic advances towards enantiopure anthracyclinones reported over the last 17 years are reviewed.

  19. Pure dysarthria due to an insular infarction.

    PubMed

    Hiraga, Akiyuki; Tanaka, Saiko; Kamitsukasa, Ikuo

    2010-06-01

    Cortical infarction presenting with pure dysarthria is rarely reported. Previous studies have reported pure dysarthria due to cortical stroke at the precentral gyrus or middle frontal gyrus. We report a 72-year-old man who developed pure dysarthria caused by an acute cortical infarction in the insular cortex. The role of the insula in language has been difficult to assess clinically because of the rarity of pure insular strokes. Our patient showed pure dysarthria without aphasia, indicating that pure dysarthria can be the sole manifestation of insular infarctions.

  20. HIGH-TEMPERATURE PROCESSING OF SOLIDS THROUGH SOLAR NEBULAR BOW SHOCKS: 3D RADIATION HYDRODYNAMICS SIMULATIONS WITH PARTICLES

    SciTech Connect

    Boley, A. C.; Morris, M. A.; Desch, S. J.

    2013-10-20

    A fundamental, unsolved problem in solar system formation is explaining the melting and crystallization of chondrules found in chondritic meteorites. Theoretical models of chondrule melting in nebular shocks have been shown to be consistent with many aspects of thermal histories inferred for chondrules from laboratory experiments; but, the mechanism driving these shocks is unknown. Planetesimals and planetary embryos on eccentric orbits can produce bow shocks as they move supersonically through the disk gas, and are one possible source of chondrule-melting shocks. We investigate chondrule formation in bow shocks around planetoids through three-dimensional radiation hydrodynamics simulations. A new radiation transport algorithm that combines elements of flux-limited diffusion and Monte Carlo methods is used to capture the complexity of radiative transport around bow shocks. An equation of state that includes the rotational, vibrational, and dissociation modes of H{sub 2} is also used. Solids are followed directly in the simulations and their thermal histories are recorded. Adiabatic expansion creates rapid cooling of the gas, and tail shocks behind the embryo can cause secondary heating events. Radiative transport is efficient, and bow shocks around planetoids can have luminosities ∼few× 10{sup –8} L{sub ☉}. While barred and radial chondrule textures could be produced in the radiative shocks explored here, porphyritic chondrules may only be possible in the adiabatic limit. We present a series of predicted cooling curves that merit investigation in laboratory experiments to determine whether the solids produced by bow shocks are represented in the meteoritic record by chondrules or other solids.

  1. Nebular phase observations of the Type-Ib supernova iPTF13bvn favour a binary progenitor

    NASA Astrophysics Data System (ADS)

    Kuncarayakti, H.; Maeda, K.; Bersten, M. C.; Folatelli, G.; Morrell, N.; Hsiao, E. Y.; González-Gaitán, S.; Anderson, J. P.; Hamuy, M.; de Jaeger, T.; Gutiérrez, C. P.; Kawabata, K. S.

    2015-07-01

    Aims: We present and analyse late-time observations of the Type-Ib supernova with possible pre-supernova progenitor detection, iPTF13bvn, which were done ~300 days after the explosion. We discuss them in the context of constraints on the supernova's progenitor. Previous studies have proposed two possible natures for the progenitor of the supernova, i.e. a massive Wolf-Rayet star or a lower-mass star in a close binary system. Methods: Our observations show that the supernova has entered the nebular phase, with the spectrum dominated by Mg I]λλ4571, [O I]λλ6300, 6364, and [Ca II]λλ7291, 7324 emission lines. We measured the emission line fluxes to estimate the core oxygen mass and compared the [O I]/[Ca II] line ratio with other supernovae. Results.The core oxygen mass of the supernova progenitor was estimated to be ≲0.7 M⊙, which implies initial progenitor mass that does not exceed ~15-17 M⊙.Since the derived mass is too low for a single star to become a Wolf-Rayet star, this result lends more support to the binary nature of the progenitor star of iPTF13bvn. The comparison of [O I]/[Ca II] line ratio with other supernovae also shows that iPTF13bvn appears to be in close association with the lower mass progenitors of stripped-envelope and Type-II supernovae. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the US National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU); Chilean Telescope Time Allocation Committee proposal CN2014A-91.

  2. Galactic planetary nebulae with precise nebular abundances as a tool to understand the evolution of asymptotic giant branch stars

    NASA Astrophysics Data System (ADS)

    García-Hernández, D. A.; Ventura, P.; Delgado-Inglada, G.; Dell'Agli, F.; Di Criscienzo, M.; Yagüe, A.

    2016-09-01

    We present nucleosynthesis predictions (HeCNOCl) from asymptotic giant branch (AGB) models, with diffusive overshooting from all the convective borders, in the metallicity range Z⊙/4 < Z < 2 Z⊙. They are compared to recent precise nebular abundances in a sample of Galactic planetary nebulae (PNe) that is divided among double-dust chemistry (DC) and oxygen-dust chemistry (OC) according to the infrared dust features. Unlike the similar subsample of Galactic carbon-dust chemistry PNe recently analysed by us, here the individual abundance errors, the higher metallicity spread, and the uncertain dust types/subtypes in some PNe do not allow a clear determination of the AGB progenitor masses (and formation epochs) for both PNe samples; the comparison is thus more focused on a object-by-object basis. The lowest metallicity OC PNe evolve from low-mass (˜1 M⊙) O-rich AGBs, while the higher metallicity ones (all with uncertain dust classifications) display a chemical pattern similar to the DC PNe. In agreement with recent literature, the DC PNe mostly descend from high-mass (M ≥ 3.5 M⊙) solar/supersolar metallicity AGBs that experience hot bottom burning (HBB), but other formation channels in low-mass AGBs like extra mixing, stellar rotation, binary interaction, or He pre-enrichment cannot be disregarded until more accurate C/O ratios would be obtained. Two objects among the DC PNe show the imprint of advanced CNO processing and deep second dredge-up, suggesting progenitors masses close to the limit to evolve as core collapse supernovae (above 6M⊙). Their actual C/O ratio, if confirmed, indicate contamination from the third dredge-up, rejecting the hypothesis that the chemical composition of such high-metallicity massive AGBs is modified exclusively by HBB.

  3. Multiple pure tone noise prediction

    NASA Astrophysics Data System (ADS)

    Han, Fei; Sharma, Anupam; Paliath, Umesh; Shieh, Chingwei

    2014-12-01

    This paper presents a fully numerical method for predicting multiple pure tones, also known as “Buzzsaw” noise. It consists of three steps that account for noise source generation, nonlinear acoustic propagation with hard as well as lined walls inside the nacelle, and linear acoustic propagation outside the engine. Noise generation is modeled by steady, part-annulus computational fluid dynamics (CFD) simulations. A linear superposition algorithm is used to construct full-annulus shock/pressure pattern just upstream of the fan from part-annulus CFD results. Nonlinear wave propagation is carried out inside the duct using a pseudo-two-dimensional solution of Burgers' equation. Scattering from nacelle lip as well as radiation to farfield is performed using the commercial solver ACTRAN/TM. The proposed prediction process is verified by comparing against full-annulus CFD simulations as well as against static engine test data for a typical high bypass ratio aircraft engine with hardwall as well as lined inlets. Comparisons are drawn against nacelle unsteady pressure transducer measurements at two axial locations as well as against near- and far-field microphone array measurements outside the duct. This is the first fully numerical approach (no experimental or empirical input is required) to predict multiple pure tone noise generation, in-duct propagation and far-field radiation. It uses measured blade coordinates to calculate MPT noise.

  4. Pure optical dynamical color encryption

    NASA Astrophysics Data System (ADS)

    Mosso, Fabian; Tebaldi, Myrian; Fredy Barrera, John; Bolognini, Néstor; Torroba, Roberto

    2011-07-01

    We introduce a way to encrypt-decrypt a color dynamical phenomenon using a pure optical alternative. We split the three basic chromatic channels composing the input, and then each channel is processed through a 4f encoding method and a theta modulation applied to the each encrypted frame in every channel. All frames for a single channel are multiplexed. The same phase mask is used to encode all the information. Unlike the usual procedure we do not multiplex the three chromatic channels into a single encoding media, because we want to decrypt the information in real time. Then, we send to the decoding station the phase mask and the three packages each one containing the multiplexing of a single channel. The end user synchronizes and decodes the information contained in the separate channels. Finally, the decoding information is conveyed together to bring the decoded dynamical color phenomenon in real-time. We present material that supports our concepts.

  5. Pure optical dynamical color encryption.

    PubMed

    Mosso, Fabian; Tebaldi, Myrian; Barrera, John Fredy; Bolognini, Néstor; Torroba, Roberto

    2011-07-18

    We introduce a way to encrypt-decrypt a color dynamical phenomenon using a pure optical alternative. We split the three basic chromatic channels composing the input, and then each channel is processed through a 4f encoding method and a theta modulation applied to the each encrypted frame in every channel. All frames for a single channel are multiplexed. The same phase mask is used to encode all the information. Unlike the usual procedure we do not multiplex the three chromatic channels into a single encoding media, because we want to decrypt the information in real time. Then, we send to the decoding station the phase mask and the three packages each one containing the multiplexing of a single channel. The end user synchronizes and decodes the information contained in the separate channels. Finally, the decoding information is conveyed together to bring the decoded dynamical color phenomenon in real-time. We present material that supports our concepts.

  6. 76 FR 69284 - Pure Magnesium From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-08

    ... COMMISSION Pure Magnesium From China Determination On the basis of the record \\1\\ developed in the subject... order on pure magnesium from China would be likely to lead to continuation or recurrence of material... USITC Publication 4274 (October 2011), entitled Pure Magnesium from China: Investigation No. 731-TA-696...

  7. Analysis of pure maple syrup consumers

    Treesearch

    Paul E. Sendak

    1974-01-01

    Virtually all of the pure maple syrup productim in the United States is in the northern states of Maine, Massachusetts, Michigan, New Hampshire, New York, Ohio, Pennsylvania, Vermont, and Wisconsin. Pure maple syrup users living in the maple production area and users living in other areas of the United States were asked a series of questions about their use of pure...

  8. Dual Target Search is Neither Purely Simultaneous nor Purely Successive.

    PubMed

    Cave, Kyle R; Menneer, Tamaryn; Nomani, Mohammad S; Stroud, Michael J; Donnelly, Nick

    2017-08-31

    Previous research shows that visual search for two different targets is less efficient than search for a single target. Stroud, Menneer, Cave and Donnelly (2012) concluded that two target colours are represented separately based on modeling the fixation patterns. Although those analyses provide evidence for two separate target representations, they do not show whether participants search simultaneously for both targets, or first search for one target and then the other. Some studies suggest that multiple target representations are simultaneously active, while others indicate that search can be voluntarily simultaneous, or switching, or a mixture of both. Stroud et al.'s participants were not explicitly instructed to use any particular strategy. These data were revisited to determine which strategy was employed. Each fixated item was categorised according to whether its colour was more similar to one target or the other. Once an item similar to one target is fixated, the next fixated item is more likely to be similar to that target than the other, showing that at a given moment during search, one target is generally favoured. However, the search for one target is not completed before search for the other begins. Instead, there are often short runs of one or two fixations to distractors similar to one target, with each run followed by a switch to the other target. Thus, the results suggest that one target is more highly weighted than the other at any given time, but not to the extent that search is purely successive.

  9. OT1_rrubin_1: Herschel's Opportunity to Solve the Nebular Abundance Problem While Creating a Legacy Planetary Nebulae Dataset

    NASA Astrophysics Data System (ADS)

    Rubin, R.

    2010-07-01

    Abundance surveys of a large sample of Galactic planetary nebulae (PNe) have led to the discovery of a group of super-metal-rich nebulae whose spectra show prominent optical recombination lines (ORLs) from C, N, O, and Ne ions. The heavy element abundances derived from ORLs for several PNe are a factor >10 higher than those derived from the traditional method based on collisionally excited lines (CELs). This ratio is called the abundance discrepancy factor (adf). A promising proposition to explain the nebular abundance problem posits that these nebulae contain (at least) two distinct regions - one of "normal" electron temperature, Te (~10000 K) and chemical composition (~solar) and another of very low Te (< 1000) that is H-deficient, thus having high metal abundances relative to H. The latter component emits strong heavy element ORLs and IR fine-structure (FS) CELs but essentially no optical/UV CELs. Efforts to directly detect these inclusions in PNe have been unsuccessful to date. However, there is mounting circumstantial evidence for their existence, such as presented in our recent paper that modeled the high-adf PN NGC 6153 using a 3-D photoionization code. The models that included the low Te, H-deficient knots fit most observations far better than did those models without the clumps. With the launch of Herschel, there is finally the capability to perform a test we've been dreaming of. Measurements have shown that the adf varies with position in a PN and is highest close to the central star. The very low Te inclusions must be cooled via FS IR lines. We propose to use Herschel to map the FS IR lines in 5 bright PNe on the largest adf list, to find if these lines peak where the adf peaks. These spectra will also provide a feast for our other team expertise/interests: a legacy dataset of molecular lines to explore PDRs, how the central star interacts with the AGB ejecta and shapes the PN, how the shocks are produced, what comprises the chemistry of the molecular

  10. Electromigration revisited: competition between Kirkendall shift and backstress in pure metals and two-phase alloys

    NASA Astrophysics Data System (ADS)

    Gusak, A.; Wierzba, B.; Danielewski, M.

    2015-04-01

    The simple phenomenological model and analytical approach of electromigration in the two-phase alloy (solder) under combined influence of the Kirkendall effect, backstress and sedimentation is presented. It is compared with electromigration in pure metal under condition of quasi-equilibrium vacancies (unlimited power of vacancy sinks-sources) and electromigration in pure metal with account of nonequilibrium vacancies.

  11. Mixtures of maximally entangled pure states

    SciTech Connect

    Flores, M.M. Galapon, E.A.

    2016-09-15

    We study the conditions when mixtures of maximally entangled pure states remain entangled. We found that the resulting mixed state remains entangled when the number of entangled pure states to be mixed is less than or equal to the dimension of the pure states. For the latter case of mixing a number of pure states equal to their dimension, we found that the mixed state is entangled provided that the entangled pure states to be mixed are not equally weighted. We also found that one can restrict the set of pure states that one can mix from in order to ensure that the resulting mixed state is genuinely entangled. Also, we demonstrate how these results could be applied as a way to detect entanglement in mixtures of the entangled pure states with noise.

  12. Optical light bullets in a pure Kerr medium.

    PubMed

    Fibich, Gadi; Ilan, Boaz

    2004-04-15

    We show that small negative fourth-order dispersion can arrest spatiotemporal collapse of ultrashort pulses with anomalous dispersion in a planar waveguide with pure Kerr nonlinearity, resulting in (2 + 1)D optical bullets. Similarly to solitons, these bullets undergo elastic collisions. Since these bullets can self-trap from noisy Gaussian input beams and propagate without any power losses, this result may be used to realize experimentally stable, nondissipative optical bullets.

  13. Purely wavelength- and amplitude-modulated quartz-enhanced photoacoustic spectroscopy.

    PubMed

    Patimisco, Pietro; Sampaolo, Angelo; Bidaux, Yves; Bismuto, Alfredo; Scott, Marshall; Jiang, James; Muller, Antoine; Faist, Jerome; Tittel, Frank K; Spagnolo, Vincenzo

    2016-11-14

    We report here on a quartz-enhanced photoacoustic (QEPAS) sensor employing a quantum cascade laser (QCL) structure capable of operating in a pure amplitude or wavelength modulation configuration. The QCL structure is composed of three electrically independent sections: Gain, Phase (PS) and Master Oscillator (MO). Selective current pumping of these three sections allows obtaining laser wavelength tuning without changes in the optical power, and power modulation without emission wavelength shifts. A pure QEPAS amplitude modulation condition is obtained by modulating the PS current, while pure wavelength modulation is achieved by modulating simultaneously the MO and PS QCL sections and slowly scanning the DC current level injected in the PS section.

  14. RF Sputtering for preparing substantially pure amorphous silicon monohydride

    DOEpatents

    Jeffrey, Frank R.; Shanks, Howard R.

    1982-10-12

    A process for controlling the dihydride and monohydride bond densities in hydrogenated amorphous silicon produced by reactive rf sputtering of an amorphous silicon target. There is provided a chamber with an amorphous silicon target and a substrate therein with the substrate and the target positioned such that when rf power is applied to the target the substrate is in contact with the sputtering plasma produced thereby. Hydrogen and argon are fed to the chamber and the pressure is reduced in the chamber to a value sufficient to maintain a sputtering plasma therein, and then rf power is applied to the silicon target to provide a power density in the range of from about 7 watts per square inch to about 22 watts per square inch to sputter an amorphous silicon hydride onto the substrate, the dihydride bond density decreasing with an increase in the rf power density. Substantially pure monohydride films may be produced.

  15. Method of preparing pure fluorine gas

    DOEpatents

    Asprey, Larned B.

    1976-01-01

    A simple, inexpensive system for purifying and storing pure fluorine is described. The method utilizes alkali metal-nickel fluorides to absorb tank fluorine by forming nickel complex salts and leaving the gaseous impurities which are pumped away. The complex nickel fluoride is then heated to evolve back pure gaseous fluorine.

  16. Pure ovarian choriocarcinoma: report of two cases

    PubMed Central

    Mood, Narges Izadi; Samadi, Nasrin; Rahimi-Moghaddam, Parvaneh; Sarmadi, Soheila; Eftekhar, Zahra; Yarandi, Fariba

    2009-01-01

    Pure primary ovarian choriocarcinoma is an extremely rare condition of gestational or nongestational origin. The possibility of gestational origin can be suspected by the presence of a corpus luteum of pregnancy but definite diagnosis would be based on genetic analysis. Here, we present two cases of pure ovarian choriocarcinoma in the forth decade of life with the possibility of gestational origin. PMID:21772904

  17. Pure red cell hypoplasia secondary to isoniazid.

    PubMed Central

    Lewis, C. R.; Manoharan, A.

    1987-01-01

    We describe a 77 year old man who developed pure red cell aplasia while receiving antituberculous therapy including isoniazid. Prompt recovery occurred following cessation of isoniazid. In this paper we also review previously described case reports of isoniazid-induced pure red cell aplasia. PMID:3120168

  18. Diverse Anhydrous Silicates in a Fine-Grained Rim in the Weakly Altered CM2 Chondrite Queen Elizabeth Range 97990: Evidence for the Localized Preservation of Pristine Nebular Dust in CM Chondrites.

    NASA Astrophysics Data System (ADS)

    Brearley, A. J.

    2016-08-01

    A fine-grained rim the QUE 97990 CM2 chondrite contains diverse submicron crystalline anhydrous silicates, including olivines, low-Ca and high Ca pyroxenes and represents a more pristine sample of nebular dust than is present in most CM chondrites.

  19. Hydrogen Abundances in Metal Grains from the Hammadah Al Hamra (HaH) 237 Metal-rich Chondrite: A Test of the Nebular-Formation Theory

    NASA Technical Reports Server (NTRS)

    Lauretta, D. S.; Guan, Y.; Leshin, L. A.

    2005-01-01

    The Bencubbin-like (CB) chondrites are metal-rich, primitive meteorites [1,2]. Some of these chondrites (HaH 237, QUE 94411) contain compositionally zoned metal grains with near-chondritic bulk compositions. Thermodynamic modeling of the zoning patterns in these grains suggests that they were formed by condensation in a region of the solar nebula with enhanced dust/gas ratios and a total pressure of 10(exp -4) bars at temperatures between 1400 - 1500 K [3]. If these predictions are correct than the metal grains would have been exposed to abundant H2 gas, which comprises the bulk of nebular systems. Since Fe-based alloys can absorb significant quantities of H, metal grains formed in the solar nebula should contain measurable abundances of H.

  20. Ca-Fe and Alkali-Halide Alteration of an Allende Type B CAI: Aqueous Alteration in Nebular or Asteroidal Settings

    NASA Technical Reports Server (NTRS)

    Ross, D. K.; Simon, J. I.; Simon, S. B.; Grossman, L.

    2012-01-01

    Ca-Fe and alkali-halide alteration of CAIs is often attributed to aqueous alteration by fluids circulating on asteroidal parent bodies after the various chondritic components have been assembled, although debate continues about the roles of asteroidal vs. nebular modification processes [1-7]. Here we report de-tailed observations of alteration products in a large Type B2 CAI, TS4 from Allende, one of the oxidized subgroup of CV3s, and propose a speculative model for aqueous alteration of CAIs in a nebular setting. Ca-Fe alteration in this CAI consists predominantly of end-member hedenbergite, end-member andradite, and compositionally variable, magnesian high-Ca pyroxene. These phases are strongly concentrated in an unusual "nodule" enclosed within the interior of the CAI (Fig. 1). The Ca, Fe-rich nodule superficially resembles a clast that pre-dated and was engulfed by the CAI, but closer inspection shows that relic spinel grains are enclosed in the nodule, and corroded CAI primary phases interfinger with the Fe-rich phases at the nodule s margins. This CAI also contains abundant sodalite and nepheline (alkali-halide) alteration that occurs around the rims of the CAI, but also penetrates more deeply into the CAI. The two types of alteration (Ca-Fe and alkali-halide) are adjacent, and very fine-grained Fe-rich phases are associated with sodalite-rich regions. Both types of alteration appear to be replacive; if that is true, it would require substantial introduction of Fe, and transport of elements (Ti, Al and Mg) out of the nodule, and introduction of Na and Cl into alkali-halide rich zones. Parts of the CAI have been extensively metasomatized.

  1. THE ABUNDANCES OF LIGHT NEUTRON-CAPTURE ELEMENTS IN PLANETARY NEBULAE. III. THE IMPACT OF NEW ATOMIC DATA ON NEBULAR SELENIUM AND KRYPTON ABUNDANCE DETERMINATIONS

    SciTech Connect

    Sterling, N. C.; Porter, R. L.; Dinerstein, Harriet L. E-mail: ryanlporter@gmail.com

    2015-06-22

    The detection of neutron(n)-capture elements in several planetary nebulae (PNe) has provided a new means of investigating s-process nucleosynthesis in low-mass stars. However, a lack of atomic data has inhibited accurate trans-iron element abundance determinations in astrophysical nebulae. Recently, photoionization (PI) and recombination data were determined for Se and Kr, the two most widely detected n-capture elements in nebular spectra. We have incorporated these new data into the photoionization code Cloudy. To test the atomic data, numerical models were computed for 15 PNe that exhibit emission lines from multiple Kr ions. We found systematic discrepancies between the predicted and observed emission lines that are most likely caused by inaccurate PI and recombination data. These discrepancies were removed by adjusting the Kr{sup +}–Kr{sup 3+} PI cross sections within their cited uncertainties and the dielectronic recombination rate coefficients by slightly larger amounts. From grids of models spanning the physical conditions encountered in PNe, we derive new, broadly applicable ionization correction factor (ICF) formulae for calculating Se and Kr elemental abundances. The ICFs were applied to our previous survey of near-infrared [Kr iii] and [Se iv] emission lines in 120 PNe. The revised Se and Kr abundances are 0.1–0.3 dex lower than former estimates, with average values of [Se/(O, Ar)] = 0.12 ± 0.27 and [Kr/(O, Ar)] = 0.82 ± 0.29, but correlations previously found between their abundances and other nebular and stellar properties are unaffected. We also find a tendency for high-velocity PNe that can be associated with the Galactic thick disk to exhibit larger s-process enrichments than low-velocity PNe belonging to the thin-disk population.

  2. Conformal pure radiation with parallel rays

    NASA Astrophysics Data System (ADS)

    Leistner, Thomas; Nurowski, Paweł

    2012-03-01

    We define pure radiation metrics with parallel rays to be n-dimensional pseudo-Riemannian metrics that admit a parallel null line bundle K and whose Ricci tensor vanishes on vectors that are orthogonal to K. We give necessary conditions in terms of the Weyl, Cotton and Bach tensors for a pseudo-Riemannian metric to be conformal to a pure radiation metric with parallel rays. Then, we derive conditions in terms of the tractor calculus that are equivalent to the existence of a pure radiation metric with parallel rays in a conformal class. We also give analogous results for n-dimensional pseudo-Riemannian pp-waves.

  3. Simplified D = 11 pure spinor b ghost

    NASA Astrophysics Data System (ADS)

    Berkovits, Nathan; Guillen, Max

    2017-07-01

    A b-ghost was constructed for the D = 11 non-minimal pure spinor superparticle by requiring that { Q, b} = T where Q={Λ}^{α }{D}_{α }+{R}^{α }{\\overline{W}}_{α } is the usual non-minimal pure spinor BRST operator. As was done for the D = 10 b-ghost, we will show that the D = 11 b-ghost can be simplified by introducing an SO(10, 1) fermionic vector {\\overline{Σ}}^i constructed out of the fermionic spinor D α and pure spinor variables. This simplified version will be shown to satisfy { Q, b} = T and { b, b} = BRST - trivial.

  4. Making Pure Fine-Grained Inorganic Powder

    NASA Technical Reports Server (NTRS)

    Wood, C.

    1985-01-01

    Sustained arc plasma chemical reactor fabricates very-fine-grained inorganic solids having low thermal conductivity. Powder fabrication method, based on plasma tube technique produces pure solids without contamination commonly produced by grinding.

  5. Quantifying the coherence of pure quantum states

    NASA Astrophysics Data System (ADS)

    Chen, Jianxin; Grogan, Shane; Johnston, Nathaniel; Li, Chi-Kwong; Plosker, Sarah

    2016-10-01

    In recent years, several measures have been proposed for characterizing the coherence of a given quantum state. We derive several results that illuminate how these measures behave when restricted to pure states. Notably, we present an explicit characterization of the closest incoherent state to a given pure state under the trace distance measure of coherence. We then use this result to show that the states maximizing the trace distance of coherence are exactly the maximally coherent states. We define the trace distance of entanglement and show that it coincides with the trace distance of coherence for pure states. Finally, we give an alternate proof to a recent result that the ℓ1 measure of coherence of a pure state is never smaller than its relative entropy of coherence.

  6. Dark fermentation on biohydrogen production: Pure culture.

    PubMed

    Lee, Duu-Jong; Show, Kuan-Yeow; Su, Ay

    2011-09-01

    Biohydrogen is regarded as an attractive future clean energy carrier due to its high energy content and environmental-friendly conversion. While biohydrogen production is still in the early stage of development, there have been a variety of laboratory- and pilot-scale systems developed with promising potential. This work presents a review of literature reports on the pure hydrogen-producers under anaerobic environment. Challenges and perspective of biohydrogen production with pure cultures are also outlined.

  7. Diphenylhydantoin-induced pure red cell aplasia.

    PubMed

    Rusia, Usha; Malhotra, Purnima; Joshi, Panul

    2006-01-01

    Pure red cell aplasia is an uncommon complication of diphenylhydantoin therapy. It has not been reported in Indian literature. Awareness of the entity helps in establishing the cause of anaemia in these patients and alerts the physicians to the need of comprehensive haematological monitoring in these patients. A case of 58-year-old male who developed pure red cell aplasia following three months of diphenylhydantoin therapy is reported here.

  8. Purely extradural spinal nerve root hemangioblastomas

    PubMed Central

    Aytar, Murat Hamit; Yener, Ulaş; Ekşi, Murat Şakir; Kaya, Behram; Özgen, Serdar; Sav, Aydin; Alanay, Ahmet

    2016-01-01

    Spinal nerve root hemangioblastomas present mostly as intradural-extradurally. Purely extradural spinal nerve root hemangioblastoma is a very rare entity. In this study, we aimed to analyze epidemiological perspectives of purely extradural spinal nerve root hemangioblastomas presented in English medical literature in addition to our own exemplary case. PubMed/MEDLINE was searched using the terms “hemangioblastoma,” “extradural,” “spinal,” and “nerve root.” Demographical variables of age, gender, concomitant presence of von Hippel–Lindau (VHL) disease; spinal imaging and/or intraoperative findings for tumor location were surveyed from retrieved articles. There are 38 patients with purely extradural spinal nerve root hemangioblastoma. The median age is 45 years (range = 24–72 years). Female:male ratio is 0.6. Spinal levels for purely extradural spinal nerve root hemangioblastomas, in order of decreasing frequency, are thoracic (48.6%), cervical (13.5%), lumbar (13.5%), lumbosacral (10.8%), sacral (8.1%), and thoracolumbar (5.4%). Concomitant presence of VHL disease is 45%. Purely extradural spinal nerve root hemangioblastomas are very rare and can be confused with other more common extradural spinal cord tumors. Concomitant presence of VHL disease is observed in less than half of the patients with purely extradural spinal nerve root hemangioblastomas. Surgery is the first-line treatment in these tumors. PMID:27891027

  9. Rehabilitation of pure alexia: A review

    PubMed Central

    Starrfelt, Randi; Ólafsdóttir, Rannveig Rós; Arendt, Ida-Marie

    2013-01-01

    Acquired reading problems caused by brain injury (alexia) are common, either as a part of an aphasic syndrome, or as an isolated symptom. In pure alexia, reading is impaired while other language functions, including writing, are spared. Being in many ways a simple syndrome, one would think that pure alexia was an easy target for rehabilitation efforts. We review the literature on rehabilitation of pure alexia from 1990 to the present, and find that patients differ widely on several dimensions, such as alexia severity and associated deficits. Many patients reported to have pure alexia in the reviewed studies, have associated deficits such as agraphia or aphasia and thus do not strictly conform to the diagnosis. Few studies report clear and generalisable effects of training, none report control data, and in many cases the reported findings are not supported by statistics. We can, however, tentatively conclude that Multiple Oral Re-reading techniques may have some effect in mild pure alexia where diminished reading speed is the main problem, while Tacile-Kinesthetic training may improve letter identification in more severe cases of alexia. There is, however, still a great need for well-designed and controlled studies of rehabilitation of pure alexia. PMID:23808895

  10. Pure laparoscopic hepatectomy combined with a pure laparoscopic pringle maneuver in patients with severe cirrhosis.

    PubMed

    Miyagi, Shigehito; Nakanishi, Chikashi; Kawagishi, Naoki; Kamei, Takashi; Satomi, Susumu; Ohuchi, Noriaki

    2015-01-01

    Laparoscopic hepatectomy is a standard surgical procedure. However, it is difficult to perform in patients with severe cirrhosis because of fibrosis and a high risk of hemorrhage. We report our recent experience in five cases of pure laparoscopic hepatectomy combined with a pure laparoscopic Pringle maneuver in patients with severe cirrhosis. From 2012 to 2014, we performed pure laparoscopic partial hepatectomy in five patients with severe liver cirrhosis (indocyanine green retention rate at 15 min [ICG R15] >30% and fibrosis stage f4). A pure laparoscopic Pringle maneuver was employed in all patients. We investigated operative time, blood loss, duration of hospitalization and the days when discharge was possible, and compared these findings with those of patients with a normal liver (ICG R15 <10%, f0) who underwent pure laparoscopic partial hepatectomy during the same period (n = 7). As a result, operative time, blood loss, duration of hospitalization and the days when discharge was possible were similar in patients with cirrhosis undergoing pure laparoscopic hepatectomy combined with a pure laparoscopic Pringle maneuver to those in patients with a normal liver undergoing pure laparoscopic partial hepatectomy. In conclusion, pure laparoscopic hepatectomy combined with a pure laparoscopic Pringle maneuver appears to be safe in patients with severe cirrhosis.

  11. Theory of resonance fluorescence from a solid-state cavity QED system: Effects of pure dephasing

    SciTech Connect

    Koshino, Kazuki

    2011-09-15

    We theoretically analyze the resonance fluorescence of a solid-state cavity quantum electrodynamics (QED) system that consists of a quantum dot and a cavity. We clarify the effects of pure dephasing by investigating the elastic and inelastic scattering probabilities, the fluorescence power spectrum, and the energy exchange with the environment. Pure dephasing interactions with the environment both enhance nonresonant coupling between the dot and the cavity and enable the pump light to continuously absorb energy from the environment under appropriate conditions.

  12. Relations among pure-tone sound stimuli, neural activity, and the loudness sensation

    NASA Technical Reports Server (NTRS)

    Howes, W. L.

    1972-01-01

    Both the physiological and psychological responses to pure-tone sound stimuli are used to derive formulas which: (1) relate the loudness, loudness level, and sound-pressure level of pure tones; (2) apply continuously over most of the acoustic regime, including the loudness threshold; and (3) contain no undetermined coefficients. Some of the formulas are fundamental for calculating the loudness of any sound. Power-law formulas relating the pure-tone sound stimulus, neural activity, and loudness are derived from published data.

  13. Nokia PureView oversampling technology

    NASA Astrophysics Data System (ADS)

    Vuori, Tero; Alakarhu, Juha; Salmelin, Eero; Partinen, Ari

    2013-03-01

    This paper describes Nokia's PureView oversampling imaging technology as well as the product, Nokia 808 PureView, featuring it. The Nokia PureView imaging technology is the combination of a large, super high resolution 41Mpix with high performance Carl Zeiss optics. Large sensor enables a pixel oversampling technique that reduces an image taken at full resolution into a lower resolution picture, thus achieving higher definition and light sensitivity. One oversampled super pixel in image file is formed by using many sensor pixels. A large sensor enables also a lossless zoom. If a user wants to use the lossless zoom, the sensor image is cropped. However, up-scaling is not needed as in traditional digital zooming usually used in mobile devices. Lossless zooming means image quality that does not have the digital zooming artifacts as well as no optical zooming artifacts like zoom lens system distortions. Zooming with PureView is also completely silent. PureView imaging technology is the result of many years of research and development and the tangible fruits of this work are exceptional image quality, lossless zoom, and superior low light performance.

  14. Structural anatomy of pure and hemianopic alexia.

    PubMed

    Leff, A P; Spitsyna, G; Plant, G T; Wise, R J S

    2006-09-01

    The two most common types of acquired reading disorder resulting from damage to the territory of the dominant posterior cerebral artery are hemianopic and pure alexia. Patients with pronounced hemianopic alexia have a right homonymous hemianopia that encroaches into central or parafoveal vision; they read individual words well, but generate inefficient reading saccades when reading along a line of text. Patients with pure alexia also often have a hemianopia but are more disabled, making frequent errors on individual words; they have sustained damage to a brain region that supports efficient word identification. To investigate the differences in lesion site between hemianopic alexia and pure alexia groups, as rehabilitative techniques differ between the two conditions. High-resolution magnetic resonance images were obtained from seven patients with hemianopic alexia and from six patients with pure alexia caused by a left occipital stroke. The boundary of each lesion was defined and lesion volumes were then transformed into a standard stereotactic space so that regional comparisons could be made. The two patient groups did not differ in terms of damage to the medial left occipital lobe, but those with pure alexia had additional lateral damage to the posterior fusiform gyrus and adjacent tissue. Clinicians will be able to predict the type of reading disorder patients with left occipital lesions have from simple tests of reading speed and the distribution of damage to the left occipital lobe on brain imaging. This information will aid management decisions, including recommendations for reading rehabilitation.

  15. PURE conversations: enhancing communication and teamwork.

    PubMed

    Veltman, Larry; Larison, Kristine

    2007-01-01

    Communications failures have been identified as a significant cause of adverse outcomes in obstetrics. Following the lead of some high reliability organizations, healthcare has introduced structured communication such as SBAR as a way to make sure communications between professionals are direct, complete and effective. The authors have observed, however, that structured communication in healthcare often requires a cultural change in the way that professionals relate to each other; PURE conversations (Purposeful/prepared/productive, Unambiguous, Respectful and Effective) can facilitate this cultural shift. PURE conversations stress the mental processes necessary to conduct and monitor structured communications in real time by taking into account the context and relationships that exist among professionals. This article describes the elements of a multidisciplinary workshop based on clinical scenarios incorporating the PURE concept to improve the effectiveness and adoption of structured communication by the perinatal team.

  16. Pure neuritic leprosy: Current status and relevance.

    PubMed

    Rao, P Narasimha; Suneetha, Sujai

    2016-01-01

    Pure neuritic leprosy has always been an enigma due to its clinical and management ambiguities. Although only the Indian Association of Leprologist's classification recognizes 'pure neuritic leprosy' as a distinct sub group of leprosy, cases nonetheless are reported from various countries of Asia, Africa, South America and Europe, indicating its global relevance. It is important to maintain pure neuritic leprosy as a subgroup as it constitutes a good percentage of leprosy cases reported from India, which contributes to more than half of global leprosy numbers. Unfortunately, a high proportion of these patients present with Grade 2 disability at the time of initial reporting itself due to the early nerve involvement. Although skin lesions are absent by definition, when skin biopsies were performed from the skin along the distribution of the affected nerve, a proportion of patients demonstrated leprosy pathology, revealing sub-clinical skin involvement. In addition on follow-up, skin lesions are noted to develop in up to 20% of pure neuritic leprosy cases, indicating its progression to manifest cutaneous disease. Over the decades, the confirmation of diagnosis of pure neuritic leprosy has been subjective, however, with the arrival and use of high-resolution ultrasonography (HRUS) for nerve imaging, we have a tool not only to objectively measure and record the nerve thickening but also to assess the morphological alterations in the nerve including echo texture, fascicular pattern and vascularity. Management of pure neuritic leprosy requires multidrug therapy along with appropriate dose of systemic corticosteroids, for both acute and silent neuritis. Measures for pain relief, self-care of limbs and physiotherapy are important to prevent as well as manage disabilities in this group of patients.

  17. Pure agraphia: a discrete form of aphasia.

    PubMed Central

    Rosati, G; De Bastiani, P

    1979-01-01

    A 62 year old, right handed man developed a pure agraphia as the result of a left temporal lobe stroke. Isolated writing disturbances persisted for seven months until he had a second cerebrovascular accident resulting in total aphasia and right hemiplegia. A CAT scan obtained four months after the first episode showed a localised dilatation of the posterior portion of the left Sylvian cistern and patchy areas of low absorption in the left temporal lobe. The report supports suggestions that localised damage to the language area can produce a pure agraphia as the sole detectable disorder of language organisation. Images PMID:438836

  18. Pure Apraxia of Speech - A Case Report -

    PubMed Central

    Kang, Young Ae; Yun, Sang Jin

    2011-01-01

    Apraxia of speech (AOS) is the impairment of motor programming. However, the exact nature of this deficit remains unclear. In particular, AOS without other speech-language deficit is called pure AOS, but it is very rare. When diagnosing AOS, the characteristic of articulation is considered a crucial criterion, which has been proposed for differentiating AOS from phonological and dysarthric disorders. The present study reports on pure AOS in a 37-year-old right-handed male after a left insular, front, temporal infarction. This report may be useful for further AOS study and diagnosis in the clinical setting. PMID:22506197

  19. BRST and the pure spinor formalism

    SciTech Connect

    Garcia, J. Antonio

    2008-03-06

    The aim of this talk is to show the relation between the standard BRST approach of the GS superstring with the quantization technics used in the pure spinor approach to superstring. To that end we will use the Batalin-Fradkin-Tyutin (BFT) conversion program of second class constraints to first class constraints in the GS superstring using light cone coordinates. By applying this systematic procedure we were able to obtain a gauge system that is equivalent to the recent model proposed in [1] to relate the GS superstring to the pure spinor formalism.

  20. Minimal covariant observables identifying all pure states

    NASA Astrophysics Data System (ADS)

    Carmeli, Claudio; Heinosaari, Teiko; Toigo, Alessandro

    2013-09-01

    It has been recently shown by Heinosaari, Mazzarella and Wolf (2013) [1] that an observable that identifies all pure states of a d-dimensional quantum system has minimally 4d-4 outcomes or slightly less (the exact number depending on d). However, no simple construction of this type of minimal observable is known. We investigate covariant observables that identify all pure states and have minimal number of outcomes. It is shown that the existence of this kind of observables depends on the dimension of the Hilbert space.

  1. Strong nebular line ratios in the spectra of z ∼ 2-3 star forming galaxies: first results from KBSS-MOSFIRE

    SciTech Connect

    Steidel, Charles C.; Rudie, Gwen C.; Strom, Allison L.; Trainor, Ryan F.; Konidaris, Nicholas P.; Matthews, Keith; Pettini, Max; Reddy, Naveen A.; Shapley, Alice E.; Kulas, Kristin R.; Mace, Gregory; McLean, Ian S.; Erb, Dawn K.; Turner, Monica L.

    2014-11-10

    We present initial results of a deep near-IR spectroscopic survey covering the 15 fields of the Keck Baryonic Structure Survey using the recently commissioned MOSFIRE spectrometer on the Keck 1 telescope. We focus on a sample of 251 galaxies with redshifts 2.0 < z < 2.6, star formation rates (SFRs) 2 ≲ SFR ≲ 200 M {sub ☉} yr{sup –1}, and stellar masses 8.6 < log (M {sub *}/M {sub ☉}) < 11.4, with high-quality spectra in both H- and K-band atmospheric windows. We show unambiguously that the locus of z ∼ 2.3 galaxies in the 'BPT' nebular diagnostic diagram exhibits an almost entirely disjointed, yet similarly tight, relationship between the line ratios [N II] λ6585/Hα and [O III]/Hβ as compared to local galaxies. Using photoionization models, we argue that the offset of the z ∼ 2.3 BPT locus relative to that at z ∼ 0 is caused by a combination of harder stellar ionizing radiation field, higher ionization parameter, and higher N/O at a given O/H compared to most local galaxies, and that the position of a galaxy along the z ∼ 2.3 star-forming BPT locus is surprisingly insensitive to gas-phase oxygen abundance. The observed nebular emission line ratios are most easily reproduced by models in which the net stellar ionizing radiation field resembles a blackbody with effective temperature T {sub eff} = 50, 000-60, 000 K, the gas-phase oxygen abundances lie in the range 0.2 < Z/Z {sub ☉} < 1.0, and the ratio of gas-phase N/O is close to the solar value. We critically assess the applicability at high redshift of commonly used strong line indices for estimating gas-phase metallicity, and consider the implications of the small intrinsic scatter of the empirical relationship between excitation-sensitive line indices and M {sub *} (i.e., the 'mass-metallicity' relation) at z ≅ 2.3.

  2. Deciphering the nebular and asteroidal record of silicates and organic material in the matrix of the reduced CV3 chondrite Vigarano

    NASA Astrophysics Data System (ADS)

    Abreu, Neyda M.; Brearley, Adrian J.

    2011-02-01

    We have conducted scanning electron microscope (SEM) and transmission electron microscope (TEM) studies of a variety of occurrences of matrix in the reduced CV3 chondrite breccia Vigarano. Matrix, which occurs as clastic interchondrule material and finer-grained rims, is dominated by morphologically variable olivines that host submicron, hercynitic spinel, and carbonaceous inclusions. Clastic matrix and fine-grained rims show significant differences in their olivine morphologies, abundance, and composition of olivine inclusions, and characteristics of the carbonaceous matter. We suggest that these differences are the result of different degrees of alteration of clastic matrix and rims and are not due to variability in their precursor materials. Textural and compositional characteristics of olivine in the matrix are consistent with formation by growth, possibly from an amorphous precursor material during asteroidal metamorphism, in the presence of limited quantities of aqueous fluids. Spinel inclusions in olivine may be nebular condensates that acted as seeds for nucleation of olivine or may have formed during metamorphism and were subsequently overgrown by olivine. Carbonaceous material occurs as nanometer-sized inclusions within olivine in both fine-grained rims and clastic matrix, but is most abundant as 100-200 nm grains, interstitial to matrix olivines. Most carbonaceous material is amorphous, but poorly graphitized carbon (PGC) also occurs as a minor component in both olivine inclusions and interstitial C. The widespread occurrence of fine-grained amorphous carbon grains in the interstitial regions between olivine grains may preserve the distribution and grain size of nebular organic material. No clear textural relationships exist between carbonaceous grains and the other mineralogical components of Vigarano matrix that could help constrain the origin of the organic grains (i.e., evidence for Fischer-Tropsch-type reactions). Finally, there are considerable

  3. Intrinsic W nucleosynthetic isotope variations in carbonaceous chondrites: Implications for W nucleosynthesis and nebular vs. parent body processing of presolar materials

    NASA Astrophysics Data System (ADS)

    Burkhardt, Christoph; Schönbächler, Maria

    2015-09-01

    not the sole cause for creating the different pattern. Small-scale nebular redistribution of anomalous W may have played a role as well. Similar nebular processes possibly acted differently on specific carrier phases and elements, resulting in the diverse nucleosynthetic signatures observed in planetary materials today.

  4. Strong Nebular Line Ratios in the Spectra of z ~ 2-3 Star Forming Galaxies: First Results from KBSS-MOSFIRE

    NASA Astrophysics Data System (ADS)

    Steidel, Charles C.; Rudie, Gwen C.; Strom, Allison L.; Pettini, Max; Reddy, Naveen A.; Shapley, Alice E.; Trainor, Ryan F.; Erb, Dawn K.; Turner, Monica L.; Konidaris, Nicholas P.; Kulas, Kristin R.; Mace, Gregory; Matthews, Keith; McLean, Ian S.

    2014-11-01

    We present initial results of a deep near-IR spectroscopic survey covering the 15 fields of the Keck Baryonic Structure Survey using the recently commissioned MOSFIRE spectrometer on the Keck 1 telescope. We focus on a sample of 251 galaxies with redshifts 2.0 < z < 2.6, star formation rates (SFRs) 2 <~ SFR <~ 200 M ⊙ yr-1, and stellar masses 8.6 < log (M */M ⊙) < 11.4, with high-quality spectra in both H- and K-band atmospheric windows. We show unambiguously that the locus of z ~ 2.3 galaxies in the "BPT" nebular diagnostic diagram exhibits an almost entirely disjointed, yet similarly tight, relationship between the line ratios [N II] λ6585/Hα and [O III]/Hβ as compared to local galaxies. Using photoionization models, we argue that the offset of the z ~ 2.3 BPT locus relative to that at z ~ 0 is caused by a combination of harder stellar ionizing radiation field, higher ionization parameter, and higher N/O at a given O/H compared to most local galaxies, and that the position of a galaxy along the z ~ 2.3 star-forming BPT locus is surprisingly insensitive to gas-phase oxygen abundance. The observed nebular emission line ratios are most easily reproduced by models in which the net stellar ionizing radiation field resembles a blackbody with effective temperature T eff = 50, 000-60, 000 K, the gas-phase oxygen abundances lie in the range 0.2 < Z/Z ⊙ < 1.0, and the ratio of gas-phase N/O is close to the solar value. We critically assess the applicability at high redshift of commonly used strong line indices for estimating gas-phase metallicity, and consider the implications of the small intrinsic scatter of the empirical relationship between excitation-sensitive line indices and M * (i.e., the "mass-metallicity" relation) at z ~= 2.3. Based on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous

  5. Pure word deafness and pure anarthria in a patient with frontotemporal dementia.

    PubMed

    Iizuka, O; Suzuki, K; Endo, K; Fujii, T; Mori, E

    2007-04-01

    A 66-year-old right-handed man developed pure anarthria following pure word deafness. In addition to language disorders, his behavior gradually changed and finally included violence against his wife. Brain magnetic resonance imagings revealed atrophy of the left perisylvian area, which included the inferior half of the precentral gyrus and the upper portion of the superior temporal gyrus, consistent with frontotemporal dementia (FTD). It has been documented as either a disorder of expressive language or as an impaired understanding of word meaning. Unlike with pure anarthria, pure word deafness is not included in the clinical diagnostic current criteria for FTD. However, a large variety of language symptoms can appear in FTD according to the distribution of pathological changes in the frontotemporal cortices. This case suggests that pure word deafness could be a prodomal symptom of FTD.

  6. Yttria Nanoparticle Reinforced Commercially Pure (CP) Titanium

    DTIC Science & Technology

    2011-09-01

    nanoparticles as well as titanium boride (TiB) reinforcements were produced through gas atomization. After consolidation and extrusion, room temperature...pure FE iron O oxygen Ti titanium TiB titanium boride TYS tensile yield strength UTS ultimate tensile strength wt% weight percent Y2O3

  7. Purely competitive evolutionary dynamics for games.

    PubMed

    Veller, Carl; Rajpaul, Vinesh

    2012-10-01

    We introduce and analyze a purely competitive dynamics for the evolution of an infinite population subject to a three-strategy game. We argue that this dynamics represents a characterization of how certain systems, both natural and artificial, are governed. In each period, the population is randomly sorted into pairs, which engage in a once-off play of the game; the probability that a member propagates its type to its offspring is proportional only to its payoff within the pair. We show that if a type is dominant (obtains higher payoffs in games with both other types), its "pure" population state, comprising only members of that type, is globally attracting. If there is no dominant type, there is an unstable "mixed" fixed point; the population state eventually oscillates between the three near-pure states. We then allow for mutations, where offspring have a nonzero probability of randomly changing their type. In this case, the existence of a dominant type renders a point near its pure state globally attracting. If no dominant type exists, a supercritical Hopf bifurcation occurs at the unique mixed fixed point, and above a critical (typically low) mutation rate, this fixed point becomes globally attracting: the implication is that even very low mutation rates can stabilize a system that would, in the absence of mutations, be unstable.

  8. Implicit Reading in Chinese Pure Alexia

    ERIC Educational Resources Information Center

    Shan, Chunlei; Zhu, Renjing; Xu, Mingwei; Luo, Benyan; Weng, Xuchu

    2010-01-01

    A number of recent studies have shown that some patients with pure alexia display evidence of implicit access to lexical and semantic information about words that they cannot read explicitly. This phenomenon has not been investigated systematically in Chinese patients. We report here a case study of a Chinese patient who met the criteria for pure…

  9. Pure science and the problem of progress.

    PubMed

    Douglas, Heather

    2014-06-01

    How should we understand scientific progress? Kuhn famously discussed science as its own internally driven venture, structured by paradigms. He also famously had a problem describing progress in science, as problem-solving ability failed to provide a clear rubric across paradigm change--paradigm changes tossed out problems as well as solving them. I argue here that much of Kuhn's inability to articulate a clear view of scientific progress stems from his focus on pure science and a neglect of applied science. I trace the history of the distinction between pure and applied science, showing how the distinction came about, the rhetorical uses to which the distinction has been put, and how pure science came to be both more valued by scientists and philosophers. I argue that the distinction between pure and applied science does not stand up to philosophical scrutiny, and that once we relinquish it, we can provide Kuhn with a clear sense of scientific progress. It is not one, though, that will ultimately prove acceptable. For that, societal evaluations of scientific work are needed.

  10. Primary pure choriocarcinoma of the liver.

    PubMed

    Fernández Alonso, J; Sáez, C; Pérez, P; Montaño, A; Japón, M A

    1992-04-01

    We report a pure choriocarcinoma of the liver studied at necropsy. The tumour was diagnosed ante-mortem and treated by chemotherapy with no satisfactory response. Previous cases of hepatic choriocarcinoma are reviewed and criteria to diagnose this extragonadal neoplasm are recommended.

  11. Pure Dephasing of a Vibrational Adbond.

    DTIC Science & Technology

    1987-08-01

    that pure dephasing terms Involve only one (real) level of the adbond, and that sIngle-phonon proceses are Impossible. Figure 4. The logarithm of the...Crane, Indiana 47522-5050 China Lake, California 93555 Scientific Advisor Naval Civil Engineering Laboratory 1 Commandant of the Marine Corps Attn: Dr. R

  12. Implicit Reading in Chinese Pure Alexia

    ERIC Educational Resources Information Center

    Shan, Chunlei; Zhu, Renjing; Xu, Mingwei; Luo, Benyan; Weng, Xuchu

    2010-01-01

    A number of recent studies have shown that some patients with pure alexia display evidence of implicit access to lexical and semantic information about words that they cannot read explicitly. This phenomenon has not been investigated systematically in Chinese patients. We report here a case study of a Chinese patient who met the criteria for pure…

  13. Predict thermal conductivities of pure gases

    SciTech Connect

    Weber, J.H.

    1981-01-01

    The programs presented for the TI-59 programmable calculator can determine the thermal conductivity of pure gases and gases at low pressures as well as the effect of pressure on conductivity. They are based on correlations by Eucken, Stiel-Thodos, Misic-Thodos, Roy-Thodos, and Redlich-Kwong.

  14. Constraints on nebular dynamics and chemistry based on observations of annealed magnesium silicate grains in comets and in disks surrounding Herbig Ae/Be stars

    PubMed Central

    Hill, Hugh G. M.; Grady, Carol A.; Nuth, Joseph A.; Hallenbeck, Susan L.; Sitko, Michael L.

    2001-01-01

    Understanding dynamic conditions in the Solar Nebula is the key to prediction of the material to be found in comets. We suggest that a dynamic, large-scale circulation pattern brings processed dust and gas from the inner nebula back out into the region of cometesimal formation—extending possibly hundreds of astronomical units (AU) from the sun—and that the composition of comets is determined by a chemical reaction network closely coupled to the dynamic transport of dust and gas in the system. This scenario is supported by laboratory studies of Mg silicates and the astronomical data for comets and for protoplanetary disks associated with young stars, which demonstrate that annealing of nebular silicates must occur in conjunction with a large-scale circulation. Mass recycling of dust should have a significant effect on the chemical kinetics of the outer nebula by introducing reduced, gas-phase species produced in the higher temperature and pressure environment of the inner nebula, along with freshly processed grains with “clean” catalytic surfaces to the region of cometesimal formation. Because comets probably form throughout the lifetime of the Solar Nebula and processed (crystalline) grains are not immediately available for incorporation into the first generation of comets, an increasing fraction of dust incorporated into a growing comet should be crystalline olivine and this fraction can serve as a crude chronometer of the relative ages of comets. The formation and evolution of key organic and biogenic molecules in comets are potentially of great consequence to astrobiology. PMID:11226213

  15. Chemical and physical studies of chondrites: 10. Cathodoluminescence and phase composition studies of metamorphism and nebular processes in chondrules of type 3 ordinary chondrites

    SciTech Connect

    DeHart, J.M.; Lu Jie; Benoit, P.H.; Sears, D.W.G. ); Lofgren, G.E. )

    1992-10-01

    The cathodoluminescence (CL) properties of eight type 3 ordinary chondrites and one L5 chondrite have been determined, and phenocryst and mesostasis compositions have been analyzed in the chondrules of four of them (Semarkona, type 3.0; Krymka, 3.1; Allan Hills A77214, 3.5; and Dhajala, 3.8) in order to investigate their origins and metamorphic history. In the present study, the authors discuss the CL properties of nine ordinary chondrites of a variety of petrologic types with particular emphasis on detailed studies of the compositions of the relevant phases in four of these: Semarkona (3.0), Krymka (3.1), Allan Hills A77214 (3.5), and Dhajala (3.8). They describe a means of classifying chondrules that is based on the composition of their two major components, the mesostasis and phenocrysts. The system is applicable to > 90-95% off the chondrules in a given meteorite and it describes the range of material produced by nebular material and of the effect of metamorphism on the chondrules. They also discuss the relevance of the results for the origin of the nine chondrite classes.

  16. Pure Air`s Bailly scrubber: A four-year retrospective

    SciTech Connect

    Manavi, G.B.; Vymazal, D.C.; Sarkus, T.A.

    1997-12-31

    Pure Air`s Advanced Flue Gas Desulfurization (AFGD) Clean Coal Project has completed four highly successful years of operation at NIPSCO`s Bailly Station. As part of their program, Pure Air has concluded a six-part study of system performance. This paper summarizes the results of the demonstration program, including AFGD performance on coals ranging from 2.0--2.4% sulfur. The paper highlights novel aspects of the Bailly facility, including pulverized limestone injection, air rotary sparger for oxidation, wastewater evaporation system and the production of PowerChip{reg_sign} gypsum. Operations and maintenance which have led to the facility`s notable 99.47% availability record are also discussed. A project company, Pure Air on the Lake Limited Partnership, owns the AFGD facility. Pure Air was the turn key contractor and Air Products and Chemicals, Inc. is the operator of the AFGD system.

  17. High Strength, Large Core Pure Silica Fibers For Laser Surgery

    NASA Astrophysics Data System (ADS)

    Skutnik, B. J.; Hodge, M. H.; Clarkin, J. P.

    1988-06-01

    Recently many researchers, doctors and instrument companies have begun developing fiber optic laser power delivery systems to accomplish less traumatic surgery or localized irradiation treatment(1). With high power levels, particularly in short bursts, large core fibers are needed to keep the power densities from approaching the damage threshold of silica. Among the many advantages of using optical fibers in laser surgery are the following: microsurgery can be employed, trauma is reduced, access to interior through catheter introduction into vascular, gastrointestinal or respiratory tracts, accurate application of laser power through a flexible lightweight medium to provide localized irradiation as well as surgical removal, and the devices are sterilizable and of moderate cost permitting one-time use (disposable) probes. To achieve these wonderful gains in surgical procedures, the optical fibers must satisfy many optical and mechanical requirements. In use the optical fibers are often required to bend around curves or obstructions to reach the desired application area. Large tensile stresses can occur on the outer radius of the bent fiber, especially with large core fibers, thus high strength fibers are needed. Furthermore, since body fluids are primarily water, stress corrosion and fatigue(2-6) will occur. Therefore, the fibers should have excellent fatigue resistance as well as high strength. This paper further describes these requirements and presents details about an optical fiber which meets these requirements and provides additional very useful properties. These fibers with pure silica cores are called Hard Clad Silica, HCS*, fibers because of their hard bonded cladding over silica structure.

  18. 7 CFR 201.64 - Pure live seed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Pure live seed. 201.64 Section 201.64 Agriculture... REGULATIONS Tolerances § 201.64 Pure live seed. The tolerance for pure live seed shall be determined by applying the respective tolerances to the germination plus the hard seed and the pure seed....

  19. 7 CFR 201.64 - Pure live seed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Pure live seed. 201.64 Section 201.64 Agriculture... REGULATIONS Tolerances § 201.64 Pure live seed. The tolerance for pure live seed shall be determined by applying the respective tolerances to the germination plus the hard seed and the pure seed....

  20. 7 CFR 201.64 - Pure live seed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Pure live seed. 201.64 Section 201.64 Agriculture... REGULATIONS Tolerances § 201.64 Pure live seed. The tolerance for pure live seed shall be determined by applying the respective tolerances to the germination plus the hard seed and the pure seed. [5 FR 35,...

  1. 7 CFR 201.64 - Pure live seed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Pure live seed. 201.64 Section 201.64 Agriculture... REGULATIONS Tolerances § 201.64 Pure live seed. The tolerance for pure live seed shall be determined by applying the respective tolerances to the germination plus the hard seed and the pure seed....

  2. 7 CFR 201.64 - Pure live seed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Pure live seed. 201.64 Section 201.64 Agriculture... REGULATIONS Tolerances § 201.64 Pure live seed. The tolerance for pure live seed shall be determined by applying the respective tolerances to the germination plus the hard seed and the pure seed. [5 FR 35,...

  3. Heat engine driven by purely quantum information.

    PubMed

    Park, Jung Jun; Kim, Kang-Hwan; Sagawa, Takahiro; Kim, Sang Wook

    2013-12-06

    The key question of this Letter is whether work can be extracted from a heat engine by using purely quantum mechanical information. If the answer is yes, what is its mathematical formula? First, by using a bipartite memory we show that the work extractable from a heat engine is bounded not only by the free energy change and the sum of the entropy change of an individual memory but also by the change of quantum mutual information contained inside the memory. We then find that the engine can be driven by purely quantum information, expressed as the so-called quantum discord, forming a part of the quantum mutual information. To confirm it, as a physical example we present the Szilard engine containing a diatomic molecule with a semipermeable wall.

  4. Black Hole Attractors and Pure Spinors

    SciTech Connect

    Hsu, Jonathan P.; Maloney, Alexander; Tomasiello, Alessandro

    2006-02-21

    We construct black hole attractor solutions for a wide class of N = 2 compactifications. The analysis is carried out in ten dimensions and makes crucial use of pure spinor techniques. This formalism can accommodate non-Kaehler manifolds as well as compactifications with flux, in addition to the usual Calabi-Yau case. At the attractor point, the charges fix the moduli according to {Sigma}f{sub k} = Im(C{Phi}), where {Phi} is a pure spinor of odd (even) chirality in IIB (A). For IIB on a Calabi-Yau, {Phi} = {Omega} and the equation reduces to the usual one. Methods in generalized complex geometry can be used to study solutions to the attractor equation.

  5. Pure field theories and MACSYMA algorithms

    NASA Technical Reports Server (NTRS)

    Ament, W. S.

    1977-01-01

    A pure field theory attempts to describe physical phenomena through singularity-free solutions of field equations resulting from an action principle. The physics goes into forming the action principle and interpreting specific results. Algorithms for the intervening mathematical steps are sketched. Vacuum general relativity is a pure field theory, serving as model and providing checks for generalizations. The fields of general relativity are the 10 components of a symmetric Riemannian metric tensor; those of the Einstein-Straus generalization are the 16 components of a nonsymmetric. Algebraic properties are exploited in top level MACSYMA commands toward performing some of the algorithms of that generalization. The light cone for the theory as left by Einstein and Straus is found and simplifications of that theory are discussed.

  6. How Pure Components Control Polymer Blend Miscibility

    NASA Astrophysics Data System (ADS)

    White, Ronald; Lipson, Jane; Higgins, Julia

    2012-02-01

    We present insight into some intriguing relationships revealed by our recent studies of polymer mixture miscibility. Applying our simple lattice-based equation of state, we discuss some of the patterns observed over a sample of experimental blends. We focus on the question of how much key information can one determine from a knowledge of just the pure components only, and further, on the role of separate enthalpic and entropic contributions to the miscibility behavior. One interesting correlation connects the value of the difference in pure component energetic parameters with that of the mixed segment interactions, suggesting new possibilities for predictive modeling. We also show how in some cases these two parameter groupings act as separate controls determining the entropy and enthalpy of mixing. Also discussed are the different patterns exhibited for UCST-type and LCST-type blends, these being revealed in some cases by simple examination of the underlying microscopic parameters.

  7. Physics with chemically and isotopically pure semiconductors

    SciTech Connect

    Haller, E.E.

    1993-05-01

    Chemically and isotopically pure semiconductors offer a wealth of interesting physics. We review a number of impurity complexes which were discovered in ultrapure Germanium. The have led the way to the widely pursued studies of hydrogen in numerous semiconductors. Isotope related effects and processes include neutron transmutation doping, a technique used for a number of silicon and germanium devices. Isotopically pure and deliberately mixed crystals of germanium have been grown recently and have been used to study the dependence of the indirect bandgap and phonon properties on the mass and mass disorder of the nuclei. The large number of stable isotopes of the various semiconductors present a great potential for basic and applied studies. Semi-conductor isotope engineering may become a reality because of the new economic and political world order.

  8. Physics with chemically and isotopically pure semiconductors

    NASA Astrophysics Data System (ADS)

    Haller, E. E.

    1993-05-01

    Chemically and isotopically pure semiconductors offer a wealth of interesting physics. We review a number of impurity complexes which were discovered in ultrapure Germanium. They have led the way to the widely pursued studies of hydrogen in numerous semiconductors. Isotope related effects and processes include neutron transmutation doping, a technique used for a number of silicon and germanium devices. Isotopically pure and deliberately mixed crystals of germanium have been grown recently and have been used to study the dependence of the indirect bandgap and phonon properties on the mass and mass disorder of the nuclei. The large number of stable isotopes of the various semiconductors present a great potential for basic and applied studies. Semi-conductor isotope engineering may become a reality because of the new economic and political world order.

  9. Pure field theories and MACSYMA algorithms

    NASA Technical Reports Server (NTRS)

    Ament, W. S.

    1977-01-01

    A pure field theory attempts to describe physical phenomena through singularity-free solutions of field equations resulting from an action principle. The physics goes into forming the action principle and interpreting specific results. Algorithms for the intervening mathematical steps are sketched. Vacuum general relativity is a pure field theory, serving as model and providing checks for generalizations. The fields of general relativity are the 10 components of a symmetric Riemannian metric tensor; those of the Einstein-Straus generalization are the 16 components of a nonsymmetric. Algebraic properties are exploited in top level MACSYMA commands toward performing some of the algorithms of that generalization. The light cone for the theory as left by Einstein and Straus is found and simplifications of that theory are discussed.

  10. Computing Properties Of Pure And Mixed Fluids

    NASA Technical Reports Server (NTRS)

    Fowler, J. R.; Hendricks, Robert C.

    1993-01-01

    GASPLUS created as two-part code: first designed for use with pure fluids and second designed for use with mixtures of fluids and phases. Offers routines for mathematical modeling of conditions of fluids in pumps, turbines, compressors and other machines. Other routines for calculating performance of para/ortho-hydrogen reactor and heat of para/normal-hydrogen reaction as well as unique convergence routine demonstrates engineering flavor of GASPLUS. Written in FORTRAN 77.

  11. Pure connection action principle for general relativity.

    PubMed

    Krasnov, Kirill

    2011-06-24

    It has already been known for two decades that general relativity can be reformulated as a certain gauge theory, so that the only dynamical field is an SO(3) connection and the spacetime metric appears as a derived object. However, no simple action principle realizing these ideas has been available. A new elegant action principle for such a "pure connection" formulation of GR is described.

  12. Computing Properties Of Pure And Mixed Fluids

    NASA Technical Reports Server (NTRS)

    Fowler, J. R.; Hendricks, Robert C.

    1993-01-01

    GASPLUS created as two-part code: first designed for use with pure fluids and second designed for use with mixtures of fluids and phases. Offers routines for mathematical modeling of conditions of fluids in pumps, turbines, compressors and other machines. Other routines for calculating performance of para/ortho-hydrogen reactor and heat of para/normal-hydrogen reaction as well as unique convergence routine demonstrates engineering flavor of GASPLUS. Written in FORTRAN 77.

  13. Les Problemes de l'alexie pure (Problems of Pure Alexia)

    ERIC Educational Resources Information Center

    Kremin, Helgard

    1976-01-01

    This article reviews studies done on alexia and describes experiments designed to distinguish qualitatively between pure alexia (marked by the absence of oral and written problems) and other forms of alexia. (Text is in French.) (CLK)

  14. On constructing purely affine theories with matter

    NASA Astrophysics Data System (ADS)

    Cervantes-Cota, Jorge L.; Liebscher, D.-E.

    2016-08-01

    We explore ways to obtain the very existence of a space-time metric from an action principle that does not refer to it a priori. Although there are reasons to believe that only a non-local theory can viably achieve this goal, we investigate here local theories that start with Schrödinger's purely affine theory (Schrödinger in Space-time structure. Cambridge UP, Cambridge, 1950), where he gave reasons to set the metric proportional to the Ricci curvature aposteriori. When we leave the context of unified field theory, and we couple the non-gravitational matter using some weak equivalence principle, we can show that the propagation of shock waves does not define a lightcone when the purely affine theory is local and avoids the explicit use of the Ricci tensor in realizing the weak equivalence principle. When the Ricci tensor is substituted for the metric, the equations seem to have only a very limited set of solutions. This backs the conviction that viable purely affine theories have to be non-local.

  15. Graphical calculus for Gaussian pure states

    SciTech Connect

    Menicucci, Nicolas C.; Flammia, Steven T.; Loock, Peter van

    2011-04-15

    We provide a unified graphical calculus for all Gaussian pure states, including graph transformation rules for all local and semilocal Gaussian unitary operations, as well as local quadrature measurements. We then use this graphical calculus to analyze continuous-variable (CV) cluster states, the essential resource for one-way quantum computing with CV systems. Current graphical approaches to CV cluster states are only valid in the unphysical limit of infinite squeezing, and the associated graph transformation rules only apply when the initial and final states are of this form. Our formalism applies to all Gaussian pure states and subsumes these rules in a natural way. In addition, the term 'CV graph state' currently has several inequivalent definitions in use. Using this formalism we provide a single unifying definition that encompasses all of them. We provide many examples of how the formalism may be used in the context of CV cluster states: defining the 'closest' CV cluster state to a given Gaussian pure state and quantifying the error in the approximation due to finite squeezing; analyzing the optimality of certain methods of generating CV cluster states; drawing connections between this graphical formalism and bosonic Hamiltonians with Gaussian ground states, including those useful for CV one-way quantum computing; and deriving a graphical measure of bipartite entanglement for certain classes of CV cluster states. We mention other possible applications of this formalism and conclude with a brief note on fault tolerance in CV one-way quantum computing.

  16. Reflection on Teaching and Epistemological Structure: Reflective and Critically Reflective Processes in "Pure/Soft" and "Pure/Hard" Fields

    ERIC Educational Resources Information Center

    Kreber, Carolin; Castleden, Heather

    2009-01-01

    We empirically explored whether academics from pure/soft and pure/hard fields engage in reflective practice on teaching differently and, if so, whether these differences could be partially explained by the epistemological structure of their discipline. Interview data from academics in pure/hard (N = 30) and pure/soft fields (N = 10) were…

  17. The Expanding Nebular Remnant of the Recurrent Nova RS Ophiuchi (2006). II. Modeling of Combined Hubble Space Telescope Imaging and Ground-based Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ribeiro, V. A. R. M.; Bode, M. F.; Darnley, M. J.; Harman, D. J.; Newsam, A. M.; O'Brien, T. J.; Bohigas, J.; Echevarría, J. M.; Bond, H. E.; Chavushyan, V. H.; Costero, R.; Coziol, R.; Evans, A.; Eyres, S. P. S.; León-Tavares, J.; Richer, M. G.; Tovmassian, G.; Starrfield, S.; Zharikov, S. V.

    2009-10-01

    We report Hubble Space Telescope (HST) imaging, obtained 155 and 449 days after the 2006 outburst of the recurrent nova RS Ophiuchi, together with ground-based spectroscopic observations, obtained from the Observatorio Astronómico Nacional en San Pedro Mártir, Baja California, México and at the Observatorio Astrofísico Guillermo Haro, at Cananea, Sonora, México. The observations at the first epoch were used as inputs to model the geometry and kinematic structure of the evolving RS Oph nebular remnant. We find that the modeled remnant comprises two distinct co-aligned bipolar components; a low-velocity, high-density innermost (hour glass) region and a more extended, high-velocity (dumbbell) structure. This overall structure is in agreement with that deduced from radio observations and optical interferometry at earlier epochs. We find that the asymmetry observed in the west lobe is an instrumental effect caused by the profile of the HST filter and hence demonstrate that this lobe is approaching the observer. We then conclude that the system has an inclination to the line of sight of 39+1°-10. This is in agreement with the inclination of the binary orbit and lends support to the proposal that this morphology is due to the interaction of the outburst ejecta with either an accretion disk around the central white dwarf and/or a pre-existing red giant wind that is significantly denser in the equatorial regions of the binary than at the poles. The second epoch HST observation was also modeled. However, as no spectra were taken at this epoch, it is more difficult to constrain any model. Nevertheless, we demonstrate that between the two HST epochs the outer dumbbell structure seems to have expanded linearly. For the central (hour glass) region, there may be evidence of deceleration, but it is harder to draw firm conclusions in this case.

  18. Single passive direct methanol fuel cell supplied with pure methanol

    NASA Astrophysics Data System (ADS)

    Feng, Ligang; Zhang, Jing; Cai, Weiwei; Liang, Liang; Xing, Wei; Liu, Changpeng

    2011-03-01

    A new single passive direct methanol fuel cell (DMFC) supplied with pure methanol is designed, assembled and tested using a pervaporation membrane (PM) to control the methanol transport. The effect of the PM size on the fuel cell performances and the constant current discharge of the fuel cell with one-fueling are studied. The results show that the fuel cell with PM 9 cm2 can yield a maximum power density of about 21 mW cm-2, and a stable performances at a discharge current of 100 mA can last about 45 h. Compared with DMFC supplied with 3 M methanol solution, the energy density provided by this new DMFC has increased about 6 times.

  19. Hippocampal body changes in pure partial onset sleep and pure partial onset waking epileptic patients.

    PubMed

    Motamedi, Mahmood; Zandieh, Ali; Hajimirzabeigi, Alireza; Tahsini, Majid; Vakhshiteh, Fatemeh; Rahimian, Elham

    2013-09-01

    The aim of the current study was to evaluate for the first time the hippocampal changes in patients with pure sleep and pure waking epilepsy. A total of 35 patients with pure partial onset sleep epilepsy and 35 patients with pure partial onset waking epilepsy matched for age and sex ratio were enrolled. MR images were analyzed to determine hippocampal body changes. Rounding ratio of hippocampal body was defined as short axis divided by long axis and hippocampal bodies with ratios ≥ 0.70 were considered rounded. Hippocampal sclerosis and atrophy were found in nine (25.7 %) and seven (20.0 %) patients with pure sleep epilepsy, and in 12 (34.3 %) and 11 (31.4 %) patients with pure waking epilepsy, respectively (P > 0.05 for the comparison between sleep and waking epilepsy). However, proportion of subjects with rounded hippocampal bodies (15, 42.9 % vs. 3, 8.6 % for patients with sleep and waking epilepsy, respectively) and rounding ratios of both left and right hippocampal bodies (0.66 ± 0.13 and 0.61 ± 0.12, respectively for left and right hippocampal bodies in sleep epileptic patients vs. 0.57 ± 0.11 and 0.55 ± 0.11, respectively for left and right hippocampal bodies in waking epileptic patients) were increased in patients with sleep epilepsy (P < 0.05). Further, in sleep epileptic patients with left sided hippocampal body rounding, epileptiform discharges were more readily lateralized to the left temporal lobe (P < 0.05). In conclusion, hippocampal sclerosis and atrophy are not different between pure partial onset sleep and waking epileptic patients. However, rounding ratio and frequency of hippocampal body rounding are increased in sleep epileptic patients.

  20. THE OPTICAL STRUCTURE OF THE STARBURST GALAXY M82. II. NEBULAR PROPERTIES OF THE DISK AND INNER WIND

    SciTech Connect

    Westmoquette, M. S.; Smith, L. J.; Konstantopoulos, I. S.; Gallagher, J. S.; Trancho, G.

    2009-12-01

    In this second paper of the series, we present the results from optical Gemini-North GMOS-IFU and WIYN DensePak IFU spectroscopic observations of the starburst and inner wind zones of M82, with a focus on the state of the T approx 10{sup 4} K ionized interstellar medium. Our electron density maps show peaks of a few 1000 cm{sup -3} (implying very high thermal pressures), local small spatial-scale variations, and a falloff in the minor axis direction. We discuss the implications of these results with regards to the conditions/locations that may favor the escape of individual cluster winds that ultimately power the large-scale superwind. Our findings, when combined with the body of literature built up over the last decade on the state of the interstellar medium (ISM) in M82, imply that the starburst environment is highly fragmented into a range of clouds from small/dense clumps with low-filling factors (<1 pc, n {sub e} approx> 10{sup 4} cm{sup -3}) to larger filling factor, less dense gas. The most compact clouds seem to be found in the cores of the star cluster complexes, whereas the cloud sizes in the inter-complex region are larger. These dense clouds are bathed with an intense radiation field and embedded in an extensive high temperature (T approx> 10{sup 6} K), X-ray-emitting ISM that is a product of the high star formation rates in the starburst zones of M82. The near-constant state of the ionization state of the approx10{sup 4} K gas throughout the M82 starburst zone can be explained as a consequence of the small cloud sizes, which allow the gas conditions to respond quickly to any changes. In Paper I, we found that the observed emission lines are composed of multiple components, including a broad (FWHM approx 150-350 km s{sup -1}) feature that we associate with emission from turbulent mixing layers on the surfaces of the gas clouds, resulting from the interaction of the fast wind outflows from the synchrotron self-Comptons. The large number of compact clouds

  1. chemf: A purely functional chemistry toolkit.

    PubMed

    Höck, Stefan; Riedl, Rainer

    2012-12-20

    Although programming in a type-safe and referentially transparent style offers several advantages over working with mutable data structures and side effects, this style of programming has not seen much use in chemistry-related software. Since functional programming languages were designed with referential transparency in mind, these languages offer a lot of support when writing immutable data structures and side-effects free code. We therefore started implementing our own toolkit based on the above programming paradigms in a modern, versatile programming language. We present our initial results with functional programming in chemistry by first describing an immutable data structure for molecular graphs together with a couple of simple algorithms to calculate basic molecular properties before writing a complete SMILES parser in accordance with the OpenSMILES specification. Along the way we show how to deal with input validation, error handling, bulk operations, and parallelization in a purely functional way. At the end we also analyze and improve our algorithms and data structures in terms of performance and compare it to existing toolkits both object-oriented and purely functional. All code was written in Scala, a modern multi-paradigm programming language with a strong support for functional programming and a highly sophisticated type system. We have successfully made the first important steps towards a purely functional chemistry toolkit. The data structures and algorithms presented in this article perform well while at the same time they can be safely used in parallelized applications, such as computer aided drug design experiments, without further adjustments. This stands in contrast to existing object-oriented toolkits where thread safety of data structures and algorithms is a deliberate design decision that can be hard to implement. Finally, the level of type-safety achieved by Scala highly increased the reliability of our code as well as the productivity of

  2. chemf: A purely functional chemistry toolkit

    PubMed Central

    2012-01-01

    Background Although programming in a type-safe and referentially transparent style offers several advantages over working with mutable data structures and side effects, this style of programming has not seen much use in chemistry-related software. Since functional programming languages were designed with referential transparency in mind, these languages offer a lot of support when writing immutable data structures and side-effects free code. We therefore started implementing our own toolkit based on the above programming paradigms in a modern, versatile programming language. Results We present our initial results with functional programming in chemistry by first describing an immutable data structure for molecular graphs together with a couple of simple algorithms to calculate basic molecular properties before writing a complete SMILES parser in accordance with the OpenSMILES specification. Along the way we show how to deal with input validation, error handling, bulk operations, and parallelization in a purely functional way. At the end we also analyze and improve our algorithms and data structures in terms of performance and compare it to existing toolkits both object-oriented and purely functional. All code was written in Scala, a modern multi-paradigm programming language with a strong support for functional programming and a highly sophisticated type system. Conclusions We have successfully made the first important steps towards a purely functional chemistry toolkit. The data structures and algorithms presented in this article perform well while at the same time they can be safely used in parallelized applications, such as computer aided drug design experiments, without further adjustments. This stands in contrast to existing object-oriented toolkits where thread safety of data structures and algorithms is a deliberate design decision that can be hard to implement. Finally, the level of type-safety achieved by Scala highly increased the reliability of our code

  3. Electrostatic Precipitation in Nearly Pure Gaseous Nitrogen

    NASA Technical Reports Server (NTRS)

    Buhler, Charles; Calle, Carlos; Clements, Sid; Cox, Bobby; Ritz, Mindy

    2008-01-01

    Electrostatic precipitation was performed in a nearly pure gaseous nitrogen system as a possible remedy for black dust contaminant from high pressure 6000 psi lines at the NASA Kennedy Space Center. The results of a prototype electrostatic precipitator that was built and tested using nitrogen gas at standard atmospheric pressures is presented. High voltage pulsed waveforms are generated using a rotating spark gap system at 30 Hz. A unique dust delivery system utilizing the Venturi effect was devised that supplies a given amount of dust per unit time for testing purposes.

  4. Purely cubic action for string field theory

    NASA Technical Reports Server (NTRS)

    Horowitz, G. T.; Lykken, J.; Rohm, R.; Strominger, A.

    1986-01-01

    It is shown that Witten's (1986) open-bosonic-string field-theory action and a closed-string analog can be written as a purely cubic interaction term. The conventional form of the action arises by expansion around particular solutions of the classical equations of motion. The explicit background dependence of the conventional action via the Becchi-Rouet-Stora-Tyutin operator is eliminated in the cubic formulation. A closed-form expression is found for the full nonlinear gauge-transformation law.

  5. Critical speeding up in pure fluids

    NASA Technical Reports Server (NTRS)

    Boukari, Hacene; Shaumeyer, J. N.; Briggs, Matthew E.; Gammon, Robert W.

    1990-01-01

    The extreme compressibility of a pure fluid near its critical point significantly affects its bulk dynamic response to temperature changes through adiabatic processes. Equations that describe the dynamics in the absence of gravity are developed, and the magnitude of the effect is illustrated with numerical solutions in one dimension. The results are remarkable: 5 mm of critical xenon, quenched from 20 to 10 mK above its critical temperature, cools by over 99 percent in less than 5 s. Moreover, adiabatic cooling is faster when the fluid is closer to the critical point.

  6. Hydroxyl X2Pi pure rotational transitions

    NASA Technical Reports Server (NTRS)

    Goorvitch, D.; Goldman, A.; Dothe, Hoang; Tipping, R. H.; Chackerian, C., Jr.

    1992-01-01

    We present a list of frequencies, term values, Einstein A values, and assignments for the pure rotational transitions of the X2Pi state of the OH molecule. This list includes transitions from 3 to 2015/cm for Delta-v = 0, v-double-prime = 0-4, and J-double-prime = 0.5-49.5. The A values were computed using recent advances in calculating wave functions for a coupled system and an experimentally derived electric dipole moment function (Nelson et al., 1990) which exhibits curvature.

  7. Stress induced hypotension in pure autonomic failure

    PubMed Central

    Thijs, R D; van Dijk, J G

    2006-01-01

    A 47 year old woman with pure autonomic failure complained of dizziness during emotional stress. Emotional stimuli have not previously been reported to cause hypotension in patients with autonomic failure. In the patient, ambulatory blood pressure recording revealed severe hypotension (50/30 mm Hg) after a stressful event. During a tilt table test, hyperventilation was shown to cause a significant fall of blood pressure. This suggests that emotional stress can induce hypotension, probably through hyperventilation, in subjects with autonomic failure. PMID:16354738

  8. Needleless Electrospinning of Pure and Blended Chitosan

    NASA Astrophysics Data System (ADS)

    Grimmelsmann, Nils; Homburg, Sarah Vanessa; Ehrmann, Andrea

    2017-08-01

    Chitosan is a biopolymer with bactericidal, fungicidal, hemostatic and other interesting properties. It can be used, e.g., in medical products, as a filter medium, in biotechnological purposes etc. For these possible applications, nanofiber mats with a large inner surface will be most efficient. This is why in a recent project, the electrospinning properties of pure chitosan as well as chitosan blended with poly(ethylene oxide) were investigated. Using a needleless nanospinning process, the technology under examination can be upscaled from lab to industrial scale, enabling direct transfer of the gained experiences to the intended application.

  9. Pure phase decoherence in a ring geometry

    SciTech Connect

    Zhu, Z.; Aharony, A.; Entin-Wohlman, O.; Stamp, P. C. E.

    2010-06-15

    We study the dynamics of pure phase decoherence for a particle hopping around an N-site ring, coupled both to a spin bath and to an Aharonov-Bohm flux which threads the ring. Analytic results are found for the dynamics of the influence functional and of the reduced density matrix of the particle, both for initial single wave-packet states, and for states split initially into two separate wave packets moving at different velocities. We also give results for the dynamics of the current as a function of time.

  10. Noble gases in pure lipid membranes.

    PubMed

    Sierra-Valdez, F J; Ruiz-Suárez, J C

    2013-03-21

    The mechanism of how a noble gas modifies the excitability of nerve cells and how such excitability can be recovered under hyperbaric pressure remains unclear. Here we present a calorimetric study where the melting point depression of pure lipid membranes induced by noble gases and its recovery with a hydrostatic pressure is addressed. A correlation is found between the electric polarizability (α) of these gases and their effect on the melting transition of the membranes. These results concur with other findings to support the idea that general anesthesia only depends on the ability of a certain atom or molecule to increase the general disorder of the membrane.

  11. PURE CULTURES OF LARGE MONONUCLEAR LEUCOCYTES

    PubMed Central

    Carrel, Alexis; Ebeling, Albert H.

    1922-01-01

    1. Pure strains of mononuclear leucocytes were isolated from the blood of adult chickens and keptin active condition for nearly 3 months. 2. The cultures were composed of large mononuclear leucocytes which migrated and proliferated in vitro at a slower rate than fibroblasts. The cells had no tendency to form a tissue, as do fibroblasts and epithelial cells. They were much less resistant than fibroblasts. 3. Differentiation of the large mononuclears into cells assuming the appearance of fibroblasts took place under certain conditions. 4. The activity of the large mononuclears was increased by embryonic tissue juice and inhibited by homologous serum. PMID:19868678

  12. Pure perceptual-based sequence learning.

    PubMed

    Remillard, Gilbert

    2003-07-01

    Learning a sequence of target locations when the sequence is uncorrelated with a sequence of responses and target location is not the response dimension (pure perceptual-based sequence learning) was examined. Using probabilistic sequences of target locations, the author shows that such learning can be implicit, is unaffected by distance between target locations, and is mostly limited to first-order transition probabilities. Moreover, the mechanism underlying learning affords processing of information at anticipated target locations and appears to be attention based. Implications for hypotheses of implicit sequence learning are discussed.

  13. [XX 'pure' gonadal dysgenesis and XYY syndrome].

    PubMed

    Itoh, Naoki; Tsukamoto, Taiji

    2004-02-01

    XX 'pure' gonadal dysgenesis is a disease related to Turner's syndrome. Patients of this disease are characterized by normal female external genitalia, bilateral streak gonads, amenorrhea and sexual infantilism. Recently, it has been reported that point mutations of the FSH receptor gene may be one of cause of this disease. The relationship between criminal behavior and XYY syndrome is still controversial. Increased incidence of disomic sperm in 47,XYY males has been reported by fluorescent in situ hybridization(FISH). Genetic counseling should be done when they undergo intracytoplasmic sperm injection.

  14. Defective spatial imagery with pure Gerstmann's syndrome.

    PubMed

    Carota, Antonio; Di Pietro, Marie; Ptak, Radek; Poglia, Davide; Schnider, Armin

    2004-01-01

    Gerstmann's syndrome comprises finger agnosia, peripheral agraphia, anarithmetia, and right-left confusion. We here report a single-case study of an 85-year-old ambidextrous man who exhibited pure Gerstmann's syndrome (i.e., without aphasia) 10 weeks after a stroke involving the angular gyrus in the left parietal lobe. We hypothesize that, in this case, the main cognitive denominator of Gerstmann's tetrad was a severe dysfunction in mental rotation and translation. This report provides further evidence for the spatial nature of Gerstmann's syndrome.

  15. Synthesis of highly phase pure BSCCO superconductors

    DOEpatents

    Dorris, Stephen E.; Poeppel, Roger B.; Prorok, Barton C.; Lanagan, Michael T.; Maroni, Victor A.

    1995-01-01

    An article and method of manufacture of (Bi, Pb)-Sr-Ca-Cu-O superconductor. The superconductor is manufactured by preparing a first powdered mixture of bismuth oxide, lead oxide, strontium carbonate, calcium carbonate and copper oxide. A second powdered mixture is then prepared of strontium carbonate, calcium carbonate and copper oxide. The mixtures are calcined separately with the two mixtures then combined. The resulting combined mixture is then subjected to a powder in tube deformation and thermal processing to produce a substantially phase pure (Bi, Pb)-Sr-Ca-Cu-O superconductor.

  16. Synthesis of highly phase pure BSCCO superconductors

    DOEpatents

    Dorris, S.E.; Poeppel, R.B.; Prorok, B.C.; Lanagan, M.T.; Maroni, V.A.

    1995-11-21

    An article and method of manufacture (Bi, Pb)-Sr-Ca-Cu-O superconductor are disclosed. The superconductor is manufactured by preparing a first powdered mixture of bismuth oxide, lead oxide, strontium carbonate, calcium carbonate and copper oxide. A second powdered mixture is then prepared of strontium carbonate, calcium carbonate and copper oxide. The mixtures are calcined separately with the two mixtures then combined. The resulting combined mixture is then subjected to a powder in tube deformation and thermal processing to produce a substantially phase pure (Bi, Pb)-Sr-Ca-Cu-O superconductor. 5 figs.

  17. Pure seminoma: A review and update

    PubMed Central

    2011-01-01

    Pure seminoma is a rare pathology of the young adult, often discovered in the early stages. Its prognosis is generally excellent and many therapeutic options are available, especially in stage I tumors. High cure rates can be achieved in several ways: standard treatment with radiotherapy is challenged by surveillance and chemotherapy. Toxicity issues and the patients' preferences should be considered when management decisions are made. This paper describes firstly the management of primary seminoma and its nodal involvement and, secondly, the various therapeutic options according to stage. PMID:21819630

  18. The role of mnemonic processes in pure-target and pure-foil recognition memory.

    PubMed

    Koop, Gregory J; Criss, Amy H; Malmberg, Kenneth J

    2015-04-01

    Surprisingly, response patterns in a recognition memory test are very similar regardless of whether the test list contains both targets and foils or just one class of items. To better understand these effects, we evaluate performance over the course of testing. Output interference (OI) is the decrease in performance across test trials due to an increase in noise caused by encoded test items. Critically, OI is predicted on pure lists if the mnemonic evidence for each test item is evaluated. In two experiments, participants received accurate feedback, no feedback, or random feedback that was unrelated to the response on each test trial and pure or standard test lists. When no feedback was provided, performance was nearly identical for standard and pure test lists, replicating previous findings. Only in the presence of accurate feedback were participants able to successfully adapt to pure list environments and improve their accuracy. Critically, OI was observed, demonstrating that participants continued to evaluate mnemonic evidence even in pure list conditions. We discuss the implication of these data for models of memory.

  19. Light Higgsinos in pure gravity mediation

    NASA Astrophysics Data System (ADS)

    Evans, Jason L.; Ibe, Masahiro; Olive, Keith A.; Yanagida, Tsutomu T.

    2015-03-01

    Pure gravity mediation, with two free parameters, is a minimalistic approach to supergravity models, yet it is capable of incorporating radiative electroweak symmetry breaking, a Higgs mass in agreement with the experimental measurement, without violating any phenomenological constraints. The model may also contain a viable dark matter candidate in the form of a wino. Here, we extend the minimal model by allowing the μ term to be a free parameter equivalent to allowing the two Higgs soft masses, m1 and m2, to differ from other scalar masses, which are set by the gravitino mass. In particular, we examine the region of parameter space where μ ≪m3 /2, in which case the Higgsino becomes the lightest supersymmetric particle and a dark matter candidate. We also consider a generalization of pure gravity mediation that incorporates a Peccei-Quinn symmetry which determines the μ term dynamically. In this case we show that the dark matter may either be in the form of an axion and/or a neutralino and that the lightest supersymmetric particle may be either a wino, bino, or Higgsino.

  20. Underwater loudness for pure tones: Duration effects

    NASA Astrophysics Data System (ADS)

    Cudahy, Edward A.; Schwaller, Derek; Fothergill, David; Wolgemuth, Keith

    2003-04-01

    The loudness of underwater pure tones was measured by loudness matching for pure tones from 100 to 16,000 Hz. The standard was a one second tone at 1000 Hz. The signal duration was varied from 20 milliseconds to 5 seconds. Subjects were instructed to match the loudness of the comparison tone at one of the test frequencies to the loudness of the standard tone. Loudness was measured at the threshold, the most comfortable loudness, and the maximum tolerable loudness. The intensity of the standard was varied randomly across the test series. The subjects were bareheaded U.S. Navy divers tested at a depth of 3 meters. All subjects had normal in-air hearing. Tones were presented to the right side of the subject from an array of underwater sound projectors. The sound pressure level was calibrated at the location of the subject's head with the subject absent. Loudness increased and threshold decreased as duration increased. The effect was greatest at the lowest and highest frequencies. The shape of the loudness contours across frequency and duration derived from these measurements are different from in-air measurements. [Research supported by ONR.

  1. Dead regions and noisiness of pure tones.

    PubMed

    Huss, Martina; Moore, Brian C J

    2005-10-01

    Some hearing-impaired subjects report pure tones as sounding highly distorted and noise-like. We assessed whether such reports indicate that the tone frequency falls inside a dead region (DR). Nine hearing-impaired and four normally hearing subjects rated pure tones on a scale from 1 to 7, where 1 indicates clear tone and 7 indicates noise. A white noise was presented as a reference for a sound that should be rated as 7. Stimuli covered the whole audible range of frequencies and levels. The noisiness ratings were, on average, higher for hearing-impaired subjects than for normally hearing subjects. For the former, the ratings were not markedly different for tones with frequencies just outside or inside a DR. However, ratings always exceeded 3 for tones falling more than 1.5 octaves inside a DR. The results indicate that judgement of a tone as sounding noise-like does not reliably indicate that the tone frequency falls in a DR. Both normally hearing and hearing-impaired subjects rated 0.125 kHz and 12 kHz tones as somewhat noise-like, independently of the existence of a DR.

  2. Electrokinetics of pure clay minerals revisited

    SciTech Connect

    Sondi, I.; Biscan, J.; Pravdic, V.

    1996-03-25

    Clay minerals have long attracted the attention of colloid scientists. This paper considers, specifically, their important role in the transport of various contaminants from land to sea, e.g., metal ions and organic detrital and man-made material in watercourses. Advance in experimental techniques have enabled precise characterization of clays and then electrokinetic experiments at high electrolyte concentrations, such as in seawater. Three of the most important clay minerals encountered in suspended matter in natural waters, montmorillonite, illite, and chlorite, were prepared in a very pure state. Electrokinetic experiments were done in pure aqueous single and complex electrolyte solutions and in solutions in which natural organic matter was simulated using a humic substance, fulvic acid, of defined provenance and properties, typical of riverine waters. An isoelectric point was found at pH 5.0 {+-} 0.2 for chlorite; none were found for illite and montmorillonite. Only Ca{sup 2+} showed a charging effect on chlorite, indeed a reversal of sign from negative to positive at 1 {times} 10{sup {minus}3} mol dm{sup {minus}3}. Addition of fulvic acid affected only chlorite, illite less, and Na montmorillonite not at all.

  3. Time Evolution of Pure Gravitational Waves

    NASA Astrophysics Data System (ADS)

    Miyama, S. M.

    1981-03-01

    Numerical solutions to the Einstein equations in the case of pure gravitational waves are given. The system is assumed to be axially symmetric and non-rotating. The time symmetric initial data and the conformally flat initial data are obtained by solving the constraint equations at t=0. The time evolution of these initial data depends strongly on the initial amplitude of the gravitational waves. In the case of the low initial amplitude, waves only disperse to null infinity. By comparing the initial gravitational energy with the total energy loss through an r=constant surface, it is concluded that the Newman-Penrose method and the Gibbon-Hawking method are the most desirable for measuring the energy flux of gravitational radiation numerically. In the case that the initial ratio of the spatial extent of the gravitational waves to the Schwarzschild radius (M/2) is smaller than about 300, the waves collapse by themselves, leading to formation of a black hole. The analytic solutions of the linearized Einstein equations for the pure gravitational waves are also shown.

  4. Purely antiferromagnetic magnetoelectric random access memory.

    PubMed

    Kosub, Tobias; Kopte, Martin; Hühne, Ruben; Appel, Patrick; Shields, Brendan; Maletinsky, Patrick; Hübner, René; Liedke, Maciej Oskar; Fassbender, Jürgen; Schmidt, Oliver G; Makarov, Denys

    2017-01-03

    Magnetic random access memory schemes employing magnetoelectric coupling to write binary information promise outstanding energy efficiency. We propose and demonstrate a purely antiferromagnetic magnetoelectric random access memory (AF-MERAM) that offers a remarkable 50-fold reduction of the writing threshold compared with ferromagnet-based counterparts, is robust against magnetic disturbances and exhibits no ferromagnetic hysteresis losses. Using the magnetoelectric antiferromagnet Cr2O3, we demonstrate reliable isothermal switching via gate voltage pulses and all-electric readout at room temperature. As no ferromagnetic component is present in the system, the writing magnetic field does not need to be pulsed for readout, allowing permanent magnets to be used. Based on our prototypes, we construct a comprehensive model of the magnetoelectric selection mechanisms in thin films of magnetoelectric antiferromagnets, revealing misfit induced ferrimagnetism as an important factor. Beyond memory applications, the AF-MERAM concept introduces a general all-electric interface for antiferromagnets and should find wide applicability in antiferromagnetic spintronics.

  5. Purely antiferromagnetic magnetoelectric random access memory

    NASA Astrophysics Data System (ADS)

    Kosub, Tobias; Kopte, Martin; Hühne, Ruben; Appel, Patrick; Shields, Brendan; Maletinsky, Patrick; Hübner, René; Liedke, Maciej Oskar; Fassbender, Jürgen; Schmidt, Oliver G.; Makarov, Denys

    2017-01-01

    Magnetic random access memory schemes employing magnetoelectric coupling to write binary information promise outstanding energy efficiency. We propose and demonstrate a purely antiferromagnetic magnetoelectric random access memory (AF-MERAM) that offers a remarkable 50-fold reduction of the writing threshold compared with ferromagnet-based counterparts, is robust against magnetic disturbances and exhibits no ferromagnetic hysteresis losses. Using the magnetoelectric antiferromagnet Cr2O3, we demonstrate reliable isothermal switching via gate voltage pulses and all-electric readout at room temperature. As no ferromagnetic component is present in the system, the writing magnetic field does not need to be pulsed for readout, allowing permanent magnets to be used. Based on our prototypes, we construct a comprehensive model of the magnetoelectric selection mechanisms in thin films of magnetoelectric antiferromagnets, revealing misfit induced ferrimagnetism as an important factor. Beyond memory applications, the AF-MERAM concept introduces a general all-electric interface for antiferromagnets and should find wide applicability in antiferromagnetic spintronics.

  6. Fock expansion of multimode pure Gaussian states

    SciTech Connect

    Cariolaro, Gianfranco; Pierobon, Gianfranco

    2015-12-15

    The Fock expansion of multimode pure Gaussian states is derived starting from their representation as displaced and squeezed multimode vacuum states. The approach is new and appears to be simpler and more general than previous ones starting from the phase-space representation given by the characteristic or Wigner function. Fock expansion is performed in terms of easily evaluable two-variable Hermite–Kampé de Fériet polynomials. A relatively simple and compact expression for the joint statistical distribution of the photon numbers in the different modes is obtained. In particular, this result enables one to give a simple characterization of separable and entangled states, as shown for two-mode and three-mode Gaussian states.

  7. Synaptic devices based on purely electronic memristors

    SciTech Connect

    Pan, Ruobing; Li, Jun; Zhuge, Fei E-mail: h-cao@nimte.ac.cn; Zhu, Liqiang; Liang, Lingyan; Zhang, Hongliang; Gao, Junhua; Cao, Hongtao E-mail: h-cao@nimte.ac.cn; Fu, Bing; Li, Kang

    2016-01-04

    Memristive devices have been widely employed to emulate biological synaptic behavior. In these cases, the memristive switching generally originates from electrical field induced ion migration or Joule heating induced phase change. In this letter, the Ti/ZnO/Pt structure was found to show memristive switching ascribed to a carrier trapping/detrapping of the trap sites (e.g., oxygen vacancies or zinc interstitials) in ZnO. The carrier trapping/detrapping level can be controllably adjusted by regulating the current compliance level or voltage amplitude. Multi-level conductance states can, therefore, be realized in such memristive device. The spike-timing-dependent plasticity, an important Hebbian learning rule, has been implemented in this type of synaptic device. Compared with filamentary-type memristive devices, purely electronic memristors have potential to reduce their energy consumption and work more stably and reliably, since no structural distortion occurs.

  8. Primate communication in the pure ultrasound

    PubMed Central

    Ramsier, Marissa A.; Cunningham, Andrew J.; Moritz, Gillian L.; Finneran, James J.; Williams, Cathy V.; Ong, Perry S.; Gursky-Doyen, Sharon L.; Dominy, Nathaniel J.

    2012-01-01

    Few mammals—cetaceans, domestic cats and select bats and rodents—can send and receive vocal signals contained within the ultrasonic domain, or pure ultrasound (greater than 20 kHz). Here, we use the auditory brainstem response (ABR) method to demonstrate that a species of nocturnal primate, the Philippine tarsier (Tarsius syrichta), has a high-frequency limit of auditory sensitivity of ca 91 kHz. We also recorded a vocalization with a dominant frequency of 70 kHz. Such values are among the highest recorded for any terrestrial mammal, and a relatively extreme example of ultrasonic communication. For Philippine tarsiers, ultrasonic vocalizations might represent a private channel of communication that subverts detection by predators, prey and competitors, enhances energetic efficiency, or improves detection against low-frequency background noise. PMID:22319094

  9. Allergic contact dermatitis to pure henna.

    PubMed

    Polat, Muhterem; Dikilitaş, Meltem; Oztaş, Pinar; Alli, Nuran

    2009-01-15

    Henna is a naturally occurring brown dye made from the leaves of the tree Lawsonia inermis. The active ingredient of henna is lawsone (2-hydroxy-1, 4-naphthoquinone). It is traditionally used in Islamic and Hindu cultures as a hair coloring and as a dye for decorating the nails or making temporary skin tattoos. Actually, henna has a very low allergic potential. In most cases, allergic reactions not caused by henna, but by the chemical coloring additives that are added to henna mixtures. These additives include agents such as daiminotoluenes and diaminobenzenes. In this article, we report a case of allergic contact dermatitis from pure henna that is also used for the relief of rheumatic pain.

  10. Pure Rotational Spectroscopy of Vinyl Mercaptan

    NASA Astrophysics Data System (ADS)

    Martin-Drumel, Marie-Aline; Zingsheim, Oliver; Thorwirth, Sven; Müller, Holger S. P.; Lewen, Frank; Schlemmer, Stephan

    2014-06-01

    Vinyl mercaptan (ethenethiol, CH_2=CHSH) exists in the gas phase in two distinct rotameric forms, syn (planar) and anti (quasi-planar in the ground vibrational state). The microwave spectra of these two isomers were investigated previously, however not exceeding frequencies of about 65 GHz. In the present investigation, the pure rotational spectra of both species have been investigated at millimeter wavelengths. Vinyl mercaptan was produced in a radiofrequency discharge through a constant flow of ethanedithiol at low pressure. Both syn and anti rotamers were observed and new extensive sets of molecular parameters were obtained. Owing to its close structural relationship to vinyl alcohol and the astronomical abundance of complex sulfur-bearing molecules, vinyl mercaptan is a plausible candidate for future radio astronomical searches. M. Tanimoto et al. J. Mol. Spectrosc. 78, 95--105 & 106--119 (1979)

  11. 77 FR 59979 - Pure Magnesium (Granular) From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-01

    ... COMMISSION Pure Magnesium (Granular) From China Determination On the basis of the record \\1\\ developed in the... antidumping duty order on pure magnesium (granular) from China would be likely to lead to continuation or...), entitled Pure Magnesium (Granular) from China: Investigation No.731-TA- 895 (Second Review). Issued...

  12. ThermoData Engine Database - Pure Compounds and Binary Mixtures

    National Institute of Standards and Technology Data Gateway

    SRD 103b NIST ThermoData Engine Version 6.0 - Pure CompoThermoData Engine Database - Pure Compounds and Binary Mixtures (PC database for purchase)   This database contains property data for more than 21,000 pure compounds, 37,500 binary mixtures, 10,000 ternary mixtures, and 6,000 chemical reactions.

  13. Social cognition in "pure" delusional disorder.

    PubMed

    Bömmer, Isabel; Brüne, Martin

    2006-09-01

    Introduction. Delusional disorders are characterised by monothematic, "encapsulated" and incorrigible false beliefs and misinterpretations of social signals. Due to the rarity of cases with "pure" delusional disorder (DD) in clinical settings most studies of social cognition in delusional patients have focused on patients with paranoid schizophrenia. In the present study we sought to examine emotion recognition, theory of mind abilities, and pragmatic language comprehension in patients with delusional disorder. Methods. Social cognition was assessed in 21 patients recruited over a 3-year period who were diagnosed with delusional disorder, paranoid, erotomanic, or jealous type. In addition to an emotion recognition and theory of mind test battery, we included a novel German Proverb Test, which has been found indicative of subtle theory of mind deficits in schizophrenic patients. Executive functioning was assessed using the Wisconsin Card Sorting Test (WCST). Psychopathology was measured using the Positive and Negative Symptoms Scale (PANSS). Patients' task performance was compared to a group of 22 healthy control persons paralleled for verbal intelligence, education, and age. Results. Patients with DD made significantly more perseverative errors in the WCST, they performed more poorly on the theory of mind tasks and the proverb test, but were unimpaired in basic emotion recognition abilities relative to controls. When executive functioning was co-varied out, the group differences in theory of mind disappeared, whereas the greater propensity of patients with DD to interpret proverbs literally remained significant. Conclusions. In "pure" DD the basic social cognitive abilities appear to be preserved. Difficulties in metaphorical speech comprehension and executive functioning could, however, indicate more subtle social cognitive deficits in these patients.

  14. Hubble Infrared Pure Parallel Imaging Extragalactic Survey {HIPPIES}

    NASA Astrophysics Data System (ADS)

    Yan, Haojing

    2010-09-01

    WFC3 has demonstrated its unprecedented power in probing the early universe. Here we propose to continue our pure parallel program with this instrument to search for LBGs at z 6-8. Our program, dubbed as the Hubble Infrared Pure Parallel Imaging Extragalactic Survey {"HIPPIES"}, will carry on the HST pure parallel legacy in the new decade. We request 205 orbits in Cycle-18, which will spread over 50 high Galactic latitude visits {|b|>20deg} that last for 3 orbits and longer, resulting a total survey area of 230 square arcmin. Combining the WFC3 pure parallel observations in Cycle-17, HIPPIES will complement other existing and forthcoming WFC3 surveys, and will make unique contributions to the study in the new redshift frontier because of the randomness of the survey fields. To make full use of the parallel opportunities, HIPPIES will also take ACS parallels to study LBGs at z 5-6. Being a pure parallel program, HIPPIES will only make very limited demand on the scarce HST resources, but will have potentially large scientific returns. As in previous cycle, we waive all proprietary data rights, and will make the enhanced data products public in a timely manner. {1} The WFC3 part of HIPPIES aims at the most luminous LBG population at z 8 and z 7. As its survey fields are random and completely uncorrelated, the number counts of the bright LBGs from HIPPIES will be least affected by the "cosmic variance", and hence we will be able to obtain the best constraint on the bright-end of the LBG luminosity function at z 8 and 7. Comparing the result from HIPPIES to the hydrodynamic simulations will test the input physics and provide insight into the nature of the early galaxies. {2} The z 7-8 candidates from HIPPIES, most of which will be the brightest ones that any surveys would be able to find, will have the best chance to be spectroscopically confirmed at the current 8-10m telescopes. {3} The ACS part of HIPPIES will produce a significant number of candidate LBGs at z 5 and

  15. Chondrule Destruction in Nebular Shocks

    NASA Astrophysics Data System (ADS)

    Jacquet, Emmanuel; Thompson, Christopher

    2014-12-01

    Chondrules are millimeter-sized silicate spherules ubiquitous in primitive meteorites, but whose origin remains mysterious. One of the main proposed mechanisms for producing them is melting of solids in shock waves in the gaseous protoplanetary disk. However, evidence is mounting that chondrule-forming regions were enriched in solids well above solar abundances. Given the high velocities involved in shock models, destructive collisions would be expected between differently sized grains after passage of the shock front as a result of differential drag. We investigate the probability and outcome of collisions of particles behind a one-dimensional shock using analytic methods as well as a full integration of the coupled mass, momentum, energy, and radiation equations. Destruction of protochondrules seems unavoidable for solid/gas ratios epsilon >~ 0.1, and possibly even for solar abundances because of "sandblasting" by finer dust. A flow with epsilon >~ 10 requires much smaller shock velocities (~2 versus 8 km s-1) in order to achieve chondrule-melting temperatures, and radiation trapping allows slow cooling of the shocked fragments. Initial destruction would still be extensive; although re-assembly of millimeter-sized particles would naturally occur by grain sticking afterward, the compositional heterogeneity of chondrules may be difficult to reproduce. We finally note that solids passing through small-scale bow shocks around few kilometer-sized planetesimals might experience partial melting and yet escape fragmentation.

  16. Chondrule destruction in nebular shocks

    SciTech Connect

    Jacquet, Emmanuel; Thompson, Christopher

    2014-12-10

    Chondrules are millimeter-sized silicate spherules ubiquitous in primitive meteorites, but whose origin remains mysterious. One of the main proposed mechanisms for producing them is melting of solids in shock waves in the gaseous protoplanetary disk. However, evidence is mounting that chondrule-forming regions were enriched in solids well above solar abundances. Given the high velocities involved in shock models, destructive collisions would be expected between differently sized grains after passage of the shock front as a result of differential drag. We investigate the probability and outcome of collisions of particles behind a one-dimensional shock using analytic methods as well as a full integration of the coupled mass, momentum, energy, and radiation equations. Destruction of protochondrules seems unavoidable for solid/gas ratios ε ≳ 0.1, and possibly even for solar abundances because of 'sandblasting' by finer dust. A flow with ε ≳ 10 requires much smaller shock velocities (∼2 versus 8 km s{sup –1}) in order to achieve chondrule-melting temperatures, and radiation trapping allows slow cooling of the shocked fragments. Initial destruction would still be extensive; although re-assembly of millimeter-sized particles would naturally occur by grain sticking afterward, the compositional heterogeneity of chondrules may be difficult to reproduce. We finally note that solids passing through small-scale bow shocks around few kilometer-sized planetesimals might experience partial melting and yet escape fragmentation.

  17. Power plant of high safety for underground nuclear power station

    SciTech Connect

    Dolgov, V.N.

    1993-12-31

    An ecologically pure, reliable, and economic nuclear power station is based on the use of nuclear power plants with the liquid-metal coolant. This plant with the inherent safety is protected from external influences due to the underground accommodations in geologically stable formations such as granites, cambrian clays, and salt deposits. The design features of this underground plant are described.

  18. Pure Material Vapor Source by Induction Heating Evaporator for an Electron Cyclotron Resonance Ion Source

    SciTech Connect

    Matsui, Y.; Watanabe, T.; Satani, T.; Sato, F.; Kato, Y.; Iida, T.; Muramatsu, M.; Kitagawa, A.; Tanaka, K.; Yoshida, Y.

    2008-11-03

    Multiply charged iron ions are produced from solid pure material in an electron cyclotron resonance (ECR) ion source. We develop an evaporator by using induction heating with the induction coil which is made from bare molybdenum wire and surrounding the pure iron rod. We optimize the shape of induction heating coil and operation of rf power supply. We conduct experiment to investigate reproducibility and stability in the operation and heating efficiency. Induction heating evaporator produces pure material vapor, because materials directly heated by eddy currents have non-contact with insulated materials which are impurity gas sources. The power and the frequency of the induction currents range from 100 to 900 W and from 48 to 23 kHz, respectively. The working pressure is about 10{sup -4} to 10{sup -3} Pa. We measure temperature of iron rod and film deposition rate by depositing iron vapor to crystal oscillator. We confirm stability and reproducibility of evaporator enough to conduct experiment in ECR ion source. We can obtain required temperature of iron under maximum power of power supply. We are aiming the evaporator higher melting point material than iron.

  19. Solar-Powered Water Distillation

    NASA Technical Reports Server (NTRS)

    Menninger, F. J.; Elder, R. J.

    1985-01-01

    Solar-powered still produces pure water at rate of 6,000 gallons per year. Still fully automatic and gravity-fed. Only outside electric power is timer clock and solenoid-operated valve. Still saves $5,000 yearly in energy costs and pays for itself in 3 1/2 years.

  20. Accelerating degradation rate of pure iron by zinc ion implantation.

    PubMed

    Huang, Tao; Zheng, Yufeng; Han, Yong

    2016-12-01

    Pure iron has been considered as a promising candidate for biodegradable implant applications. However, a faster degradation rate of pure iron is needed to meet the clinical requirement. In this work, metal vapor vacuum arc technology was adopted to implant zinc ions into the surface of pure iron. Results showed that the implantation depth of zinc ions was about 60 nm. The degradation rate of pure iron was found to be accelerated after zinc ion implantation. The cytotoxicity tests revealed that the implanted zinc ions brought a slight increase on cytotoxicity of the tested cells. In terms of hemocompatibility, the hemolysis of zinc ion implanted pure iron was lower than 2%. However, zinc ions might induce more adhered and activated platelets on the surface of pure iron. Overall, zinc ion implantation can be a feasible way to accelerate the degradation rate of pure iron for biodegradable applications.

  1. Stable pure state quantum tomography from five orthonormal bases

    NASA Astrophysics Data System (ADS)

    Carmeli, Claudio; Heinosaari, Teiko; Kech, Michael; Schultz, Jussi; Toigo, Alessandro

    2016-08-01

    For any finite-dimensional Hilbert space, we construct explicitly five orthonormal bases such that the corresponding measurements allow for efficient tomography of an arbitrary pure quantum state. This means that such measurements can be used to distinguish an arbitrary pure state from any other state, pure or mixed, and the pure state can be reconstructed from the outcome distribution in a feasible way. The set of measurements we construct is independent of the unknown state, and therefore our results provide a fixed scheme for pure state tomography, as opposed to the adaptive (state-dependent) scheme proposed by Goyeneche et al. (Phys. Rev. Lett., 115 (2015) 090401). We show that our scheme is robust with respect to noise, in the sense that any measurement scheme which approximates these measurements well enough is equally suitable for pure state tomography. Finally, we present two convex programs which can be used to reconstruct the unknown pure state from the measurement outcome distributions.

  2. Accelerating degradation rate of pure iron by zinc ion implantation

    PubMed Central

    Huang, Tao; Zheng, Yufeng; Han, Yong

    2016-01-01

    Pure iron has been considered as a promising candidate for biodegradable implant applications. However, a faster degradation rate of pure iron is needed to meet the clinical requirement. In this work, metal vapor vacuum arc technology was adopted to implant zinc ions into the surface of pure iron. Results showed that the implantation depth of zinc ions was about 60 nm. The degradation rate of pure iron was found to be accelerated after zinc ion implantation. The cytotoxicity tests revealed that the implanted zinc ions brought a slight increase on cytotoxicity of the tested cells. In terms of hemocompatibility, the hemolysis of zinc ion implanted pure iron was lower than 2%. However, zinc ions might induce more adhered and activated platelets on the surface of pure iron. Overall, zinc ion implantation can be a feasible way to accelerate the degradation rate of pure iron for biodegradable applications. PMID:27482462

  3. AgraPure Mississippi Biomass Project

    SciTech Connect

    Blackwell,D.A; Broadhead, L.W.; Harrell, W.J.

    2006-03-31

    The AgraPure Mississippi Biomass project was a congressionally directed project, initiated to study the utilization of Mississippi agricultural byproducts and waste products in the production of bio-energy and to determine the feasibility of commercialization of these agricultural byproducts and waste products as feedstocks in the production of energy. The final products from this project were two business plans; one for a Thermal plant, and one for a Biodiesel/Ethanol plant. Agricultural waste fired steam and electrical generating plants and biodiesel plants were deemed the best prospects for developing commercially viable industries. Additionally, oil extraction methods were studied, both traditional and two novel techniques, and incorporated into the development plans. Mississippi produced crop and animal waste biomasses were analyzed for use as raw materials for both industries. The relevant factors, availability, costs, transportation, storage, location, and energetic value criteria were considered. Since feedstock accounts for more than 70 percent of the total cost of producing biodiesel, any local advantages are considered extremely important in developing this particular industry. The same factors must be evaluated in assessing the prospects of commercial operation of a steam and electrical generation plant. Additionally, the access to the markets for electricity is more limited, regulated and tightly controlled than the liquid fuel markets. Domestically produced biofuels, both biodiesel and ethanol, are gaining more attention and popularity with the consuming public as prices rise and supplies of foreign crude become less secure. Biodiesel requires no major modifications to existing diesel engines or supply chain and offers significant environmental benefits. Currently the biodiesel industry requires Federal and State incentives to allow the industry to develop and become self-sustaining. Mississippi has available the necessary feedstocks and is

  4. Power Spectral Density and Hilbert Transform

    DTIC Science & Technology

    2016-12-01

    there is 1.3 W of power. How much bandwidth does a pure sine wave require? The bandwidth of an ideal sine wave is 0 Hz. How do you represent a 1-W... sine wave source (power concentrated in a single frequency) on a power spectral density graph (power per frequency, watts per hertz)? The Dirac delta...represent the power contained in a sine wave (zero bandwidth) on a power spectral density graph. Fig. 1 Dirac delta function () =

  5. Effect of laser soldering irradiation on covalent bonds of pure collagen.

    PubMed

    Constantinescu, Mihai A; Alfieri, Alex; Mihalache, George; Stuker, Florian; Ducray, Angélique; Seiler, Rolf W; Frenz, Martin; Reinert, Michael

    2007-03-01

    Laser tissue welding and soldering is being increasingly used in the clinical setting for defined surgical procedures. The exact induced changes responsible for tensile strength are not yet fully investigated. To further improve the strength of the bonding, a better understanding of the laser impact at the subcellular level is necessary. The goal of this study was to analyze whether the effect of laser irradiation on covalent bonding in pure collagen using irradiances typically applied for tissue soldering. Pure rabbit and equine type I collagen were subjected to laser irradiation. In the first part of the study, rabbit and equine collagen were compared using identical laser and irradiation settings. In the second part of the study, equine collagen was irradiated at increasing laser powers. Changes in covalent bonding were studied indirectly using the sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) technique. Tensile strengths of soldered membranes were measured with a calibrated tensile force gauge. In the first experiment, no differences between the species-specific collagen bands were noted, and no changes in banding were found on SDS-PAGE after laser irradiation. In the second experiment, increasing laser irradiation power showed no effect on collagen banding in SDS-PAGE. Finally, the laser tissue soldering of pure collagen membranes showed virtually no determinable tensile strength. Laser irradiation of pure collagen at typical power settings and exposure times generally used in laser tissue soldering does not induce covalent bonding between collagen molecules. This is true for both rabbit and equine collagen proveniences. Furthermore, soldering of pure collagen membranes without additional cellular components does not achieve the typical tensile strength reported in native, cell-rich tissues. This study is a first step in a better understanding of laser impact at the molecular level and might prove useful in engineering of combined

  6. Pure Culture Fermentation of Brined Cucumbers1

    PubMed Central

    Etchells, J. L.; Costilow, R. N.; Anderson, T. E.; Bell, T. A.

    1964-01-01

    The relative abilities of Pediococcus cerevisiae, Lactobacillus plantarum, L. brevis, and several other species of lactic acid bacteria to grow and produce acid in brined cucumbers were evaluated in pure culture fermentations. Such fermentations were made possibly by the use of two techniques, gamma radiation (0.83 to 1.00 Mrad) and hot-water blanching (66 to 80 C for 5 min), designed first to rid the cucumbers of naturally occurring, interfering, and competitive microbial groups prior to brining, followed by inoculation with the desired lactic acid bacteria. Of the nine species tested, strains of the three common to cucumber fermentations, P. cerevisiae, L. plantarum, and L. brevis, grew to the highest populations, and produced the highest levels of brine acidity and the lowest pH values in fermentations at 5.4 to 5.6% NaCl by weight; also, their sequence of active development in fermentations, with the use of a three-species mixture for inoculation, was in the species order just named. This sequence of occurrence was similar to that estimated by others for natural fermentations. The rates of growth and acid production in fermentations with a mixture of P. cerevisiae, L. plantarum, and L. brevis increased as the incubation temperature was increased from 21 to 27 to 32 C; however, the maximal populations and acidities attained were essentially the same for fermentations at each temperature. Further, these same three species were found to be the most salt tolerant of those tested; their upper limit for appreciable growth and measurable acid production was about 8% salt, whereas thermophilic species such as L. thermophilus, L. lactis, L. helveticus, L. fermenti, and L. delbrueckii exhibited a much lower salt tolerance, ranging from about 2.5 to 4.0%. However, certain strains of L. delbrueckii grew very rapidly in cucumbers brined at 2.5 to 3.0% salt, and produced sufficient acid in about 30 hr at 48 C to reduce the brine pH from above 7.0 to below 4.0. An inexpensive

  7. Electron Acoustic Waves in Pure Ion Plasmas

    NASA Astrophysics Data System (ADS)

    Anderegg, Francois

    2008-11-01

    Electron Acoustic Waves (EAWs) are the low frequency branch of electrostatic plasma waves; these waves exist in neutralized plasmas, pure electrons, and pure ion plasmas. The EAWs typically have a phase velocity Vphase / Vth ˜1.4, quite low compared to typical plasma waves. Linear Landau damping would suggest that such slow phase velocity waves are strongly damped; but at finite wave amplitudes, trapping of particles at the phase velocity effectively flattens the distribution function, resulting in a ``BGK-like'' state with weak damping. Our experiments on standing mz= 1, mθ= 0 waves show that the small-amplitude dispersion relation for both fast Trivelpiece-Gould (TG) and slow (EAW) plasma modes is in close agreement with the ``thumb-shaped'' dispersion relation predicted by kinetic theory neglecting damping. However, the surprise here is that a moderate amplitude ``off-resonant'' drive readily modifies the velocity distribution so as to make the plasma mode resonant with the drive frequency. We have observed the plasma adjusting its velocity distribution so as to become resonant with a 100 cycle drive ranging from 10 kHz to 30 kHz. With a chirped frequency drive, the particle velocity distribution suffers extreme distortion, and the resulting plasma wave is almost undamped with γ/ φ˜10-5. Laser-Induced-Fluorescence measurements of the wave-coherent particle distribution f (vz, t), clearly show particle trapping in the EAW, with trapping widths as expected from theory considering two non-interacting traveling waves forming the standing wave. The coherent f (vz, t ) measurement also shows that particles slower than the wave phase velocity vph oscillate in phase with the wave, contrasting with the 180^o out-of-phase response of the particles moving faster than vph. The differing response of the fast and slow particles results in a small net fluid velocity, because the electrostatic restoring force is almost totally balanced by the kinetic pressure, consistent

  8. Pure Culture Fermentation of Brined Cucumbers.

    PubMed

    Etchells, J L; Costilow, R N; Anderson, T E; Bell, T A

    1964-11-01

    The relative abilities of Pediococcus cerevisiae, Lactobacillus plantarum, L. brevis, and several other species of lactic acid bacteria to grow and produce acid in brined cucumbers were evaluated in pure culture fermentations. Such fermentations were made possibly by the use of two techniques, gamma radiation (0.83 to 1.00 Mrad) and hot-water blanching (66 to 80 C for 5 min), designed first to rid the cucumbers of naturally occurring, interfering, and competitive microbial groups prior to brining, followed by inoculation with the desired lactic acid bacteria. Of the nine species tested, strains of the three common to cucumber fermentations, P. cerevisiae, L. plantarum, and L. brevis, grew to the highest populations, and produced the highest levels of brine acidity and the lowest pH values in fermentations at 5.4 to 5.6% NaCl by weight; also, their sequence of active development in fermentations, with the use of a three-species mixture for inoculation, was in the species order just named. This sequence of occurrence was similar to that estimated by others for natural fermentations. The rates of growth and acid production in fermentations with a mixture of P. cerevisiae, L. plantarum, and L. brevis increased as the incubation temperature was increased from 21 to 27 to 32 C; however, the maximal populations and acidities attained were essentially the same for fermentations at each temperature. Further, these same three species were found to be the most salt tolerant of those tested; their upper limit for appreciable growth and measurable acid production was about 8% salt, whereas thermophilic species such as L. thermophilus, L. lactis, L. helveticus, L. fermenti, and L. delbrueckii exhibited a much lower salt tolerance, ranging from about 2.5 to 4.0%. However, certain strains of L. delbrueckii grew very rapidly in cucumbers brined at 2.5 to 3.0% salt, and produced sufficient acid in about 30 hr at 48 C to reduce the brine pH from above 7.0 to below 4.0. An inexpensive

  9. CO-SPATIAL LONG-SLIT UV/OPTICAL SPECTRA OF TEN GALACTIC PLANETARY NEBULAE WITH HST/STIS. II. NEBULAR MODELS, CENTRAL STAR PROPERTIES, AND He+CNO SYNTHESIS

    SciTech Connect

    Henry, R. B. C.; Miller, T. R.; Balick, B.; Dufour, R. J.; Kwitter, K. B.; Shaw, R. A.; Buell, J. F.; Corradi, R. L. M.

    2015-11-10

    The goal of the present study is twofold. First, we employ new HST/STIS spectra and photoionization modeling techniques to determine the progenitor masses of eight planetary nebulae (IC 2165, IC 3568, NGC 2440, NGC 3242, NGC 5315, NGC 5882, NGC 7662, and PB 6). Second, for the first time we are able to compare each object’s observed nebular abundances of helium, carbon, and nitrogen with abundance predictions of these same elements by a stellar model that is consistent with each object’s progenitor mass. Important results include the following: (1) the mass range of our objects’ central stars matches well with the mass distribution of other central stars of planetary nebulae and white dwarfs; (2) He/H is above solar in all of our objects, in most cases likely due to the predicted effects of first dredge-up; (3) most of our objects show negligible C enrichment, probably because their low masses preclude third dredge-up; (4) C/O versus O/H for our objects appears to be inversely correlated, which is perhaps consistent with the conclusion of theorists that the extent of atmospheric carbon enrichment from first dredge-up is sensitive to a parameter whose value increases as metallicity declines; (5) stellar model predictions of nebular C and N enrichment are consistent with observed abundances for progenitor star masses ≤1.5 M{sub ⊙}. Finally, we present the first published photoionization models of NGC 5315 and NGC 5882.

  10. Application of cellulase and hemicellulase to pure xylan, pure cellulose, and switchgrass solids from leading pretreatments.

    PubMed

    Shi, Jian; Ebrik, Mirvat A; Yang, Bin; Garlock, Rebecca J; Balan, Venkatesh; Dale, Bruce E; Pallapolu, V Ramesh; Lee, Y Y; Kim, Youngmi; Mosier, Nathan S; Ladisch, Michael R; Holtzapple, Mark T; Falls, Matthew; Sierra-Ramirez, Rocio; Donohoe, Bryon S; Vinzant, Todd B; Elander, Richard T; Hames, Bonnie; Thomas, Steve; Warner, Ryan E; Wyman, Charles E

    2011-12-01

    Accellerase 1000 cellulase, Spezyme CP cellulase, β-glucosidase, Multifect xylanase, and beta-xylosidase were evaluated for hydrolysis of pure cellulose, pure xylan, and switchgrass solids from leading pretreatments of dilute sulfuric acid, sulfur dioxide, liquid hot water, lime, soaking in aqueous ammonia, and ammonia fiber expansion. Distinctive sugar release patterns were observed from Avicel, phosphoric acid swollen cellulose (PASC), xylan, and pretreated switchgrass solids, with accumulation of significant amounts of xylooligomers during xylan hydrolysis. The strong inhibition of cellulose hydrolysis by xylooligomers could be partially attributed to the negative impact of xylooligomers on cellulase adsorption. The digestibility of pretreated switchgrass varied with pretreatment but could not be consistently correlated to xylan, lignin, or acetyl removal. Initial hydrolysis rates did correlate well with cellulase adsorption capacities for all pretreatments except lime, but more investigation is needed to relate this behavior to physical and compositional properties of pretreated switchgrass. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Reexamination of pure qubit work extraction.

    PubMed

    Frenzel, Max F; Jennings, David; Rudolph, Terry

    2014-11-01

    Many work extraction or information erasure processes in the literature involve the raising and lowering of energy levels via external fields. But even if the actual system is treated quantum mechanically, the field is assumed to be classical and of infinite strength, hence not developing any correlations with the system or experiencing back-actions. We extend these considerations to a fully quantum mechanical treatment by studying a spin-1/2 particle coupled to a finite-sized directional quantum reference frame, a spin-l system, which models an external field. With this concrete model together with a bosonic thermal bath, we analyze the back-action a finite-size field suffers during a quantum-mechanical work extraction process and the effect this has on the extractable work and highlight a range of assumptions commonly made when considering such processes. The well-known semiclassical treatment of work extraction from a pure qubit predicts a maximum extractable work W=kTlog2 for a quasistatic process, which holds as a strict upper bound in the fully quantum mechanical case and is attained only in the classical limit. We also address the problem of emergent local time dependence in a joint system with a globally fixed Hamiltonian.

  12. The Pure Rotational Spectrum of KO

    NASA Astrophysics Data System (ADS)

    Burton, Mark; Russ, Benjamin; Sheridan, Phillip M.; Bucchino, Matthew; Ziurys, Lucy M.

    2017-06-01

    The pure rotational spectrum of potassium monoxide (KO) has been recorded using millimeter-wave direct absorption spectroscopy. KO was synthesized by the reaction of potassium vapor, produced in a Broida-type oven, with nitrous oxide. No DC discharge was necessary. Eleven rotational transitions belonging to the ^{2}Π_{3/2} spin-orbit component have been measured and have been fit successfully to a case (c) Hamiltonian. Rotational and lambda-doubling constants for this spin-orbit component have been determined. It has been suggested that the ground electronic state of KO is either ^{2}Π (as for LiO and NaO) or ^{2}Σ (as for RbO and CsO), both of which lie close in energy. Recent computational studies favor a ^{2}Σ ground state. Further measurements of the rotational transitions of the ^{2}Π_{1/2} spin-orbit component and the ^{2}Σ state are currently in progress, as well as the potassium hyperfine structure.

  13. Calibration of sound velocimeter in pure water

    NASA Astrophysics Data System (ADS)

    Li, Zhiwei; Zhang, Baofeng; Li, Tao; Zhu, Junchao; Xie, Ziming

    2016-01-01

    Accurate measurement of sound speed is important to calibrate a sound velocity profiler which provides real-time sound velocity to the sonar equipment in oceanographic survey. The sound velocity profiler calculates the sound speed by measuring the time-of-flight of a 1 MHz single acoustic pulse to travel over about 300 mm path. A standard sound velocimeter instrument was invited to calibrate the sound velocity profiler in pure water at temperatures of 278,283, 288, 293, 298, 303 and 308K in a thermostatic vessel at one atmosphere. The sound velocity profiler was deployed in the thermostatic vessel alongside the standard sound velocimeter instrument and two platinum resistance thermometers (PRT) which were calibrated to 0.002k by comparison with a standard PRT. Time of flight circuit board was used to measure the time-of-flight to 22 picosecond precision. The sound speed which was measured by the sound velocity profiler was compared to the standard sound speed calculated by UNESCO to give the laboratory calibration coefficients and was demonstrated agreement with CTD-derived sound speed using Del Grosso's seawater equation after removing a bias.

  14. Twofold symmetries of the pure gravity action

    NASA Astrophysics Data System (ADS)

    Cheung, Clifford; Remmen, Grant N.

    2017-01-01

    We recast the action of pure gravity into a form that is invariant under a twofold Lorentz symmetry. To derive this representation, we construct a general parameterization of all theories equivalent to the Einstein-Hilbert action up to a local field redefinition and gauge fixing. We then exploit this freedom to eliminate all interactions except those exhibiting two sets of independently contracted Lorentz indices. The resulting action is local, remarkably simple, and naturally expressed in a field basis analogous to the exponential parameterization of the nonlinear sigma model. The space of twofold Lorentz invariant field redefinitions then generates an infinite class of equivalent representations. By construction, all off-shell Feynman diagrams are twofold Lorentz invariant while all on-shell tree amplitudes are automatically twofold gauge invariant. We extend our results to curved spacetime and calculate the analogue of the Einstein equations. While these twofold invariances are hidden in the canonical approach of graviton perturbation theory, they are naturally expected given the double copy relations for scattering amplitudes in gauge theory and gravity.

  15. Ponytail headache: a pure extracranial headache.

    PubMed

    Blau, J N

    2004-05-01

    Fifty of 93 females experienced headache from wearing a ponytail. Pain was experienced only at the site of the hair tie in 10 subjects, extending in others, forwards to the vertex (n = 5) or forehead (n = 7), laterally to the parietal region (n = 8) or temples (n = 3), downwards to the neck (n = 5), or to other areas (n = 12). Loosening the hair relieved pain immediately in 4 subjects, within half an hour in 32, and within an hour in 5 subjects; the remaining 9 subjects were uncertain of pain duration. This headache was preventable by wearing the ponytail more loosely tied. Ponytail headache, well known to females, is not described in the medical literature because the remedy is obvious, therefore those affected do not seek medical advice. This seemingly common headache provides an example of a pure extracranial headache arising from pericranial muscle fascia and tendon traction. Males almost certainly have similar experiences, but were not questioned in this study. Distinguishing intracranial from extracranial headache is essential in diagnosis and treatment. Further research on ponytail and other extracranial headaches could shed light on the mechanism of tension-type headache.

  16. Reduction of hydrogen content in pure Ti

    NASA Astrophysics Data System (ADS)

    Ogiwara, N.; Suganuma, K.; Hikichi, Y.; Kamiya, J.; Kinsho, M.; Sukenobu, S.

    2008-03-01

    Pure Ti is adopted as a material for ducts and bellows at the proton accelerator 3 GeV-RCS in J-PARC project, because of its small residual radioactivity. In the particle accelerator, the H2 outgassing due to ion impact is often the dominant source of gas release. As the reduction of hydrogen content will probably suppress ion induced desorption, we attempted to reduce the hydrogen content in the Ti by in-situ vacuum baking. First, thermal desorption behavior and the change in hydrogen content after the heat treatment were investigated. Vacuum firing at temperatures higher than 550°C was effective in reducing the hydrogen content in the Ti. At the same time, the mechanical properties were monitored because grain growth leads to decrease in mechanical strength. Even after treatment at 750°C for 12 hr, the decreases in tensile and yield strength were so small (~10%) that we have no anxiety about the reduction of mechanical strength. Based upon the results of this study, vacuum firing has been applied to reduce the hydrogen content in the Ti bellows and ducts of the RCS machine.

  17. Memory for pure tone sequences without contour.

    PubMed

    Lefebvre, Christine; Jolicœur, Pierre

    2016-06-01

    We presented pure tones interspersed with white noise sounds to disrupt contour perception in an acoustic short-term memory (ASTM) experiment during which we recorded the electroencephalogram. The memory set consisted of seven stimuli, 0, 1, 2, 3, or 4 of which were to-be-remembered tones. We estimated each participant׳s capacity, K, for each set size and measured the amplitude of the SAN (sustained anterior negativity, an ERP related to acoustic short-term memory). We correlated their K slopes with their SAN amplitude slopes as a function of set size, and found a significant link between performance and the SAN: a larger increase in SAN amplitude was linked with a larger number of stimuli maintained in ASTM. The SAN decreased in amplitude in the later portion of the silent retention interval, but the correlation between the SAN and capacity remained strong. These results show the SAN is not an index of contour but rather an index of the maintenance of individual objects in STM. This article is part of a Special Issue entitled SI: Auditory working memory. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Purely antiferromagnetic magnetoelectric random access memory

    PubMed Central

    Kosub, Tobias; Kopte, Martin; Hühne, Ruben; Appel, Patrick; Shields, Brendan; Maletinsky, Patrick; Hübner, René; Liedke, Maciej Oskar; Fassbender, Jürgen; Schmidt, Oliver G.; Makarov, Denys

    2017-01-01

    Magnetic random access memory schemes employing magnetoelectric coupling to write binary information promise outstanding energy efficiency. We propose and demonstrate a purely antiferromagnetic magnetoelectric random access memory (AF-MERAM) that offers a remarkable 50-fold reduction of the writing threshold compared with ferromagnet-based counterparts, is robust against magnetic disturbances and exhibits no ferromagnetic hysteresis losses. Using the magnetoelectric antiferromagnet Cr2O3, we demonstrate reliable isothermal switching via gate voltage pulses and all-electric readout at room temperature. As no ferromagnetic component is present in the system, the writing magnetic field does not need to be pulsed for readout, allowing permanent magnets to be used. Based on our prototypes, we construct a comprehensive model of the magnetoelectric selection mechanisms in thin films of magnetoelectric antiferromagnets, revealing misfit induced ferrimagnetism as an important factor. Beyond memory applications, the AF-MERAM concept introduces a general all-electric interface for antiferromagnets and should find wide applicability in antiferromagnetic spintronics. PMID:28045029

  19. Electron Acoustic Waves in Pure Ion Plasmas

    NASA Astrophysics Data System (ADS)

    Anderegg, F.; Affolter, M.; Driscoll, C. F.; O'Neil, T. M.; Valentini, F.

    2012-10-01

    Electron Acoustic Waves (EAWs) are the low-frequency branch of near-linear Langmuir (plasma) waves: the frequency is such that the complex dielectric function (Dr, Di) has Dr= 0; and ``flattening'' of f(v) near the wave phase velocity vph gives Di=0 and eliminates Landau damping. Here, we observe standing axisymmetric EAWs in a pure ion column.footnotetextF. Anderegg, et al., Phys. Rev. Lett. 102, 095001 (2009). At low excitation amplitudes, the EAWs have vph˜1.4 v, in close agreement with near-linear theory. At moderate excitation strengths, EAW waves are observed over a range of frequencies, with 1.3 v < vph< 2.1 v. Here, the final wave frequency may differ from the excitation frequency since the excitation modifies f (v); and recent theory analyzes frequency shifts from ``corners'' of a plateau at vph.footnotetextF. Valentini et al., arXiv:1206.3500v1. Large amplitude EAWs have strong phase-locked harmonic content, and experiments will be compared to same-geometry simulations, and to simulations of KEENfootnotetextB. Afeyan et al., Proc. Inertial Fusion Sci. and Applications 2003, A.N.S. Monterey (2004), p. 213. waves in HEDLP geometries.

  20. Pure inorganic separator for lithium ion batteries.

    PubMed

    He, Meinan; Zhang, Xinjie; Jiang, Kuiyang; Wang, Joe; Wang, Yan

    2015-01-14

    Battery safety is critical for many applications including portable electronics, hybrid and electric vehicles, and grid storage. For lithium ion batteries, the conventional polymer based separator is unstable at 120 °C and above. In this research, we have developed a pure aluminum oxide nanowire based separator; this separator does not contain any polymer additives or binders; additionally, it is a bendable ceramic. The physical and electrochemical properties of the separator are investigated. The separator has a pore size of about 100 nm, and it shows excellent electrochemical properties under both room and high temperatures. At room temperature, the ceramic separator shows a higher rate capability compared to the conventional Celgard 2500 separator and life cycle performance does not show any degradation. At 120 °C, the cell with the ceramic separator showed a much better cycle performance than the conventional Celgard 2500 separator. Therefore, we believe that this research is really an exciting scientific breakthrough for ceramic separators and lithium ion batteries and could be potentially used in the next generation lithium ion batteries requiring high safety and reliability.

  1. Triplet pairing in pure neutron matter

    NASA Astrophysics Data System (ADS)

    Srinivas, Sarath; Ramanan, S.

    2016-12-01

    We study the zero-temperature BCS gaps for the triplet channel in pure neutron matter using similarity renormalization group (SRG) evolved interactions. We use the dependence of the results on the SRG resolution scale as a tool to analyze medium and many-body corrections. In particular, we study the effects of including the three-body interactions at leading order, which appear at next-to-next-to leading order (N2LO) in the chiral effective field theory (EFT), as well as that of the first-order self-energy corrections on the zero-temperature gap. In addition we also extract the transition temperature as a function of densities and verify the BCS scaling of the zero-temperature gaps to the transition temperature. We observe that the self-energy effects are very crucial in order to reduce the SRG resolution scale dependence of the results, while the three-body effects at the leading order do not change the two-body resolution scale dependence. On the other hand, the results depend strongly on the three-body cutoff, emphasizing the importance of the missing higher-order three-body effects. We also observe that self-energy effects reduce the overall gap as well as shift the gap closure to lower densities.

  2. Triplet pairing in pure neutron matter

    NASA Astrophysics Data System (ADS)

    Srinivas, Sarath; Ramanan, Sunethra

    2016-09-01

    We study the zero temperature BCS gaps for the triplet channel in pure neutron matter using Similarity Renormalization Group (SRG) evolved interactions. We use the dependence of the results on the SRG resolution scale, as a tool to analyze medium and many-body corrections. In particular, we study the effects of including the three-body interactions at leading order, which appear at N2LO in the Chiral EFT, as well as that of the first-order self-energy corrections on the zero temperature gap. In addition we also extract the transition temperature as a function of densities and verify the BCS scaling of the zero temperature gaps to the transition temperature. We observe that the self-energy effects are very crucial in order to reduce the resolution scale dependence of the results, while the three-body effects at the leading order do not change the two-body resolution scale depdendence. On the other hand, the results depend strongly on the three-body cut-off, emphasizing the importance of the missing higher-order three-body effects. We also observe that self-energy effects reduce the overall gap as well as shift the gap closure to lower densities.

  3. Localization of aerial pure tones by pinnipeds.

    PubMed

    Holt, Marla M; Schusterman, Ronald J; Kastak, David; Southall, Brandon L

    2005-12-01

    In this study, minimum audible angles (MAAs) of aerial pure tones were measured in and compared between a northern elephant seal (Mirounga angustirostris), a harbor seal (Phoca vitulina), and a California sea lion (Zalophus californianus). Testing was conducted between 0.8 and 16 kHz in the elephant seal and 0.8 and 20 kHz in the harbor seal and sea lion in a hemi-anechoic chamber using a left/right psychophysical procedure. Performance for the same frequencies was also quantified for discrete speaker separation of 5 degrees from the mid-line. For all subjects, MAAs ranged from approximately 3 degrees to 15 degrees and were generally equal to or larger than those previously measured in the same subjects with a broadband signal. Performance at 5 degrees ranged from chance to 97% correct, depending on frequency and subject. Poorest performance in the sea lion and harbor seal occurred at intermediate frequencies, which is consistent with the duplex theory of sound localization. In contrast, the elephant seal's poorest performance occurred at higher frequencies. The elephant seal's result suggests an inferior ability to utilize interaural level differences and is perhaps related to best hearing sensitivity shifted toward lower frequencies in this species relative to other pinnipeds.

  4. Particle Transport in Pure Electron Plasmas.

    NASA Astrophysics Data System (ADS)

    Kriesel, J. M.; Driscoll, C. F.

    1998-10-01

    At UCSD we confine pure-electron plasmas in Penning-Malmberg traps, which consist of cylindrical electrodes in an axial magnetic field (B ~ 100G). The trap is under ultra-high vacuum (10-10 Torr) so that transport due to electron-neutral collisions is negligible. Instead, cross-field particle transport is due to electron-electron collsions or from interactions with external fields. A plasma in one of our traps is roughly cylindrical in shape and rotates about its own axis due to the E x B drift from the space-charge field. Electron-electron collisions bring the plasma to a thermal equilibrium state of rigid rotation and uniform temperature. We find that the transport is driven by shears in the rotation velocity, and measure a coefficient of viscosity which is as much as 10,000 times larger than classical theory. This transport is driven by long-range ``E × B drift Coulomb collisions'' with impact parameters on the order of a Debye length rather than a cyclotron radius, as in classical theory. In our plasmas λD >> r_c, and O'Neil and Dubin have developed theories(Daniel H.E. Dubin, Phys. Plasmas 5), 1688 (1998) of transport in this regime. In addition to this work, I will also present measurements on the transport due to externally applied fields. The scalings provide insight into the overall confinement properties of our traps.

  5. Foaming of mixtures of pure hydrocarbons

    NASA Technical Reports Server (NTRS)

    Robinson, J. V.; Woods, W. W.

    1950-01-01

    Mixtures of pure liquid hydrocarbons are capable of foaming. Nine hydrocarbons were mixed in pairs, in all possible combinations, and four proportions of each combination. These mixtures were sealed in glass tubes, and the foaming was tested by shaking. Mixtures of aliphatic with other aliphatic hydrocarbons, or of alkyl benzenes with other alkyl benzenes, did not foam. Mixtures of aliphatic hydrocarbons with alkyl benzenes did foam. The proportions of the mixtures greatly affected the foaming, the maximum foaming of 12 of 20 pairs being at the composition 20 percent aliphatic hydrocarbon, 80 percent alkyl benzene. Six seconds was the maximum foam lifetime of any of these mixtures. Aeroshell 120 lubricating oil was fractionated into 52 fractions and a residue by extraction with acetone in a fractionating extractor. The index of refraction, foam lifetime, color, and viscosity of these fractions were measured. Low viscosity and high index fractions were extracted first. The viscosity of the fractions extracted rose and the index decreased as fractionation proceeded. Foam lifetimes and color were lowest in the middle fractions. Significance is attached to the observation that none of the foam lifetimes of the fractions or residue is as high as the foam lifetime of the original Aeroshell, indicating that the foaming is not due to a particular foaming constituent, but rather to the entire mixture.

  6. Localization of aerial pure tones by pinnipeds

    NASA Astrophysics Data System (ADS)

    Holt, Marla M.; Schusterman, Ronald J.; Kastak, David; Southall, Brandon L.

    2005-12-01

    In this study, minimum audible angles (MAAs) of aerial pure tones were measured in and compared between a northern elephant seal (Mirounga angustirostris), a harbor seal (Phoca vitulina), and a California sea lion (Zalophus californianus). Testing was conducted between 0.8 and 16 kHz in the elephant seal and 0.8 and 20 kHz in the harbor seal and sea lion in a hemi-anechoic chamber using a left/right psychophysical procedure. Performance for the same frequencies was also quantified for discrete speaker separation of 5° from the mid-line. For all subjects, MAAs ranged from approximately 3° to 15° and were generally equal to or larger than those previously measured in the same subjects with a broadband signal. Performance at 5° ranged from chance to 97% correct, depending on frequency and subject. Poorest performance in the sea lion and harbor seal occurred at intermediate frequencies, which is consistent with the duplex theory of sound localization. In contrast, the elephant seal's poorest performance occurred at higher frequencies. The elephant seal's result suggests an inferior ability to utilize interaural level differences and is perhaps related to best hearing sensitivity shifted toward lower frequencies in this species relative to other pinnipeds.

  7. Three new enantiomerically pure ferrocenylphosphole compounds.

    PubMed

    López Cortés, José Guadalupe; Vincendeau, Sandrine; Daran, Jean Claude; Manoury, Eric; Gouygou, Maryse

    2006-05-01

    The absolute configurations of three new enantiomerically pure ferrocenylphosphole compounds, namely (2S,4S,S(Fc))-4-methoxymethyl-2-[2-(9-thioxo-9lambda5-phosphafluoren-9-yl)ferrocenyl]-1,3-dioxane, [Fe(C5H5)(C23H22O3PS)], (III), (S(Fc))-[2-(9-thioxo-9lambda5-phosphafluoren-9-yl)ferrocenyl]methanol, [Fe(C5H5)(C18H14OPS)], (V), and (S(Fc))-diphenyl[2-(9-thioxo-9lambda5-phosphafluoren-9-yl]ferrocenylmethyl]phosphine, [Fe(C5H5)(C30H23P2)], (VIII), have been unambiguously established. All three ligands contain a planar chiral ferrocene group, bearing a dibenzophosphole and either a dioxane, a methanol or a diphenylphosphinomethane group on the same cyclopentadienyl. In compound (V), the occurrence of O-H...S and C-H...S hydrogen bonds results in the formation of a two-dimensional network parallel to (001). The geometry of the ferrocene frameworks agrees with related reported structures.

  8. Pure gauge spin-orbit couplings

    NASA Astrophysics Data System (ADS)

    Shikakhwa, M. S.

    2017-01-01

    Planar systems with a general linear spin-orbit interaction (SOI) that can be cast in the form of a non-Abelian pure gauge field are investigated using the language of non-Abelian gauge field theory. A special class of these fields that, though a 2×2 matrix, are Abelian are seen to emerge and their general form is given. It is shown that the unitary transformation that gauges away these fields induces at the same time a rotation on the wave function about a fixed axis but with a space-dependent angle, both of which being characteristics of the SOI involved. The experimentally important case of equal-strength Rashba and Dresselhaus SOI (R+D SOI) is shown to fall within this special class of Abelian gauge fields, and the phenomenon of persistent spin helix (PSH) that emerges in the presence of this latter SOI in a plane is shown to fit naturally within the general formalism developed. The general formalism is also extended to the case of a particle confined to a ring. It is shown that the Hamiltonian on a ring in the presence of equal-strength R+D SOI is unitarily equivalent to that of a particle subject to only a spin-independent but θ-dependent potential with the unitary transformation relating the two being again the space-dependent rotation operator characteristic of R+D SOI.

  9. Twofold symmetries of the pure gravity action

    DOE PAGES

    Cheung, Clifford; Remmen, Grant N.

    2017-01-25

    Here, we recast the action of pure gravity into a form that is invariant under a twofold Lorentz symmetry. To derive this representation, we construct a general parameterization of all theories equivalent to the Einstein-Hilbert action up to a local field redefinition and gauge fixing. We then exploit this freedom to eliminate all interactions except those exhibiting two sets of independently contracted Lorentz indices. The resulting action is local, remarkably simple, and naturally expressed in a field basis analogous to the exponential parameterization of the nonlinear sigma model. The space of twofold Lorentz invariant field redefinitions then generates an infinitemore » class of equivalent representations. By construction, all off-shell Feynman diagrams are twofold Lorentz invariant while all on-shell tree amplitudes are automatically twofold gauge invariant. We extend our results to curved spacetime and calculate the analogue of the Einstein equations. Finally, while these twofold invariances are hidden in the canonical approach of graviton perturbation theory, they are naturally expected given the double copy relations for scattering amplitudes in gauge theory and gravity.« less

  10. Degradable quantum channels using pure-state to product-of-pure-state isometries

    NASA Astrophysics Data System (ADS)

    Siddhu, Vikesh; Griffiths, Robert B.

    2016-11-01

    We consider a family of quantum channels characterized by the fact that certain (in general nonorthogonal) pure states at the channel entrance are mapped to (tensor) products of pure states (PPP; hence "pcubed") at the complementary outputs (the main output and the "environment") of the channel. The pcubed construction, a reformulation of the twisted-diagonal procedure by M. M. Wolf and D. Pérez-García [Phys. Rev. A 75, 012303 (2007)], 10.1103/PhysRevA.75.012303, can be used to produce a large class of degradable quantum channels; degradable channels are of interest because their quantum capacities are easy to calculate. Several known types of degradable channels are either pcubed channels, or subchannels (employing a subspace of the channel entrance), or continuous limits of pcubed channels. The pcubed construction also yields channels which are neither degradable nor antidegradable (i.e., the complement of a degradable channel); a particular example of a qutrit channel of this type is studied in some detail. Determining whether a pcubed channel is degradable or antidegradable or neither is quite straightforward given the pure input and output states that characterize the channel. Conjugate degradable pcubed channels are always degradable.

  11. [Studies on application of pure titanium for cast plate].

    PubMed

    Sakai, M

    1990-06-01

    Pure titanium produced by a commercial pure titanium casting system was studied for use as a cast plate for clinical application. The mechanical properties, elemental analysis, castability, adaptability of pure titanium and adhesion to denture base resin were investigated. The interfacial zone of the pure titanium castings was composed of a layered structure obtained by reaction with phosphate bonded Al2O3/SiO2 investment material. Vicher's hardness at 100 microns thick from the surface was higher than that in the inner part by oxidation. Cast pure titanium showed tensile strength, elongation and hardness close to those of the type III or IV dental gold alloy. The castability of pure titanium was lower than that of Co-Cr alloy and pure titanium castings also had large casting defects. Adaptability between pure titanium cast plate and the working model was satisfactory when reversible hydrocolloid impression material was used with heating-bath treatment in the refractory model. The tensile and compressive shear bonding strength of pure titanium to heat-curing or self-curing resin were similar to that of the Co-Cr alloy, and surface treatment using a solution containing 2-vol% 3-methacryloxypropyltrimethoxysilane produced a higher bonding strength than non-treatment, MKV treatment and 4-META treatment. These findings suggest that pure titanium castings produced by this system have suitable mechanical properties, adaptability and adhesion to denture base resin, and is available for cast plate in clinical application.

  12. Characterizing commercial pureed foods: sensory, nutritional, and textural analysis.

    PubMed

    Ettinger, Laurel; Keller, Heather H; Duizer, Lisa M

    2014-01-01

    Dysphagia (swallowing impairment) is a common consequence of stroke and degenerative diseases such as Parkinson's and Alzheimer's. Limited research is available on pureed foods, specifically the qualities of commercial products. Because research has linked pureed foods, specifically in-house pureed products, to malnutrition due to inferior sensory and nutritional qualities, commercial purees also need to be investigated. Proprietary research on sensory attributes of commercial foods is available; however direct comparisons of commercial pureed foods have never been reported. Descriptive sensory analysis as well as nutritional and texture analysis of commercially pureed prepared products was performed using a trained descriptive analysis panel. The pureed foods tested included four brands of carrots, of turkey, and two of bread. Each commercial puree was analyzed for fat (Soxhlet), protein (Dumas), carbohydrate (proximate analysis), fiber (total fiber), and sodium content (Quantab titrator strips). The purees were also texturally compared with a line spread test and a back extrusion test. Differences were found in the purees for sensory attributes as well as nutritional and textural properties. Findings suggest that implementation of standards is required to reduce variability between products, specifically regarding the textural components of the products. This would ensure all commercial products available in Canada meet standards established as being considered safe for swallowing.

  13. Pure-phase and pure-amplitude hologram design using the method of generalized projections

    NASA Astrophysics Data System (ADS)

    Catino, William Charles

    The overall contribution of the research presented in this dissertation is a systematic procedure for designing computer-generated holograms subject to far-field image constraints. The method of generalized projections is used to design pure-phase and pure-amplitude diffraction holograms that generate prescribed gray-scale images in the Fourier frequency plane. Performance is demonstrated with objective measures (error, efficiency, and variance), as well as with subjective comparison of images. Test images include a photographic quality image of Lena, a uniform intensity spot array, and a binary amplitude block text image. Projection algorithms are derived for pure-phase holograms with both continuous and quantized phase characteristics from a prescribed far-field magnitude constraint. The performance of the pure-phase hologram designs, as measured in the far-field image, is always very good for the continuous phase case and for the quantized phase case with a large number of phase quantization levels. However, as the number of quantization levels decreases, the performance typically degrades. Performance is significantly improved by constraining the energy in mutually exclusive cliques, that is, groups of image plane (far-field) pixels, instead of constraining the intensity of each individual pixel. Even for the binary phase case, acceptable images are generated with the clique energy algorithm. The method of generalized projections is also used to design pure-amplitude diffraction holograms using a prescribed image intensity constraint. Two algorithms are derived: the direct method, which nonlinearly constrains the hologram transmittance to the range of real values in (0,1); and the indirect method, which constrains the transmittance values to the real axis, and linearly transforms the resulting values to the range (0,1). Digital amplitude holograms are simulated by quantizing the amplitude holograms resulting from the indirect method. The indirect method

  14. Three-dimensional effects on pure tone fan noise due to inflow distortion. [rotor blade noise prediction

    NASA Technical Reports Server (NTRS)

    Kobayashi, H.

    1978-01-01

    Two dimensional, quasi three dimensional and three dimensional theories for the prediction of pure tone fan noise due to the interaction of inflow distortion with a subsonic annular blade row were studied with the aid of an unsteady three dimensional lifting surface theory. The effects of compact and noncompact source distributions on pure tone fan noise in an annular cascade were investigated. Numerical results show that the strip theory and quasi three-dimensional theory are reasonably adequate for fan noise prediction. The quasi three-dimensional method is more accurate for acoustic power and model structure prediction with an acoustic power estimation error of about plus or minus 2db.

  15. High-power, widely-tunable Cr(2+):ZnSemaster oscillator power amplifier systems.

    PubMed

    Berry, P A; Schepler, K L

    2010-07-05

    We demonstrate high-power Cr(2+):ZnSe master oscillator power amplifier (MOPA) pure continuous wave (CW) laser systems with output power of 14 W and amplifier gain greater than 2X. In addition, we develop a theoretical model for this type of amplification and show single-knob tunability at high powers over 400 nm.

  16. Parallel investigation of double forged pure tungsten samples irradiated in three DPF devices

    NASA Astrophysics Data System (ADS)

    Gribkov, V. A.; Paduch, M.; Zielinska, E.; Laas, T.; Shirokova, V.; Väli, B.; Paju, J.; Pimenov, V. N.; Demina, E. V.; Latyshev, S. V.; Niemela, J.; Crespo, M.-L.; Cicuttin, A.; Talab, A. A.; Pokatilov, A.; Parker, M.

    2015-08-01

    The double forged pure tungsten (W) samples (supplied by IAEA CRP from the FZJ team in Juelich, Germany) were irradiated in DPF (dense plasma focus) devices PF-12, "Bora" and PF-1000 by hot plasma and fast ion streams. We have used the following analytical methods: microscopy (optical and scanning electron), X-ray photoelectron spectroscopy, electrical conductivity and microroughness measurements. The damage dependence of the tungsten grades on irradiation conditions and power flux densities of irradiation processes is discussed.

  17. Pure SH-SAW propagation, transduction and measurements on KNbO3.

    PubMed

    Pollard, Thomas B; Kenny, Thomas D; Vetelino, John F; da Cunha, Mauricio Pereira

    2006-01-01

    Potassium niobate (KNbO3) supports the electromechanically active pure shear horizontal surface acoustic wave (SH-SAW) mode along Z-axis cylinder orientations, Euler angles (phi, 90 degrees, 0 degrees), in which two uncoupled wave solutions exist: a purely mechanical sagittal Rayleigh SAW and a piezoelectrically stiffened pure SH-SAW. Within this family of cuts, a maximum electromechanical coupling coefficient for the pure SH-SAW, K2 = 53%, is observed along (0 degrees, 90 degrees, 0 degrees). This pure SH-SAW orientation also has the maximum value of electromechanical coupling observed along rotated Y-cut X propagation directions, Euler angles (0 degrees, theta, 0 degrees). The use of the pure SH-SAW mode is attractive for liquid-sensing applications because the SH-SAW is modestly attenuated by the adjacent liquid, unlike the generalized SAW (GSAW), which has particle displacement normal to the surface. This work investigates propagation and excitation properties of the SH-SAW and the shear horizontal bulk acoustic wave (SH-BAW) on single crystal KNbO3, Euler angles (0 degrees, 90 degrees, 0 degrees). Interdigital transducer (IDT) arrays are analyzed using boundary element method (BEM) techniques, addressing IDT properties such as: power partitioning between the SH-SAW and SH-BAW, SH-BAW radiation as a function of wave vector direction and radiation angle, and overall IDT impedance. The percentage of SH-SAW power to total input power is above 98% for IDTs containing 1.5 to 5.5 wavelengths of active electrodes with surrounding metalized regions. For nonmetalized regions outside the IDT, the ratio drops to between 1 and 2%, showing the importance of an energy trapping structure for efficient SH-SAW excitation and propagation along this orientation. Simulated and experimental IDT admittance results are compared, verifying the validity of the analysis performed. The reported measurements on the frequency variation with temperature indicate that the orientation

  18. Predictions of pure liquid shock Hugoniots

    SciTech Connect

    Hobbs, M.L.; Baer, M.R.

    1998-06-01

    Determination of product species and associated equations-of-state (EOS) for energetic materials such as pyrotechnics with complex elemental compositions remains a major unsolved problem. Although, empirical EOS models may be calibrated to replicate detonation conditions within experimental variability (5--10%), different states, e.g. expansion, may produce significant discrepancy with data if the basic form of the EOS model is incorrect. A more physically realistic EOS model based on intermolecular potentials, such as the Jacobs Cowperthwaite Zwisler (JCZ3) EOS, is needed to predict detonation states as well as expanded states. Predictive capability for any EOS requires a large species data base composed of a wide variety of elements. Unfortunately, only 20 species have known exponential 6 (EXP 6) molecular force constants which are used in the JCZ3-EOS. Of these 20 species, only 10 have been adequately compared to experimental data such as molecular scattering or shock Hugoniot data. Since data in the strongly repulsive region of the molecular potential is limited, alternative methods must be found to deduce force constants for a larger number of species. The objective of the present study is to determine JCZ3 product species force constants using corresponding state theory. Intermolecular potential parameters were obtained for a variety of gas species using a simple corresponding states technique with critical volume and critical temperature. A more complex, four parameter corresponding state method with shape and polarity corrections was also used to obtain intermolecular potential parameters. Both corresponding state methods were used to predict shock Hugoniot data obtained from pure liquids. The simple corresponding state method is shown to give adequate agreement with shock Hugoniot data.

  19. Eruptive shearing of tube pumice: pure and simple

    NASA Astrophysics Data System (ADS)

    Dingwell, Donald B.; Lavallée, Yan; Hess, Kai-Uwe; Flaws, Asher; Marti, Joan; Nichols, Alexander R. L.; Gilg, H. Albert; Schillinger, Burkhard

    2016-09-01

    Understanding the physicochemical conditions extant and mechanisms operative during explosive volcanism is essential for reliable forecasting and mitigation of volcanic events. Rhyolitic pumices reflect highly vesiculated magma whose bubbles can serve as a strain indicator for inferring the state of stress operative immediately prior to eruptive fragmentation. Obtaining the full kinematic picture reflected in bubble population geometry has been extremely difficult, involving dissection of a small number of delicate samples. The advent of reliable high-resolution tomography has changed this situation radically. Here we demonstrate via the use of tomography how a statistically powerful picture of the shapes and connectivity of thousands of individual bubbles within a single sample of tube pumice emerges. The strain record of tube pumice is modelled using empirical models of bubble geometry and liquid rheology, reliant on a constraint of magmatic water concentration. FTIR analysis reveals an imbalance in water speciation, suggesting post-eruption hydration, further supported by hydrogen and oxygen isotope measurements. Our work demonstrates that the strain recorded in the tube pumice dominated by simple shear (not pure shear) in the late deformational history of vesicular magma before eruption. This constraint in turn implies that magma ascent is conditioned by a velocity gradient (across the conduit) at the point of origin of tube pumice. Magma ascent accompanied by simple shear should enhance high eruption rates inferred independently for these highly viscous systems.

  20. Temperature measurement error simulation of the pure rotational Raman lidar

    NASA Astrophysics Data System (ADS)

    Jia, Jingyu; Huang, Yong; Wang, Zhirui; Yi, Fan; Shen, Jianglin; Jia, Xiaoxing; Chen, Huabin; Yang, Chuan; Zhang, Mingyang

    2015-11-01

    Temperature represents the atmospheric thermodynamic state. Measure the atmospheric temperature accurately and precisely is very important to understand the physics of the atmospheric process. Lidar has some advantages in the atmospheric temperature measurement. Based on the lidar equation and the theory of pure rotational Raman (PRR), we've simulated the temperature measurement errors of the double-grating-polychromator (DGP) based PRR lidar. First of all, without considering the attenuation terms of the atmospheric transmittance and the range in the lidar equation, we've simulated the temperature measurement errors which are influenced by the beam splitting system parameters, such as the center wavelength, the receiving bandwidth and the atmospheric temperature. We analyzed three types of the temperature measurement errors in theory. We've proposed several design methods for the beam splitting system to reduce the temperature measurement errors. Secondly, we simulated the temperature measurement error profiles by the lidar equation. As the lidar power-aperture product is determined, the main target of our lidar system is to reduce the statistical and the leakage errors.

  1. Passive interferometric symmetries of multimode Gaussian pure states

    NASA Astrophysics Data System (ADS)

    Gabay, Natasha; Menicucci, Nicolas C.

    2016-05-01

    As large-scale multimode Gaussian states begin to become accessible in the laboratory, their representation and analysis become a useful topic of research in their own right. The graphical calculus for Gaussian pure states provides powerful tools for their representation, while this work presents a useful tool for their analysis: passive interferometric (i.e., number-conserving) symmetries. Here we show that these symmetries of multimode Gaussian states simplify calculations in measurement-based quantum computing and provide constructive tools for engineering large-scale harmonic systems with specific physical properties, and we provide a general mathematical framework for deriving them. Such symmetries are generated by linear combinations of operators expressed in the Schwinger representation of U (2 ) , called nullifiers because the Gaussian state in question is a zero eigenstate of them. This general framework is shown to have applications in the noise analysis of continuous-various cluster states and is expected to have additional applications in future work with large-scale multimode Gaussian states.

  2. A purely reflective large wide-field telescope

    NASA Astrophysics Data System (ADS)

    Terebizh, V. Yu.

    2008-06-01

    Two versions of a fast, purely reflective Paul-Baker-type telescope are discussed, each with an 8.4-m aperture, 3° diameter flat field and f/1.25 focal ratio. The first version is based on a common, even asphere type of surface with zero conic constant. The primary and tertiary mirrors are 6th order aspheres, while the secondary mirror is an 8th order asphere (referred to here for brevity, as the 6/8/6 configuration). The D 80 diameter of a star image varies from 0″.18 on the optical axis up to 0″.27 at the edge of the field (9.3-13.5 μm). The second version of the telescope is based on a polysag surface type, which uses a polynomial expansion in the sag z, r^2 = 2R_0 z - left( {1 + b} right)z^2 + a_3 z^3 + a_4 z^3 + a_4 z^4 + ldots + a_N z^N instead of the common form of aspheric surface. This approach results in somewhat better images, with D 80 ranging from 0″.16 to 0″.23, using a lower-order 3/4/3 combination of powers for the mirror surfaces. An additional example with 3.5-m aperture, 3°.5 diameter flat field, and f/1.25 focal ratio featuring near-diffraction-limited image quality is also presented.

  3. Entanglement bound for multipartite pure states based on local measurements

    SciTech Connect

    Jiang Lizhen; Chen Xiaoyu; Ye Tianyu

    2011-10-15

    An entanglement bound based on local measurements is introduced for multipartite pure states. It is the upper bound of the geometric measure and the relative entropy of entanglement. It is the lower bound of the minimal-measurement entropy. For pure bipartite states, the bound is equal to the entanglement entropy. The bound is applied to pure tripartite qubit states and the exact tripartite relative entropy of entanglement is obtained for a wide class of states.

  4. Thickness-dependent electronic structure modulation of ferromagnetic films on shape memory alloy substrates based on a pure strain effect

    NASA Astrophysics Data System (ADS)

    Feng, Chun; Hu, Di; Gong, Kui; Jiang, Xumin; Yin, Jianjuan; Cao, Yi; Tang, Xiao-Lei; Yang, Feng; Zhou, Zhongfu; Yu, Guanghua; Andrew Evans, D.

    2016-11-01

    Pure strain-induced electronic structure modulation in ferromagnetic films is critical for developing reliable strain-assisted spintronic devices with low power consumption. For the conventional electricity-controlled strain engineering, it is difficult to reveal the pure strain effect on electronic structure tunability due to the inseparability of pure strain effect and surface charge effect. Here, a non-electrically controlled NiTi shape memory alloy was utilized as a strain output substrate to induce a pure strain on attached Fe films through a thermally controlled shape memory effect. The pure strain induced electronic structure evolution was revealed by in-situ X-ray photoelectron spectroscopy and correlated with first-principles calculations and magnetic anisotropy measurements. A compressive strain enhances the shielding effect for core electrons and significantly tunes their binding energy. Meanwhile, the strain modifies the partial density of states of outer d orbits, which may affect spin-orbit coupling strength and related magnetic anisotropy. This work helps for clarifying the physical nature of the pure strain effect and developing the pure-strain-assisted spintronic devices.

  5. Typical pure nonequilibrium steady states and irreversibility for quantum transport.

    PubMed

    Monnai, Takaaki; Yuasa, Kazuya

    2016-07-01

    It is known that each single typical pure state in an energy shell of a large isolated quantum system well represents a thermal equilibrium state of the system. We show that such typicality holds also for nonequilibrium steady states (NESS's). We consider a small quantum system coupled to multiple infinite reservoirs. In the long run, the total system reaches a unique NESS. We identify a large Hilbert space from which pure states of the system are to be sampled randomly and show that the typical pure states well describe the NESS. We also point out that the irreversible relaxation to the unique NESS is important to the typicality of the pure NESS's.

  6. Pure endoscopic management of epileptogenic hypothalamic hamartomas.

    PubMed

    Chibbaro, S; Cebula, H; Scholly, J; Todeschi, J; Ollivier, I; Timofeev, A; Ganau, M; Di Emidio, P; Valenti, M P; Staack, A M; Bast, T; Steinhoff, B J; Hirsch, E; Kehrli, P; Proust, F

    2017-02-07

    Hypothalamic hamartomas (HH) are rare congenital malformations located in the region of the tuber cinereum and third ventricle. Their usual clinical presentation is characterized by gelastic/dacrystic seizures which often become pharmaco-resistant and progress to secondary focal/generalized intractable epilepsy causing mostly in children cognitive and behavioral problems (particularly in cases of progressive epileptic encephalopathy) and precocious puberty. Whereas gelastic seizures can be surgically controlled either by resection of the lesion or disconnection (tissue-destructive) procedures, aimed at functionally prevent the spreading of the epileptic burst; generalized seizures tend to respond better to HH excision rather than isolated neocortical resections, which generally fail to control them. Prospective analysis of 14 consecutive patients harboring HH treated in an 8-year period; 12 patients had unilateral and two bilateral HH. All patients were managed by pure endoscopic excision of the HH. The mean operative time was 48 min and mean hospital stay was 2 days; perioperative blood loss was negligible in all cases. Two patients showed a transient diabetes insipidus (DI); no transient or permanent postoperative neurological deficit or memory impairment was recorded. Complete HH excision was achieved in 10/14 patients. At a mean follow-up of 48 months, no wound infection, meningitis, postoperative hydrocephalus, and/or mortality were recorded in this series of patients. Eight patients became seizure free (Engel class I), 2 other experienced worthwhile improvement of disabling seizures (Engel class II); 2 patients were cured from gelastic attacks while still experiencing focal dyscognitive seizures; and 2, having bilateral HH (both undergoing unilateral HH excision), did not experience significant improvement and required later on a temporal lobectomy coupled to amygdalohyppocampectomy. Overall, the followings resulted to be predictive factors for better

  7. Pure Culture Fermentation of Green Olives1

    PubMed Central

    Etchells, J. L.; Borg, A. F.; Kittel, I. D.; Bell, T. A.; Fleming, H. P.

    1966-01-01

    The method previously developed by us for the pure-culture fermentation of brined cucumbers and other vegetables has been applied successfully to Manzanillo variety olives. Field-run grade fruit was processed first by conventional procedures to remove most of the bitterness. Then the relative abilities of Lactobacillus plantarum, L. brevis, Pediococcus cerevisiae, and Leuconostoc mesenteroides to become established and produce acid in both heat-shocked (74 C for 3 min) and unheated olives, brined at 4.7 to 5.9% NaCl (w/v basis), were evaluated. The heat-shock treatment not only proved effective in ridding the fruit of naturally occurring, interfering, and competitive microbial groups prior to brining and inoculation, but also made the olives highly fermentable with respect to growth and acid production by the introduced culture, particularly L. plantarum. Of the four species used as inocula, L. plantarum was by far the most vigorous in fermentation ability. It consistently produced the highest levels of brine acidity (1.0 to 1.2% calculated as lactic acid) and the lowest pH values (3.8 to 3.9) during the fermentation of heat-shocked olives. Also, L. plantarum completely dominated fermentations when used in two-species (with P. cerevisiae) and three-species (with P. cerevisiae and L. brevis) combinations as inocula. In contrast, when L. plantarum was inoculated into the brines of unheated olives it failed to become properly established; the same was true for the other species tested, but even to a more pronounced degree. L. brevis was the only species used that failed to develop in brines of both heat-shocked and unheated olives. Modification of the curing brine by the addition of lactic acid at the outset, either with or without dextrose, led to a much earlier onset of fermentation with accompanying acid development, as compared to treatments with dextrose alone or nonadditive controls. Reasons for the marked improvement of the fermentability of Manzanillo olives

  8. Power system extreme event screening using graphpartitioning

    SciTech Connect

    Lesieutre, Bernard C.; Roy, Sandip; Donde, Vaibhav; Pinar, Ali

    2006-09-06

    We propose a partitioning problem in a power system contextthat weighs the two objectives of minimizing cuts between partitions andmaximizing the power imbalance between partitions. We then pose theproblem in a purely graph theoretic sense. We offer an approximatesolution through relaxation of the integer problem and suggest refinementusing stochastic methods. Results are presented for the IEEE 30-bus and118-bus electric power systems.

  9. Anisotropic Absorption of Pure Spin Currents

    NASA Astrophysics Data System (ADS)

    Baker, A. A.; Figueroa, A. I.; Love, C. J.; Cavill, S. A.; Hesjedal, T.; van der Laan, G.

    2016-01-01

    Spin transfer in magnetic multilayers offers the possibility of ultrafast, low-power device operation. We report a study of spin pumping in spin valves, demonstrating that a strong anisotropy of spin pumping from the source layer can be induced by an angular dependence of the total Gilbert damping parameter, α , in the spin sink layer. Using lab- and synchrotron-based ferromagnetic resonance, we show that an in-plane variation of damping in a crystalline Co50 Fe50 layer leads to an anisotropic α in a polycrystalline Ni81 Fe19 layer. This anisotropy is suppressed above the spin diffusion length in Cr, which is found to be 8 nm, and is independent of static exchange coupling in the spin valve. These results offer a valuable insight into the transmission and absorption of spin currents, and a mechanism by which enhanced spin torques and angular control may be realized for next-generation spintronic devices.

  10. Pure Obsessive Compulsive Disorder in Three Generations

    PubMed Central

    Rahimi, Alireza; Haghighi, Mohammad; Shamsaei, Farshid

    2015-01-01

    Introduction: Obsessive-compulsive disorder (OCD) is a psychiatric disorder, which has been shown to affect 2 - 3.5% of people, during their lifetimes. Identification of familial more homogenous characteristics of OCD may help to define relevant subtypes and increase the power of genetic and neurobiological studies of OCD. Case Presentation; This case report describes an adult woman suffering from symptoms of energy loss, insomnia, lack of appetite, and depressed mood. The patient history was positive for counting coercion. The patient’s genogram revealed counting coercion in three generations of her family. Conclusions: This case highlights the issue whether counting can be a distinctive feature among inflicted and not inflicted individuals, such as hoarding. Also, it is still unclear what is it really transferred; the vulnerability to disease, which is transferred among three generations, or the symptoms of counting itself, by genes. Further studies are required to answer the debates on this issue. PMID:26288641

  11. A complete solution for dissecting pure main and epistatic effects of QTL in triple testcross design.

    PubMed

    He, Xiao-Hong; Zhang, Yuan-Ming

    2011-01-01

    Epistasis plays an important role in genetics, evolution and crop breeding. To detect the epistasis, triple test cross (TTC) design had been developed several decades ago. Classical procedures for the TTC design use only linear transformations Z(1), Z(2) and Z(3), calculated from the TTC family means of quantitative trait, to infer the nature of the collective additive, dominance and epistatic effects of all the genes. Although several quantitative trait loci (QTL) mapping approaches in the TTC design have been developed, these approaches do not provide a complete solution for dissecting pure main and epistatic effects. In this study, therefore, we developed a two-step approach to estimate all pure main and epistatic effects in the F(2)-based TTC design under the F(2) and F(∞) metric models. In the first step, with Z(1) and Z(2) the augmented main and epistatic effects in the full genetic model that simultaneously considered all putative QTL on the whole genome were estimated using empirical Bayes approach, and with Z(3) three pure epistatic effects were obtained using two-dimensional genome scans. In the second step, the three pure epistatic effects obtained in the first step were integrated with the augmented epistatic and main effects for the further estimation of all other pure effects. A series of Monte Carlo simulation experiments has been carried out to confirm the proposed method. The results from simulation experiments show that: 1) the newly defined genetic parameters could be rightly identified with satisfactory statistical power and precision; 2) the F(2)-based TTC design was superior to the F(2) and F(2:3) designs; 3) with Z(1) and Z(2) the statistical powers for the detection of augmented epistatic effects were substantively affected by the signs of pure epistatic effects; and 4) with Z(3) the estimation of pure epistatic effects required large sample size and family replication number. The extension of the proposed method in this study to other

  12. Physical and Spiritual Education within the Framework of Pure Life

    ERIC Educational Resources Information Center

    Bagheri Noaparast, Khosrow

    2013-01-01

    This paper aims at showing the dimensions of spirituality in childhood education by suggesting a new analysis of the concept of "pure life" used in the Qur'an. Putting spirituality in the framework of the pure life provides us with a rich framework in dealing with spirituality as the latter will be extended to all dimensions of a life. In the…

  13. 1. SOUTH AND WEST ELEVATION OF ILLINOIS PURE ALUMINUM (IPA) ...

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

    1. SOUTH AND WEST ELEVATION OF ILLINOIS PURE ALUMINUM (IPA) COMPANY FACTORY; SOUTH ELEVATION FACING ILLINOIS CENTRAL GULF RAILROAD TRACKS AND MAIN STREET. THE ONE-STORY BRICK BUILDING TO THE LEFT IS AN ABANDONED COMMONWEALTH EDISON COMPANY ELECTRICAL SUBSTATION. - Illinois Pure Aluminum Company, 109 Holmes Street, Lemont, Cook County, IL

  14. Physical and Spiritual Education within the Framework of Pure Life

    ERIC Educational Resources Information Center

    Bagheri Noaparast, Khosrow

    2013-01-01

    This paper aims at showing the dimensions of spirituality in childhood education by suggesting a new analysis of the concept of "pure life" used in the Qur'an. Putting spirituality in the framework of the pure life provides us with a rich framework in dealing with spirituality as the latter will be extended to all dimensions of a life. In the…

  15. Auditory Repetition Priming Is Impaired in Pure Alexic Patients

    ERIC Educational Resources Information Center

    Swick, Diane; Miller, Kimberly M.; Larsen, Jary

    2004-01-01

    Alexia without agraphia, or ''pure'' alexia, is an acquired impairment in reading that leaves writing skills intact. Repetition priming for visually presented words is diminished in pure alexia. However, it is not possible to verify whether this priming deficit is modality-specific or modality independent because reading abilities are compromised.…

  16. Keeping consumers safe: food providers' perspectives on pureed food.

    PubMed

    Keller, Heather H; Duizer, Lisa M

    2014-01-01

    Twelve focus groups were conducted in five sites with 80 allied health providers to identify their perspectives on providing pureed food to consumers. Thematic care analysis was completed to summarize and interpret these data. Providers' greatest concern was keeping consumers safe, and the right texture was prioritized over sensory appeal and acceptance. Providers recognized that these foods impacted the quality of life of consumers and worked to rationalize these diets with residents/patients and their families. In addition, offering foods they knew to be poorly accepted affected their self-concept as providers. As a result of these challenges, they did whatever they could in the kitchen and tableside to promote intake of pureed foods. Those in the "food chain" of pureed food provision suggested several ways to further improve these products. Greater communication between those who assist consumers with eating and those who produce the pureed food they consume is needed to promote acceptable pureed products.

  17. Fluctuation solution theory of pure fluids

    NASA Astrophysics Data System (ADS)

    Ploetz, Elizabeth A.; Pallewela, Gayani N.; Smith, Paul E.

    2017-03-01

    Fluctuation Solution Theory (FST) provides an alternative view of fluid thermodynamics in terms of pair fluctuations in the particle number and excess energy observed for an equivalent open system. Here we extend the FST approach to provide a series of triplet and quadruplet particle and excess energy fluctuations that can also be used to help understand the behavior of fluids. The fluctuations for the gas, liquid, and supercritical regions of three fluids (H2O, CO2, and SF6) are then determined from accurate equations of state. Many of the fluctuating quantities change sign on moving from the gas to liquid phase and, therefore, we argue that the fluctuations can be used to characterize gas and liquid behavior. Further analysis provides an approach to isolate contributions to the excess energy fluctuations arising from just the intermolecular interactions and also indicates that the triplet and quadruplet particle fluctuations are related to the pair particle fluctuations by a simple power law for large regions of the phase diagram away from the critical point.

  18. Photonuclear activation of pure isotopic mediums.

    SciTech Connect

    Grohman, Mark A.; Lukosi, Eric Daniel

    2010-06-01

    This work simulated the response of idealized isotopic U-235, U-238, Th-232, and Pu-239 mediums to photonuclear activation with various photon energies. These simulations were conducted using MCNPX version 2.6.0. It was found that photon energies between 14-16 MeV produce the highest response with respect to neutron production rates from all photonuclear reactions. In all cases, Pu-239 responds the highest, followed by U-238. Th-232 produces more overall neutrons at lower photon energies then U-235 when material thickness is above 3.943 centimeters. The time it takes each isotopic material to reach stable neutron production rates in time is directly proportional to the material thickness and stopping power of the medium, where thicker mediums take longer to reach stable neutron production rates and thinner media display a neutron production plateau effect, due to the lack of significant attenuation of the activating photons in the isotopic mediums. At this time, no neutron sensor system has time resolutions capable of verifying these simulations, but various indirect methods are possible and should be explored for verification of these results.

  19. [The left central gyral lesion and pure anarthria].

    PubMed

    Tabuchi, M; Odashima, K; Fujii, T; Suzuki, K; Saitou, J; Yamadori, A

    2000-05-01

    We report a very rare case of pure anarthria with lesion analysis. A 44-year-old right-handed man suffered from a cerebral infarction with a mild right hemiparesis and speech disturbance. An MRI of the brain 1.5 months post onset revealed a lesion confined to the left central gyrus. One month after the onset, his spontaneous speech was dysprosodic and laborious. It was contaminated with dysarthria and phonological paraphasias. However, language comprehension, repetition and naming abilities were normal. Most remarkably he showed no impairment in writing with his left hand. Over the following months, his difficulties in verbal output showed general amelioration, but the isolated impairment in the domain of articulation characterized by dysprosody, dysarthria, and phonological paraphasia persisted. As for the symptomatology of pure anarthria resulting from precentral gyral lesions, there have been controversies about its pureness. Some argue that the so called pure anarthria always shows some degree of writing disturbances, albeit mild in degree. Others maintain there certainly exists the pure type without any signs of agraphia. In the present case lesions were limited to the central gyrus but spared the lowest opercular portion. The previous reports of pure anarthria that had mild agraphia all had lesions involving the opercular portion. We conclude the sparing of this area is most likely related with sparing of writing capacity in pure anarthria.

  20. Cyclic Creep of Ultrafine-Grained Pure Cu Under Cyclic Tension Deformation

    NASA Astrophysics Data System (ADS)

    Wu, Yanjun; Yang, Jingwen; Shen, Xu; Zhu, Rong

    2017-02-01

    The uniaxial ratcheting behavior of ultrafine-grained pure Cu processed by equal-channel angular pressing (ECAP) was investigated through uniaxial asymmetric cyclic stress-controlled experiments at room temperature. The effects of the mean stress and stress amplitude on the uniaxial ratcheting response and ratcheting life of the ECAP Cu were analyzed. With increasing mean stress or stress amplitude, the ratcheting strain and its rate increased, but the ratcheting life decreased. An approach based on Basquin's method was used to describe the fatigue lifetime of the ECAP pure Cu. Additionally, a power law relationship was adopted to describe the cyclic steady creep rate. Finally, the microscopic and macroscopic fracture features were examined. It was found that at high peak stresses, cyclic creep governs the overall failure process; otherwise, cyclic creep-fatigue interaction is the dominant failure mode.

  1. Laser Surface Alloying of Copper, Manganese, and Magnesium with Pure Aluminum Substrate

    NASA Astrophysics Data System (ADS)

    Jiru, Woldetinsay G.; Sankar, M. Ravi; Dixit, Uday S.

    2016-03-01

    Laser surface alloying is one of the recent technologies used in the manufacturing sector for improving the surface properties of the metals. Light weight materials like aluminum alloys, titanium alloys, and magnesium alloys are used in the locomotive, aerospace, and structural applications. In the present work, an experimental study was conducted to improve the surface hardness of commercially pure aluminum plate. CO2 laser is used to melt pre-placed powders of pure copper, manganese, and magnesium. Microstructure of alloyed surface was analyzed using optical microscope. The best surface alloying was obtained at the optimum values of laser parameters, viz., laser power, scan speed, and laser beam diameter. In the alloyed region, microhardness increased from 30 HV0.5 to 430 HV0.5, while it was 60 HV0.5 in the heat-affected region. Tensile tests revealed some reduction in the strength and total elongation due to alloying. On the other hand, corrosion resistance improved.

  2. Shunting arc plasma source for pure carbon ion beam.

    PubMed

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse.

  3. Effect of humidity on fretting wear of several pure metals

    NASA Technical Reports Server (NTRS)

    Goto, H.; Buckley, D. H.

    1984-01-01

    Fretting wear experiments with several pure metals were conducted in air at various relative humidity levels. The materials used were iron, aluminum, copper, silver, chromium, titanium, and nickel. Each pure metal had a maximum fretting wear volume at a specific humidity level RH sub max that was not dependent on mechanical factors such as contact load, fretting amplitude, and frequency in the ranges studied. The weight loss due to fretting wear at RH sub max for each pure metal decreased with increasing heat of oxygen adsorption on the metal, indicating that adhesive wear dominated at RH sub max.

  4. Shunting arc plasma source for pure carbon ion beama)

    NASA Astrophysics Data System (ADS)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y.

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm2 at the peak of the pulse.

  5. Faster and cleaner real-time pure shift NMR experiments.

    PubMed

    Mauhart, Johannes; Glanzer, Simon; Sakhaii, Peyman; Bermel, Wolfgang; Zangger, Klaus

    2015-10-01

    Real-time pure shift experiments provide highly resolved proton NMR spectra which do not require any special processing. Although being more sensitive than their pseudo 2D counterparts, their signal intensities per unit time are still far below regular NMR spectra. In addition, scalar coupling evolution during the individual data chunks produces decoupling sidebands. Here we show that faster and cleaner real-time pure shift spectra can be obtained through the implementation of two parameter alterations. Variation of the FID chunk lengths between individual transients significantly suppresses decoupling sidebands for any kind of real-time pure shift spectra and thus allows for example the analysis of minor components in compound mixtures. Shifting the excitation frequency between individual scans of real-time slice-selective pure shift spectra increases their sensitivity obtainable in unit time by allowing faster repetitions of acquisitions.

  6. Gravitation, Electromagnetism and the Cosmological Constant in Purely Affine Gravity

    NASA Astrophysics Data System (ADS)

    Popławski, Nikodem J.

    The Eddington Lagrangian in the purely affine formulation of general relativity generates the Einstein equations with the cosmological constant. The Ferraris-Kijowski purely affine Lagrangian for the electromagnetic field, which has the form of the Maxwell Lagrangian with the metric tensor replaced by the symmetrized Ricci tensor, is dynamically equivalent to the Einstein-Maxwell Lagrangian in the metric formulation. We show that the sum of the two affine Lagrangians is dynamically inequivalent to the sum of the analogous Lagrangians in the metric-affine/metric formulation. We also show that such a construction is valid only for weak electromagnetic fields. Therefore the purely affine formulation that combines gravitation, electromagnetism and the cosmological constant cannot be a simple sum of terms corresponding to separate fields. Consequently, this formulation of electromagnetism seems to be unphysical, unlike the purely metric and metric-affine pictures, unless the electromagnetic field couples to the cosmological constant.

  7. Production of fermented chestnut purees by lactic acid bacteria.

    PubMed

    Blaiotta, G; Di Capua, M; Coppola, R; Aponte, M

    2012-09-03

    The objective of this study was to develop a new chestnut-based puree, in order to seasonally adjust the offer and use the surplus of undersized production, providing, at the same time, a response to the growing demand for healthy and environmentally friendly products. Broken dried chestnuts have been employed to prepare purees to be fermented with six different strains of Lactobacillus (Lb.) rhamnosus and Lactobacillus casei. The fermented purees were characterized by a technological and sensorial point of view, while the employed strains were tested for their probiotic potential. Conventional in vitro tests have indicated the six lactobacilli strains as promising probiotic candidates; moreover, being the strains able to grow and to survive in chestnut puree at a population level higher than 8 log₁₀ CFU/mL along 40 days of storage at 4 °C, the bases for the production of a new food, lactose-free and with reduced fat content, have been laid.

  8. The theoretical polarization of pure scattering axisymmetric circumstellar envelopes

    NASA Technical Reports Server (NTRS)

    Fox, G. K.

    1994-01-01

    The Sobolev approach to the scattering of starlight through a pure scattering circumstellar envelope is developed. The theoretical polarization due to electron scattering in Be star envelopes is calculated for two geometries (an equatorially enhanced envelope and a spheroidal envelope). Only the disk-type envelope is found to yield a maximum polarization consistent with the observed range for Be stars. A lower limit, analytical approximation to the theoretical polarization from a pure scattering envelope is obtained.

  9. All entangled pure states violate a single Bell's inequality.

    PubMed

    Yu, Sixia; Chen, Qing; Zhang, Chengjie; Lai, C H; Oh, C H

    2012-09-21

    We show that a single Bell's inequality with two dichotomic observables for each observer, which originates from Hardy's nonlocality proof without inequalities, is violated by all entangled pure states of a given number of particles, each of which may have a different number of energy levels. Thus Gisin's theorem is proved in its most general form from which it follows that for pure states Bell's nonlocality and quantum entanglement are equivalent.

  10. Physics of pure and non-pure positron emitters for PET: a review and a discussion.

    PubMed

    Conti, Maurizio; Eriksson, Lars

    2016-12-01

    With the increased interest in new PET tracers, gene-targeted therapy, immunoPET, and theranostics, other radioisotopes will be increasingly used in clinical PET scanners, in addition to (18)F. Some of the most interesting radioisotopes with prospective use in the new fields are not pure short-range β(+) emitters but can be associated with gamma emissions in coincidence with the annihilation radiation (prompt gamma), gamma-gamma cascades, intense Bremsstrahlung radiation, high-energy positrons that may escape out of the patient skin, and high-energy gamma rays that result in some e (+)/e (-) pair production. The high level of sophistication in data correction and excellent quantitative accuracy that has been reached for (18)F in recent years can be questioned by these effects. In this work, we review the physics and the scientific literature and evaluate the effect of these additional phenomena on the PET data for each of a series of radioisotopes: (11)C, (13)N, (15)O, (18)F, (64)Cu, (68)Ga, (76)Br, (82)Rb, (86)Y, (89)Zr, (90)Y, and (124)I. In particular, we discuss the present complications arising from the prompt gammas, and we review the scientific literature on prompt gamma correction. For some of the radioisotopes considered in this work, prompt gamma correction is definitely needed to assure acceptable image quality, and several approaches have been proposed in recent years. Bremsstrahlung photons and (176)Lu background were also evaluated.

  11. A zero-power radio receiver.

    SciTech Connect

    Brocato, Robert Wesley

    2004-09-01

    This report describes both a general methodology and some specific examples of passive radio receivers. A passive radio receiver uses no direct electrical power but makes sole use of the power available in the radio spectrum. These radio receivers are suitable as low data-rate receivers or passive alerting devices for standard, high power radio receivers. Some zero-power radio architectures exhibit significant improvements in range with the addition of very low power amplifiers or signal processing electronics. These ultra-low power radios are also discussed and compared to the purely zero-power approaches.

  12. Pure-tone birdsong by resonance filtering of harmonic overtones

    NASA Astrophysics Data System (ADS)

    Beckers, Gabriël J. L.; Suthers, Roderick A.; Ten Cate, Carel

    2003-06-01

    Pure-tone song is a common and widespread phenomenon in birds. The mechanistic origin of this type of phonation has been the subject of long-standing discussion. Currently, there are three hypotheses. (i) A vibrating valve in the avian vocal organ, the syrinx, generates a multifrequency harmonic source sound, which is filtered to a pure tone by a vocal tract filter ("source-filter" model, analogous to human speech production). (ii) Vocal tract resonances couple with a vibrating valve source, suppressing the normal production of harmonic overtones at this source ("soprano" model, analogous to human soprano singing). (iii) Pure-tone sound is produced as such by a sound-generating mechanism that is fundamentally different from a vibrating valve. Here we present direct evidence of a source-filter mechanism in the production of pure-tone birdsong. Using tracheal thermistors and air sac pressure cannulae, we recorded sound signals close to the syringeal sound source during spontaneous, pure-tone vocalizations of two species of turtledove. The results show that pure-tone dove vocalizations originate through filtering of a multifrequency harmonic sound source.

  13. Testing effects in mixed- versus pure-list designs.

    PubMed

    Rowland, Christopher A; Littrell-Baez, Megan K; Sensenig, Amanda E; DeLosh, Edward L

    2014-08-01

    In the present study, we investigated the role of list composition in the testing effect. Across three experiments, participants learned items through study and initial testing or study and restudy. List composition was manipulated, such that tested and restudied items appeared either intermixed in the same lists (mixed lists) or in separate lists (pure lists). In Experiment 1, half of the participants received mixed lists and half received pure lists. In Experiment 2, all participants were given both mixed and pure lists. Experiment 3 followed Erlebacher's (Psychological Bulletin, 84, 212-219, 1977) method, such that mixed lists, pure tested lists, and pure restudied lists were given to independent groups. Across all three experiments, the final recall results revealed significant testing effects for both mixed and pure lists, with no reliable difference in the magnitude of the testing advantage across list designs. This finding suggests that the testing effect is not subject to a key boundary condition-list design-that impacts other memory phenomena, including the generation effect.

  14. A Simple Protein Synthesis Model for the PURE System Operation.

    PubMed

    Mavelli, Fabio; Marangoni, Roberto; Stano, Pasquale

    2015-06-01

    The encapsulation of transcription-translation (TX-TL) cell-free machinery inside lipid vesicles (liposomes) is a key element in synthetic cell technology. The PURE system is a TX-TL kit composed of well-characterized parts, whose concentrations are fine tunable, which works according to a modular architecture. For these reasons, the PURE system perfectly fulfils the requirements of synthetic biology and is widely used for constructing synthetic cells. In this work, we present a simplified mathematical model to simulate the PURE system operations. Based on Michaelis-Menten kinetics and differential equations, the model describes protein synthesis dynamics by using 9 chemical species, 6 reactions and 16 kinetic parameters. The model correctly predicts the time course for messenger RNA and protein production and allows quantitative predictions. By means of this model, it is possible to foresee how the PURE system species affect the mechanism of proteins synthesis and therefore help in understanding scenarios where the concentration of the PURE system components has been modified purposely or as a result of stochastic fluctuations (for example after random encapsulation inside vesicles). The model also makes the determination of response coefficients for all species involved in the TX-TL mechanism possible and allows for scrutiny on how chemical energy is consumed by the three PURE system modules (transcription, translation and aminoacylation).

  15. Fracture behaviors under pure shear loading in bulk metallic glasses.

    PubMed

    Chen, Cen; Gao, Meng; Wang, Chao; Wang, Wei-Hua; Wang, Tzu-Chiang

    2016-12-23

    Pure shear fracture test, as a special mechanical means, had been carried out extensively to obtain the critical information for traditional metallic crystalline materials and rocks, such as the intrinsic deformation behavior and fracture mechanism. However, for bulk metallic glasses (BMGs), the pure shear fracture behaviors have not been investigated systematically due to the lack of a suitable test method. Here, we specially introduce a unique antisymmetrical four-point bend shear test method to realize a uniform pure shear stress field and study the pure shear fracture behaviors of two kinds of BMGs, Zr-based and La-based BMGs. All kinds of fracture behaviors, the pure shear fracture strength, fracture angle and fracture surface morphology, are systematically analyzed and compared with those of the conventional compressive and tensile fracture. Our results indicate that both the Zr-based and La-based BMGs follow the same fracture mechanism under pure shear loading, which is significantly different from the situation of some previous research results. Our results might offer new enlightenment on the intrinsic deformation and fracture mechanism of BMGs and other amorphous materials.

  16. PURE ribosome display and its application in antibody technology.

    PubMed

    Kanamori, Takashi; Fujino, Yasuhiro; Ueda, Takuya

    2014-11-01

    Ribosome display utilizes formation of the mRNA-ribosome-polypeptide ternary complex in a cell-free protein synthesis system to link genotype (mRNA) to phenotype (polypeptide). However, the presence of intrinsic components, such as nucleases in the cell-extract-based cell-free protein synthesis system, reduces the stability of the ternary complex, which would prevent attainment of reliable results. We have developed an efficient and highly controllable ribosome display system using the PURE (Protein synthesis Using Recombinant Elements) system. The mRNA-ribosome-polypeptide ternary complex is highly stable in the PURE system, and the selected mRNA can be easily recovered because activities of nucleases and other inhibitory factors are very low in the PURE system. We have applied the PURE ribosome display to antibody engineering approaches, such as epitope mapping and affinity maturation of antibodies, and obtained results showing that the PURE ribosome display is more efficient than the conventional method. We believe that the PURE ribosome display can contribute to the development of useful antibodies. This article is part of a Special Issue entitled: Recent advances in molecular engineering of antibody.

  17. Fracture behaviors under pure shear loading in bulk metallic glasses

    PubMed Central

    Chen, Cen; Gao, Meng; Wang, Chao; Wang, Wei-Hua; Wang, Tzu-Chiang

    2016-01-01

    Pure shear fracture test, as a special mechanical means, had been carried out extensively to obtain the critical information for traditional metallic crystalline materials and rocks, such as the intrinsic deformation behavior and fracture mechanism. However, for bulk metallic glasses (BMGs), the pure shear fracture behaviors have not been investigated systematically due to the lack of a suitable test method. Here, we specially introduce a unique antisymmetrical four-point bend shear test method to realize a uniform pure shear stress field and study the pure shear fracture behaviors of two kinds of BMGs, Zr-based and La-based BMGs. All kinds of fracture behaviors, the pure shear fracture strength, fracture angle and fracture surface morphology, are systematically analyzed and compared with those of the conventional compressive and tensile fracture. Our results indicate that both the Zr-based and La-based BMGs follow the same fracture mechanism under pure shear loading, which is significantly different from the situation of some previous research results. Our results might offer new enlightenment on the intrinsic deformation and fracture mechanism of BMGs and other amorphous materials. PMID:28008956

  18. Pure-tone birdsong by resonance filtering of harmonic overtones.

    PubMed

    Beckers, Gabriël J L; Suthers, Roderick A; ten Cate, Carel

    2003-06-10

    Pure-tone song is a common and widespread phenomenon in birds. The mechanistic origin of this type of phonation has been the subject of long-standing discussion. Currently, there are three hypotheses. (i) A vibrating valve in the avian vocal organ, the syrinx, generates a multifrequency harmonic source sound, which is filtered to a pure tone by a vocal tract filter ("source-filter" model, analogous to human speech production). (ii) Vocal tract resonances couple with a vibrating valve source, suppressing the normal production of harmonic overtones at this source ("soprano" model, analogous to human soprano singing). (iii) Pure-tone sound is produced as such by a sound-generating mechanism that is fundamentally different from a vibrating valve. Here we present direct evidence of a source-filter mechanism in the production of pure-tone birdsong. Using tracheal thermistors and air sac pressure cannulae, we recorded sound signals close to the syringeal sound source during spontaneous, pure-tone vocalizations of two species of turtledove. The results show that pure-tone dove vocalizations originate through filtering of a multifrequency harmonic sound source.

  19. Fracture behaviors under pure shear loading in bulk metallic glasses

    NASA Astrophysics Data System (ADS)

    Chen, Cen; Gao, Meng; Wang, Chao; Wang, Wei-Hua; Wang, Tzu-Chiang

    2016-12-01

    Pure shear fracture test, as a special mechanical means, had been carried out extensively to obtain the critical information for traditional metallic crystalline materials and rocks, such as the intrinsic deformation behavior and fracture mechanism. However, for bulk metallic glasses (BMGs), the pure shear fracture behaviors have not been investigated systematically due to the lack of a suitable test method. Here, we specially introduce a unique antisymmetrical four-point bend shear test method to realize a uniform pure shear stress field and study the pure shear fracture behaviors of two kinds of BMGs, Zr-based and La-based BMGs. All kinds of fracture behaviors, the pure shear fracture strength, fracture angle and fracture surface morphology, are systematically analyzed and compared with those of the conventional compressive and tensile fracture. Our results indicate that both the Zr-based and La-based BMGs follow the same fracture mechanism under pure shear loading, which is significantly different from the situation of some previous research results. Our results might offer new enlightenment on the intrinsic deformation and fracture mechanism of BMGs and other amorphous materials.

  20. Radiation effects on beta 10.6 of pure and europium doped KCl

    NASA Technical Reports Server (NTRS)

    Grimes, H. H.; Maisel, J. E.; Hartford, R. H.

    1975-01-01

    Changes in the optical absorption coefficient as a result of X-ray and electron bombardment of pure KCl (monocrystalline and polycrystalline), and divalent europium doped polycrystalline KCl were determined. The optical absorption coefficients were measured by a constant heat flow calorimetric method. Both 300 KV X-irradiation and 2 MeV electron irradiation produced significant increases in beta 10.6, measured at room temperature. The X-irradiation of pure moncrystalline KCl increased beta 10.6 by 0.005/cm for a 113 MR dose. For an equivalent dose, 2 MeV electrons were found less efficient in changing beta 10.6. However, electron irradiation of pure and Eu-doped polycrystalline KCl produced marked increases in adsorption. Beta increased to over 0.25/cm in Eu-doped material for a 30 x 10 to the 14th power electrons/sq cm dose, a factor of 20 increase over unirradiated material. Moreover, bleaching the electron irradiated doped KCl with 649 m light produced and additional factor of 1.5 increase. These findings will be discussed in light of known defect-center properties in KCl.

  1. Study on A.C. electrical properties of pure and L-serine doped ADP crystals

    NASA Astrophysics Data System (ADS)

    Joshi, J. H.; Dixit, K. P.; Joshi, M. J.; Parikh, K. D.

    2016-05-01

    Ammonium Dihydrogen Phosphate (ADP) crystals have a wide range of applications in integrated and nonlinear optics. Amino acids having significant properties like molecular chirality, zwitter ionic nature, etc. attracted many researchers to dope them in various NLO crystals. In the present study, pure and different weight percentage L-serine doped ADP crystals were grown by slow solvent evaporation technique at room temperature. The A.C. electrical study was carried out for palletized samples at room temperature. The Nyquist plot showed two semi circles for pure ADP indicated the effect of grain and grain boundary, whereas the doped ADP samples exhibited the single semi circle suggesting the effect of grain. The values resistance and capacitance for grain and grain boundary were calculated. The effect of doping was clearly seen in the grain capacitance and resistance values. The dielectric constant and dielectric loss decreased with increase in frequency for all samples. The Jonscher power law was applied for A.C. conductivity for pure and doped ADP samples. The imaginary part of modulus and impedance versus frequency were drawn and the value of stretch exponent (β) was calculated for all the samples.

  2. Impacts of pure shocks in the BHR71 bipolar outflow

    NASA Astrophysics Data System (ADS)

    Gusdorf, A.; Riquelme, D.; Anderl, S.; Eislöffel, J.; Codella, C.; Gómez-Ruiz, A. I.; Graf, U. U.; Kristensen, L. E.; Leurini, S.; Parise, B.; Requena-Torres, M. A.; Ricken, O.; Güsten, R.

    2015-03-01

    Context. During the formation of a star, material is ejected along powerful jets that impact the ambient material. This outflow regulates star formation by e.g. inducing turbulence and heating the surrounding gas. Understanding the associated shocks is therefore essential to the study of star formation. Aims: We present comparisons of shock models with CO, H2, and SiO observations in a "pure" shock position in the BHR71 bipolar outflow. These comparisons provide an insight into the shock and pre-shock characteristics, and allow us to understand the energetic and chemical feedback of star formation on Galactic scales. Methods: New CO (Jup = 16, 11, 7, 6, 4, 3) observations from the shocked regions with the SOFIA and APEX telescopes are presented and combined with earlier H2 and SiO data (from the Spitzer and APEX telescopes). The integrated intensities are compared to a grid of models that were obtained from a magneto-hydrodynamical shock code, which calculates the dynamical and chemical structure of these regions combined with a radiative transfer module based on the "large velocity gradient" approximation. Results: The CO emission leads us to update the conclusions of our previous shock analysis: pre-shock densities of 104 cm-3 and shock velocities around 20-25 km s-1 are still constrained, but older ages are inferred (~4000 years). Conclusions: We evaluate the contribution of shocks to the excitation of CO around forming stars. The SiO observations are compatible with a scenario where less than 4% of the pre-shock SiO belongs to the grain mantles. We infer outflow parameters: a mass of 1.8 × 10-2 M⊙ was measured in our beam, in which a momentum of 0.4 M⊙ km s-1 is dissipated, corresponding to an energy of 4.2 × 1043 erg. We analyse the energetics of the outflow species by species. Comparing our results with previous studies highlights their dependence on the method: H2 observations only are not sufficient to evaluate the mass of outflows.

  3. Nebular Emission Line Ratios in z ≃ 2–3 Star-forming Galaxies with KBSS-MOSFIRE: Exploring the Impact of Ionization, Excitation, and Nitrogen-to-Oxygen Ratio

    NASA Astrophysics Data System (ADS)

    Strom, Allison L.; Steidel, Charles C.; Rudie, Gwen C.; Trainor, Ryan F.; Pettini, Max; Reddy, Naveen A.

    2017-02-01

    We present a detailed study of the rest-optical (3600–7000 Å) nebular spectra of ∼380 star-forming galaxies at z≃ 2{--}3, obtained with Keck/Multi-object Spectrometer for Infrared Exploration (MOSFIRE) as part of the Keck Baryonic Structure Survey (KBSS). The KBSS-MOSFIRE sample is representative of star-forming galaxies at these redshifts, with stellar masses {M}* ={10}9{--}{10}11.5 {M}ȯ and star formation rates SFR = 3–1000 {M}ȯ yr‑1. We focus on robust measurements of many strong diagnostic emission lines for individual galaxies: [O ii]λλ3727, 3729, [Ne iii]λ3869, Hβ, [O iii]λ λ 4960, 5008, [N ii]λλ 6549, 6585, Hα, and [S ii]λλ6718, 6732. Comparisons with observations of typical local galaxies from the Sloan Digital Sky Survey and between subsamples of KBSS-MOSFIRE show that high-redshift galaxies exhibit a number of significant differences in addition to the well-known offset in log([O iii]λ 5008/Hβ) and log([N ii]λ 6585/Hα). We argue that the primary difference between H ii regions in z∼ 2.3 galaxies and those at z∼ 0 is an enhancement in the degree of nebular excitation, as measured by [O iii]/Hβ and {{R}}23\\equiv {log}[([O iii]λ λ 4960,5008+[O ii]λ λ 3727,3729)/Hβ]. At the same time, KBSS-MOSFIRE galaxies are ∼10 times more massive than z∼ 0 galaxies with similar ionizing spectra and have higher N/O (likely accompanied by higher O/H) at fixed excitation. These results indicate the presence of harder ionizing radiation fields at fixed N/O and O/H relative to typical z∼ 0 galaxies, consistent with Fe-poor stellar population models that include massive binaries, and highlight a population of massive, high-specific star formation rate galaxies at high redshift with systematically different star formation histories than galaxies of similar stellar mass today. The data presented in this paper were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of

  4. Nebular excitation in z ∼ 2 star-forming galaxies from the SINS and LUCI surveys: The influence of shocks and active galactic nuclei

    SciTech Connect

    Newman, Sarah F.; Genzel, Reinhard; Buschkamp, Peter; Förster Schreiber, Natascha M.; Kurk, Jaron; Rosario, David; Davies, Ric; Eisenhauer, Frank; Lutz, Dieter; Sternberg, Amiel; Gnat, Orly; Mancini, Chiara; Renzini, Alvio; Lilly, Simon J.; Carollo, C. Marcella; Burkert, Andreas; Cresci, Giovanni; Genel, Shy; Shapiro Griffin, Kristen; Hicks, Erin K. S.; and others

    2014-01-20

    Based on high-resolution, spatially resolved data of 10 z ∼ 2 star-forming galaxies from the SINS/zC-SINF survey and LUCI data for 12 additional galaxies, we probe the excitation properties of high-z galaxies and the impact of active galactic nuclei (AGNs), shocks, and photoionization. We explore how these spatially resolved line ratios can inform our interpretation of integrated emission line ratios obtained at high redshift. Many of our galaxies fall in the 'composite' region of the z ∼ 0 [N II]/Hα versus [O III]/Hβ diagnostic (BPT) diagram, between star-forming galaxies and those with AGNs. Based on our resolved measurements, we find that some of these galaxies likely host an AGN, while others appear to be affected by the presence of shocks possibly caused by an outflow or from an enhanced ionization parameter as compared with H II regions in normal, local star-forming galaxies. We find that the Mass-Excitation (MEx) diagnostic, which separates purely star-forming and AGN hosting local galaxies in the [O III]/Hβ versus stellar mass plane, does not properly separate z ∼ 2 galaxies classified according to the BPT diagram. However, if we shift the galaxies based on the offset between the local and z ∼ 2 mass-metallicity relation (i.e., to the mass they would have at z ∼ 0 with the same metallicity), we find better agreement between the MEx and BPT diagnostics. Finally, we find that metallicity calibrations based on [N II]/Hα are more biased by shocks and AGNs at high-z than the [O III]/Hβ/[N II]/Hα calibration.

  5. Extraction of distance restraints from pure shift NOE experiments.

    PubMed

    Kaltschnee, Lukas; Knoll, Kevin; Schmidts, Volker; Adams, Ralph W; Nilsson, Mathias; Morris, Gareth A; Thiele, Christina M

    2016-10-01

    NMR techniques incorporating pure shift methods to improve signal resolution have recently attracted much attention, owing to their potential use in studies of increasingly complex molecular systems. Extraction of frequencies from these simplified spectra enables easier structure determination, but only a few of the methods presented provide structural parameters derived from signal integral measurements. In particular, for quantification of the nuclear Overhauser effect (NOE) it is highly desirable to utilize pure shift techniques where signal overlap normally prevents accurate signal integration, to enable measurement of a larger number of interatomic distances. However, robust methods for the measurement of interatomic distances using the recently developed pure shift techniques have not been reported to date. In this work we discuss some of the factors determining the accuracy of measurements of signal integrals in interferogram-based Zangger-Sterk (ZS) pure shift NMR experiments. The ZS broadband homodecoupling technique is used in different experiments designed for quantitative NOE determination from pure shift spectra. It is shown that the techniques studied can be used for quantitative extraction of NOE-derived distance restraints, as exemplified for the test case of strychnine.

  6. Activating efficient phosphorescence from purely organic materials by crystal design.

    PubMed

    Bolton, Onas; Lee, Kangwon; Kim, Hyong-Jun; Lin, Kevin Y; Kim, Jinsang

    2011-03-01

    Phosphorescence is among the many functional features that, in practice, divide pure organic compounds from organometallics and inorganics. Considered to be practically non-phosphorescent, purely organic compounds (metal-free) are very rarely explored as emitters in phosphor applications, despite the emerging demand in this field. To defy this paradigm, we describe novel design principles to create purely organic materials demonstrating phosphorescence that can be turned on by incorporating halogen bonding into their crystals. By designing chromophores to contain triplet-producing aromatic aldehydes and triplet-promoting bromine, crystal-state halogen bonding can be made to direct the heavy atom effect to produce surprisingly efficient solid-state phosphorescence. When this chromophore is diluted into the crystal of a bi-halogenated, non-carbonyl analogue, ambient phosphorescent quantum yields reach 55%. Here, using this design, a series of pure organic phosphors are colour-tuned to emit blue, green, yellow and orange. From this initial discovery, a directed heavy atom design principle is demonstrated that will allow for the development of bright and practical purely organic phosphors.

  7. Extraction of distance restraints from pure shift NOE experiments

    NASA Astrophysics Data System (ADS)

    Kaltschnee, Lukas; Knoll, Kevin; Schmidts, Volker; Adams, Ralph W.; Nilsson, Mathias; Morris, Gareth A.; Thiele, Christina M.

    2016-10-01

    NMR techniques incorporating pure shift methods to improve signal resolution have recently attracted much attention, owing to their potential use in studies of increasingly complex molecular systems. Extraction of frequencies from these simplified spectra enables easier structure determination, but only a few of the methods presented provide structural parameters derived from signal integral measurements. In particular, for quantification of the nuclear Overhauser effect (NOE) it is highly desirable to utilize pure shift techniques where signal overlap normally prevents accurate signal integration, to enable measurement of a larger number of interatomic distances. However, robust methods for the measurement of interatomic distances using the recently developed pure shift techniques have not been reported to date. In this work we discuss some of the factors determining the accuracy of measurements of signal integrals in interferogram-based Zangger-Sterk (ZS) pure shift NMR experiments. The ZS broadband homodecoupling technique is used in different experiments designed for quantitative NOE determination from pure shift spectra. It is shown that the techniques studied can be used for quantitative extraction of NOE-derived distance restraints, as exemplified for the test case of strychnine.

  8. Investigation into the Advantages of Pure Perovskite Film without PbI2 for High Performance Solar Cell

    PubMed Central

    Kwon, Uisik; Hasan, Md Mehedi; Yin, Wenping; Kim, Dasom; Ha, Na Young; Lee, Soonil; Ahn, Tae Kyu; Park, Hui Joon

    2016-01-01

    In CH3NH3PbI3-based high efficiency perovskite solar cells (PSCs), tiny amount of PbI2 impurity was often found with the perovskite crystal. However, for two-step solution process-based perovskite films, most of findings have been based on the films having different morphologies between with and without PbI2. This was mainly due to the inferior morphology of pure perovskite film without PbI2, inevitably produced when the remaining PbI2 forced to be converted to perovskite, so advantages of pure perovskite photoactive layer without PbI2 impurity have been overlooked. In this work, we designed a printing-based two-step process, which could not only generate pure perovskite crystal without PbI2, but also provide uniform and full surface coverage perovskite film, of which nanoscale morphology was comparable to that prepared by conventional two-step solution process having residual PbI2. Our results showed that, in two-step solution process-based PSC, pure perovskite had better photon absorption and longer carrier lifetime, leading to superior photocurrent generation with higher power conversion efficiency. Furthermore, this process was further applicable to prepare mixed phase pure perovskite crystal without PbI2 impurity, and we showed that the additional merits such as extended absorption to longer wavelength, increased carrier lifetime and reduced carrier recombination could be secured. PMID:27786257

  9. Investigation into the Advantages of Pure Perovskite Film without PbI2 for High Performance Solar Cell.

    PubMed

    Kwon, Uisik; Hasan, Md Mehedi; Yin, Wenping; Kim, Dasom; Ha, Na Young; Lee, Soonil; Ahn, Tae Kyu; Park, Hui Joon

    2016-10-27

    In CH3NH3PbI3-based high efficiency perovskite solar cells (PSCs), tiny amount of PbI2 impurity was often found with the perovskite crystal. However, for two-step solution process-based perovskite films, most of findings have been based on the films having different morphologies between with and without PbI2. This was mainly due to the inferior morphology of pure perovskite film without PbI2, inevitably produced when the remaining PbI2 forced to be converted to perovskite, so advantages of pure perovskite photoactive layer without PbI2 impurity have been overlooked. In this work, we designed a printing-based two-step process, which could not only generate pure perovskite crystal without PbI2, but also provide uniform and full surface coverage perovskite film, of which nanoscale morphology was comparable to that prepared by conventional two-step solution process having residual PbI2. Our results showed that, in two-step solution process-based PSC, pure perovskite had better photon absorption and longer carrier lifetime, leading to superior photocurrent generation with higher power conversion efficiency. Furthermore, this process was further applicable to prepare mixed phase pure perovskite crystal without PbI2 impurity, and we showed that the additional merits such as extended absorption to longer wavelength, increased carrier lifetime and reduced carrier recombination could be secured.

  10. Investigation into the Advantages of Pure Perovskite Film without PbI2 for High Performance Solar Cell

    NASA Astrophysics Data System (ADS)

    Kwon, Uisik; Hasan, Md Mehedi; Yin, Wenping; Kim, Dasom; Ha, Na Young; Lee, Soonil; Ahn, Tae Kyu; Park, Hui Joon

    2016-10-01

    In CH3NH3PbI3-based high efficiency perovskite solar cells (PSCs), tiny amount of PbI2 impurity was often found with the perovskite crystal. However, for two-step solution process-based perovskite films, most of findings have been based on the films having different morphologies between with and without PbI2. This was mainly due to the inferior morphology of pure perovskite film without PbI2, inevitably produced when the remaining PbI2 forced to be converted to perovskite, so advantages of pure perovskite photoactive layer without PbI2 impurity have been overlooked. In this work, we designed a printing-based two-step process, which could not only generate pure perovskite crystal without PbI2, but also provide uniform and full surface coverage perovskite film, of which nanoscale morphology was comparable to that prepared by conventional two-step solution process having residual PbI2. Our results showed that, in two-step solution process-based PSC, pure perovskite had better photon absorption and longer carrier lifetime, leading to superior photocurrent generation with higher power conversion efficiency. Furthermore, this process was further applicable to prepare mixed phase pure perovskite crystal without PbI2 impurity, and we showed that the additional merits such as extended absorption to longer wavelength, increased carrier lifetime and reduced carrier recombination could be secured.

  11. Faithful Transfer Arbitrary Pure States with Mixed Resources

    NASA Astrophysics Data System (ADS)

    Luo, Ming-Xing; Li, Lin; Ma, Song-Ya; Chen, Xiu-Bo; Yang, Yi-Xian

    2013-09-01

    In this paper, we show that some special mixed quantum resource experience the same property of pure entanglement such as Bell state for quantum teleportation. It is shown that one mixed state and three bits of classical communication cost can be used to teleport one unknown qubit compared with two bits via pure resources. The schemes are easily implement with model physical techniques. Moreover, these resources are also optimal and typical for faithfully remotely prepare an arbitrary qubit, two-qubit and three-qubit states with mixed quantum resources. Our schemes are completed as same as those with pure quantum entanglement resources except only 1 bit additional classical communication cost required. The success probability is independent of the form of the mixed resources.

  12. Single biphoton ququarts as either pure or mixed states

    SciTech Connect

    Fedorov, M. V.; Volkov, P. A.; Mikhailova, J. M.

    2011-09-15

    We analyze features of mixed biphoton polarization states, which arise from pure states of polarization-frequency biphoton ququarts after averaging over frequencies of photons. For mixed states, we find their concurrence C, Schmidt parameter K, degree of polarization P, as well as the von Neumann mutual information I. In some simple cases, we also find the relative entropy S{sub rel} and the degree of classical correlations C{sub cl}. In mixed states, the Schmidt parameter does not characterize the degree of entanglement anymore, as it does in pure states. Nevertheless, the Schmidt parameter remains useful even in the case of mixed states because it remains directly related to the degree of polarization. We compare results occurring in the cases of full pure polarization-frequency states of ququarts and mixed states (averaged over frequencies). Differences between these results can be seen in experiments with and without frequency filters in front of a detector.

  13. The neuroanatomy of pure apraxia of speech in stroke.

    PubMed

    Graff-Radford, Jonathan; Jones, David T; Strand, Edythe A; Rabinstein, Alejandro A; Duffy, Joseph R; Josephs, Keith A

    2014-02-01

    The left insula or Broca's area have been proposed as the neuroanatomical correlate for apraxia of speech (AOS) based on studies of patients with both AOS and aphasia due to stroke. Studies of neurodegenerative AOS suggest the premotor area and the supplementary motor areas as the anatomical correlates. The study objective was to determine the common infarction area in patients with pure AOS due to stroke. Patients with AOS and no or equivocal aphasia due to ischemic stroke were identified through a pre-existing database. Seven subjects were identified. Five had pure AOS, and two had equivocal aphasia. MRI lesion analysis revealed maximal overlap spanning the left premotor and motor cortices. While both neurodegenerative AOS and stroke induced pure AOS involve the premotor cortex, further studies are needed to establish whether stroke-induced AOS and neurodegenerative AOS share a common anatomic substrate.

  14. The neuroanatomy of pure apraxia of speech in stroke

    PubMed Central

    Graff-Radford, Jonathan; Jones, David T.; Strand, Edythe A.; Rabinstein, Alejandro A.; Duffy, Joseph R.; Josephs, Keith A.

    2014-01-01

    The left insula or Broca’s area have been proposed as the neuroanatomical correlate for apraxia of speech (AOS) based on studies of patients with both AOS and aphasia due to stroke. Studies of neurodegenerative AOS suggest the premotor area and the supplementary motor areas as the anatomical correlates. The study objective was to determine the common infarction area in patients with pure AOS due to stroke. Patients with AOS and no or equivocal aphasia due to ischemic stroke were identified through a pre-existing database. Seven subjects were identified. Five had pure AOS, and two had equivocal aphasia. MRI lesion analysis revealed maximal overlap spanning the left premotor and motor cortices. While both neurodegenerative AOS and stroke induced pure AOS involve the premotor cortex, further studies are needed to establish whether stroke-induced AOS and neurodegenerative AOS share a common anatomic substrate. PMID:24556336

  15. Effect of vanadium carbide on commercial pure aluminum

    NASA Astrophysics Data System (ADS)

    Sun, Hua-ping; Wu, Jun; Tang, Tian; Fan, Bo; Tang, Zheng-hua

    2017-07-01

    The effect of vanadium carbide (VC) on the grain size of commercial pure aluminum was experimentally investigated by varying the content of VC, the holding time, and casting temperature. The refining efficiencies of VC and Al5Ti1B were also compared. The refined samples of commercial pure aluminum were examined using optical microscopy, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The results suggest that VC is a good refiner of commercial pure aluminum. The addition of only 0.3wt% VC can decrease the grain size of aluminum to 102 μm, whereas the casting temperature and holding time have little effect on the grain size. The refining efficiency of VC is better than that of Al5Ti1B. The VC particles in molten aluminum act as nuclei and the grain refinement of aluminum alloys by VC particles is achieved via heterogeneous nucleation.

  16. [Anesthetic management for a patient with pure autonomic failure].

    PubMed

    Kida, K; Mori, M; Yoshitake, S; Sendaya, K; Iwasaka, H; Taniguchi, K

    1997-06-01

    Pure autonomic failure is characterized by orthostatic hypotension, sweating disorder, urinary incontinence, and syncope. A 64 year-old man with pure autonomia failure was scheduled for suprapubic prostatectomy. We monitoring direct arterial pressure and inserted pulmonary artery catheter prior to the induction of anesthesia. General anesthesia was induced with diazepam 10 mg, fentanyl 0.3 mg, and vecuronium 8 mg for tracheal intubation. Anesthesia was maintained with sevoflurane (0.2-1.5%), 60% nitrous oxide in oxygen supplemented with intermittent epidural anesthesia. During anesthesia, blood loss was immediately replaced with banked blood because autonomic failure could not compensate hypovolemia well. Epidural anesthesia in this patient was considered to cause less hypotension than in patients with normal autonomic function. Therefore, we think epidural anesthesia is a useful anesthesia method for patients with pure autonomic failure. The emergence from anesthesia was smooth and no complications were seen during the perioperative period.

  17. Fine Needle Aspiration Cytology in Diagnosis of Pure Neuritic Leprosy

    PubMed Central

    Kumar, Bipin; Pradhan, Anju

    2011-01-01

    Leprosy is a chronic infection affecting mainly the skin and peripheral nerve. Pure neuritic form of this disease manifests by involvement of the nerve in the absence of skin lesions. Therefore, it can sometimes create a diagnostic problem. It often requires a nerve biopsy for diagnosis, which is an invasive procedure and may lead to neural deficit. Fine needle aspiration cytology (FNAC) of an affected nerve can be a valuable and less invasive procedure for the diagnosis of such cases. We report five suspected cases of pure neuritic Hansen's disease involving the common and superficial peroneal, ulnar, and median nerve, who underwent FNAC. Smears revealed nerve fibers infiltrated by chronic inflammatory cells in all cases, presence of epithelioid cells granulomas, and Langhans giant cells in three cases, and acid fast bacilli in two cases. In conclusion, FNAC is a safe, less invasive, and time saving procedure for the diagnosis of pure neuritic leprosy. PMID:21660285

  18. Excitation of coherent propagating spin waves by pure spin currents

    PubMed Central

    Demidov, Vladislav E.; Urazhdin, Sergei; Liu, Ronghua; Divinskiy, Boris; Telegin, Andrey; Demokritov, Sergej O.

    2016-01-01

    Utilization of pure spin currents not accompanied by the flow of electrical charge provides unprecedented opportunities for the emerging technologies based on the electron's spin degree of freedom, such as spintronics and magnonics. It was recently shown that pure spin currents can be used to excite coherent magnetization dynamics in magnetic nanostructures. However, because of the intrinsic nonlinear self-localization effects, magnetic auto-oscillations in the demonstrated devices were spatially confined, preventing their applications as sources of propagating spin waves in magnonic circuits using these waves as signal carriers. Here, we experimentally demonstrate efficient excitation and directional propagation of coherent spin waves generated by pure spin current. We show that this can be achieved by using the nonlocal spin injection mechanism, which enables flexible design of magnetic nanosystems and allows one to efficiently control their dynamic characteristics. PMID:26818232

  19. Fast word reading in pure alexia: "fast, yet serial".

    PubMed

    Bormann, Tobias; Wolfer, Sascha; Hachmann, Wibke; Neubauer, Claudia; Konieczny, Lars

    2015-01-01

    Pure alexia is a severe impairment of word reading in which individuals process letters serially with a pronounced length effect. Yet, there is considerable variation in the performance of alexic readers with generally very slow, but also occasionally fast responses, an observation addressed rarely in previous reports. It has been suggested that "fast" responses in pure alexia reflect residual parallel letter processing or that they may even be subserved by an independent reading system. Four experiments assessed fast and slow reading in a participant (DN) with pure alexia. Two behavioral experiments investigated frequency, neighborhood, and length effects in forced fast reading. Two further experiments measured eye movements when DN was forced to read quickly, or could respond faster because words were easier to process. Taken together, there was little support for the proposal that "qualitatively different" mechanisms or reading strategies underlie both types of responses in DN. Instead, fast responses are argued to be generated by the same serial-reading strategy.

  20. About the role of visual field defects in pure alexia.

    PubMed

    Pflugshaupt, Tobias; Gutbrod, Klemens; Wurtz, Pascal; von Wartburg, Roman; Nyffeler, Thomas; de Haan, Bianca; Karnath, Hans-Otto; Mueri, René M

    2009-07-01

    Pure alexia is an acquired reading disorder characterized by a disproportionate prolongation of reading time as a function of word length. Although the vast majority of cases reported in the literature show a right-sided visual defect, little is known about the contribution of this low-level visual impairment to their reading difficulties. The present study was aimed at investigating this issue by comparing eye movement patterns during text reading in six patients with pure alexia with those of six patients with hemianopic dyslexia showing similar right-sided visual field defects. We found that the role of the field defect in the reading difficulties of pure alexics was highly deficit-specific. While the amplitude of rightward saccades during text reading seems largely determined by the restricted visual field, other visuo-motor impairments-particularly the pronounced increases in fixation frequency and viewing time as a function of word length-may have little to do with their visual field defect. In addition, subtracting the lesions of the hemianopic dyslexics from those found in pure alexics revealed the largest group differences in posterior parts of the left fusiform gyrus, occipito-temporal sulcus and inferior temporal gyrus. These regions included the coordinate assigned to the centre of the visual word form area in healthy adults, which provides further evidence for a relation between pure alexia and a damaged visual word form area. Finally, we propose a list of three criteria that may improve the differential diagnosis of pure alexia and allow appropriate therapy recommendations.

  1. The friction behavior of semiconductors Si and GaAs in contact with pure metals

    NASA Technical Reports Server (NTRS)

    Mishina, H.

    1984-01-01

    The friction behavior of the semiconductors silicon and gallium arsenide in contact with pure metals was studied. Five transition and two nontransition metals, titanium, tantalum, nickel, palladium, platinum, copper, and silver, slid on a single crystal silicon (111) surface. Four metals, indium, nickel, copper and silver, slid on a single crystal gallium arsenide (100) surface. Experiments were conducted in room air and in a vacuum of 10 to the minus 7th power N/sq cm (10 to the minus 9th power torr). The results indicate that the sliding of silicon on the transition metals exhibits relatively higher friction than for the nontransition metals in contact with silicon. There is a clear correlation between friction and Schottky barrier height formed at the metal silicon interface for the transition metals. Transition metals with a higher barrier height on silicon had a lower friction. The same effect of barrier height was found for the friction of gallium arsenide in contact with metals.

  2. Pure double-layer bubbles in quadratic F (R ) gravity

    NASA Astrophysics Data System (ADS)

    Eiroa, Ernesto F.; Figueroa Aguirre, Griselda; Senovilla, José M. M.

    2017-06-01

    We present a class of spherically symmetric spacetimes corresponding to bubbles separating two regions with constant values of the scalar curvature, or equivalently with two different cosmological constants, in quadratic F (R ) theory. The bubbles are obtained by means of the junction formalism, and the matching hypersurface supports in general a thin shell and a gravitational double layer. In particular, we find that pure double layers are possible for appropriate values of the parameters of the model whenever the quadratic coefficient is negative. This is the first example of a pure double layer in a gravitational theory.

  3. Pure tone audiometry: comparison of general practice and hospital services

    PubMed Central

    Smith, Michael C.F.; Cable, Hugh R.; Wilmot, John F.

    1988-01-01

    Pure tone audiometry was obtained for both ears of 32 children by a general practitioner using a simple audiometer in his surgery, and by audiometricians in a hospital department on the same day. Comparing the worst hearing threshold at any of the three tested frequencies, the general practitioner did not find any ears to hear more than 10 dB better than the hospital (no false negatives). However, there were six false positives (9%) where the general practitioner identified an apparent hearing loss of greater than 15 dB. It is concluded that pure tone audiometry could be carried out accurately in the practice. PMID:3267745

  4. Clinical study of 222 patients with pure motor stroke

    PubMed Central

    Arboix, A; Padilla, I; Massons, J; Garcia-Eroles, L; Comes, E; Targa, C

    2001-01-01

    The objective was to assess the frequency of pure motor stroke caused by different stroke subtypes and to compare demographic, clinical, neuroimaging, and outcome data of pure motor stroke with those of patients with other lacunar stroke as well as with those of patients with non-lacunar stroke.
Data from 2000 patients with acute stroke (n=1761) or transient ischaemic attack (n=239) admitted consecutively to the department of neurology of an acute care 350 bed teaching hospital were prospectively collected in the Sagrat Cor Hospital of Barcelona stroke registry over a 10 year period. For the purpose of the study 222 (12.7%) patients with pure motor stroke were selected. The other study groups included 218 (12.3%) patients with other lacunar strokes and 1321 (75%) patients with non-lacunar stroke.
In relation to stroke subtype, lacunar infarcts were found in 189 (85%) patients, whereas ischaemic lacunar syndromes not due to lacunar infarcts occurred in 23 (10.4%) patients (atherothrombotic stroke in 12, cardioembolic stroke in seven, infarction of undetermined origin in three, and infarction of unusual aetiology in one) and haemorrhagic lacunar syndromes in 10 (4.5%). Patients with pure motor stroke showed a better outcome than patients with non-lacunar stroke with a significantly lower number of complications and in hospital mortality rate, shorter duration of hospital stay, and a higher number of symptom free patients at hospital discharge. After multivariate analysis, hypertension, diabetes, obesity, hyperlipidaemia, non-sudden stroke onset, internal capsule involvement, and pons topography seemed to be independent factors of pure motor stroke in patients with acute stroke.
In conclusion, about one of every 10 patients with acute stroke had a pure motor stroke. Pure motor stroke was caused by a lacunar infarct in 85% of patients and by other stroke subtypes in 15%. Several clinical features are more frequent in patients with pure motor stroke than in

  5. Localization of Vector Field on Pure Geometrical Thick Brane

    NASA Astrophysics Data System (ADS)

    Sui, Tao-Tao; Zhao, Li

    2017-06-01

    In this paper, we investigate the localization of a five-dimensional vector field on a pure geometrical thick brane. In previous work, it was shown that a free massless vector field cannot be localized on such thick brane. Hence we introduce the interaction between the vector field and the background scalar field. Two types of couplings are constructed as examples. We get a typical volcano potential for the first type of coupling and a finite square-well-like potential for the second one. Both of the two types of couplings ensure that the vector zero mode can be localized on the pure geometrical thick brane under some conditions.

  6. Spectroscopic characterization of pure and cation-stabilized sodium phosphate

    NASA Astrophysics Data System (ADS)

    Cole, R. S.; Frech, Roger

    2000-03-01

    A systematic study was conducted of pure Na3PO4 and solid solutions of Na3PO4 doped with Mg2+ and Zn2+. Na3PO4 has two solid phases: a low-temperature tetragonal phase and a high-temperature cubic phase. A factor group analysis of the two phases yielded the expected number of modes and their symmetry-based assignments. A temperature-dependent Raman spectroscopic study was then performed for the pure compound. Analysis of the doped Na3PO4 has also provided another description of the local structural distortions present in the cubic structure.

  7. Actuating dielectric elastomers in pure shear deformation by elastomeric conductors

    SciTech Connect

    Wang, Yin; Chen, Baohong; Zhou, Jinxiong; Bai, Yuanyuan; Wang, Hong

    2014-02-10

    Pure shear experiments are commonly used to characterize dielectric elastomer (DE) material properties and to evaluate DE actuator/generator performance. It is increasingly important for many applications to replace conventional carbon grease electrodes with stretchable elastomeric conductors. We formulate a theory for DE with elastomeric conductors, synthesize transparent hydrogel as ionic conductors, and measure actuation of DE in pure shear deformation. Maximum 67% actuation strain is demonstrated. The theory agrees well with our measurement and also correlates well with reported experiments on DE with electronic conductors.

  8. Spectrofluorimetric determination of famciclovir in pure and pharmaceutical preparations

    NASA Astrophysics Data System (ADS)

    Karasakal, A.; ULU, S. Tatar; Unal, D. Ozer

    2015-08-01

    A sensitive spectrofluorimetric method was developed for the determination of famciclovir in pure and pharmaceutical preparations. The method is based on the derivatization reaction of famciclovir with fluorescamine. The different experimental parameters that affect the fluorescence intensity were carefully studied, at once. The method was validated for linearity, limit of detection, limit of quantification, precision, accuracy, recovery, robustness. The assay was linear over the concentration range of 100 and 1000 ng/mL. The limits of detection and limit of quantification were calculated to be 51.13 and 153.39 ng/mL. The proposed method was applied to study of famciclovir in pure and in pharmaceutical preparations.

  9. Colorimetric Determination of Pure Mg2+-dependent Phosphatidate Phosphatase Activity

    PubMed Central

    Havriluk, Tara; Lozy, Fred; Siniossoglou, Symeon; Carman, George M.

    2008-01-01

    The malachite green-molybdate reagent was used for a colorimetric assay of pure Mg2+-dependent phosphatidate phosphatase activity. This enzyme plays a major role in fat metabolism. Enzyme activity was linear with time and protein concentration, and with the concentration of water-soluble dioctanoyl phosphatidate. The colorimetric assay was used to examine enzyme inhibition by phenylglyoxal, propranolol, and dimethyl sulfoxide. Pure enzyme and a water-soluble phosphatidate substrate were required for the assay, which should be applicable to a well-defined large-scale screen of Mg2+-dependent phosphatidate phosphatase inhibitors (or activators). PMID:17910939

  10. Hierarchy of Stochastic Pure States for Open Quantum System Dynamics

    NASA Astrophysics Data System (ADS)

    Suess, D.; Eisfeld, A.; Strunz, W. T.

    2014-10-01

    We derive a hierarchy of stochastic evolution equations for pure states (quantum trajectories) for open quantum system dynamics with non-Markovian structured environments. This hierarchy of pure states (HOPS) is generally applicable and provides the exact reduced density operator as an ensemble average over normalized states. The corresponding nonlinear equations are presented. We demonstrate that HOPS provides an efficient theoretical tool and apply it to the spin-boson model, the calculation of absorption spectra of molecular aggregates, and energy transfer in a photosynthetic pigment-protein complex.

  11. Quasimonoenergetic electron beams from laser wakefield acceleration in pure nitrogen

    SciTech Connect

    Mo, M. Z.; Ali, A.; Fedosejevs, R.; Fourmaux, S.; Lassonde, P.; Kieffer, J. C.

    2012-02-13

    Quasimonoenergetic electron beams with maximum energy >0.5 GeV and 2 mrad divergence have been generated in pure nitrogen gas via wakefield acceleration with 80 TW, 30 fs laser pulses. Long low energy tail features were typically observed due to continuous ionization injection. The measured peak electron energy decreased with the plasma density, agreeing with the predicted scaling for electrons. The experiments showed a threshold electron density of 3x10{sup 18}cm{sup -3} for self-trapping. Our experiments suggest that pure Nitrogen is a potential candidate gas to achieve GeV monoenergetic electrons using the ionization induced injection scheme for laser wakefield acceleration.

  12. Nebular Excitation in z ~ 2 Star-forming Galaxies from the SINS and LUCI Surveys: The Influence of Shocks and Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Newman, Sarah F.; Buschkamp, Peter; Genzel, Reinhard; Förster Schreiber, Natascha M.; Kurk, Jaron; Sternberg, Amiel; Gnat, Orly; Rosario, David; Mancini, Chiara; Lilly, Simon J.; Renzini, Alvio; Burkert, Andreas; Carollo, C. Marcella; Cresci, Giovanni; Davies, Ric; Eisenhauer, Frank; Genel, Shy; Shapiro Griffin, Kristen; Hicks, Erin K. S.; Lutz, Dieter; Naab, Thorsten; Peng, Yingjie; Tacconi, Linda J.; Wuyts, Stijn; Zamorani, Gianni; Vergani, Daniela; Weiner, Benjamin J.

    2014-01-01

    Based on high-resolution, spatially resolved data of 10 z ~ 2 star-forming galaxies from the SINS/zC-SINF survey and LUCI data for 12 additional galaxies, we probe the excitation properties of high-z galaxies and the impact of active galactic nuclei (AGNs), shocks, and photoionization. We explore how these spatially resolved line ratios can inform our interpretation of integrated emission line ratios obtained at high redshift. Many of our galaxies fall in the "composite" region of the z ~ 0 [N II]/Hα versus [O III]/Hβ diagnostic (BPT) diagram, between star-forming galaxies and those with AGNs. Based on our resolved measurements, we find that some of these galaxies likely host an AGN, while others appear to be affected by the presence of shocks possibly caused by an outflow or from an enhanced ionization parameter as compared with H II regions in normal, local star-forming galaxies. We find that the Mass-Excitation (MEx) diagnostic, which separates purely star-forming and AGN hosting local galaxies in the [O III]/Hβ versus stellar mass plane, does not properly separate z ~ 2 galaxies classified according to the BPT diagram. However, if we shift the galaxies based on the offset between the local and z ~ 2 mass-metallicity relation (i.e., to the mass they would have at z ~ 0 with the same metallicity), we find better agreement between the MEx and BPT diagnostics. Finally, we find that metallicity calibrations based on [N II]/Hα are more biased by shocks and AGNs at high-z than the [O III]/Hβ/[N II]/Hα calibration. Based on observations at the Very Large Telescope (VLT) of the European Southern Observatory (ESO), Paranal, Chile (ESO program IDs 073.B-9018, 076.A-0527, 079.A-0341, 080.A-0330, 080.A-0339, 080.A-0635, 083.A-0781,084.A-0853, 087.A-0081, 091.A.-0126) and at the Large Binocular Telescope (LBT) on Mt. Graham in Arizona.

  13. THE IRON PROJECT & THE RMAX PROJECT: Highly excited Core resonances in photoionzation of Fe XVII and impact on plasma opacities, oscillator strengths of Fe XIV, and nebular abundance of O II

    NASA Astrophysics Data System (ADS)

    Pradhan, Anil; Nahar, Sultana; Palay, Ethan; Eissner, Werner

    2011-05-01

    The aims of the Iron Project and the Rmax Project are detailed study of radiative and collisional processes of astrophysically abundant atoms and ions, mainly iron and iron-peak elements, over a wide energy range, from infra-red to X-rays. We will illustrate the dominance of high energy photoexciation-of-core (PEC) resonances in photoionization of Fe XVII due to strong coupling effects on dipole transition arrays 2p5 --> 2p4 (3 s , 3 d) in the core and examine PEC and non-PEC resonance strengths for their expanded role to incorporate inner-shell excitations for improved opacities. Comparisons show that the currently available cross sections from the Opacity Project are considerably underestimated. For Fe XIV, we present preliminary results from a large scale computation where 747 fine structure levels with n <= 10, l <= 9, and 0.5 <= J <= 9.5, and 71,407 electric dipole allowed fine structure transitions have been obtained. We will also demonstrate the fine structure effects on the collision strengths and in very low energy photoionzation for in nebular oxygen abundance. Partial Supports: NSF, DOE

  14. Similarities and differences between learning abilities, "pure" learning disabilities, "pure" ADHD and comorbid ADHD with learning disabilities.

    PubMed

    Mangina, Constantine A; Beuzeron-Mangina, Helen

    2009-08-01

    This research pursues the crucial question of the differentiation of preadolescents with "Pure" ADHD, comorbid ADHD with learning disabilities, "Pure" learning disabilities and age-matched normal controls. For this purpose, Topographic Mapping of Event-Related Brain Potentials (ERPs) to a Memory Workload Paradigm with visually presented words, Bilateral Electrodermal Activity during cognitive workload and Mangina-Test performance were used. The analysis of Topographic distribution of amplitudes revealed that normal preadolescents were significantly different from "Pure" ADHD (P<0.0001), "Pure" learning disabilities (P<0.0001), and comorbid ADHD with learning disabilities (P<0.0009), by displaying enhanced prefrontal and frontal negativities (N450). In contrast, preadolescents with "Pure" ADHD and comorbid ADHD with learning disabilities have shown a marked reduction of prefrontal and frontal negativities (N450). As for the "Pure" Learning Disabled preadolescents, very small positivities (P450) in prefrontal and frontal regions were obtained as compared to the other pathological groups. Bilateral Electrodermal Activity during cognitive workload revealed a significant main effect for groups (P<0.00001), Left versus Right (P=0.0029) and sessions (P=0.0136). A significant main effect for the Mangina-Test performance which separated the four groups was found (P<0.000001). Overall, these data support the existence of clear differences and similarities between the pathological preadolescent groups as opposed to age-matched normal controls. The psychophysiological differentiation of these groups, provides distinct biological markers which integrate central, autonomic and neuropsychometric variables by targeting the key features of these pathologies for diagnosis and intervention strategies and by providing knowledge for the understanding of normal neurocognitive processes and functions.

  15. Pure E and B polarization maps via Wiener filtering

    NASA Astrophysics Data System (ADS)

    Bunn, Emory F.; Wandelt, Benjamin

    2017-08-01

    In order to draw scientific conclusions from observations of cosmic microwave background (CMB) polarization, it is necessary to separate the contributions of the E and B components of the data. For data with incomplete sky coverage, there are ambiguous modes, which can be sourced by either E or B signals. Techniques exist for producing "pure" E and B maps, which are guaranteed to be free of cross-contamination, although the standard method, which involves constructing an eigenbasis, has a high computational cost. We show that such pure maps can be thought of as resulting from the application of a Wiener filter to the data. This perspective leads to far more efficient methods of producing pure maps. Moreover, by expressing the idea of purification in the general framework of Wiener filtering (i.e., maximization of a posterior probability), it leads to a variety of generalizations of the notion of pure E and B maps, e.g., accounting for noise or other contaminants in the data as well as correlations with temperature anisotropy.

  16. A Graphical Representation for the Fugacity of a Pure Substance

    ERIC Educational Resources Information Center

    Book, Neil L.; Sitton, Oliver C.

    2010-01-01

    The thermodynamic equations used to define and compute the fugacity of a pure substance are depicted as processes on a semi-logarithmic plot of pressure vs. molar Gibbs energy (PG diagram) with isotherms for the substance behaving as an ideal gas superimposed. The PG diagram clearly demonstrates the physical basis for the definitions and the…

  17. About the Role of Visual Field Defects in Pure Alexia

    ERIC Educational Resources Information Center

    Pflugshaupt, Tobias; Gutbrod, Klemens; Wurtz, Pascal; von Wartburg, Roman; Nyffeler, Thomas; de Haan, Bianca; Karnath, Hans-Otto; Mueri, Rene M.

    2009-01-01

    Pure alexia is an acquired reading disorder characterized by a disproportionate prolongation of reading time as a function of word length. Although the vast majority of cases reported in the literature show a right-sided visual defect, little is known about the contribution of this low-level visual impairment to their reading difficulties. The…

  18. Idealization in Chemistry: Pure Substance and Laboratory Product

    ERIC Educational Resources Information Center

    Fernández-González, Manuel

    2013-01-01

    This article analyzes the concept of idealization in chemistry and the role played by pure substance and laboratory product. This topic has evident repercussions in the educational contexts that are applied to the science classroom, which are highlighted throughout the text. A common structure for knowledge construction is proposed for both…

  19. Number Reading in Pure Alexia--A Review

    ERIC Educational Resources Information Center

    Starrfelt, Randi; Behrmann, Marlene

    2011-01-01

    It is commonly assumed that number reading can be intact in patients with pure alexia, and that this dissociation between letter/word recognition and number reading strongly constrains theories of visual word processing. A truly selective deficit in letter/word processing would strongly support the hypothesis that there is a specialized system or…

  20. A pure-sampling quantum Monte Carlo algorithm

    SciTech Connect

    Ospadov, Egor; Rothstein, Stuart M.

    2015-01-14

    The objective of pure-sampling quantum Monte Carlo is to calculate physical properties that are independent of the importance sampling function being employed in the calculation, save for the mismatch of its nodal hypersurface with that of the exact wave function. To achieve this objective, we report a pure-sampling algorithm that combines features of forward walking methods of pure-sampling and reptation quantum Monte Carlo (RQMC). The new algorithm accurately samples properties from the mixed and pure distributions simultaneously in runs performed at a single set of time-steps, over which extrapolation to zero time-step is performed. In a detailed comparison, we found RQMC to be less efficient. It requires different sets of time-steps to accurately determine the energy and other properties, such as the dipole moment. We implement our algorithm by systematically increasing an algorithmic parameter until the properties converge to statistically equivalent values. As a proof in principle, we calculated the fixed-node energy, static α polarizability, and other one-electron expectation values for the ground-states of LiH and water molecules. These quantities are free from importance sampling bias, population control bias, time-step bias, extrapolation-model bias, and the finite-field approximation. We found excellent agreement with the accepted values for the energy and a variety of other properties for those systems.

  1. Molarity (Aromic Density) of the Elements as Pure Crystals.

    ERIC Educational Resources Information Center

    Pauling, Linus; Herman, Zelek S.

    1985-01-01

    Provides background information for teachers on the atomic density of the elements as pure crystals. Atomic density is defined as the reciprocal of the atomic volume. Includes atomic-density diagrams which were prepared using the atomic-volume values given by Singman, supplemented by additional values for some allotropes. (JN)

  2. Pure Mediated Priming: A Retrospective Semantic Matching Model

    ERIC Educational Resources Information Center

    Jones, Lara L.

    2010-01-01

    Mediated priming refers to the activation of a target (e.g., "stripes") by a prime (e.g., "lion") that is related indirectly via a connecting mediator (e.g., tiger). In previous mediated priming studies (e.g., McNamara & Altarriba, 1988), the mediator was associatively related to the prime. In contrast, pure mediated…

  3. Information balance in quantum teleportation with an arbitrary pure state

    SciTech Connect

    Li Li; Chen Zengbing

    2005-07-15

    We study a general teleportation scheme with an arbitrary two-party pure state and derive a tight bound of the teleportation fidelity with a predesigned estimation of the unknown state to be teleported. This bound shows a piecewise balance between information gain and state disturbance. We also explain possible physical significance of the balance.

  4. In vitro degradation of pure Mg in response to glucose

    NASA Astrophysics Data System (ADS)

    Zeng, Rong-Chang; Li, Xiao-Ting; Li, Shuo-Qi; Zhang, Fen; Han, En-Hou

    2015-08-01

    Magnesium and its alloys are promising biodegradable biomaterials but are still challenging to be used in person with high levels of blood glucose or diabetes. To date, the influence of glucose on magnesium degradation has not yet been elucidated, this issue requires more attention. Herein, we present pure Mg exhibiting different corrosion responses to saline and Hank’s solutions with different glucose contents, and the degradation mechanism of pure Mg in the saline solution with glucose in comparison with mannitol as a control. On one hand, the corrosion rate of pure Mg increases with the glucose concentration in saline solutions. Glucose rapidly transforms into gluconic acid, which attacks the oxides of the metal and decreases the pH of the solution; it also promotes the absorption of chloride ions on the Mg surface and consequently accelerates corrosion. On the other hand, better corrosion resistance is obtained with increasing glucose content in Hank’s solution due to the fact that glucose coordinates Ca2+ ions in Hank’s solution and thus improves the formation of Ca-P compounds on the pure Mg surface. This finding will open up new avenues for research on the biodegradation of bio-Mg materials in general, which could yield many new and interesting results.

  5. Pure iron and other magnetic minerals in meteorites

    NASA Astrophysics Data System (ADS)

    Pechersky, D. M.; Markov, G. P.; Tsel'movich, V. A.

    2015-01-01

    The results of thermomagnetic and microprobe analyses of 37 samples from 25 different types of meteorite are analyzed with the focus on the presence of pure (nickel-free) iron in them. It is established that the metallic particles in the studied meteorites cluster in three isolated groups: (1) pure iron, (2) kamacite with mode 3-6% Ni, and (3) taenite with mode ˜50% Ni. The hiatuses in the Fe-Ni alloy compositions between these groups of magnetic grains contradict the Fe-Ni phase diagram, which predicts a continuous series of solid solutions in this system. This isolated distribution of the compositions of the metallic particles in the meteorites is reasonably accounted for by the specific properties of the melt (melts) and the processes of their crystallization and decomposition in space. It is suggested that pure iron in the meteorites could have been formed by either of two scenarios. According to the "primary," pure iron crystallizes from the melt, and according to the "secondary" scenario, it is produced by the decomposition of the solid solution.

  6. A Graphical Representation for the Fugacity of a Pure Substance

    ERIC Educational Resources Information Center

    Book, Neil L.; Sitton, Oliver C.

    2010-01-01

    The thermodynamic equations used to define and compute the fugacity of a pure substance are depicted as processes on a semi-logarithmic plot of pressure vs. molar Gibbs energy (PG diagram) with isotherms for the substance behaving as an ideal gas superimposed. The PG diagram clearly demonstrates the physical basis for the definitions and the…

  7. Simple reaction time for broadband sounds compared to pure tones.

    PubMed

    Schlittenlacher, Josef; Ellermeier, Wolfgang; Avci, Gül

    2017-02-01

    Although many studies have explored the relation between reaction time (RT) and loudness, including effects of intensity, frequency, and binaural summation, comparable work on spectral summation is rare. However, most real-world sounds are not pure tones and typically have bandwidths covering several critical bands. Since comparing to a 1-kHz pure tone, the reference tone, is important for loudness measurement and standardization, the present work focuses on comparing RTs for broadband noise to those for 1-kHz pure tones in three experiments using different spectral and binaural configurations. The results of Experiments 1 and 2 yield good quantitative agreement with spectral loudness summation models for moderate and high sound pressure levels, measured using both pink noise covering almost the entire hearing range and bandpass-filtered pink noise with different center frequencies. However, at lower levels, the RT measurements yield an interaction of level and bandwidth, which is not in line with loudness scaling data. In Experiment 3, which investigated the binaural summation of broadband sounds, the binaural gain for white noise was determined to be 9 dB, which is somewhat larger than what had been found in previous RT measurements using 1-kHz pure tones.

  8. In vitro degradation of pure Mg in response to glucose

    PubMed Central

    Zeng, Rong-Chang; Li, Xiao-Ting; Li, Shuo-Qi; Zhang, Fen; Han, En-Hou

    2015-01-01

    Magnesium and its alloys are promising biodegradable biomaterials but are still challenging to be used in person with high levels of blood glucose or diabetes. To date, the influence of glucose on magnesium degradation has not yet been elucidated, this issue requires more attention. Herein, we present pure Mg exhibiting different corrosion responses to saline and Hank’s solutions with different glucose contents, and the degradation mechanism of pure Mg in the saline solution with glucose in comparison with mannitol as a control. On one hand, the corrosion rate of pure Mg increases with the glucose concentration in saline solutions. Glucose rapidly transforms into gluconic acid, which attacks the oxides of the metal and decreases the pH of the solution; it also promotes the absorption of chloride ions on the Mg surface and consequently accelerates corrosion. On the other hand, better corrosion resistance is obtained with increasing glucose content in Hank’s solution due to the fact that glucose coordinates Ca2+ ions in Hank’s solution and thus improves the formation of Ca-P compounds on the pure Mg surface. This finding will open up new avenues for research on the biodegradation of bio-Mg materials in general, which could yield many new and interesting results. PMID:26264413

  9. Optimal dense coding with arbitrary pure entangled states

    SciTech Connect

    Feng, Yuan; Duan, Runyao; Ji, Zhengfeng

    2006-07-15

    We examine dense coding with an arbitrary pure entangled state sharing between the sender and the receiver. Upper bounds on the average success probability in approximate dense coding and on the probability of conclusive results in unambiguous dense coding are derived. We also construct the optimal protocol which saturates the upper bound in each case.

  10. Effect of dissociation on thermodynamic properties of pure diatomic gases

    NASA Technical Reports Server (NTRS)

    Woolley, Harold W

    1955-01-01

    A graphical method is described by which the enthalpy, entropy, and compressibility factor for the equilibrium mixture of atoms and diatomic molecules for pure gaseous elements may be obtained and shown for any dissociating element for which the necessary data exist. Results are given for hydrogen, oxygen, and nitrogen. The effect of dissociation on the heat capacity is discussed briefly.

  11. Molarity (Aromic Density) of the Elements as Pure Crystals.

    ERIC Educational Resources Information Center

    Pauling, Linus; Herman, Zelek S.

    1985-01-01

    Provides background information for teachers on the atomic density of the elements as pure crystals. Atomic density is defined as the reciprocal of the atomic volume. Includes atomic-density diagrams which were prepared using the atomic-volume values given by Singman, supplemented by additional values for some allotropes. (JN)

  12. Computer Pure-Tone and Operator Stress: Report III.

    ERIC Educational Resources Information Center

    Dow, Caroline; Covert, Douglas C.

    Pure-tone sound at 15,750 Herz generated by flyback transformers in many computer and video display terminal (VDT) monitors has stress-related productivity effects in some operators, especially women. College-age women in a controlled experiment simulating half a normal work day showed responses within the first half hour of exposure to a tone…

  13. Pure esophageal atresia with normal outer appearance: case report.

    PubMed

    Sanal, Murat; Haeussler, Beatrice; Tabarelli, Walther; Maurer, Kathrin; Sergi, Consolato; Hager, Josef

    2007-08-01

    Isolated esophageal atresia is characterized by a long segment between the 2 esophageal pouches. This article presents a case of pure esophageal atresia with a 1-cm-long segment at the midportion without discontinuity that resembled the subtype II3 according to the Kluth atlas. Resection of the atretic segment and primary anastomosis were performed successfully.

  14. Scintillation properties of pure CaF 2

    NASA Astrophysics Data System (ADS)

    Mikhailik, V. B.; Kraus, H.; Imber, J.; Wahl, D.

    2006-10-01

    The temperature dependence of the decay time and scintillation light yield of pure CaF 2 crystal was measured over the temperature range 8-305 K using the multiphoton coincidence counting technique. Pure CaF 2 exhibits emission of triplet self-trapped excitons at 280 nm with a slow decay, the time constant of which changes significantly with temperature. The main decay time constant increases by three orders of magnitude when cooled, from 0.96±0.06 μs at 295 K to 930±40 μs at 8 K. The results obtained demonstrate that the scintillation light yield of pure CaF 2 increases with decreasing temperature down to 20 K below which it is roughly constant. At low temperatures the light yield of CaF 2 is estimated to be 60% relative to that of pure CaWO 4. It is concluded that undoped calcium fluoride is a very attractive target material for experimental searches for rare events based on the detection of phonon and scintillation signals.

  15. Hyponatremia due to hypothyroidism: a pure renal mechanism.

    PubMed

    Schmitz, P H; de Meijer, P H; Meinders, A E

    2001-03-01

    Hyponatremia is a common disorder. When hyponatremia is the result of hypothyroidism it can be successfully treated with thyroid hormone substitution. We followed cumulative sodium- and fluid balances of a patient with hyponatremia, resulting from hypothyroidism. We concluded that hyponatremia in hypothyroidism is due to a pure renal mechanism, and cannot be ascribed to inappropriate secretion of antidiuretic hormone.

  16. Computer Pure-Tone and Operator Stress: Report III.

    ERIC Educational Resources Information Center

    Dow, Caroline; Covert, Douglas C.

    Pure-tone sound at 15,750 Herz generated by flyback transformers in many computer and video display terminal (VDT) monitors has stress-related productivity effects in some operators, especially women. College-age women in a controlled experiment simulating half a normal work day showed responses within the first half hour of exposure to a tone…

  17. Number Reading in Pure Alexia--A Review

    ERIC Educational Resources Information Center

    Starrfelt, Randi; Behrmann, Marlene

    2011-01-01

    It is commonly assumed that number reading can be intact in patients with pure alexia, and that this dissociation between letter/word recognition and number reading strongly constrains theories of visual word processing. A truly selective deficit in letter/word processing would strongly support the hypothesis that there is a specialized system or…

  18. A pure-sampling quantum Monte Carlo algorithm

    NASA Astrophysics Data System (ADS)

    Ospadov, Egor; Rothstein, Stuart M.

    2015-01-01

    The objective of pure-sampling quantum Monte Carlo is to calculate physical properties that are independent of the importance sampling function being employed in the calculation, save for the mismatch of its nodal hypersurface with that of the exact wave function. To achieve this objective, we report a pure-sampling algorithm that combines features of forward walking methods of pure-sampling and reptation quantum Monte Carlo (RQMC). The new algorithm accurately samples properties from the mixed and pure distributions simultaneously in runs performed at a single set of time-steps, over which extrapolation to zero time-step is performed. In a detailed comparison, we found RQMC to be less efficient. It requires different sets of time-steps to accurately determine the energy and other properties, such as the dipole moment. We implement our algorithm by systematically increasing an algorithmic parameter until the properties converge to statistically equivalent values. As a proof in principle, we calculated the fixed-node energy, static α polarizability, and other one-electron expectation values for the ground-states of LiH and water molecules. These quantities are free from importance sampling bias, population control bias, time-step bias, extrapolation-model bias, and the finite-field approximation. We found excellent agreement with the accepted values for the energy and a variety of other properties for those systems.

  19. Extracting pure endmembers using symmetric sparse representation for hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Sun, Weiwei; Liu, Chun; Sun, Yanwei; Li, Weiyue; Li, Jialin

    2016-10-01

    This article proposes a symmetric sparse representation (SSR) method to extract pure endmembers from hyperspectral imagery (HSI). The SSR combines the features of the linear unmixing model and the sparse subspace clustering model of endmembers, and it assumes that the desired endmembers and all the HSI pixel points can be sparsely represented by each other. It formulates the endmember extraction problem into a famous program of archetypal analysis, and accordingly, extracting pure endmembers can be transformed as finding the archetypes in the minimal convex hull containing all the HSI pixel points. The vector quantization scheme is adopted to help in carefully choosing the initial pure endmembers, and the archetypal analysis program is solved using the simple projected gradient algorithm. Seven state-of-the-art methods are implemented to make comparisons with the SSR on both synthetic and real hyperspectral images. Experimental results show that the SSR outperforms all the seven methods in spectral angle distance and root-mean-square error, and it can be a good alternative choice for extracting pure endmembers from HSI data.

  20. Local symmetry properties of pure three-qubit states

    NASA Astrophysics Data System (ADS)

    Carteret, H. A.; Sudbery, A.

    2000-07-01

    Entanglement types of pure states of three spin-½ particles are classified by means of their stabilizers in the group of local unitary transformations. It is shown that the stabilizer is generically discrete, and that a larger stabilizer indicates a stationary value for some local invariant. We describe all the exceptional states with enlarged stabilizers.

  1. A hybrid sensing approach for pure and adulterated honey classification.

    PubMed

    Subari, Norazian; Mohamad Saleh, Junita; Md Shakaff, Ali Yeon; Zakaria, Ammar

    2012-10-17

    This paper presents a comparison between data from single modality and fusion methods to classify Tualang honey as pure or adulterated using Linear Discriminant Analysis (LDA) and Principal Component Analysis (PCA) statistical classification approaches. Ten different brands of certified pure Tualang honey were obtained throughout peninsular Malaysia and Sumatera, Indonesia. Various concentrations of two types of sugar solution (beet and cane sugar) were used in this investigation to create honey samples of 20%, 40%, 60% and 80% adulteration concentrations. Honey data extracted from an electronic nose (e-nose) and Fourier Transform Infrared Spectroscopy (FTIR) were gathered, analyzed and compared based on fusion methods. Visual observation of classification plots revealed that the PCA approach able to distinct pure and adulterated honey samples better than the LDA technique. Overall, the validated classification results based on FTIR data (88.0%) gave higher classification accuracy than e-nose data (76.5%) using the LDA technique. Honey classification based on normalized low-level and intermediate-level FTIR and e-nose fusion data scored classification accuracies of 92.2% and 88.7%, respectively using the Stepwise LDA method. The results suggested that pure and adulterated honey samples were better classified using FTIR and e-nose fusion data than single modality data.

  2. Pure culture response of ectomycorrhizal fungi to imposed water stress

    Treesearch

    Mark D. Coleman; Caroline S. Bledsoe; William Lopushinsky

    1989-01-01

    The ability of ectomycorrhizal fungal isolates to tolerate imposed water stress in pure culture was examined in 55 isolates of 18 species. Water potential treatments, adjusted with polyethylene glycol, were applied to Petri dish units. These units allowed colony diameter measurements of fungi grown on liquid media. Delayed growth initiation and inhibition of growth...

  3. A pure-sampling quantum Monte Carlo algorithm.

    PubMed

    Ospadov, Egor; Rothstein, Stuart M

    2015-01-14

    The objective of pure-sampling quantum Monte Carlo is to calculate physical properties that are independent of the importance sampling function being employed in the calculation, save for the mismatch of its nodal hypersurface with that of the exact wave function. To achieve this objective, we report a pure-sampling algorithm that combines features of forward walking methods of pure-sampling and reptation quantum Monte Carlo (RQMC). The new algorithm accurately samples properties from the mixed and pure distributions simultaneously in runs performed at a single set of time-steps, over which extrapolation to zero time-step is performed. In a detailed comparison, we found RQMC to be less efficient. It requires different sets of time-steps to accurately determine the energy and other properties, such as the dipole moment. We implement our algorithm by systematically increasing an algorithmic parameter until the properties converge to statistically equivalent values. As a proof in principle, we calculated the fixed-node energy, static α polarizability, and other one-electron expectation values for the ground-states of LiH and water molecules. These quantities are free from importance sampling bias, population control bias, time-step bias, extrapolation-model bias, and the finite-field approximation. We found excellent agreement with the accepted values for the energy and a variety of other properties for those systems.

  4. Pure Mediated Priming: A Retrospective Semantic Matching Model

    ERIC Educational Resources Information Center

    Jones, Lara L.

    2010-01-01

    Mediated priming refers to the activation of a target (e.g., "stripes") by a prime (e.g., "lion") that is related indirectly via a connecting mediator (e.g., tiger). In previous mediated priming studies (e.g., McNamara & Altarriba, 1988), the mediator was associatively related to the prime. In contrast, pure mediated…

  5. Rare or unusual causes of chronic, isolated, pure aortic regurgitation

    SciTech Connect

    Waller, B.F.; Taliercio, C.P.; Dickos, D.K.; Howard, J.; Adlam, J.H.; Jolly, W. )

    1990-08-01

    Six patients undergoing aortic valve replacement had rare or unusual causes of isolated, pure aortic regurgitation. Two patients had congenitally bicuspid aortic valves with a false commissure (raphe) displaced to the aortic wall (tethered bicuspid aortic valve), two had floppy aortic valves, one had a congenital quadricuspid valve, and one had radiation-induced valve damage.

  6. About the Role of Visual Field Defects in Pure Alexia

    ERIC Educational Resources Information Center

    Pflugshaupt, Tobias; Gutbrod, Klemens; Wurtz, Pascal; von Wartburg, Roman; Nyffeler, Thomas; de Haan, Bianca; Karnath, Hans-Otto; Mueri, Rene M.

    2009-01-01

    Pure alexia is an acquired reading disorder characterized by a disproportionate prolongation of reading time as a function of word length. Although the vast majority of cases reported in the literature show a right-sided visual defect, little is known about the contribution of this low-level visual impairment to their reading difficulties. The…

  7. Generalized Pure Density Matrices and the Standard Model

    NASA Astrophysics Data System (ADS)

    Brannen, Carl

    2015-04-01

    We consider generalizations of pure density matrices that have ρρ = ρ , but give up the trace=1 requirement. Given a representation of a quantum algebra in N × N complex matrices, the elements that satisfy ρρ = ρ can be taken to be pure density matrix states. In the Standard Model, particles from different ``superselection sectors'' cannot form linear superpositions. For example, it is impossible to form a linear superposition between an electron and a neutrino. We report that some quantum algebras give symmetry, particle and generation content, gauge freedom, and superselection sectors that are similar to those of the Standard Model. Our lecture will consider as an example the 4 × 4 complex matrices. There are 16 that are diagonal with ρρ = ρ . The 4 with trace=1 give the usual pure density matrices. We will show that the 6 with trace=2 form an SU(3) triplet of three superselection sectors, with each sector consisting of an SU(2) doublet. Considering one of these sectors, the mapping to SU(2) is not unique; there is an SU(2) gauge freedom. This gauge freedom is an analogy to the U(1) gauge freedom that arises when converting a pure density matrix to a state vector.

  8. Idealization in Chemistry: Pure Substance and Laboratory Product

    ERIC Educational Resources Information Center

    Fernández-González, Manuel

    2013-01-01

    This article analyzes the concept of idealization in chemistry and the role played by pure substance and laboratory product. This topic has evident repercussions in the educational contexts that are applied to the science classroom, which are highlighted throughout the text. A common structure for knowledge construction is proposed for both…

  9. A Hybrid Sensing Approach for Pure and Adulterated Honey Classification

    PubMed Central

    Subari, Norazian; Saleh, Junita Mohamad; Shakaff, Ali Yeon Md; Zakaria, Ammar

    2012-01-01

    This paper presents a comparison between data from single modality and fusion methods to classify Tualang honey as pure or adulterated using Linear Discriminant Analysis (LDA) and Principal Component Analysis (PCA) statistical classification approaches. Ten different brands of certified pure Tualang honey were obtained throughout peninsular Malaysia and Sumatera, Indonesia. Various concentrations of two types of sugar solution (beet and cane sugar) were used in this investigation to create honey samples of 20%, 40%, 60% and 80% adulteration concentrations. Honey data extracted from an electronic nose (e-nose) and Fourier Transform Infrared Spectroscopy (FTIR) were gathered, analyzed and compared based on fusion methods. Visual observation of classification plots revealed that the PCA approach able to distinct pure and adulterated honey samples better than the LDA technique. Overall, the validated classification results based on FTIR data (88.0%) gave higher classification accuracy than e-nose data (76.5%) using the LDA technique. Honey classification based on normalized low-level and intermediate-level FTIR and e-nose fusion data scored classification accuracies of 92.2% and 88.7%, respectively using the Stepwise LDA method. The results suggested that pure and adulterated honey samples were better classified using FTIR and e-nose fusion data than single modality data. PMID:23202033

  10. Entropy for quantum pure states and quantum H theorem

    NASA Astrophysics Data System (ADS)

    Han, Xizhi; Wu, Biao

    2015-06-01

    We construct a complete set of Wannier functions that are localized at both given positions and momenta. This allows us to introduce the quantum phase space, onto which a quantum pure state can be mapped unitarily. Using its probability distribution in quantum phase space, we define an entropy for a quantum pure state. We prove an inequality regarding the long-time behavior of our entropy's fluctuation. For a typical initial state, this inequality indicates that our entropy can relax dynamically to a maximized value and stay there most of time with small fluctuations. This result echoes the quantum H theorem proved by von Neumann [Zeitschrift für Physik 57, 30 (1929), 10.1007/BF01339852]. Our entropy is different from the standard von Neumann entropy, which is always zero for quantum pure states. According to our definition, a system always has bigger entropy than its subsystem even when the system is described by a pure state. As the construction of the Wannier basis can be implemented numerically, the dynamical evolution of our entropy is illustrated with an example.

  11. Pure dephasing of single Mn spin in semiconductor quantum dots

    NASA Astrophysics Data System (ADS)

    Liu, Dingyang; Lai, Wenxi; Yang, Wen

    2017-08-01

    We present comprehensive analytical and numerical studies on the pure dephasing of a single Mn spin in a semiconductor quantum dot due to (i) its sp-d exchange interaction with an electronic environment, and (ii) its hyperfine interaction with the nuclear spin environment. For (i), by modeling the electronic environment by an open two-level system, we provide exact analytical expressions and present detailed analysis for the Mn spin pure dephasing in both the Markovian and non-Markovian regimes. This provides a clear physical picture and a general theoretical framework based on which we estimate the Mn spin pure dephasing due to various fluctuations (such as thermal excitation, optical pumping, tunneling, or electron/hole spin relaxation) of the electronic environment and reveals a series of interesting behaviors, such as thermal, optical, and electrical control of the crossover between the Markov and non-Markov regimes. In particular, we find rapid Mn spin pure dephasing on a nanosecond time scale by the thermal fluctuation and optical pumping, but these mechanisms can be strongly suppressed by shifting the electron envelope function relative to the Mn atom with an external electric field through the quantum-confined Stark effect. The thermal fluctuation mechanism is also exponentially suppressed at low temperature. For (ii), we find that the Mn spin dephasing time is limited by the thermal fluctuation of the nuclear spins to a few microseconds even at low temperature and its value varies from sample to sample, depending on the distribution of spinful isotopes on the nearest-neighbor sites surrounding the substitutional Mn atom. Our findings may be useful to understand and suppress the Mn spin pure dephasing for its applications in quantum information processing.

  12. Pure drug nanoparticles in tablets: what are the dissolution limitations?

    NASA Astrophysics Data System (ADS)

    Heng, Desmond; Ogawa, Keiko; Cutler, David J.; Chan, Hak-Kim; Raper, Judy A.; Ye, Lin; Yun, Jimmy

    2010-06-01

    There has been increasing interests for drug companies to incorporate drug nanoparticles into their existing formulations. However, technical knowledge in this area is still in its infancy and more study needs to be done to stimulate growth in this fledging field. There is a need to scrutinize the performance of pure drug nanoparticles in tablets, particularly relating formulation variables to their dissolution performance. Application of the pure form, synthesized without the use of surfactants or stabilizers, is often preferred to maximize drug loading and also to minimize toxicity. Cefuroxime axetil, a poorly water-soluble cephalosporin antibiotic, was used as the model drug in the formulation development. Drug release rate, tablet disintegration time, tensile strength and energy of failure were predominantly influenced by the amount of super-disintegrant, amount of surfactant, compression force and diluent species, respectively. The compression rate had minimal impact on the responses. The main hurdle confronting the effective use of pure drug nanoparticles in tablets is the difficulty in controlling aggregation in solution, which could potentially be aggravated by the tabletting process. Through the use of elevated levels of surfactants (8 w/w% sodium dodecyl sulphate), drug release from the nanoparticle preparation was enhanced from 58.0 ± 2.7% to 72.3 ± 0.7% in 10 min. Hence, it is recommended that physical formulations for pure drug nanoparticles be focused on the particle de-aggregation step in solution, if much higher rates are to be desired. In conclusion, even though pure drug nanoparticles could be easily synthesized, limitations from aggregation may need to be overcome, before successful application in tablets can be fully realized.

  13. Microwave flow and conventional heating effects on the physicochemical properties, bioactive compounds and enzymatic activity of tomato puree.

    PubMed

    Arjmandi, Mitra; Otón, Mariano; Artés, Francisco; Artés-Hernández, Francisco; Gómez, Perla A; Aguayo, Encarna

    2017-02-01

    Thermal processing causes a number of undesirable changes in physicochemical and bioactive properties of tomato products. Microwave (MW) technology is an emergent thermal industrial process that offers a rapid and uniform heating, high energy efficiency and high overall quality of the final product. The main quality changes of tomato puree after pasteurization at 96 ± 2 °C for 35 s, provided by a semi-industrial continuous microwave oven (MWP) under different doses (low power/long time to high power/short time) or by conventional method (CP) were studied. All heat treatments reduced colour quality, total antioxidant capacity and vitamin C, with a greater reduction in CP than in MWP. On the other hand, use of an MWP, in particular high power/short time (1900 W/180 s, 2700 W/160 s and 3150 W/150 s) enhanced the viscosity and lycopene extraction and decreased the enzyme residual activity better than with CP samples. For tomato puree, polygalacturonase was the more thermo-resistant enzyme, and could be used as an indicator of pasteurization efficiency. MWP was an excellent pasteurization technique that provided tomato puree with improved nutritional quality, reducing process times compared to the standard pasteurization process. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  14. A Picture-perfect Pure-disc Galaxy

    NASA Astrophysics Data System (ADS)

    2011-02-01

    The bright galaxy NGC 3621, captured here using the Wide Field Imager on the 2.2-metre telescope at ESO's La Silla Observatory in Chile, appears to be a fine example of a classical spiral. But it is in fact rather unusual: it does not have a central bulge and is therefore described as a pure-disc galaxy. NGC 3621 is a spiral galaxy about 22 million light-years away in the constellation of Hydra (The Sea Snake). It is comparatively bright and can be seen well in moderate-sized telescopes. This picture was taken using the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile. The data were selected from the ESO archive by Joe DePasquale as part of the Hidden Treasures competition [1]. Joe's picture of NGC 3621 was ranked fifth in the competition. This galaxy has a flat pancake shape, indicating that it hasn't yet come face to face with another galaxy as such a galactic collision would have disturbed the thin disc of stars, creating a small bulge in its centre. Most astronomers think that galaxies grow by merging with other galaxies, in a process called hierarchical galaxy formation. Over time, this should create large bulges in the centres of spirals. Recent research, however, has suggested that bulgeless, or pure-disc, spiral galaxies like NGC 3621 are actually fairly common. This galaxy is of further interest to astronomers because its relative proximity allows them to study a wide range of astronomical objects within it, including stellar nurseries, dust clouds, and pulsating stars called Cepheid variables, which astronomers use as distance markers in the Universe [2]. In the late 1990s, NGC 3621 was one of 18 galaxies selected for a Key Project of the Hubble Space Telescope: to observe Cepheid variables and measure the rate of expansion of the Universe to a higher accuracy than had been possible before. In the successful project, 69 Cepheid variables were observed in this galaxy alone. Multiple monochrome images taken through

  15. Switching from pure- into simple-shear mode during uplift of the Altiplano plateau (Central Andes)

    NASA Astrophysics Data System (ADS)

    Babeyko, A. Yu.; Sobolev, S. V.

    2003-04-01

    The Altiplano plateau of the Central Andes is the second greatest plateau in the world after Tibet with an average elevation of about 4 km formed as a result of ocean-continent collision between subducting Nasca plate on the west and Brazilian shield on the east. According to the well known Isacks (1988) scenario, the Cenozoic evolution of the plateau started ca. 30 Ma in response to the retreat of the flat-subducted Nasca plate. Astenospheric material, which replaced the retreated plate, thermally thinned and softened the overlying lithosphere. The Altiplano crust, being pushed by the Brazilian shield from the east, was first shortened in a pure-shear mode and reached 60-70 km in thickness. At ca. 8-10 Ma deformation changed to a simple-shear mode: it was ceased in the upper crust of the plateau and migrated eastwards, into the Subandean, while the plateau itself continued to grow due to ongoing shortening in the lower crust. We employ numerical 2D thermomechanical modelling to test the above scenario and to evaluate the key parameters, which account for the transition from pure- to simple- shear style of the lithosphere-scale deformation under pure-shear boundary condition. As a numerical tool we use explicit finite difference/finite element lagrangian code with markers tracking material properties. The model contains rheologically different layers representing sediments, felsic and mafic crust, lithospheric mantle, and astenosphere. Rheological laws are Mohr-Coloumb elasto-plastic with softening and Maxwell visco-elastic with nonlinear power-law creep. Initial and boundary conditions simulate thermal activation of the Altiplano lithosphere by upwelling astenosphere as well as its westward pushing by the cold Brazilian shield with constant velocity. We found that model shortening always occurs in a pure-shear mode unless the uppermost crust of the Brazilian shield becomes during the deformation considerably weaker than the Altiplano upper crust (drop of friction

  16. Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp

    PubMed Central

    2014-01-01

    Over the last few decades, researchers have developed a number of empirical and theoretical models for the correlation and prediction of the thermophysical properties of pure fluids and mixtures treated as pseudo-pure fluids. In this paper, a survey of all the state-of-the-art formulations of thermophysical properties is presented. The most-accurate thermodynamic properties are obtained from multiparameter Helmholtz-energy-explicit-type formulations. For the transport properties, a wider range of methods has been employed, including the extended corresponding states method. All of the thermophysical property correlations described here have been implemented into CoolProp, an open-source thermophysical property library. This library is written in C++, with wrappers available for the majority of programming languages and platforms of technical interest. As of publication, 110 pure and pseudo-pure fluids are included in the library, as well as properties of 40 incompressible fluids and humid air. The source code for the CoolProp library is included as an electronic annex. PMID:24623957

  17. Pure odd-order oscillators with constant excitation

    NASA Astrophysics Data System (ADS)

    Cveticanin, L.

    2011-02-01

    In this paper the excited vibrations of a truly nonlinear oscillator are analyzed. The excitation is assumed to be constant and the nonlinearity is pure (without a linear term). The mathematical model is a second-order nonhomogeneous differential equation with strong nonlinear term. Using the first integral, the exact value of period of vibration i.e., angular frequency of oscillator described with a pure nonlinear differential equation with constant excitation is analytically obtained. The closed form solution has the form of gamma function. The period of vibration depends on the value of excitation and of the order and coefficient of the nonlinear term. For the case of pure odd-order-oscillators the approximate solution of differential equation is obtained in the form of trigonometric function. The solution is based on the exact value of period of vibration. For the case when additional small perturbation of the pure oscillator acts, the so called 'Cveticanin's averaging method' for a truly nonlinear oscillator is applied. Two special cases are considered: one, when the additional term is a function of distance, and the second, when damping acts. To prove the correctness of the method the obtained results are compared with those for the linear oscillator. Example of pure cubic oscillator with constant excitation and linear damping is widely discussed. Comparing the analytically obtained results with exact numerical ones it is concluded that they are in a good agreement. The investigations reported in the paper are of special interest for those who are dealing with the problem of vibration reduction in the oscillator with constant excitation and pure nonlinear restoring force the examples of which can be found in various scientific and engineering systems. For example, such mechanical systems are seats in vehicles, supports for machines, cutting machines with periodical motion of the cutting tools, presses, etc. The examples can be find in electronics

  18. NEBULAR ATTENUATION IN H{alpha}-SELECTED STAR-FORMING GALAXIES AT z = 0.8 FROM THE NewH{alpha} SURVEY

    SciTech Connect

    Momcheva, Ivelina G.; Lee, Janice C.; Ouchi, Masami; Ly, Chun; Salim, Samir; Dale, Daniel A.; Finn, Rose; Ono, Yoshiaki

    2013-02-01

    We present measurements of the dust attenuation of H{alpha}-selected emission-line galaxies at z = 0.8 from the NewH{alpha} narrowband survey. The analysis is based on deep follow-up spectroscopy with Magellan/IMACS, which captures the strong rest-frame optical emission lines from [O II] {lambda}3727 to [O III] {lambda}5007. The spectroscopic sample used in this analysis consists of 341 confirmed H{alpha} emitters. We place constraints on the active galactic nucleus (AGN) fraction using diagnostics that can be applied at intermediate redshift. We find that at least 5% of the objects in our spectroscopic sample can be classified as AGNs and 2% are composite, i.e., powered by a combination of star formation and AGN activity. We measure the dust attenuation for individual objects from the ratios of the higher order Balmer lines. The H{beta} and H{gamma} pair of lines is detected with S/N > 5 in 55 individual objects and the H{beta} and H{delta} pair is detected in 50 individual objects. We also create stacked spectra to probe the attenuation in objects without individual detections. The median attenuation at H{alpha} based on the objects with individually detected lines is A(H{alpha}) = 0.9 {+-} 1.0 mag, in good agreement with the attenuation found in local samples of star-forming galaxies. We find that the z = 0.8 galaxies occupy a similar locus of attenuation as a function of magnitude, mass, and star formation rate (SFR) as a comparison sample drawn from the SDSS DR4. Both the results from the individual z = 0.8 galaxies and from the stacked spectra show consistency with the mass-attenuation and SFR-attenuation relations found in the local universe, indicating that these relations are also applicable at intermediate redshift.

  19. 7 CFR 201.48 - Kind or variety considered pure seed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Kind or variety considered pure seed. 201.48 Section... variety considered pure seed. The pure seed shall include all seeds of each kind or each kind and variety... present to the extent of 5 percent or less of the whole may be considered pure seed if shown on the...

  20. 7 CFR 201.48 - Kind or variety considered pure seed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Kind or variety considered pure seed. 201.48 Section... variety considered pure seed. The pure seed shall include all seeds of each kind or each kind and variety... present to the extent of 5 percent or less of the whole may be considered pure seed if shown on the...

  1. 7 CFR 201.48 - Kind or variety considered pure seed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Kind or variety considered pure seed. 201.48 Section... variety considered pure seed. The pure seed shall include all seeds of each kind or each kind and variety... present to the extent of 5 percent or less of the whole may be considered pure seed if shown on the...

  2. 7 CFR 201.48 - Kind or variety considered pure seed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Kind or variety considered pure seed. 201.48 Section... variety considered pure seed. The pure seed shall include all seeds of each kind or each kind and variety... present to the extent of 5 percent or less of the whole may be considered pure seed if shown on the...

  3. Modeling pure culture heterotrophic production of polyhydroxybutyrate (PHB).

    PubMed

    Mozumder, Md Salatul Islam; Goormachtigh, Laurens; Garcia-Gonzalez, Linsey; De Wever, Heleen; Volcke, Eveline I P

    2014-03-01

    In this contribution a mechanistic model describing the production of polyhydroxybutyrate (PHB) through pure-culture fermentation was developed, calibrated and validated for two different substrates, namely glucose and waste glycerol. In both cases, non-growth-associated PHB production was triggered by applying nitrogen limitation. The occurrence of some growth-associated PHB production besides non-growth-associated PHB production was demonstrated, although it is inhibited in the presence of nitrogen. Other phenomena observed experimentally and described by the model included biomass growth on PHB and non-linear product inhibition of PHB production. The accumulated impurities from the waste substrate negatively affected the obtained maximum PHB content. Overall, the developed mathematical model provided an accurate prediction of the dynamic behavior of heterotrophic biomass growth and PHB production in a two-phase pure culture system.

  4. Synthesis and photoluminescence of ultra-pure germanium nanoparticles

    NASA Astrophysics Data System (ADS)

    Chivas, R.; Yerci, S.; Li, R.; Dal Negro, L.; Morse, T. F.

    2011-09-01

    We have used aerosol deposition to synthesize defect and micro-strain free, ultra-pure germanium nanoparticles. Transmission electron microscopy images show a core-shell configuration with highly crystalline core material. Powder X-ray diffraction measurements verify the presence of highly pure, nano-scale germanium with average crystallite size of 30 nm and micro-strain of 0.058%. X-ray photoelectron spectroscopy demonstrates that GeO x ( x ⩽ 2) shells cover the surfaces of the nanoparticles. Under optical excitation, these nanoparticles exhibit two separate emission bands at room temperature: a visible emission at 500 nm with 0.5-1 ns decay times and an intense near-infrared emission at 1575 nm with up to ˜20 μs lifetime.

  5. Five Measurement Bases Determine Pure Quantum States on Any Dimension.

    PubMed

    Goyeneche, D; Cañas, G; Etcheverry, S; Gómez, E S; Xavier, G B; Lima, G; Delgado, A

    2015-08-28

    A long-standing problem in quantum mechanics is the minimum number of observables required for the characterization of unknown pure quantum states. The solution to this problem is especially important for the developing field of high-dimensional quantum information processing. In this work we demonstrate that any pure d-dimensional state is unambiguously reconstructed by measuring five observables, that is, via projective measurements onto the states of five orthonormal bases. Thus, in our method the total number of different measurement outcomes (5d) scales linearly with d. The state reconstruction is robust against experimental errors and requires simple postprocessing, regardless of d. We experimentally demonstrate the feasibility of our scheme through the reconstruction of eight-dimensional quantum states, encoded in the momentum of single photons.

  6. The formation of blobs from a pure interchange process

    SciTech Connect

    Zhu, P.; Sovinec, C. R.; Hegna, C. C.

    2015-02-15

    In this work, we focus on examining a pure interchange process in a shear-less slab configuration as a prototype mechanism for blob formation. We employ full magnetohydrodynamic simulations to demonstrate that the blob-like structures can emerge through the nonlinear development of a pure interchange instability originating from a pedestal-like transition region. In the early nonlinear stage, filamentary structures develop and extend in the direction of the effective gravity. The blob-like structures appear when the radially extending filaments break off and disconnect from the core plasma. The morphology and the dynamics of these filaments and blobs vary dramatically with a sensitive dependence on the dissipation mechanisms in the system and the initial perturbation. Despite the complexity in morphology and dynamics, the nature of the entire blob formation process in the shear-less slab configuration remains strictly interchange without involving any change in magnetic topology.

  7. Pure valley and spin polarization current in ferromagnetic graphene junction

    NASA Astrophysics Data System (ADS)

    Wu, Qing-Ping; Liu, Zheng-Fang; Chen, Ai-Xi; Xiao, Xian-Bo; Miao, Guo-Xing

    2017-02-01

    We investigate the band structure and spin- and valley-dependent transport in ferromagnetic graphene double junctions using the transfer matrix method. The ferromagnetic double junctions include a lateral layout of normal/magnetic vector potential/normal/effective exchange field/normal graphene regions. We find that the strain combined with magnetic vector potentials breaks the valley degeneracy, and the strain combined with the effective exchange field breaks the spin degeneracy, so that there exists a spin- and valley-dependent gap in the ferromagnetic graphene double junctions, which allows only one spin species with special valley characteristics to be transported. Thus, this type of junction can achieve simultaneously pure spin- and pure valley-polarized currents and function as a perfect valley filter and a perfect spin filter. The exact nature of the valley filtering and spin filtering can be tuned by the strain, magnetic barrier, and effective exchange field strength.

  8. Direct Observation of High Photoresponsivity in Pure Graphene Photodetectors

    NASA Astrophysics Data System (ADS)

    Liu, Yanping; Xia, Qinglin; He, Jun; Liu, Zongwen

    2017-02-01

    Ultrafast and broad spectral bandwidth photodetectors are desirable attributable to their unique bandstructures. Photodetectors based on graphene have great potential due to graphene's outstanding optical and electrical properties. However, the highest reported values of the photoresponsivity of pure graphene are less than 10 mA/W at room temperature, which significantly limits its potential applications. Here, we report a photoresponsivity of 32 A/W in pure monolayer graphene photodetectors, an improvement of over one order of magnitude for functional graphene nanostructures (<3 A/W). The high photocurrent generation in our devices can be attributed to the high sensitivity of graphene's resistivity to a local change of the electric field induced by photo-excited carriers generated in the light-doping substrate. This dramatically increases the feasibility of using graphene for the next generation of photodetectors.

  9. Pure climb creep mechanism drives flow in Earth's lower mantle.

    PubMed

    Boioli, Francesca; Carrez, Philippe; Cordier, Patrick; Devincre, Benoit; Gouriet, Karine; Hirel, Pierre; Kraych, Antoine; Ritterbex, Sebastian

    2017-03-01

    At high pressure prevailing in the lower mantle, lattice friction opposed to dislocation glide becomes very high, as reported in recent experimental and theoretical studies. We examine the consequences of this high resistance to plastic shear exhibited by ringwoodite and bridgmanite on creep mechanisms under mantle conditions. To evaluate the consequences of this effect, we model dislocation creep by dislocation dynamics. The calculation yields to an original dominant creep behavior for lower mantle silicates where strain is produced by dislocation climb, which is very different from what can be activated under high stresses under laboratory conditions. This mechanism, named pure climb creep, is grain-size-insensitive and produces no crystal preferred orientation. In comparison to the previous considered diffusion creep mechanism, it is also a more efficient strain-producing mechanism for grain sizes larger than ca. 0.1 mm. The specificities of pure climb creep well match the seismic anisotropy observed of Earth's lower mantle.

  10. Biomedical effects of mushrooms with emphasis on pure compounds.

    PubMed

    Paterson, R Russell M; Lima, Nelson

    2014-01-01

    Medicinal mushrooms show great promise for disease treatments. They have been employed in the Orient and Occident for thousands of years, although the practice has persisted in the East. They remain highly valuable. Authentic human trials and pure compounds are emphasized in this review of the most current literature. Polysaccharides from the fungi appear effective in cancer treatments and low-molecular-weight compounds also attract much interest. However, reports of toxicity must be taken seriously. Prescriptions for mushrooms and preparations need to be given by qualified medical practitioners. The reason why these preparations are not more widely used in the West is related to problems of (A) intellectual property rights, (B) mass production, and (C) obtaining pure compounds that retain activity. Mushroom compounds require testing against infectious diseases such as those caused by bacteria, because the current antibiotics are failing from resistances. Overall, the future is assured for medicinal mushrooms.

  11. Direct Observation of High Photoresponsivity in Pure Graphene Photodetectors.

    PubMed

    Liu, Yanping; Xia, Qinglin; He, Jun; Liu, Zongwen

    2017-12-01

    Ultrafast and broad spectral bandwidth photodetectors are desirable attributable to their unique bandstructures. Photodetectors based on graphene have great potential due to graphene's outstanding optical and electrical properties. However, the highest reported values of the photoresponsivity of pure graphene are less than 10 mA/W at room temperature, which significantly limits its potential applications. Here, we report a photoresponsivity of 32 A/W in pure monolayer graphene photodetectors, an improvement of over one order of magnitude for functional graphene nanostructures (<3 A/W). The high photocurrent generation in our devices can be attributed to the high sensitivity of graphene's resistivity to a local change of the electric field induced by photo-excited carriers generated in the light-doping substrate. This dramatically increases the feasibility of using graphene for the next generation of photodetectors.

  12. Control aspects of quantum computing using pure and mixed states.

    PubMed

    Schulte-Herbrüggen, Thomas; Marx, Raimund; Fahmy, Amr; Kauffman, Louis; Lomonaco, Samuel; Khaneja, Navin; Glaser, Steffen J

    2012-10-13

    Steering quantum dynamics such that the target states solve classically hard problems is paramount to quantum simulation and computation. And beyond, quantum control is also essential to pave the way to quantum technologies. Here, important control techniques are reviewed and presented in a unified frame covering quantum computational gate synthesis and spectroscopic state transfer alike. We emphasize that it does not matter whether the quantum states of interest are pure or not. While pure states underly the design of quantum circuits, ensemble mixtures of quantum states can be exploited in a more recent class of algorithms: it is illustrated by characterizing the Jones polynomial in order to distinguish between different (classes of) knots. Further applications include Josephson elements, cavity grids, ion traps and nitrogen vacancy centres in scenarios of closed as well as open quantum systems.

  13. Pure angular momentum generator using a ring resonator.

    PubMed

    Yu, Y F; Fu, Y H; Zhang, X M; Liu, A Q; Bourouina, T; Mei, T; Shen, Z X; Tsai, D P

    2010-10-11

    This paper reports a pure angular momentum generator using a ring resonator surrounded by a group of nano-rods. The evanescent waves of the circulating light in the ring are scattered by the nano-rods and generate a rotating electromagnetic field, which has only angular momentum but no linear momentum along the axis of rotation. The angular order is determined by the difference between the order of Whispering Gallery mode and the number of the rods, the rotating frequency is equal to the light frequency divided by the angular order. The maximum amplitude of the rotating electromagnetic fields can be 10 times higher than the amplitude of the input field when there are 36 rods (R(rod) = 120 nm, nr = 1.6). The pure angular momentum generator provides a new platform for trapping and rotation of small particles.

  14. Control aspects of quantum computing using pure and mixed states

    PubMed Central

    Schulte-Herbrüggen, Thomas; Marx, Raimund; Fahmy, Amr; Kauffman, Louis; Lomonaco, Samuel; Khaneja, Navin; Glaser, Steffen J.

    2012-01-01

    Steering quantum dynamics such that the target states solve classically hard problems is paramount to quantum simulation and computation. And beyond, quantum control is also essential to pave the way to quantum technologies. Here, important control techniques are reviewed and presented in a unified frame covering quantum computational gate synthesis and spectroscopic state transfer alike. We emphasize that it does not matter whether the quantum states of interest are pure or not. While pure states underly the design of quantum circuits, ensemble mixtures of quantum states can be exploited in a more recent class of algorithms: it is illustrated by characterizing the Jones polynomial in order to distinguish between different (classes of) knots. Further applications include Josephson elements, cavity grids, ion traps and nitrogen vacancy centres in scenarios of closed as well as open quantum systems. PMID:22946034

  15. Assessment of semen quality in pure and crossbred Jersey bulls

    PubMed Central

    Kumar, Umesh; Gawande, Ajay P.; Sahatpure, Sunil K.; Patil, Manoj S.; Lakde, Chetan K.; Bonde, Sachin W.; Borkar, Pradnyankur L.; Poharkar, Ajay J.; Ramteke, Baldeo R.

    2015-01-01

    Aim: To compare the seminal attributes of neat, pre-freeze (at equilibration), and post-freeze (24 h after freezing) semen in pure and crossbred Jersey bulls. Materials and Methods: Total 36 ejaculates (3 ejaculates from each bull) were collected from 6 pure Jersey and 6 crossbred Jersey bulls and evaluated for various seminal attributes during neat, pre-freeze, and post-freeze semen. Results: The mean (±standard error [SE]) values of neat semen characteristics in pure and crossbred Jersey bulls were recorded such as volume (ml), color, consistency, mass activity (scale: 0-5), and sperm concentration (millions/ml). The extended semen was further investigated at pre-freeze and post-freeze stages and the mean (±SE) values recorded at neat, pre-freeze, and post-freeze semen were compared between pure and crossbred Jersey bulls; sperm motility (80.55±1.70%, 62.77±1.35%, 46.11±1.43% vs. 80.00±1.80%, 65.00±1.66%, 47.22±1.08%), live sperm count (83.63±1.08%, 71.72±1.09%, 58.67±1.02% vs. 80.00±1.08%, 67.91±1.20%, 51.63±0.97%), total abnormal sperm count (8.38±0.32%, 12.30±0.39%, 16.75±0.42% vs. 9.00±0.45%, 12.19±0.48%, 18.11±0.64%), hypo-osmotic swelling (HOS) reacted spermatozoa (71.88±0.77%, 62.05±0.80%, 47.27±1.05% vs. 72.77±1.02%, 62.11±0.89%, 45.94±1.33%), acrosome integrity (89.05±0.83%, 81.33±0.71%, 71.94±0.86% vs. 86.55±0.57%, 78.66±0.42%, 69.38±0.53%), and DNA integrity (99.88±0.07%, 100, 99.66±0.11% vs. 99.94±0.05%, 100, 99.44±0.18%,). The volume, color, consistency, sperm concentration, and initial motility in pure and crossbred Jersey bulls did not differ significantly (p>0.05). The mass activity was significantly (p<0.05) higher in pure Jersey as compare to crossbred Jersey bulls. Live sperm percentage and acrosome integrity was significantly (p<0.01) higher in pure Jersey bulls as compared to crossbred Jersey bulls. However, no statistical difference (p>0.05) was observed in abnormal sperm; HOS reacted spermatozoa and DNA

  16. A case of pure autotopagnosia following Creutzfeldt-Jakob disease.

    PubMed

    Tamura, Itaru; Hamada, Shinsuke; Soma, Hiroyuki; Moriwaka, Fumio; Tashiro, Kunio

    2016-12-02

    A 69-year-old male (N.A.) with Creutzfeldt-Jakob disease showed pure autotopagnosia. We administered tests evaluating his ability to name his own body parts, to point to body parts (his own and examiner's), and to recognize positional relationships between his body parts by verbal questions and responses. We found impaired localization of the patient's own body parts by pointing and impaired recognition of positional relationships between his body parts. However, there was no impairment in naming his own body parts or in localizing the examiner's body parts. The results suggest a pure autotopagnosia in N.A. leading to an impairment of recognition of the spatial position of his body parts in a three-dimensional body representation within the egocentric reference frame. We were able to rule out the possibility that his pattern of performance could have been due to a disability in programming reaching movements of the arm.

  17. [The corrosion of pure iron in five different mediums].

    PubMed

    Xu, Li; Zhu, Shengfa; Huang, Nan; Li, Xinchang; Zhang, Yu

    2009-08-01

    The sectional test was adopted in this study to investigate the corrosion of pure iron in 0.15 mol/L NaCl solution, Ringer solution, PBS(-) solution, SBF solution and M199 cell culture medium at three different times. The result shows that different mediums have different corrosion effects on pure iron. The arrangement according to the medium's corrosion ability from the strongest to weakest is 0.15 mol/L NaCl solution (Ringer solution), PBS(-) solution, SBF solution and M199 cell culture medium. The results of scanning electron microscopy and energy dispersive X-ray spectrum analyses show that the addition of HPO4(2-), H2POC4-, Ca2+, Mg2+, SO4(2-) and the organic component can inhibit the corrosion to some degree.

  18. Multiscale Monte Carlo equilibration: Pure Yang-Mills theory

    NASA Astrophysics Data System (ADS)

    Endres, Michael G.; Brower, Richard C.; Detmold, William; Orginos, Kostas; Pochinsky, Andrew V.

    2015-12-01

    We present a multiscale thermalization algorithm for lattice gauge theory, which enables efficient parallel generation of uncorrelated gauge field configurations. The algorithm combines standard Monte Carlo techniques with ideas drawn from real space renormalization group and multigrid methods. We demonstrate the viability of the algorithm for pure Yang-Mills gauge theory for both heat bath and hybrid Monte Carlo evolution, and show that it ameliorates the problem of topological freezing up to controllable lattice spacing artifacts.

  19. Pure subrings of the rings Z{sub {chi}}

    SciTech Connect

    Tsarev, Andrei V

    2009-10-31

    Pure subrings of finite rank in the Z-adic completion of the ring of integers and in its homomorphic images are considered. Certain properties of these rings are studied (existence of an identity element, decomposability into a direct sum of essentially indecomposable ideals, condition for embeddability into a csp-ring, etc.). Additive groups of these rings and conditions under which these rings are subrings of algebraic number fields are described. Bibliography: 12 titles.

  20. Pure Red Cell Aplasia Associated with Good Syndrome

    PubMed Central

    Okui, Masayuki; Yamamichi, Takashi; Asakawa, Ayaka; Harada, Masahiko; Horio, Hirotoshi

    2017-01-01

    Pure red cell aplasia (PRCA) and hypogammaglobulinemia are paraneoplastic syndromes that are rarer than myasthenia gravis in patients with thymoma. Good syndrome coexisting with PRCA is an extremely rare pathology. We report the case of a 50-year-old man with thymoma and PRCA associated with Good syndrome who achieved complete PRCA remission after thymectomy and postoperative immunosuppressive therapy, and provide a review of the pertinent literature. PMID:28382272

  1. On conformally flat and type N pure radiation metrics

    NASA Astrophysics Data System (ADS)

    Podolský, Jiří; Prikryl, Ondřej

    2009-05-01

    We study pure radiation spacetimes of algebraic types O and N with a possible cosmological constant. In particular, we present explicit transformations which put these metrics, that were recently re-derived by Edgar, Vickers and Machado Ramos, into a general Ozsváth-Robinson-Rózga form. By putting all such metrics into the unified coordinate system we confirm that their derivation based on the GIF formalism is correct. We identify only few trivial differences.

  2. A novel precursor for synthesis of pure boron nitride nanotubes.

    PubMed

    Tang, Chengchun; Bando, Yoshio; Sato, Tadao; Kurashima, Keiji

    2002-06-21

    A novel precursor, a mixture of B2O2 and Mg which is generated in situ by reacting B and MgO at 1300 degrees C, can be used to effectively synthesize bulk amounts of pure BN nanotubes with Mg evaporated from the final product; transmission electron microscope observation for the synthesized BN nanotubes indicates that defects present strongly depend on the tube diameter.

  3. Undercooling of pure metals in a containerless, microgravity environment

    NASA Technical Reports Server (NTRS)

    Robinson, M. B.; Bayuzick, R. J.; Hofmeister, W. H.

    1986-01-01

    The 105-m drop tube at NASA/Marshall Space Flight Center has been used in a series of undercooling experiments on pure metals. Ti, Zr, Nb, Mo, Rh, Hf, Ta, and Pt were undercooled 17-20 percent of the melting temperature in a containerless, microgravity environment. Ir and Ru were undercooled to 13 percent Tm. Sample sizes ranged from 175 to 880 mg.

  4. Lateral Stress Measurements in Pure Tungsten during Shock Loading

    SciTech Connect

    Millett, J. C. F.; Gray, G. T. III; Bourne, N. K.

    2006-07-28

    Longitudinal and lateral stresses during the shock loading of pure tungsten have been measured using manganin stress gauges. The Hugoniot has been compared to the previous work of others and shown to be in close agreement. Lateral stresses have been shown to increase behind the shock front, implying that the shear strength decreases. Whilst this is similar to results in tantalum, comparison with recovery experiments in the literature suggests that this may be due in part to a brittle failure process.

  5. BARKHAUSEN EFFECT IN IRRADIATED PURE IRON AND NICKEL.

    DTIC Science & Technology

    The effect of electron and neutron irradiation on the Barkhausen effect and coercive force of pure iron and nickel were investigated. The...investigation was designed to establish whether (l) the Barkhausen effect can provide a sensitive indication of the presence of large radiation-induced defect...clusters and whether (2) study of the Barkhausen effect could provide meaningful information about behavior of such defects. (These aims were based on

  6. Pure Protein Bilayers and Vesicles from Native Fungal Hydrophobins.

    PubMed

    Hähl, Hendrik; Vargas, Jose Nabor; Griffo, Alessandra; Laaksonen, Päivi; Szilvay, Géza; Lienemann, Michael; Jacobs, Karin; Seemann, Ralf; Fleury, Jean-Baptiste

    2017-01-01

    Pure protein bilayers and vesicles are formed using the native, fungal hydrophobin HFBI. Bilayers with hydrophobic (red) and hydrophilic (blue) core are produced and, depending on the type of core, vesicles in water, oily media, and even in air can be created using microfluidic jetting. Vesicles in water are even able to incorporate functional gramicidin A pores. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Gravitation, Electromagnetism and Cosmological Constant in Purely Affine Gravity

    NASA Astrophysics Data System (ADS)

    Popławski, Nikodem J.

    2009-03-01

    The Ferraris-Kijowski purely affine Lagrangian for the electromagnetic field, that has the form of the Maxwell Lagrangian with the metric tensor replaced by the symmetrized Ricci tensor, is dynamically equivalent to the metric Einstein-Maxwell Lagrangian, except the zero-field limit, for which the metric tensor is not well-defined. This feature indicates that, for the Ferraris-Kijowski model to be physical, there must exist a background field that depends on the Ricci tensor. The simplest possibility, supported by recent astronomical observations, is the cosmological constant, generated in the purely affine formulation of gravity by the Eddington Lagrangian. In this paper we combine the electromagnetic field and the cosmological constant in the purely affine formulation. We show that the sum of the two affine (Eddington and Ferraris-Kijowski) Lagrangians is dynamically inequivalent to the sum of the analogous ( ΛCDM and Einstein-Maxwell) Lagrangians in the metric-affine/metric formulation. We also show that such a construction is valid, like the affine Einstein-Born-Infeld formulation, only for weak electromagnetic fields, on the order of the magnetic field in outer space of the Solar System. Therefore the purely affine formulation that combines gravity, electromagnetism and cosmological constant cannot be a simple sum of affine terms corresponding separately to these fields. A quite complicated form of the affine equivalent of the metric Einstein-Maxwell- Λ Lagrangian suggests that Nature can be described by a simpler affine Lagrangian, leading to modifications of the Einstein-Maxwell- ΛCDM theory for electromagnetic fields that contribute to the spacetime curvature on the same order as the cosmological constant.

  8. Pure alexia and right hemiachromatopsia in posterior dementia.

    PubMed Central

    Freedman, L; Costa, L

    1992-01-01

    A 66 year old, right handed woman presented with pure alexia and right hemiachromatopsia (PARH) in the context of a posterior dementia. PARH was accompanied by prosopagnosia, 2-D object agnosia, and environmental agnosia. Visual fields were normal to confrontation testing. The pathological anatomy of PARH involves circumscribed damage to the lingual and fusiform gyri and paraventricular white matter of the left occipital cortex, two contiguous cortical regions functionally specialised for processing colour and word form information, respectively. PMID:1619420

  9. Optical absorption of pure water in the blue and ultraviolet

    NASA Astrophysics Data System (ADS)

    Lu, Zheng

    The key feature of the Integrating Cavity Absorption Meter (ICAM) is that it produces an isotropic illumination of the liquid sample and thereby dramatically minimizes scattering effects. The ICAM can produce an effective optical path length up to several meters. As a consequence, it is capable of measuring absorption coefficients as low as 0.001 m-1. The early version of the ICAM was used previously to measure the absorption spectrum of pure water over the 380-700 nm range. To extend its range into the ultraviolet, several modifications have been completed. The preliminary tests showed that the modified ICAM was able to measure the absorption of pure water for the wavelength down to 300 nm. After extensive experimental investigation and analysis, we found that the absorption of SpectralonRTM (the highly diffusive and reflective material used to build the ICAM) has a higher impact on measurements of absorption in the UV range than we had expected. Observations of high values for pure water absorption in the UV, specifically between 300 and 360 nm, are a consequence of absorption by the Spectralon RTM. These results indicated that even more serious modifications were required (e.g. SpectralonRTM can not be used for a cavity in the UV). Consequently, we developed a new diffuse reflecting material and used fused silica powder (sub-micron level) sealed inside a quartz cell to replace the inner SpectralonRTM cavity of the ICAM. The new data is in excellent agreement with the Pope and Fry data (380-600 nm) and fills the gap between the 320 nm data of Quickenden and Irvin and 380 nm data of Pope and Fry. We present definitive results for the absorption spectrum of pure water between 300 and 600 nm.

  10. Pure isobutylene from C/sub 4/ mix

    SciTech Connect

    Miranda, M.

    1987-08-01

    This article points out that the ADIB process can isolate and purify isobutylene from a butane-butylene stream such as might be obtained from catalytic and thermal crackers. The process uses the selectivity of the alkylation reaction between isobutylene and phenol. The alkylate product, a liquid that is easily separated from the gaseous feed, is then dealkylated to yield pure isobutylene and the recycle phenol.

  11. Evaluation of the Draeger LAR V Pure Oxygen Scuba

    DTIC Science & Technology

    1975-10-08

    SUPPLEMENTARY NOTES 19. KEY WORDS (Continue on reverse aide If necessar’y and identify by block number) r- SCUBA -PURE OXYGEN CLOSED CIRCUIT OXYGEN A03UTRACT...apparatus des~igned and manufactured in the Federal Republic of Germany. The scuba is completely closed circuit and incorporates a demand type oxygen supply...incorporates many inherent design features which makes it easier to pre/post dive and to maintain than the Emerein closed circuit scuba Test were conducted by

  12. Postencephalitic pure anomic aphasia: 2-year follow-up.

    PubMed

    Okuda, B; Kawabata, K; Tachibana, H; Sugita, M; Tanaka, H

    2001-06-15

    We report a patient with pure anomic aphasia following encephalitis. Brain magnetic resonance imaging (MRI) revealed bilateral temporal lesions, and subsequent focal atrophy in the left anterior inferior temporal lobe. Over the course of a 2-year follow-up, the patient's naming difficulty persisted without other dysfunction of language or memory. These observations indicate a contribution of the left anterior inferior temporal region to object naming.

  13. Pure versus hybrid: performance implications of Porter's generic strategies.

    PubMed

    Kumar, K; Subramanian, R; Yauger, C

    1997-01-01

    This article identifies the strategic types in the hospital industry based on the hospital's use of Porter's generic strategies in their pure and hybrid forms. The article also examines differences in performance of hospitals across strategic types. Results indicate that hospitals that follow a focussed cost leadership strategy, in general, have superior performance on a variety of performance measures, while hospitals that use a combination of cost leadership and differentiation perform the poorest. Implications of findings for hospital administrators are also discussed.

  14. Evidence for Ubiquitous High-equivalent-width Nebular Emission in z ~ 7 Galaxies: Toward a Clean Measurement of the Specific Star-formation Rate Using a Sample of Bright, Magnified Galaxies

    NASA Astrophysics Data System (ADS)

    Smit, R.; Bouwens, R. J.; Labbé, I.; Zheng, W.; Bradley, L.; Donahue, M.; Lemze, D.; Moustakas, J.; Umetsu, K.; Zitrin, A.; Coe, D.; Postman, M.; Gonzalez, V.; Bartelmann, M.; Benítez, N.; Broadhurst, T.; Ford, H.; Grillo, C.; Infante, L.; Jimenez-Teja, Y.; Jouvel, S.; Kelson, D. D.; Lahav, O.; Maoz, D.; Medezinski, E.; Melchior, P.; Meneghetti, M.; Merten, J.; Molino, A.; Moustakas, L. A.; Nonino, M.; Rosati, P.; Seitz, S.

    2014-03-01

    Growing observational evidence indicates that nebular line emission has a significant impact on the rest-frame optical fluxes of z ~ 5-7 galaxies. This line emission makes z ~ 5-7 galaxies appear more massive, with lower specific star-formation rates (sSFRs). However, corrections for this line emission have been difficult to perform reliably because of huge uncertainties on the strength of such emission at z >~ 5.5. In this paper, we present the most direct observational evidence thus far for ubiquitous high-equivalent-width (EW) [O III] + Hβ line emission in Lyman-break galaxies at z ~ 7, and we present a strategy for an improved measurement of the sSFR at z ~ 7. We accomplish this through the selection of bright galaxies in the narrow redshift window z ~ 6.6-7.0 where the Spitzer/Infrared Array Camera (IRAC) 4.5 μm flux provides a clean measurement of the stellar continuum light, in contrast with the 3.6 μm flux, which is contaminated by the prominent [O III] + Hβ lines. To ensure a high signal-to-noise ratio for our IRAC flux measurements, we consider only the brightest (H 160 < 26 mag) magnified galaxies we have identified behind galaxy clusters. It is remarkable that the mean rest-frame optical color for our bright seven-source sample is very blue, [3.6]-[4.5] = -0.9 ± 0.3. Such blue colors cannot be explained by the stellar continuum light and require that the rest-frame EW of [O III] + Hβ is greater than 637 Å for the average source. The four bluest sources from our seven-source sample require an even more extreme EW of 1582 Å. We can also set a robust lower limit of >~ 4 Gyr-1 on the sSFR of our sample based on the mean spectral energy distribution.

  15. Magnetization oscillations and waves driven by pure spin currents

    NASA Astrophysics Data System (ADS)

    Demidov, V. E.; Urazhdin, S.; de Loubens, G.; Klein, O.; Cros, V.; Anane, A.; Demokritov, S. O.

    2017-02-01

    Recent advances in the studies of pure spin currents-flows of angular momentum (spin) not accompanied by the electric currents-have opened new horizons for the emerging technologies based on the electron's spin degree of freedom, such as spintronics and magnonics. The main advantage of pure spin current, as compared to the spin-polarized electric current, is the possibility to exert spin transfer torque on the magnetization in thin magnetic films without the electrical current flow through the material. In addition to minimizing Joule heating and electromigration effects, this enables the implementation of spin torque devices based on the low-loss insulating magnetic materials, and offers an unprecedented geometric flexibility. Here we review the recent experimental achievements in investigations of magnetization oscillations excited by pure spin currents in different nanomagnetic systems based on metallic and insulating magnetic materials. We discuss the spectral properties of spin-current nano-oscillators, and relate them to the spatial characteristics of the excited dynamic magnetic modes determined by the spatially-resolved measurements. We also show that these systems support locking of the oscillations to external microwave signals, as well as their mutual synchronization, and can be used as efficient nanoscale sources of propagating spin waves.

  16. Diagnosing pure-electron plasmas with internal particle flux probes.

    PubMed

    Kremer, J P; Pedersen, T Sunn; Marksteiner, Q; Lefrancois, R G; Hahn, M

    2007-01-01

    Techniques for measuring local plasma potential, density, and temperature of pure-electron plasmas using emissive and Langmuir probes are described. The plasma potential is measured as the least negative potential at which a hot tungsten filament emits electrons. Temperature is measured, as is commonly done in quasineutral plasmas, through the interpretation of a Langmuir probe current-voltage characteristic. Due to the lack of ion-saturation current, the density must also be measured through the interpretation of this characteristic thereby greatly complicating the measurement. Measurements are further complicated by low densities, low cross field transport rates, and large flows typical of pure-electron plasmas. This article describes the use of these techniques on pure-electron plasmas in the Columbia Non-neutral Torus (CNT) stellarator. Measured values for present baseline experimental parameters in CNT are phi(p)=-200+/-2 V, T(e)=4+/-1 eV, and n(e) on the order of 10(12) m(-3) in the interior.

  17. Analysis of Ultra-Pure Gases by Ion Mobility Spectrometry

    NASA Technical Reports Server (NTRS)

    Stimac, Robert M.; Wernlund, Roger F.; Cohen, Martin J.

    1995-01-01

    Work has continued with the evaluation of the Ion Mobility Spectrometer (IMS) for the analysis of gases having low parts-per-billion (10(exp -9)) water concentration. A modified PCP, inc. MMS-160 Mobility Mass Spectrometer System was used for the analysis of ultra-pure argon and nitrogen. The MMS-160 system permits the mass-identification of unique reactant and product ions observed in the reduced-water host gases. When the water is removed to low ppb levels, higher energy reactant ions are observed. In nitrogen, distinct odd- and even-numbered nitrogen cluster ion mobility peaks are observed, as well as adduct ion peaks from the trace contaminants in the gas. Argon also produces a cluster ion mobility peak and adduct ion peaks from trace components in the gas. Levels of contaminants in these ultra-pure gases can be determined from the ion mobility spectra. A calibrated source was used to provide variable known quantities of water to the pure gas supply of the IMS.

  18. Analysis of Ultra-Pure Gases by Ion Mobility Spectrometry

    NASA Technical Reports Server (NTRS)

    Stimac, Robert M.; Wernlund, Roger F.; Cohen, Martin J.

    1995-01-01

    Work has continued with the evaluation of the Ion Mobility Spectrometer (IMS) for the analysis of gases having low parts-per-billion (10(exp -9)) water concentration. A modified PCP, inc. MMS-160 Mobility Mass Spectrometer System was used for the analysis of ultra-pure argon and nitrogen. The MMS-160 system permits the mass-identification of unique reactant and product ions observed in the reduced-water host gases. When the water is removed to low ppb levels, higher energy reactant ions are observed. In nitrogen, distinct odd- and even-numbered nitrogen cluster ion mobility peaks are observed, as well as adduct ion peaks from the trace contaminants in the gas. Argon also produces a cluster ion mobility peak and adduct ion peaks from trace components in the gas. Levels of contaminants in these ultra-pure gases can be determined from the ion mobility spectra. A calibrated source was used to provide variable known quantities of water to the pure gas supply of the IMS.

  19. Path integral regularization of pure Yang-Mills theory

    SciTech Connect

    Jacquot, J. L.

    2009-07-15

    In enlarging the field content of pure Yang-Mills theory to a cutoff dependent matrix valued complex scalar field, we construct a vectorial operator, which is by definition invariant with respect to the gauge transformation of the Yang-Mills field and with respect to a Stueckelberg type gauge transformation of the scalar field. This invariant operator converges to the original Yang-Mills field as the cutoff goes to infinity. With the help of cutoff functions, we construct with this invariant a regularized action for the pure Yang-Mills theory. In order to be able to define both the gauge and scalar fields kinetic terms, other invariant terms are added to the action. Since the scalar fields flat measure is invariant under the Stueckelberg type gauge transformation, we obtain a regularized gauge-invariant path integral for pure Yang-Mills theory that is mathematically well defined. Moreover, the regularized Ward-Takahashi identities describing the dynamics of the gauge fields are exactly the same as the formal Ward-Takahashi identities of the unregularized theory.

  20. The prospects for polarized target materials with pure carbon background

    SciTech Connect

    Hill, D.A.

    1992-10-06

    None of the materials presently in common use for polarized proton targets has a pure carbon nuclear background. The alcohols and diols contain some oxygen, and the ammonia and amine-based materials contain nitrogen and/or other noncarbon species. In the latter cases the noncarbon nuclei are measurably polarized as a concomitant of the process used to polarize the hydrogen nuclei. The relative simplicity of a pure carbon background would be advantageous for most types of scattering experiments and perhaps crucial for some. In addition to simplifying the kinematics of background events, pure carbon is relatively easy to prepare as a dummy'' target for background subtraction. Also, in such a target material, [sup 13]C-enrichment would yield a clean polarized [sup 13]C material. In this note I explore the possibilities for such materials, touching upon only what I consider to be the high'' points. The subject matter is capable of nearly endless ramification and speculation. In fact, owing to a general lack of relevant experimental data, even this relatively brief note contains much that is speculative to some degree.